Mechanism and Machine Theory最新文献

英文中文

An empirical analytical method to determine the human walking ground reaction force at known speeds

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2024-12-30 DOI: 10.1016/j.mechmachtheory.2024.105903

Zehao Hou , Huan Zhao , Wei-Hsin Liao , Chris R. Bowen , Daniel J. Inman , Junyi Cao , Kangqi Fan

The experimental analysis of biomechanical energy harvesting is typically conducted at known speeds. However, the theoretical mapping of walking speed to the ground reaction force is often constrained by the inherent complexity of the energy conservation method commonly applied to solve the spring roller foot model in engineering applications. Consequently, an empirical analytical method has been proposed to address this challenge. This analytical method mathematically models human walking using time-varying spring stiffness. The empirical analytical method is developed based on an empirical gait division ratio of 3:1 and further refined by incorporating the leg swing effect. A comparison between the proposed method and the energy conservation method reveals that the proposed method offers several advantages, including a simple solving process, accurate and unique solutions, and predictions that are independent of prior data. Finally, the proposed empirical analytical method is validated using four distinct datasets, demonstrating its superior capability in predicting ground reaction forces during human walking at known speeds.

{"title":"An empirical analytical method to determine the human walking ground reaction force at known speeds","authors":"Zehao Hou , Huan Zhao , Wei-Hsin Liao , Chris R. Bowen , Daniel J. Inman , Junyi Cao , Kangqi Fan","doi":"10.1016/j.mechmachtheory.2024.105903","DOIUrl":"10.1016/j.mechmachtheory.2024.105903","url":null,"abstract":"<div><div>The experimental analysis of biomechanical energy harvesting is typically conducted at known speeds. However, the theoretical mapping of walking speed to the ground reaction force is often constrained by the inherent complexity of the energy conservation method commonly applied to solve the spring roller foot model in engineering applications. Consequently, an empirical analytical method has been proposed to address this challenge. This analytical method mathematically models human walking using time-varying spring stiffness. The empirical analytical method is developed based on an empirical gait division ratio of 3:1 and further refined by incorporating the leg swing effect. A comparison between the proposed method and the energy conservation method reveals that the proposed method offers several advantages, including a simple solving process, accurate and unique solutions, and predictions that are independent of prior data. Finally, the proposed empirical analytical method is validated using four distinct datasets, demonstrating its superior capability in predicting ground reaction forces during human walking at known speeds.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105903"},"PeriodicalIF":4.5,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Kinematic performance evaluation of a bioinspired 5-DOF parallel driving mechanism with multi-loop coupled chain

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2024-12-27 DOI: 10.1016/j.mechmachtheory.2024.105896

Hanqing Shi , Jinzhu Zhang , Tao Wang , Qingxue Huang

This paper deals with the kinematic performance evaluation of a bioinspired 5-DOF parallel driving mechanism (PDM) PRTU-X5. The PRTU-X5 consists of five open-loop active limbs and one passive hybrid kinematic chain. To tackle the challenge of evaluating the kinematic performance of this 5-DOF PDM with multi-loop coupled kinematic chains, this study presents a divide-and-conquer based evaluation strategy, utilizing the functional sequences and kinematic decoupling to simplify the complex mechanism topology analysis issue into sub-issues of sub-mechanism systems. The local evaluation indices of the sub-mechanisms are derived by integrally utilizing the transmission and interaction performance evaluation criteria. The local comprehensive evaluation index (LCEI) is then defined. Under the guidance of the bionic motion atlas of manual two-arm cooperation, the positioning and orientation capability are evaluated. Finally, the performance maps are plotted to visualize the kinematic performance of the PRTU-X5. The evaluation results show the feasibility and validity of the proposed strategy and indices and provide a foundation for the dimension optimization of the PRTU-X5. This work can serve as a reference for other parallel mechanisms with complex mechanism topology.

