Pub Date : 2025-07-10DOI: 10.1016/j.mechatronics.2025.103382
Oleg Sergiyenko , José A. Núñez-López , Vera Tyrsa , Rubén Alaniz-Plata , Oscar M. Pérez-Landeros , César Selpúlveda-Valdez , Wendy Flores-Fuentes , Julio C. Rodríguez-Quiñonez , Fabian N. Murrieta-Rico , Vladimir Kartashov , Marina Kolendovska
This study aimed to address the issue of laser ray spatial positioning to mitigate discontinuities in the dynamics caused by nonsmooth friction effects by the direct application of control theory with improved friction compensation. Analyzing physical phenomena on micro-relieved surfaces through SEM methods, the obtained data about surface characteristics helps synthesize a corresponding control law for the laser positioner and conduct its stability analysis. This work considers a patented laser scanning system incorporating a laser positioning mechanism with inherent friction. SEM micrograph analysis of the friction zone was conducted to compare microscopic imperfections of steel surfaces, which helped infer the dynamics of an internal variable ‘z’ in the friction model and determine a reference value for control synthesis. A nonlinear control algorithm was proposed to compensate for friction to enhance positioning accuracy. The global asymptotic stability of the system was proven using Lyapunov’s direct method and Barbalat’s lemma. Experimental implementation on an STM32 board demonstrated a significant reduction in the uncertainty associated with sensing 3D coordinates using the friction-compensated laser scanning system.
{"title":"3D coordinate sensing with nonsmooth friction dynamical discontinuities compensation in laser scanning system","authors":"Oleg Sergiyenko , José A. Núñez-López , Vera Tyrsa , Rubén Alaniz-Plata , Oscar M. Pérez-Landeros , César Selpúlveda-Valdez , Wendy Flores-Fuentes , Julio C. Rodríguez-Quiñonez , Fabian N. Murrieta-Rico , Vladimir Kartashov , Marina Kolendovska","doi":"10.1016/j.mechatronics.2025.103382","DOIUrl":"10.1016/j.mechatronics.2025.103382","url":null,"abstract":"<div><div>This study aimed to address the issue of laser ray spatial positioning to mitigate discontinuities in the dynamics caused by nonsmooth friction effects by the direct application of control theory with improved friction compensation. Analyzing physical phenomena on micro-relieved surfaces through SEM methods, the obtained data about surface characteristics helps synthesize a corresponding control law for the laser positioner and conduct its stability analysis. This work considers a patented laser scanning system incorporating a laser positioning mechanism with inherent friction. SEM micrograph analysis of the friction zone was conducted to compare microscopic imperfections of steel surfaces, which helped infer the dynamics of an internal variable ‘z’ in the friction model and determine a reference value for control synthesis. A nonlinear control algorithm was proposed to compensate for friction to enhance positioning accuracy. The global asymptotic stability of the system was proven using Lyapunov’s direct method and Barbalat’s lemma. Experimental implementation on an STM32 board demonstrated a significant reduction in the uncertainty associated with sensing 3D coordinates using the friction-compensated laser scanning system.</div></div>","PeriodicalId":49842,"journal":{"name":"Mechatronics","volume":"110 ","pages":"Article 103382"},"PeriodicalIF":3.1,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-10DOI: 10.1016/j.mechatronics.2025.103379
Duc-An Nguyen , Diego Dominguez , Khanh T.P. Nguyen , Marcos Orchard , Kamal Medjaher
The development of explainable health indicators (HIs) for multi-component mechatronic systems is vital for monitoring their performance, ensuring their reliability, and optimizing their operational efficiency across a wide range of industries. These indicators play a pivotal role in detecting and diagnosing faults, assessing system health, and guiding maintenance decisions. However, achieving explainability in HIs poses significant challenges, including the selection of the most relevant sensors, the accurate modeling of degradation trends influenced by maintenance activities, and the integration of component dynamics into a system-level representation. To address these challenges, we propose a novel methodology for constructing hierarchical HIs — a two-level structure where component-level degradation signals are first modeled individually, then systematically aggregated to form a comprehensive system-level health representation. The proposed approach, named TRSAE, incorporates an automated sensor selection process to identify the most important sensors, reducing redundancy while improving interpretability. Furthermore, maintenance and downtime effects are explicitly integrated into the modeling process to ensure a more realistic and reliable assessment of system health. By tackling these challenges, our methodology improves transparency in system behavior, strengthens diagnostic capabilities, and builds trust in predictive maintenance decisions. The proposed methodology is validated through a case study in an iron mining system, an environment characterized by extreme operating conditions and continuous heavy loads that accelerate the degradation of critical components. The case study demonstrates how hierarchical HIs can capture complex degradation dynamics, optimize sensor usage, and improve remaining useful life (RUL) predictions, offering actionable insights for proactive maintenance planning and reliable system operation.
