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rdf:resource="https://www.mdpi.com/2075-1702/12/11/754" /> </rdf:Seq> </items> <cc:license rdf:resource="https://creativecommons.org/licenses/by/4.0/" /> </channel> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/854"> <title>Machines, Vol. 12, Pages 854: Active Control of Shimmy in Articulated Single-Axle Straddle-Type Monorail Train</title> <link>https://www.mdpi.com/2075-1702/12/12/854</link> <description>The articulated single-axle straddle-type monorail train has many unique advantages, making it the preferred choice for medium-capacity urban rail transit. However, the issue of vehicle shimmy greatly restricts its promotion and application. In response to this issue, an active suspension control scheme is proposed, and the corresponding control algorithm is designed. Considering economic and feasible factors, a modification plan for the single-axle bogie without changing the original structure is proposed. A closed-loop feedback control strategy with lateral velocity and yaw rate as control objectives is designed, and a 114 degree-of-freedom dynamic model of a monorail train is established. Taking the skyhook damping control as the reference model, the SH-SMC (skyhook-sliding mode control) active control scheme is designed based on the sliding mode control theory. Considering practical applications, the control force distribution algorithm is further proposed. Through co-simulation of UM and Matlab, different control schemes are compared and analyzed. The results indicate that the SH-SMC active control scheme is more effective in suppressing the shimmy of single-axle monorail train, verifying the effectiveness of the SH-SMC active control scheme. It is of great significance for the further promotion and application of single-axle monorail trains in more cities.</description> <pubDate>2024-11-26</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 854: Active Control of Shimmy in Articulated Single-Axle Straddle-Type Monorail Train Machines <a href="https://www.mdpi.com/2075-1702/12/12/854">doi: 10.3390/machines12120854</a> Authors: Jiachen Song Liwei Zhang Dongjin Zhu Hui Liang The articulated single-axle straddle-type monorail train has many unique advantages, making it the preferred choice for medium-capacity urban rail transit. However, the issue of vehicle shimmy greatly restricts its promotion and application. In response to this issue, an active suspension control scheme is proposed, and the corresponding control algorithm is designed. Considering economic and feasible factors, a modification plan for the single-axle bogie without changing the original structure is proposed. A closed-loop feedback control strategy with lateral velocity and yaw rate as control objectives is designed, and a 114 degree-of-freedom dynamic model of a monorail train is established. Taking the skyhook damping control as the reference model, the SH-SMC (skyhook-sliding mode control) active control scheme is designed based on the sliding mode control theory. Considering practical applications, the control force distribution algorithm is further proposed. Through co-simulation of UM and Matlab, different control schemes are compared and analyzed. The results indicate that the SH-SMC active control scheme is more effective in suppressing the shimmy of single-axle monorail train, verifying the effectiveness of the SH-SMC active control scheme. It is of great significance for the further promotion and application of single-axle monorail trains in more cities. ]]></content:encoded> <dc:title>Active Control of Shimmy in Articulated Single-Axle Straddle-Type Monorail Train</dc:title> <dc:creator>Jiachen Song</dc:creator> <dc:creator>Liwei Zhang</dc:creator> <dc:creator>Dongjin Zhu</dc:creator> <dc:creator>Hui Liang</dc:creator> <dc:identifier>doi: 10.3390/machines12120854</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-26</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-26</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Article</prism:section> <prism:startingPage>854</prism:startingPage> <prism:doi>10.3390/machines12120854</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/854</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/853"> <title>Machines, Vol. 12, Pages 853: A Biochemistry-Inspired Algorithm for Path Planning in Unmanned Ground Vehicles</title> <link>https://www.mdpi.com/2075-1702/12/12/853</link> <description>Unmanned ground vehicles (UGVs) have gained significant attention due to their extensive applications in both military and civilian sectors. For effective UGV deployment, path planning algorithms must prioritize computational efficiency, solution reliability, and runtime performance while maintaining path quality. Autonomous path planning remains a critical challenge in UGV navigation, as conventional methods, while effective, often suffer from considerable computational overhead. To address this issue, we propose a novel biochemistry-inspired path planning algorithm designed specifically for static grid-based scenarios. MetaPath demonstrates remarkable computational efficiency while maintaining solution quality across different obstacle densities in benchmark environments. Specifically, the algorithm achieves path lengths within &amp;plusmn;5% of all benchmark algorithms while dramatically reducing the exploration space, visiting up to 10% of the cells explored by conventional approaches such as A*. This superior efficiency translates into exceptional runtime performance, executing up to 3000 times faster than bio-inspired algorithms like Ant Colony Optimization (ACO) and the Genetic Algorithm (GA), performing nearly three times faster than the widely used A* algorithm, and maintaining competitive performance with efficient algorithms like Breadth-First Search (BFS) and Particle Swarm Optimization (PSO), thereby establishing the algorithm as a highly efficient pathfinding solution. Most notably, MetaPath introduces a novel approach as the first chemistry-inspired pathfinding algorithm, guaranteeing path discovery when one exists within reasonable computational time, a crucial advantage over some benchmark algorithms that may fail to converge or require excessive computational resources in complex scenarios.</description> <pubDate>2024-11-26</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 853: A Biochemistry-Inspired Algorithm for Path Planning in Unmanned Ground Vehicles Machines <a href="https://www.mdpi.com/2075-1702/12/12/853">doi: 10.3390/machines12120853</a> Authors: Eman Almoaili Heba Kurdi Unmanned ground vehicles (UGVs) have gained significant attention due to their extensive applications in both military and civilian sectors. For effective UGV deployment, path planning algorithms must prioritize computational efficiency, solution reliability, and runtime performance while maintaining path quality. Autonomous path planning remains a critical challenge in UGV navigation, as conventional methods, while effective, often suffer from considerable computational overhead. To address this issue, we propose a novel biochemistry-inspired path planning algorithm designed specifically for static grid-based scenarios. MetaPath demonstrates remarkable computational efficiency while maintaining solution quality across different obstacle densities in benchmark environments. Specifically, the algorithm achieves path lengths within &amp;plusmn;5% of all benchmark algorithms while dramatically reducing the exploration space, visiting up to 10% of the cells explored by conventional approaches such as A*. This superior efficiency translates into exceptional runtime performance, executing up to 3000 times faster than bio-inspired algorithms like Ant Colony Optimization (ACO) and the Genetic Algorithm (GA), performing nearly three times faster than the widely used A* algorithm, and maintaining competitive performance with efficient algorithms like Breadth-First Search (BFS) and Particle Swarm Optimization (PSO), thereby establishing the algorithm as a highly efficient pathfinding solution. Most notably, MetaPath introduces a novel approach as the first chemistry-inspired pathfinding algorithm, guaranteeing path discovery when one exists within reasonable computational time, a crucial advantage over some benchmark algorithms that may fail to converge or require excessive computational resources in complex scenarios. ]]></content:encoded> <dc:title>A Biochemistry-Inspired Algorithm for Path Planning in Unmanned Ground Vehicles</dc:title> <dc:creator>Eman Almoaili</dc:creator> <dc:creator>Heba Kurdi</dc:creator> <dc:identifier>doi: 10.3390/machines12120853</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-26</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-26</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Article</prism:section> <prism:startingPage>853</prism:startingPage> <prism:doi>10.3390/machines12120853</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/853</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/852"> <title>Machines, Vol. 12, Pages 852: Contributions to the Development of Tetrahedral Mobile Robots with Omnidirectional Locomotion Units</title> <link>https://www.mdpi.com/2075-1702/12/12/852</link> <description>In this paper, the authors present the process of modeling, building, and testing two prototypes of tetrahedral robots with omnidirectional locomotion units. The paper begins with a detailed description of the first tetrahedral robot prototype, highlighting its strengths as well as the limitations that led to the need for improvements. The robot&amp;rsquo;s omnidirectional movement allowed it to move in all directions, but certain challenges related to stability and adaptability were identified. The second prototype is presented as an advanced and improved version of the first model, integrating significant modifications in both the structural design and the robot&amp;rsquo;s functionality. The authors emphasize how these optimizations were achieved, detailing the solutions adopted and their impact on the robot&amp;rsquo;s overall performance. This paper includes an in-depth comparative analysis between the two prototypes. The analysis highlights the considerable advantages of the second prototype, demonstrating its superiority. The conclusions of the paper summarize the main findings of the research and emphasize the significant progress made from the first to the second prototype. Finally, future research directions are discussed, which include refining control algorithms, miniaturizing the robot, improving structural performance by integrating shock-absorbing dampers, and integrating lighting systems and video cameras.</description> <pubDate>2024-11-26</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 852: Contributions to the Development of Tetrahedral Mobile Robots with Omnidirectional Locomotion Units Machines <a href="https://www.mdpi.com/2075-1702/12/12/852">doi: 10.3390/machines12120852</a> Authors: Anca-Corina Simerean Mihai Olimpiu T膬tar In this paper, the authors present the process of modeling, building, and testing two prototypes of tetrahedral robots with omnidirectional locomotion units. The paper begins with a detailed description of the first tetrahedral robot prototype, highlighting its strengths as well as the limitations that led to the need for improvements. The robot&amp;rsquo;s omnidirectional movement allowed it to move in all directions, but certain challenges related to stability and adaptability were identified. The second prototype is presented as an advanced and improved version of the first model, integrating significant modifications in both the structural design and the robot&amp;rsquo;s functionality. The authors emphasize how these optimizations were achieved, detailing the solutions adopted and their impact on the robot&amp;rsquo;s overall performance. This paper includes an in-depth comparative analysis between the two prototypes. The analysis highlights the considerable advantages of the second prototype, demonstrating its superiority. The conclusions of the paper summarize the main findings of the research and emphasize the significant progress made from the first to the second prototype. Finally, future research directions are discussed, which include refining control algorithms, miniaturizing the robot, improving structural performance by integrating shock-absorbing dampers, and integrating lighting systems and video cameras. ]]></content:encoded> <dc:title>Contributions to the Development of Tetrahedral Mobile Robots with Omnidirectional Locomotion Units</dc:title> <dc:creator>Anca-Corina Simerean</dc:creator> <dc:creator>Mihai Olimpiu T膬tar</dc:creator> <dc:identifier>doi: 10.3390/machines12120852</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-26</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-26</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Article</prism:section> <prism:startingPage>852</prism:startingPage> <prism:doi>10.3390/machines12120852</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/852</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/851"> <title>Machines, Vol. 12, Pages 851: Intelligent Numerical Control Programming System Based on Knowledge Graph</title> <link>https://www.mdpi.com/2075-1702/12/12/851</link> <description>With the wide application of computer-aided manufacturing (CAM) software, manufacturing enterprises have accumulated a wealth of numerical control (NC) programming data, providing valuable knowledge resources for new products&amp;rsquo; development. Efficiently acquiring and reusing existing NC knowledge is essential for enhancing programming efficiency, improving product quality, and shortening manufacturing cycles. This study proposes an intelligent NC programming method based on knowledge graph. Firstly, the relevant knowledge in the NC programming domain is analyzed, and CAM knowledge elements are constructed to reduce the granularity of knowledge. Then, the ontology layer and data layer are constructed to achieve the development of the knowledge graph. Next, knowledge reasoning is performed on the knowledge graph through entity alignment and semantic rule-based reasoning. Furthermore, to address the issues of low reliability, limited applicability and need for frequent manual modifications in NC programming templates guided by the CAM knowledge graph, a CAM knowledge graph completion method based on neighborhood aggregation and semantic enhancement is proposed. Finally, an intelligent NC programming system based on knowledge graph is developed, and comparative experiments with mainstream algorithms on public datasets for few-shot knowledge graph completion are conducted, validating the effectiveness of the proposed method by experimenting with the key components of marine diesel engines.</description> <pubDate>2024-11-26</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 851: Intelligent Numerical Control Programming System Based on Knowledge Graph Machines <a href="https://www.mdpi.com/2075-1702/12/12/851">doi: 10.3390/machines12120851</a> Authors: Xifeng Fang Jiabao Su Dejun Cheng With the wide application of computer-aided manufacturing (CAM) software, manufacturing enterprises have accumulated a wealth of numerical control (NC) programming data, providing valuable knowledge resources for new products&amp;rsquo; development. Efficiently acquiring and reusing existing NC knowledge is essential for enhancing programming efficiency, improving product quality, and shortening manufacturing cycles. This study proposes an intelligent NC programming method based on knowledge graph. Firstly, the relevant knowledge in the NC programming domain is analyzed, and CAM knowledge elements are constructed to reduce the granularity of knowledge. Then, the ontology layer and data layer are constructed to achieve the development of the knowledge graph. Next, knowledge reasoning is performed on the knowledge graph through entity alignment and semantic rule-based reasoning. Furthermore, to address the issues of low reliability, limited applicability and need for frequent manual modifications in NC programming templates guided by the CAM knowledge graph, a CAM knowledge graph completion method based on neighborhood aggregation and semantic enhancement is proposed. Finally, an intelligent NC programming system based on knowledge graph is developed, and comparative experiments with mainstream algorithms on public datasets for few-shot knowledge graph completion are conducted, validating the effectiveness of the proposed method by experimenting with the key components of marine diesel engines. ]]></content:encoded> <dc:title>Intelligent Numerical Control Programming System Based on Knowledge Graph</dc:title> <dc:creator>Xifeng Fang</dc:creator> <dc:creator>Jiabao Su</dc:creator> <dc:creator>Dejun Cheng</dc:creator> <dc:identifier>doi: 10.3390/machines12120851</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-26</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-26</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Article</prism:section> <prism:startingPage>851</prism:startingPage> <prism:doi>10.3390/machines12120851</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/851</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/850"> <title>Machines, Vol. 12, Pages 850: Prediction Model of Pipeline Push Resistance in Tunnels</title> <link>https://www.mdpi.com/2075-1702/12/12/850</link> <description>The installation of pipes in tunnel construction using the external welding method requires the assistance of a pipe pusher and roller support to push the welded pipe into the tunnel. Accurate determination of pipeline push resistance and the selection of an appropriate pipe pusher model are crucial factors for successful construction. Currently, there is no effective method available for predicting push resistance, which may result in inaccurate estimation and inadequate thrust provided by the selected pipe pusher. Therefore, this study aims to establish a reliable formula for calculating push resistance through theoretical analysis and numerical simulation. Additionally, we investigate the rolling resistance coefficient between the pipe and roller wheel to develop a corresponding prediction formula. Finally, a test platform is set up to validate our proposed formula for estimating push resistance. The results demonstrate that there is approximately a 5% error between the calculated values and the test values, confirming that this method effectively predicts pipeline push resistance.</description> <pubDate>2024-11-26</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 850: Prediction Model of Pipeline Push Resistance in Tunnels Machines <a href="https://www.mdpi.com/2075-1702/12/12/850">doi: 10.3390/machines12120850</a> Authors: Lianmin Cao Mingxing Zhu Dekang Zhang Ying Zhen Xu Zhang Yuguang Cao The installation of pipes in tunnel construction using the external welding method requires the assistance of a pipe pusher and roller support to push the welded pipe into the tunnel. Accurate determination of pipeline push resistance and the selection of an appropriate pipe pusher model are crucial factors for successful construction. Currently, there is no effective method available for predicting push resistance, which may result in inaccurate estimation and inadequate thrust provided by the selected pipe pusher. Therefore, this study aims to establish a reliable formula for calculating push resistance through theoretical analysis and numerical simulation. Additionally, we investigate the rolling resistance coefficient between the pipe and roller wheel to develop a corresponding prediction formula. Finally, a test platform is set up to validate our proposed formula for estimating push resistance. The results demonstrate that there is approximately a 5% error between the calculated values and the test values, confirming that this method effectively predicts pipeline push resistance. ]]></content:encoded> <dc:title>Prediction Model of Pipeline Push Resistance in Tunnels</dc:title> <dc:creator>Lianmin Cao</dc:creator> <dc:creator>Mingxing Zhu</dc:creator> <dc:creator>Dekang Zhang</dc:creator> <dc:creator>Ying Zhen</dc:creator> <dc:creator>Xu Zhang</dc:creator> <dc:creator>Yuguang Cao</dc:creator> <dc:identifier>doi: 10.3390/machines12120850</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-26</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-26</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Article</prism:section> <prism:startingPage>850</prism:startingPage> <prism:doi>10.3390/machines12120850</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/850</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/848"> <title>Machines, Vol. 12, Pages 848: Coupling Interface Load Identification of Sliding Bearing in Wind Turbine Gearbox Based on Polynomial Structure Selection Technique</title> <link>https://www.mdpi.com/2075-1702/12/12/848</link> <description>Sliding bearings are widely used in wind turbine gearboxes, and the accurate identification of coupling interface loads is critical for ensuring the reliability and performance of these systems. However, the space&amp;ndash;time coupling nature of these loads makes them difficult to calculate and measure directly. An improved method utilizing the POD decomposition algorithm and polynomial selection technology is proposed in this paper to identify the sliding bearing coupling interface loads. By using the POD decomposition algorithm, the sliding bearing coupling interface loads can be decomposed into the form of a series of independent oil film time history and spatial distribution functions. Then, it can be converted into space&amp;ndash;time independent sub-coupled interface load identification in which oil film time history can be transformed into the recognition of a certain order modal load and the corresponding oil film spatial distribution function can be fitted with a set of Chebyshev orthogonal polynomial. To address the ill-posedness caused by the weak correlation between the modal matrix and polynomial options during the identification process, this paper introduces polynomial structure selection technology. Firstly, displacement responses are collected, and a series of modal loads are identified using conventional concentrated load identification methods. Then, the polynomial structure selection technology is applied to select the effective modal shape matrix, using a specific mode load as the oil film time history function. The load ratios of other mode loads to this reference mode load are compared, and the effective Chebyshev orthogonal polynomials are selected based on the error reduction ratio. Finally, multiplying the identified oil film time histories by the corresponding oil film spatial distribution functions yields the coupling interface load. The results of the numerical examples verify the improved method&amp;rsquo;s rationality and effectiveness.</description> <pubDate>2024-11-26</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 848: Coupling Interface Load Identification of Sliding Bearing in Wind Turbine Gearbox Based on Polynomial Structure Selection Technique Machines <a href="https://www.mdpi.com/2075-1702/12/12/848">doi: 10.3390/machines12120848</a> Authors: Wengui Mao Jie Wang Shixiong Pei Sliding bearings are widely used in wind turbine gearboxes, and the accurate identification of coupling interface loads is critical for ensuring the reliability and performance of these systems. However, the space&amp;ndash;time coupling nature of these loads makes them difficult to calculate and measure directly. An improved method utilizing the POD decomposition algorithm and polynomial selection technology is proposed in this paper to identify the sliding bearing coupling interface loads. By using the POD decomposition algorithm, the sliding bearing coupling interface loads can be decomposed into the form of a series of independent oil film time history and spatial distribution functions. Then, it can be converted into space&amp;ndash;time independent sub-coupled interface load identification in which oil film time history can be transformed into the recognition of a certain order modal load and the corresponding oil film spatial distribution function can be fitted with a set of Chebyshev orthogonal polynomial. To address the ill-posedness caused by the weak correlation between the modal matrix and polynomial options during the identification process, this paper introduces polynomial structure selection technology. Firstly, displacement responses are collected, and a series of modal loads are identified using conventional concentrated load identification methods. Then, the polynomial structure selection technology is applied to select the effective modal shape matrix, using a specific mode load as the oil film time history function. The load ratios of other mode loads to this reference mode load are compared, and the effective Chebyshev orthogonal polynomials are selected based on the error reduction ratio. Finally, multiplying the identified oil film time histories by the corresponding oil film spatial distribution functions yields the coupling interface load. The results of the numerical examples verify the improved method&amp;rsquo;s rationality and effectiveness. ]]></content:encoded> <dc:title>Coupling Interface Load Identification of Sliding Bearing in Wind Turbine Gearbox Based on Polynomial Structure Selection Technique</dc:title> <dc:creator>Wengui Mao</dc:creator> <dc:creator>Jie Wang</dc:creator> <dc:creator>Shixiong Pei</dc:creator> <dc:identifier>doi: 10.3390/machines12120848</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-26</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-26</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Article</prism:section> <prism:startingPage>848</prism:startingPage> <prism:doi>10.3390/machines12120848</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/848</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/849"> <title>Machines, Vol. 12, Pages 849: An Extend Sliding Mode Disturbance Observer for Optical Inertial Platform Line-of&ndash;Sight Stabilized Control</title> <link>https://www.mdpi.com/2075-1702/12/12/849</link> <description>As the imaging distance and focal length of photoelectric systems increase, the requirements for line-of&amp;ndash;sight stabilization of optical inertial stabilized platforms (ISPs) become higher. Disturbance rejection directly determines the stability accuracy of optical inertial stabilized platforms. However, the accurate observation and suppression of wide-band and rapidly changing disturbances remains a challenge in current engineering applications. This paper proposes a robust extended sliding mode observer (ESMO) method to improve disturbance estimation performance. First, the linear extended state observer (LESO) is designed by taking the total disturbances as extended states. Then, a sliding mode observer (SMO) is incorporated in the extended states of the extended observer, forming a robust ESMO. Subsequently, the robustness and convergence characteristics of the proposed method are mathematically proved, revealing that it operates robustly without knowing the disturbance&amp;rsquo;s upper bound and offers faster dynamics and higher accuracy than the LESO. Finally, a series of simulation experimental tests are performed to demonstrate the effectiveness of the proposed method. The proposed method observes wide-band and rapidly changing disturbances utilizing the rapidly switching characteristic of the SMO and smooths the jitter of the SMO by cascading sliding mode estimation to the differentiation term of extended observation, achieving the integral effect of the reaching law. Meanwhile, this method only requires adjusting two parameters, making it suitable for engineering applications. It can be effectively used in optical inertial stabilized platform control systems for disturbance estimation and compensation.</description> <pubDate>2024-11-26</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 849: An Extend Sliding Mode Disturbance Observer for Optical Inertial Platform Line-of&ndash;Sight Stabilized Control Machines <a href="https://www.mdpi.com/2075-1702/12/12/849">doi: 10.3390/machines12120849</a> Authors: Sansan Chang Di Yang Jianzhong Cao Xiang Li As the imaging distance and focal length of photoelectric systems increase, the requirements for line-of&amp;ndash;sight stabilization of optical inertial stabilized platforms (ISPs) become higher. Disturbance rejection directly determines the stability accuracy of optical inertial stabilized platforms. However, the accurate observation and suppression of wide-band and rapidly changing disturbances remains a challenge in current engineering applications. This paper proposes a robust extended sliding mode observer (ESMO) method to improve disturbance estimation performance. First, the linear extended state observer (LESO) is designed by taking the total disturbances as extended states. Then, a sliding mode observer (SMO) is incorporated in the extended states of the extended observer, forming a robust ESMO. Subsequently, the robustness and convergence characteristics of the proposed method are mathematically proved, revealing that it operates robustly without knowing the disturbance&amp;rsquo;s upper bound and offers faster dynamics and higher accuracy than the LESO. Finally, a series of simulation experimental tests are performed to demonstrate the effectiveness of the proposed method. The proposed method observes wide-band and rapidly changing disturbances utilizing the rapidly switching characteristic of the SMO and smooths the jitter of the SMO by cascading sliding mode estimation to the differentiation term of extended observation, achieving the integral effect of the reaching law. Meanwhile, this method only requires adjusting two parameters, making it suitable for engineering applications. It can be effectively used in optical inertial stabilized platform control systems for disturbance estimation and compensation. ]]></content:encoded> <dc:title>An Extend Sliding Mode Disturbance Observer for Optical Inertial Platform Line-of&amp;ndash;Sight Stabilized Control</dc:title> <dc:creator>Sansan Chang</dc:creator> <dc:creator>Di Yang</dc:creator> <dc:creator>Jianzhong Cao</dc:creator> <dc:creator>Xiang Li</dc:creator> <dc:identifier>doi: 10.3390/machines12120849</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-26</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-26</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Article</prism:section> <prism:startingPage>849</prism:startingPage> <prism:doi>10.3390/machines12120849</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/849</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/847"> <title>Machines, Vol. 12, Pages 847: A Soft Start Method for Doubly Fed Induction Machines Based on Synchronization with the Power System at Standstill Conditions</title> <link>https://www.mdpi.com/2075-1702/12/12/847</link> <description>Due to their exceptional operational versatility, doubly fed induction machines (DFIM) are widely employed in power systems comprising variable renewable energy-based electrical generation sources, such as wind farms and pumped-storage hydropower plants. However, their starting and grid synchronization methods require numerous maneuvers or additional components, making the process challenging. In this paper, a soft start method for DFIM, inspired by the traditional synchronization method of synchronous machines, is proposed. This method involves matching the frequencies, voltages, and phase angles on both sides of the main circuit breaker, by adjusting the excitation through the controlled power converter at standstill conditions. Once synchronization is achieved, the frequency is gradually reduced to the rated operational levels. This straightforward starting method effectively suppresses large inrush currents and voltage sags. The proposed method has been validated through computer simulations and experimental tests, yielding satisfactory results.</description> <pubDate>2024-11-25</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 847: A Soft Start Method for Doubly Fed Induction Machines Based on Synchronization with the Power System at Standstill Conditions Machines <a href="https://www.mdpi.com/2075-1702/12/12/847">doi: 10.3390/machines12120847</a> Authors: Jos茅 M. Guerrero Kumar Mahtani Itxaso Aranzabal Julen G贸mez-Cornejo Jos茅 A. S谩nchez Carlos A. Platero Due to their exceptional operational versatility, doubly fed induction machines (DFIM) are widely employed in power systems comprising variable renewable energy-based electrical generation sources, such as wind farms and pumped-storage hydropower plants. However, their starting and grid synchronization methods require numerous maneuvers or additional components, making the process challenging. In this paper, a soft start method for DFIM, inspired by the traditional synchronization method of synchronous machines, is proposed. This method involves matching the frequencies, voltages, and phase angles on both sides of the main circuit breaker, by adjusting the excitation through the controlled power converter at standstill conditions. Once synchronization is achieved, the frequency is gradually reduced to the rated operational levels. This straightforward starting method effectively suppresses large inrush currents and voltage sags. The proposed method has been validated through computer simulations and experimental tests, yielding satisfactory results. ]]></content:encoded> <dc:title>A Soft Start Method for Doubly Fed Induction Machines Based on Synchronization with the Power System at Standstill Conditions</dc:title> <dc:creator>Jos茅 M. Guerrero</dc:creator> <dc:creator>Kumar Mahtani</dc:creator> <dc:creator>Itxaso Aranzabal</dc:creator> <dc:creator>Julen G贸mez-Cornejo</dc:creator> <dc:creator>Jos茅 A. S谩nchez</dc:creator> <dc:creator>Carlos A. Platero</dc:creator> <dc:identifier>doi: 10.3390/machines12120847</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-25</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-25</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Article</prism:section> <prism:startingPage>847</prism:startingPage> <prism:doi>10.3390/machines12120847</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/847</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/846"> <title>Machines, Vol. 12, Pages 846: Cross-Shaped Peg-in-Hole Autonomous Assembly System via BP Neural Network Based on Force/Moment and Visual Information</title> <link>https://www.mdpi.com/2075-1702/12/12/846</link> <description>Currently, research on peg-in-hole (PiH) compliant assembly is predominantly limited to circular pegs and holes, with insufficient exploration of various complex-shaped PiH tasks. Furthermore, the degree of freedom for rotation about the axis of the circular peg cannot be constrained after assembly, and few studies have covered the complete process from autonomous hole-searching to insertion. Based on the above problems, a novel cross-shaped peg and hole design has been devised. The center coordinates of the cross-hole are obtained during the hole-searching process using the three-dimensional reconstruction theory of a binocular stereo vision camera. During the insertion process, 26 contact states of the cross-peg and the cross-hole were classified, and the mapping relationship between the force-moment sensor and relative errors was established based on a backpropagation (BP) neural network, thus completing the task of autonomous PiH assembly. This system avoids hand-guiding, completely realizes the autonomous assembly task from hole-searching to insertion, and can be replaced by other structures of pegs and holes for repeated assembly after obtaining the accurate relative pose between two assembly platforms, which provides a brand-new and unified solution for complex-shaped PiH assembly.</description> <pubDate>2024-11-25</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 846: Cross-Shaped Peg-in-Hole Autonomous Assembly System via BP Neural Network Based on Force/Moment and Visual Information Machines <a href="https://www.mdpi.com/2075-1702/12/12/846">doi: 10.3390/machines12120846</a> Authors: Zheng Ma Xiaoguang Hu Yulin Zhou Currently, research on peg-in-hole (PiH) compliant assembly is predominantly limited to circular pegs and holes, with insufficient exploration of various complex-shaped PiH tasks. Furthermore, the degree of freedom for rotation about the axis of the circular peg cannot be constrained after assembly, and few studies have covered the complete process from autonomous hole-searching to insertion. Based on the above problems, a novel cross-shaped peg and hole design has been devised. The center coordinates of the cross-hole are obtained during the hole-searching process using the three-dimensional reconstruction theory of a binocular stereo vision camera. During the insertion process, 26 contact states of the cross-peg and the cross-hole were classified, and the mapping relationship between the force-moment sensor and relative errors was established based on a backpropagation (BP) neural network, thus completing the task of autonomous PiH assembly. This system avoids hand-guiding, completely realizes the autonomous assembly task from hole-searching to insertion, and can be replaced by other structures of pegs and holes for repeated assembly after obtaining the accurate relative pose between two assembly platforms, which provides a brand-new and unified solution for complex-shaped PiH assembly. ]]></content:encoded> <dc:title>Cross-Shaped Peg-in-Hole Autonomous Assembly System via BP Neural Network Based on Force/Moment and Visual Information</dc:title> <dc:creator>Zheng Ma</dc:creator> <dc:creator>Xiaoguang Hu</dc:creator> <dc:creator>Yulin Zhou</dc:creator> <dc:identifier>doi: 10.3390/machines12120846</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-25</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-25</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Article</prism:section> <prism:startingPage>846</prism:startingPage> <prism:doi>10.3390/machines12120846</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/846</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/845"> <title>Machines, Vol. 12, Pages 845: Review of Automated Operations in Drilling and Mining</title> <link>https://www.mdpi.com/2075-1702/12/12/845</link> <description>Current advances and trends in the fields of mechanical, material, and software engineering have allowed mining technology to undergo a significant transformation. Aiming to maximize the efficiency and safety of the mining process, several enabling technologies, such as the recent advances in artificial intelligence, IoT, sensor fusion, computational modeling, and advanced robotics, are being progressively adopted in mining machine manufacturing while replacing conventional parts and approaches that used to be the norm in the rock ore extraction industry. This article aims to provide an overview of research trends and state-of-the-art technologies in face exploration and drilling operations in order to define the vision toward the realization of fully autonomous mining exploration machines of the future, capable of operating without any external infrastructure. As the trend of mining at large depths is increasing and as the re-opening of abandoned mines is gaining more interest, near-to-face mining exploration approaches for identifying new ore bodies need to undergo significant revision. This article aims to contribute to future developments in the use of fully autonomous and cooperative smaller mining exploration machines.</description> <pubDate>2024-11-25</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 845: Review of Automated Operations in Drilling and Mining Machines <a href="https://www.mdpi.com/2075-1702/12/12/845">doi: 10.3390/machines12120845</a> Authors: Athanasios Kokkinis Theodore Frantzis Konstantinos Skordis George Nikolakopoulos Panagiotis Koustoumpardis Current advances and trends in the fields of mechanical, material, and software engineering have allowed mining technology to undergo a significant transformation. Aiming to maximize the efficiency and safety of the mining process, several enabling technologies, such as the recent advances in artificial intelligence, IoT, sensor fusion, computational modeling, and advanced robotics, are being progressively adopted in mining machine manufacturing while replacing conventional parts and approaches that used to be the norm in the rock ore extraction industry. This article aims to provide an overview of research trends and state-of-the-art technologies in face exploration and drilling operations in order to define the vision toward the realization of fully autonomous mining exploration machines of the future, capable of operating without any external infrastructure. As the trend of mining at large depths is increasing and as the re-opening of abandoned mines is gaining more interest, near-to-face mining exploration approaches for identifying new ore bodies need to undergo significant revision. This article aims to contribute to future developments in the use of fully autonomous and cooperative smaller mining exploration machines. ]]></content:encoded> <dc:title>Review of Automated Operations in Drilling and Mining</dc:title> <dc:creator>Athanasios Kokkinis</dc:creator> <dc:creator>Theodore Frantzis</dc:creator> <dc:creator>Konstantinos Skordis</dc:creator> <dc:creator>George Nikolakopoulos</dc:creator> <dc:creator>Panagiotis Koustoumpardis</dc:creator> <dc:identifier>doi: 10.3390/machines12120845</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-25</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-25</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Review</prism:section> <prism:startingPage>845</prism:startingPage> <prism:doi>10.3390/machines12120845</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/845</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/844"> <title>Machines, Vol. 12, Pages 844: Fault-Tolerant Closed-Loop Controller Using Online Fault Detection by Neural Networks</title> <link>https://www.mdpi.com/2075-1702/12/12/844</link> <description>This paper presents an online model-free sensor fault-tolerant control scheme capable of tolerating the most common faults affecting an induction motor. This approach involves using neural networks for fault detection to provide the controller with sufficient information to counteract adverse consequences due to sensor faults, such as degradation in performance, reliability, and even failures in the control system. The proposed approach does not consider the knowledge of the nominal model of the system or when the fault may occur. Therefore, a high-order recurrent neural network trained online by the Extended Kalman Filter is used to obtain a mathematical model of the system. The obtained model is used to synthesize a discrete-time sliding mode control. Then, the fault-detection and -isolation stage is performed by independent neural networks, which have as input the signal from the current sensor and the position sensor, respectively. In this way, the neural classifiers continuously monitor the sensors, showing the ability to know the sensor status. The combination of controller and fault detection maintains the operation of the motor during the time of the fault occurrence, whether due to sensor disconnection, degradation, or connection failure. In fact, the MLP neural network achieves an accuracy between 95% and 99% and shows an AUC of 97% to 99%, and this neural network correctly classifies true positives with acceptable performance. The Recall value is high, between 97% and 99%, and the F1 score confirms a good performance. In contrast, the CNN shows a higher accuracy, between 96% and 99% in accuracy and 98% to 99% in AUC. In addition, its Recall and F1 reflect a better balance and capacity to handle complex data, demonstrating its superiority to MLP in fault classification. Therefore, neural networks are a promising approach in areas such as fault-tolerant control.</description> <pubDate>2024-11-25</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 844: Fault-Tolerant Closed-Loop Controller Using Online Fault Detection by Neural Networks Machines <a href="https://www.mdpi.com/2075-1702/12/12/844">doi: 10.3390/machines12120844</a> Authors: Alma Y. Alanis Jesus G. Alvarez Oscar D. Sanchez Hannia M. Hernandez Arturo Valdivia-G This paper presents an online model-free sensor fault-tolerant control scheme capable of tolerating the most common faults affecting an induction motor. This approach involves using neural networks for fault detection to provide the controller with sufficient information to counteract adverse consequences due to sensor faults, such as degradation in performance, reliability, and even failures in the control system. The proposed approach does not consider the knowledge of the nominal model of the system or when the fault may occur. Therefore, a high-order recurrent neural network trained online by the Extended Kalman Filter is used to obtain a mathematical model of the system. The obtained model is used to synthesize a discrete-time sliding mode control. Then, the fault-detection and -isolation stage is performed by independent neural networks, which have as input the signal from the current sensor and the position sensor, respectively. In this way, the neural classifiers continuously monitor the sensors, showing the ability to know the sensor status. The combination of controller and fault detection maintains the operation of the motor during the time of the fault occurrence, whether due to sensor disconnection, degradation, or connection failure. In fact, the MLP neural network achieves an accuracy between 95% and 99% and shows an AUC of 97% to 99%, and this neural network correctly classifies true positives with acceptable performance. The Recall value is high, between 97% and 99%, and the F1 score confirms a good performance. In contrast, the CNN shows a higher accuracy, between 96% and 99% in accuracy and 98% to 99% in AUC. In addition, its Recall and F1 reflect a better balance and capacity to handle complex data, demonstrating its superiority to MLP in fault classification. Therefore, neural networks are a promising approach in areas such as fault-tolerant control. ]]></content:encoded> <dc:title>Fault-Tolerant Closed-Loop Controller Using Online Fault Detection by Neural Networks</dc:title> <dc:creator>Alma Y. Alanis</dc:creator> <dc:creator>Jesus G. Alvarez</dc:creator> <dc:creator>Oscar D. Sanchez</dc:creator> <dc:creator>Hannia M. Hernandez</dc:creator> <dc:creator>Arturo Valdivia-G</dc:creator> <dc:identifier>doi: 10.3390/machines12120844</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-25</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-25</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Article</prism:section> <prism:startingPage>844</prism:startingPage> <prism:doi>10.3390/machines12120844</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/844</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/843"> <title>Machines, Vol. 12, Pages 843: Detection of Damage on Inner and Outer Races of Ball Bearings Using a Low-Cost Monitoring System and Deep Convolution Neural Networks</title> <link>https://www.mdpi.com/2075-1702/12/12/843</link> <description>Bearings are vital components in machinery, and their malfunction can result in equipment damage and reduced productivity. As a result, considerable research attention has been directed toward the early detection of bearing faults. With recent rapid advancements in machine learning algorithms, there is increasing interest in proactively diagnosing bearing faults by analyzing signals obtained from bearings. Although numerous studies have introduced machine learning methods for bearing fault diagnosis, the high costs associated with sensors and data acquisition devices limit their practical application in industrial environments. Additionally, research aimed at identifying the root causes of faults through diagnostic algorithms has progressed relatively slowly. This study proposes a cost-effective monitoring system to improve economic feasibility. Its primary benefits include significant cost savings compared to traditional high-priced equipment, along with versatility and ease of installation, enabling straightforward attachment and removal. The system collects data by measuring the vibrations of both normal and faulty bearings under various operating conditions on a test bed. Using these data, a deep neural network is trained to enable real-time feature extraction and classification of bearing conditions. Furthermore, an explainable AI technique is applied to extract key feature values identified by the fault classification algorithm, providing a method to support the analysis of fault causes.