Pub Date : 2025-10-01Epub 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":"2025-10-01","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 : 2025-10-01Epub 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":"2025-10-01","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}
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":"2025-10-01","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 : 2025-10-01Epub Date: 2025-07-31DOI: 10.1016/j.mechatronics.2025.103385
Quentin Brateau, Loïck Degorre, Fabrice Le Bars, Luc Jaulin
Navigating Autonomous Underwater Vehicles (AUVs) presents significant challenges due to the absence of traditional localization systems. Cycle navigation emerges as a promising paradigm, enabling reliable navigation using minimal exteroceptive measurements. This approach leverages predefined cyclic trajectories, which are stabilized based on environmental feedback, ensuring frugal and discreet operations without reliance on high computational power or extensive sensor systems. This work aims to prove the stability of the cycle navigation. As cycle navigation is a non-linear system governed by a discrete inclusion condition, conventional methods have trouble to prove its stability. For this reason, this paper focuses on set methods to prove the stability of cycle navigation. The stability is proven by exhibiting a positive invariant set, which is a set stable by application of the evolution function of the system. This ensures that the evolution function will not remove states from the positively invariant set. Then, the characterization of the capture basin is an asset when performing cycle navigation, as it represents the set of initial states for the system which leads to the positive invariant set. Once the system reaches either the capture basin or the positive invariant set, which are generalized as a capture set, it remains captured forever. This approach not only guarantees the stability of the system in the neighborhood of the equilibrium point, but also establishes that it exists an area in which the stability of the cycle navigation will lead to a stable behavior. This work offers a robust, computationally efficient alternative to traditional stability methods, particularly suited for resource-constrained AUVs, because the underwater environment lacks suitable, cheap and easy-to-use localization methods, which forces us finding alternative ways to navigate and explore this particular environment.
{"title":"Proving the stability of cycle navigation using capture sets","authors":"Quentin Brateau, Loïck Degorre, Fabrice Le Bars, Luc Jaulin","doi":"10.1016/j.mechatronics.2025.103385","DOIUrl":"10.1016/j.mechatronics.2025.103385","url":null,"abstract":"<div><div>Navigating Autonomous Underwater Vehicles (AUVs) presents significant challenges due to the absence of traditional localization systems. Cycle navigation emerges as a promising paradigm, enabling reliable navigation using minimal exteroceptive measurements. This approach leverages predefined cyclic trajectories, which are stabilized based on environmental feedback, ensuring frugal and discreet operations without reliance on high computational power or extensive sensor systems. This work aims to prove the stability of the cycle navigation. As cycle navigation is a non-linear system governed by a discrete inclusion condition, conventional methods have trouble to prove its stability. For this reason, this paper focuses on set methods to prove the stability of cycle navigation. The stability is proven by exhibiting a positive invariant set, which is a set stable by application of the evolution function of the system. This ensures that the evolution function will not remove states from the positively invariant set. Then, the characterization of the capture basin is an asset when performing cycle navigation, as it represents the set of initial states for the system which leads to the positive invariant set. Once the system reaches either the capture basin or the positive invariant set, which are generalized as a capture set, it remains captured forever. This approach not only guarantees the stability of the system in the neighborhood of the equilibrium point, but also establishes that it exists an area in which the stability of the cycle navigation will lead to a stable behavior. This work offers a robust, computationally efficient alternative to traditional stability methods, particularly suited for resource-constrained AUVs, because the underwater environment lacks suitable, cheap and easy-to-use localization methods, which forces us finding alternative ways to navigate and explore this particular environment.</div></div>","PeriodicalId":49842,"journal":{"name":"Mechatronics","volume":"110 ","pages":"Article 103385"},"PeriodicalIF":3.1,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144739056","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":"2025-10-01","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}
Distributed drive electric vehicles actuated by in-wheel motors and brake-by-wire systems enable tracking target motion while improving extra vehicle performance. Outboard brake torque allocated on front and rear wheels generates diverse vertically reactive anti-dive forces, providing an innovative approach to mitigate brake dive without requiring active suspensions. However, the differing dynamics of regenerative and hydraulic braking, along with multiple uncertain vehicle parameters, pose significant challenges to achieving robustness under mixed uncertainties. Moreover, pitch-induced bias in onboard acceleration measurements further degrades control accuracy. To address above problems, this paper proposes a robust, comfort-enhanced longitudinal control system with coordinated braking. A three-degree-of-freedom vehicle dynamics model is developed to incorporate the effect of anti-dive forces. For accurate feedback, a robust observer is designed to compensate pitch-variation-related acceleration measurement biases. By integrating dynamic and parametric uncertainties into the control-oriented model, the mixed -synthesis is employed to design a two-degree-of-freedom controller to robustly optimize the acceleration tracking and anti-dive performance. Compared to the controller designed by standard -synthesis, the proposed approach achieves a 10% improvement in robust performance. Real-vehicle experiments validate the system’s effectiveness, demonstrating over a 27% reduction in pitch angle while maintaining satisfactory acceleration responses under blended braking conditions.