{"title":"Kinematic performance evaluation of a bioinspired 5-DOF parallel driving mechanism with multi-loop coupled chain","authors":"Hanqing Shi , Jinzhu Zhang , Tao Wang , Qingxue Huang","doi":"10.1016/j.mechmachtheory.2024.105896","DOIUrl":"10.1016/j.mechmachtheory.2024.105896","url":null,"abstract":"<div><div>This paper deals with the kinematic performance evaluation of a bioinspired 5-DOF parallel driving mechanism (PDM) PRTU-X5. The PRTU-X5 consists of five open-loop active limbs and one passive hybrid kinematic chain. To tackle the challenge of evaluating the kinematic performance of this 5-DOF PDM with multi-loop coupled kinematic chains, this study presents a divide-and-conquer based evaluation strategy, utilizing the functional sequences and kinematic decoupling to simplify the complex mechanism topology analysis issue into sub-issues of sub-mechanism systems. The local evaluation indices of the sub-mechanisms are derived by integrally utilizing the transmission and interaction performance evaluation criteria. The local comprehensive evaluation index (LCEI) is then defined. Under the guidance of the bionic motion atlas of manual two-arm cooperation, the positioning and orientation capability are evaluated. Finally, the performance maps are plotted to visualize the kinematic performance of the PRTU-X5. The evaluation results show the feasibility and validity of the proposed strategy and indices and provide a foundation for the dimension optimization of the PRTU-X5. This work can serve as a reference for other parallel mechanisms with complex mechanism topology.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105896"},"PeriodicalIF":4.5,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The concept of spaces in the structural analysis and synthesis of mechanisms and machines

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2024-12-27 DOI: 10.1016/j.mechmachtheory.2024.105889

Alexander Prikhodko, Anatoly Smelyagin

Mobility analysis is the basic stage in structural synthesis of mechanisms, machines and other mechanical systems. Despite the development of the mechanism and machine theory, the discovery of new structural theories and formulas for determining mobility, many researchers continue to use the traditional Chebyshev formulas for flat mechanisms and Somov-Malyshev for spatial ones, which can lead to incorrect results. In the early 90s of the 20th century, Professor Smelyagin proposed to abandon the artificial division of mechanisms into “planar” (existing in a three-dimensional three-movable space) and “spatial” (existing in a three-dimensional six-movable space) in the structural analysis and synthesis of mechanisms and machines, and to use spaces of different dimensionality and mobility. In this paper, the proposed theory is revealed using practical examples of mechanisms and the spaces in which they exist. Using the concept of a M-movable space, there are derived equations to determine the mobility of simple and complex mechanisms. The examples of the formation of mechanisms in various spaces are given, and also the analysis of their mobility using the developed structural formulas is carried out.

{"title":"The concept of spaces in the structural analysis and synthesis of mechanisms and machines","authors":"Alexander Prikhodko, Anatoly Smelyagin","doi":"10.1016/j.mechmachtheory.2024.105889","DOIUrl":"10.1016/j.mechmachtheory.2024.105889","url":null,"abstract":"<div><div>Mobility analysis is the basic stage in structural synthesis of mechanisms, machines and other mechanical systems. Despite the development of the mechanism and machine theory, the discovery of new structural theories and formulas for determining mobility, many researchers continue to use the traditional Chebyshev formulas for flat mechanisms and Somov-Malyshev for spatial ones, which can lead to incorrect results. In the early 90s of the 20th century, Professor Smelyagin proposed to abandon the artificial division of mechanisms into “planar” (existing in a three-dimensional three-movable space) and “spatial” (existing in a three-dimensional six-movable space) in the structural analysis and synthesis of mechanisms and machines, and to use spaces of different dimensionality and mobility. In this paper, the proposed theory is revealed using practical examples of mechanisms and the spaces in which they exist. Using the concept of a <em>M</em>-movable space, there are derived equations to determine the mobility of simple and complex mechanisms. The examples of the formation of mechanisms in various spaces are given, and also the analysis of their mobility using the developed structural formulas is carried out.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105889"},"PeriodicalIF":4.5,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Two novel indicators for gear crack diagnosis based on vibration responses: Experiment and simulation

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2024-12-27 DOI: 10.1016/j.mechmachtheory.2024.105905