</description> <pubDate>2024-11-25</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 843: Detection of Damage on Inner and Outer Races of Ball Bearings Using a Low-Cost Monitoring System and Deep Convolution Neural Networks Machines <a href="https://www.mdpi.com/2075-1702/12/12/843">doi: 10.3390/machines12120843</a> Authors: Handeul You Dongyeon Kim Juchan Kim Keunu Park Sangjin Maeng Bearings are vital components in machinery, and their malfunction can result in equipment damage and reduced productivity. As a result, considerable research attention has been directed toward the early detection of bearing faults. With recent rapid advancements in machine learning algorithms, there is increasing interest in proactively diagnosing bearing faults by analyzing signals obtained from bearings. Although numerous studies have introduced machine learning methods for bearing fault diagnosis, the high costs associated with sensors and data acquisition devices limit their practical application in industrial environments. Additionally, research aimed at identifying the root causes of faults through diagnostic algorithms has progressed relatively slowly. This study proposes a cost-effective monitoring system to improve economic feasibility. Its primary benefits include significant cost savings compared to traditional high-priced equipment, along with versatility and ease of installation, enabling straightforward attachment and removal. The system collects data by measuring the vibrations of both normal and faulty bearings under various operating conditions on a test bed. Using these data, a deep neural network is trained to enable real-time feature extraction and classification of bearing conditions. Furthermore, an explainable AI technique is applied to extract key feature values identified by the fault classification algorithm, providing a method to support the analysis of fault causes. ]]></content:encoded> <dc:title>Detection of Damage on Inner and Outer Races of Ball Bearings Using a Low-Cost Monitoring System and Deep Convolution Neural Networks</dc:title> <dc:creator>Handeul You</dc:creator> <dc:creator>Dongyeon Kim</dc:creator> <dc:creator>Juchan Kim</dc:creator> <dc:creator>Keunu Park</dc:creator> <dc:creator>Sangjin Maeng</dc:creator> <dc:identifier>doi: 10.3390/machines12120843</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-25</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-25</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Article</prism:section> <prism:startingPage>843</prism:startingPage> <prism:doi>10.3390/machines12120843</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/843</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/842"> <title>Machines, Vol. 12, Pages 842: Research on Unbalanced Vibration Characteristics and Assembly Phase Angle Probability Distribution of Dual-Rotor System</title> <link>https://www.mdpi.com/2075-1702/12/12/842</link> <description>This paper addresses the complex issue of vibration response characteristics resulting from the unbalanced assembly of the double rotors in the 31F aero-engine. The study investigates the vibration response behavior of the dual-rotor system through the adjustment of rotor assembly phase angle. Initially, a dynamic model of the four-disk, five-pivot dual-rotor system is established, with its natural frequencies and vibration modes verified. The influence of size and the position of the unbalance on the vibration amplitude in the dual-rotor system is analyzed. Additionally, the probability distribution of the assembly phase angles for both the compressor and turbine sections of the low-pressure rotor is examined. The results indicate that for the low-pressure rotor exhibiting excessive vibration, adjusting the assembly phase angle of the rotors&amp;rsquo; system&amp;rsquo;s compressor or the turbine section by 180 degrees leads to a vibration qualification rate of 70.1435%. This finding is consistent with the observations from the field experience method used in the former Soviet Union. Finally, corresponding experimental verification is conducted.</description> <pubDate>2024-11-24</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 842: Research on Unbalanced Vibration Characteristics and Assembly Phase Angle Probability Distribution of Dual-Rotor System Machines <a href="https://www.mdpi.com/2075-1702/12/12/842">doi: 10.3390/machines12120842</a> Authors: Hui Li Changzhi Shi Xuejun Li Mingfeng Li Jie Bian This paper addresses the complex issue of vibration response characteristics resulting from the unbalanced assembly of the double rotors in the 31F aero-engine. The study investigates the vibration response behavior of the dual-rotor system through the adjustment of rotor assembly phase angle. Initially, a dynamic model of the four-disk, five-pivot dual-rotor system is established, with its natural frequencies and vibration modes verified. The influence of size and the position of the unbalance on the vibration amplitude in the dual-rotor system is analyzed. Additionally, the probability distribution of the assembly phase angles for both the compressor and turbine sections of the low-pressure rotor is examined. The results indicate that for the low-pressure rotor exhibiting excessive vibration, adjusting the assembly phase angle of the rotors&amp;rsquo; system&amp;rsquo;s compressor or the turbine section by 180 degrees leads to a vibration qualification rate of 70.1435%. This finding is consistent with the observations from the field experience method used in the former Soviet Union. Finally, corresponding experimental verification is conducted. ]]></content:encoded> <dc:title>Research on Unbalanced Vibration Characteristics and Assembly Phase Angle Probability Distribution of Dual-Rotor System</dc:title> <dc:creator>Hui Li</dc:creator> <dc:creator>Changzhi Shi</dc:creator> <dc:creator>Xuejun Li</dc:creator> <dc:creator>Mingfeng Li</dc:creator> <dc:creator>Jie Bian</dc:creator> <dc:identifier>doi: 10.3390/machines12120842</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-24</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-24</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Article</prism:section> <prism:startingPage>842</prism:startingPage> <prism:doi>10.3390/machines12120842</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/842</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/841"> <title>Machines, Vol. 12, Pages 841: A Case Study on Assessing the Capability and Applicability of an Articulated Arm Coordinate Measuring Machine and a Touch-Trigger Probe for On-Machine Measurement</title> <link>https://www.mdpi.com/2075-1702/12/12/841</link> <description>In modern manufacturing, there is an increasing demand for reliable in-process measurement methods directly on large CNC machine tools, eliminating the need to transport workpieces to metrological laboratories. This study assesses the capability and applicability of an articulated arm coordinate measuring machine and a machine tool touch-trigger probe when measuring to a specified tolerance of 0.05 mm in a production environment. Experiments were conducted using the KOBA calibration standard and included measurements with and without applying the articulated arm coordinate measuring machine leapfrog method. The results were evaluated according to ISO 22514-7:2021 and ISO 14253-1:2017, which establish criteria for measurement system capability. The findings revealed that neither measurement system met the capability requirements of ISO 22514-7:2021, particularly due to unsatisfactory QMS and CMS values. However, under ISO 14253-1:2017, both systems were deemed conditionally suitable for verifying conformity to the specifications, with the articulated arm coordinate measuring machine showing lower applicability when using the leapfrog method. This research supports the idea that unreasonable demands for compliance with current standards may lead to questioning of the systems that previously met older standards. The study contributes to the ongoing discussion on integrating advanced metrological tools into the manufacturing process and underscores the need for careful evaluation to ensure the capability and reliability of measurement systems in industrial practice.</description> <pubDate>2024-11-23</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 841: A Case Study on Assessing the Capability and Applicability of an Articulated Arm Coordinate Measuring Machine and a Touch-Trigger Probe for On-Machine Measurement Machines <a href="https://www.mdpi.com/2075-1702/12/12/841">doi: 10.3390/machines12120841</a> Authors: Vendula Samelova Tomas Marek Adam Jelinek Robert Jankovych Karla Maradova Michal Holub In modern manufacturing, there is an increasing demand for reliable in-process measurement methods directly on large CNC machine tools, eliminating the need to transport workpieces to metrological laboratories. This study assesses the capability and applicability of an articulated arm coordinate measuring machine and a machine tool touch-trigger probe when measuring to a specified tolerance of 0.05 mm in a production environment. Experiments were conducted using the KOBA calibration standard and included measurements with and without applying the articulated arm coordinate measuring machine leapfrog method. The results were evaluated according to ISO 22514-7:2021 and ISO 14253-1:2017, which establish criteria for measurement system capability. The findings revealed that neither measurement system met the capability requirements of ISO 22514-7:2021, particularly due to unsatisfactory QMS and CMS values. However, under ISO 14253-1:2017, both systems were deemed conditionally suitable for verifying conformity to the specifications, with the articulated arm coordinate measuring machine showing lower applicability when using the leapfrog method. This research supports the idea that unreasonable demands for compliance with current standards may lead to questioning of the systems that previously met older standards. The study contributes to the ongoing discussion on integrating advanced metrological tools into the manufacturing process and underscores the need for careful evaluation to ensure the capability and reliability of measurement systems in industrial practice. ]]></content:encoded> <dc:title>A Case Study on Assessing the Capability and Applicability of an Articulated Arm Coordinate Measuring Machine and a Touch-Trigger Probe for On-Machine Measurement</dc:title> <dc:creator>Vendula Samelova</dc:creator> <dc:creator>Tomas Marek</dc:creator> <dc:creator>Adam Jelinek</dc:creator> <dc:creator>Robert Jankovych</dc:creator> <dc:creator>Karla Maradova</dc:creator> <dc:creator>Michal Holub</dc:creator> <dc:identifier>doi: 10.3390/machines12120841</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-23</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-23</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Article</prism:section> <prism:startingPage>841</prism:startingPage> <prism:doi>10.3390/machines12120841</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/841</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/840"> <title>Machines, Vol. 12, Pages 840: Use of Image Recognition and Machine Learning for the Automatic and Objective Evaluation of Standstill Marks on Rolling Bearings</title> <link>https://www.mdpi.com/2075-1702/12/12/840</link> <description>One main research area of the Competence Centre for Tribology is so-called standstill marks (SSMs) at roller bearings that occur if the bearing is exposed to vibrations or performs just micromovements. SSMs obtained from experiments are usually photographed, evaluated and manually categorized into six classes. An internal project has now investigated the extent to which this evaluation can be automated and objectified. Images of standstill marks were classified using convolutional neural networks that were implemented with the deep learning library Pytorch. With basic convolutional neural networks, an accuracy of 70.19% for the classification of all six classes and 83.65% for the classification of pairwise classes was achieved. Classification accuracies were improved by image augmentation and transfer learning with pre-trained convolutional neural networks. Overall, an accuracy of 83.65% for the classification of all six standstill mark classes and 91.35% for the classification of pairwise classes was achieved. Since 16 individual marks are generated per test run in a typical quasi standstill test (QSST) of the CCT and the deviation in the prediction of the classification is a maximum of one school grade, the accuracy achieved is already sufficient to carry out a reliable and objective evaluation of the markings.</description> <pubDate>2024-11-23</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 840: Use of Image Recognition and Machine Learning for the Automatic and Objective Evaluation of Standstill Marks on Rolling Bearings Machines <a href="https://www.mdpi.com/2075-1702/12/12/840">doi: 10.3390/machines12120840</a> Authors: Markus Grebe Alexander Baral Dominik Martin One main research area of the Competence Centre for Tribology is so-called standstill marks (SSMs) at roller bearings that occur if the bearing is exposed to vibrations or performs just micromovements. SSMs obtained from experiments are usually photographed, evaluated and manually categorized into six classes. An internal project has now investigated the extent to which this evaluation can be automated and objectified. Images of standstill marks were classified using convolutional neural networks that were implemented with the deep learning library Pytorch. With basic convolutional neural networks, an accuracy of 70.19% for the classification of all six classes and 83.65% for the classification of pairwise classes was achieved. Classification accuracies were improved by image augmentation and transfer learning with pre-trained convolutional neural networks. Overall, an accuracy of 83.65% for the classification of all six standstill mark classes and 91.35% for the classification of pairwise classes was achieved. Since 16 individual marks are generated per test run in a typical quasi standstill test (QSST) of the CCT and the deviation in the prediction of the classification is a maximum of one school grade, the accuracy achieved is already sufficient to carry out a reliable and objective evaluation of the markings. ]]></content:encoded> <dc:title>Use of Image Recognition and Machine Learning for the Automatic and Objective Evaluation of Standstill Marks on Rolling Bearings</dc:title> <dc:creator>Markus Grebe</dc:creator> <dc:creator>Alexander Baral</dc:creator> <dc:creator>Dominik Martin</dc:creator> <dc:identifier>doi: 10.3390/machines12120840</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-23</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-23</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Article</prism:section> <prism:startingPage>840</prism:startingPage> <prism:doi>10.3390/machines12120840</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/840</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/839"> <title>Machines, Vol. 12, Pages 839: Overview of IoT Security Challenges and Sensors Specifications in PMSM for Elevator Applications</title> <link>https://www.mdpi.com/2075-1702/12/12/839</link> <description>The applications of the permanent magnet synchronous motor (PMSM) are the most seen in the elevator industry due to their high efficiency, low losses and the potential for high energy savings. The Internet of Things (IoT) is a modern technology which is being incorporated in various industrial applications, especially in electrical machines as a means of control, monitoring and preventive maintenance. This paper is focused on reviewing the use PMSM in lift systems, the application of various condition monitoring techniques and real-time data collection techniques using IoT technology. In addition, we focus on different categories of industrial sensors, their connectivity and the standards they should meet for PMSMs used in elevator applications. Finally, we analyze various secure ways of transmitting data on different platforms so that the transmission of information takes into account possible unwanted instructions from exogenous factors.</description> <pubDate>2024-11-22</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 839: Overview of IoT Security Challenges and Sensors Specifications in PMSM for Elevator Applications Machines <a href="https://www.mdpi.com/2075-1702/12/12/839">doi: 10.3390/machines12120839</a> Authors: Eftychios I. Vlachou Vasileios I. Vlachou Dimitrios E. Efstathiou Theoklitos S. Karakatsanis The applications of the permanent magnet synchronous motor (PMSM) are the most seen in the elevator industry due to their high efficiency, low losses and the potential for high energy savings. The Internet of Things (IoT) is a modern technology which is being incorporated in various industrial applications, especially in electrical machines as a means of control, monitoring and preventive maintenance. This paper is focused on reviewing the use PMSM in lift systems, the application of various condition monitoring techniques and real-time data collection techniques using IoT technology. In addition, we focus on different categories of industrial sensors, their connectivity and the standards they should meet for PMSMs used in elevator applications. Finally, we analyze various secure ways of transmitting data on different platforms so that the transmission of information takes into account possible unwanted instructions from exogenous factors. ]]></content:encoded> <dc:title>Overview of IoT Security Challenges and Sensors Specifications in PMSM for Elevator Applications</dc:title> <dc:creator>Eftychios I. Vlachou</dc:creator> <dc:creator>Vasileios I. Vlachou</dc:creator> <dc:creator>Dimitrios E. Efstathiou</dc:creator> <dc:creator>Theoklitos S. Karakatsanis</dc:creator> <dc:identifier>doi: 10.3390/machines12120839</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-22</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-22</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Review</prism:section> <prism:startingPage>839</prism:startingPage> <prism:doi>10.3390/machines12120839</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/839</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/838"> <title>Machines, Vol. 12, Pages 838: Prior Knowledge-Informed Graph Neural Network with Multi-Source Data-Weighted Fusion for Intelligent Bogie Fault Diagnosis</title> <link>https://www.mdpi.com/2075-1702/12/12/838</link> <description>The current multi-source fusion fault diagnosis algorithm rarely considers the information correlation of multi-sensor networks and the important difference between multi-sensors. Aiming at this challenge, we propose an intelligent fault identification method for high-speed railway bogie based on the graph neural network embedded with prior knowledge, which brings the spatial information of the sensor network into the diagnosis algorithm and re-weights each sensor according to the diagnosis results. Firstly, the time&amp;ndash;domain correlation of vibration signals between bogie sensor networks is calculated as the prior knowledge. Then, based on the spatial topological relationship of the sensors, the graph correlation matrix of the network is established. Further, the importance of each sensor is dynamically analyzed and updated together with the training process. The proposed method is tested on a high-precision bogie test bed, and the experimental results demonstrate the effectiveness and superiority of the proposed method.</description> <pubDate>2024-11-22</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 838: Prior Knowledge-Informed Graph Neural Network with Multi-Source Data-Weighted Fusion for Intelligent Bogie Fault Diagnosis Machines <a href="https://www.mdpi.com/2075-1702/12/12/838">doi: 10.3390/machines12120838</a> Authors: Yuanxing Huang Bofeng Cui Xianqun Mao Jinsong Yang The current multi-source fusion fault diagnosis algorithm rarely considers the information correlation of multi-sensor networks and the important difference between multi-sensors. Aiming at this challenge, we propose an intelligent fault identification method for high-speed railway bogie based on the graph neural network embedded with prior knowledge, which brings the spatial information of the sensor network into the diagnosis algorithm and re-weights each sensor according to the diagnosis results. Firstly, the time&amp;ndash;domain correlation of vibration signals between bogie sensor networks is calculated as the prior knowledge. Then, based on the spatial topological relationship of the sensors, the graph correlation matrix of the network is established. Further, the importance of each sensor is dynamically analyzed and updated together with the training process. The proposed method is tested on a high-precision bogie test bed, and the experimental results demonstrate the effectiveness and superiority of the proposed method. ]]></content:encoded> <dc:title>Prior Knowledge-Informed Graph Neural Network with Multi-Source Data-Weighted Fusion for Intelligent Bogie Fault Diagnosis</dc:title> <dc:creator>Yuanxing Huang</dc:creator> <dc:creator>Bofeng Cui</dc:creator> <dc:creator>Xianqun Mao</dc:creator> <dc:creator>Jinsong Yang</dc:creator> <dc:identifier>doi: 10.3390/machines12120838</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-22</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-22</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Article</prism:section> <prism:startingPage>838</prism:startingPage> <prism:doi>10.3390/machines12120838</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/838</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/837"> <title>Machines, Vol. 12, Pages 837: Design and Rapid Prototyping of Deformable Rotors for Amphibious Navigation in Water and Air</title> <link>https://www.mdpi.com/2075-1702/12/12/837</link> <description>This paper aims to report the design of a mechanism to drive a propeller to deform between an aerial and one aquatic shape. This mechanism can realize the deformation of blade angle, radius, blade twist angle distribution and blade section thickness. Inspired by the Kresling origami structure and utilizing its rotation-folding motion characteristics, a propeller hub structure with variable blade angle is designed. A blade deformation unit (S-unit) with extensional-torsional kinematic characteristics is designed through the motion analysis of a spherical four-bar mechanism. A rib support structure fixed to the linkages of the s-unit is designed to achieve the change in blade section thickness. Based on motion analysis, the coordinate transformation method has been used to establish the relationship between propeller shape and deformation mechanism. The deformation of blade extension, blade twist distribution, and blade section thickness are analyzed. The deformation ability of the proposed structure can be verified then by kinematic simulation and rapid prototyping based on 3-D printing. It is proved that the proposed mechanism is applicable to deformable propeller design. The rapid prototype testing validates the stable motion of the mechanism. However, due to the relatively large self-weight of the structure, the blade has a slight deformation. In the subsequent work, the structural strength issue needs to be emphasized.</description> <pubDate>2024-11-22</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 837: Design and Rapid Prototyping of Deformable Rotors for Amphibious Navigation in Water and Air Machines <a href="https://www.mdpi.com/2075-1702/12/12/837">doi: 10.3390/machines12120837</a> Authors: Chengrong Du Dongbiao Zhao This paper aims to report the design of a mechanism to drive a propeller to deform between an aerial and one aquatic shape. This mechanism can realize the deformation of blade angle, radius, blade twist angle distribution and blade section thickness. Inspired by the Kresling origami structure and utilizing its rotation-folding motion characteristics, a propeller hub structure with variable blade angle is designed. A blade deformation unit (S-unit) with extensional-torsional kinematic characteristics is designed through the motion analysis of a spherical four-bar mechanism. A rib support structure fixed to the linkages of the s-unit is designed to achieve the change in blade section thickness. Based on motion analysis, the coordinate transformation method has been used to establish the relationship between propeller shape and deformation mechanism. The deformation of blade extension, blade twist distribution, and blade section thickness are analyzed. The deformation ability of the proposed structure can be verified then by kinematic simulation and rapid prototyping based on 3-D printing. It is proved that the proposed mechanism is applicable to deformable propeller design. The rapid prototype testing validates the stable motion of the mechanism. However, due to the relatively large self-weight of the structure, the blade has a slight deformation. In the subsequent work, the structural strength issue needs to be emphasized. ]]></content:encoded> <dc:title>Design and Rapid Prototyping of Deformable Rotors for Amphibious Navigation in Water and Air</dc:title> <dc:creator>Chengrong Du</dc:creator> <dc:creator>Dongbiao Zhao</dc:creator> <dc:identifier>doi: 10.3390/machines12120837</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-22</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-22</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Article</prism:section> <prism:startingPage>837</prism:startingPage> <prism:doi>10.3390/machines12120837</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/837</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/836"> <title>Machines, Vol. 12, Pages 836: A Data-Driven-Based Grounding Fault Location Method for the Auxiliary Power Supply System in an Electric Locomotive</title> <link>https://www.mdpi.com/2075-1702/12/12/836</link> <description>Grounding faults are a common type of fault in train auxiliary power supply systems (APS). Timely identification and localization of these faults are crucial for ensuring the stable operation of electric locomotives and the safety of passengers. Therefore, this paper proposes a fault diagnosis method for grounding faults (GFs) that integrates mechanistic insights with data-driven feature extraction. Firstly, this paper analyzes the mechanisms of grounding faults and summarizes the characteristics of their time&amp;ndash;frequency distribution. Then, a Short-Time Fourier Transform (STFT) is employed to derive a frequency signature vector enabling classification into three principal categories. Concurrently, a time series sliding window approach is applied to extract time domain indicators for further subdivision of fault types. Finally, a time&amp;ndash;frequency hybrid-driven diagnostic model framework is constructed by integrating the frequency distribution with the spatiotemporal map, and validation is conducted using an experimental platform that replicates system fault scenarios with a hardware-in-the-loop (HIL) simulation and executes the real-time diagnostic frameworks on a DSP diagnostic board card. The results demonstrate that the proposed method can detect and accurately locate grounding faults in real time.</description> <pubDate>2024-11-22</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 836: A Data-Driven-Based Grounding Fault Location Method for the Auxiliary Power Supply System in an Electric Locomotive Machines <a href="https://www.mdpi.com/2075-1702/12/12/836">doi: 10.3390/machines12120836</a> Authors: Xinyao Hou Yang Meng Qiang Ni Grounding faults are a common type of fault in train auxiliary power supply systems (APS). Timely identification and localization of these faults are crucial for ensuring the stable operation of electric locomotives and the safety of passengers. Therefore, this paper proposes a fault diagnosis method for grounding faults (GFs) that integrates mechanistic insights with data-driven feature extraction. Firstly, this paper analyzes the mechanisms of grounding faults and summarizes the characteristics of their time&amp;ndash;frequency distribution. Then, a Short-Time Fourier Transform (STFT) is employed to derive a frequency signature vector enabling classification into three principal categories. Concurrently, a time series sliding window approach is applied to extract time domain indicators for further subdivision of fault types. Finally, a time&amp;ndash;frequency hybrid-driven diagnostic model framework is constructed by integrating the frequency distribution with the spatiotemporal map, and validation is conducted using an experimental platform that replicates system fault scenarios with a hardware-in-the-loop (HIL) simulation and executes the real-time diagnostic frameworks on a DSP diagnostic board card. The results demonstrate that the proposed method can detect and accurately locate grounding faults in real time. ]]></content:encoded> <dc:title>A Data-Driven-Based Grounding Fault Location Method for the Auxiliary Power Supply System in an Electric Locomotive</dc:title> <dc:creator>Xinyao Hou</dc:creator> <dc:creator>Yang Meng</dc:creator> <dc:creator>Qiang Ni</dc:creator> <dc:identifier>doi: 10.3390/machines12120836</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-22</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-22</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Article</prism:section> <prism:startingPage>836</prism:startingPage> <prism:doi>10.3390/machines12120836</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/836</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/835"> <title>Machines, Vol. 12, Pages 835: Design and Simulation of Portable Paving Vehicle for Straw Checkerboard Barriers</title> <link>https://www.mdpi.com/2075-1702/12/12/835</link> <description>Paving straw checkerboard barriers in the desert is an efficient measure of wind break and sand fixation. Generally, straw checkerboard barriers are paved manually. Focusing on the low automation level of straw checkerboard barrier paving, a portable paving vehicle for straw checkerboard barriers was designed in this paper. First, the portable paving vehicle for straw checkerboard barriers was designed using SolidWorks, and the design contents include a grass insertion mechanism, an intermittent transmission mechanism, a metamorphic mechanism, and motor and power supply. Then, the load test of the grass insertion mechanism was carried out to determine the maximum force load of 25 N during the grass insertion process, and the strength of the rocker and the horizontal slide rod were checked. Among them, the safety factor of the rocker rod and the horizontal slide rod were 1 and 1.5, respectively, and the allowable stress of the rocker rod and the horizontal slide rod was 27.3 MPa and 205 MPa. The maximum stresses of 0.92 MPa and 67 MPa were less than the allowable stresses, which meet the strength requirements. In order to verify the design principle and the results of the strength check, the grass insertion mechanism, rocker, and horizontal slide rod were analyzed by using ABAQUS. The results show that the grass insertion mechanism has an obvious rapid return characteristic, which is in agreement with the design principle. At the same time, the maximum stress of the rocker rod and the horizontal slide rod was 1 MPa and 36 MPa, respectively, which meets the strength requirements. Finally, the physical prototype was manufactured and its running state was verified. The results show that the physical prototype can pave the straw checkerboard sand barrier on the sand normally, and the portable paving vehicle for straw checkerboard barriers can be a reference for other sand-control vehicles and provide an effective way of paving straw checkerboard barriers to control desertification.</description> <pubDate>2024-11-22</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 835: Design and Simulation of Portable Paving Vehicle for Straw Checkerboard Barriers Machines <a href="https://www.mdpi.com/2075-1702/12/12/835">doi: 10.3390/machines12120835</a> Authors: Zuntao Peng Mingrun Jia Jingrong Fang Feng Jiang Paving straw checkerboard barriers in the desert is an efficient measure of wind break and sand fixation. Generally, straw checkerboard barriers are paved manually. Focusing on the low automation level of straw checkerboard barrier paving, a portable paving vehicle for straw checkerboard barriers was designed in this paper. First, the portable paving vehicle for straw checkerboard barriers was designed using SolidWorks, and the design contents include a grass insertion mechanism, an intermittent transmission mechanism, a metamorphic mechanism, and motor and power supply. Then, the load test of the grass insertion mechanism was carried out to determine the maximum force load of 25 N during the grass insertion process, and the strength of the rocker and the horizontal slide rod were checked. Among them, the safety factor of the rocker rod and the horizontal slide rod were 1 and 1.5, respectively, and the allowable stress of the rocker rod and the horizontal slide rod was 27.3 MPa and 205 MPa. The maximum stresses of 0.92 MPa and 67 MPa were less than the allowable stresses, which meet the strength requirements. In order to verify the design principle and the results of the strength check, the grass insertion mechanism, rocker, and horizontal slide rod were analyzed by using ABAQUS. The results show that the grass insertion mechanism has an obvious rapid return characteristic, which is in agreement with the design principle. At the same time, the maximum stress of the rocker rod and the horizontal slide rod was 1 MPa and 36 MPa, respectively, which meets the strength requirements. Finally, the physical prototype was manufactured and its running state was verified. The results show that the physical prototype can pave the straw checkerboard sand barrier on the sand normally, and the portable paving vehicle for straw checkerboard barriers can be a reference for other sand-control vehicles and provide an effective way of paving straw checkerboard barriers to control desertification. ]]></content:encoded> <dc:title>Design and Simulation of Portable Paving Vehicle for Straw Checkerboard Barriers</dc:title> <dc:creator>Zuntao Peng</dc:creator> <dc:creator>Mingrun Jia</dc:creator> <dc:creator>Jingrong Fang</dc:creator> <dc:creator>Feng Jiang</dc:creator> <dc:identifier>doi: 10.3390/machines12120835</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-22</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-22</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Article</prism:section> <prism:startingPage>835</prism:startingPage> <prism:doi>10.3390/machines12120835</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/835</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/834"> <title>Machines, Vol. 12, Pages 834: A Five-Axis Toolpath Corner-Smoothing Method Based on the Space of Master&ndash;Slave Movement</title> <link>https://www.mdpi.com/2075-1702/12/12/834</link> <description>The smoothing of linear toolpaths plays is critical in improving machining quality and efficiency in five-axis CNC machining. Existing corner-smoothing methods often overlook the impact of spline curvature fluctuations, which may lead to acceleration variations, hindering surface quality improvements. The paper presents a five-axis toolpath corner-smoothing method based on the space of master&amp;ndash;slave movement (SMM), aiming to minimize curvature fluctuations in five-axis machining and improve surface quality. The concept of movement space in master&amp;ndash;slave cooperative motion is introduced, where the tool tip position and tool orientation are decoupled into a main motion trajectory and two master&amp;ndash;slave movement space trajectories. By deriving the curvature monotony conditions of a dual B&amp;eacute;zier spline, a G2-continuous tool tip corner-smoothing curve with minimal curvature fluctuations is constructed in real-time. Subsequently, using the SMM and the asymmetric dual B&amp;eacute;zier spline, a high-order continuous synchronization relationship between the tool tip position and tool orientation is established. Simulation tests and machining experiments show that with our smoothing algorithm, maximum acceleration values for each axis were reduced by 21.05%, while jerk was lowered by 22.31%. These results indicate that trajectory smoothing significantly reduces mechanical vibrations and improves surface quality.</description> <pubDate>2024-11-21</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 834: A Five-Axis Toolpath Corner-Smoothing Method Based on the Space of Master&ndash;Slave Movement Machines <a href="https://www.mdpi.com/2075-1702/12/12/834">doi: 10.3390/machines12120834</a> Authors: Song Gao Haiming Zhang Jianzhong Yang Jiejun Xie Wanqiang Zhu The smoothing of linear toolpaths plays is critical in improving machining quality and efficiency in five-axis CNC machining. Existing corner-smoothing methods often overlook the impact of spline curvature fluctuations, which may lead to acceleration variations, hindering surface quality improvements. The paper presents a five-axis toolpath corner-smoothing method based on the space of master&amp;ndash;slave movement (SMM), aiming to minimize curvature fluctuations in five-axis machining and improve surface quality. The concept of movement space in master&amp;ndash;slave cooperative motion is introduced, where the tool tip position and tool orientation are decoupled into a main motion trajectory and two master&amp;ndash;slave movement space trajectories. By deriving the curvature monotony conditions of a dual B&amp;eacute;zier spline, a G2-continuous tool tip corner-smoothing curve with minimal curvature fluctuations is constructed in real-time. Subsequently, using the SMM and the asymmetric dual B&amp;eacute;zier spline, a high-order continuous synchronization relationship between the tool tip position and tool orientation is established. Simulation tests and machining experiments show that with our smoothing algorithm, maximum acceleration values for each axis were reduced by 21.05%, while jerk was lowered by 22.31%. These results indicate that trajectory smoothing significantly reduces mechanical vibrations and improves surface quality. ]]></content:encoded> <dc:title>A Five-Axis Toolpath Corner-Smoothing Method Based on the Space of Master&amp;ndash;Slave Movement</dc:title> <dc:creator>Song Gao</dc:creator> <dc:creator>Haiming Zhang</dc:creator> <dc:creator>Jianzhong Yang</dc:creator> <dc:creator>Jiejun Xie</dc:creator> <dc:creator>Wanqiang Zhu</dc:creator> <dc:identifier>doi: 10.3390/machines12120834</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-21</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-21</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Article</prism:section> <prism:startingPage>834</prism:startingPage> <prism:doi>10.3390/machines12120834</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/834</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/833"> <title>Machines, Vol. 12, Pages 833: A Review of Physics-Based, Data-Driven, and Hybrid Models for Tool Wear Monitoring</title> <link>https://www.mdpi.com/2075-1702/12/12/833</link> <description>Tool wear is an inevitable phenomenon in the machining process. By monitoring the wear state of a tool, the machining system can give early warning and make advance decisions, which effectively ensures improved machining quality and production efficiency. In the past two decades, scholars have conducted extensive research on tool wear monitoring (TWM) and obtained a series of remarkable research achievements. However, physics-based models have difficulty predicting tool wear accurately. Meanwhile, the diversity of actual machining environments further limits the application of physical models. Data-driven models can establish the deep mapping relationship between signals and tool wear, but they only fit trained data well. They still have difficulty adapting to complex machining conditions. In this paper, physics-based and data-driven TWM models are first reviewed in detail, including the factors that affect tool wear, typical data-based models, and methods for extracting and selecting features. Then, tracking research hotspots, emerging physics&amp;ndash;data fusion models are systematically summarized.</description> <pubDate>2024-11-21</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 833: A Review of Physics-Based, Data-Driven, and Hybrid Models for Tool Wear Monitoring Machines <a href="https://www.mdpi.com/2075-1702/12/12/833">doi: 10.3390/machines12120833</a> Authors: Haoyuan Zhang Shanglei Jiang Defeng Gao Yuwen Sun Wenxiang Bai Tool wear is an inevitable phenomenon in the machining process. By monitoring the wear state of a tool, the machining system can give early warning and make advance decisions, which effectively ensures improved machining quality and production efficiency. In the past two decades, scholars have conducted extensive research on tool wear monitoring (TWM) and obtained a series of remarkable research achievements. However, physics-based models have difficulty predicting tool wear accurately. Meanwhile, the diversity of actual machining environments further limits the application of physical models. Data-driven models can establish the deep mapping relationship between signals and tool wear, but they only fit trained data well. They still have difficulty adapting to complex machining conditions. In this paper, physics-based and data-driven TWM models are first reviewed in detail, including the factors that affect tool wear, typical data-based models, and methods for extracting and selecting features. Then, tracking research hotspots, emerging physics&amp;ndash;data fusion models are systematically summarized. ]]></content:encoded> <dc:title>A Review of Physics-Based, Data-Driven, and Hybrid Models for Tool Wear Monitoring</dc:title> <dc:creator>Haoyuan Zhang</dc:creator> <dc:creator>Shanglei Jiang</dc:creator> <dc:creator>Defeng Gao</dc:creator> <dc:creator>Yuwen Sun</dc:creator> <dc:creator>Wenxiang Bai</dc:creator> <dc:identifier>doi: 10.3390/machines12120833</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-21</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-21</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Review</prism:section> <prism:startingPage>833</prism:startingPage> <prism:doi>10.3390/machines12120833</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/833</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/832"> <title>Machines, Vol. 12, Pages 832: Incipient Fault Detection and Recognition of China Railway High-Speed (CRH) Suspension System Based on Probabilistic Relevant Principal Component Analysis (PRPCA) and Support Vector Machine (SVM)</title> <link>https://www.mdpi.com/2075-1702/12/12/832</link> <description>As a crucial component of CRH (China Railway High-speed) trains, the safety and stability of the suspension system are of paramount importance to the overall vehicle system. Based on the framework of probabilistic relevant principal component analysis (PRPCA), this paper proposes a novel method for incipient fault diagnosis in the CRH suspension system using PRPCA and support vector machine (SVM). Firstly, simulation data containing multiple types of fault information are obtained from the Simpack2018.1-Matlab2016a/Simulink co-simulation platform. Secondly, the nonlinear PRPCA approach, based on the Wasserstein distance, is employed for fault detection and data preprocessing in the suspension system. Furthermore, SVM is used for fault recognition, and the F1-Measure index is utilized for a comprehensive evaluation to assess the fault diagnosis performance more intuitively. Finally, based on the comparison results with traditional principal component analysis (PCA) and SVM-based methods, the proposed incipient fault diagnosis method demonstrates superior efficiency in fault detection and recognition. However, the proposed method is not very sensitive to sensor faults, and the performance of sensor fault diagnosis needs to be further improved in subsequent research.</description> <pubDate>2024-11-21</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 832: Incipient Fault Detection and Recognition of China Railway High-Speed (CRH) Suspension System Based on Probabilistic Relevant Principal Component Analysis (PRPCA) and Support Vector Machine (SVM) Machines <a href="https://www.mdpi.com/2075-1702/12/12/832">doi: 10.3390/machines12120832</a> Authors: Kang Feng Yunkai Wu Yang Zhou Yijin Zhou As a crucial component of CRH (China Railway High-speed) trains, the safety and stability of the suspension system are of paramount importance to the overall vehicle system. Based on the framework of probabilistic relevant principal component analysis (PRPCA), this paper proposes a novel method for incipient fault diagnosis in the CRH suspension system using PRPCA and support vector machine (SVM). Firstly, simulation data containing multiple types of fault information are obtained from the Simpack2018.1-Matlab2016a/Simulink co-simulation platform. Secondly, the nonlinear PRPCA approach, based on the Wasserstein distance, is employed for fault detection and data preprocessing in the suspension system. Furthermore, SVM is used for fault recognition, and the F1-Measure index is utilized for a comprehensive evaluation to assess the fault diagnosis performance more intuitively. Finally, based on the comparison results with traditional principal component analysis (PCA) and SVM-based methods, the proposed incipient fault diagnosis method demonstrates superior efficiency in fault detection and recognition. However, the proposed method is not very sensitive to sensor faults, and the performance of sensor fault diagnosis needs to be further improved in subsequent research. ]]></content:encoded> <dc:title>Incipient Fault Detection and Recognition of China Railway High-Speed (CRH) Suspension System Based on Probabilistic Relevant Principal Component Analysis (PRPCA) and Support Vector Machine (SVM)</dc:title> <dc:creator>Kang Feng</dc:creator> <dc:creator>Yunkai Wu</dc:creator> <dc:creator>Yang Zhou</dc:creator> <dc:creator>Yijin Zhou</dc:creator> <dc:identifier>doi: 10.3390/machines12120832</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-21</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-21</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Article</prism:section> <prism:startingPage>832</prism:startingPage> <prism:doi>10.3390/machines12120832</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/832</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/830"> <title>Machines, Vol. 12, Pages 830: Correction: Montgomery-Smith, S.; Shy, C. Using Lie Derivatives with Dual Quaternions for Parallel Robots. Machines 2023, 11, 1056</title> <link>https://www.mdpi.com/2075-1702/12/12/830</link> <description>In the published paper [...]</description> <pubDate>2024-11-21</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 830: Correction: Montgomery-Smith, S.; Shy, C. Using Lie Derivatives with Dual Quaternions for Parallel Robots. Machines 2023, 11, 1056 Machines <a href="https://www.mdpi.com/2075-1702/12/12/830">doi: 10.3390/machines12120830</a> Authors: Stephen Montgomery-Smith Cecil Shy In the published paper [...] ]]></content:encoded> <dc:title>Correction: Montgomery-Smith, S.; Shy, C. Using Lie Derivatives with Dual Quaternions for Parallel Robots. Machines 2023, 11, 1056</dc:title> <dc:creator>Stephen Montgomery-Smith</dc:creator> <dc:creator>Cecil Shy</dc:creator> <dc:identifier>doi: 10.3390/machines12120830</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-21</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-21</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Correction</prism:section> <prism:startingPage>830</prism:startingPage> <prism:doi>10.3390/machines12120830</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/830</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/831"> <title>Machines, Vol. 12, Pages 831: Fault Detection in Harmonic Drive Using Multi-Sensor Data Fusion and Gravitational Search Algorithm</title> <link>https://www.mdpi.com/2075-1702/12/12/831</link> <description>This study proposes a fault diagnosis method for harmonic drive systems based on multi-sensor data fusion and the gravitational search algorithm (GSA). As a critical component in robotic arms, harmonic drives are prone to failures due to wear, less grease, or improper loading, which can compromise system stability and production efficiency. To enhance diagnostic accuracy, the research employs wavelet packet decomposition (WPD) and empirical mode decomposition (EMD) to extract multi-scale features from vibration signals. These features are subsequently fused, and GSA is used to optimize the high-dimensional fused features, eliminating redundant data and mitigating overfitting. The optimized features are then input into a support vector machine (SVM) for fault classification, with K-fold cross-validation used to assess the model&amp;rsquo;s generalization capabilities. Experimental results demonstrate that the proposed diagnosis method, which integrates multi-sensor data fusion with GSA optimization, significantly improves fault diagnosis accuracy compared to methods using single-sensor signals or unoptimized features. This improvement is particularly notable in multi-class fault scenarios. Additionally, GSA&amp;rsquo;s global search capability effectively addresses overfitting issues caused by high-dimensional data, resulting in a diagnostic model with greater reliability and accuracy across various fault conditions.