{"title":"Comfort-enhanced longitudinal control for DDEVs: A robust brake coordination approach leveraging reactive anti-dive forces","authors":"Yanjun Ren , Tong Shen , Mingzhuo Zhao , Fanxun Wang , Liwei Xu , Guodong Yin","doi":"10.1016/j.mechatronics.2025.103357","DOIUrl":"10.1016/j.mechatronics.2025.103357","url":null,"abstract":"<div><div>Distributed drive electric vehicles actuated by in-wheel motors and brake-by-wire systems enable tracking target motion while improving extra vehicle performance. Outboard brake torque allocated on front and rear wheels generates diverse vertically reactive anti-dive forces, providing an innovative approach to mitigate brake dive without requiring active suspensions. However, the differing dynamics of regenerative and hydraulic braking, along with multiple uncertain vehicle parameters, pose significant challenges to achieving robustness under mixed uncertainties. Moreover, pitch-induced bias in onboard acceleration measurements further degrades control accuracy. To address above problems, this paper proposes a robust, comfort-enhanced longitudinal control system with coordinated braking. A three-degree-of-freedom vehicle dynamics model is developed to incorporate the effect of anti-dive forces. For accurate feedback, a robust <span><math><mrow><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>/</mo><msub><mrow><mi>H</mi></mrow><mrow><mi>∞</mi></mrow></msub></mrow></math></span> observer is designed to compensate pitch-variation-related acceleration measurement biases. By integrating dynamic and parametric uncertainties into the control-oriented model, the mixed <span><math><mi>μ</mi></math></span>-synthesis is employed to design a two-degree-of-freedom controller to robustly optimize the acceleration tracking and anti-dive performance. Compared to the controller designed by standard <span><math><mi>μ</mi></math></span>-synthesis, the proposed approach achieves a 10% improvement in robust performance. Real-vehicle experiments validate the system’s effectiveness, demonstrating over a 27% reduction in pitch angle while maintaining satisfactory acceleration responses under blended braking conditions.</div></div>","PeriodicalId":49842,"journal":{"name":"Mechatronics","volume":"110 ","pages":"Article 103357"},"PeriodicalIF":3.1,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144281075","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 : 2025-10-01Epub Date: 2025-06-19DOI: 10.1016/j.mechatronics.2025.103359
G. Wang , R. Chalard , J.A. Cifuentes , M.T. Pham
Pneumatic Artificial Muscles (PAMs) are highly nonlinear actuators widely used in robotics, rehabilitation, and other dynamic applications. Their complex behavior poses significant challenges for traditional system identification methods. Although machine learning techniques have shown remarkable success in modeling nonlinear systems, their black-box nature often leads to interpretability issues and susceptibility to overfitting. This study proposes a novel hybrid modeling approach that combines the strengths of analytical models with neural networks to capture the inverse thermodynamic behavior of PAMs. The results demonstrate that the hybrid model outperformed both analytical and purely neural network models. The obtained models were further used for model-based control design and the results show that the application of hybrid model improved the tracking performance.
{"title":"Learning an inverse thermodynamic model for Pneumatic Artificial Muscles control","authors":"G. Wang , R. Chalard , J.A. Cifuentes , M.T. Pham","doi":"10.1016/j.mechatronics.2025.103359","DOIUrl":"10.1016/j.mechatronics.2025.103359","url":null,"abstract":"<div><div>Pneumatic Artificial Muscles (PAMs) are highly nonlinear actuators widely used in robotics, rehabilitation, and other dynamic applications. Their complex behavior poses significant challenges for traditional system identification methods. Although machine learning techniques have shown remarkable success in modeling nonlinear systems, their black-box nature often leads to interpretability issues and susceptibility to overfitting. This study proposes a novel hybrid modeling approach that combines the strengths of analytical models with neural networks to capture the inverse thermodynamic behavior of PAMs. The results demonstrate that the hybrid model outperformed both analytical and purely neural network models. The obtained models were further used for model-based control design and the results show that the application of hybrid model improved the tracking performance.</div></div>","PeriodicalId":49842,"journal":{"name":"Mechatronics","volume":"110 ","pages":"Article 103359"},"PeriodicalIF":3.1,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144313090","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 : 2025-10-01Epub Date: 2025-08-05DOI: 10.1016/j.mechatronics.2025.103392
Tingze Fang, Christopher T. Freeman
Tremor is a condition that impacts millions of people globally, and is characterised by a periodic limb movement that impedes voluntary motion. Recent studies have shown that functional electrical stimulation (FES) can help reduce tremor by artificially stimulating opposing muscles, thereby decreasing the oscillation’s amplitude. Various control methods have been proposed for this purpose, but repetitive control (RC) has shown the most promise with potential to completely suppress the tremor. While several RC approaches have demonstrated suppression rates of up to 90%, they heavily rely on an accurate model of the underlying dynamics, and their effectiveness declines steeply due to factors like muscle fatigue, spasticity, and modelling inaccuracies.