{"title":"Construction of hierarchical health indicators for explainable monitoring in multi-component mechatronic systems","authors":"Duc-An Nguyen , Diego Dominguez , Khanh T.P. Nguyen , Marcos Orchard , Kamal Medjaher","doi":"10.1016/j.mechatronics.2025.103379","DOIUrl":"10.1016/j.mechatronics.2025.103379","url":null,"abstract":"<div><div>The development of explainable health indicators (HIs) for multi-component mechatronic systems is vital for monitoring their performance, ensuring their reliability, and optimizing their operational efficiency across a wide range of industries. These indicators play a pivotal role in detecting and diagnosing faults, assessing system health, and guiding maintenance decisions. However, achieving explainability in HIs poses significant challenges, including the selection of the most relevant sensors, the accurate modeling of degradation trends influenced by maintenance activities, and the integration of component dynamics into a system-level representation. To address these challenges, we propose a novel methodology for constructing hierarchical HIs — a two-level structure where component-level degradation signals are first modeled individually, then systematically aggregated to form a comprehensive system-level health representation. The proposed approach, named TRSAE, incorporates an automated sensor selection process to identify the most important sensors, reducing redundancy while improving interpretability. Furthermore, maintenance and downtime effects are explicitly integrated into the modeling process to ensure a more realistic and reliable assessment of system health. By tackling these challenges, our methodology improves transparency in system behavior, strengthens diagnostic capabilities, and builds trust in predictive maintenance decisions. The proposed methodology is validated through a case study in an iron mining system, an environment characterized by extreme operating conditions and continuous heavy loads that accelerate the degradation of critical components. The case study demonstrates how hierarchical HIs can capture complex degradation dynamics, optimize sensor usage, and improve remaining useful life (RUL) predictions, offering actionable insights for proactive maintenance planning and reliable system operation.</div></div>","PeriodicalId":49842,"journal":{"name":"Mechatronics","volume":"110 ","pages":"Article 103379"},"PeriodicalIF":3.1,"publicationDate":"2025-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144588653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-08DOI: 10.1016/j.mechatronics.2025.103380
Mingjie Dong , Shuaibang Wang , Shiping Zuo , Zugan Du , Wenjie Liu , Jianfeng Li
Limb disabilities caused by stroke can severely impact activities of daily living (ADLs), and upper limb rehabilitation training plays a crucial role in promoting the recovery of motor functions. Currently, the studies of upper limb rehabilitation robots have several drawbacks, such as bulkiness, high costs, and the lack of integrated rehabilitation performance evaluation. This study, building on the previously proposed upper limb end-effector bilateral rehabilitation robotic system (EBReRS), derives its forward and inverse kinematics, calculates the Jacobian matrix, plots singularity analysis and performance atlases, and optimizes link dimensions to enhance operational performance, enabling it to carry out rehabilitation tasks more effectively. Based on surface electromyography (sEMG) signals, muscle activation levels were obtained. Utilizing the evaluation data, customized muscle training was introduced by establishing a mapping between muscles and training modes. Experimental results indicate that correct mode mapping during training can enhance muscle activation levels by a factor of 1 to 5. In the future, EBReRS is expected to be utilized for more widespread home rehabilitation, and the proposed rehabilitation evaluation strategy has the potential to be applied to other rehabilitation robots.