</description> <pubDate>2024-11-21</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 831: Fault Detection in Harmonic Drive Using Multi-Sensor Data Fusion and Gravitational Search Algorithm Machines <a href="https://www.mdpi.com/2075-1702/12/12/831">doi: 10.3390/machines12120831</a> Authors: Nan-Kai Hsieh Tsung-Yu Yu This study proposes a fault diagnosis method for harmonic drive systems based on multi-sensor data fusion and the gravitational search algorithm (GSA). As a critical component in robotic arms, harmonic drives are prone to failures due to wear, less grease, or improper loading, which can compromise system stability and production efficiency. To enhance diagnostic accuracy, the research employs wavelet packet decomposition (WPD) and empirical mode decomposition (EMD) to extract multi-scale features from vibration signals. These features are subsequently fused, and GSA is used to optimize the high-dimensional fused features, eliminating redundant data and mitigating overfitting. The optimized features are then input into a support vector machine (SVM) for fault classification, with K-fold cross-validation used to assess the model&amp;rsquo;s generalization capabilities. Experimental results demonstrate that the proposed diagnosis method, which integrates multi-sensor data fusion with GSA optimization, significantly improves fault diagnosis accuracy compared to methods using single-sensor signals or unoptimized features. This improvement is particularly notable in multi-class fault scenarios. Additionally, GSA&amp;rsquo;s global search capability effectively addresses overfitting issues caused by high-dimensional data, resulting in a diagnostic model with greater reliability and accuracy across various fault conditions. ]]></content:encoded> <dc:title>Fault Detection in Harmonic Drive Using Multi-Sensor Data Fusion and Gravitational Search Algorithm</dc:title> <dc:creator>Nan-Kai Hsieh</dc:creator> <dc:creator>Tsung-Yu Yu</dc:creator> <dc:identifier>doi: 10.3390/machines12120831</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-21</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-21</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Article</prism:section> <prism:startingPage>831</prism:startingPage> <prism:doi>10.3390/machines12120831</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/831</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/829"> <title>Machines, Vol. 12, Pages 829: A Survey of Planar Underactuated Mechanical System</title> <link>https://www.mdpi.com/2075-1702/12/12/829</link> <description>Planar underactuated mechanical systems have been a popular research issue in the area of mechanical systems and nonlinear control. This paper reviews the current research status of control methods for a class of planar underactuated manipulator (PUM) systems containing a single passive joint. Firstly, the general dynamics model and kinematics model of the PUM are given, and its control characteristics are introduced; secondly, according to the distribution position characteristics of the passive joints, the PUM is classified into the passive first joint system, the passive last joint system, and the passive intermediate joint system, and the analysis and discussion are carried out in respect to the existing intelligent control methods. Finally, in response to the above discussion, we provide a brief theoretical analysis and summarize the challenges faced by PUM, i.e., uncertainty and robustness of the system, unified control methods and research on underactuated systems with uncontrollable multi-passive joints; at the same time, the practical applications have certain limitations that need to be implemented subsequently, i.e., anti-jamming, multi-planar underactuated robotic arm co-control and spatial underactuated robotic arm system development. Aiming at the above challenges and problems in the control of PUM systems, we elaborate on them in points, and put forward the research directions and related ideas for future work, taking into account the contributions of the current work.</description> <pubDate>2024-11-21</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 829: A Survey of Planar Underactuated Mechanical System Machines <a href="https://www.mdpi.com/2075-1702/12/12/829">doi: 10.3390/machines12120829</a> Authors: Zixin Huang Chengsong Yu Ba Zeng Xiangyu Gong Hongjian Zhou Planar underactuated mechanical systems have been a popular research issue in the area of mechanical systems and nonlinear control. This paper reviews the current research status of control methods for a class of planar underactuated manipulator (PUM) systems containing a single passive joint. Firstly, the general dynamics model and kinematics model of the PUM are given, and its control characteristics are introduced; secondly, according to the distribution position characteristics of the passive joints, the PUM is classified into the passive first joint system, the passive last joint system, and the passive intermediate joint system, and the analysis and discussion are carried out in respect to the existing intelligent control methods. Finally, in response to the above discussion, we provide a brief theoretical analysis and summarize the challenges faced by PUM, i.e., uncertainty and robustness of the system, unified control methods and research on underactuated systems with uncontrollable multi-passive joints; at the same time, the practical applications have certain limitations that need to be implemented subsequently, i.e., anti-jamming, multi-planar underactuated robotic arm co-control and spatial underactuated robotic arm system development. Aiming at the above challenges and problems in the control of PUM systems, we elaborate on them in points, and put forward the research directions and related ideas for future work, taking into account the contributions of the current work. ]]></content:encoded> <dc:title>A Survey of Planar Underactuated Mechanical System</dc:title> <dc:creator>Zixin Huang</dc:creator> <dc:creator>Chengsong Yu</dc:creator> <dc:creator>Ba Zeng</dc:creator> <dc:creator>Xiangyu Gong</dc:creator> <dc:creator>Hongjian Zhou</dc:creator> <dc:identifier>doi: 10.3390/machines12120829</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-21</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-21</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Review</prism:section> <prism:startingPage>829</prism:startingPage> <prism:doi>10.3390/machines12120829</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/829</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/12/828"> <title>Machines, Vol. 12, Pages 828: Dynamics and Chaos Intensity Analysis of Under-Actuated Mechanism by Uniformity and Particle Swarm Optimization</title> <link>https://www.mdpi.com/2075-1702/12/12/828</link> <description>Generally, nonlinear systems have dynamic uncertainties, and under certain conditions, the systems exhibit different chaos intensities. Therefore, it is an important consideration for designers to realize the suppression and enhancement of chaos intensity under nonlinear factors according to the actual situation, but there are few research results on this problem. To investigate the dynamic performance and chaotic intensity of a nonlinear mechanism, a planar closed-chain under-actuated mechanism, which has not been extensively studied before, is taken as an example. It is worth noting that a small change in the parameters of a nonlinear system will cause a large change in the motion state of the system and even the mutual transformation between chaotic phenomena and periodic phenomena. To solve this problem, uniformity is used to evaluate the chaos intensity of the system. Finally, based on uniformity, the particle swarm optimization algorithm successfully achieves the suppression and enhancement of the chaos intensity of the closed-chain under-actuated five-bar mechanism by optimizing its linkage length and driving speed, and the results are verified by the experimental platform.</description> <pubDate>2024-11-21</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 828: Dynamics and Chaos Intensity Analysis of Under-Actuated Mechanism by Uniformity and Particle Swarm Optimization Machines <a href="https://www.mdpi.com/2075-1702/12/12/828">doi: 10.3390/machines12120828</a> Authors: Hui Li Yang Shu Yongping Gu Wuye Xiang Feng Zhang Generally, nonlinear systems have dynamic uncertainties, and under certain conditions, the systems exhibit different chaos intensities. Therefore, it is an important consideration for designers to realize the suppression and enhancement of chaos intensity under nonlinear factors according to the actual situation, but there are few research results on this problem. To investigate the dynamic performance and chaotic intensity of a nonlinear mechanism, a planar closed-chain under-actuated mechanism, which has not been extensively studied before, is taken as an example. It is worth noting that a small change in the parameters of a nonlinear system will cause a large change in the motion state of the system and even the mutual transformation between chaotic phenomena and periodic phenomena. To solve this problem, uniformity is used to evaluate the chaos intensity of the system. Finally, based on uniformity, the particle swarm optimization algorithm successfully achieves the suppression and enhancement of the chaos intensity of the closed-chain under-actuated five-bar mechanism by optimizing its linkage length and driving speed, and the results are verified by the experimental platform. ]]></content:encoded> <dc:title>Dynamics and Chaos Intensity Analysis of Under-Actuated Mechanism by Uniformity and Particle Swarm Optimization</dc:title> <dc:creator>Hui Li</dc:creator> <dc:creator>Yang Shu</dc:creator> <dc:creator>Yongping Gu</dc:creator> <dc:creator>Wuye Xiang</dc:creator> <dc:creator>Feng Zhang</dc:creator> <dc:identifier>doi: 10.3390/machines12120828</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-21</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-21</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>12</prism:number> <prism:section>Article</prism:section> <prism:startingPage>828</prism:startingPage> <prism:doi>10.3390/machines12120828</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/12/828</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/827"> <title>Machines, Vol. 12, Pages 827: An Advanced Approach for Predicting Workpiece Surface Roughness Using Finite Element Method and Image Processing Techniques</title> <link>https://www.mdpi.com/2075-1702/12/11/827</link> <description>Workpiece surface quality is a critical metric for assessing machining quality. However, due to the complex coupling characteristics of cutting factors, accurately predicting surface roughness remains challenging. Typically, roughness is measured post-machining using specialized instruments, which delays feedback and hampers timely problem detection, ultimately resulting in cutting resource wastage. To address this issue, this paper introduces a predictive model for workpiece surface roughness based on the finite element (FE) method and advanced image processing techniques. Initially, an orthogonal turning experiment was designed, and an FE cutting model was constructed to assess the distribution of cutting forces and temperatures under varying cutting parameters. Image processing methods (including mesh calibration, edge extraction, and contour fitting) were then applied to extract surface characteristics from the FE simulation outputs, yielding preliminary estimates of surface roughness. By employing range and regression analyses methods, this study quantitatively evaluates the interdependencies among cutting parameters, forces, temperatures, and roughness, subsequently formulating a multivariate regression model to predict surface roughness. Finally, a turning experiment under actual working conditions was conducted, confirming the model&amp;rsquo;s capacity to predict the Ra trend with an accuracy of 85.07%. Thus, the proposed model provides a precise predictive tool for surface roughness, offering valuable guidance for optimizing machining parameters and supporting proactive control in the turning process, ultimately enhancing machining efficiency and quality.</description> <pubDate>2024-11-20</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 827: An Advanced Approach for Predicting Workpiece Surface Roughness Using Finite Element Method and Image Processing Techniques Machines <a href="https://www.mdpi.com/2075-1702/12/11/827">doi: 10.3390/machines12110827</a> Authors: Taoming Chen Chun Li Zhexiang Zou Qi Han Bing Li Fengshou Gu Andrew D. Ball Workpiece surface quality is a critical metric for assessing machining quality. However, due to the complex coupling characteristics of cutting factors, accurately predicting surface roughness remains challenging. Typically, roughness is measured post-machining using specialized instruments, which delays feedback and hampers timely problem detection, ultimately resulting in cutting resource wastage. To address this issue, this paper introduces a predictive model for workpiece surface roughness based on the finite element (FE) method and advanced image processing techniques. Initially, an orthogonal turning experiment was designed, and an FE cutting model was constructed to assess the distribution of cutting forces and temperatures under varying cutting parameters. Image processing methods (including mesh calibration, edge extraction, and contour fitting) were then applied to extract surface characteristics from the FE simulation outputs, yielding preliminary estimates of surface roughness. By employing range and regression analyses methods, this study quantitatively evaluates the interdependencies among cutting parameters, forces, temperatures, and roughness, subsequently formulating a multivariate regression model to predict surface roughness. Finally, a turning experiment under actual working conditions was conducted, confirming the model&amp;rsquo;s capacity to predict the Ra trend with an accuracy of 85.07%. Thus, the proposed model provides a precise predictive tool for surface roughness, offering valuable guidance for optimizing machining parameters and supporting proactive control in the turning process, ultimately enhancing machining efficiency and quality. ]]></content:encoded> <dc:title>An Advanced Approach for Predicting Workpiece Surface Roughness Using Finite Element Method and Image Processing Techniques</dc:title> <dc:creator>Taoming Chen</dc:creator> <dc:creator>Chun Li</dc:creator> <dc:creator>Zhexiang Zou</dc:creator> <dc:creator>Qi Han</dc:creator> <dc:creator>Bing Li</dc:creator> <dc:creator>Fengshou Gu</dc:creator> <dc:creator>Andrew D. Ball</dc:creator> <dc:identifier>doi: 10.3390/machines12110827</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-20</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-20</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>827</prism:startingPage> <prism:doi>10.3390/machines12110827</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/827</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/826"> <title>Machines, Vol. 12, Pages 826: Efficiency Analysis and Optimization of Two-Speed-Region Operation of Permanent Magnet Synchronous Motor Taking into Account Iron Loss Based on Linear Non-Equilibrium Thermodynamics</title> <link>https://www.mdpi.com/2075-1702/12/11/826</link> <description>In this article, the linear non-equilibrium thermodynamic approach is used to mathematically describe the energy regularities of an interior permanent magnet synchronous motor (IPMSM), taking into account iron loss. The IPMSM is considered a linear power converter (PC) that is multiple-linearized at operating points with a given angular velocity and load torque. A universal description of such a PC by a system of dimensionless parameters and characteristics made it possible to analyze the perfection of energy conversion in the object. For IPMSM, taking into account iron loss, a mathematical model of the corresponding PC has been built, and an algorithm and research program have been developed, which is valid in a wide range of machine speed regulations. This allows you to choose the optimal points of PC operation according to the maximum efficiency criteria and obtain the efficiency maps for IPMSM in different speed regions. The results of the studies demonstrate the effectiveness of the proposed method for determining the references of the d and q components of the armature current for both the loss-minimization strategy at the constant torque range of motor speed and the flux-weakening strategy in the constant power range.</description> <pubDate>2024-11-20</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 826: Efficiency Analysis and Optimization of Two-Speed-Region Operation of Permanent Magnet Synchronous Motor Taking into Account Iron Loss Based on Linear Non-Equilibrium Thermodynamics Machines <a href="https://www.mdpi.com/2075-1702/12/11/826">doi: 10.3390/machines12110826</a> Authors: Ihor Shchur Yurii Biletskyi Bohdan Kopchak In this article, the linear non-equilibrium thermodynamic approach is used to mathematically describe the energy regularities of an interior permanent magnet synchronous motor (IPMSM), taking into account iron loss. The IPMSM is considered a linear power converter (PC) that is multiple-linearized at operating points with a given angular velocity and load torque. A universal description of such a PC by a system of dimensionless parameters and characteristics made it possible to analyze the perfection of energy conversion in the object. For IPMSM, taking into account iron loss, a mathematical model of the corresponding PC has been built, and an algorithm and research program have been developed, which is valid in a wide range of machine speed regulations. This allows you to choose the optimal points of PC operation according to the maximum efficiency criteria and obtain the efficiency maps for IPMSM in different speed regions. The results of the studies demonstrate the effectiveness of the proposed method for determining the references of the d and q components of the armature current for both the loss-minimization strategy at the constant torque range of motor speed and the flux-weakening strategy in the constant power range. ]]></content:encoded> <dc:title>Efficiency Analysis and Optimization of Two-Speed-Region Operation of Permanent Magnet Synchronous Motor Taking into Account Iron Loss Based on Linear Non-Equilibrium Thermodynamics</dc:title> <dc:creator>Ihor Shchur</dc:creator> <dc:creator>Yurii Biletskyi</dc:creator> <dc:creator>Bohdan Kopchak</dc:creator> <dc:identifier>doi: 10.3390/machines12110826</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-20</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-20</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>826</prism:startingPage> <prism:doi>10.3390/machines12110826</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/826</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/825"> <title>Machines, Vol. 12, Pages 825: Geometric Constraint Programming (GCP) Implemented Through GeoGebra to Study/Design Planar Linkages</title> <link>https://www.mdpi.com/2075-1702/12/11/825</link> <description>In the study and design of planar mechanisms, graphical techniques for solving kinematic analysis/synthesis and kinetostatics problems have regained interest due to the availability of advanced drawing tools (e.g., CAD software). These techniques offer a deeper physical understanding of a mechanism&amp;rsquo;s behavior, which can enhance a designer&amp;rsquo;s intuition and help students develop their skills. Geometric Constraint Programming (GCP) is the term used to describe this modern approach to implementing these techniques. GeoGebra is an open-source platform designed for the interactive learning and teaching of mathematics and related STEM disciplines. It offers an object-oriented programming language and a wide range of geometric tools that can be leveraged to implement GCP. This work presents a systematic technique for studying and designing planar linkages, based on Assur&amp;rsquo;s groups and GeoGebra&amp;rsquo;s tools. Although some kinematic analyses and syntheses of planar linkages using GeoGebra have been previously introduced, the proposed systematic approach is novel and could serve as a guide for implementing similar problem-solving methods in other graphical environments. Several case studies will be presented to illustrate this novel approach in detail.</description> <pubDate>2024-11-18</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 825: Geometric Constraint Programming (GCP) Implemented Through GeoGebra to Study/Design Planar Linkages Machines <a href="https://www.mdpi.com/2075-1702/12/11/825">doi: 10.3390/machines12110825</a> Authors: Raffaele Di Gregorio Tommaso Cinti In the study and design of planar mechanisms, graphical techniques for solving kinematic analysis/synthesis and kinetostatics problems have regained interest due to the availability of advanced drawing tools (e.g., CAD software). These techniques offer a deeper physical understanding of a mechanism&amp;rsquo;s behavior, which can enhance a designer&amp;rsquo;s intuition and help students develop their skills. Geometric Constraint Programming (GCP) is the term used to describe this modern approach to implementing these techniques. GeoGebra is an open-source platform designed for the interactive learning and teaching of mathematics and related STEM disciplines. It offers an object-oriented programming language and a wide range of geometric tools that can be leveraged to implement GCP. This work presents a systematic technique for studying and designing planar linkages, based on Assur&amp;rsquo;s groups and GeoGebra&amp;rsquo;s tools. Although some kinematic analyses and syntheses of planar linkages using GeoGebra have been previously introduced, the proposed systematic approach is novel and could serve as a guide for implementing similar problem-solving methods in other graphical environments. Several case studies will be presented to illustrate this novel approach in detail. ]]></content:encoded> <dc:title>Geometric Constraint Programming (GCP) Implemented Through GeoGebra to Study/Design Planar Linkages</dc:title> <dc:creator>Raffaele Di Gregorio</dc:creator> <dc:creator>Tommaso Cinti</dc:creator> <dc:identifier>doi: 10.3390/machines12110825</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-18</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-18</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>825</prism:startingPage> <prism:doi>10.3390/machines12110825</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/825</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/824"> <title>Machines, Vol. 12, Pages 824: A New Paradigm in Torque Transfer: Rethinking Shaft Key Placement</title> <link>https://www.mdpi.com/2075-1702/12/11/824</link> <description>In this study, an innovative approach to torque transmission mechanisms within the context of hub&amp;ndash;shaft connections is introduced by exploring the viability of a transverse key configuration. Unlike traditional longitudinal key placements, the proposed method positions the key perpendicularly to the rotational axis, resembling a pin joint at the interface of the shaft and the hub. This research primarily aims to elucidate the maximum torque capacity of such a connection, juxtaposed against conventional methodologies. Employing a rigorous analytical framework, equations originally designed for pin connections are adapted to suit the unique geometric and loading conditions presented by the transverse key. This adaptation is essential in quantifying the resultant torque that the connection could sustain without failure. The study meticulously accounts for the variations in key dimensions and the inherent limitations posed by the method&amp;rsquo;s reliance on the end-face connection strategy. Comparative analyses underscore the manufacturing advantages of the proposed method, notably its reduced machinery requirements, by leveraging standard milling processes over more complex machining operations that are traditionally associated with keyway or keyseat creation. However, the findings also highlight the compromised torque transmission capability due to the reduced contact area, a significant consideration for designers. This research contributes to the broader discourse on mechanical connection innovations, offering a novel perspective on torque transmission solutions. It provides a foundation for future exploration into alternative key configurations, potentially revolutionizing hub&amp;ndash;shaft connection designs in applications constrained by manufacturing capabilities or cost considerations.</description> <pubDate>2024-11-18</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 824: A New Paradigm in Torque Transfer: Rethinking Shaft Key Placement Machines <a href="https://www.mdpi.com/2075-1702/12/11/824">doi: 10.3390/machines12110824</a> Authors: Matus Veres Frantisek Brumercik Ronald Bastovansky Robert Kohar In this study, an innovative approach to torque transmission mechanisms within the context of hub&amp;ndash;shaft connections is introduced by exploring the viability of a transverse key configuration. Unlike traditional longitudinal key placements, the proposed method positions the key perpendicularly to the rotational axis, resembling a pin joint at the interface of the shaft and the hub. This research primarily aims to elucidate the maximum torque capacity of such a connection, juxtaposed against conventional methodologies. Employing a rigorous analytical framework, equations originally designed for pin connections are adapted to suit the unique geometric and loading conditions presented by the transverse key. This adaptation is essential in quantifying the resultant torque that the connection could sustain without failure. The study meticulously accounts for the variations in key dimensions and the inherent limitations posed by the method&amp;rsquo;s reliance on the end-face connection strategy. Comparative analyses underscore the manufacturing advantages of the proposed method, notably its reduced machinery requirements, by leveraging standard milling processes over more complex machining operations that are traditionally associated with keyway or keyseat creation. However, the findings also highlight the compromised torque transmission capability due to the reduced contact area, a significant consideration for designers. This research contributes to the broader discourse on mechanical connection innovations, offering a novel perspective on torque transmission solutions. It provides a foundation for future exploration into alternative key configurations, potentially revolutionizing hub&amp;ndash;shaft connection designs in applications constrained by manufacturing capabilities or cost considerations. ]]></content:encoded> <dc:title>A New Paradigm in Torque Transfer: Rethinking Shaft Key Placement</dc:title> <dc:creator>Matus Veres</dc:creator> <dc:creator>Frantisek Brumercik</dc:creator> <dc:creator>Ronald Bastovansky</dc:creator> <dc:creator>Robert Kohar</dc:creator> <dc:identifier>doi: 10.3390/machines12110824</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-18</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-18</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>824</prism:startingPage> <prism:doi>10.3390/machines12110824</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/824</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/823"> <title>Machines, Vol. 12, Pages 823: A Numerical Method to Determine the Radial Electromagnetic Force of the Switched Reluctance Motor Under Air Gap Eccentricity</title> <link>https://www.mdpi.com/2075-1702/12/11/823</link> <description>This paper discusses a numerical model for determining the radial electromagnetic force of switched reluctance motors under air gap eccentricity (vertical and tilt eccentricities). The authors compare experimental and simulation results to demonstrate that the proposed model can accurately simulate the behavior of radial forces in switched reluctance motors under various types of air gap eccentricity. Moreover, the paper attempts to establish a dynamic model of the SRM and nalyze the performance of the radial electromagnetic force under air gap eccentricity in typical scenarios.</description> <pubDate>2024-11-18</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 823: A Numerical Method to Determine the Radial Electromagnetic Force of the Switched Reluctance Motor Under Air Gap Eccentricity Machines <a href="https://www.mdpi.com/2075-1702/12/11/823">doi: 10.3390/machines12110823</a> Authors: Tianji Ma Zhaoxue Deng Wanli Liu Mengmeng Hou This paper discusses a numerical model for determining the radial electromagnetic force of switched reluctance motors under air gap eccentricity (vertical and tilt eccentricities). The authors compare experimental and simulation results to demonstrate that the proposed model can accurately simulate the behavior of radial forces in switched reluctance motors under various types of air gap eccentricity. Moreover, the paper attempts to establish a dynamic model of the SRM and nalyze the performance of the radial electromagnetic force under air gap eccentricity in typical scenarios. ]]></content:encoded> <dc:title>A Numerical Method to Determine the Radial Electromagnetic Force of the Switched Reluctance Motor Under Air Gap Eccentricity</dc:title> <dc:creator>Tianji Ma</dc:creator> <dc:creator>Zhaoxue Deng</dc:creator> <dc:creator>Wanli Liu</dc:creator> <dc:creator>Mengmeng Hou</dc:creator> <dc:identifier>doi: 10.3390/machines12110823</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-18</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-18</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>823</prism:startingPage> <prism:doi>10.3390/machines12110823</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/823</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/822"> <title>Machines, Vol. 12, Pages 822: Acoustoelastic Theory and Mode Analysis of Bolted Structures Under Preload</title> <link>https://www.mdpi.com/2075-1702/12/11/822</link> <description>Bolted connections are a common feature of connection in mechanical structures, employed to secure connected parts by tightening nuts and providing preload. The preload is susceptible to various factors leading to potential bolt loosening. The acoustoelastic theory is the most common measure of a bolt structure&amp;rsquo;s stress. The present study investigates the relationship between the inherent properties of a structure and its acousticelastic properties. The modal response of the bolted structure under different preload forces is studied by translating the acoustoelastic relationship of the structure into an analysis of its intrinsic properties. The modal analysis reflects the relative change in wave velocity to be determined implicitly based on the eigenfrequencies of the structure. A frequency formulation of classical bolted structures based on acoustoelastic theory is presented in this paper to conduct the intrinsic characteristic analysis of bolted structures. The COMSOL5.4 simulation results are under the acoustic elasticity coefficients for ultrasonic wave propagation in bolt structures, as predicted by the acoustic elasticity theory, and the present solutions are compared with those available in the literature to confirm their validity. A systematic parameter study for bolted structures under the varying preloads with different material parameters, Lame elastic constants, Murnaghan third-order elastic constants, and structural parameters are presented. These results may serve as a benchmark for researchers in this field.</description> <pubDate>2024-11-18</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 822: Acoustoelastic Theory and Mode Analysis of Bolted Structures Under Preload Machines <a href="https://www.mdpi.com/2075-1702/12/11/822">doi: 10.3390/machines12110822</a> Authors: Lei Zhao Rui Kuang Guizhong Tian Xiaona Shi Li Sun Bolted connections are a common feature of connection in mechanical structures, employed to secure connected parts by tightening nuts and providing preload. The preload is susceptible to various factors leading to potential bolt loosening. The acoustoelastic theory is the most common measure of a bolt structure&amp;rsquo;s stress. The present study investigates the relationship between the inherent properties of a structure and its acousticelastic properties. The modal response of the bolted structure under different preload forces is studied by translating the acoustoelastic relationship of the structure into an analysis of its intrinsic properties. The modal analysis reflects the relative change in wave velocity to be determined implicitly based on the eigenfrequencies of the structure. A frequency formulation of classical bolted structures based on acoustoelastic theory is presented in this paper to conduct the intrinsic characteristic analysis of bolted structures. The COMSOL5.4 simulation results are under the acoustic elasticity coefficients for ultrasonic wave propagation in bolt structures, as predicted by the acoustic elasticity theory, and the present solutions are compared with those available in the literature to confirm their validity. A systematic parameter study for bolted structures under the varying preloads with different material parameters, Lame elastic constants, Murnaghan third-order elastic constants, and structural parameters are presented. These results may serve as a benchmark for researchers in this field. ]]></content:encoded> <dc:title>Acoustoelastic Theory and Mode Analysis of Bolted Structures Under Preload</dc:title> <dc:creator>Lei Zhao</dc:creator> <dc:creator>Rui Kuang</dc:creator> <dc:creator>Guizhong Tian</dc:creator> <dc:creator>Xiaona Shi</dc:creator> <dc:creator>Li Sun</dc:creator> <dc:identifier>doi: 10.3390/machines12110822</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-18</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-18</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>822</prism:startingPage> <prism:doi>10.3390/machines12110822</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/822</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/821"> <title>Machines, Vol. 12, Pages 821: Research on Optimal Design of Ultra-High-Speed Motors Based on Multi-Physical Field Coupling Under Mechanical Boundary Constraints</title> <link>https://www.mdpi.com/2075-1702/12/11/821</link> <description>This study investigates the impact of rotor structure, material selection, and cooling methods on ultra-high-speed motor performance, revealing performance variation laws under multi-physical field coupling. Considering mechanical boundary constraints, we propose an optimization design method based on a multi-physical field coupling model. Using a MaxPro experimental design, initial samples are obtained and fitted using a Kriging surrogate model. The NSGA-2 algorithm is then applied for optimization, with Relative Maximum Absolute Error (RMAE) and Relative Average Absolute Error (RAAE) employed for accuracy evaluation. The Kriging model is iteratively updated based on evaluation results until the optimal design is achieved. This method enhances motor performance, ensures mechanical boundary conditions, and reduces computational load. Experimental results show significant improvements in efficiency and power density. This study provides theoretical support and technical guidance for ultra-high-speed motor design and offers new ideas for related motor research and development. Future work will explore more efficient and intelligent optimization algorithms to continuously advance ultra-high-speed motor technology.</description> <pubDate>2024-11-18</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 821: Research on Optimal Design of Ultra-High-Speed Motors Based on Multi-Physical Field Coupling Under Mechanical Boundary Constraints Machines <a href="https://www.mdpi.com/2075-1702/12/11/821">doi: 10.3390/machines12110821</a> Authors: Jianguo Bu Xudong Lan Weifeng Zhang Yan Yu Hailong Pang Wei Lei This study investigates the impact of rotor structure, material selection, and cooling methods on ultra-high-speed motor performance, revealing performance variation laws under multi-physical field coupling. Considering mechanical boundary constraints, we propose an optimization design method based on a multi-physical field coupling model. Using a MaxPro experimental design, initial samples are obtained and fitted using a Kriging surrogate model. The NSGA-2 algorithm is then applied for optimization, with Relative Maximum Absolute Error (RMAE) and Relative Average Absolute Error (RAAE) employed for accuracy evaluation. The Kriging model is iteratively updated based on evaluation results until the optimal design is achieved. This method enhances motor performance, ensures mechanical boundary conditions, and reduces computational load. Experimental results show significant improvements in efficiency and power density. This study provides theoretical support and technical guidance for ultra-high-speed motor design and offers new ideas for related motor research and development. Future work will explore more efficient and intelligent optimization algorithms to continuously advance ultra-high-speed motor technology. ]]></content:encoded> <dc:title>Research on Optimal Design of Ultra-High-Speed Motors Based on Multi-Physical Field Coupling Under Mechanical Boundary Constraints</dc:title> <dc:creator>Jianguo Bu</dc:creator> <dc:creator>Xudong Lan</dc:creator> <dc:creator>Weifeng Zhang</dc:creator> <dc:creator>Yan Yu</dc:creator> <dc:creator>Hailong Pang</dc:creator> <dc:creator>Wei Lei</dc:creator> <dc:identifier>doi: 10.3390/machines12110821</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-18</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-18</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>821</prism:startingPage> <prism:doi>10.3390/machines12110821</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/821</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/820"> <title>Machines, Vol. 12, Pages 820: Assessing the Critical Factors Leading to the Failure of the Industrial Pressure Relief Valve Through a Hybrid MCDM-FMEA Approach</title> <link>https://www.mdpi.com/2075-1702/12/11/820</link> <description>Industrial pressure relief valves must function reliably and effectively to protect pressurized systems from excessive pressure conditions. These valves are essential safety devices that act as cushions to protect piping systems, equipment, and vessels from the risks of high pressure, which can cause damage or even explosions. The objectives of this study were to minimize valve failures, decrease the number of rejected valves in the production line, and enhance the overall quality of pressure relief valves. This work introduces an integrated quality improvement methodology known as the hybrid multi-criteria decision-making (MCDM)&amp;mdash;failure mode and effects analysis (FMEA) approach. This approach is based on prioritizing crucial factors for any failure modes in the industrial setting. The presented case study demonstrates the application of a hybrid approach for identifying the fundamental causes of industrial pressure relief valve failure modes and malfunctions. This investigation highlights the applicability of FMEA as a methodology for determining causes and executing remedial actions to keep failures from happening again. FMEA helps uncover the underlying causes of industrial pressure relief valve failures, while the integration of the hybrid MCDM methodology enables the application of four integrated MCDM methods to identify crucial factors. The adopted model addresses the shortcomings of the conventional FMEA by accurately analyzing the relationships between the risk factors and by utilizing several MCDM methods to rank failure modes. Following the application of the adopted methodology, it was discovered that the high-risk failure modes for the pressure relief valve included misalignment of wire, normal wear/aging, rejection of machined parts, mismatch of mating parts, and corrosion. Therefore, risk managers should prioritize developing improvement strategies for these five failure modes. Similarly, failures comprising debris, delayed valve opening, internal leakage, premature valve opening, and burr foreign particles were determined as second essential groups for improvement.</description> <pubDate>2024-11-17</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 820: Assessing the Critical Factors Leading to the Failure of the Industrial Pressure Relief Valve Through a Hybrid MCDM-FMEA Approach Machines <a href="https://www.mdpi.com/2075-1702/12/11/820">doi: 10.3390/machines12110820</a> Authors: Pradnya Kuchekar Ajay S. Bhongade Ateekh Ur Rehman Syed Hammad Mian Industrial pressure relief valves must function reliably and effectively to protect pressurized systems from excessive pressure conditions. These valves are essential safety devices that act as cushions to protect piping systems, equipment, and vessels from the risks of high pressure, which can cause damage or even explosions. The objectives of this study were to minimize valve failures, decrease the number of rejected valves in the production line, and enhance the overall quality of pressure relief valves. This work introduces an integrated quality improvement methodology known as the hybrid multi-criteria decision-making (MCDM)&amp;mdash;failure mode and effects analysis (FMEA) approach. This approach is based on prioritizing crucial factors for any failure modes in the industrial setting. The presented case study demonstrates the application of a hybrid approach for identifying the fundamental causes of industrial pressure relief valve failure modes and malfunctions. This investigation highlights the applicability of FMEA as a methodology for determining causes and executing remedial actions to keep failures from happening again. FMEA helps uncover the underlying causes of industrial pressure relief valve failures, while the integration of the hybrid MCDM methodology enables the application of four integrated MCDM methods to identify crucial factors. The adopted model addresses the shortcomings of the conventional FMEA by accurately analyzing the relationships between the risk factors and by utilizing several MCDM methods to rank failure modes. Following the application of the adopted methodology, it was discovered that the high-risk failure modes for the pressure relief valve included misalignment of wire, normal wear/aging, rejection of machined parts, mismatch of mating parts, and corrosion. Therefore, risk managers should prioritize developing improvement strategies for these five failure modes. Similarly, failures comprising debris, delayed valve opening, internal leakage, premature valve opening, and burr foreign particles were determined as second essential groups for improvement. ]]></content:encoded> <dc:title>Assessing the Critical Factors Leading to the Failure of the Industrial Pressure Relief Valve Through a Hybrid MCDM-FMEA Approach</dc:title> <dc:creator>Pradnya Kuchekar</dc:creator> <dc:creator>Ajay S. Bhongade</dc:creator> <dc:creator>Ateekh Ur Rehman</dc:creator> <dc:creator>Syed Hammad Mian</dc:creator> <dc:identifier>doi: 10.3390/machines12110820</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-17</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-17</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>820</prism:startingPage> <prism:doi>10.3390/machines12110820</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/820</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/819"> <title>Machines, Vol. 12, Pages 819: Design of a Gravity Ropeway in Nepal: A Methodological Analysis for Appropriate Technologies</title> <link>https://www.mdpi.com/2075-1702/12/11/819</link> <description>This article describes the complete development of a design project for a context-integrated appropriate technology, a gravity ropeway for transporting agricultural products in remote areas of Nepal. The main purpose was to improve and optimize existing gravity ropeway designs, prioritizing simplicity, safety, and local manufacturability and maintenance. The design process followed a phased methodological approach used in machine design, which included stages of definition, conceptual design, materialization, and detailed design. The results of the ropeway installation demonstrate a reduction in the time and effort required by farmers to transport their products, consequently leading to a significant improvement in their quality of life. Despite the methodology followed, deficiencies were identified in the project execution procedure: lack of documentation and lack of explicit consideration of the local context in the design specifications, which could compromise the continuity and success of the project. This analysis highlights the need to adapt traditional design methodologies to appropriate technology projects. Specific procedures that address the characteristics of the local environment should be included to integrate the design into the context and accurately determine the needs of users in development projects.</description> <pubDate>2024-11-17</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 819: Design of a Gravity Ropeway in Nepal: A Methodological Analysis for Appropriate Technologies Machines <a href="https://www.mdpi.com/2075-1702/12/11/819">doi: 10.3390/machines12110819</a> Authors: Elena Blanco-Romero Carles Dom猫nech-Mestres Manuel Ayala-Chauvin This article describes the complete development of a design project for a context-integrated appropriate technology, a gravity ropeway for transporting agricultural products in remote areas of Nepal. The main purpose was to improve and optimize existing gravity ropeway designs, prioritizing simplicity, safety, and local manufacturability and maintenance. The design process followed a phased methodological approach used in machine design, which included stages of definition, conceptual design, materialization, and detailed design. The results of the ropeway installation demonstrate a reduction in the time and effort required by farmers to transport their products, consequently leading to a significant improvement in their quality of life. Despite the methodology followed, deficiencies were identified in the project execution procedure: lack of documentation and lack of explicit consideration of the local context in the design specifications, which could compromise the continuity and success of the project. This analysis highlights the need to adapt traditional design methodologies to appropriate technology projects. Specific procedures that address the characteristics of the local environment should be included to integrate the design into the context and accurately determine the needs of users in development projects. ]]></content:encoded> <dc:title>Design of a Gravity Ropeway in Nepal: A Methodological Analysis for Appropriate Technologies</dc:title> <dc:creator>Elena Blanco-Romero</dc:creator> <dc:creator>Carles Dom猫nech-Mestres</dc:creator> <dc:creator>Manuel Ayala-Chauvin</dc:creator> <dc:identifier>doi: 10.3390/machines12110819</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-17</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-17</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>819</prism:startingPage> <prism:doi>10.3390/machines12110819</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/819</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/818"> <title>Machines, Vol. 12, Pages 818: Automatic Jig-Assisted Battery Exchange for Lightweight Drones</title> <link>https://www.mdpi.com/2075-1702/12/11/818</link> <description>Drones utilize rechargeable batteries as a power source. Operating a drone requires human interaction with the exchange or recharge process of these batteries. This can provide limits for drones, which is why some use cases for drones could benefit from automated battery exchange. The purpose of this work was to research how a robotic arm could be used to automatically exchange flight batteries in flying drones without interference from operators and create a proof-of-concept system for evaluation. The devised method was based around a separate jig, which would hold the drone in place during the exchange operation, where battery exchange itself was handled by the use of a robotic arm. The constructed prototype could exchange flight batteries in drones in under two minutes with reasonable perpetuity and reliability.</description> <pubDate>2024-11-16</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 818: Automatic Jig-Assisted Battery Exchange for Lightweight Drones Machines <a href="https://www.mdpi.com/2075-1702/12/11/818">doi: 10.3390/machines12110818</a> Authors: Aleksi Vilkki Antti Tikanm盲ki Juha R枚ning Drones utilize rechargeable batteries as a power source. Operating a drone requires human interaction with the exchange or recharge process of these batteries. This can provide limits for drones, which is why some use cases for drones could benefit from automated battery exchange. The purpose of this work was to research how a robotic arm could be used to automatically exchange flight batteries in flying drones without interference from operators and create a proof-of-concept system for evaluation. The devised method was based around a separate jig, which would hold the drone in place during the exchange operation, where battery exchange itself was handled by the use of a robotic arm. The constructed prototype could exchange flight batteries in drones in under two minutes with reasonable perpetuity and reliability. ]]></content:encoded> <dc:title>Automatic Jig-Assisted Battery Exchange for Lightweight Drones</dc:title> <dc:creator>Aleksi Vilkki</dc:creator> <dc:creator>Antti Tikanm盲ki</dc:creator> <dc:creator>Juha R枚ning</dc:creator> <dc:identifier>doi: 10.3390/machines12110818</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-16</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-16</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>818</prism:startingPage> <prism:doi>10.3390/machines12110818</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/818</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/817"> <title>Machines, Vol. 12, Pages 817: PDA Nanoparticle-Induced Lubricating Film Formation in Marine Environments: An Active Approach</title> <link>https://www.mdpi.com/2075-1702/12/11/817</link> <description>The low viscosity of water-lubricated films compromises their load-bearing capacity, posing challenges for practical application. Enhancing the lubrication stability of these films under load is critical for the successful use of seawater-lubricated bearings in engineering. Polydopamine (PDA) shows great potential to address this issue due to its strong bio-inspired adhesion and hydration lubrication properties. Thus, PDA nanoparticles and seawater suspensions were synthesized to promote adhesive lubricating film formation under dynamic friction. The lubrication properties of PDA suspensions were evaluated on Cu ball and ultra-high molecular weight polyethylene (UHMWPE) tribo-pairs, with a detailed comparison to seawater. The results show PDA nanoparticles provide excellent adhesion and lubrication, enhancing the formation of lubricating films during friction with seawater. Under identical conditions, PDA suspensions demonstrated the lowest friction coefficient and minimal wear. At 3 N, friction decreased by 56% and wear by 47% compared to distilled water. These findings suggest a novel strategy for using PDA as a lubricant in seawater for engineering applications.