Zeyu Ma , Xiaojian Zhao , Yuping Wu , Hui Ma , Peng Cao , Hong Guan , Zimeng Liu , Caizi Fan , Jiazan Zhu , Pengyu Yan , Zhike Peng

Fatigue crack fault of spur gear is one of the important causes of abnormal vibration and noise in the operation of gear system. Meanwhile, crack fault greatly threatens the operation stability of gear transmission system. To diagnose different crack stages in spur gear transmission systems, experimental studies are conducted to obtain the actual crack propagation paths. Combining with the results of crack growth path obtained by experiment, the dynamic model of spur gear system with crack fault is established considering the process of crack fault evolution in the whole life cycle. The proposed model is verified by comparing the natural frequencies obtained from finite element solid model and experimental results. Based on the simulated vibration responses, two novel indicators for distinguishing the crack propagation stages are proposed. These two indicators have high sensitivity in time domain and frequency domain features. The results are important for fault diagnosis and health monitoring of gear systems.

{"title":"Two novel indicators for gear crack diagnosis based on vibration responses: Experiment and simulation","authors":"Zeyu Ma , Xiaojian Zhao , Yuping Wu , Hui Ma , Peng Cao , Hong Guan , Zimeng Liu , Caizi Fan , Jiazan Zhu , Pengyu Yan , Zhike Peng","doi":"10.1016/j.mechmachtheory.2024.105905","DOIUrl":"10.1016/j.mechmachtheory.2024.105905","url":null,"abstract":"<div><div>Fatigue crack fault of spur gear is one of the important causes of abnormal vibration and noise in the operation of gear system. Meanwhile, crack fault greatly threatens the operation stability of gear transmission system. To diagnose different crack stages in spur gear transmission systems, experimental studies are conducted to obtain the actual crack propagation paths. Combining with the results of crack growth path obtained by experiment, the dynamic model of spur gear system with crack fault is established considering the process of crack fault evolution in the whole life cycle. The proposed model is verified by comparing the natural frequencies obtained from finite element solid model and experimental results. Based on the simulated vibration responses, two novel indicators for distinguishing the crack propagation stages are proposed. These two indicators have high sensitivity in time domain and frequency domain features. The results are important for fault diagnosis and health monitoring of gear systems.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105905"},"PeriodicalIF":4.5,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Elasto-Kinematics and second-order pseudo-rigid model of cross-axis flexure hinges

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2024-12-25 DOI: 10.1016/j.mechmachtheory.2024.105894

Christian Iandiorio, Marco Cirelli, Pietro Salvini , Pier Paolo Valentini

The paper deals with the investigation of the elasto kinematics of the cross-axis flexure hinge and its first- and second-order motion invariants in order to propose an equivalent pseudo-rigid embodiment able to accurately reproduce the relative motion between the connected bodies in a large angle range. Cross-axis flexure hinges are quite common in compliant mechanisms and flexible structures. The main challenge in the study of such flexible links is represented by the statically-indeterminate arrangement that implies the non-trivial deduction of their mechanical response. For this reason, the study is based on the development of an analytical model; this drives the synthesis of a surrogate pseudo-rigid model based on an epicycloidal arrangement requiring a single degree of freedom. The design equations for the general applications are deduced in the paper, in a form ready to use for both analyses and synthesis problems. Both analytical model and pseudo-rigid model have been verified through numerical simulations.

引用次数: 0

An elastodynamic modeling approach based on experimental substructuring for a mobile hybrid robot

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2024-12-24 DOI: 10.1016/j.mechmachtheory.2024.105892

Wei Ma, Haitao Liu, Guofeng Wang, Juliang Xiao

This paper presents an elastodynamic modeling approach based on experimental dynamic substructuring for a mobile hybrid robot that consists of a hybrid machining cell plus an omnidirectional mobile platform. In this method, the frequency response functions (FRFs) of the hybrid machining cell are predicted using the semi-analytical model. Then, the regenerated FRFs of the entire system are constructed using modal testing and parameter identification techniques. Subsequently, the FRFs matrix of the omnidirectional mobile platform is obtained by applying substructure decoupling technology to decouple the former from the latter. Finally, the dynamic model of the entire system is established by assembling the FRFs of the omnidirectional mobile platform and the hybrid machining cell using the substructure coupling technology. The proposed approach solves the problem related to the dynamic response of the hybrid machining cell, which cannot be measured separately by modal testing. The computational results show that the estimated lower-order natural frequencies and the FRFs at the endpoints of the entire system have very good agreement with those obtained by experimental modal testing, which demonstrates the effectiveness of the proposed approach.