{"title":"Kinematic optimal design and rehabilitation performance evaluation of an upper-limb bilateral end-effector mechanism","authors":"Mingjie Dong , Shuaibang Wang , Shiping Zuo , Zugan Du , Wenjie Liu , Jianfeng Li","doi":"10.1016/j.mechatronics.2025.103380","DOIUrl":"10.1016/j.mechatronics.2025.103380","url":null,"abstract":"<div><div>Limb disabilities caused by stroke can severely impact activities of daily living (ADLs), and upper limb rehabilitation training plays a crucial role in promoting the recovery of motor functions. Currently, the studies of upper limb rehabilitation robots have several drawbacks, such as bulkiness, high costs, and the lack of integrated rehabilitation performance evaluation. This study, building on the previously proposed upper limb end-effector bilateral rehabilitation robotic system (EBReRS), derives its forward and inverse kinematics, calculates the Jacobian matrix, plots singularity analysis and performance atlases, and optimizes link dimensions to enhance operational performance, enabling it to carry out rehabilitation tasks more effectively. Based on surface electromyography (sEMG) signals, muscle activation levels were obtained. Utilizing the evaluation data, customized muscle training was introduced by establishing a mapping between muscles and training modes. Experimental results indicate that correct mode mapping during training can enhance muscle activation levels by a factor of 1 to 5. In the future, EBReRS is expected to be utilized for more widespread home rehabilitation, and the proposed rehabilitation evaluation strategy has the potential to be applied to other rehabilitation robots.</div></div>","PeriodicalId":49842,"journal":{"name":"Mechatronics","volume":"110 ","pages":"Article 103380"},"PeriodicalIF":3.1,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144571234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-05DOI: 10.1016/j.mechatronics.2025.103384
Xing Yang, Boyang Zhang, Defa Wu, Yinshui Liu
Water hydraulic high-speed on-off valves (WHSVs) are crucial for managing fluid flow in water hydraulic manipulator systems. As the ambient pressure changes, the dynamic characteristics of WHSVs are affected, which reduces the overall control accuracy of the manipulator. To simultaneously achieve rapid switching and maintain consistent dynamic behavior of WHSVs under variable ambient pressure, a pressure-adaptive multistage voltage and sliding mode control (PMVS) algorithm is proposed. A sliding mode controller is utilized to precisely regulate the coil current at the pre-opening and holding current levels, significantly shortening the switching time of the WHSV. By optimizing the controller’s operation time and modifying the duty cycle of the excitation voltage, the switching time remains stable across different pressures. Based on the structure of the designed WHSV group, an innovative method combining a pressure sensor and a vibration sensor is proposed to capture the dynamic characteristics of the WHSV. Experimental validation demonstrates that the PMVS method efficiently controls the switching delay and regulates the excitation voltage. Dynamic characteristic tests of WHSVs under different pressures are conducted. The results show that PMVS effectively reduces the switching time of WHSVs. Comparative tests reveal that WHSVs driven by PMVS achieve an 86.3 % reduction in opening time and an 87.5 % reduction in closing time compared to conventional pulse width modulation (CPWM). Furthermore, PMVS ensures consistent dynamic characteristics within an ambient pressure range of 0 to 20 MPa, with an opening time deviation of 7.94 % and a closing time deviation of 3.03 %. The PMVS algorithm enables the WHSV to rapidly switch and preserve dynamic characteristics under variable ambient pressures.