</description> <pubDate>2024-11-16</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 817: PDA Nanoparticle-Induced Lubricating Film Formation in Marine Environments: An Active Approach Machines <a href="https://www.mdpi.com/2075-1702/12/11/817">doi: 10.3390/machines12110817</a> Authors: Xinqi Zou Zhenghao Ge Chaobao Wang Yuyang Xi The low viscosity of water-lubricated films compromises their load-bearing capacity, posing challenges for practical application. Enhancing the lubrication stability of these films under load is critical for the successful use of seawater-lubricated bearings in engineering. Polydopamine (PDA) shows great potential to address this issue due to its strong bio-inspired adhesion and hydration lubrication properties. Thus, PDA nanoparticles and seawater suspensions were synthesized to promote adhesive lubricating film formation under dynamic friction. The lubrication properties of PDA suspensions were evaluated on Cu ball and ultra-high molecular weight polyethylene (UHMWPE) tribo-pairs, with a detailed comparison to seawater. The results show PDA nanoparticles provide excellent adhesion and lubrication, enhancing the formation of lubricating films during friction with seawater. Under identical conditions, PDA suspensions demonstrated the lowest friction coefficient and minimal wear. At 3 N, friction decreased by 56% and wear by 47% compared to distilled water. These findings suggest a novel strategy for using PDA as a lubricant in seawater for engineering applications. ]]></content:encoded> <dc:title>PDA Nanoparticle-Induced Lubricating Film Formation in Marine Environments: An Active Approach</dc:title> <dc:creator>Xinqi Zou</dc:creator> <dc:creator>Zhenghao Ge</dc:creator> <dc:creator>Chaobao Wang</dc:creator> <dc:creator>Yuyang Xi</dc:creator> <dc:identifier>doi: 10.3390/machines12110817</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-16</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-16</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>817</prism:startingPage> <prism:doi>10.3390/machines12110817</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/817</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/816"> <title>Machines, Vol. 12, Pages 816: Development of Deterministic Communication for In-Vehicle Networks Based on Software-Defined Time-Sensitive Networking</title> <link>https://www.mdpi.com/2075-1702/12/11/816</link> <description>To support more advanced functionality in vehicles, there is the challenge of deterministic and reliable transmission of sensor data and control signals. Time-sensitive networking (TSN) is the most promising candidate to meet this demand by leveraging IEEE 802.1 ethernet standards, which include time synchronization, traffic shaping, and low-latency forwarding mechanisms. To explore the implementation of TSN for in-vehicle networks (IVN), this paper proposes a robust integer linear programming (ILP)-based scheduling model for time-sensitive data streams to mitigate the vulnerabilities of the time-aware shaper (TAS) mechanism in practice. Furthermore, we integrate this scheduling model into a software-defined time-sensitive networking (SD-TSN) architecture to automate the scheduling computations and configurations in the design phase. This SD-TSN architecture can offer a flexible and programmable approach to network management, enabling precise control over timing constraints and quality-of-service (QoS) parameters for time-sensitive traffic. Firstly, data transmission requirements are gathered by the centralized user configuration (CUC) module to acquire traffic information. Subsequently, the CNC module transfers the computed results of routing and scheduling to the YANG model for configuration delivery. Finally, automotive TSN switches can complete local configuration by parsing the received configuration messages. Through an experimental validation based on a physical platform, this study demonstrates the effectiveness of the scheduling algorithm and SD-TSN architecture in enhancing deterministic communication for in-vehicle networks.</description> <pubDate>2024-11-15</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 816: Development of Deterministic Communication for In-Vehicle Networks Based on Software-Defined Time-Sensitive Networking Machines <a href="https://www.mdpi.com/2075-1702/12/11/816">doi: 10.3390/machines12110816</a> Authors: Binqi Li Yuan Zhu Qin Liu Xiangxi Yao To support more advanced functionality in vehicles, there is the challenge of deterministic and reliable transmission of sensor data and control signals. Time-sensitive networking (TSN) is the most promising candidate to meet this demand by leveraging IEEE 802.1 ethernet standards, which include time synchronization, traffic shaping, and low-latency forwarding mechanisms. To explore the implementation of TSN for in-vehicle networks (IVN), this paper proposes a robust integer linear programming (ILP)-based scheduling model for time-sensitive data streams to mitigate the vulnerabilities of the time-aware shaper (TAS) mechanism in practice. Furthermore, we integrate this scheduling model into a software-defined time-sensitive networking (SD-TSN) architecture to automate the scheduling computations and configurations in the design phase. This SD-TSN architecture can offer a flexible and programmable approach to network management, enabling precise control over timing constraints and quality-of-service (QoS) parameters for time-sensitive traffic. Firstly, data transmission requirements are gathered by the centralized user configuration (CUC) module to acquire traffic information. Subsequently, the CNC module transfers the computed results of routing and scheduling to the YANG model for configuration delivery. Finally, automotive TSN switches can complete local configuration by parsing the received configuration messages. Through an experimental validation based on a physical platform, this study demonstrates the effectiveness of the scheduling algorithm and SD-TSN architecture in enhancing deterministic communication for in-vehicle networks. ]]></content:encoded> <dc:title>Development of Deterministic Communication for In-Vehicle Networks Based on Software-Defined Time-Sensitive Networking</dc:title> <dc:creator>Binqi Li</dc:creator> <dc:creator>Yuan Zhu</dc:creator> <dc:creator>Qin Liu</dc:creator> <dc:creator>Xiangxi Yao</dc:creator> <dc:identifier>doi: 10.3390/machines12110816</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-15</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-15</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>816</prism:startingPage> <prism:doi>10.3390/machines12110816</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/816</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/815"> <title>Machines, Vol. 12, Pages 815: Sustainable Manufacturing and Green Processing Methods</title> <link>https://www.mdpi.com/2075-1702/12/11/815</link> <description>Sustainable manufacturing and green processing methods have gained immense relevance over recent years due to pressing concerns over environmental degradation, resource scarcity, and industrial waste [...]</description> <pubDate>2024-11-15</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 815: Sustainable Manufacturing and Green Processing Methods Machines <a href="https://www.mdpi.com/2075-1702/12/11/815">doi: 10.3390/machines12110815</a> Authors: Ali Khalfallah Carlos Leit茫o Sustainable manufacturing and green processing methods have gained immense relevance over recent years due to pressing concerns over environmental degradation, resource scarcity, and industrial waste [...] ]]></content:encoded> <dc:title>Sustainable Manufacturing and Green Processing Methods</dc:title> <dc:creator>Ali Khalfallah</dc:creator> <dc:creator>Carlos Leit茫o</dc:creator> <dc:identifier>doi: 10.3390/machines12110815</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-15</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-15</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Editorial</prism:section> <prism:startingPage>815</prism:startingPage> <prism:doi>10.3390/machines12110815</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/815</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/814"> <title>Machines, Vol. 12, Pages 814: Study on Comprehensive Performance of Four-Point Contact Ball Slewing Bearings Based on a Bearing Support Bolt-Integrated Model</title> <link>https://www.mdpi.com/2075-1702/12/11/814</link> <description>To investigate four-point contact ball slewing bearings, a bearing support bolt-integrated model was created with HyperMesh and ANSYS software, and its accuracy was theoretically confirmed. This study examines how the rolling element number Z, contact angle &amp;alpha;, bolt number N, bolt pre-tightening force coefficient P, and radial load-overturning moment angle &amp;theta; affect the comprehensive performance of four-point contact ball slewing bearings and connecting bolts. The study found that increasing Z, &amp;alpha;, N, P, and &amp;theta; reduces overall bearing, ring, rolling element, and contact load deformations. The maximum deformation and stress of bolts rise with P but decrease with Z, &amp;alpha;, N, and &amp;theta;. The degree of influence of each parameter on the deformation of the inner and outer rings, the deformation of the rolling element, and the contact load of the rolling body from large to small is ranked as follows: &amp;alpha;, N, Z, &amp;theta;, and P; the degree of influence on bolt deformation and bolt stress distribution uniformity from large to small is ranked as follows: N, &amp;alpha;, Z, &amp;theta;, and P; the degree of influence on the overall deformation of the bearing from large to small is ranked as follows: N, &amp;theta;, &amp;alpha;, Z and P; the degree of impact on the maximum stress of the bolt from large to small is ranked as follows: P, N, Z, &amp;alpha;, &amp;theta;. To improve the overall performance of a four-point contact ball slewing bearing, increase &amp;alpha;, N, Z, and &amp;theta;.</description> <pubDate>2024-11-15</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 814: Study on Comprehensive Performance of Four-Point Contact Ball Slewing Bearings Based on a Bearing Support Bolt-Integrated Model Machines <a href="https://www.mdpi.com/2075-1702/12/11/814">doi: 10.3390/machines12110814</a> Authors: Zhanshu He Zhenpeng Shi Dongchen Qin Jingbo Wen Jinggan Shao Xianghui Liu Xinghui Xie To investigate four-point contact ball slewing bearings, a bearing support bolt-integrated model was created with HyperMesh and ANSYS software, and its accuracy was theoretically confirmed. This study examines how the rolling element number Z, contact angle &amp;alpha;, bolt number N, bolt pre-tightening force coefficient P, and radial load-overturning moment angle &amp;theta; affect the comprehensive performance of four-point contact ball slewing bearings and connecting bolts. The study found that increasing Z, &amp;alpha;, N, P, and &amp;theta; reduces overall bearing, ring, rolling element, and contact load deformations. The maximum deformation and stress of bolts rise with P but decrease with Z, &amp;alpha;, N, and &amp;theta;. The degree of influence of each parameter on the deformation of the inner and outer rings, the deformation of the rolling element, and the contact load of the rolling body from large to small is ranked as follows: &amp;alpha;, N, Z, &amp;theta;, and P; the degree of influence on bolt deformation and bolt stress distribution uniformity from large to small is ranked as follows: N, &amp;alpha;, Z, &amp;theta;, and P; the degree of influence on the overall deformation of the bearing from large to small is ranked as follows: N, &amp;theta;, &amp;alpha;, Z and P; the degree of impact on the maximum stress of the bolt from large to small is ranked as follows: P, N, Z, &amp;alpha;, &amp;theta;. To improve the overall performance of a four-point contact ball slewing bearing, increase &amp;alpha;, N, Z, and &amp;theta;. ]]></content:encoded> <dc:title>Study on Comprehensive Performance of Four-Point Contact Ball Slewing Bearings Based on a Bearing Support Bolt-Integrated Model</dc:title> <dc:creator>Zhanshu He</dc:creator> <dc:creator>Zhenpeng Shi</dc:creator> <dc:creator>Dongchen Qin</dc:creator> <dc:creator>Jingbo Wen</dc:creator> <dc:creator>Jinggan Shao</dc:creator> <dc:creator>Xianghui Liu</dc:creator> <dc:creator>Xinghui Xie</dc:creator> <dc:identifier>doi: 10.3390/machines12110814</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-15</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-15</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>814</prism:startingPage> <prism:doi>10.3390/machines12110814</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/814</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/813"> <title>Machines, Vol. 12, Pages 813: Bio-Inspired Sinusoidal Metamaterials: Design, 4D Printing, Energy-Absorbing Properties</title> <link>https://www.mdpi.com/2075-1702/12/11/813</link> <description>Conventional energy-absorbing components have limited adjustability under complex working conditions. To overcome this limitation, we designed a bio-inspired sinusoidal metamaterial (BSM) inspired by the efficient energy-absorbing structure of the mantis shrimp jaw foot and 4D printed it based on shape-memory polymer (SMP). The effects of single-cell structural parameters and gradient design on its force&amp;ndash;displacement curves and energy-absorbing properties were explored. Based on the shape memory effect of SMP, the BSM can obtain arbitrary temporary shapes under the combined effect of temperature and force, realizing locally controllable compression deformation and programmable mechanical properties of the BSM structure. This research has a broad application prospect in the field of energy absorption and energy management and provides new ideas for the design of smart structural materials.</description> <pubDate>2024-11-15</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 813: Bio-Inspired Sinusoidal Metamaterials: Design, 4D Printing, Energy-Absorbing Properties Machines <a href="https://www.mdpi.com/2075-1702/12/11/813">doi: 10.3390/machines12110813</a> Authors: Jifeng Zhang Siwei Meng Baofeng Wang Ying Xu Guangfeng Shi Xueli Zhou Conventional energy-absorbing components have limited adjustability under complex working conditions. To overcome this limitation, we designed a bio-inspired sinusoidal metamaterial (BSM) inspired by the efficient energy-absorbing structure of the mantis shrimp jaw foot and 4D printed it based on shape-memory polymer (SMP). The effects of single-cell structural parameters and gradient design on its force&amp;ndash;displacement curves and energy-absorbing properties were explored. Based on the shape memory effect of SMP, the BSM can obtain arbitrary temporary shapes under the combined effect of temperature and force, realizing locally controllable compression deformation and programmable mechanical properties of the BSM structure. This research has a broad application prospect in the field of energy absorption and energy management and provides new ideas for the design of smart structural materials. ]]></content:encoded> <dc:title>Bio-Inspired Sinusoidal Metamaterials: Design, 4D Printing, Energy-Absorbing Properties</dc:title> <dc:creator>Jifeng Zhang</dc:creator> <dc:creator>Siwei Meng</dc:creator> <dc:creator>Baofeng Wang</dc:creator> <dc:creator>Ying Xu</dc:creator> <dc:creator>Guangfeng Shi</dc:creator> <dc:creator>Xueli Zhou</dc:creator> <dc:identifier>doi: 10.3390/machines12110813</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-15</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-15</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>813</prism:startingPage> <prism:doi>10.3390/machines12110813</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/813</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/812"> <title>Machines, Vol. 12, Pages 812: Analysis of Tire-Road Interaction: A Literature Review</title> <link>https://www.mdpi.com/2075-1702/12/11/812</link> <description>This paper presents a comprehensive literature review of the most popular and recent work on passenger and truck tires. Previous papers discuss a huge amount of work on the modeling of passenger car tires using finite element analysis. In addition, recent works on tire&amp;ndash;road interaction and the validation of tires using experimental measurements have been described. Moreover, the history of the tire-road contact algorithms is explained. In addition, friction modeling that is implemented in tire&amp;ndash;road interaction applications are discussed. Also, a summary of current state-of-the-art research work definitions and requirements of the tread rubber compound are covered from previous studies using various literature reviews and hyper-viscoelastic material models that are implemented for the tread top and the tread base rubber compound. Furthermore, the effect of tire temperature from previous works is presented here. Finally, this literature review also highlights the shortcomings of recent research work and describes the areas lacking in the literature.</description> <pubDate>2024-11-14</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 812: Analysis of Tire-Road Interaction: A Literature Review Machines <a href="https://www.mdpi.com/2075-1702/12/11/812">doi: 10.3390/machines12110812</a> Authors: Haniyeh Fathi Zeinab El-Sayegh Jing Ren Moustafa El-Gindy This paper presents a comprehensive literature review of the most popular and recent work on passenger and truck tires. Previous papers discuss a huge amount of work on the modeling of passenger car tires using finite element analysis. In addition, recent works on tire&amp;ndash;road interaction and the validation of tires using experimental measurements have been described. Moreover, the history of the tire-road contact algorithms is explained. In addition, friction modeling that is implemented in tire&amp;ndash;road interaction applications are discussed. Also, a summary of current state-of-the-art research work definitions and requirements of the tread rubber compound are covered from previous studies using various literature reviews and hyper-viscoelastic material models that are implemented for the tread top and the tread base rubber compound. Furthermore, the effect of tire temperature from previous works is presented here. Finally, this literature review also highlights the shortcomings of recent research work and describes the areas lacking in the literature. ]]></content:encoded> <dc:title>Analysis of Tire-Road Interaction: A Literature Review</dc:title> <dc:creator>Haniyeh Fathi</dc:creator> <dc:creator>Zeinab El-Sayegh</dc:creator> <dc:creator>Jing Ren</dc:creator> <dc:creator>Moustafa El-Gindy</dc:creator> <dc:identifier>doi: 10.3390/machines12110812</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-14</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-14</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Review</prism:section> <prism:startingPage>812</prism:startingPage> <prism:doi>10.3390/machines12110812</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/812</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/810"> <title>Machines, Vol. 12, Pages 810: Optimization of a Redundant Freedom Machining Toolpath for Scroll Profile Machining</title> <link>https://www.mdpi.com/2075-1702/12/11/810</link> <description>The scroll disc is a critical functional component of the scroll compression mechanism, and its machining precision and quality directly impact the performance and longevity of the compressor. Current machining methods for scroll profiles face challenges in simultaneously achieving wide applicability, high precision, and high efficiency. This paper addresses issues related to unsmooth toolpaths of machine tool axes and high acceleration in the rotary axis during redundant degrees of freedom scroll profile machining. This paper proposes a toolpath optimization method for redundant axes, with optimization objectives focused on reducing the counts of directional changes in the linear axes and smoothing the trajectories of all axes. Experimental results demonstrate that the proposed method offers higher machining efficiency compared to traditional polar coordinate machining.</description> <pubDate>2024-11-14</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 810: Optimization of a Redundant Freedom Machining Toolpath for Scroll Profile Machining Machines <a href="https://www.mdpi.com/2075-1702/12/11/810">doi: 10.3390/machines12110810</a> Authors: Song Gao Zifang Hu Huicheng Zhou Jiejun Xie Chenglei Zhang Xiaohan Zhang The scroll disc is a critical functional component of the scroll compression mechanism, and its machining precision and quality directly impact the performance and longevity of the compressor. Current machining methods for scroll profiles face challenges in simultaneously achieving wide applicability, high precision, and high efficiency. This paper addresses issues related to unsmooth toolpaths of machine tool axes and high acceleration in the rotary axis during redundant degrees of freedom scroll profile machining. This paper proposes a toolpath optimization method for redundant axes, with optimization objectives focused on reducing the counts of directional changes in the linear axes and smoothing the trajectories of all axes. Experimental results demonstrate that the proposed method offers higher machining efficiency compared to traditional polar coordinate machining. ]]></content:encoded> <dc:title>Optimization of a Redundant Freedom Machining Toolpath for Scroll Profile Machining</dc:title> <dc:creator>Song Gao</dc:creator> <dc:creator>Zifang Hu</dc:creator> <dc:creator>Huicheng Zhou</dc:creator> <dc:creator>Jiejun Xie</dc:creator> <dc:creator>Chenglei Zhang</dc:creator> <dc:creator>Xiaohan Zhang</dc:creator> <dc:identifier>doi: 10.3390/machines12110810</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-14</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-14</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>810</prism:startingPage> <prism:doi>10.3390/machines12110810</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/810</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/811"> <title>Machines, Vol. 12, Pages 811: Parallel&ndash;Serial Robotic Manipulators: A Review of Architectures, Applications, and Methods of Design and Analysis</title> <link>https://www.mdpi.com/2075-1702/12/11/811</link> <description>Parallel&amp;ndash;serial (hybrid) manipulators represent robotic systems composed of kinematic chains with parallel and serial structures. These manipulators combine the benefits of both parallel and serial mechanisms, such as increased stiffness, high positioning accuracy, and a large workspace. This study discusses the existing architectures and applications of parallel&amp;ndash;serial robots and the methods of their design and analysis. The paper reviews around 500 articles and presents over 150 architectures of manipulators used in machining, medicine, and pick-and-place tasks, humanoids and legged systems, haptic devices, simulators, and other applications, covering both lower mobility and kinematically redundant robots. After that, the paper considers how researchers have developed and analyzed these manipulators. In particular, it examines methods of type synthesis, mobility, kinematic, and dynamic analysis, workspace and singularity determination, performance evaluation, optimal design, control, and calibration. The review concludes with a discussion of current trends in the field of parallel&amp;ndash;serial manipulators and potential directions for future studies.</description> <pubDate>2024-11-14</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 811: Parallel&ndash;Serial Robotic Manipulators: A Review of Architectures, Applications, and Methods of Design and Analysis Machines <a href="https://www.mdpi.com/2075-1702/12/11/811">doi: 10.3390/machines12110811</a> Authors: Anton Antonov Parallel&amp;ndash;serial (hybrid) manipulators represent robotic systems composed of kinematic chains with parallel and serial structures. These manipulators combine the benefits of both parallel and serial mechanisms, such as increased stiffness, high positioning accuracy, and a large workspace. This study discusses the existing architectures and applications of parallel&amp;ndash;serial robots and the methods of their design and analysis. The paper reviews around 500 articles and presents over 150 architectures of manipulators used in machining, medicine, and pick-and-place tasks, humanoids and legged systems, haptic devices, simulators, and other applications, covering both lower mobility and kinematically redundant robots. After that, the paper considers how researchers have developed and analyzed these manipulators. In particular, it examines methods of type synthesis, mobility, kinematic, and dynamic analysis, workspace and singularity determination, performance evaluation, optimal design, control, and calibration. The review concludes with a discussion of current trends in the field of parallel&amp;ndash;serial manipulators and potential directions for future studies. ]]></content:encoded> <dc:title>Parallel&amp;ndash;Serial Robotic Manipulators: A Review of Architectures, Applications, and Methods of Design and Analysis</dc:title> <dc:creator>Anton Antonov</dc:creator> <dc:identifier>doi: 10.3390/machines12110811</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-14</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-14</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Review</prism:section> <prism:startingPage>811</prism:startingPage> <prism:doi>10.3390/machines12110811</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/811</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/809"> <title>Machines, Vol. 12, Pages 809: A Study on the Effect of Cutting Temperature on CFRP Hole Wall Damage in Continuous Drilling Process</title> <link>https://www.mdpi.com/2075-1702/12/11/809</link> <description>In the assembly process of aerospace parts, drilling is essential for carbon fiber-reinforced materials. However, due to the extreme thermal sensitivity of these composites, continuous drilling often leads to irreparable defects such as hole wall burns and exit delamination caused by concentrated cutting heat, resulting in the scrapping of parts. To address this issue, this paper explores the impact of temperature characteristics on drilling quality, providing guidance for optimizing the composite drilling process. A simulation model for single and continuous drilling was established to analyze the temperature distribution on the tool surface during drilling. A drilling temperature measurement system based on thin-film thermocouple technology was developed, enabling real-time online temperature monitoring. Continuous drilling experiments were conducted, analyzing the correlation between maximum drilling temperature and hole quality. Results show that temperatures from &amp;minus;25.75 &amp;deg;C to &amp;minus;9.75 &amp;deg;C and from 182 &amp;deg;C to 200.75 &amp;deg;C cause significant exit damage, while optimal hole quality is achieved between &amp;minus;1.25 &amp;deg;C and 168 &amp;deg;C.</description> <pubDate>2024-11-14</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 809: A Study on the Effect of Cutting Temperature on CFRP Hole Wall Damage in Continuous Drilling Process Machines <a href="https://www.mdpi.com/2075-1702/12/11/809">doi: 10.3390/machines12110809</a> Authors: Chong Zhang Feiyu Chen Dongxue Song Jiale Liu Qingsong Xu Qunli Zhou Haoyu Wang In the assembly process of aerospace parts, drilling is essential for carbon fiber-reinforced materials. However, due to the extreme thermal sensitivity of these composites, continuous drilling often leads to irreparable defects such as hole wall burns and exit delamination caused by concentrated cutting heat, resulting in the scrapping of parts. To address this issue, this paper explores the impact of temperature characteristics on drilling quality, providing guidance for optimizing the composite drilling process. A simulation model for single and continuous drilling was established to analyze the temperature distribution on the tool surface during drilling. A drilling temperature measurement system based on thin-film thermocouple technology was developed, enabling real-time online temperature monitoring. Continuous drilling experiments were conducted, analyzing the correlation between maximum drilling temperature and hole quality. Results show that temperatures from &amp;minus;25.75 &amp;deg;C to &amp;minus;9.75 &amp;deg;C and from 182 &amp;deg;C to 200.75 &amp;deg;C cause significant exit damage, while optimal hole quality is achieved between &amp;minus;1.25 &amp;deg;C and 168 &amp;deg;C. ]]></content:encoded> <dc:title>A Study on the Effect of Cutting Temperature on CFRP Hole Wall Damage in Continuous Drilling Process</dc:title> <dc:creator>Chong Zhang</dc:creator> <dc:creator>Feiyu Chen</dc:creator> <dc:creator>Dongxue Song</dc:creator> <dc:creator>Jiale Liu</dc:creator> <dc:creator>Qingsong Xu</dc:creator> <dc:creator>Qunli Zhou</dc:creator> <dc:creator>Haoyu Wang</dc:creator> <dc:identifier>doi: 10.3390/machines12110809</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-14</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-14</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>809</prism:startingPage> <prism:doi>10.3390/machines12110809</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/809</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/808"> <title>Machines, Vol. 12, Pages 808: Test Results and Considerations for Design Improvements of L-CADEL v.3 Elbow-Assisting Device</title> <link>https://www.mdpi.com/2075-1702/12/11/808</link> <description>The elbow-assisting device, L-CADEL, was analyzed by testing a prototype of design version three (v3) with the aim of discussing design improvements to solve problems and improve operational performance. The test results reported are from a lab testing campaign with 15 student volunteers from the engineering and physiotherapy disciplines. The main aspects of attention of the reported investigation are data analyses for motion diagnostics, comfort in wearing, operation efficiency, and the mechanical design of the arm platform and cable tensioning.</description> <pubDate>2024-11-14</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 808: Test Results and Considerations for Design Improvements of L-CADEL v.3 Elbow-Assisting Device Machines <a href="https://www.mdpi.com/2075-1702/12/11/808">doi: 10.3390/machines12110808</a> Authors: Marco Ceccarelli Sergei Kotov Earnest Ofonaike Matteo Russo The elbow-assisting device, L-CADEL, was analyzed by testing a prototype of design version three (v3) with the aim of discussing design improvements to solve problems and improve operational performance. The test results reported are from a lab testing campaign with 15 student volunteers from the engineering and physiotherapy disciplines. The main aspects of attention of the reported investigation are data analyses for motion diagnostics, comfort in wearing, operation efficiency, and the mechanical design of the arm platform and cable tensioning. ]]></content:encoded> <dc:title>Test Results and Considerations for Design Improvements of L-CADEL v.3 Elbow-Assisting Device</dc:title> <dc:creator>Marco Ceccarelli</dc:creator> <dc:creator>Sergei Kotov</dc:creator> <dc:creator>Earnest Ofonaike</dc:creator> <dc:creator>Matteo Russo</dc:creator> <dc:identifier>doi: 10.3390/machines12110808</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-14</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-14</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>808</prism:startingPage> <prism:doi>10.3390/machines12110808</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/808</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/807"> <title>Machines, Vol. 12, Pages 807: Improvement of Noise Reduction Structure of Direct-Acting Pressure Reducing Valve</title> <link>https://www.mdpi.com/2075-1702/12/11/807</link> <description>As a key pressure control component of a hydraulic system, the noise of the direct-acting pressure reducing valve affects the working state of the system directly. However, the existing pressure reducing valves generally have the problem of excessive pure noise. In order to solve this problem, this study explored various structural combinations with the aim of improving the noise level of a direct-acting pressure reducing valve. Firstly, the flow field model of the direct-acting pressure reducing valve was established by using FEA (Finite Element Analysis), and the relationship between the flow field state and noise state was demonstrated through CFD (Computational Fluid Dynamics) simulation. Secondly, the position, number, and diameter of the oil holes on the valve spool were comprehensively analyzed, and the sound field analysis using LMS Virtual Lab was carried out. Finally, a prototype of the pressure reducing valve was manufactured, and the noise level before and after improvement was compared. The results showed that the effective sound pressure after improvement was reduced by 6.1% compared with that before at 50% of the opening, which verified the precision of the simulation model. The research results could provide a guideline for the design and improvement of direct-acting pressure reducing valves.</description> <pubDate>2024-11-14</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 807: Improvement of Noise Reduction Structure of Direct-Acting Pressure Reducing Valve Machines <a href="https://www.mdpi.com/2075-1702/12/11/807">doi: 10.3390/machines12110807</a> Authors: Rongsheng Liu Baosheng Wang Rongren Wang Liu Yang Lihui Wang Chao Ai As a key pressure control component of a hydraulic system, the noise of the direct-acting pressure reducing valve affects the working state of the system directly. However, the existing pressure reducing valves generally have the problem of excessive pure noise. In order to solve this problem, this study explored various structural combinations with the aim of improving the noise level of a direct-acting pressure reducing valve. Firstly, the flow field model of the direct-acting pressure reducing valve was established by using FEA (Finite Element Analysis), and the relationship between the flow field state and noise state was demonstrated through CFD (Computational Fluid Dynamics) simulation. Secondly, the position, number, and diameter of the oil holes on the valve spool were comprehensively analyzed, and the sound field analysis using LMS Virtual Lab was carried out. Finally, a prototype of the pressure reducing valve was manufactured, and the noise level before and after improvement was compared. The results showed that the effective sound pressure after improvement was reduced by 6.1% compared with that before at 50% of the opening, which verified the precision of the simulation model. The research results could provide a guideline for the design and improvement of direct-acting pressure reducing valves. ]]></content:encoded> <dc:title>Improvement of Noise Reduction Structure of Direct-Acting Pressure Reducing Valve</dc:title> <dc:creator>Rongsheng Liu</dc:creator> <dc:creator>Baosheng Wang</dc:creator> <dc:creator>Rongren Wang</dc:creator> <dc:creator>Liu Yang</dc:creator> <dc:creator>Lihui Wang</dc:creator> <dc:creator>Chao Ai</dc:creator> <dc:identifier>doi: 10.3390/machines12110807</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-14</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-14</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>807</prism:startingPage> <prism:doi>10.3390/machines12110807</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/807</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/806"> <title>Machines, Vol. 12, Pages 806: Self-Starting Improvement and Performance Enhancement in Darrieus VAWTs Using Auxiliary Blades and Deflectors</title> <link>https://www.mdpi.com/2075-1702/12/11/806</link> <description>The Darrieus vertical axis wind turbine (VAWT) is categorized as a lift-based turbomachine. It faces challenges in the low tip speed ratio (TSR) range and requires initial torque for the starting operation. Ongoing efforts are being made to enhance the turbine&amp;rsquo;s self-starting capability. In this study, Computational Fluid Dynamics (CFD) simulations were utilized to tackle the identified challenge. The Unsteady Reynolds-Averaged Navier&amp;ndash;Stokes (URANS) approach was employed, combined with the shear&amp;ndash;stress transport (SST) k&amp;minus;&amp;omega; turbulence model, to resolve fluid flow equations. The investigation focused on optimizing the placement of auxiliary blades by considering design parameters such as the pitch angle and horizontal and vertical distances. The goal was to increase the turbine efficiency and initial torque in the low-TSR range while minimizing efficiency loss at high-TSR ranges, which is the primary challenge of auxiliary blade installation. Implementing the auxiliary blade successfully extended the rotor&amp;rsquo;s operational range, shifting the rotor operation&amp;rsquo;s onset from TSR 1.4 to 0.7. The optimal configuration for installing the auxiliary blade involves a pitch angle of 0&amp;deg;, a horizontal ratio of 0.52, and a vertical ratio of 0.41. To address the ineffectiveness of auxiliary blades at high-TSRs, installing deflectors in various configurations was explored. Introducing a double deflector can significantly enhance the overall efficiency of the conventional Darrieus VAWT and the optimum rotor with the auxiliary blade by 47% and 73% at TSR = 2.5, respectively.</description> <pubDate>2024-11-14</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 806: Self-Starting Improvement and Performance Enhancement in Darrieus VAWTs Using Auxiliary Blades and Deflectors Machines <a href="https://www.mdpi.com/2075-1702/12/11/806">doi: 10.3390/machines12110806</a> Authors: Farzad Ghafoorian Erfan Enayati Seyed Reza Mirmotahari Hui Wan The Darrieus vertical axis wind turbine (VAWT) is categorized as a lift-based turbomachine. It faces challenges in the low tip speed ratio (TSR) range and requires initial torque for the starting operation. Ongoing efforts are being made to enhance the turbine&amp;rsquo;s self-starting capability. In this study, Computational Fluid Dynamics (CFD) simulations were utilized to tackle the identified challenge. The Unsteady Reynolds-Averaged Navier&amp;ndash;Stokes (URANS) approach was employed, combined with the shear&amp;ndash;stress transport (SST) k&amp;minus;&amp;omega; turbulence model, to resolve fluid flow equations. The investigation focused on optimizing the placement of auxiliary blades by considering design parameters such as the pitch angle and horizontal and vertical distances. The goal was to increase the turbine efficiency and initial torque in the low-TSR range while minimizing efficiency loss at high-TSR ranges, which is the primary challenge of auxiliary blade installation. Implementing the auxiliary blade successfully extended the rotor&amp;rsquo;s operational range, shifting the rotor operation&amp;rsquo;s onset from TSR 1.4 to 0.7. The optimal configuration for installing the auxiliary blade involves a pitch angle of 0&amp;deg;, a horizontal ratio of 0.52, and a vertical ratio of 0.41. To address the ineffectiveness of auxiliary blades at high-TSRs, installing deflectors in various configurations was explored. Introducing a double deflector can significantly enhance the overall efficiency of the conventional Darrieus VAWT and the optimum rotor with the auxiliary blade by 47% and 73% at TSR = 2.5, respectively. ]]></content:encoded> <dc:title>Self-Starting Improvement and Performance Enhancement in Darrieus VAWTs Using Auxiliary Blades and Deflectors</dc:title> <dc:creator>Farzad Ghafoorian</dc:creator> <dc:creator>Erfan Enayati</dc:creator> <dc:creator>Seyed Reza Mirmotahari</dc:creator> <dc:creator>Hui Wan</dc:creator> <dc:identifier>doi: 10.3390/machines12110806</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-14</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-14</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>806</prism:startingPage> <prism:doi>10.3390/machines12110806</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/806</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/805"> <title>Machines, Vol. 12, Pages 805: Classification-Based Parameter Optimization Approach of the Turning Process</title> <link>https://www.mdpi.com/2075-1702/12/11/805</link> <description>The turning process is a widely used machining process, and its productivity has a significant impact on the cost and profit in industrial enterprises. Currently, it is difficult to effectively determine the optimum process parameters under complex conditions. To address this issue, a classification-based parameter optimization approach of the turning process is proposed in this paper, which aims to provide feasible optimization suggestions of process parameters and consists of a classification model and several optimization strategies. Specifically, the classification model is used to separate the whole complex process into different substages to reduce difficulties of the further optimization, and it achieves high accuracy and strong anti-interference in the identification of substages by integrating the advantages of an encoder-decoder framework, attention mechanism, and major voting. Additionally, during the optimization process of each substage, Dynamic Time Warping (DTW) and K-Nearest Neighbor (KNN) are utilized to eliminate the negative impact of cutting tool wear status on optimization results at first. Then, the envelope curve strategy and boxplot method succeed in the adaptive calculation of a parameter threshold and the detection of optimizable items. According to these optimization strategies, the proposed approach performs well in the provision of effective optimization suggestions. Ultimately, the proposed approach is verified by a bearing production line. Experimental results demonstrate that the proposed approach achieves a significant productivity improvement of 23.43% in the studied production line.</description> <pubDate>2024-11-13</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 805: Classification-Based Parameter Optimization Approach of the Turning Process Machines <a href="https://www.mdpi.com/2075-1702/12/11/805">doi: 10.3390/machines12110805</a> Authors: Lei Yang Yibo Jiang Yawei Yang Guowen Zeng Zongzhi Zhu Jiaxi Chen The turning process is a widely used machining process, and its productivity has a significant impact on the cost and profit in industrial enterprises. Currently, it is difficult to effectively determine the optimum process parameters under complex conditions. To address this issue, a classification-based parameter optimization approach of the turning process is proposed in this paper, which aims to provide feasible optimization suggestions of process parameters and consists of a classification model and several optimization strategies. Specifically, the classification model is used to separate the whole complex process into different substages to reduce difficulties of the further optimization, and it achieves high accuracy and strong anti-interference in the identification of substages by integrating the advantages of an encoder-decoder framework, attention mechanism, and major voting. Additionally, during the optimization process of each substage, Dynamic Time Warping (DTW) and K-Nearest Neighbor (KNN) are utilized to eliminate the negative impact of cutting tool wear status on optimization results at first. Then, the envelope curve strategy and boxplot method succeed in the adaptive calculation of a parameter threshold and the detection of optimizable items. According to these optimization strategies, the proposed approach performs well in the provision of effective optimization suggestions. Ultimately, the proposed approach is verified by a bearing production line. Experimental results demonstrate that the proposed approach achieves a significant productivity improvement of 23.43% in the studied production line. ]]></content:encoded> <dc:title>Classification-Based Parameter Optimization Approach of the Turning Process</dc:title> <dc:creator>Lei Yang</dc:creator> <dc:creator>Yibo Jiang</dc:creator> <dc:creator>Yawei Yang</dc:creator> <dc:creator>Guowen Zeng</dc:creator> <dc:creator>Zongzhi Zhu</dc:creator> <dc:creator>Jiaxi Chen</dc:creator> <dc:identifier>doi: 10.3390/machines12110805</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-13</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-13</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>805</prism:startingPage> <prism:doi>10.3390/machines12110805</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/805</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/804"> <title>Machines, Vol. 12, Pages 804: Solar Irradiance Prediction Method for PV Power Supply System of Mobile Sprinkler Machine Using WOA-XGBoost Model</title> <link>https://www.mdpi.com/2075-1702/12/11/804</link> <description>Solar energy can mitigate the power supply shortage in remote regions for portable irrigation systems. The accurate prediction of solar irradiance is crucial for determining the power capacity of photovoltaic power generation (PVPG) systems for mobile sprinkler machines. In this study, a prediction method is proposed to estimate the solar irradiance of typical irrigation areas. The relation between meteorological parameters and solar irradiance is studied, and four different parameter combinations are formed and considered as inputs to the prediction model. Based on meteorological data provided by ten typical radiation stations uniformly distributed nationwide, an Extreme Gradient Boosting (XGBoost) model optimized using the Whale Optimization Algorithm (WOA) is developed to predict solar radiation. The prediction accuracy and stability of the proposed method are then evaluated for different input parameters through training and testing. The differences between the prediction performances of models trained based on single-station data and mixed data from multiple stations are also compared. The obtained results show that the proposed model achieves the highest prediction accuracy when the maximum temperature, minimum temperature, sunshine hours ratio, relative humidity, wind speed, and extraterrestrial radiation are used as input parameters. In the model testing, the RMSE and MAE of WOA-XGBoost are 2.142 MJ&amp;middot;m&amp;minus;2&amp;middot;d&amp;minus;1 and 1.531 MJ&amp;middot;m&amp;minus;2&amp;middot;d&amp;minus;1, respectively, while those of XGBoost are 2.298 MJ&amp;middot;m&amp;minus;2&amp;middot;d&amp;minus;1 and 1.598 MJ&amp;middot;m&amp;minus;2&amp;middot;d&amp;minus;1. The prediction effectiveness is also verified based on measured data. The WOA-XGBoost model has higher prediction accuracy than the XGBoost model. The model developed in this study can be applied to forecast solar irradiance in different regions. By inputting the meteorological parameter data specific to a given area, this model can effectively produce accurate solar irradiance predictions for that region. This study provides a foundation for the optimization of the configuration of PVPG systems for mobile sprinkler machines.</description> <pubDate>2024-11-13</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 804: Solar Irradiance Prediction Method for PV Power Supply System of Mobile Sprinkler Machine Using WOA-XGBoost Model Machines <a href="https://www.mdpi.com/2075-1702/12/11/804">doi: 10.3390/machines12110804</a> Authors: Dan Li Jiwei Qu Delan Zhu Zheyu Qin Solar energy can mitigate the power supply shortage in remote regions for portable irrigation systems. The accurate prediction of solar irradiance is crucial for determining the power capacity of photovoltaic power generation (PVPG) systems for mobile sprinkler machines. In this study, a prediction method is proposed to estimate the solar irradiance of typical irrigation areas. The relation between meteorological parameters and solar irradiance is studied, and four different parameter combinations are formed and considered as inputs to the prediction model. Based on meteorological data provided by ten typical radiation stations uniformly distributed nationwide, an Extreme Gradient Boosting (XGBoost) model optimized using the Whale Optimization Algorithm (WOA) is developed to predict solar radiation. The prediction accuracy and stability of the proposed method are then evaluated for different input parameters through training and testing. The differences between the prediction performances of models trained based on single-station data and mixed data from multiple stations are also compared. The obtained results show that the proposed model achieves the highest prediction accuracy when the maximum temperature, minimum temperature, sunshine hours ratio, relative humidity, wind speed, and extraterrestrial radiation are used as input parameters. In the model testing, the RMSE and MAE of WOA-XGBoost are 2.142 MJ&amp;middot;m&amp;minus;2&amp;middot;d&amp;minus;1 and 1.531 MJ&amp;middot;m&amp;minus;2&amp;middot;d&amp;minus;1, respectively, while those of XGBoost are 2.298 MJ&amp;middot;m&amp;minus;2&amp;middot;d&amp;minus;1 and 1.598 MJ&amp;middot;m&amp;minus;2&amp;middot;d&amp;minus;1. The prediction effectiveness is also verified based on measured data. The WOA-XGBoost model has higher prediction accuracy than the XGBoost model. The model developed in this study can be applied to forecast solar irradiance in different regions. By inputting the meteorological parameter data specific to a given area, this model can effectively produce accurate solar irradiance predictions for that region. This study provides a foundation for the optimization of the configuration of PVPG systems for mobile sprinkler machines. ]]></content:encoded> <dc:title>Solar Irradiance Prediction Method for PV Power Supply System of Mobile Sprinkler Machine Using WOA-XGBoost Model</dc:title> <dc:creator>Dan Li</dc:creator> <dc:creator>Jiwei Qu</dc:creator> <dc:creator>Delan Zhu</dc:creator> <dc:creator>Zheyu Qin</dc:creator> <dc:identifier>doi: 10.3390/machines12110804</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-13</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-13</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>804</prism:startingPage> <prism:doi>10.3390/machines12110804</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/804</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/803"> <title>Machines, Vol. 12, Pages 803: Use of Distributed Energy Resources Integrated with the Electric Grid in the Amazon: A Case Study of the Universidade Federal do Par&aacute; Poraqu&ecirc; Electric Boat Using a Digital Twin</title> <link>https://www.mdpi.com/2075-1702/12/11/803</link> <description>Electric mobility is a global trend and necessity, with electric and solar boats offering a promising alternative for transportation electrification and carbon emission reduction, especially in the Amazon region. This study analyzes the system of a solar boat from an electric mobility project&amp;mdash;to be implemented at Universidade Federal do Par&amp;aacute; (UFPA)&amp;mdash;using MATLAB software for modeling. The Simulink tool was utilized to model the system, focusing on operational parameters such as module voltage, converter voltage, and speed. The results indicate that the solar boat&amp;rsquo;s operational cost is significantly lower compared to a similar internal combustion model, considering diesel&amp;rsquo;s high consumption and cost. The environmental impact is also reduced, with nearly 72 tons of CO2 emissions avoided annually, thanks to Brazil&amp;rsquo;s renewable energy matrix. Simulations confirmed the project&amp;rsquo;s parameters, demonstrating the efficiency of digital-twin technology in monitoring and predicting system performance. The study underscores the importance of digital twins and renewable energy in promoting sustainable transportation solutions, advocating for the replication of such projects globally. Future research should focus on further advancing digital-twin applications in electric mobility to enhance predictive maintenance and operational efficiency.