This paper introduces a multiple model switched repetitive control (MMSRC) framework that addresses the limitations of existing RC approaches. It guarantees high performance tremor suppression provided the true dynamics belong to an uncertainty set specified by the designer. This enables it to adapt to time-varying physiological changes, as well as changes in the placement of the FES electrodes. Moreover, once an uncertainty set has been established, it removes the need for subsequent model identification. This is an important step towards home-based tremor suppression where model identification and expert tuning are not possible. Experimental validation is performed with four participants, showing that MMSRC effectively suppresses tremor even in the presence of severe modelling uncertainty and fatigue, unlike conventional RC methods which often become unstable under these conditions.
{"title":"Multiple model switched repetitive control for tremor suppression","authors":"Tingze Fang, Christopher T. Freeman","doi":"10.1016/j.mechatronics.2025.103392","DOIUrl":"10.1016/j.mechatronics.2025.103392","url":null,"abstract":"<div><div>Tremor is a condition that impacts millions of people globally, and is characterised by a periodic limb movement that impedes voluntary motion. Recent studies have shown that functional electrical stimulation (FES) can help reduce tremor by artificially stimulating opposing muscles, thereby decreasing the oscillation’s amplitude. Various control methods have been proposed for this purpose, but repetitive control (RC) has shown the most promise with potential to completely suppress the tremor. While several RC approaches have demonstrated suppression rates of up to 90%, they heavily rely on an accurate model of the underlying dynamics, and their effectiveness declines steeply due to factors like muscle fatigue, spasticity, and modelling inaccuracies.</div><div>This paper introduces a multiple model switched repetitive control (MMSRC) framework that addresses the limitations of existing RC approaches. It guarantees high performance tremor suppression provided the true dynamics belong to an uncertainty set specified by the designer. This enables it to adapt to time-varying physiological changes, as well as changes in the placement of the FES electrodes. Moreover, once an uncertainty set has been established, it removes the need for subsequent model identification. This is an important step towards home-based tremor suppression where model identification and expert tuning are not possible. Experimental validation is performed with four participants, showing that MMSRC effectively suppresses tremor even in the presence of severe modelling uncertainty and fatigue, unlike conventional RC methods which often become unstable under these conditions.</div></div>","PeriodicalId":49842,"journal":{"name":"Mechatronics","volume":"110 ","pages":"Article 103392"},"PeriodicalIF":3.1,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144770680","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 : 2025-10-01Epub Date: 2025-06-16DOI: 10.1016/j.mechatronics.2025.103363
Yin Sun, Feng Zhao, Zhenjing Guo, Xiaojun Yan
The parallel-suspension type inertially stabilized platform utilizes a unique flexible support structure and non-contact linear actuators to enable simultaneous high-efficiency vibration suppression control of optical payloads across multiple degrees of freedom. Compared to traditional series – gimbals type stabilized platforms, it offers a higher payload-to-weight ratio and rapid response characteristics. In this paper, a 6-degree-of-freedom dynamic model for the parallel-suspension inertially stabilized platform is established, a control method is designed, and an actual engineering prototype is constructed. Specifically, a flexible support element model that accounts for column instability phenomenon is developed. Based on the parallel mount configuration a complete 6-degree-of-freedom dynamic model of the entire platform is constructed. Furthermore, due the variable parameter characteristics of flexible elastic elements, a μ synthesis control method considering the uncertainty of model parameters is designed. The experimental results show that the μ controller can effectively reduce the external sinusoidal angular disturbance to less than 25 % and the linear vibration disturbance to less than 3 % of the original disturbance while maintaining the robustness. Both simulation and experimental results verify the correctness and effectiveness of the proposed model and method.