{"title":"Fast switching and dynamic characteristics preservation of water hydraulic high-speed on-off valve using pressure-adaptive multistage voltage and sliding mode control","authors":"Xing Yang, Boyang Zhang, Defa Wu, Yinshui Liu","doi":"10.1016/j.mechatronics.2025.103384","DOIUrl":"10.1016/j.mechatronics.2025.103384","url":null,"abstract":"<div><div>Water hydraulic high-speed on-off valves (WHSVs) are crucial for managing fluid flow in water hydraulic manipulator systems. As the ambient pressure changes, the dynamic characteristics of WHSVs are affected, which reduces the overall control accuracy of the manipulator. To simultaneously achieve rapid switching and maintain consistent dynamic behavior of WHSVs under variable ambient pressure, a pressure-adaptive multistage voltage and sliding mode control (PMVS) algorithm is proposed. A sliding mode controller is utilized to precisely regulate the coil current at the pre-opening and holding current levels, significantly shortening the switching time of the WHSV. By optimizing the controller’s operation time and modifying the duty cycle of the excitation voltage, the switching time remains stable across different pressures. Based on the structure of the designed WHSV group, an innovative method combining a pressure sensor and a vibration sensor is proposed to capture the dynamic characteristics of the WHSV. Experimental validation demonstrates that the PMVS method efficiently controls the switching delay and regulates the excitation voltage. Dynamic characteristic tests of WHSVs under different pressures are conducted. The results show that PMVS effectively reduces the switching time of WHSVs. Comparative tests reveal that WHSVs driven by PMVS achieve an 86.3 % reduction in opening time and an 87.5 % reduction in closing time compared to conventional pulse width modulation (CPWM). Furthermore, PMVS ensures consistent dynamic characteristics within an ambient pressure range of 0 to 20 MPa, with an opening time deviation of 7.94 % and a closing time deviation of 3.03 %. The PMVS algorithm enables the WHSV to rapidly switch and preserve dynamic characteristics under variable ambient pressures.</div></div>","PeriodicalId":49842,"journal":{"name":"Mechatronics","volume":"110 ","pages":"Article 103384"},"PeriodicalIF":3.1,"publicationDate":"2025-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144563671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-26DOI: 10.1016/j.mechatronics.2025.103364
Yongchao Wang , Tian Zheng , Maged Iskandar , Marion Leibold , Jinoh Lee
This article proposes an optimization-based method for robust yet efficient control of flexible-joint robots by using the model predictive control approach. The time-delay estimation (TDE) technique is used to approximate uncertain and nonlinear dynamic equations, where neither concrete knowledge of mathematical system model parameters is required in the approximation, thus granting the model-free property for dynamics compensation and real-time system linearization. TDE is integrated with model predictive control, which is designated as the incremental model predictive control (IMPC) framework. This approach guarantees the tracking performance of the flexible joint robot with input and output constraints, such as motor torque and joint states. Moreover, the proposed controller can practically circumvent high-order derivatives in implementation while providing robust tracking, a capability that conventional methods for flexible joint robots often face challenges due to the inherent nature of their high-order dynamics. The input-to-state stability of IMPC in a local region around the reachable reference trajectory is theoretically proven, and the high approximation accuracy of the resulting incremental system is analyzed. Finally, a series of experiments is conducted on a flexible-joint robot to verify the practical effectiveness of IMPC, and superior performance in terms of high accuracy, high computational efficiency, and constraint admissibility is demonstrated.