</description> <pubDate>2024-11-12</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 803: Use of Distributed Energy Resources Integrated with the Electric Grid in the Amazon: A Case Study of the Universidade Federal do Par&aacute; Poraqu&ecirc; Electric Boat Using a Digital Twin Machines <a href="https://www.mdpi.com/2075-1702/12/11/803">doi: 10.3390/machines12110803</a> Authors: Bruno Santana de Albuquerque Maria Em铆lia de Lima Tostes Ubiratan Holanda Bezerra Carminda C茅lia Moura de Moura Carvalho Ayrton Lucas Lisboa do Nascimento Electric mobility is a global trend and necessity, with electric and solar boats offering a promising alternative for transportation electrification and carbon emission reduction, especially in the Amazon region. This study analyzes the system of a solar boat from an electric mobility project&amp;mdash;to be implemented at Universidade Federal do Par&amp;aacute; (UFPA)&amp;mdash;using MATLAB software for modeling. The Simulink tool was utilized to model the system, focusing on operational parameters such as module voltage, converter voltage, and speed. The results indicate that the solar boat&amp;rsquo;s operational cost is significantly lower compared to a similar internal combustion model, considering diesel&amp;rsquo;s high consumption and cost. The environmental impact is also reduced, with nearly 72 tons of CO2 emissions avoided annually, thanks to Brazil&amp;rsquo;s renewable energy matrix. Simulations confirmed the project&amp;rsquo;s parameters, demonstrating the efficiency of digital-twin technology in monitoring and predicting system performance. The study underscores the importance of digital twins and renewable energy in promoting sustainable transportation solutions, advocating for the replication of such projects globally. Future research should focus on further advancing digital-twin applications in electric mobility to enhance predictive maintenance and operational efficiency. ]]></content:encoded> <dc:title>Use of Distributed Energy Resources Integrated with the Electric Grid in the Amazon: A Case Study of the Universidade Federal do Par&amp;aacute; Poraqu&amp;ecirc; Electric Boat Using a Digital Twin</dc:title> <dc:creator>Bruno Santana de Albuquerque</dc:creator> <dc:creator>Maria Em铆lia de Lima Tostes</dc:creator> <dc:creator>Ubiratan Holanda Bezerra</dc:creator> <dc:creator>Carminda C茅lia Moura de Moura Carvalho</dc:creator> <dc:creator>Ayrton Lucas Lisboa do Nascimento</dc:creator> <dc:identifier>doi: 10.3390/machines12110803</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-12</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-12</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>803</prism:startingPage> <prism:doi>10.3390/machines12110803</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/803</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/802"> <title>Machines, Vol. 12, Pages 802: Smooth and Time-Optimal Trajectory Planning for Robots Using Improved Carnivorous Plant Algorithm</title> <link>https://www.mdpi.com/2075-1702/12/11/802</link> <description>To improve the safety and reliability of robotic manipulators during high-speed precision movements, this paper proposes a method for smooth and time-optimal trajectory planning incorporating kinodynamic constraints. The primary objective is to use an evolutionary algorithm to determine a trajectory by considering time and jerk within the feasible path-pseudo-velocity phase plane region. Firstly, the path parameterization theory extracted the maximum pseudo-velocity projection curve from the kinodynamic constraints. Subsequently, the feasible region in the phase plane was defined through reachability analysis of discrete linear systems. Thereafter, we constructed the trajectory function using a cubic B-spline curve, optimizing its control points with an improved carnivorous plant optimization algorithm. Finally, the effectiveness and practicality of this method were verified through simulations on a 6-DOF manipulator.</description> <pubDate>2024-11-12</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 802: Smooth and Time-Optimal Trajectory Planning for Robots Using Improved Carnivorous Plant Algorithm Machines <a href="https://www.mdpi.com/2075-1702/12/11/802">doi: 10.3390/machines12110802</a> Authors: Bo Wei Changyi Liu Xin Zhang Kai Zheng Zhengfeng Cao Zexin Chen To improve the safety and reliability of robotic manipulators during high-speed precision movements, this paper proposes a method for smooth and time-optimal trajectory planning incorporating kinodynamic constraints. The primary objective is to use an evolutionary algorithm to determine a trajectory by considering time and jerk within the feasible path-pseudo-velocity phase plane region. Firstly, the path parameterization theory extracted the maximum pseudo-velocity projection curve from the kinodynamic constraints. Subsequently, the feasible region in the phase plane was defined through reachability analysis of discrete linear systems. Thereafter, we constructed the trajectory function using a cubic B-spline curve, optimizing its control points with an improved carnivorous plant optimization algorithm. Finally, the effectiveness and practicality of this method were verified through simulations on a 6-DOF manipulator. ]]></content:encoded> <dc:title>Smooth and Time-Optimal Trajectory Planning for Robots Using Improved Carnivorous Plant Algorithm</dc:title> <dc:creator>Bo Wei</dc:creator> <dc:creator>Changyi Liu</dc:creator> <dc:creator>Xin Zhang</dc:creator> <dc:creator>Kai Zheng</dc:creator> <dc:creator>Zhengfeng Cao</dc:creator> <dc:creator>Zexin Chen</dc:creator> <dc:identifier>doi: 10.3390/machines12110802</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-12</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-12</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>802</prism:startingPage> <prism:doi>10.3390/machines12110802</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/802</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/801"> <title>Machines, Vol. 12, Pages 801: Adaptive Multi-Scale Bayesian Framework for MFL Inspection of Steel Wire Ropes</title> <link>https://www.mdpi.com/2075-1702/12/11/801</link> <description>Magnetic flux leakage (MFL) technology is widely used in steel wire rope (SWR) inspection for non-destructive testing. However, accurate defect characterization requires advanced signal processing techniques to handle complex noise conditions and varying defect types. This paper presents a novel adaptive multi-scale Bayesian framework for MFL signal analysis in SWR inspection. Our approach integrates discrete wavelet transform with adaptive thresholding and multi-scale feature fusion, enabling simultaneous detection of minute defects and large-area corrosion. To validate our method, we implemented a four-channel MFL detection system and conducted extensive experiments on both simulated and real-world datasets. Compared with state-of-the-art methods, including long short-term memory (LSTM), attention mechanisms, and isolation forests, our approach demonstrated significant improvements in precision, recall, and F1 score across various tolerance levels. The proposed method showed superior detection performance, with an average precision of 91%, recall of 89%, and an F1 score of 0.90 in high-noise conditions, surpassing existing techniques. Notably, our method showed superior performance in high-noise environments, reducing false positive rates while maintaining high detection sensitivity. While computational complexity in real-time processing remains a challenge, this study provides a robust solution for non-destructive testing of SWR, potentially improving inspection efficiency and defect localization accuracy. Future work will focus on optimizing algorithmic efficiency and exploring transfer learning techniques for enhanced adaptability across different non-destructive testing (NDT) domains. This research not only advances signal processing and anomaly detection technology but also contributes to enhancing safety and maintenance efficiency in critical infrastructure.</description> <pubDate>2024-11-12</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 801: Adaptive Multi-Scale Bayesian Framework for MFL Inspection of Steel Wire Ropes Machines <a href="https://www.mdpi.com/2075-1702/12/11/801">doi: 10.3390/machines12110801</a> Authors: Xiaoping Li Yujie Sun Xinyue Liu Shaoxuan Zhang Magnetic flux leakage (MFL) technology is widely used in steel wire rope (SWR) inspection for non-destructive testing. However, accurate defect characterization requires advanced signal processing techniques to handle complex noise conditions and varying defect types. This paper presents a novel adaptive multi-scale Bayesian framework for MFL signal analysis in SWR inspection. Our approach integrates discrete wavelet transform with adaptive thresholding and multi-scale feature fusion, enabling simultaneous detection of minute defects and large-area corrosion. To validate our method, we implemented a four-channel MFL detection system and conducted extensive experiments on both simulated and real-world datasets. Compared with state-of-the-art methods, including long short-term memory (LSTM), attention mechanisms, and isolation forests, our approach demonstrated significant improvements in precision, recall, and F1 score across various tolerance levels. The proposed method showed superior detection performance, with an average precision of 91%, recall of 89%, and an F1 score of 0.90 in high-noise conditions, surpassing existing techniques. Notably, our method showed superior performance in high-noise environments, reducing false positive rates while maintaining high detection sensitivity. While computational complexity in real-time processing remains a challenge, this study provides a robust solution for non-destructive testing of SWR, potentially improving inspection efficiency and defect localization accuracy. Future work will focus on optimizing algorithmic efficiency and exploring transfer learning techniques for enhanced adaptability across different non-destructive testing (NDT) domains. This research not only advances signal processing and anomaly detection technology but also contributes to enhancing safety and maintenance efficiency in critical infrastructure. ]]></content:encoded> <dc:title>Adaptive Multi-Scale Bayesian Framework for MFL Inspection of Steel Wire Ropes</dc:title> <dc:creator>Xiaoping Li</dc:creator> <dc:creator>Yujie Sun</dc:creator> <dc:creator>Xinyue Liu</dc:creator> <dc:creator>Shaoxuan Zhang</dc:creator> <dc:identifier>doi: 10.3390/machines12110801</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-12</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-12</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>801</prism:startingPage> <prism:doi>10.3390/machines12110801</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/801</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/800"> <title>Machines, Vol. 12, Pages 800: CFD Analysis on Novel Vertical Axis Wind Turbine (VAWT)</title> <link>https://www.mdpi.com/2075-1702/12/11/800</link> <description>The operation of vertical axis wind turbines (VAWTs) to generate low-carbon electricity is growing in popularity. Their advantages over the widely used horizontal axis wind turbine (HAWT) include their low tip speed, which reduces noise, and their cost-effective installation and maintenance. A Farrah turbine equipped with 12 blades was designed to enhance performance and was recently the subject of experimental investigation. However, little research has been focused on turbine configurations with more than three blades. The objective of this study is to employ numerical methods to analyse the performance of the Farrah wind turbine and to validate the findings in comparison with experimental results. The investigated blade pitch angles included both positive and negative angles of 7, 15, 20 and 40 degrees. The k-&amp;omega; SST model with the sliding mesh technique was used to perform simulations of a 14.4 million element unstructured mesh. Comparable trends of power output results in the experimental investigation were obtained and the assumptions of mechanical losses discussed. Wake recovery was determined at an approximate distance of nine times the turbine diameter. Two large complex quasi-symmetric vortical structures were observed between positive and negative blade pitch angles, located in the near wake region of the turbine and remaining present throughout its rotation. It is demonstrated that a number of recognised vortical structures are transferred towards the wake region, further contributing to its formation. Additional notable vortical formations are examined, along with a recirculation zone located in the turbine&amp;rsquo;s core, which is described to exhibit quasi-symmetric behaviour between positive and negative rotations.</description> <pubDate>2024-11-12</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 800: CFD Analysis on Novel Vertical Axis Wind Turbine (VAWT) Machines <a href="https://www.mdpi.com/2075-1702/12/11/800">doi: 10.3390/machines12110800</a> Authors: Chris Sungkyun Bang Zeeshan A. Rana Simon A. Prince The operation of vertical axis wind turbines (VAWTs) to generate low-carbon electricity is growing in popularity. Their advantages over the widely used horizontal axis wind turbine (HAWT) include their low tip speed, which reduces noise, and their cost-effective installation and maintenance. A Farrah turbine equipped with 12 blades was designed to enhance performance and was recently the subject of experimental investigation. However, little research has been focused on turbine configurations with more than three blades. The objective of this study is to employ numerical methods to analyse the performance of the Farrah wind turbine and to validate the findings in comparison with experimental results. The investigated blade pitch angles included both positive and negative angles of 7, 15, 20 and 40 degrees. The k-&amp;omega; SST model with the sliding mesh technique was used to perform simulations of a 14.4 million element unstructured mesh. Comparable trends of power output results in the experimental investigation were obtained and the assumptions of mechanical losses discussed. Wake recovery was determined at an approximate distance of nine times the turbine diameter. Two large complex quasi-symmetric vortical structures were observed between positive and negative blade pitch angles, located in the near wake region of the turbine and remaining present throughout its rotation. It is demonstrated that a number of recognised vortical structures are transferred towards the wake region, further contributing to its formation. Additional notable vortical formations are examined, along with a recirculation zone located in the turbine&amp;rsquo;s core, which is described to exhibit quasi-symmetric behaviour between positive and negative rotations. ]]></content:encoded> <dc:title>CFD Analysis on Novel Vertical Axis Wind Turbine (VAWT)</dc:title> <dc:creator>Chris Sungkyun Bang</dc:creator> <dc:creator>Zeeshan A. Rana</dc:creator> <dc:creator>Simon A. Prince</dc:creator> <dc:identifier>doi: 10.3390/machines12110800</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-12</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-12</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>800</prism:startingPage> <prism:doi>10.3390/machines12110800</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/800</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/798"> <title>Machines, Vol. 12, Pages 798: Ensuring Driving and Road Safety of Autonomous Vehicles Using a Control Optimiser Interaction Framework Through Smart &ldquo;Thing&rdquo; Information Sensing and Actuation</title> <link>https://www.mdpi.com/2075-1702/12/11/798</link> <description>Road safety through point-to-point interaction autonomous vehicles (AVs) assimilate different communication technologies for reliable and persistent information sharing. Vehicle interaction resilience and consistency require novel sharing knowledge for retaining driving and pedestrian safety. This article proposes a control optimiser interaction framework (COIF) for organising information transmission between the AV and interacting &amp;ldquo;Thing&amp;rdquo;. The framework relies on the neuro-batch learning algorithm to improve the consistency measure&amp;rsquo;s adaptability with the interacting &amp;ldquo;Things&amp;rdquo;. In the information-sharing process, the maximum extraction and utilisation are computed to track the AV with precise environmental knowledge. The interactions are batched with the type of traffic information obtained, such as population, accidents, objects, hindrances, etc. Throughout travel, the vehicle&amp;rsquo;s learning rate and the surrounding environment&amp;rsquo;s familiarity with it are classified. The learning neurons are connected to the information actuated and sensed by the AV to identify any unsafe vehicle activity in unknown or unidentified scenarios. Based on the risk and driving parameters, the safe and unsafe activity of the vehicles is categorised with a precise learning rate. Therefore, minor changes in vehicular decisions are monitored, and driving control is optimised accordingly to retain 7.93% of navigation assistance through a 9.76% high learning rate for different intervals.</description> <pubDate>2024-11-11</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 798: Ensuring Driving and Road Safety of Autonomous Vehicles Using a Control Optimiser Interaction Framework Through Smart &ldquo;Thing&rdquo; Information Sensing and Actuation Machines <a href="https://www.mdpi.com/2075-1702/12/11/798">doi: 10.3390/machines12110798</a> Authors: Ahmed Almutairi Abdullah Faiz Al Asmari Tariq Alqubaysi Fayez Alanazi Ammar Armghan Road safety through point-to-point interaction autonomous vehicles (AVs) assimilate different communication technologies for reliable and persistent information sharing. Vehicle interaction resilience and consistency require novel sharing knowledge for retaining driving and pedestrian safety. This article proposes a control optimiser interaction framework (COIF) for organising information transmission between the AV and interacting &amp;ldquo;Thing&amp;rdquo;. The framework relies on the neuro-batch learning algorithm to improve the consistency measure&amp;rsquo;s adaptability with the interacting &amp;ldquo;Things&amp;rdquo;. In the information-sharing process, the maximum extraction and utilisation are computed to track the AV with precise environmental knowledge. The interactions are batched with the type of traffic information obtained, such as population, accidents, objects, hindrances, etc. Throughout travel, the vehicle&amp;rsquo;s learning rate and the surrounding environment&amp;rsquo;s familiarity with it are classified. The learning neurons are connected to the information actuated and sensed by the AV to identify any unsafe vehicle activity in unknown or unidentified scenarios. Based on the risk and driving parameters, the safe and unsafe activity of the vehicles is categorised with a precise learning rate. Therefore, minor changes in vehicular decisions are monitored, and driving control is optimised accordingly to retain 7.93% of navigation assistance through a 9.76% high learning rate for different intervals. ]]></content:encoded> <dc:title>Ensuring Driving and Road Safety of Autonomous Vehicles Using a Control Optimiser Interaction Framework Through Smart &amp;ldquo;Thing&amp;rdquo; Information Sensing and Actuation</dc:title> <dc:creator>Ahmed Almutairi</dc:creator> <dc:creator>Abdullah Faiz Al Asmari</dc:creator> <dc:creator>Tariq Alqubaysi</dc:creator> <dc:creator>Fayez Alanazi</dc:creator> <dc:creator>Ammar Armghan</dc:creator> <dc:identifier>doi: 10.3390/machines12110798</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-11</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-11</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>798</prism:startingPage> <prism:doi>10.3390/machines12110798</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/798</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/799"> <title>Machines, Vol. 12, Pages 799: Parameter Optimization Method for Centrifugal Feed Disc Discharging Based on Numerical Simulation and Response Surface</title> <link>https://www.mdpi.com/2075-1702/12/11/799</link> <description>In this study, a centrifugal feeding disc device is proposed. To investigate the influence of the process parameters on the discharging efficiency and the lifting of the discharging efficiency, the centrifugal feeding disc device was dynamically simulated based on the discrete element method (DEM), and the simulation results were experimentally verified. Based on the quadratic regression orthogonal test method, a significant lossless regression model of process parameters and discharging efficiency was established, and the response surface of the interaction of process parameters was obtained. The results indicated that the order of influence of the process parameters on the discharging speed of the centrifugal feeding disc was as follows: outer turntable speed &amp;gt; inner turntable speed &amp;gt; inner turntable tilt angle &amp;gt; conical turntable angle. The interaction of the conical turntable angle and the inner turntable tilt angle had the greatest influence on the centrifugal feed disc discharge efficiency. The response surface method (RSM) was used to optimize the process parameters, and the optimal combination of process parameters included an outer turntable speed of 135 r/min, an inner turntable speed of 64 r/min, an inner turntable tilt angle of 7&amp;deg;, and a conical angle of 15&amp;deg;. The discharged efficiency of the optimized centrifugal feeding disc device was increased by 31.9%.</description> <pubDate>2024-11-11</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 799: Parameter Optimization Method for Centrifugal Feed Disc Discharging Based on Numerical Simulation and Response Surface Machines <a href="https://www.mdpi.com/2075-1702/12/11/799">doi: 10.3390/machines12110799</a> Authors: Kai Lu Cheng Yin Jing Qian Zhiyan Sun Liqiang Wang In this study, a centrifugal feeding disc device is proposed. To investigate the influence of the process parameters on the discharging efficiency and the lifting of the discharging efficiency, the centrifugal feeding disc device was dynamically simulated based on the discrete element method (DEM), and the simulation results were experimentally verified. Based on the quadratic regression orthogonal test method, a significant lossless regression model of process parameters and discharging efficiency was established, and the response surface of the interaction of process parameters was obtained. The results indicated that the order of influence of the process parameters on the discharging speed of the centrifugal feeding disc was as follows: outer turntable speed &amp;gt; inner turntable speed &amp;gt; inner turntable tilt angle &amp;gt; conical turntable angle. The interaction of the conical turntable angle and the inner turntable tilt angle had the greatest influence on the centrifugal feed disc discharge efficiency. The response surface method (RSM) was used to optimize the process parameters, and the optimal combination of process parameters included an outer turntable speed of 135 r/min, an inner turntable speed of 64 r/min, an inner turntable tilt angle of 7&amp;deg;, and a conical angle of 15&amp;deg;. The discharged efficiency of the optimized centrifugal feeding disc device was increased by 31.9%. ]]></content:encoded> <dc:title>Parameter Optimization Method for Centrifugal Feed Disc Discharging Based on Numerical Simulation and Response Surface</dc:title> <dc:creator>Kai Lu</dc:creator> <dc:creator>Cheng Yin</dc:creator> <dc:creator>Jing Qian</dc:creator> <dc:creator>Zhiyan Sun</dc:creator> <dc:creator>Liqiang Wang</dc:creator> <dc:identifier>doi: 10.3390/machines12110799</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-11</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-11</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>799</prism:startingPage> <prism:doi>10.3390/machines12110799</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/799</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/797"> <title>Machines, Vol. 12, Pages 797: Proposed Multi-ST Model for Collaborating Multiple Robots in Dynamic Environments</title> <link>https://www.mdpi.com/2075-1702/12/11/797</link> <description>Coverage path planning describes the process of finding an effective path robots can take to traverse a defined dynamic operating environment where there are static (fixed) and dynamic (mobile) obstacles that must be located and avoided in coverage path planning. However, most coverage path planning methods are limited in their ability to effectively manage the coordination of multiple robots operating in concert. In this paper, we propose a novel coverage path planning model (termed Multi-ST) which utilizes the spiral-spanning tree coverage algorithm with intelligent reasoning and knowledge-based methods to achieve optimal coverage, obstacle avoidance, and robot coordination. In experimental testing, we have evaluated the proposed model with a comparative analysis of alternative current approaches under the same conditions. The reported results show that the proposed model enables the avoidance of static and moving obstacles by multiple robots operating in concert in a dynamic operating environment. Moreover, the results demonstrate that the proposed model outperforms existing coverage path planning methods in terms of coverage quality, robustness, scalability, and efficiency. In this paper, the assumptions, limitations, and constraints applicable to this study are set out along with related challenges, open research questions, and proposed directions for future research. We posit that our proposed approach can provide an effective basis upon which multiple robots can operate in concert in a range of &amp;lsquo;real-world&amp;rsquo; domains and systems where coverage path planning and the avoidance of static and dynamic obstacles encountered in completing tasks is a systemic requirement.</description> <pubDate>2024-11-11</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 797: Proposed Multi-ST Model for Collaborating Multiple Robots in Dynamic Environments Machines <a href="https://www.mdpi.com/2075-1702/12/11/797">doi: 10.3390/machines12110797</a> Authors: Hai Van Pham Huy Quoc Do Minh Nguyen Quang Farzin Asadi Philip Moore Coverage path planning describes the process of finding an effective path robots can take to traverse a defined dynamic operating environment where there are static (fixed) and dynamic (mobile) obstacles that must be located and avoided in coverage path planning. However, most coverage path planning methods are limited in their ability to effectively manage the coordination of multiple robots operating in concert. In this paper, we propose a novel coverage path planning model (termed Multi-ST) which utilizes the spiral-spanning tree coverage algorithm with intelligent reasoning and knowledge-based methods to achieve optimal coverage, obstacle avoidance, and robot coordination. In experimental testing, we have evaluated the proposed model with a comparative analysis of alternative current approaches under the same conditions. The reported results show that the proposed model enables the avoidance of static and moving obstacles by multiple robots operating in concert in a dynamic operating environment. Moreover, the results demonstrate that the proposed model outperforms existing coverage path planning methods in terms of coverage quality, robustness, scalability, and efficiency. In this paper, the assumptions, limitations, and constraints applicable to this study are set out along with related challenges, open research questions, and proposed directions for future research. We posit that our proposed approach can provide an effective basis upon which multiple robots can operate in concert in a range of &amp;lsquo;real-world&amp;rsquo; domains and systems where coverage path planning and the avoidance of static and dynamic obstacles encountered in completing tasks is a systemic requirement. ]]></content:encoded> <dc:title>Proposed Multi-ST Model for Collaborating Multiple Robots in Dynamic Environments</dc:title> <dc:creator>Hai Van Pham</dc:creator> <dc:creator>Huy Quoc Do</dc:creator> <dc:creator>Minh Nguyen Quang</dc:creator> <dc:creator>Farzin Asadi</dc:creator> <dc:creator>Philip Moore</dc:creator> <dc:identifier>doi: 10.3390/machines12110797</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-11</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-11</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>797</prism:startingPage> <prism:doi>10.3390/machines12110797</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/797</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/796"> <title>Machines, Vol. 12, Pages 796: UNC Charlotte Autonomous Shuttle Pilot Study: An Assessment of Operational Performance, Reliability, and Challenges</title> <link>https://www.mdpi.com/2075-1702/12/11/796</link> <description>This paper presents the findings from an autonomous shuttle pilot program conducted at the University of North Carolina at Charlotte between June and December 2023 as part of the North Carolina Department of Transportation&amp;rsquo;s Connected Autonomous Shuttle Supporting Innovation (CASSI) initiative. The shuttle completed 825 trips, transporting 565 passengers along a 2.2-mile mixed-traffic campus route. The study evaluates the shuttle&amp;rsquo;s operational performance, reliability, and challenges using data from onboard sensors, system logs, and operator reports. Key analyses are divided into four areas: service reliability, which assesses autonomy disengagements caused by signal loss, technical issues, and environmental factors; service robustness, focusing on the shuttle&amp;rsquo;s ability to maintain operations under adverse conditions; performance metrics, including average speed, autonomy percentage, and battery usage; and service usage, which examines the number of trips and passengers to gauge efficiency. Signal loss and battery-related issues were the primary causes of service interruptions, while environmental factors like weather and vegetation also affected shuttle performance. Recommendations include enhancing vehicle-to-infrastructure communication and optimizing battery management.</description> <pubDate>2024-11-11</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 796: UNC Charlotte Autonomous Shuttle Pilot Study: An Assessment of Operational Performance, Reliability, and Challenges Machines <a href="https://www.mdpi.com/2075-1702/12/11/796">doi: 10.3390/machines12110796</a> Authors: Mohammadnavid Golchin Abhinav Grandhi Ninad Gore Srinivas S. Pulugurtha Amirhossein Ghasemi This paper presents the findings from an autonomous shuttle pilot program conducted at the University of North Carolina at Charlotte between June and December 2023 as part of the North Carolina Department of Transportation&amp;rsquo;s Connected Autonomous Shuttle Supporting Innovation (CASSI) initiative. The shuttle completed 825 trips, transporting 565 passengers along a 2.2-mile mixed-traffic campus route. The study evaluates the shuttle&amp;rsquo;s operational performance, reliability, and challenges using data from onboard sensors, system logs, and operator reports. Key analyses are divided into four areas: service reliability, which assesses autonomy disengagements caused by signal loss, technical issues, and environmental factors; service robustness, focusing on the shuttle&amp;rsquo;s ability to maintain operations under adverse conditions; performance metrics, including average speed, autonomy percentage, and battery usage; and service usage, which examines the number of trips and passengers to gauge efficiency. Signal loss and battery-related issues were the primary causes of service interruptions, while environmental factors like weather and vegetation also affected shuttle performance. Recommendations include enhancing vehicle-to-infrastructure communication and optimizing battery management. ]]></content:encoded> <dc:title>UNC Charlotte Autonomous Shuttle Pilot Study: An Assessment of Operational Performance, Reliability, and Challenges</dc:title> <dc:creator>Mohammadnavid Golchin</dc:creator> <dc:creator>Abhinav Grandhi</dc:creator> <dc:creator>Ninad Gore</dc:creator> <dc:creator>Srinivas S. Pulugurtha</dc:creator> <dc:creator>Amirhossein Ghasemi</dc:creator> <dc:identifier>doi: 10.3390/machines12110796</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-11</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-11</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>796</prism:startingPage> <prism:doi>10.3390/machines12110796</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/796</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/795"> <title>Machines, Vol. 12, Pages 795: Optimal Inspection and Maintenance Policy: Integrating a Continuous-Time Markov Chain into a Homing Problem</title> <link>https://www.mdpi.com/2075-1702/12/11/795</link> <description>The state of a machine is modeled as a controlled continuous-time Markov chain. Moreover, the machine is being serviced at random times. The aim is to maximize the time until the machine must be repaired, while taking the maintenance costs into account. The dynamic programming equation satisfied by the value function is derived, enabling optimal decision-making regarding inspection rates, and special problems are solved explicitly. This approach minimizes direct maintenance costs along with potential failure expenses, establishing a robust methodology for determining inspection frequencies in reliability-centered maintenance. The results contribute to the advancement of maintenance strategies and provide explicit solutions for particular cases, offering ideas for application in reliability engineering.</description> <pubDate>2024-11-10</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 795: Optimal Inspection and Maintenance Policy: Integrating a Continuous-Time Markov Chain into a Homing Problem Machines <a href="https://www.mdpi.com/2075-1702/12/11/795">doi: 10.3390/machines12110795</a> Authors: Mario Lefebvre Roozbeh Yaghoubi The state of a machine is modeled as a controlled continuous-time Markov chain. Moreover, the machine is being serviced at random times. The aim is to maximize the time until the machine must be repaired, while taking the maintenance costs into account. The dynamic programming equation satisfied by the value function is derived, enabling optimal decision-making regarding inspection rates, and special problems are solved explicitly. This approach minimizes direct maintenance costs along with potential failure expenses, establishing a robust methodology for determining inspection frequencies in reliability-centered maintenance. The results contribute to the advancement of maintenance strategies and provide explicit solutions for particular cases, offering ideas for application in reliability engineering. ]]></content:encoded> <dc:title>Optimal Inspection and Maintenance Policy: Integrating a Continuous-Time Markov Chain into a Homing Problem</dc:title> <dc:creator>Mario Lefebvre</dc:creator> <dc:creator>Roozbeh Yaghoubi</dc:creator> <dc:identifier>doi: 10.3390/machines12110795</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-10</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-10</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>795</prism:startingPage> <prism:doi>10.3390/machines12110795</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/795</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/794"> <title>Machines, Vol. 12, Pages 794: Design of a Thermal Performance Test Equipment for a High-Temperature and High-Pressure Heat Exchanger in an Aero-Engine</title> <link>https://www.mdpi.com/2075-1702/12/11/794</link> <description>For next-generation power systems, particularly aero-gas turbine engines, ultra-light and highly efficient heat exchangers are considered key enabling technologies for realizing advanced cycles. Consequently, the development of efficient and accurate aero-engine heat exchanger test equipment is essential to support future gas turbine heat exchanger advancements. This paper presents the development of a high-pressure and high-temperature (HPHT) heat exchanger test facility designed for aero-engine heat exchangers. The maximum temperature and pressure of the test facility were configured to simulate the conditions of the last-stage compressor of a large civil engine, specifically 1000 K and 5.5 MPa. These conditions were achieved using multiple electric heater systems in conjunction with an air compression system consisting of three turbo compressor units and a reciprocating compressor unit. A commissioning test was conducted using a compact tubular heat exchanger, and the results indicate that the test facility operates stably and that the measured data closely align with the predicted performance of the heat exchanger. A commissioning test of the tubular heat exchanger showed a thermal imbalance of 1.02% between the high-pressure (HP) and low-pressure (LP) lines. This level of imbalance is consistent with the ISO standard uncertainty of &amp;plusmn;2.3% for heat dissipation. In addition, CFD simulation results indicated an average deviation of approximately 1.4% in the low-pressure outlet temperature. The close alignment between experimental and CFD results confirms the theoretical reliability of the test bench. The HPHT thermal performance test facility will be expected to serve as a critical test bed for evaluating heat exchangers for current and future gas turbine applications.</description> <pubDate>2024-11-10</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 794: Design of a Thermal Performance Test Equipment for a High-Temperature and High-Pressure Heat Exchanger in an Aero-Engine Machines <a href="https://www.mdpi.com/2075-1702/12/11/794">doi: 10.3390/machines12110794</a> Authors: Wongeun Yun Manyeong Ha Kuisoon Kim Geesoo Lee For next-generation power systems, particularly aero-gas turbine engines, ultra-light and highly efficient heat exchangers are considered key enabling technologies for realizing advanced cycles. Consequently, the development of efficient and accurate aero-engine heat exchanger test equipment is essential to support future gas turbine heat exchanger advancements. This paper presents the development of a high-pressure and high-temperature (HPHT) heat exchanger test facility designed for aero-engine heat exchangers. The maximum temperature and pressure of the test facility were configured to simulate the conditions of the last-stage compressor of a large civil engine, specifically 1000 K and 5.5 MPa. These conditions were achieved using multiple electric heater systems in conjunction with an air compression system consisting of three turbo compressor units and a reciprocating compressor unit. A commissioning test was conducted using a compact tubular heat exchanger, and the results indicate that the test facility operates stably and that the measured data closely align with the predicted performance of the heat exchanger. A commissioning test of the tubular heat exchanger showed a thermal imbalance of 1.02% between the high-pressure (HP) and low-pressure (LP) lines. This level of imbalance is consistent with the ISO standard uncertainty of &amp;plusmn;2.3% for heat dissipation. In addition, CFD simulation results indicated an average deviation of approximately 1.4% in the low-pressure outlet temperature. The close alignment between experimental and CFD results confirms the theoretical reliability of the test bench. The HPHT thermal performance test facility will be expected to serve as a critical test bed for evaluating heat exchangers for current and future gas turbine applications. ]]></content:encoded> <dc:title>Design of a Thermal Performance Test Equipment for a High-Temperature and High-Pressure Heat Exchanger in an Aero-Engine</dc:title> <dc:creator>Wongeun Yun</dc:creator> <dc:creator>Manyeong Ha</dc:creator> <dc:creator>Kuisoon Kim</dc:creator> <dc:creator>Geesoo Lee</dc:creator> <dc:identifier>doi: 10.3390/machines12110794</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-10</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-10</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>794</prism:startingPage> <prism:doi>10.3390/machines12110794</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/794</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/793"> <title>Machines, Vol. 12, Pages 793: A Reconfigurable Architecture for Industrial Control Systems: Overview and Challenges</title> <link>https://www.mdpi.com/2075-1702/12/11/793</link> <description>The closed architecture and stand-alone operation model of traditional industrial control systems limit their ability to leverage ubiquitous infrastructure resources for more flexible and intelligent development. This restriction hinders their ability to rapidly, economically, and sustainably respond to mass customization demands. Existing proposals for open and networked architectures have failed to break the vicious cycle of closed architectures and stand-alone operation models because they do not address the core issue: the tight coupling among the control, infrastructure, and actuator domains. This paper proposes a reconfigurable architecture that decouples these domains, structuring the control system across three planes: control, infrastructure, and actuator. The computer numerical control (CNC) system serves as a primary example to illustrate this reconfigurable architecture. After reviewing open and networked architectures and discussing the characteristics of this reconfigurable architecture, this paper identifies three key challenges: deterministic control functionality, the decoupling of control modules from infrastructures, and the management of control modules, infrastructures, and actuators. Each challenge is examined in detail, and potential solutions are proposed based on emerging technologies.</description> <pubDate>2024-11-09</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 793: A Reconfigurable Architecture for Industrial Control Systems: Overview and Challenges Machines <a href="https://www.mdpi.com/2075-1702/12/11/793">doi: 10.3390/machines12110793</a> Authors: Lisi Liu Zijie Xu Xiaobin Qu The closed architecture and stand-alone operation model of traditional industrial control systems limit their ability to leverage ubiquitous infrastructure resources for more flexible and intelligent development. This restriction hinders their ability to rapidly, economically, and sustainably respond to mass customization demands. Existing proposals for open and networked architectures have failed to break the vicious cycle of closed architectures and stand-alone operation models because they do not address the core issue: the tight coupling among the control, infrastructure, and actuator domains. This paper proposes a reconfigurable architecture that decouples these domains, structuring the control system across three planes: control, infrastructure, and actuator. The computer numerical control (CNC) system serves as a primary example to illustrate this reconfigurable architecture. After reviewing open and networked architectures and discussing the characteristics of this reconfigurable architecture, this paper identifies three key challenges: deterministic control functionality, the decoupling of control modules from infrastructures, and the management of control modules, infrastructures, and actuators. Each challenge is examined in detail, and potential solutions are proposed based on emerging technologies. ]]></content:encoded> <dc:title>A Reconfigurable Architecture for Industrial Control Systems: Overview and Challenges</dc:title> <dc:creator>Lisi Liu</dc:creator> <dc:creator>Zijie Xu</dc:creator> <dc:creator>Xiaobin Qu</dc:creator> <dc:identifier>doi: 10.3390/machines12110793</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-09</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-09</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>793</prism:startingPage> <prism:doi>10.3390/machines12110793</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/793</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/792"> <title>Machines, Vol. 12, Pages 792: A Multi-Scale Convolutional Neural Network with Self-Knowledge Distillation for Bearing Fault Diagnosis</title> <link>https://www.mdpi.com/2075-1702/12/11/792</link> <description>Efficient bearing fault diagnosis not only extends the operational lifespan of rolling bearings but also reduces unnecessary maintenance and resource waste. However, current deep learning-based methods face significant challenges, particularly due to the scarcity of fault data, which impedes the models&amp;rsquo; ability to effectively learn parameters. Additionally, many existing methods rely on single-scale features, hindering the capture of global contextual information and diminishing diagnostic accuracy. To address these challenges, this paper proposes a Multi-Scale Convolutional Neural Network with Self-Knowledge Distillation (MSCNN-SKD) for bearing fault diagnosis. The MSCNN-SKD employs a five-stage architecture. Stage 1 uses wide-kernel convolution for initial feature extraction, while Stages 2 through 5 integrate a parallel multi-scale convolutional structure to capture both global contextual information and long-range dependencies. In the final two stages, a self-distillation process enhances learning by allowing deep-layer features to guide shallow-layer learning, improving performance, especially in data-limited scenarios. Extensive experiments on multiple datasets validate the model&amp;rsquo;s high diagnostic accuracy, computational efficiency, and robustness, demonstrating its suitability for real-time industrial applications in resource-limited environments.</description> <pubDate>2024-11-09</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 792: A Multi-Scale Convolutional Neural Network with Self-Knowledge Distillation for Bearing Fault Diagnosis Machines <a href="https://www.mdpi.com/2075-1702/12/11/792">doi: 10.3390/machines12110792</a> Authors: Jiamao Yu Hexuan Hu Efficient bearing fault diagnosis not only extends the operational lifespan of rolling bearings but also reduces unnecessary maintenance and resource waste. However, current deep learning-based methods face significant challenges, particularly due to the scarcity of fault data, which impedes the models&amp;rsquo; ability to effectively learn parameters. Additionally, many existing methods rely on single-scale features, hindering the capture of global contextual information and diminishing diagnostic accuracy. To address these challenges, this paper proposes a Multi-Scale Convolutional Neural Network with Self-Knowledge Distillation (MSCNN-SKD) for bearing fault diagnosis. The MSCNN-SKD employs a five-stage architecture. Stage 1 uses wide-kernel convolution for initial feature extraction, while Stages 2 through 5 integrate a parallel multi-scale convolutional structure to capture both global contextual information and long-range dependencies. In the final two stages, a self-distillation process enhances learning by allowing deep-layer features to guide shallow-layer learning, improving performance, especially in data-limited scenarios. Extensive experiments on multiple datasets validate the model&amp;rsquo;s high diagnostic accuracy, computational efficiency, and robustness, demonstrating its suitability for real-time industrial applications in resource-limited environments. ]]></content:encoded> <dc:title>A Multi-Scale Convolutional Neural Network with Self-Knowledge Distillation for Bearing Fault Diagnosis</dc:title> <dc:creator>Jiamao Yu</dc:creator> <dc:creator>Hexuan Hu</dc:creator> <dc:identifier>doi: 10.3390/machines12110792</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-09</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-09</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>792</prism:startingPage> <prism:doi>10.3390/machines12110792</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/792</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/791"> <title>Machines, Vol. 12, Pages 791: Influence of Distributor Structure on Through-Sea Valve Vibration Characteristics and Improvement Design</title> <link>https://www.mdpi.com/2075-1702/12/11/791</link> <description>To address the issue of excessive transient noise during the opening and closing of a sea valve, a method for reducing pressure fluctuations during the opening of the electromagnetic hydraulic distributor has been proposed by analyzing the structure and working principle of the distributor. Based on theoretical calculation and simulation analysis, the size and shape of the buffer slot of the flow hole are determined under the condition that the stable working flow rate remains unchanged. An improved electromagnetic hydraulic distributor is developed and tested. The results indicate that this method can effectively control the opening and closing transient noise of the sea valve.