{"title":"Dynamics modeling and μ synthesis for a parallel - suspension type inertially stabilized platform","authors":"Yin Sun, Feng Zhao, Zhenjing Guo, Xiaojun Yan","doi":"10.1016/j.mechatronics.2025.103363","DOIUrl":"10.1016/j.mechatronics.2025.103363","url":null,"abstract":"<div><div>The parallel-suspension type inertially stabilized platform utilizes a unique flexible support structure and non-contact linear actuators to enable simultaneous high-efficiency vibration suppression control of optical payloads across multiple degrees of freedom. Compared to traditional series – gimbals type stabilized platforms, it offers a higher payload-to-weight ratio and rapid response characteristics. In this paper, a 6-degree-of-freedom dynamic model for the parallel-suspension inertially stabilized platform is established, a control method is designed, and an actual engineering prototype is constructed. Specifically, a flexible support element model that accounts for column instability phenomenon is developed. Based on the parallel mount configuration a complete 6-degree-of-freedom dynamic model of the entire platform is constructed. Furthermore, due the variable parameter characteristics of flexible elastic elements, a <em>μ</em> synthesis control method considering the uncertainty of model parameters is designed. The experimental results show that the <em>μ</em> controller can effectively reduce the external sinusoidal angular disturbance to less than 25 % and the linear vibration disturbance to less than 3 % of the original disturbance while maintaining the robustness. Both simulation and experimental results verify the correctness and effectiveness of the proposed model and method.</div></div>","PeriodicalId":49842,"journal":{"name":"Mechatronics","volume":"110 ","pages":"Article 103363"},"PeriodicalIF":3.1,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144291496","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 : 2025-10-01Epub Date: 2025-07-26DOI: 10.1016/j.mechatronics.2025.103391
Xiaolong Shu , Yifang Zhang , Jianfa Lin , Bingliang Guan , Min Qian , Qiaosheng Pan
In this study, a cross-scale piezoelectric screw motor was proposed, designed, fabricated and tested. The proposed motor can operate in quasi-static and resonant states, and achieves cross-scale motion output through mode conversion. The motor is comprised of a stator and a rotor, with the same internal and external screws. The motor’s motion is achieved by friction between the stator and the rotor. Structure and working principle of the motor are introduced. The vibration modes of the stator in different modes were studied through finite element analysis. The motor's dynamic model was established. Finally, the prototype was fabricated, and the output performance was tested. Experimental results demonstrate a minimum resolution of 12.5 nm and a maximum load capacity of 12 N in quasi-static mode. When operating in resonant state, the motor achieves a maximum speed of 10.4mm/min (32.8 rpm), the maximum load capacity is 30 N and the maximum efficiency is 0.36 % when the prototype is rotated forward. When the motor is reversed, the maximum speed is 20.8 mm/min (65.5 rpm), the load capacity reaches 33 N, and the maximum efficiency is 0.46 %. The proposed piezoelectric motor promotes the development of cross-scale actuators.
{"title":"Development of a type of cross-scale piezoelectric screw motor operating in quasi-static and resonant states","authors":"Xiaolong Shu , Yifang Zhang , Jianfa Lin , Bingliang Guan , Min Qian , Qiaosheng Pan","doi":"10.1016/j.mechatronics.2025.103391","DOIUrl":"10.1016/j.mechatronics.2025.103391","url":null,"abstract":"<div><div>In this study, a cross-scale piezoelectric screw motor was proposed, designed, fabricated and tested. The proposed motor can operate in quasi-static and resonant states, and achieves cross-scale motion output through mode conversion. The motor is comprised of a stator and a rotor, with the same internal and external screws. The motor’s motion is achieved by friction between the stator and the rotor. Structure and working principle of the motor are introduced. The vibration modes of the stator in different modes were studied through finite element analysis. The motor's dynamic model was established. Finally, the prototype was fabricated, and the output performance was tested. Experimental results demonstrate a minimum resolution of 12.5 nm and a maximum load capacity of 12 N in quasi-static mode. When operating in resonant state, the motor achieves a maximum speed of 10.4mm/min (32.8 rpm), the maximum load capacity is 30 N and the maximum efficiency is 0.36 % when the prototype is rotated forward. When the motor is reversed, the maximum speed is 20.8 mm/min (65.5 rpm), the load capacity reaches 33 N, and the maximum efficiency is 0.46 %. The proposed piezoelectric motor promotes the development of cross-scale actuators.</div></div>","PeriodicalId":49842,"journal":{"name":"Mechatronics","volume":"110 ","pages":"Article 103391"},"PeriodicalIF":3.1,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144711347","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号