{"title":"Practical and robust incremental model predictive control for flexible-joint robots","authors":"Yongchao Wang , Tian Zheng , Maged Iskandar , Marion Leibold , Jinoh Lee","doi":"10.1016/j.mechatronics.2025.103364","DOIUrl":"10.1016/j.mechatronics.2025.103364","url":null,"abstract":"<div><div>This article proposes an optimization-based method for robust yet efficient control of flexible-joint robots by using the model predictive control approach. The time-delay estimation (TDE) technique is used to approximate uncertain and nonlinear dynamic equations, where neither concrete knowledge of mathematical system model parameters is required in the approximation, thus granting the model-free property for dynamics compensation and real-time system linearization. TDE is integrated with model predictive control, which is designated as the incremental model predictive control (IMPC) framework. This approach guarantees the tracking performance of the flexible joint robot with input and output constraints, such as motor torque and joint states. Moreover, the proposed controller can practically circumvent high-order derivatives in implementation while providing robust tracking, a capability that conventional methods for flexible joint robots often face challenges due to the inherent nature of their high-order dynamics. The input-to-state stability of IMPC in a local region around the reachable reference trajectory is theoretically proven, and the high approximation accuracy of the resulting incremental system is analyzed. Finally, a series of experiments is conducted on a flexible-joint robot to verify the practical effectiveness of IMPC, and superior performance in terms of high accuracy, high computational efficiency, and constraint admissibility is demonstrated.</div></div>","PeriodicalId":49842,"journal":{"name":"Mechatronics","volume":"110 ","pages":"Article 103364"},"PeriodicalIF":3.1,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144481057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-25DOI: 10.1016/j.mechatronics.2025.103378
Kaixian Ba , Ning Liu , Jinbo She , Yuan Wang , Guoliang Ma , Bin Yu , Xiangdong Kong
Accurate position regulation in hydraulic servo systems (HDU) plays a critical role in ensuring system stability, operational efficiency, and achieving high-accuracy performance. However, friction-induced nonlinearities, including Stribeck effects and internal friction dynamics, significantly impact tracking accuracy. This paper introduces a matrix-sensitivity-based active disturbance rejection control (MSADRC) method that compensates for friction without requiring an explicit friction model. By leveraging matrix sensitivity, MSADRC effectively decouples system dynamics and enhances control accuracy, particularly in suppressing frictional effects. A third-order extended state observer (ESO) first estimates total system disturbances, while a model predictive mechanism converts nonlinear time-varying disturbances into a feedforward compensation term. The resulting matrix sensitivity-based compensation optimally adjusts system response, ensuring improved performance. Experimental results show that MSADRC effectively mitigates nonlinear disturbances, reducing peak error by up to 55 % compared to conventional ADRC methods. This approach provides a reliable and efficient strategy to address adaptive friction compensation issues in hydraulic control systems.
{"title":"Matrix-sensitivity-based active disturbance rejection control for hydraulic servo positioning systems with friction compensation","authors":"Kaixian Ba , Ning Liu , Jinbo She , Yuan Wang , Guoliang Ma , Bin Yu , Xiangdong Kong","doi":"10.1016/j.mechatronics.2025.103378","DOIUrl":"10.1016/j.mechatronics.2025.103378","url":null,"abstract":"<div><div>Accurate position regulation in hydraulic servo systems (HDU) plays a critical role in ensuring system stability, operational efficiency, and achieving high-accuracy performance. However, friction-induced nonlinearities, including Stribeck effects and internal friction dynamics, significantly impact tracking accuracy. This paper introduces a matrix-sensitivity-based active disturbance rejection control (MSADRC) method that compensates for friction without requiring an explicit friction model. By leveraging matrix sensitivity, MSADRC effectively decouples system dynamics and enhances control accuracy, particularly in suppressing frictional effects. A third-order extended state observer (ESO) first estimates total system disturbances, while a model predictive mechanism converts nonlinear time-varying disturbances into a feedforward compensation term. The resulting matrix sensitivity-based compensation optimally adjusts system response, ensuring improved performance. Experimental results show that MSADRC effectively mitigates nonlinear disturbances, reducing peak error by up to 55 % compared to conventional ADRC methods. This approach provides a reliable and efficient strategy to address adaptive friction compensation issues in hydraulic control systems.</div></div>","PeriodicalId":49842,"journal":{"name":"Mechatronics","volume":"110 ","pages":"Article 103378"},"PeriodicalIF":3.1,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144470701","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Growing demands in the semiconductor industry necessitate increasingly stringent requirements on throughput and positioning accuracy of lithographic equipment. Meeting these demands involves employing highly aggressive motion profiles, which introduce position-dependent flexible dynamics, thus compromising achievable position tracking performance. This paper introduces a control approach enabling active compensation of position-dependent flexible dynamics by extending the conventional rigid-body control structure to include active control of flexible dynamics. To facilitate real-time implementation of the control algorithm, appropriate position-dependent weighting functions are introduced, ensuring computationally efficient execution of the proposed approach. The efficacy of the proposed control design approach is demonstrated through experiments conducted on a state-of-the-art extreme ultraviolet (EUV) wafer stage.