</description> <pubDate>2024-11-08</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 791: Influence of Distributor Structure on Through-Sea Valve Vibration Characteristics and Improvement Design Machines <a href="https://www.mdpi.com/2075-1702/12/11/791">doi: 10.3390/machines12110791</a> Authors: Qingchao Yang Zebin Li Aimin Diao Zhaozhao Ma To address the issue of excessive transient noise during the opening and closing of a sea valve, a method for reducing pressure fluctuations during the opening of the electromagnetic hydraulic distributor has been proposed by analyzing the structure and working principle of the distributor. Based on theoretical calculation and simulation analysis, the size and shape of the buffer slot of the flow hole are determined under the condition that the stable working flow rate remains unchanged. An improved electromagnetic hydraulic distributor is developed and tested. The results indicate that this method can effectively control the opening and closing transient noise of the sea valve. ]]></content:encoded> <dc:title>Influence of Distributor Structure on Through-Sea Valve Vibration Characteristics and Improvement Design</dc:title> <dc:creator>Qingchao Yang</dc:creator> <dc:creator>Zebin Li</dc:creator> <dc:creator>Aimin Diao</dc:creator> <dc:creator>Zhaozhao Ma</dc:creator> <dc:identifier>doi: 10.3390/machines12110791</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-08</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-08</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>791</prism:startingPage> <prism:doi>10.3390/machines12110791</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/791</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/790"> <title>Machines, Vol. 12, Pages 790: Characterization of Surface Integrity of 3D-Printed Stainless Steel by Successive Grinding and Varied Burnishing Parameters</title> <link>https://www.mdpi.com/2075-1702/12/11/790</link> <description>Additive manufacturing (AM)&amp;rsquo;s ability to produce customized products with reduced material wastage and other advantages helped the technology to gain popularity in many industries. However, its poor surface integrity is its weak side, and to overcome this, additional post-processes are essential. Slide diamond burnishing, known for its enhancement of surface roughness, residual stress, microhardness, and other properties, was combined with grinding in this research after 3D printing of MetcoAdd 17-4PH-A to mitigate the mentioned shortcomings. This study aimed to analyze the effects of each process on surface roughness, residual stress (both on the surface and in-depth), and microhardness. Workpieces were ground with the same parameters and burnished with four levels of force, feed, and number of passes. The L16 Taguchi experimental design was used to optimize the process parameters and to study their effects. For surface roughness, the optimum parameters were found to be 60 N force, 0.02 m/min feed rate, and three passes. The longitudinal surface residual stress has optimal values at 80 N force, 0.02 m/min feed rate, and four passes. In the case of transverse surface residual stress, the optimal values were 60 N force, 0.17 m/min feed rate, and three passes. Microhardness was maximized with 60 N force, 0.02 m/min feed rate, and one pass. Additionally, the in-depth residual stress for selected surfaces was investigated, and 100 N force showed a deep burnishing effect. Further multi-objective optimization using desirability function analysis found that the optimal parameters for all responses were achieved at the fourth burnishing force level (100 N), the first tool feed level (0.02 m/min), and the fourth number of passes level (four passes). Ultimately, both grinding and burnishing processes exhibited significant enhancements in the measured parameters.</description> <pubDate>2024-11-07</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 790: Characterization of Surface Integrity of 3D-Printed Stainless Steel by Successive Grinding and Varied Burnishing Parameters Machines <a href="https://www.mdpi.com/2075-1702/12/11/790">doi: 10.3390/machines12110790</a> Authors: Frezgi Tesfom Kebede Jawad Zaghal Csaba Felho Additive manufacturing (AM)&amp;rsquo;s ability to produce customized products with reduced material wastage and other advantages helped the technology to gain popularity in many industries. However, its poor surface integrity is its weak side, and to overcome this, additional post-processes are essential. Slide diamond burnishing, known for its enhancement of surface roughness, residual stress, microhardness, and other properties, was combined with grinding in this research after 3D printing of MetcoAdd 17-4PH-A to mitigate the mentioned shortcomings. This study aimed to analyze the effects of each process on surface roughness, residual stress (both on the surface and in-depth), and microhardness. Workpieces were ground with the same parameters and burnished with four levels of force, feed, and number of passes. The L16 Taguchi experimental design was used to optimize the process parameters and to study their effects. For surface roughness, the optimum parameters were found to be 60 N force, 0.02 m/min feed rate, and three passes. The longitudinal surface residual stress has optimal values at 80 N force, 0.02 m/min feed rate, and four passes. In the case of transverse surface residual stress, the optimal values were 60 N force, 0.17 m/min feed rate, and three passes. Microhardness was maximized with 60 N force, 0.02 m/min feed rate, and one pass. Additionally, the in-depth residual stress for selected surfaces was investigated, and 100 N force showed a deep burnishing effect. Further multi-objective optimization using desirability function analysis found that the optimal parameters for all responses were achieved at the fourth burnishing force level (100 N), the first tool feed level (0.02 m/min), and the fourth number of passes level (four passes). Ultimately, both grinding and burnishing processes exhibited significant enhancements in the measured parameters. ]]></content:encoded> <dc:title>Characterization of Surface Integrity of 3D-Printed Stainless Steel by Successive Grinding and Varied Burnishing Parameters</dc:title> <dc:creator>Frezgi Tesfom Kebede</dc:creator> <dc:creator>Jawad Zaghal</dc:creator> <dc:creator>Csaba Felho</dc:creator> <dc:identifier>doi: 10.3390/machines12110790</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-07</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-07</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>790</prism:startingPage> <prism:doi>10.3390/machines12110790</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/790</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/789"> <title>Machines, Vol. 12, Pages 789: Wear and Damage Study of Straw Chopper Knives in Combine Harvesters</title> <link>https://www.mdpi.com/2075-1702/12/11/789</link> <description>Most of the biomass of cereal straw is chopped and left on the field as organic fertilizer, but its conversion into fertilizer depends on the quality of chopping, which is influenced by the wear of the chopping blades. The aim of the study was to determine the influence of the contamination of the cereal straw on the wear of the combine chopper blades. The study was conducted during the harvest in 2022, when 30 &amp;plusmn; 1% of the grain was lodged and contaminated with abrasive soil particles (poor conditions), and in 2023, when the straw was unlodged and clean (excellent conditions). Six sets of blades with different mechanical and geometric properties were selected. The results showed that the wear ranges were very different: 1.47&amp;ndash;2.99 g/100 ha in 2022 and 0.72&amp;ndash;2.14 g/100 ha in 2023. For micro-abrasive wear, the hardness of the blades (349&amp;ndash;568 HV) and the cutting edge angle (20&amp;deg;&amp;ndash;29&amp;deg;) were important factors of their wear resistance. When the clean straw was chopped, the influence of the blade hardness and cutting edge angle on wear was not significant, and the wear was less. The wear of the blades had a sinusoidal character, which was related to the position of the blades on the chopping drum. This character depends on the design of the chopper and not on the straw quality.</description> <pubDate>2024-11-07</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 789: Wear and Damage Study of Straw Chopper Knives in Combine Harvesters Machines <a href="https://www.mdpi.com/2075-1702/12/11/789">doi: 10.3390/machines12110789</a> Authors: Vytenis Jankauskas Robertas Abrutis Audrius 沤unda Most of the biomass of cereal straw is chopped and left on the field as organic fertilizer, but its conversion into fertilizer depends on the quality of chopping, which is influenced by the wear of the chopping blades. The aim of the study was to determine the influence of the contamination of the cereal straw on the wear of the combine chopper blades. The study was conducted during the harvest in 2022, when 30 &amp;plusmn; 1% of the grain was lodged and contaminated with abrasive soil particles (poor conditions), and in 2023, when the straw was unlodged and clean (excellent conditions). Six sets of blades with different mechanical and geometric properties were selected. The results showed that the wear ranges were very different: 1.47&amp;ndash;2.99 g/100 ha in 2022 and 0.72&amp;ndash;2.14 g/100 ha in 2023. For micro-abrasive wear, the hardness of the blades (349&amp;ndash;568 HV) and the cutting edge angle (20&amp;deg;&amp;ndash;29&amp;deg;) were important factors of their wear resistance. When the clean straw was chopped, the influence of the blade hardness and cutting edge angle on wear was not significant, and the wear was less. The wear of the blades had a sinusoidal character, which was related to the position of the blades on the chopping drum. This character depends on the design of the chopper and not on the straw quality. ]]></content:encoded> <dc:title>Wear and Damage Study of Straw Chopper Knives in Combine Harvesters</dc:title> <dc:creator>Vytenis Jankauskas</dc:creator> <dc:creator>Robertas Abrutis</dc:creator> <dc:creator>Audrius 沤unda</dc:creator> <dc:identifier>doi: 10.3390/machines12110789</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-07</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-07</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>789</prism:startingPage> <prism:doi>10.3390/machines12110789</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/789</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/788"> <title>Machines, Vol. 12, Pages 788: Dynamic Characteristics, Analysis, and Measurement of a Large Optical Mirror Processing System</title> <link>https://www.mdpi.com/2075-1702/12/11/788</link> <description>Optical mirrors have high requirements for surface precision, requiring ultra-precision processing. The revolving movement of a computer-controlled optical surfacing (CCOS) grinding system will induce vibrations in a five-degrees-of-freedom hybrid processing robot (5-DOF-HPR) and a flexible support system (FSS) in a large optical mirror processing system (LOMPS). As a result, the mirror surface will vibrate, which will ultimately affect the surface accuracy of the final optical mirror. Therefore, the differential equation representing the vibration of the 5-DOF-HPR is established based on the spatial beam unit, which transforms the generalized coordinates into modal coordinates, thereby removing the coupling terms of the vibration differential under generalized coordinates. At the same time, a dynamic analysis of the CCOS grinding system is performed, and the magnitude and direction of the centrifugal force and reaction force are calculated. Then, the natural frequencies of the 5-DOF-HPR and the FSS are measured experimentally and compared with the simulation results; thus, the accuracy and effectiveness of the model are verified. Finally, the vibration characteristics of the processed optical mirrors under different influencing factors are obtained. A theoretical and experimental basis for parameter optimization and path planning of the LOMPS is provided to improve the surface accuracy of the processed optical mirror.</description> <pubDate>2024-11-07</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 788: Dynamic Characteristics, Analysis, and Measurement of a Large Optical Mirror Processing System Machines <a href="https://www.mdpi.com/2075-1702/12/11/788">doi: 10.3390/machines12110788</a> Authors: Zujin Jin Zixin Yin Hao Liu Fuchao Liu Optical mirrors have high requirements for surface precision, requiring ultra-precision processing. The revolving movement of a computer-controlled optical surfacing (CCOS) grinding system will induce vibrations in a five-degrees-of-freedom hybrid processing robot (5-DOF-HPR) and a flexible support system (FSS) in a large optical mirror processing system (LOMPS). As a result, the mirror surface will vibrate, which will ultimately affect the surface accuracy of the final optical mirror. Therefore, the differential equation representing the vibration of the 5-DOF-HPR is established based on the spatial beam unit, which transforms the generalized coordinates into modal coordinates, thereby removing the coupling terms of the vibration differential under generalized coordinates. At the same time, a dynamic analysis of the CCOS grinding system is performed, and the magnitude and direction of the centrifugal force and reaction force are calculated. Then, the natural frequencies of the 5-DOF-HPR and the FSS are measured experimentally and compared with the simulation results; thus, the accuracy and effectiveness of the model are verified. Finally, the vibration characteristics of the processed optical mirrors under different influencing factors are obtained. A theoretical and experimental basis for parameter optimization and path planning of the LOMPS is provided to improve the surface accuracy of the processed optical mirror. ]]></content:encoded> <dc:title>Dynamic Characteristics, Analysis, and Measurement of a Large Optical Mirror Processing System</dc:title> <dc:creator>Zujin Jin</dc:creator> <dc:creator>Zixin Yin</dc:creator> <dc:creator>Hao Liu</dc:creator> <dc:creator>Fuchao Liu</dc:creator> <dc:identifier>doi: 10.3390/machines12110788</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-07</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-07</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>788</prism:startingPage> <prism:doi>10.3390/machines12110788</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/788</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/787"> <title>Machines, Vol. 12, Pages 787: Fault Diagnosis for Rolling Bearings Under Complex Working Conditions Based on Domain-Conditioned Adaptation</title> <link>https://www.mdpi.com/2075-1702/12/11/787</link> <description>To address the issue of low diagnostic accuracy caused by noise interference and varying rotational speeds in rolling bearings, a fault diagnosis method based on domain-conditioned feature correction is proposed for rolling bearings under complex working conditions. The approach first constructs a multi-scale self-calibrating convolutional neural network to aggregate input signals across different scales, adaptively establishing long-range spatial and inter-channel dependencies at each spatial location, thereby enhancing feature modeling under noisy conditions. Subsequently, a domain-conditioned adaptation strategy is introduced to dynamically adjust the activation of self-calibrating convolution channels in response to the differences between source and target domain inputs, generating correction terms for target domain features to facilitate effective domain-specific knowledge extraction. The method then aligns source and target domain features by minimizing inter-domain feature distribution discrepancies, explicitly mitigating the distribution variations induced by changes in working conditions. Finally, within a structural risk minimization framework, model parameters are iteratively optimized to achieve minimal distribution discrepancy, resulting in an optimal coefficient matrix for fault diagnosis. Experimental results using variable working condition datasets demonstrate that the proposed method consistently achieves diagnostic accuracies exceeding 95%, substantiating its feasibility and effectiveness.</description> <pubDate>2024-11-07</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 787: Fault Diagnosis for Rolling Bearings Under Complex Working Conditions Based on Domain-Conditioned Adaptation Machines <a href="https://www.mdpi.com/2075-1702/12/11/787">doi: 10.3390/machines12110787</a> Authors: Xu Zhang Gaoquan Gu To address the issue of low diagnostic accuracy caused by noise interference and varying rotational speeds in rolling bearings, a fault diagnosis method based on domain-conditioned feature correction is proposed for rolling bearings under complex working conditions. The approach first constructs a multi-scale self-calibrating convolutional neural network to aggregate input signals across different scales, adaptively establishing long-range spatial and inter-channel dependencies at each spatial location, thereby enhancing feature modeling under noisy conditions. Subsequently, a domain-conditioned adaptation strategy is introduced to dynamically adjust the activation of self-calibrating convolution channels in response to the differences between source and target domain inputs, generating correction terms for target domain features to facilitate effective domain-specific knowledge extraction. The method then aligns source and target domain features by minimizing inter-domain feature distribution discrepancies, explicitly mitigating the distribution variations induced by changes in working conditions. Finally, within a structural risk minimization framework, model parameters are iteratively optimized to achieve minimal distribution discrepancy, resulting in an optimal coefficient matrix for fault diagnosis. Experimental results using variable working condition datasets demonstrate that the proposed method consistently achieves diagnostic accuracies exceeding 95%, substantiating its feasibility and effectiveness. ]]></content:encoded> <dc:title>Fault Diagnosis for Rolling Bearings Under Complex Working Conditions Based on Domain-Conditioned Adaptation</dc:title> <dc:creator>Xu Zhang</dc:creator> <dc:creator>Gaoquan Gu</dc:creator> <dc:identifier>doi: 10.3390/machines12110787</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-07</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-07</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>787</prism:startingPage> <prism:doi>10.3390/machines12110787</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/787</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/786"> <title>Machines, Vol. 12, Pages 786: Robotic Grasping Technology Integrating Large Kernel Convolution and Residual Connections</title> <link>https://www.mdpi.com/2075-1702/12/11/786</link> <description>To meet real-time grasping demands in complex environments, this paper proposes a lightweight yet high-performance robotic grasping model. The model integrates large kernel convolution and residual connections to generate grasping information for unknown objects from RGB and depth images, enabling real-time generation of stable grasping plans from the images. The proposed model achieved favorable accuracy on both the Cornell and Jacquard standard grasping datasets. Compared to other methods, the proposed model significantly reduces the number of parameters while achieving comparable performance, making it a lightweight model. Additionally, real-world experiments were conducted using a six-axis collaborative robot on a set of previously unseen household objects with diverse and adversarial shapes, achieving a comprehensive grasping success rate of 93.7%. Experimental results demonstrate that the proposed model not only improves grasping accuracy but also has strong potential for practical applications, particularly in resource-constrained robotic systems.</description> <pubDate>2024-11-07</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 786: Robotic Grasping Technology Integrating Large Kernel Convolution and Residual Connections Machines <a href="https://www.mdpi.com/2075-1702/12/11/786">doi: 10.3390/machines12110786</a> Authors: Liang Li Nan Li Rui Nan Yangfei He Chunlei Li Weiliang Zhang Pan Fan To meet real-time grasping demands in complex environments, this paper proposes a lightweight yet high-performance robotic grasping model. The model integrates large kernel convolution and residual connections to generate grasping information for unknown objects from RGB and depth images, enabling real-time generation of stable grasping plans from the images. The proposed model achieved favorable accuracy on both the Cornell and Jacquard standard grasping datasets. Compared to other methods, the proposed model significantly reduces the number of parameters while achieving comparable performance, making it a lightweight model. Additionally, real-world experiments were conducted using a six-axis collaborative robot on a set of previously unseen household objects with diverse and adversarial shapes, achieving a comprehensive grasping success rate of 93.7%. Experimental results demonstrate that the proposed model not only improves grasping accuracy but also has strong potential for practical applications, particularly in resource-constrained robotic systems. ]]></content:encoded> <dc:title>Robotic Grasping Technology Integrating Large Kernel Convolution and Residual Connections</dc:title> <dc:creator>Liang Li</dc:creator> <dc:creator>Nan Li</dc:creator> <dc:creator>Rui Nan</dc:creator> <dc:creator>Yangfei He</dc:creator> <dc:creator>Chunlei Li</dc:creator> <dc:creator>Weiliang Zhang</dc:creator> <dc:creator>Pan Fan</dc:creator> <dc:identifier>doi: 10.3390/machines12110786</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-07</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-07</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>786</prism:startingPage> <prism:doi>10.3390/machines12110786</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/786</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/785"> <title>Machines, Vol. 12, Pages 785: Digital Twin for Flexible Manufacturing Systems and Optimization Through Simulation: A Case Study</title> <link>https://www.mdpi.com/2075-1702/12/11/785</link> <description>The research presented in this paper aligns with the advancement of Industry 4.0 by integrating intelligent machine tools and industrial robots within Flexible Manufacturing Systems (FMS). Primarily, a development approach for Digital Twin (DT) is presented, beginning from the design, sizing, and configuration stages of the system and extending through its implementation, commissioning, operation, and simulation-based optimization. The digitization of current industrial processes entails the development of applications based on modern technologies, utilizing state-of-the-art tools and software. The general objective was to create a digital replica of a process to propose optimization solutions through simulation and subsequently achieve virtual commissioning. The practical nature of the research is reflected in the design and implementation of a Digital Twin for a real physical system processing a family of cylindrical parts within an existing experimental FMS. A digital model of the system was created by defining each individual device and piece of equipment from the physical system, so the virtual model operates just like the real one. By implementing the Digital Twin, both time-based and event-based simulations were performed. Through the execution of multiple scenarios, it was possible to identify system errors and collisions, and propose optimization solutions by implementing complex, collaborative-robot equipment where multiple interactions occur simultaneously.</description> <pubDate>2024-11-07</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 785: Digital Twin for Flexible Manufacturing Systems and Optimization Through Simulation: A Case Study Machines <a href="https://www.mdpi.com/2075-1702/12/11/785">doi: 10.3390/machines12110785</a> Authors: Adriana Florescu The research presented in this paper aligns with the advancement of Industry 4.0 by integrating intelligent machine tools and industrial robots within Flexible Manufacturing Systems (FMS). Primarily, a development approach for Digital Twin (DT) is presented, beginning from the design, sizing, and configuration stages of the system and extending through its implementation, commissioning, operation, and simulation-based optimization. The digitization of current industrial processes entails the development of applications based on modern technologies, utilizing state-of-the-art tools and software. The general objective was to create a digital replica of a process to propose optimization solutions through simulation and subsequently achieve virtual commissioning. The practical nature of the research is reflected in the design and implementation of a Digital Twin for a real physical system processing a family of cylindrical parts within an existing experimental FMS. A digital model of the system was created by defining each individual device and piece of equipment from the physical system, so the virtual model operates just like the real one. By implementing the Digital Twin, both time-based and event-based simulations were performed. Through the execution of multiple scenarios, it was possible to identify system errors and collisions, and propose optimization solutions by implementing complex, collaborative-robot equipment where multiple interactions occur simultaneously. ]]></content:encoded> <dc:title>Digital Twin for Flexible Manufacturing Systems and Optimization Through Simulation: A Case Study</dc:title> <dc:creator>Adriana Florescu</dc:creator> <dc:identifier>doi: 10.3390/machines12110785</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-07</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-07</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>785</prism:startingPage> <prism:doi>10.3390/machines12110785</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/785</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/784"> <title>Machines, Vol. 12, Pages 784: Research on Active&ndash;Passive Training Control Strategies for Upper Limb Rehabilitation Robot</title> <link>https://www.mdpi.com/2075-1702/12/11/784</link> <description>Due to accidents, upper limb movement disorders have become increasingly common. Training can help restore muscle strength and rebuild neurological function. However, the existing single mode has limitations in adapting to the training needs of different rehabilitation stages. Therefore, this paper conducts research on active&amp;ndash;passive training control strategies for an upper limb rehabilitation robot. It establishes an upper limb kinematic model based on the Lagrange method and builds a man&amp;ndash;machine integration dynamics model for upper limb rehabilitation in MATLAB (R2016a)/Simulink. A design active controller, passive controller, and switching controller based on PI and feedforward compensation strategies are proposed to improve training control accuracy. The output moment of the system during active training is planned to ensure the safety and stability of the training process. By utilizing neural networks to train sample data during rehabilitation training, the fuzzy rules and membership functions in fuzzy intention recognition algorithm are optimized to improve the accuracy of intention recognition during training. By adopting the independently developed experimental platform for the upper limb rehabilitation robot, active&amp;ndash;passive training, intention recognition, and training mode switching are achieved. The results show that the active and passive training processes are smooth, the training intention recognition is accurate, and the switching between active and passive training modes is steady. This verifies the feasibility and effectiveness of the established mathematical model in upper limb rehabilitation training.</description> <pubDate>2024-11-06</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 784: Research on Active&ndash;Passive Training Control Strategies for Upper Limb Rehabilitation Robot Machines <a href="https://www.mdpi.com/2075-1702/12/11/784">doi: 10.3390/machines12110784</a> Authors: Yongming Yang Due to accidents, upper limb movement disorders have become increasingly common. Training can help restore muscle strength and rebuild neurological function. However, the existing single mode has limitations in adapting to the training needs of different rehabilitation stages. Therefore, this paper conducts research on active&amp;ndash;passive training control strategies for an upper limb rehabilitation robot. It establishes an upper limb kinematic model based on the Lagrange method and builds a man&amp;ndash;machine integration dynamics model for upper limb rehabilitation in MATLAB (R2016a)/Simulink. A design active controller, passive controller, and switching controller based on PI and feedforward compensation strategies are proposed to improve training control accuracy. The output moment of the system during active training is planned to ensure the safety and stability of the training process. By utilizing neural networks to train sample data during rehabilitation training, the fuzzy rules and membership functions in fuzzy intention recognition algorithm are optimized to improve the accuracy of intention recognition during training. By adopting the independently developed experimental platform for the upper limb rehabilitation robot, active&amp;ndash;passive training, intention recognition, and training mode switching are achieved. The results show that the active and passive training processes are smooth, the training intention recognition is accurate, and the switching between active and passive training modes is steady. This verifies the feasibility and effectiveness of the established mathematical model in upper limb rehabilitation training. ]]></content:encoded> <dc:title>Research on Active&amp;ndash;Passive Training Control Strategies for Upper Limb Rehabilitation Robot</dc:title> <dc:creator>Yongming Yang</dc:creator> <dc:identifier>doi: 10.3390/machines12110784</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-06</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-06</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>784</prism:startingPage> <prism:doi>10.3390/machines12110784</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/784</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/783"> <title>Machines, Vol. 12, Pages 783: Prediction of Delamination Defects in Drilling of Carbon Fiber Reinforced Polymers Using a Regression-Based Approach</title> <link>https://www.mdpi.com/2075-1702/12/11/783</link> <description>Carbon fiber-reinforced polymer (CFRP) structures have been increasingly used in various aerospace sectors due to their outstanding mechanical properties in recent years. However, the poor machinability of CFRP plates, combined with the inhomogeneous behavior of fibers, poses a challenge for manufacturers and researchers to define the critical factors and conditions necessary to ensure the quality of holes in CFRP structures. This study aims to analyze the effect of drilling parameters on CFRP delamination and to predict hole quality using a regression-based approach. The design of the experiment (DOE) was conducted using Taguchi&amp;rsquo;s L9 3-level orthogonal array. The input drilling variables included the feed rate, spindle speed, and three different drill types. A regression-based model using partial least squares (PLS) was developed to predict delamination defects during the drilling of CFRP plates. The PLS model demonstrated high accuracy in predicting delamination defects, with a Mean Squared Error (MSE) of 0.0045, corresponding to an accuracy of approximately 99.6%, enabling the rapid estimation of delamination. The model&amp;rsquo;s predictions were closely aligned with the experimental results, although some deviations were observed due to tool inefficiencies, particularly with end mill cutters. These findings offer valuable insights for researchers and practitioners, enhancing the understanding of delamination in CFRPs and identifying areas for further investigation.</description> <pubDate>2024-11-06</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 783: Prediction of Delamination Defects in Drilling of Carbon Fiber Reinforced Polymers Using a Regression-Based Approach Machines <a href="https://www.mdpi.com/2075-1702/12/11/783">doi: 10.3390/machines12110783</a> Authors: Mohammad Ghasemian Fard Hamid Baseri Aref Azami Abbas Zolfaghari Carbon fiber-reinforced polymer (CFRP) structures have been increasingly used in various aerospace sectors due to their outstanding mechanical properties in recent years. However, the poor machinability of CFRP plates, combined with the inhomogeneous behavior of fibers, poses a challenge for manufacturers and researchers to define the critical factors and conditions necessary to ensure the quality of holes in CFRP structures. This study aims to analyze the effect of drilling parameters on CFRP delamination and to predict hole quality using a regression-based approach. The design of the experiment (DOE) was conducted using Taguchi&amp;rsquo;s L9 3-level orthogonal array. The input drilling variables included the feed rate, spindle speed, and three different drill types. A regression-based model using partial least squares (PLS) was developed to predict delamination defects during the drilling of CFRP plates. The PLS model demonstrated high accuracy in predicting delamination defects, with a Mean Squared Error (MSE) of 0.0045, corresponding to an accuracy of approximately 99.6%, enabling the rapid estimation of delamination. The model&amp;rsquo;s predictions were closely aligned with the experimental results, although some deviations were observed due to tool inefficiencies, particularly with end mill cutters. These findings offer valuable insights for researchers and practitioners, enhancing the understanding of delamination in CFRPs and identifying areas for further investigation. ]]></content:encoded> <dc:title>Prediction of Delamination Defects in Drilling of Carbon Fiber Reinforced Polymers Using a Regression-Based Approach</dc:title> <dc:creator>Mohammad Ghasemian Fard</dc:creator> <dc:creator>Hamid Baseri</dc:creator> <dc:creator>Aref Azami</dc:creator> <dc:creator>Abbas Zolfaghari</dc:creator> <dc:identifier>doi: 10.3390/machines12110783</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-06</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-06</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>783</prism:startingPage> <prism:doi>10.3390/machines12110783</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/783</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/782"> <title>Machines, Vol. 12, Pages 782: Research on Pose Error Modeling and Compensation of Posture Adjustment Mechanism Based on WOA-RBF Neural Network</title> <link>https://www.mdpi.com/2075-1702/12/11/782</link> <description>This paper is aimed to address the issue of decreased accuracy in the ship block docking caused by the structural errors of posture adjustment mechanism. First, inverse kinematic analysis is performed to investigate the sources of static errors in the mechanism. Subsequently, based on the closed-loop vector method, a pose error model for the moving platform is established, which includes eight categories of error terms. The impact of various structural errors on the pose accuracy of the moving platform is then compared and analyzed under both single-limb and multi-limb configurations. Therefore, a compensation method based on the whale optimization algorithm optimized radial basis function neural network is proposed. By transforming pose errors into actuator length errors, it establishes a predictive model between the theoretical pose of the dynamic platform and actuator length errors. After optimizing the network parameters, it yields the actuator length compensation to correct the actual pose of the dynamic platform. Simulation and experimental results validate the effectiveness of this method in enhancing the motion accuracy of the parallel mechanism. The mean pose accuracy of the moving platform is improved by 85.07%, demonstrating a significant compensation effect.</description> <pubDate>2024-11-06</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 782: Research on Pose Error Modeling and Compensation of Posture Adjustment Mechanism Based on WOA-RBF Neural Network Machines <a href="https://www.mdpi.com/2075-1702/12/11/782">doi: 10.3390/machines12110782</a> Authors: Hongyu Shen Honggen Zhou Yiyang Jin Lei Li Bo Deng Jiawei Xu This paper is aimed to address the issue of decreased accuracy in the ship block docking caused by the structural errors of posture adjustment mechanism. First, inverse kinematic analysis is performed to investigate the sources of static errors in the mechanism. Subsequently, based on the closed-loop vector method, a pose error model for the moving platform is established, which includes eight categories of error terms. The impact of various structural errors on the pose accuracy of the moving platform is then compared and analyzed under both single-limb and multi-limb configurations. Therefore, a compensation method based on the whale optimization algorithm optimized radial basis function neural network is proposed. By transforming pose errors into actuator length errors, it establishes a predictive model between the theoretical pose of the dynamic platform and actuator length errors. After optimizing the network parameters, it yields the actuator length compensation to correct the actual pose of the dynamic platform. Simulation and experimental results validate the effectiveness of this method in enhancing the motion accuracy of the parallel mechanism. The mean pose accuracy of the moving platform is improved by 85.07%, demonstrating a significant compensation effect. ]]></content:encoded> <dc:title>Research on Pose Error Modeling and Compensation of Posture Adjustment Mechanism Based on WOA-RBF Neural Network</dc:title> <dc:creator>Hongyu Shen</dc:creator> <dc:creator>Honggen Zhou</dc:creator> <dc:creator>Yiyang Jin</dc:creator> <dc:creator>Lei Li</dc:creator> <dc:creator>Bo Deng</dc:creator> <dc:creator>Jiawei Xu</dc:creator> <dc:identifier>doi: 10.3390/machines12110782</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-06</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-06</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>782</prism:startingPage> <prism:doi>10.3390/machines12110782</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/782</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/781"> <title>Machines, Vol. 12, Pages 781: Enhanced Output Performance of Two-Level Voltage Source Inverters Using Simplified Model Predictive Control with Multi-Virtual-Voltage Vectors</title> <link>https://www.mdpi.com/2075-1702/12/11/781</link> <description>Interest in electric propulsion ships has garnered attention to reduce ship exhaust emissions. This has sparked extensive research on inverters. While two-level voltage source inverters are commonly utilized in small- and medium-sized ships owing to their simple structure and cost-effectiveness, they have limitations, such as high switching losses and reduced output performance. To address these issues, a model predictive control technique based on virtual voltage vectors is proposed in this study. Conventional two-level voltage source inverters are restricted to using only eight voltage vectors, which limits their output performance. By incorporating virtual voltage vectors, similar performance to multilevel converters can be achieved. The proposed technique involves a pre-voltage selection method that enhances output performance without increasing computational load. Through simulation and experiments, improved output current THD and current error were observed under various load conditions. This showcases the potential for enhancing the efficiency and performance of electric propulsion ships.</description> <pubDate>2024-11-06</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 781: Enhanced Output Performance of Two-Level Voltage Source Inverters Using Simplified Model Predictive Control with Multi-Virtual-Voltage Vectors Machines <a href="https://www.mdpi.com/2075-1702/12/11/781">doi: 10.3390/machines12110781</a> Authors: Hyeongyo Chae Chan Roh Interest in electric propulsion ships has garnered attention to reduce ship exhaust emissions. This has sparked extensive research on inverters. While two-level voltage source inverters are commonly utilized in small- and medium-sized ships owing to their simple structure and cost-effectiveness, they have limitations, such as high switching losses and reduced output performance. To address these issues, a model predictive control technique based on virtual voltage vectors is proposed in this study. Conventional two-level voltage source inverters are restricted to using only eight voltage vectors, which limits their output performance. By incorporating virtual voltage vectors, similar performance to multilevel converters can be achieved. The proposed technique involves a pre-voltage selection method that enhances output performance without increasing computational load. Through simulation and experiments, improved output current THD and current error were observed under various load conditions. This showcases the potential for enhancing the efficiency and performance of electric propulsion ships. ]]></content:encoded> <dc:title>Enhanced Output Performance of Two-Level Voltage Source Inverters Using Simplified Model Predictive Control with Multi-Virtual-Voltage Vectors</dc:title> <dc:creator>Hyeongyo Chae</dc:creator> <dc:creator>Chan Roh</dc:creator> <dc:identifier>doi: 10.3390/machines12110781</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-06</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-06</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>781</prism:startingPage> <prism:doi>10.3390/machines12110781</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/781</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/780"> <title>Machines, Vol. 12, Pages 780: Design and Performance of a Planetary Gearbox with Two DOFs</title> <link>https://www.mdpi.com/2075-1702/12/11/780</link> <description>The article aims to describe the design and operation of a fundamentally new self-regulating planetary transmission, which, without a control system, changes the gear ratio under the influence of a variable external load. A self-regulating transmission can be created based on a kinematic chain with two degrees of freedom, having only one input. According to the laws of mechanics, such a chain has no definability of motion, since the number of inputs must be equal to the number of degrees of freedom. The equilibrium of a two-movable chain with one input can obtained by creating an additional constraint that substitutes a reaction in the instantaneous center of the intermediate link velocities by the friction moment in the hinge of the intermediate link. The friction moment creates a force constraint, which is taken into account in the equilibrium condition. The obtained equilibrium conditions ensure the definiteness of motion and the ability of self-regulation in the form of an inversely proportional dependence of the speed of the output link on the variable external load. The described method makes it possible to create a fundamentally new class of self-regulating mechanisms in all branches of technology. The interaction of kinematic and force parameters and the construction of parameter graphs was performed using the SolidWorks 2021 program with certain additions. The experimental studies performed confirm the reliability of the theoretical developments.</description> <pubDate>2024-11-06</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 780: Design and Performance of a Planetary Gearbox with Two DOFs Machines <a href="https://www.mdpi.com/2075-1702/12/11/780">doi: 10.3390/machines12110780</a> Authors: Dana Tulekenova Marco Ceccarelli Konstantin Ivanov Matteo Russo The article aims to describe the design and operation of a fundamentally new self-regulating planetary transmission, which, without a control system, changes the gear ratio under the influence of a variable external load. A self-regulating transmission can be created based on a kinematic chain with two degrees of freedom, having only one input. According to the laws of mechanics, such a chain has no definability of motion, since the number of inputs must be equal to the number of degrees of freedom. The equilibrium of a two-movable chain with one input can obtained by creating an additional constraint that substitutes a reaction in the instantaneous center of the intermediate link velocities by the friction moment in the hinge of the intermediate link. The friction moment creates a force constraint, which is taken into account in the equilibrium condition. The obtained equilibrium conditions ensure the definiteness of motion and the ability of self-regulation in the form of an inversely proportional dependence of the speed of the output link on the variable external load. The described method makes it possible to create a fundamentally new class of self-regulating mechanisms in all branches of technology. The interaction of kinematic and force parameters and the construction of parameter graphs was performed using the SolidWorks 2021 program with certain additions. The experimental studies performed confirm the reliability of the theoretical developments. ]]></content:encoded> <dc:title>Design and Performance of a Planetary Gearbox with Two DOFs</dc:title> <dc:creator>Dana Tulekenova</dc:creator> <dc:creator>Marco Ceccarelli</dc:creator> <dc:creator>Konstantin Ivanov</dc:creator> <dc:creator>Matteo Russo</dc:creator> <dc:identifier>doi: 10.3390/machines12110780</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-06</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-06</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>780</prism:startingPage> <prism:doi>10.3390/machines12110780</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/780</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/779"> <title>Machines, Vol. 12, Pages 779: An Enhanced Spectral Amplitude Modulation Method for Fault Diagnosis of Rolling Bearings</title> <link>https://www.mdpi.com/2075-1702/12/11/779</link> <description>As a classic nonlinear filtering method, Spectral Amplitude Modulation (SAM) is widely used in the field of bearing fault characteristic frequency identification. However, when the vibration signal contains high-intensity noise interference, the accuracy of SAM in identifying fault characteristic frequencies is greatly reduced. To solve the above problems, a Data Enhancement Spectral Amplitude Modulation (DA-SAM) method is proposed. This method further processes the modified signal through improved wavelet transform (IWT), calculates its logarithmic maximum square envelope spectrum to replace the original square envelope spectrum, and finally completes SAM. By highlighting signal characteristics and strengthening feature information, interference information can be minimized, thereby improving the robustness of the SAM method. In this paper, this method is verified through fault data sets. The research results show that this method can effectively reduce the interference of noise on fault diagnosis, and the fault characteristic information obtained is clearer. The superiority of this method compared with the SAM method, Autogram method, and fast spectral kurtosis diagram method is proved.</description> <pubDate>2024-11-06</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 779: An Enhanced Spectral Amplitude Modulation Method for Fault Diagnosis of Rolling Bearings Machines <a href="https://www.mdpi.com/2075-1702/12/11/779">doi: 10.3390/machines12110779</a> Authors: Zongcai Ma Yongqi Chen Tao Zhang Ziyang Liao As a classic nonlinear filtering method, Spectral Amplitude Modulation (SAM) is widely used in the field of bearing fault characteristic frequency identification. However, when the vibration signal contains high-intensity noise interference, the accuracy of SAM in identifying fault characteristic frequencies is greatly reduced. To solve the above problems, a Data Enhancement Spectral Amplitude Modulation (DA-SAM) method is proposed. This method further processes the modified signal through improved wavelet transform (IWT), calculates its logarithmic maximum square envelope spectrum to replace the original square envelope spectrum, and finally completes SAM. By highlighting signal characteristics and strengthening feature information, interference information can be minimized, thereby improving the robustness of the SAM method. In this paper, this method is verified through fault data sets. The research results show that this method can effectively reduce the interference of noise on fault diagnosis, and the fault characteristic information obtained is clearer. The superiority of this method compared with the SAM method, Autogram method, and fast spectral kurtosis diagram method is proved. ]]></content:encoded> <dc:title>An Enhanced Spectral Amplitude Modulation Method for Fault Diagnosis of Rolling Bearings</dc:title> <dc:creator>Zongcai Ma</dc:creator> <dc:creator>Yongqi Chen</dc:creator> <dc:creator>Tao Zhang</dc:creator> <dc:creator>Ziyang Liao</dc:creator> <dc:identifier>doi: 10.3390/machines12110779</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-06</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-06</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>779</prism:startingPage> <prism:doi>10.3390/machines12110779</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/779</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/778"> <title>Machines, Vol. 12, Pages 778: Simulation and Experimental Study on Indentation Rolling Resistance of a Belt Conveyor</title> <link>https://www.mdpi.com/2075-1702/12/11/778</link> <description>In this paper, in order to reduce the indentation rolling resistance of a belt conveyor and improve its operation efficiency, the indentation rolling resistance of a belt conveyor is studied. Firstly, the theoretical calculation of the indentation rolling resistance caused by the contact between a conveyor belt and an idler is studied. Additionally, the expression of the indentation rolling resistance including the multi-element Maxwell relaxation modulus is simplified and deduced using the assumption of small deformation, and the steps of iterative calculation of the indentation rolling resistance through setting the initial values are designed. Then, the multi-component Maxwell relaxation modulus function of the conveyor belt tested in the previous work of the authors is substituted into COMSOL 5.6 finite element software, and the stress distribution caused by the contact between the conveyor belt and the idler under different working conditions is analyzed. Also, a series of measures to reduce the indentation rolling resistance are found through the laws presented by the simulation results. Finally, the experimental study of the indentation rolling resistance is carried out using the indentation rolling resistance testing device from our research group. By comparing the experimental results for the indentation rolling resistance under different working conditions with the theoretical calculation results for the indentation rolling resistance, it was found that the relative error was less than 13%, which proved the feasibility of the indentation rolling resistance and relaxation modulus testing method, as well as the theoretical calculation method for indentation rolling resistance.