{"title":"An elastodynamic modeling approach based on experimental substructuring for a mobile hybrid robot","authors":"Wei Ma, Haitao Liu, Guofeng Wang, Juliang Xiao","doi":"10.1016/j.mechmachtheory.2024.105892","DOIUrl":"10.1016/j.mechmachtheory.2024.105892","url":null,"abstract":"<div><div>This paper presents an elastodynamic modeling approach based on experimental dynamic substructuring for a mobile hybrid robot that consists of a hybrid machining cell plus an omnidirectional mobile platform. In this method, the frequency response functions (FRFs) of the hybrid machining cell are predicted using the semi-analytical model. Then, the regenerated FRFs of the entire system are constructed using modal testing and parameter identification techniques. Subsequently, the FRFs matrix of the omnidirectional mobile platform is obtained by applying substructure decoupling technology to decouple the former from the latter. Finally, the dynamic model of the entire system is established by assembling the FRFs of the omnidirectional mobile platform and the hybrid machining cell using the substructure coupling technology. The proposed approach solves the problem related to the dynamic response of the hybrid machining cell, which cannot be measured separately by modal testing. The computational results show that the estimated lower-order natural frequencies and the FRFs at the endpoints of the entire system have very good agreement with those obtained by experimental modal testing, which demonstrates the effectiveness of the proposed approach.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105892"},"PeriodicalIF":4.5,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Design and investigation of ground micro-gravity experimental system for large space spinning structures

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2024-12-24 DOI: 10.1016/j.mechmachtheory.2024.105891

Guo Wei, Jialiang Sun, Xinyuan Li, Jiaojiao Guo, Dongping Jin

On-orbit dynamic stability of a spacecraft system with a large space structure is affected by external forces and actuator-induced perturbations. To effectively predict the on-orbit dynamic behavior of large space structures, it is urgent to validate them by ground experiments. This paper designs a novel micro-gravity experimental system for simulating the on-orbit operation state of a large space structure and conducting its ground vibration testing research. Firstly, the experimental system uses a spherical air-bearing and a gear-rotating device to achieve frictionless rotational motion of the large space structure. Secondly, two eccentric rotors are employed to simulate an actuator, serving as an on-orbit perturbation source to excite the dynamic characteristics of the large space structure. At the same time, a real-time digital image correlation (DIC) deformation measurement system captures the full-field displacement. Finally, an on-orbit dynamic experiment is conducted on the large space structure in the ground micro-gravity experimental system, and the effectiveness of the experimental system is validated through numerical simulation results.

{"title":"Design and investigation of ground micro-gravity experimental system for large space spinning structures","authors":"Guo Wei, Jialiang Sun, Xinyuan Li, Jiaojiao Guo, Dongping Jin","doi":"10.1016/j.mechmachtheory.2024.105891","DOIUrl":"10.1016/j.mechmachtheory.2024.105891","url":null,"abstract":"<div><div>On-orbit dynamic stability of a spacecraft system with a large space structure is affected by external forces and actuator-induced perturbations. To effectively predict the on-orbit dynamic behavior of large space structures, it is urgent to validate them by ground experiments. This paper designs a novel micro-gravity experimental system for simulating the on-orbit operation state of a large space structure and conducting its ground vibration testing research. Firstly, the experimental system uses a spherical air-bearing and a gear-rotating device to achieve frictionless rotational motion of the large space structure. Secondly, two eccentric rotors are employed to simulate an actuator, serving as an on-orbit perturbation source to excite the dynamic characteristics of the large space structure. At the same time, a real-time digital image correlation (DIC) deformation measurement system captures the full-field displacement. Finally, an on-orbit dynamic experiment is conducted on the large space structure in the ground micro-gravity experimental system, and the effectiveness of the experimental system is validated through numerical simulation results.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105891"},"PeriodicalIF":4.5,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Modeling, optimization, and control of a variable stiffness pneumatic rotary joint with soft-rigid hybrid twisting modules