{"title":"Active compensation of position dependent flexible dynamics in high-precision mechatronics","authors":"Yorick Broens , Hans Butler , Ramidin Kamidi , Koen Verkerk , Siep Weiland","doi":"10.1016/j.mechatronics.2025.103377","DOIUrl":"10.1016/j.mechatronics.2025.103377","url":null,"abstract":"<div><div>Growing demands in the semiconductor industry necessitate increasingly stringent requirements on throughput and positioning accuracy of lithographic equipment. Meeting these demands involves employing highly aggressive motion profiles, which introduce position-dependent flexible dynamics, thus compromising achievable position tracking performance. This paper introduces a control approach enabling active compensation of position-dependent flexible dynamics by extending the conventional rigid-body control structure to include active control of flexible dynamics. To facilitate real-time implementation of the control algorithm, appropriate position-dependent weighting functions are introduced, ensuring computationally efficient execution of the proposed approach. The efficacy of the proposed control design approach is demonstrated through experiments conducted on a state-of-the-art extreme ultraviolet (EUV) wafer stage.</div></div>","PeriodicalId":49842,"journal":{"name":"Mechatronics","volume":"110 ","pages":"Article 103377"},"PeriodicalIF":3.1,"publicationDate":"2025-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144470703","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-24DOI: 10.1016/j.mechatronics.2025.103374
Andrea Ruo, Luca Bernardi, Ludovico Campanelli, Mattia Grespan, Danila Trane, Roberto Sedoni, Diego Angeli, Lorenzo Sabattini, Valeria Villani
Grasping, carrying, and placing objects are fundamental capabilities and common operations for robots and robotic manipulators. To ensure secure grasping of objects with a wide variety of shapes, sizes, and materials, various sensors and control strategies are also necessary. In this paper, an electromagnetic robotic gripper is proposed. The exploitation of electromagnetism principles for grasping is not new in the literature, but the proposed design innovation aims at proposing an open-source and low-cost solution that can be 3D printed. The developed prototype was tested by performing pick and place operations on samples of progressively increasing mass. Finally, a thermodynamic analysis was conducted to determine the steady-state external temperature of the shell and identify its limitations.
{"title":"A low-cost 3D printed electromagnetic gripper for robotic arms","authors":"Andrea Ruo, Luca Bernardi, Ludovico Campanelli, Mattia Grespan, Danila Trane, Roberto Sedoni, Diego Angeli, Lorenzo Sabattini, Valeria Villani","doi":"10.1016/j.mechatronics.2025.103374","DOIUrl":"10.1016/j.mechatronics.2025.103374","url":null,"abstract":"<div><div>Grasping, carrying, and placing objects are fundamental capabilities and common operations for robots and robotic manipulators. To ensure secure grasping of objects with a wide variety of shapes, sizes, and materials, various sensors and control strategies are also necessary. In this paper, an electromagnetic robotic gripper is proposed. The exploitation of electromagnetism principles for grasping is not new in the literature, but the proposed design innovation aims at proposing an open-source and low-cost solution that can be 3D printed. The developed prototype was tested by performing pick and place operations on samples of progressively increasing mass. Finally, a thermodynamic analysis was conducted to determine the steady-state external temperature of the shell and identify its limitations.