</description> <pubDate>2024-11-06</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 778: Simulation and Experimental Study on Indentation Rolling Resistance of a Belt Conveyor Machines <a href="https://www.mdpi.com/2075-1702/12/11/778">doi: 10.3390/machines12110778</a> Authors: Lunlun Wan Fuyan Lin In this paper, in order to reduce the indentation rolling resistance of a belt conveyor and improve its operation efficiency, the indentation rolling resistance of a belt conveyor is studied. Firstly, the theoretical calculation of the indentation rolling resistance caused by the contact between a conveyor belt and an idler is studied. Additionally, the expression of the indentation rolling resistance including the multi-element Maxwell relaxation modulus is simplified and deduced using the assumption of small deformation, and the steps of iterative calculation of the indentation rolling resistance through setting the initial values are designed. Then, the multi-component Maxwell relaxation modulus function of the conveyor belt tested in the previous work of the authors is substituted into COMSOL 5.6 finite element software, and the stress distribution caused by the contact between the conveyor belt and the idler under different working conditions is analyzed. Also, a series of measures to reduce the indentation rolling resistance are found through the laws presented by the simulation results. Finally, the experimental study of the indentation rolling resistance is carried out using the indentation rolling resistance testing device from our research group. By comparing the experimental results for the indentation rolling resistance under different working conditions with the theoretical calculation results for the indentation rolling resistance, it was found that the relative error was less than 13%, which proved the feasibility of the indentation rolling resistance and relaxation modulus testing method, as well as the theoretical calculation method for indentation rolling resistance. ]]></content:encoded> <dc:title>Simulation and Experimental Study on Indentation Rolling Resistance of a Belt Conveyor</dc:title> <dc:creator>Lunlun Wan</dc:creator> <dc:creator>Fuyan Lin</dc:creator> <dc:identifier>doi: 10.3390/machines12110778</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-06</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-06</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>778</prism:startingPage> <prism:doi>10.3390/machines12110778</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/778</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/777"> <title>Machines, Vol. 12, Pages 777: Circular Spline Tooth Longitudinal Modification Design and Contact Analysis for Harmonic Drives with Short Flexspline</title> <link>https://www.mdpi.com/2075-1702/12/11/777</link> <description>Harmonic drives (HDs) with short flexspline (FS) always suffer from small meshing areas and severe stress concentration caused by large cone angles when a short FS is assembled and loaded. To address this issue, a tooth longitudinal modification method for the circular spline (CS) with a double circular arc common-tangent tooth profile (DCTP) is proposed. Using neutral layer and envelope conjugation theories, a mathematical model of the conventional straight CS tooth was developed. A shaping cutter for this tooth profile was then designed through coordinate transformation and meshing principles. The proposed longitudinal modification for the CS was achieved by adjusting the cutter&amp;rsquo;s trajectory. A precise finite element model of the HD was developed, revealing that tooth longitudinal modification can reduce the maximum contact pressure by 69.6% and significantly increase the contact area for HDs with short FS. This work provides valuable technical references for improving the contact state of HDs with short FS.</description> <pubDate>2024-11-05</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 777: Circular Spline Tooth Longitudinal Modification Design and Contact Analysis for Harmonic Drives with Short Flexspline Machines <a href="https://www.mdpi.com/2075-1702/12/11/777">doi: 10.3390/machines12110777</a> Authors: Xingyu He Hesheng Feng Menghan Zhang Zaishang Shen Boyang Liu Peng Su Haoyu Liu Yabin Guan Harmonic drives (HDs) with short flexspline (FS) always suffer from small meshing areas and severe stress concentration caused by large cone angles when a short FS is assembled and loaded. To address this issue, a tooth longitudinal modification method for the circular spline (CS) with a double circular arc common-tangent tooth profile (DCTP) is proposed. Using neutral layer and envelope conjugation theories, a mathematical model of the conventional straight CS tooth was developed. A shaping cutter for this tooth profile was then designed through coordinate transformation and meshing principles. The proposed longitudinal modification for the CS was achieved by adjusting the cutter&amp;rsquo;s trajectory. A precise finite element model of the HD was developed, revealing that tooth longitudinal modification can reduce the maximum contact pressure by 69.6% and significantly increase the contact area for HDs with short FS. This work provides valuable technical references for improving the contact state of HDs with short FS. ]]></content:encoded> <dc:title>Circular Spline Tooth Longitudinal Modification Design and Contact Analysis for Harmonic Drives with Short Flexspline</dc:title> <dc:creator>Xingyu He</dc:creator> <dc:creator>Hesheng Feng</dc:creator> <dc:creator>Menghan Zhang</dc:creator> <dc:creator>Zaishang Shen</dc:creator> <dc:creator>Boyang Liu</dc:creator> <dc:creator>Peng Su</dc:creator> <dc:creator>Haoyu Liu</dc:creator> <dc:creator>Yabin Guan</dc:creator> <dc:identifier>doi: 10.3390/machines12110777</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-05</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-05</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>777</prism:startingPage> <prism:doi>10.3390/machines12110777</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/777</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/776"> <title>Machines, Vol. 12, Pages 776: Comprehensive Analysis of Major Fault-to-Failure Mechanisms in Harmonic Drives</title> <link>https://www.mdpi.com/2075-1702/12/11/776</link> <description>The present paper proposes a detailed Failure Mode, Effects, and Criticality Analysis (FMECA) on harmonic drives, focusing on their integration within the UR5 cobot. While harmonic drives are crucial for precision and efficiency in robotic manipulators, they are also prone to several failure modes that may affect the overall reliability of a system. This work provides a comprehensive analysis intended as a benchmark for advancements in predictive maintenance and condition-based monitoring. The results not only offer insights into improving the operational lifespan of harmonic drives, but also provide guidance for engineers working with similar systems across various robotic platforms. Robotic systems have advanced significantly; however, maintaining their reliability is essential, especially in industrial applications where even minor faults can lead to costly downtimes. This article examines the impact of harmonic drive degradation on industrial robots, with a focus on collaborative robotic arms. Condition-Based Maintenance (CBM) and Prognostics and Health Management (PHM) approaches are discussed, highlighting how digital twins and data-driven models can enhance fault detection. A case study using the UR5 collaborative robot illustrates the importance of fault diagnosis in harmonic drives. The analysis of fault-to-failure mechanisms, including wear, pitting, and crack propagation, shows how early detection strategies, such as vibration analysis and proactive maintenance approaches, can improve system reliability. The findings offer insights into failure mode identification, criticality analysis, and recommendations for improving fault tolerance in robotic systems.</description> <pubDate>2024-11-05</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 776: Comprehensive Analysis of Major Fault-to-Failure Mechanisms in Harmonic Drives Machines <a href="https://www.mdpi.com/2075-1702/12/11/776">doi: 10.3390/machines12110776</a> Authors: Roberto Guida Antonio Carlo Bertolino Andrea De Martin Massimo Sorli The present paper proposes a detailed Failure Mode, Effects, and Criticality Analysis (FMECA) on harmonic drives, focusing on their integration within the UR5 cobot. While harmonic drives are crucial for precision and efficiency in robotic manipulators, they are also prone to several failure modes that may affect the overall reliability of a system. This work provides a comprehensive analysis intended as a benchmark for advancements in predictive maintenance and condition-based monitoring. The results not only offer insights into improving the operational lifespan of harmonic drives, but also provide guidance for engineers working with similar systems across various robotic platforms. Robotic systems have advanced significantly; however, maintaining their reliability is essential, especially in industrial applications where even minor faults can lead to costly downtimes. This article examines the impact of harmonic drive degradation on industrial robots, with a focus on collaborative robotic arms. Condition-Based Maintenance (CBM) and Prognostics and Health Management (PHM) approaches are discussed, highlighting how digital twins and data-driven models can enhance fault detection. A case study using the UR5 collaborative robot illustrates the importance of fault diagnosis in harmonic drives. The analysis of fault-to-failure mechanisms, including wear, pitting, and crack propagation, shows how early detection strategies, such as vibration analysis and proactive maintenance approaches, can improve system reliability. The findings offer insights into failure mode identification, criticality analysis, and recommendations for improving fault tolerance in robotic systems. ]]></content:encoded> <dc:title>Comprehensive Analysis of Major Fault-to-Failure Mechanisms in Harmonic Drives</dc:title> <dc:creator>Roberto Guida</dc:creator> <dc:creator>Antonio Carlo Bertolino</dc:creator> <dc:creator>Andrea De Martin</dc:creator> <dc:creator>Massimo Sorli</dc:creator> <dc:identifier>doi: 10.3390/machines12110776</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-05</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-05</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>776</prism:startingPage> <prism:doi>10.3390/machines12110776</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/776</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/775"> <title>Machines, Vol. 12, Pages 775: Piecewise Time Polynomials-Based Control Methods for Obstacle Avoidance and Precision Positioning of Tower Crane Systems with Varying Cable Lengths</title> <link>https://www.mdpi.com/2075-1702/12/11/775</link> <description>During the hoisting and lowering operations of a tower crane, dynamic variations in cable lengths significantly influence the oscillation frequency and amplitude of the load. These variations complicate the oscillation characteristics, heightening the challenge of balancing obstacle avoidance with precise positioning. To tackle this issue, we propose a trajectory planning and tracking control method that integrates hoisting control to reduce the impact of varying cable lengths on load swinging and achieve accurate positioning during obstacle navigation. A novel definition of swing angle is introduced to model the crane&amp;rsquo;s rigid and swinging components separately, enhancing model accuracy while simplifying complexity. A piecewise polynomial constructs the load trajectory in a low-dimensional flat space, which is then mapped to a high-dimensional generalized state space through a homeomorphic transformation, ensuring trajectory smoothness and traceability. A fractional-order sliding mode controller is employed to facilitate rapid and precise tracking of the actuated degrees of freedom, suppressing load oscillation while maintaining positioning accuracy. Experimental validation on a tower crane platform shows that the proposed strategy enables smooth obstacle avoidance and precise target point reaching, even with varying cable lengths.</description> <pubDate>2024-11-04</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 775: Piecewise Time Polynomials-Based Control Methods for Obstacle Avoidance and Precision Positioning of Tower Crane Systems with Varying Cable Lengths Machines <a href="https://www.mdpi.com/2075-1702/12/11/775">doi: 10.3390/machines12110775</a> Authors: Zhiheng Liu Xianghua Ma During the hoisting and lowering operations of a tower crane, dynamic variations in cable lengths significantly influence the oscillation frequency and amplitude of the load. These variations complicate the oscillation characteristics, heightening the challenge of balancing obstacle avoidance with precise positioning. To tackle this issue, we propose a trajectory planning and tracking control method that integrates hoisting control to reduce the impact of varying cable lengths on load swinging and achieve accurate positioning during obstacle navigation. A novel definition of swing angle is introduced to model the crane&amp;rsquo;s rigid and swinging components separately, enhancing model accuracy while simplifying complexity. A piecewise polynomial constructs the load trajectory in a low-dimensional flat space, which is then mapped to a high-dimensional generalized state space through a homeomorphic transformation, ensuring trajectory smoothness and traceability. A fractional-order sliding mode controller is employed to facilitate rapid and precise tracking of the actuated degrees of freedom, suppressing load oscillation while maintaining positioning accuracy. Experimental validation on a tower crane platform shows that the proposed strategy enables smooth obstacle avoidance and precise target point reaching, even with varying cable lengths. ]]></content:encoded> <dc:title>Piecewise Time Polynomials-Based Control Methods for Obstacle Avoidance and Precision Positioning of Tower Crane Systems with Varying Cable Lengths</dc:title> <dc:creator>Zhiheng Liu</dc:creator> <dc:creator>Xianghua Ma</dc:creator> <dc:identifier>doi: 10.3390/machines12110775</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-04</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-04</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>775</prism:startingPage> <prism:doi>10.3390/machines12110775</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/775</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/774"> <title>Machines, Vol. 12, Pages 774: Modal Parameter Identification of Electric Spindles Based on Covariance-Driven Stochastic Subspace</title> <link>https://www.mdpi.com/2075-1702/12/11/774</link> <description>Electric spindles are a critical component of numerically controlled machine tools that directly affect machining precision and efficiency. The accurate identification of the modal parameters of an electric spindle is essential for optimizing design, enhancing dynamic performance, and facilitating fault diagnosis. This study proposes a covariance-driven stochastic subspace identification (SSI-cov) method integrated with a simulated annealing (SA) strategy and fuzzy C-means (FCM) clustering algorithm to achieve the automated identification of modal parameters for electric spindles. Using both finite element simulations and experimental tests conducted at 22 &amp;deg;C, the first five natural frequencies of the electric spindle under free, constrained, and dynamic conditions were extracted. The experimental results demonstrated experiment errors of 0.17% to 0.33%, 1.05% to 3.27%, and 1.29% to 3.31% for the free, constrained, and dynamic states, respectively. Compared to the traditional SSI-cov method, the proposed SA-FCM method improved accuracy by 12.05% to 27.32% in the free state, 17.45% to 47.83% in the constrained state, and 25.45% to 49.12% in the dynamic state. The frequency identification errors were reduced to a range of 2.25 Hz to 20.81 Hz, significantly decreasing errors in higher-order modes and demonstrating the robustness of the algorithm. The proposed method required no manual intervention, and it could be utilized to accurately analyze the modal parameters of electric spindles under free, constrained, and dynamic conditions, providing a precise and reliable solution for the modal analysis of electric spindles in various dynamic states.</description> <pubDate>2024-11-04</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 774: Modal Parameter Identification of Electric Spindles Based on Covariance-Driven Stochastic Subspace Machines <a href="https://www.mdpi.com/2075-1702/12/11/774">doi: 10.3390/machines12110774</a> Authors: Wenhong Zhou Liuzhou Zhong Weimin Kang Yuetong Xu Congcong Luan Jianzhong Fu Electric spindles are a critical component of numerically controlled machine tools that directly affect machining precision and efficiency. The accurate identification of the modal parameters of an electric spindle is essential for optimizing design, enhancing dynamic performance, and facilitating fault diagnosis. This study proposes a covariance-driven stochastic subspace identification (SSI-cov) method integrated with a simulated annealing (SA) strategy and fuzzy C-means (FCM) clustering algorithm to achieve the automated identification of modal parameters for electric spindles. Using both finite element simulations and experimental tests conducted at 22 &amp;deg;C, the first five natural frequencies of the electric spindle under free, constrained, and dynamic conditions were extracted. The experimental results demonstrated experiment errors of 0.17% to 0.33%, 1.05% to 3.27%, and 1.29% to 3.31% for the free, constrained, and dynamic states, respectively. Compared to the traditional SSI-cov method, the proposed SA-FCM method improved accuracy by 12.05% to 27.32% in the free state, 17.45% to 47.83% in the constrained state, and 25.45% to 49.12% in the dynamic state. The frequency identification errors were reduced to a range of 2.25 Hz to 20.81 Hz, significantly decreasing errors in higher-order modes and demonstrating the robustness of the algorithm. The proposed method required no manual intervention, and it could be utilized to accurately analyze the modal parameters of electric spindles under free, constrained, and dynamic conditions, providing a precise and reliable solution for the modal analysis of electric spindles in various dynamic states. ]]></content:encoded> <dc:title>Modal Parameter Identification of Electric Spindles Based on Covariance-Driven Stochastic Subspace</dc:title> <dc:creator>Wenhong Zhou</dc:creator> <dc:creator>Liuzhou Zhong</dc:creator> <dc:creator>Weimin Kang</dc:creator> <dc:creator>Yuetong Xu</dc:creator> <dc:creator>Congcong Luan</dc:creator> <dc:creator>Jianzhong Fu</dc:creator> <dc:identifier>doi: 10.3390/machines12110774</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-04</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-04</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>774</prism:startingPage> <prism:doi>10.3390/machines12110774</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/774</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/773"> <title>Machines, Vol. 12, Pages 773: Model Predictive Control Used in Passenger Vehicles: An Overview</title> <link>https://www.mdpi.com/2075-1702/12/11/773</link> <description>The following article presents a high-level overview of how Model Predictive Control (MPC) is leveraged in passenger vehicles and their subsystems for improved performance. This overview presents the fundamental concepts of MPC algorithms and their common variants. After building some understanding of MPC methods, the paper discusses state-of-the-art examples of how MPC methods are leveraged to perform low- to high-level tasks within a typical passenger vehicle. This review also aims to provide the reader with intuition in formulating MPC systems based on the strengths and weaknesses of the different formulations of MPC. The paper also highlights active areas of research and development.</description> <pubDate>2024-11-04</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 773: Model Predictive Control Used in Passenger Vehicles: An Overview Machines <a href="https://www.mdpi.com/2075-1702/12/11/773">doi: 10.3390/machines12110773</a> Authors: Meaghan Charest-Finn Shabnam Pejhan The following article presents a high-level overview of how Model Predictive Control (MPC) is leveraged in passenger vehicles and their subsystems for improved performance. This overview presents the fundamental concepts of MPC algorithms and their common variants. After building some understanding of MPC methods, the paper discusses state-of-the-art examples of how MPC methods are leveraged to perform low- to high-level tasks within a typical passenger vehicle. This review also aims to provide the reader with intuition in formulating MPC systems based on the strengths and weaknesses of the different formulations of MPC. The paper also highlights active areas of research and development. ]]></content:encoded> <dc:title>Model Predictive Control Used in Passenger Vehicles: An Overview</dc:title> <dc:creator>Meaghan Charest-Finn</dc:creator> <dc:creator>Shabnam Pejhan</dc:creator> <dc:identifier>doi: 10.3390/machines12110773</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-04</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-04</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Review</prism:section> <prism:startingPage>773</prism:startingPage> <prism:doi>10.3390/machines12110773</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/773</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/772"> <title>Machines, Vol. 12, Pages 772: Experimental Investigation and NSGA-III Multi-Criteria Optimization of 60CrMoV18-5 Cold-Work Tool Steel Machinability Under Dry CNC Hard Turning Conditions</title> <link>https://www.mdpi.com/2075-1702/12/11/772</link> <description>This work concerns an experimental investigation dealing with the machinability of 60CrMoV18-5 cold-work tool steel under dry CNC hard turning conditions using a CBN cutting insert. A response surface experiment based on the central composite design was set to conduct dry CNC hard-turning experiments with three different levels for cutting conditions, cutting speed Vc (m/min), feed rate f (mm/rev), and depth of cut &amp;alpha; (mm) while selecting main cutting force and surface roughness Ra as the two machinability responses. The results were analyzed by applying analysis of variance (ANOVA). The effect of cutting conditions on main cutting force and surface roughness was studied through contour plots. Full quadratic regression models were generated to model the relationships between inputs and outputs. Finally, the NSGA-III algorithm was applied to simultaneously optimize the selected machinability parameters by providing beneficial values for determining cutting conditions. The results have shown that surface roughness is mainly affected by feed rate and cutting speed, whereas main cutting force is affected by depth of cut and feed rate.</description> <pubDate>2024-11-03</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 772: Experimental Investigation and NSGA-III Multi-Criteria Optimization of 60CrMoV18-5 Cold-Work Tool Steel Machinability Under Dry CNC Hard Turning Conditions Machines <a href="https://www.mdpi.com/2075-1702/12/11/772">doi: 10.3390/machines12110772</a> Authors: Nikolaos A. Fountas Ioannis G. Papantoniou Dimitrios E. Manolakos Nikolaos M. Vaxevanidis This work concerns an experimental investigation dealing with the machinability of 60CrMoV18-5 cold-work tool steel under dry CNC hard turning conditions using a CBN cutting insert. A response surface experiment based on the central composite design was set to conduct dry CNC hard-turning experiments with three different levels for cutting conditions, cutting speed Vc (m/min), feed rate f (mm/rev), and depth of cut &amp;alpha; (mm) while selecting main cutting force and surface roughness Ra as the two machinability responses. The results were analyzed by applying analysis of variance (ANOVA). The effect of cutting conditions on main cutting force and surface roughness was studied through contour plots. Full quadratic regression models were generated to model the relationships between inputs and outputs. Finally, the NSGA-III algorithm was applied to simultaneously optimize the selected machinability parameters by providing beneficial values for determining cutting conditions. The results have shown that surface roughness is mainly affected by feed rate and cutting speed, whereas main cutting force is affected by depth of cut and feed rate. ]]></content:encoded> <dc:title>Experimental Investigation and NSGA-III Multi-Criteria Optimization of 60CrMoV18-5 Cold-Work Tool Steel Machinability Under Dry CNC Hard Turning Conditions</dc:title> <dc:creator>Nikolaos A. Fountas</dc:creator> <dc:creator>Ioannis G. Papantoniou</dc:creator> <dc:creator>Dimitrios E. Manolakos</dc:creator> <dc:creator>Nikolaos M. Vaxevanidis</dc:creator> <dc:identifier>doi: 10.3390/machines12110772</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-03</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-03</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>772</prism:startingPage> <prism:doi>10.3390/machines12110772</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/772</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/771"> <title>Machines, Vol. 12, Pages 771: Robust Driving Control Design for Precise Positional Motions of Permanent Magnet Synchronous Motor Driven Rotary Machines with Position-Dependent Periodic Disturbances</title> <link>https://www.mdpi.com/2075-1702/12/11/771</link> <description>Position-dependent periodic disturbances often limit the accuracy and smoothness of the positional motion of permanent magnet synchronous motor (PMSM)-driven rotary machines. Because the period of these disturbances varies with the motion velocity of the rotary machine, spatial domain control methods such as spatial iterative learning control (SILC) and spatial repetitive control (SRC) have been proposed and applied to improve rotary machine motion control designs. However, problems with learning period convergence and rotary machine dynamics significantly affect transient motion, further constraining the overall motion performance. To address these challenges, this study developed a robust driving control (RDC) that integrates a robust control design with position-dependent periodic disturbance feedforward compensation, rotary machine dynamics compensation, and proportional&amp;ndash;proportional integral feedback control. A position-dependent periodic disturbance model was developed using multiple position&amp;ndash;sinusoidal signals and identified using a spatial fast Fourier transform. RDC compensates for disturbances and dynamics and considers the effects of model parameter uncertainty and modeling error on the stability of the control system. Several motion control experiments were conducted on a PMSM test bench to compare the RDC, SILC, and SRC. The experimental results demonstrated that although both SILC and SRC can effectively suppress position-dependent periodic disturbances, SILC provides slower position error convergence owing to the learning process, and SILC and SRC result in significant position errors because of the influence of the PMSM-driven rotary machine dynamics. RDC not only suppresses position-dependent periodic disturbances, but also significantly reduces position errors with a reduction rate of 90%. Therefore, the RDC developed in this study effectively suppressed position-dependent periodic disturbances and significantly improved both the transient-state and steady-state position-tracking performances of the PMSM-driven rotary machine.</description> <pubDate>2024-11-01</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 771: Robust Driving Control Design for Precise Positional Motions of Permanent Magnet Synchronous Motor Driven Rotary Machines with Position-Dependent Periodic Disturbances Machines <a href="https://www.mdpi.com/2075-1702/12/11/771">doi: 10.3390/machines12110771</a> Authors: Syh-Shiuh Yeh Zhi-Hong Liu Position-dependent periodic disturbances often limit the accuracy and smoothness of the positional motion of permanent magnet synchronous motor (PMSM)-driven rotary machines. Because the period of these disturbances varies with the motion velocity of the rotary machine, spatial domain control methods such as spatial iterative learning control (SILC) and spatial repetitive control (SRC) have been proposed and applied to improve rotary machine motion control designs. However, problems with learning period convergence and rotary machine dynamics significantly affect transient motion, further constraining the overall motion performance. To address these challenges, this study developed a robust driving control (RDC) that integrates a robust control design with position-dependent periodic disturbance feedforward compensation, rotary machine dynamics compensation, and proportional&amp;ndash;proportional integral feedback control. A position-dependent periodic disturbance model was developed using multiple position&amp;ndash;sinusoidal signals and identified using a spatial fast Fourier transform. RDC compensates for disturbances and dynamics and considers the effects of model parameter uncertainty and modeling error on the stability of the control system. Several motion control experiments were conducted on a PMSM test bench to compare the RDC, SILC, and SRC. The experimental results demonstrated that although both SILC and SRC can effectively suppress position-dependent periodic disturbances, SILC provides slower position error convergence owing to the learning process, and SILC and SRC result in significant position errors because of the influence of the PMSM-driven rotary machine dynamics. RDC not only suppresses position-dependent periodic disturbances, but also significantly reduces position errors with a reduction rate of 90%. Therefore, the RDC developed in this study effectively suppressed position-dependent periodic disturbances and significantly improved both the transient-state and steady-state position-tracking performances of the PMSM-driven rotary machine. ]]></content:encoded> <dc:title>Robust Driving Control Design for Precise Positional Motions of Permanent Magnet Synchronous Motor Driven Rotary Machines with Position-Dependent Periodic Disturbances</dc:title> <dc:creator>Syh-Shiuh Yeh</dc:creator> <dc:creator>Zhi-Hong Liu</dc:creator> <dc:identifier>doi: 10.3390/machines12110771</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-01</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-01</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>771</prism:startingPage> <prism:doi>10.3390/machines12110771</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/771</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/770"> <title>Machines, Vol. 12, Pages 770: Mathematical Modeling and Generating Method of Hourglass Worm Gear Hob&rsquo;s Rake Face Based on a Rotating Paraboloid Surface</title> <link>https://www.mdpi.com/2075-1702/12/11/770</link> <description>The rake angles on both sides of the cutting edges of the hourglass worm gear hob significantly influence its cutting performance, which, in turn, plays a decisive role in the surface quality of the machined worm wheel. To balance the rake angles along the tooth height direction of each hob tooth and enhance the overall cutting performance of the hob, this paper proposes a method that utilizes a rotating paraboloid surface to generate the helical rake face of the hourglass worm gear hob. First, the conjugate condition equations for the rake face generated by the rotating paraboloid surface are derived. A mathematical model for the helical rake face of planar double-enveloping hourglass worm gear hob is established. This study explores the influence of two machining parameters on the rake angle, specifically the milling drive ratio coefficient k and the geometric parameter of a parabolic milling cutter p. Through a systematic analysis of the variations in rake angle at the dividing toroidal surface and along the tooth height direction, the optimal parameter values were identified as k = 0.9115 and p = 0.6834. The results show that, after optimization, the hob rake angle range is around &amp;plusmn;4.7&amp;deg;, with a maximum rake angle difference of 6.3072&amp;deg; along the tooth height direction, and the rake angles on both sides of the teeth are more balanced. The structure of the rake face is more reasonable, reflecting the feasibility of rotating paraboloid tools for forming tools in the machining of complex surfaces.</description> <pubDate>2024-11-01</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 770: Mathematical Modeling and Generating Method of Hourglass Worm Gear Hob&rsquo;s Rake Face Based on a Rotating Paraboloid Surface Machines <a href="https://www.mdpi.com/2075-1702/12/11/770">doi: 10.3390/machines12110770</a> Authors: Yupeng Li Jie Yang Run Gu Zhijiang Chen Chunming Xia The rake angles on both sides of the cutting edges of the hourglass worm gear hob significantly influence its cutting performance, which, in turn, plays a decisive role in the surface quality of the machined worm wheel. To balance the rake angles along the tooth height direction of each hob tooth and enhance the overall cutting performance of the hob, this paper proposes a method that utilizes a rotating paraboloid surface to generate the helical rake face of the hourglass worm gear hob. First, the conjugate condition equations for the rake face generated by the rotating paraboloid surface are derived. A mathematical model for the helical rake face of planar double-enveloping hourglass worm gear hob is established. This study explores the influence of two machining parameters on the rake angle, specifically the milling drive ratio coefficient k and the geometric parameter of a parabolic milling cutter p. Through a systematic analysis of the variations in rake angle at the dividing toroidal surface and along the tooth height direction, the optimal parameter values were identified as k = 0.9115 and p = 0.6834. The results show that, after optimization, the hob rake angle range is around &amp;plusmn;4.7&amp;deg;, with a maximum rake angle difference of 6.3072&amp;deg; along the tooth height direction, and the rake angles on both sides of the teeth are more balanced. The structure of the rake face is more reasonable, reflecting the feasibility of rotating paraboloid tools for forming tools in the machining of complex surfaces. ]]></content:encoded> <dc:title>Mathematical Modeling and Generating Method of Hourglass Worm Gear Hob&amp;rsquo;s Rake Face Based on a Rotating Paraboloid Surface</dc:title> <dc:creator>Yupeng Li</dc:creator> <dc:creator>Jie Yang</dc:creator> <dc:creator>Run Gu</dc:creator> <dc:creator>Zhijiang Chen</dc:creator> <dc:creator>Chunming Xia</dc:creator> <dc:identifier>doi: 10.3390/machines12110770</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-11-01</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-11-01</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>770</prism:startingPage> <prism:doi>10.3390/machines12110770</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/770</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/769"> <title>Machines, Vol. 12, Pages 769: An Improved Adaptive Sliding Mode Control Approach for Anti-Slip Regulation of Electric Vehicles Based on Optimal Slip Ratio</title> <link>https://www.mdpi.com/2075-1702/12/11/769</link> <description>To optimize the acceleration performance of independently driven electric vehicles with four in-wheel motors, this paper proposes an anti-slip regulation (ASR) strategy based on dynamic road surface observer for more efficient tracking of the optimal slip ratio and enhanced vehicle acceleration. The method uses the Unscented Kalman Filter (UKF) observer to estimate vehicle speed and calculate the actual slip ratio, while a fuzzy controller based on the Burckhardt tire model identifies road surfaces. The road&amp;rsquo;s peak adhesion coefficient and optimal slip ratio curve are fitted using a Back Propagation Neural Network (BPNN) optimized by Particle Swarm Optimization (PSO). The control strategy further refines torque management through an adaptive sliding mode control (ASMC) that integrates adaptive laws and a super-twisting sliding mode approach to track the optimal slip ratio. Joint simulations with MATLAB/Simulink and Carsim on low-adhesion, joint, and split road surfaces demonstrate that the strategy quickly and accurately identifies the optimal slip ratio across various road surfaces. This enables the tire slip ratio to approach the optimal value in minimal time, significantly improving vehicle dynamic performance. Compared to conventional sliding mode controllers, the optimized ASMC reduces chattering and improves control precision.</description> <pubDate>2024-10-31</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 769: An Improved Adaptive Sliding Mode Control Approach for Anti-Slip Regulation of Electric Vehicles Based on Optimal Slip Ratio Machines <a href="https://www.mdpi.com/2075-1702/12/11/769">doi: 10.3390/machines12110769</a> Authors: Houzhong Zhang Yiyun Qi Weijian Si Chengyin Zhang To optimize the acceleration performance of independently driven electric vehicles with four in-wheel motors, this paper proposes an anti-slip regulation (ASR) strategy based on dynamic road surface observer for more efficient tracking of the optimal slip ratio and enhanced vehicle acceleration. The method uses the Unscented Kalman Filter (UKF) observer to estimate vehicle speed and calculate the actual slip ratio, while a fuzzy controller based on the Burckhardt tire model identifies road surfaces. The road&amp;rsquo;s peak adhesion coefficient and optimal slip ratio curve are fitted using a Back Propagation Neural Network (BPNN) optimized by Particle Swarm Optimization (PSO). The control strategy further refines torque management through an adaptive sliding mode control (ASMC) that integrates adaptive laws and a super-twisting sliding mode approach to track the optimal slip ratio. Joint simulations with MATLAB/Simulink and Carsim on low-adhesion, joint, and split road surfaces demonstrate that the strategy quickly and accurately identifies the optimal slip ratio across various road surfaces. This enables the tire slip ratio to approach the optimal value in minimal time, significantly improving vehicle dynamic performance. Compared to conventional sliding mode controllers, the optimized ASMC reduces chattering and improves control precision. ]]></content:encoded> <dc:title>An Improved Adaptive Sliding Mode Control Approach for Anti-Slip Regulation of Electric Vehicles Based on Optimal Slip Ratio</dc:title> <dc:creator>Houzhong Zhang</dc:creator> <dc:creator>Yiyun Qi</dc:creator> <dc:creator>Weijian Si</dc:creator> <dc:creator>Chengyin Zhang</dc:creator> <dc:identifier>doi: 10.3390/machines12110769</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-10-31</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-10-31</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>769</prism:startingPage> <prism:doi>10.3390/machines12110769</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/769</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/768"> <title>Machines, Vol. 12, Pages 768: Investigating the Surface Quality of Aramid Honeycomb Materials Through Longitudinal&ndash;Torsional Ultrasonic Milling</title> <link>https://www.mdpi.com/2075-1702/12/11/768</link> <description>During the milling process of aramid honeycomb, residual stresses arise, which will affect the surface quality of the honeycomb. Studies have shown that reasonable processing techniques can reduce residual stresses, indicating a close relationship between residual processing stresses and the processing parameters, such as technique. By investigating the changes in residual stresses after the processing of aramid honeycomb materials, the influence of processing techniques on these changes is analyzed. Leveraging the correlation between residual stresses and surface quality, this study proposes the use of residual stress as an indicator for evaluating processing techniques. The longitudinal&amp;ndash;torsional ultrasonic vibration milling method is applied to the processing of aramid honeycombs. A single-factor experimental approach is adopted, utilizing ABAQUS 2020 software to mimic the longitudinal&amp;ndash;torsional ultrasonic milling process. This study explores the influence patterns of various process parameters on the residual stresses generated during the milling of honeycombs. The simulation results indicate that within the selected range, the residual stress decreases as the tool rotation speed increases, while it increases with the increase in feed rate. The influence of milling depth on residual stress can be negligible. Furthermore, experiments were conducted based on the proposed correlation between residual stress and surface quality. The experimental results show good agreement with the simulation results, indicating that under reasonable process parameters, the residual stress values decrease, thereby improving the milling surface quality of aramid honeycomb materials. Therefore, measuring residual stress can serve as an effective method for evaluating the processing technique.</description> <pubDate>2024-10-31</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 768: Investigating the Surface Quality of Aramid Honeycomb Materials Through Longitudinal&ndash;Torsional Ultrasonic Milling Machines <a href="https://www.mdpi.com/2075-1702/12/11/768">doi: 10.3390/machines12110768</a> Authors: Mingxing Zhang Yang Hong Xiangqun Li Yuzhu Zhang Xiaodong Wang During the milling process of aramid honeycomb, residual stresses arise, which will affect the surface quality of the honeycomb. Studies have shown that reasonable processing techniques can reduce residual stresses, indicating a close relationship between residual processing stresses and the processing parameters, such as technique. By investigating the changes in residual stresses after the processing of aramid honeycomb materials, the influence of processing techniques on these changes is analyzed. Leveraging the correlation between residual stresses and surface quality, this study proposes the use of residual stress as an indicator for evaluating processing techniques. The longitudinal&amp;ndash;torsional ultrasonic vibration milling method is applied to the processing of aramid honeycombs. A single-factor experimental approach is adopted, utilizing ABAQUS 2020 software to mimic the longitudinal&amp;ndash;torsional ultrasonic milling process. This study explores the influence patterns of various process parameters on the residual stresses generated during the milling of honeycombs. The simulation results indicate that within the selected range, the residual stress decreases as the tool rotation speed increases, while it increases with the increase in feed rate. The influence of milling depth on residual stress can be negligible. Furthermore, experiments were conducted based on the proposed correlation between residual stress and surface quality. The experimental results show good agreement with the simulation results, indicating that under reasonable process parameters, the residual stress values decrease, thereby improving the milling surface quality of aramid honeycomb materials. Therefore, measuring residual stress can serve as an effective method for evaluating the processing technique. ]]></content:encoded> <dc:title>Investigating the Surface Quality of Aramid Honeycomb Materials Through Longitudinal&amp;ndash;Torsional Ultrasonic Milling</dc:title> <dc:creator>Mingxing Zhang</dc:creator> <dc:creator>Yang Hong</dc:creator> <dc:creator>Xiangqun Li</dc:creator> <dc:creator>Yuzhu Zhang</dc:creator> <dc:creator>Xiaodong Wang</dc:creator> <dc:identifier>doi: 10.3390/machines12110768</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-10-31</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-10-31</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>768</prism:startingPage> <prism:doi>10.3390/machines12110768</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/768</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/766"> <title>Machines, Vol. 12, Pages 766: A Novel RUL-Centric Data Augmentation Method for Predicting the Remaining Useful Life of Bearings</title> <link>https://www.mdpi.com/2075-1702/12/11/766</link> <description>Maintaining the reliability of rotating machinery in industrial environments entails significant challenges. The objective of this paper is to develop a methodology that can accurately predict the condition of rotating machinery in order to facilitate the implementation of effective preventive maintenance strategies. This article proposed a novel RUL-centric data augmentation method, designated as DF-MDAGRU, for the purpose of predicting the remaining useful life (RUL) of bearings. This model is based on an encoder&amp;ndash;decoder framework that integrates time&amp;ndash;frequency domain feature enhancement with multidimensional dynamic attention gated recurrent units for feature extraction. This method enhances time&amp;ndash;frequency domain features through the Discrete Wavelet Downsampling module (DWD) and Convolutional Fourier Residual Block (CFRB). This method employs a Multiscale Channel Attention Module (MS-CAM) and a Multiscale Convolutional Spatial Attention Mechanism (MSSAM) to extract channel and spatial feature information. Finally, the output predictions are processed through linear regression to achieve the final RUL estimation. Experimental results demonstrate that the proposed method outperforms other state-of-the-art approaches on the FEMETO-ST and XJTU datasets.</description> <pubDate>2024-10-30</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 766: A Novel RUL-Centric Data Augmentation Method for Predicting the Remaining Useful Life of Bearings Machines <a href="https://www.mdpi.com/2075-1702/12/11/766">doi: 10.3390/machines12110766</a> Authors: Miao He Zhonghua Li Fangchao Hu Maintaining the reliability of rotating machinery in industrial environments entails significant challenges. The objective of this paper is to develop a methodology that can accurately predict the condition of rotating machinery in order to facilitate the implementation of effective preventive maintenance strategies. This article proposed a novel RUL-centric data augmentation method, designated as DF-MDAGRU, for the purpose of predicting the remaining useful life (RUL) of bearings. This model is based on an encoder&amp;ndash;decoder framework that integrates time&amp;ndash;frequency domain feature enhancement with multidimensional dynamic attention gated recurrent units for feature extraction. This method enhances time&amp;ndash;frequency domain features through the Discrete Wavelet Downsampling module (DWD) and Convolutional Fourier Residual Block (CFRB). This method employs a Multiscale Channel Attention Module (MS-CAM) and a Multiscale Convolutional Spatial Attention Mechanism (MSSAM) to extract channel and spatial feature information. Finally, the output predictions are processed through linear regression to achieve the final RUL estimation. Experimental results demonstrate that the proposed method outperforms other state-of-the-art approaches on the FEMETO-ST and XJTU datasets. ]]></content:encoded> <dc:title>A Novel RUL-Centric Data Augmentation Method for Predicting the Remaining Useful Life of Bearings</dc:title> <dc:creator>Miao He</dc:creator> <dc:creator>Zhonghua Li</dc:creator> <dc:creator>Fangchao Hu</dc:creator> <dc:identifier>doi: 10.3390/machines12110766</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-10-30</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-10-30</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>766</prism:startingPage> <prism:doi>10.3390/machines12110766</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/766</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/767"> <title>Machines, Vol. 12, Pages 767: Accounting of Deformation Heating During Upsetting of AMg6 Alloy</title> <link>https://www.mdpi.com/2075-1702/12/11/767</link> <description>The AMg6 alloy, which belongs to the Al&amp;ndash;Mg&amp;ndash;Mn system, has high corrosion resistance in various environments, good weldability, and good mechanical properties. During analytical and experimental studies, it was established that the AMg6 alloy, when deformed in the temperature range of 130&amp;ndash;175 &amp;deg;C, has high plastic properties and can withstand large degrees of deformation without destruction and crack formation. At the same time, its microstructure retains the texture of deformation, and the hardness of the alloy increases, which indicates its deformation hardening. The article presents the results of numerical and laboratory experiments on upsetting of 20 mm diameter workpieces from a heating temperature of 20, 130, 260 and 390 &amp;deg;C. Using numerical experiments, the dependences of deformation heating on the upsetting rate and the initial temperature of the workpiece were obtained. Deformation heating should be taken into account when choosing heating before deformation since it can be critical in terms of overburning and loss of plastic properties and corrosion resistance of finished products. The deformation behavior of the AMg6 alloy at a heating temperature of the workpiece up to 130&amp;ndash;175 &amp;deg;C, revealed in this study, indicates the prospects for conducting additional research on the study of changes in the microstructure and mechanical properties of this alloy during warm deformation.