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2024-12-24 DOI: 10.1016/j.mechmachtheory.2024.105899

Zhujin Jiang , Ketao Zhang

Soft actuators have seen significant advancements in recent years, driven by their potential for adaptive and safe actuation in various applications. However, soft pneumatic actuators may exhibit undesirable deformation, bringing challenges in kinematic modeling and motion control. To address these issues, this paper systematically investigates a soft-rigid hybrid pneumatic rotary joint that integrates two antagonistic twisting modules in series—one performs clockwise helical motion, and another produces anticlockwise helical motion. Theoretical models for the rotary joint's angular displacement, output torque, and stiffness are revealed and verified through simulation and experiments. Experimental results show that the rotary joint can adjust its angular displacement, output torque and stiffness by changing the pressures of two bellows muscles. Additionally, with a classical PID controller, the rotary joint can follow triangle waves with a frequency of 0.5 Hz with a mean absolute error of 3.35° and resist an external disturbance of 1 Nm. The variable stiffness pneumatic rotary joint contains no electronic components, thereby having the potential for applications in electronics-free robots operating in extreme environments, such as nuclear power stations, and explosive gas platforms.

{"title":"Modeling, optimization, and control of a variable stiffness pneumatic rotary joint with soft-rigid hybrid twisting modules","authors":"Zhujin Jiang , Ketao Zhang","doi":"10.1016/j.mechmachtheory.2024.105899","DOIUrl":"10.1016/j.mechmachtheory.2024.105899","url":null,"abstract":"<div><div>Soft actuators have seen significant advancements in recent years, driven by their potential for adaptive and safe actuation in various applications. However, soft pneumatic actuators may exhibit undesirable deformation, bringing challenges in kinematic modeling and motion control. To address these issues, this paper systematically investigates a soft-rigid hybrid pneumatic rotary joint that integrates two antagonistic twisting modules in series—one performs clockwise helical motion, and another produces anticlockwise helical motion. Theoretical models for the rotary joint's angular displacement, output torque, and stiffness are revealed and verified through simulation and experiments. Experimental results show that the rotary joint can adjust its angular displacement, output torque and stiffness by changing the pressures of two bellows muscles. Additionally, with a classical PID controller, the rotary joint can follow triangle waves with a frequency of 0.5 <em>Hz</em> with a mean absolute error of 3.35° and resist an external disturbance of 1 <em>Nm</em>. The variable stiffness pneumatic rotary joint contains no electronic components, thereby having the potential for applications in electronics-free robots operating in extreme environments, such as nuclear power stations, and explosive gas platforms.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105899"},"PeriodicalIF":4.5,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Dynamic characteristics analysis and multi-source disturbances rejection control of a 6-PUS parallel stabilization mechanism on floating base

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2024-12-20 DOI: 10.1016/j.mechmachtheory.2024.105888

Chaoxiong Lin , Baogeng Xin , Shuojie Wang , Songlin Zhou , Weixing Chen , Feng Gao

The safety and efficiency of marine transfers are significantly influenced by the vessel motion under random wave excitations. The conventional ship-mounted stabilization platforms based on the Stewart-Gough platform design face limitations such as inadequate vertical workspace and additional inertial forces. To overcome these challenges, this study introduces a novel parallel stabilization mechanism, with kinematic and dynamic models that incorporate the motion of the floating base and the inertia characteristics of the limbs. To tackle the control difficulties posed by various marine disturbances, an innovative composite control scheme is proposed. This scheme employs a non-singular terminal sliding mode control, designed using a double power reaching law, to enhance tracking speed and vibration suppression. Additionally, a disturbance estimator is developed to mitigate external disturbances by generating a compensatory signal on the input channel that counteracts the effects of these disturbances. Theoretical analysis confirms the stability of the proposed approach, while simulation results further demonstrate its effectiveness and superior performance.