</div></div>","PeriodicalId":49842,"journal":{"name":"Mechatronics","volume":"110 ","pages":"Article 103374"},"PeriodicalIF":3.1,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144366176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Reliable detection and segmentation of human hands are critical for enhancing safety and facilitating advanced interactions in human–robot collaboration. Current research predominantly evaluates hand segmentation under in-distribution (ID) data, which reflects the training data of deep learning (DL) models. However, this approach fails to address out-of-distribution (OOD) scenarios that often arise in real-world human–robot interactions. In this work, we make three key contributions: first we assess the generalization of deep learning (DL) models for hand segmentation under both ID and OOD scenarios, utilizing a newly collected industrial dataset that captures a wide range of real-world conditions including simple and cluttered backgrounds with industrial tools, varying numbers of hands (0 to 4), gloves, rare gestures, and motion blur. Our second contribution is considering both egocentric and static viewpoints. We evaluated the models trained on four datasets, i.e. EgoHands, Ego2Hands (egocentric mobile camera), HADR, and HAGS (static fixed viewpoint) by testing them with both egocentric (head-mounted) and static cameras, enabling robustness evaluation from multiple points of view. Our third contribution is introducing an uncertainty analysis pipeline based on the predictive entropy of predicted hand pixels. This procedure enables flagging unreliable segmentation outputs by applying thresholds established in the validation phase. This enables automatic identification and filtering of untrustworthy predictions, significantly improving segmentation reliability in OOD scenarios. For segmentation, we used a deep ensemble model composed of UNet and RefineNet as base learners. Our experiments demonstrate that models trained on industrial datasets (HADR, HAGS) outperform those trained on non-industrial datasets, both in segmentation accuracy and in their ability to flag unreliable outputs via uncertainty estimation. These findings underscore the necessity of domain-specific training data and show that our uncertainty analysis pipeline can provide a practical safety layer for real-world deployment.
{"title":"Testing human-hand segmentation on in-distribution and out-of-distribution data in human–robot interactions using a deep ensemble model","authors":"Reza Jalayer , Yuxin Chen , Masoud Jalayer , Carlotta Orsenigo , Masayoshi Tomizuka","doi":"10.1016/j.mechatronics.2025.103365","DOIUrl":"10.1016/j.mechatronics.2025.103365","url":null,"abstract":"<div><div>Reliable detection and segmentation of human hands are critical for enhancing safety and facilitating advanced interactions in human–robot collaboration. Current research predominantly evaluates hand segmentation under in-distribution (ID) data, which reflects the training data of deep learning (DL) models. However, this approach fails to address out-of-distribution (OOD) scenarios that often arise in real-world human–robot interactions. In this work, we make three key contributions: first we assess the generalization of deep learning (DL) models for hand segmentation under both ID and OOD scenarios, utilizing a newly collected industrial dataset that captures a wide range of real-world conditions including simple and cluttered backgrounds with industrial tools, varying numbers of hands (0 to 4), gloves, rare gestures, and motion blur. Our second contribution is considering both egocentric and static viewpoints. We evaluated the models trained on four datasets, i.e. EgoHands, Ego2Hands (egocentric mobile camera), HADR, and HAGS (static fixed viewpoint) by testing them with both egocentric (head-mounted) and static cameras, enabling robustness evaluation from multiple points of view. Our third contribution is introducing an uncertainty analysis pipeline based on the predictive entropy of predicted hand pixels. This procedure enables flagging unreliable segmentation outputs by applying thresholds established in the validation phase. This enables automatic identification and filtering of untrustworthy predictions, significantly improving segmentation reliability in OOD scenarios. For segmentation, we used a deep ensemble model composed of UNet and RefineNet as base learners. Our experiments demonstrate that models trained on industrial datasets (HADR, HAGS) outperform those trained on non-industrial datasets, both in segmentation accuracy and in their ability to flag unreliable outputs via uncertainty estimation. These findings underscore the necessity of domain-specific training data and show that our uncertainty analysis pipeline can provide a practical safety layer for real-world deployment.</div></div>","PeriodicalId":49842,"journal":{"name":"Mechatronics","volume":"110 ","pages":"Article 103365"},"PeriodicalIF":3.1,"publicationDate":"2025-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144329530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-20DOI: 10.1016/j.mechatronics.2025.103366