</description> <pubDate>2024-10-30</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 767: Accounting of Deformation Heating During Upsetting of AMg6 Alloy Machines <a href="https://www.mdpi.com/2075-1702/12/11/767">doi: 10.3390/machines12110767</a> Authors: Liudmila V. Radionova Dmitry V. Gromov Vitaly A. Bykov The AMg6 alloy, which belongs to the Al&amp;ndash;Mg&amp;ndash;Mn system, has high corrosion resistance in various environments, good weldability, and good mechanical properties. During analytical and experimental studies, it was established that the AMg6 alloy, when deformed in the temperature range of 130&amp;ndash;175 &amp;deg;C, has high plastic properties and can withstand large degrees of deformation without destruction and crack formation. At the same time, its microstructure retains the texture of deformation, and the hardness of the alloy increases, which indicates its deformation hardening. The article presents the results of numerical and laboratory experiments on upsetting of 20 mm diameter workpieces from a heating temperature of 20, 130, 260 and 390 &amp;deg;C. Using numerical experiments, the dependences of deformation heating on the upsetting rate and the initial temperature of the workpiece were obtained. Deformation heating should be taken into account when choosing heating before deformation since it can be critical in terms of overburning and loss of plastic properties and corrosion resistance of finished products. The deformation behavior of the AMg6 alloy at a heating temperature of the workpiece up to 130&amp;ndash;175 &amp;deg;C, revealed in this study, indicates the prospects for conducting additional research on the study of changes in the microstructure and mechanical properties of this alloy during warm deformation. ]]></content:encoded> <dc:title>Accounting of Deformation Heating During Upsetting of AMg6 Alloy</dc:title> <dc:creator>Liudmila V. Radionova</dc:creator> <dc:creator>Dmitry V. Gromov</dc:creator> <dc:creator>Vitaly A. Bykov</dc:creator> <dc:identifier>doi: 10.3390/machines12110767</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-10-30</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-10-30</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>767</prism:startingPage> <prism:doi>10.3390/machines12110767</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/767</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/764"> <title>Machines, Vol. 12, Pages 764: Design of a Path-Tracking Controller with an Adaptive Preview Distance Scheme for Autonomous Vehicles</title> <link>https://www.mdpi.com/2075-1702/12/11/764</link> <description>This paper presents a method to design a path-tracking controller with an adaptive preview distance scheme for autonomous vehicles. Generally, the performance of a path-tracking controller depends on tire&amp;ndash;road friction and is severely deteriorated on low-friction roads. To cope with the problem, it is necessary to design a path-tracking controller that is robust against variations in tire&amp;ndash;road friction. In this paper, a preview function is introduced into the state-space model built for better path-tracking performance. With the preview function, an adaptive preview distance scheme is proposed to adaptively adjust the preview distance according to the variations in tire&amp;ndash;road friction. Front-wheel steering (FWS) and four-wheel steering (4WS) are adopted as actuators for path tracking. With the state-space model, a linear quadratic regulator (LQR) is adopted as a controller design methodology. In the adaptive preview distance scheme, the best preview distance is obtained from simulation for several tire&amp;ndash;road friction conditions. Curve fitting with an exponential function is applied to those preview distances with respect to the tire&amp;ndash;road friction. To verify the performance of the adaptive preview distance scheme under variations in tire&amp;ndash;road friction, a simulation is conducted on vehicle simulation software. From the simulation results, it was shown that the path-tracking controller with an adaptive preview distance scheme presented in this paper was effective for path tracking against variations in tire&amp;ndash;road friction in the peak&amp;rsquo;s center offset, and the settling delays were reduced by 60% and 23%, respectively.</description> <pubDate>2024-10-30</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 764: Design of a Path-Tracking Controller with an Adaptive Preview Distance Scheme for Autonomous Vehicles Machines <a href="https://www.mdpi.com/2075-1702/12/11/764">doi: 10.3390/machines12110764</a> Authors: Manbok Park Seongjin Yim This paper presents a method to design a path-tracking controller with an adaptive preview distance scheme for autonomous vehicles. Generally, the performance of a path-tracking controller depends on tire&amp;ndash;road friction and is severely deteriorated on low-friction roads. To cope with the problem, it is necessary to design a path-tracking controller that is robust against variations in tire&amp;ndash;road friction. In this paper, a preview function is introduced into the state-space model built for better path-tracking performance. With the preview function, an adaptive preview distance scheme is proposed to adaptively adjust the preview distance according to the variations in tire&amp;ndash;road friction. Front-wheel steering (FWS) and four-wheel steering (4WS) are adopted as actuators for path tracking. With the state-space model, a linear quadratic regulator (LQR) is adopted as a controller design methodology. In the adaptive preview distance scheme, the best preview distance is obtained from simulation for several tire&amp;ndash;road friction conditions. Curve fitting with an exponential function is applied to those preview distances with respect to the tire&amp;ndash;road friction. To verify the performance of the adaptive preview distance scheme under variations in tire&amp;ndash;road friction, a simulation is conducted on vehicle simulation software. From the simulation results, it was shown that the path-tracking controller with an adaptive preview distance scheme presented in this paper was effective for path tracking against variations in tire&amp;ndash;road friction in the peak&amp;rsquo;s center offset, and the settling delays were reduced by 60% and 23%, respectively. ]]></content:encoded> <dc:title>Design of a Path-Tracking Controller with an Adaptive Preview Distance Scheme for Autonomous Vehicles</dc:title> <dc:creator>Manbok Park</dc:creator> <dc:creator>Seongjin Yim</dc:creator> <dc:identifier>doi: 10.3390/machines12110764</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-10-30</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-10-30</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>764</prism:startingPage> <prism:doi>10.3390/machines12110764</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/764</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/765"> <title>Machines, Vol. 12, Pages 765: Prediction and Analysis of Borosilicate Glass Surface Deformation Induced by Flame Jet</title> <link>https://www.mdpi.com/2075-1702/12/11/765</link> <description>To address the issues of low processing efficiency, poor forming accuracy, and internal damage in glass material processing, this study proposes the use of flame jet forming. However, the mechanism of flame jet processing requires further elucidation. This research investigates the relationship between the indentation morphology on the glass surface and the inlet velocity of the flame jet. A theoretical model was established through mathematical analysis to reflect this relationship. The model&amp;rsquo;s accuracy was validated using numerical simulation methods. By comparing experimental data with theoretical model results, surface tension was incorporated, and the model was iteratively optimized using MATLAB R2024a. The final optimized model demonstrated an absolute error range of 0.009 to 0.069 mm. This study confirms the feasibility of flame jet processing and enriches the understanding of its mechanism, providing a novel, efficient, and precise method for processing glass materials.</description> <pubDate>2024-10-30</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 765: Prediction and Analysis of Borosilicate Glass Surface Deformation Induced by Flame Jet Machines <a href="https://www.mdpi.com/2075-1702/12/11/765">doi: 10.3390/machines12110765</a> Authors: Biling Wang Yutang Zhai Xinming Zhang Xinxin Qi Weijie Fu To address the issues of low processing efficiency, poor forming accuracy, and internal damage in glass material processing, this study proposes the use of flame jet forming. However, the mechanism of flame jet processing requires further elucidation. This research investigates the relationship between the indentation morphology on the glass surface and the inlet velocity of the flame jet. A theoretical model was established through mathematical analysis to reflect this relationship. The model&amp;rsquo;s accuracy was validated using numerical simulation methods. By comparing experimental data with theoretical model results, surface tension was incorporated, and the model was iteratively optimized using MATLAB R2024a. The final optimized model demonstrated an absolute error range of 0.009 to 0.069 mm. This study confirms the feasibility of flame jet processing and enriches the understanding of its mechanism, providing a novel, efficient, and precise method for processing glass materials. ]]></content:encoded> <dc:title>Prediction and Analysis of Borosilicate Glass Surface Deformation Induced by Flame Jet</dc:title> <dc:creator>Biling Wang</dc:creator> <dc:creator>Yutang Zhai</dc:creator> <dc:creator>Xinming Zhang</dc:creator> <dc:creator>Xinxin Qi</dc:creator> <dc:creator>Weijie Fu</dc:creator> <dc:identifier>doi: 10.3390/machines12110765</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-10-30</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-10-30</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>765</prism:startingPage> <prism:doi>10.3390/machines12110765</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/765</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/763"> <title>Machines, Vol. 12, Pages 763: An Optimization Method for Multi-Robot Automatic Welding Control Based on Particle Swarm Genetic Algorithm</title> <link>https://www.mdpi.com/2075-1702/12/11/763</link> <description>This paper introduces an optimization method for multi-robot automated control welding based on a Particle Swarm Genetic Algorithm (PSGA), aiming to address issues such as high costs, large footprint, and excessive production cycles in multi-robot welding production lines. The method first constructs a multi-axis robotic kinematic model to provide constraint conditions. Then, the PSO (particle swarm optimization) algorithm, which integrates penalty functions into the fitness evaluation, is used to determine the optimal welding path by simulating collective behavior within a group. The GA (genetic algorithm) encodes the position of the welding robot bases into chromosomes to find the optimal layout for coordinated control of multiple robots. The entire process is optimized according to welding standards and requirements. Additionally, a comprehensive production line performance estimation model was used to quantitatively analyze the new scheme. The results show that the optimized production line&amp;rsquo;s balance rate increased by 10%, the balance loss rate decreased by 10%, the smoothness index increased by 37.8%, the space costs reduced by 44.4%, the equipment demand reduced by 41.1%, the labor demand reduced by 50%, the total costs reduced by 10%, and the average product cycle time was reduced by 5.07 s. Finally, we tested the algorithm in various complex scenarios and compared its performance against mainstream algorithms within the context of this study. The results demonstrated that the optimized production line significantly improved efficiency while maintaining safety standards.</description> <pubDate>2024-10-30</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 763: An Optimization Method for Multi-Robot Automatic Welding Control Based on Particle Swarm Genetic Algorithm Machines <a href="https://www.mdpi.com/2075-1702/12/11/763">doi: 10.3390/machines12110763</a> Authors: Lu Chen Jie Tan Tianci Wu Zengxin Tan Guobo Yuan Yuhao Yang Chiang Liu Haoyu Zhou Weisi Xie Yue Xiu Gun Li This paper introduces an optimization method for multi-robot automated control welding based on a Particle Swarm Genetic Algorithm (PSGA), aiming to address issues such as high costs, large footprint, and excessive production cycles in multi-robot welding production lines. The method first constructs a multi-axis robotic kinematic model to provide constraint conditions. Then, the PSO (particle swarm optimization) algorithm, which integrates penalty functions into the fitness evaluation, is used to determine the optimal welding path by simulating collective behavior within a group. The GA (genetic algorithm) encodes the position of the welding robot bases into chromosomes to find the optimal layout for coordinated control of multiple robots. The entire process is optimized according to welding standards and requirements. Additionally, a comprehensive production line performance estimation model was used to quantitatively analyze the new scheme. The results show that the optimized production line&amp;rsquo;s balance rate increased by 10%, the balance loss rate decreased by 10%, the smoothness index increased by 37.8%, the space costs reduced by 44.4%, the equipment demand reduced by 41.1%, the labor demand reduced by 50%, the total costs reduced by 10%, and the average product cycle time was reduced by 5.07 s. Finally, we tested the algorithm in various complex scenarios and compared its performance against mainstream algorithms within the context of this study. The results demonstrated that the optimized production line significantly improved efficiency while maintaining safety standards. ]]></content:encoded> <dc:title>An Optimization Method for Multi-Robot Automatic Welding Control Based on Particle Swarm Genetic Algorithm</dc:title> <dc:creator>Lu Chen</dc:creator> <dc:creator>Jie Tan</dc:creator> <dc:creator>Tianci Wu</dc:creator> <dc:creator>Zengxin Tan</dc:creator> <dc:creator>Guobo Yuan</dc:creator> <dc:creator>Yuhao Yang</dc:creator> <dc:creator>Chiang Liu</dc:creator> <dc:creator>Haoyu Zhou</dc:creator> <dc:creator>Weisi Xie</dc:creator> <dc:creator>Yue Xiu</dc:creator> <dc:creator>Gun Li</dc:creator> <dc:identifier>doi: 10.3390/machines12110763</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-10-30</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-10-30</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>763</prism:startingPage> <prism:doi>10.3390/machines12110763</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/763</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/762"> <title>Machines, Vol. 12, Pages 762: Effective Machine Learning Solution for State Classification and Productivity Identification: Case of Pneumatic Pressing Machine</title> <link>https://www.mdpi.com/2075-1702/12/11/762</link> <description>The fourth industrial revolution (Industry 4.0) brought significant changes in manufacturing, driven by technologies like artificial intelligence (AI), Internet of Things (IoT), 5G, robotics, and big data analytics. For industries to remain competitive, the primary goals must be the improvement of the efficiency and safety of machinery, the reduction of production costs, and the enhancement of product quality. Predictive maintenance (PdM) utilizes historical data and AI models to diagnose equipment&amp;rsquo;s health and predict the remaining useful life (RUL), providing critical insights for machinery effectiveness and product manufacturing. This prediction is a critical strategy to maximize the useful life of equipment, especially in large-scale and important infostructures. This study focuses on developing an unsupervised machine state-classification solution utilizing real-world industrial measurements collected from a pneumatic pressing machine. Unsupervised machine learning (ML) models were tested to diagnose and output the working state of the pressing machine at each given point (offline, idle, pressing, defective). Our research contributes to extracting valuable insights regarding real-world industrial settings for PdM and production efficiency using unsupervised ML, promoting operation safety, cost reduction, and productivity enhancement in modern industries.</description> <pubDate>2024-10-30</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 762: Effective Machine Learning Solution for State Classification and Productivity Identification: Case of Pneumatic Pressing Machine Machines <a href="https://www.mdpi.com/2075-1702/12/11/762">doi: 10.3390/machines12110762</a> Authors: Alexandros Kolokas Panagiotis Mallioris Michalis Koutsiantzis Christos Bialas Dimitrios Bechtsis Evangelos Diamantis The fourth industrial revolution (Industry 4.0) brought significant changes in manufacturing, driven by technologies like artificial intelligence (AI), Internet of Things (IoT), 5G, robotics, and big data analytics. For industries to remain competitive, the primary goals must be the improvement of the efficiency and safety of machinery, the reduction of production costs, and the enhancement of product quality. Predictive maintenance (PdM) utilizes historical data and AI models to diagnose equipment&amp;rsquo;s health and predict the remaining useful life (RUL), providing critical insights for machinery effectiveness and product manufacturing. This prediction is a critical strategy to maximize the useful life of equipment, especially in large-scale and important infostructures. This study focuses on developing an unsupervised machine state-classification solution utilizing real-world industrial measurements collected from a pneumatic pressing machine. Unsupervised machine learning (ML) models were tested to diagnose and output the working state of the pressing machine at each given point (offline, idle, pressing, defective). Our research contributes to extracting valuable insights regarding real-world industrial settings for PdM and production efficiency using unsupervised ML, promoting operation safety, cost reduction, and productivity enhancement in modern industries. ]]></content:encoded> <dc:title>Effective Machine Learning Solution for State Classification and Productivity Identification: Case of Pneumatic Pressing Machine</dc:title> <dc:creator>Alexandros Kolokas</dc:creator> <dc:creator>Panagiotis Mallioris</dc:creator> <dc:creator>Michalis Koutsiantzis</dc:creator> <dc:creator>Christos Bialas</dc:creator> <dc:creator>Dimitrios Bechtsis</dc:creator> <dc:creator>Evangelos Diamantis</dc:creator> <dc:identifier>doi: 10.3390/machines12110762</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-10-30</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-10-30</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>762</prism:startingPage> <prism:doi>10.3390/machines12110762</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/762</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/761"> <title>Machines, Vol. 12, Pages 761: Innovative Electrostatic Precipitator Solutions for Efficient Removal of Fine Particulate Matter: Enhancing Performance and Energy Efficiency</title> <link>https://www.mdpi.com/2075-1702/12/11/761</link> <description>The removal of particulate matter (PM) from air streams is essential for advancing environmental technologies and safeguarding public health. This study explores the performance of an electrostatic precipitator (ESP) in eliminating fine and ultra-fine PM under varied experimental conditions. It uniquely examines the influence of PM size and feed rate on ESP removal efficiency. The system&amp;rsquo;s use of low voltages enhances energy sustainability, while its innovative design improves corona discharge, leading to significant reductions in fine and ultra-fine PM emissions. Plants using electrical devices are increasingly being incorporated into material processing lines to reduce pollution in the surrounding work area, as well as to collect particle emissions in the atmosphere. It is also possible to recycle some raw materials in this way with low energy consumption. This cleaning technology increases the added value of industrial equipment, which affects its competitiveness and its impact on sustainable manufacturing. The experimental results indicate a steady electrostatic field voltage of 15.1 kilovolts, with an airflow maintained at 0.8 m/s through a doser at 2.5 bar, eliminating the need for a fan. The PM feed rate varied between 2 and 20 mm/h, with six trials conducted to ensure the data were consistent. Preliminary studies devoid of ESP intervention demonstrated little PM removal, since buildup on the chamber walls distorted the results. The installation of the ESF markedly enhanced the removal efficiency, achieving up to 95.5%. Further analysis revealed that ESP performance depended on PM concentration in the agglomeration chamber, achieving a clearance rate exceeding 98% under optimal conditions. Fine PM (0.35 to 8.7 &amp;micro;m) was more efficiently removed than ultra-fine PM (0.2 to 0.35 &amp;micro;m). The highest removal efficiency was observed at a feed rate of 0.962 mg/s, while the lowest occurred at 0.385 mg/s. A strong positive correlation between particle concentration and removal efficiency (Pearson value up to 0.829) was observed, particularly at feed rates of 0.128, 0.641, and 1.283 mg/s. The study&amp;rsquo;s findings confirm that the ESP is highly effective in removing particulate matter, particularly fine and ultra-fine particles, with an optimal feed rate, significantly enhancing the system&amp;rsquo;s performance.</description> <pubDate>2024-10-30</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 761: Innovative Electrostatic Precipitator Solutions for Efficient Removal of Fine Particulate Matter: Enhancing Performance and Energy Efficiency Machines <a href="https://www.mdpi.com/2075-1702/12/11/761">doi: 10.3390/machines12110761</a> Authors: Edgar Sokolovskij Art奴ras Kilikevi膷ius Aleksandras Chlebnikovas Jonas Matijo拧ius Darius Vainorius The removal of particulate matter (PM) from air streams is essential for advancing environmental technologies and safeguarding public health. This study explores the performance of an electrostatic precipitator (ESP) in eliminating fine and ultra-fine PM under varied experimental conditions. It uniquely examines the influence of PM size and feed rate on ESP removal efficiency. The system&amp;rsquo;s use of low voltages enhances energy sustainability, while its innovative design improves corona discharge, leading to significant reductions in fine and ultra-fine PM emissions. Plants using electrical devices are increasingly being incorporated into material processing lines to reduce pollution in the surrounding work area, as well as to collect particle emissions in the atmosphere. It is also possible to recycle some raw materials in this way with low energy consumption. This cleaning technology increases the added value of industrial equipment, which affects its competitiveness and its impact on sustainable manufacturing. The experimental results indicate a steady electrostatic field voltage of 15.1 kilovolts, with an airflow maintained at 0.8 m/s through a doser at 2.5 bar, eliminating the need for a fan. The PM feed rate varied between 2 and 20 mm/h, with six trials conducted to ensure the data were consistent. Preliminary studies devoid of ESP intervention demonstrated little PM removal, since buildup on the chamber walls distorted the results. The installation of the ESF markedly enhanced the removal efficiency, achieving up to 95.5%. Further analysis revealed that ESP performance depended on PM concentration in the agglomeration chamber, achieving a clearance rate exceeding 98% under optimal conditions. Fine PM (0.35 to 8.7 &amp;micro;m) was more efficiently removed than ultra-fine PM (0.2 to 0.35 &amp;micro;m). The highest removal efficiency was observed at a feed rate of 0.962 mg/s, while the lowest occurred at 0.385 mg/s. A strong positive correlation between particle concentration and removal efficiency (Pearson value up to 0.829) was observed, particularly at feed rates of 0.128, 0.641, and 1.283 mg/s. The study&amp;rsquo;s findings confirm that the ESP is highly effective in removing particulate matter, particularly fine and ultra-fine particles, with an optimal feed rate, significantly enhancing the system&amp;rsquo;s performance. ]]></content:encoded> <dc:title>Innovative Electrostatic Precipitator Solutions for Efficient Removal of Fine Particulate Matter: Enhancing Performance and Energy Efficiency</dc:title> <dc:creator>Edgar Sokolovskij</dc:creator> <dc:creator>Art奴ras Kilikevi膷ius</dc:creator> <dc:creator>Aleksandras Chlebnikovas</dc:creator> <dc:creator>Jonas Matijo拧ius</dc:creator> <dc:creator>Darius Vainorius</dc:creator> <dc:identifier>doi: 10.3390/machines12110761</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-10-30</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-10-30</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>761</prism:startingPage> <prism:doi>10.3390/machines12110761</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/761</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/760"> <title>Machines, Vol. 12, Pages 760: I3oT (Industrializable Industrial Internet of Things) Tool for Continuous Improvement in Production Line Efficiency by Means of Sub-Bottleneck Detection Method</title> <link>https://www.mdpi.com/2075-1702/12/11/760</link> <description>The present paper shows how to develop an I3oT (Industrializable Industrial Internet of Things) tool for continuous improvement in production line efficiency by means of the sub-bottleneck detection method. There is a large amount of scientific literature related to the detection of bottlenecks in production lines. However, there is no scientific literature that develops tools to improve production lines based on the bottlenecks that go beyond rebalancing tasks. This article explores the concept of a sub-bottleneck. In order to detect sub-bottlenecks in a massive way, the use of one of the I3oT (Industrializable Industrial Internet of Things) tools developed in our previous work, the mini-terms, is proposed. These mini-terms use the existing sensors for the normal operation of the production lines to measure the sub-cycle times and use them to predict the deterioration of the machine components found in the production lines. The sub-bottleneck algorithms proposed are used in two real twin lines at the Ford manufacturing plant in Almussafes (Valencia), the (3LH) and (3RH), to show how the lines can be continuously improved by means of sub-bottleneck detection.</description> <pubDate>2024-10-29</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 760: I3oT (Industrializable Industrial Internet of Things) Tool for Continuous Improvement in Production Line Efficiency by Means of Sub-Bottleneck Detection Method Machines <a href="https://www.mdpi.com/2075-1702/12/11/760">doi: 10.3390/machines12110760</a> Authors: Javier Llopis Antonio Lacasa Nicol谩s Mont茅s Eduardo Garcia The present paper shows how to develop an I3oT (Industrializable Industrial Internet of Things) tool for continuous improvement in production line efficiency by means of the sub-bottleneck detection method. There is a large amount of scientific literature related to the detection of bottlenecks in production lines. However, there is no scientific literature that develops tools to improve production lines based on the bottlenecks that go beyond rebalancing tasks. This article explores the concept of a sub-bottleneck. In order to detect sub-bottlenecks in a massive way, the use of one of the I3oT (Industrializable Industrial Internet of Things) tools developed in our previous work, the mini-terms, is proposed. These mini-terms use the existing sensors for the normal operation of the production lines to measure the sub-cycle times and use them to predict the deterioration of the machine components found in the production lines. The sub-bottleneck algorithms proposed are used in two real twin lines at the Ford manufacturing plant in Almussafes (Valencia), the (3LH) and (3RH), to show how the lines can be continuously improved by means of sub-bottleneck detection. ]]></content:encoded> <dc:title>I3oT (Industrializable Industrial Internet of Things) Tool for Continuous Improvement in Production Line Efficiency by Means of Sub-Bottleneck Detection Method</dc:title> <dc:creator>Javier Llopis</dc:creator> <dc:creator>Antonio Lacasa</dc:creator> <dc:creator>Nicol谩s Mont茅s</dc:creator> <dc:creator>Eduardo Garcia</dc:creator> <dc:identifier>doi: 10.3390/machines12110760</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-10-29</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-10-29</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>760</prism:startingPage> <prism:doi>10.3390/machines12110760</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/760</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/759"> <title>Machines, Vol. 12, Pages 759: Design and Implementation of Digital Twin Factory Synchronized in Real-Time Using MQTT</title> <link>https://www.mdpi.com/2075-1702/12/11/759</link> <description>As information technology progresses, the need for digital transformation within the industrial sector has become increasingly apparent, and digital twin technology has emerged as a significant trend in manufacturing. Digital twins synchronize physical and digital environments, overcoming spatial and temporal limitations to create various added values that are unattainable in reality. This paper presents a model that integrates digital twin technology with production and operational technologies at manufacturing sites, enabling remote, centrally controlled manufacturing services that transcend physical constraints. Specifically, by utilizing Message Queuing Telemetry Transport (MQTT) for real-time synchronization, this approach ensures efficient and timely data transfer between physical and digital environments. While traditional approaches often encounter challenges due to high investment costs and design complexities, this paper proposes a cost-effective and practical solution that reflects actual factory conditions.</description> <pubDate>2024-10-29</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 759: Design and Implementation of Digital Twin Factory Synchronized in Real-Time Using MQTT Machines <a href="https://www.mdpi.com/2075-1702/12/11/759">doi: 10.3390/machines12110759</a> Authors: Yechang Cho Sang Do Noh As information technology progresses, the need for digital transformation within the industrial sector has become increasingly apparent, and digital twin technology has emerged as a significant trend in manufacturing. Digital twins synchronize physical and digital environments, overcoming spatial and temporal limitations to create various added values that are unattainable in reality. This paper presents a model that integrates digital twin technology with production and operational technologies at manufacturing sites, enabling remote, centrally controlled manufacturing services that transcend physical constraints. Specifically, by utilizing Message Queuing Telemetry Transport (MQTT) for real-time synchronization, this approach ensures efficient and timely data transfer between physical and digital environments. While traditional approaches often encounter challenges due to high investment costs and design complexities, this paper proposes a cost-effective and practical solution that reflects actual factory conditions. ]]></content:encoded> <dc:title>Design and Implementation of Digital Twin Factory Synchronized in Real-Time Using MQTT</dc:title> <dc:creator>Yechang Cho</dc:creator> <dc:creator>Sang Do Noh</dc:creator> <dc:identifier>doi: 10.3390/machines12110759</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-10-29</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-10-29</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>759</prism:startingPage> <prism:doi>10.3390/machines12110759</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/759</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/758"> <title>Machines, Vol. 12, Pages 758: Low-Cost High-Voltage Power Supply for Hydraulically Amplified Self-Healing Electrostatic Applications</title> <link>https://www.mdpi.com/2075-1702/12/11/758</link> <description>HASEL (Hydraulically Amplified Self-Healing Electrostatic) actuators have gathered momentum in recent years; they are made of very-low-cost materials, making it easy for anyone to develop their own actuators, and they are &amp;ldquo;soft&amp;rdquo; and can achieve tasks that are very difficult to complete with traditional rigid actuators, e.g., grasping soft objects. Unfortunately, HASEL actuators are driven by high-voltage (HV) power supplies, which are expensive to control accurately and difficult to scale up for multichannel applications, e.g., prostheses. This paper presents a low-cost HV power supply designed for HASEL applications that generates 2&amp;ndash;10 kV DC at 5% of the cost of the existing HV power supplies used in HASEL actuators. At the core of our design, there is a new control strategy based on controlling the charging and discharging of the actuator from the supply&amp;rsquo;s low-voltage (LV) side rather than switching the HV side with expensive HV optocouplers. Discharge is achieved via a secondary transformer and multiplier circuit, generating a negative HV output capable of discharging the HASEL effectively and safely up to 10 kV.</description> <pubDate>2024-10-27</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 758: Low-Cost High-Voltage Power Supply for Hydraulically Amplified Self-Healing Electrostatic Applications Machines <a href="https://www.mdpi.com/2075-1702/12/11/758">doi: 10.3390/machines12110758</a> Authors: Levi Tynan Upul Gunawardana Ranjith Liyanapathirana Osura Perera Daniele Esposito Jessica Centracchio Gaetano Gargiulo HASEL (Hydraulically Amplified Self-Healing Electrostatic) actuators have gathered momentum in recent years; they are made of very-low-cost materials, making it easy for anyone to develop their own actuators, and they are &amp;ldquo;soft&amp;rdquo; and can achieve tasks that are very difficult to complete with traditional rigid actuators, e.g., grasping soft objects. Unfortunately, HASEL actuators are driven by high-voltage (HV) power supplies, which are expensive to control accurately and difficult to scale up for multichannel applications, e.g., prostheses. This paper presents a low-cost HV power supply designed for HASEL applications that generates 2&amp;ndash;10 kV DC at 5% of the cost of the existing HV power supplies used in HASEL actuators. At the core of our design, there is a new control strategy based on controlling the charging and discharging of the actuator from the supply&amp;rsquo;s low-voltage (LV) side rather than switching the HV side with expensive HV optocouplers. Discharge is achieved via a secondary transformer and multiplier circuit, generating a negative HV output capable of discharging the HASEL effectively and safely up to 10 kV. ]]></content:encoded> <dc:title>Low-Cost High-Voltage Power Supply for Hydraulically Amplified Self-Healing Electrostatic Applications</dc:title> <dc:creator>Levi Tynan</dc:creator> <dc:creator>Upul Gunawardana</dc:creator> <dc:creator>Ranjith Liyanapathirana</dc:creator> <dc:creator>Osura Perera</dc:creator> <dc:creator>Daniele Esposito</dc:creator> <dc:creator>Jessica Centracchio</dc:creator> <dc:creator>Gaetano Gargiulo</dc:creator> <dc:identifier>doi: 10.3390/machines12110758</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-10-27</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-10-27</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>758</prism:startingPage> <prism:doi>10.3390/machines12110758</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/758</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/757"> <title>Machines, Vol. 12, Pages 757: Hyper CLS-Data-Based Robotic Interface and Its Application to Intelligent Peg-in-Hole Task Robot Incorporating a CNN Model for Defect Detection</title> <link>https://www.mdpi.com/2075-1702/12/11/757</link> <description>Various types of numerical control (NC) machine tools can be standardly operated and controlled based on NC data that can be easily generated using widespread CAD/CAM systems. On the other hand, the operation environments of industrial robots still depend on conventional teaching and playback systems provided by the makers, so it seems that they have not been standardized and unified like NC machine tools yet. Additionally, robotic functional extensions, e.g., the easy implementation of a machine learning model, such as a convolutional neural network (CNN), a visual feedback controller, cooperative control for multiple robots, and so on, has not been sufficiently realized yet. In this paper, a hyper cutter location source (HCLS)-data-based robotic interface is proposed to cope with the issues. Due to the HCLS-data-based robot interface, the robotic control sequence can be visually and unifiedly described as NC codes. In addition, a VGG19-based CNN model for defect detection, whose classification accuracy is over 99% and average time for forward calculation is 70 ms, can be systematically incorporated into a robotic control application that handles multiple robots. The effectiveness and validity of the proposed system are demonstrated through a cooperative pick and place task using three small-sized industrial robot MG400s and a peg-in-hole task while checking undesirable defects in workpieces with a CNN model without using any programmable logic controller (PLC). The specifications of the PC used for the experiments are CPU: Intel(R) Core(TM) i9-10850K CPU 3.60 GHz, GPU: NVIDIA GeForce RTX 3090, Main memory: 64 GB.</description> <pubDate>2024-10-26</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 757: Hyper CLS-Data-Based Robotic Interface and Its Application to Intelligent Peg-in-Hole Task Robot Incorporating a CNN Model for Defect Detection Machines <a href="https://www.mdpi.com/2075-1702/12/11/757">doi: 10.3390/machines12110757</a> Authors: Fusaomi Nagata Ryoma Abe Shingo Sakata Keigo Watanabe Maki K. Habib Various types of numerical control (NC) machine tools can be standardly operated and controlled based on NC data that can be easily generated using widespread CAD/CAM systems. On the other hand, the operation environments of industrial robots still depend on conventional teaching and playback systems provided by the makers, so it seems that they have not been standardized and unified like NC machine tools yet. Additionally, robotic functional extensions, e.g., the easy implementation of a machine learning model, such as a convolutional neural network (CNN), a visual feedback controller, cooperative control for multiple robots, and so on, has not been sufficiently realized yet. In this paper, a hyper cutter location source (HCLS)-data-based robotic interface is proposed to cope with the issues. Due to the HCLS-data-based robot interface, the robotic control sequence can be visually and unifiedly described as NC codes. In addition, a VGG19-based CNN model for defect detection, whose classification accuracy is over 99% and average time for forward calculation is 70 ms, can be systematically incorporated into a robotic control application that handles multiple robots. The effectiveness and validity of the proposed system are demonstrated through a cooperative pick and place task using three small-sized industrial robot MG400s and a peg-in-hole task while checking undesirable defects in workpieces with a CNN model without using any programmable logic controller (PLC). The specifications of the PC used for the experiments are CPU: Intel(R) Core(TM) i9-10850K CPU 3.60 GHz, GPU: NVIDIA GeForce RTX 3090, Main memory: 64 GB. ]]></content:encoded> <dc:title>Hyper CLS-Data-Based Robotic Interface and Its Application to Intelligent Peg-in-Hole Task Robot Incorporating a CNN Model for Defect Detection</dc:title> <dc:creator>Fusaomi Nagata</dc:creator> <dc:creator>Ryoma Abe</dc:creator> <dc:creator>Shingo Sakata</dc:creator> <dc:creator>Keigo Watanabe</dc:creator> <dc:creator>Maki K. Habib</dc:creator> <dc:identifier>doi: 10.3390/machines12110757</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-10-26</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-10-26</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>757</prism:startingPage> <prism:doi>10.3390/machines12110757</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/757</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/756"> <title>Machines, Vol. 12, Pages 756: A Force Control Method Integrating Human Skills for Complex Surface Finishing</title> <link>https://www.mdpi.com/2075-1702/12/11/756</link> <description>Force control is one of the core modules for surface finishing such as grinding, polishing and sanding. However, the current force control methods based on human skills lack in-depth analysis of data patterns or are only applicable to flat surfaces. In addition, surface finishing is mainly performed by hand, resulting in low processing efficiency and poor product consistency. Therefore, this paper proposes a force control method that incorporates human skills to achieve relatively accurate force skill transfer and complex surface finishing. Firstly, human skills consisting of the force skill and the motion skill are learned. The force skill is used to generate the desired force. Then, a series of discrete poses are obtained based on human demonstration and combined with the motion skill to generate the desired trajectory. Finally, a computed-torque impedance control method is proposed to achieve relatively accurate force skill transfer and complex surface finishing by incorporating the desired trajectory and the desired force. The experiments are conducted on a platform composed of a 7-DOF collaborative robot manipulator from Franka Emika and a complex violin surface. The results demonstrate that the proposed force control method can achieve relatively accurate force skill transfer and improve the surface quality of the workpiece.</description> <pubDate>2024-10-26</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 756: A Force Control Method Integrating Human Skills for Complex Surface Finishing Machines <a href="https://www.mdpi.com/2075-1702/12/11/756">doi: 10.3390/machines12110756</a> Authors: Kang Min Fenglei Ni Zhaoyang Chen Hong Liu Force control is one of the core modules for surface finishing such as grinding, polishing and sanding. However, the current force control methods based on human skills lack in-depth analysis of data patterns or are only applicable to flat surfaces. In addition, surface finishing is mainly performed by hand, resulting in low processing efficiency and poor product consistency. Therefore, this paper proposes a force control method that incorporates human skills to achieve relatively accurate force skill transfer and complex surface finishing. Firstly, human skills consisting of the force skill and the motion skill are learned. The force skill is used to generate the desired force. Then, a series of discrete poses are obtained based on human demonstration and combined with the motion skill to generate the desired trajectory. Finally, a computed-torque impedance control method is proposed to achieve relatively accurate force skill transfer and complex surface finishing by incorporating the desired trajectory and the desired force. The experiments are conducted on a platform composed of a 7-DOF collaborative robot manipulator from Franka Emika and a complex violin surface. The results demonstrate that the proposed force control method can achieve relatively accurate force skill transfer and improve the surface quality of the workpiece. ]]></content:encoded> <dc:title>A Force Control Method Integrating Human Skills for Complex Surface Finishing</dc:title> <dc:creator>Kang Min</dc:creator> <dc:creator>Fenglei Ni</dc:creator> <dc:creator>Zhaoyang Chen</dc:creator> <dc:creator>Hong Liu</dc:creator> <dc:identifier>doi: 10.3390/machines12110756</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-10-26</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-10-26</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>756</prism:startingPage> <prism:doi>10.3390/machines12110756</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/756</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <item rdf:about="https://www.mdpi.com/2075-1702/12/11/754"> <title>Machines, Vol. 12, Pages 754: Friction in Adhesive Contact Between a Rough Hard Indenter and Smooth Soft Elastomer Layer</title> <link>https://www.mdpi.com/2075-1702/12/11/754</link> <description>The friction between a hard steel indenter and a soft elastomer is studied experimentally. To investigate the influence of roughness, a series of experiments was conducted utilizing an indenter with varying degrees of surface roughness. There is a strong adhesive interaction between the contacting bodies and the friction force is proportional to the real contact area. It has been shown that as the amplitude of roughness increases, the friction force initially rises due to the deformable elastomer filling the gaps between the roughness features, thereby increasing the real contact area. An increase in the roughness amplitude results in a more regular dependence of the friction force on the tangential displacement of the indenter. High-amplitude roughness prevents the propagation of elastic deformation waves (Schallamach waves) within the contact, which are responsible for the establishment of a &amp;ldquo;stick&amp;ndash;slip&amp;rdquo; type of friction regime. The results of this study are of interest for technical applications in mechanical engineering, particularly those involving the production of rubber seals.</description> <pubDate>2024-10-25</pubDate> <content:encoded><![CDATA[ Machines, Vol. 12, Pages 754: Friction in Adhesive Contact Between a Rough Hard Indenter and Smooth Soft Elastomer Layer Machines <a href="https://www.mdpi.com/2075-1702/12/11/754">doi: 10.3390/machines12110754</a> Authors: Iakov A. Lyashenko Thao H. Pham Valentin L. Popov The friction between a hard steel indenter and a soft elastomer is studied experimentally. To investigate the influence of roughness, a series of experiments was conducted utilizing an indenter with varying degrees of surface roughness. There is a strong adhesive interaction between the contacting bodies and the friction force is proportional to the real contact area. It has been shown that as the amplitude of roughness increases, the friction force initially rises due to the deformable elastomer filling the gaps between the roughness features, thereby increasing the real contact area. An increase in the roughness amplitude results in a more regular dependence of the friction force on the tangential displacement of the indenter. High-amplitude roughness prevents the propagation of elastic deformation waves (Schallamach waves) within the contact, which are responsible for the establishment of a &amp;ldquo;stick&amp;ndash;slip&amp;rdquo; type of friction regime. The results of this study are of interest for technical applications in mechanical engineering, particularly those involving the production of rubber seals. ]]></content:encoded> <dc:title>Friction in Adhesive Contact Between a Rough Hard Indenter and Smooth Soft Elastomer Layer</dc:title> <dc:creator>Iakov A. Lyashenko</dc:creator> <dc:creator>Thao H. Pham</dc:creator> <dc:creator>Valentin L. Popov</dc:creator> <dc:identifier>doi: 10.3390/machines12110754</dc:identifier> <dc:source>Machines</dc:source> <dc:date>2024-10-25</dc:date> <prism:publicationName>Machines</prism:publicationName> <prism:publicationDate>2024-10-25</prism:publicationDate> <prism:volume>12</prism:volume> <prism:number>11</prism:number> <prism:section>Article</prism:section> <prism:startingPage>754</prism:startingPage> <prism:doi>10.3390/machines12110754</prism:doi> <prism:url>https://www.mdpi.com/2075-1702/12/11/754</prism:url> <cc:license rdf:resource="CC BY 4.0"/> </item> <cc:License rdf:about="https://creativecommons.org/licenses/by/4.0/"> <cc:permits rdf:resource="https://creativecommons.org/ns#Reproduction" /> <cc:permits rdf:resource="https://creativecommons.org/ns#Distribution" /> <cc:permits rdf:resource="https://creativecommons.org/ns#DerivativeWorks" /> </cc:License> </rdf:RDF>