{"title":"Dynamic characteristics analysis and multi-source disturbances rejection control of a 6-PUS parallel stabilization mechanism on floating base","authors":"Chaoxiong Lin , Baogeng Xin , Shuojie Wang , Songlin Zhou , Weixing Chen , Feng Gao","doi":"10.1016/j.mechmachtheory.2024.105888","DOIUrl":"10.1016/j.mechmachtheory.2024.105888","url":null,"abstract":"<div><div>The safety and efficiency of marine transfers are significantly influenced by the vessel motion under random wave excitations. The conventional ship-mounted stabilization platforms based on the Stewart-Gough platform design face limitations such as inadequate vertical workspace and additional inertial forces. To overcome these challenges, this study introduces a novel parallel stabilization mechanism, with kinematic and dynamic models that incorporate the motion of the floating base and the inertia characteristics of the limbs. To tackle the control difficulties posed by various marine disturbances, an innovative composite control scheme is proposed. This scheme employs a non-singular terminal sliding mode control, designed using a double power reaching law, to enhance tracking speed and vibration suppression. Additionally, a disturbance estimator is developed to mitigate external disturbances by generating a compensatory signal on the input channel that counteracts the effects of these disturbances. Theoretical analysis confirms the stability of the proposed approach, while simulation results further demonstrate its effectiveness and superior performance.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105888"},"PeriodicalIF":4.5,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Generalized optimization approach to design in-plane distributed compliant remote center of motion mechanism

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2024-12-20 DOI: 10.1016/j.mechmachtheory.2024.105890

Zhaowei Zhang , Michael Pieber , Johannes Gerstmayr

Remote center of motion (RCM) mechanisms are widely used because their center of rotation is outside the mechanical device. Usually, compliant RCM mechanisms use a linkage-based design with flexure hinges to achieve relative motion. It is still an open question to design a distributed compliant RCM mechanism using flexural beams. Addressing this, the paper proposes a generalized optimization approach for the design. The optimization approach is implemented in two steps. First, we use beams to establish a dual-layer ground structure. Using a genetic algorithm and considering the relative density of beams as variables, we obtain the optimized topology. Second, based on the topology and employing curved beams for size-shape optimization, we achieve optimized distributed compliant RCM mechanisms. Based on this approach, we explore and identify four distinct topologies and four detailed distributed compliant RCM mechanisms. With the comparison of stiffnesses and rotational axis shift, two kinds of optimized distributed compliant RCM mechanisms are considered. For verification, the commercial finite element software ABAQUS and experimental testing were utilized, demonstrating excellent alignment. Ultimately, this approach can be generalized for optimizing distributed compliant RCM mechanisms.

{"title":"Generalized optimization approach to design in-plane distributed compliant remote center of motion mechanism","authors":"Zhaowei Zhang , Michael Pieber , Johannes Gerstmayr","doi":"10.1016/j.mechmachtheory.2024.105890","DOIUrl":"10.1016/j.mechmachtheory.2024.105890","url":null,"abstract":"<div><div>Remote center of motion (RCM) mechanisms are widely used because their center of rotation is outside the mechanical device. Usually, compliant RCM mechanisms use a linkage-based design with flexure hinges to achieve relative motion. It is still an open question to design a distributed compliant RCM mechanism using flexural beams. Addressing this, the paper proposes a generalized optimization approach for the design. The optimization approach is implemented in two steps. First, we use beams to establish a dual-layer ground structure. Using a genetic algorithm and considering the relative density of beams as variables, we obtain the optimized topology. Second, based on the topology and employing curved beams for size-shape optimization, we achieve optimized distributed compliant RCM mechanisms. Based on this approach, we explore and identify four distinct topologies and four detailed distributed compliant RCM mechanisms. With the comparison of stiffnesses and rotational axis shift, two kinds of optimized distributed compliant RCM mechanisms are considered. For verification, the commercial finite element software ABAQUS and experimental testing were utilized, demonstrating excellent alignment. Ultimately, this approach can be generalized for optimizing distributed compliant RCM mechanisms.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105890"},"PeriodicalIF":4.5,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

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Mechanism and Machine Theory

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