Mirado Rajaomarosata, Luc Jaulin, Lionel Lapierre, Simon Rohou
Bio-inspired robots remain far less energy-efficient than animals because conventional controllers impose trajectories that fight passive dynamics, whereas animals exploit resonance through natural nonlinear normal modes (NNM), whose periodic internal motions form a smooth 2D invariant surface; We ask how to define and compute the natural motions of a conservative locomotion system: propulsion arises only from no-slip constraints, and once initiated, a gait persists without actuation—like a frictionless pendulum. We tackle non-holonomic constraints on the Pendrivencar, a vehicle driven by a motorised pendulum with a cubic torsional spring; We introduce the Nonholonomic Locomotion - NNM (NL-NNM): extract a high-speed spectral seed – where chassis oscillations vanish and the pendulum is neutrally stable – refine the periodic orbit, and continue the resulting 2D invariant manifold via pseudo-arclength across three slow centre manifolds (stable for positive speed, neutral at zero, unstable for negative) from non-isolated rectilinear equilibria; We demonstrate the first NL-NNM for a moving non-holonomic robot: internal orbits produce a pendulum–chassis choreography whose energy-dependent frequency shifts and harmonic richness exceed linear predictions. Via geometric phase, each orbit yields undulatory straight-line motion. A dual-loop control simulation confirms autonomous path tracking with only the pendulum; Extending to dissipative regimes via non-linear resonant modes offers a path to high-efficiency locomotion in aquatic, aerial, legged, soft-bodied, and other robots.
{"title":"Natural efficient gaits from Nonholonomic Locomotion Nonlinear Normal Mode (NL-NNM): The Pendrivencar case","authors":"Mirado Rajaomarosata, Luc Jaulin, Lionel Lapierre, Simon Rohou","doi":"10.1016/j.mechatronics.2025.103366","DOIUrl":"10.1016/j.mechatronics.2025.103366","url":null,"abstract":"<div><div>Bio-inspired robots remain far less energy-efficient than animals because conventional controllers impose trajectories that fight passive dynamics, whereas animals exploit resonance through <em>natural nonlinear normal modes (NNM)</em>, whose periodic internal motions form a smooth 2D invariant surface; We ask how to define and compute the <em>natural motions of a conservative locomotion system</em>: propulsion arises only from <em>no-slip constraints</em>, and once initiated, a gait persists without actuation—like a frictionless pendulum. We tackle non-holonomic constraints on the <em>Pendrivencar</em>, a vehicle driven by a <em>motorised pendulum with a cubic torsional spring</em>; We introduce the <strong>Nonholonomic Locomotion - NNM (NL-NNM)</strong>: extract a <em>high-speed spectral seed</em> – where chassis oscillations vanish and the pendulum is neutrally stable – refine the periodic orbit, and continue the resulting <em>2D invariant manifold</em> via pseudo-arclength across <em>three slow centre manifolds</em> (stable for positive speed, neutral at zero, unstable for negative) from non-isolated rectilinear equilibria; We demonstrate the first NL-NNM for a moving non-holonomic robot: internal orbits produce a <em>pendulum–chassis choreography</em> whose <em>energy-dependent frequency shifts</em> and <em>harmonic richness</em> exceed linear predictions. Via <em>geometric phase</em>, each orbit yields undulatory straight-line motion. A <em>dual-loop control simulation</em> confirms autonomous path tracking with only the pendulum; Extending to dissipative regimes via <em>non-linear resonant modes</em> offers a path to high-efficiency locomotion in aquatic, aerial, legged, soft-bodied, and other robots.</div></div>","PeriodicalId":49842,"journal":{"name":"Mechatronics","volume":"110 ","pages":"Article 103366"},"PeriodicalIF":3.1,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144322976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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