F. Trautwein, David Dietrich, A. Pott, Alexander Verl
This paper presents a strategy for stable topological In-Operation-Reconfiguration of Cable-Driven Parallel Robots. Hereby, the term topological refers to the addition or removal of active cables and, thus, changing the topology of the cable robot. During the whole reconfiguration process, the strategy guarantees platform stability by considering a stability criterion that is based on potential energy. In this context, two new formulations of a stable and minimal-stable workspace are introduced. Consequently, the theoretical foundations of kinematics and statics are introduced first. Based on that, limitations in conventional modelling approaches in context of topological reconfiguration are outlined and necessary adaptions of the modelling are made. Afterwards, impacts of topological adaptions are analysed, followed by a formal description and a strategy for topological In-Operation-Reconfiguration. Conclusively, the reconfiguration strategy is applied to two simulation experiments, which show that the method is suitable to determine a stable reconfiguration sequence for the desired adaption of the robot.
{"title":"Strategy for Topological Reconfiguration of Cable-Driven Parallel Robots","authors":"F. Trautwein, David Dietrich, A. Pott, Alexander Verl","doi":"10.1115/1.4065642","DOIUrl":"https://doi.org/10.1115/1.4065642","url":null,"abstract":"\u0000 This paper presents a strategy for stable topological In-Operation-Reconfiguration of Cable-Driven Parallel Robots. Hereby, the term topological refers to the addition or removal of active cables and, thus, changing the topology of the cable robot. During the whole reconfiguration process, the strategy guarantees platform stability by considering a stability criterion that is based on potential energy. In this context, two new formulations of a stable and minimal-stable workspace are introduced. Consequently, the theoretical foundations of kinematics and statics are introduced first. Based on that, limitations in conventional modelling approaches in context of topological reconfiguration are outlined and necessary adaptions of the modelling are made. Afterwards, impacts of topological adaptions are analysed, followed by a formal description and a strategy for topological In-Operation-Reconfiguration. Conclusively, the reconfiguration strategy is applied to two simulation experiments, which show that the method is suitable to determine a stable reconfiguration sequence for the desired adaption of the robot.","PeriodicalId":508172,"journal":{"name":"Journal of Mechanisms and Robotics","volume":"3 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141271984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tri-Hieu Nguyen, Huy-Tuan Pham, N. Tran, Dung-An Wang
A kinetostatic model of an asymmetrical double stepped beam under axial loading is developed. The beam is composed of two thick segments and three thin segments where a thick segment is between two thin segments, and the longitudinal axis of the thick segment is not colinear with that of the thin segment. The kinetostatic model based on the beam constraint model (BCM) is capable of predicting accurate bending and near buckling behaviours of the beam. A virtual rigid link neighbouring the non-colinear segments is introduced in the BCM to broaden the applicability of the BCM. An analytical formula to represent the critical load of a symmetrical double stepped beam under axial loading is derived and the value calculated by the formula agrees with the limit load of the asymmetrical double stepped beam within the elastic range. The investigated beam has potential applications in displacement amplifiers and robotic grippers.
{"title":"Kinetostatic modeling of an asymmetrical double stepped beam for displacement amplification","authors":"Tri-Hieu Nguyen, Huy-Tuan Pham, N. Tran, Dung-An Wang","doi":"10.1115/1.4065521","DOIUrl":"https://doi.org/10.1115/1.4065521","url":null,"abstract":"\u0000 A kinetostatic model of an asymmetrical double stepped beam under axial loading is developed. The beam is composed of two thick segments and three thin segments where a thick segment is between two thin segments, and the longitudinal axis of the thick segment is not colinear with that of the thin segment. The kinetostatic model based on the beam constraint model (BCM) is capable of predicting accurate bending and near buckling behaviours of the beam. A virtual rigid link neighbouring the non-colinear segments is introduced in the BCM to broaden the applicability of the BCM. An analytical formula to represent the critical load of a symmetrical double stepped beam under axial loading is derived and the value calculated by the formula agrees with the limit load of the asymmetrical double stepped beam within the elastic range. The investigated beam has potential applications in displacement amplifiers and robotic grippers.","PeriodicalId":508172,"journal":{"name":"Journal of Mechanisms and Robotics","volume":"131 18","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140977237","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Euler-Lagrange's formulation is known for its systematic and simplified approach in deriving dynamics of complex systems. In order to apply the existing formulation to human gait dynamics, the base reference frame must be assumed as an inertial reference frame. Conventionally, the ankle joint or the hip joint are regarded as base reference frames during the stance and swing phase of human walking. As these joints are non-inertial in nature during actual locomotion, this assumption could result in inaccurate calculation of lower-limb joint torques and forces. Therefore, in this paper, an existing Euler-Lagrange based formulation originally developed for fixed-base robotic manipulators is considered and modified to accommodate the movement of the base reference frame with respect to an inertial frame of reference defined outside the human body. The applicability of the modified formulation is studied, implemented, and validated using three standard and publicly available gait datasets covering the phases of walking and running. The joint torques obtained using the proposed dynamic model are compared with reference torques by calculating the mean absolute error values and visually through Bland-Altman plots. The obtained joint torque values and plots indicate a close agreement with published torques, thereby validating the accuracy of the proposed dynamic model. The robust formulation implementation makes it a valuable resource for researchers in this field, offering a reliable framework for gait analysis and the design of lower-limb prosthetics or exoskeletons.
{"title":"Enhanced Euler-Lagrange Formulation for Analyzing Human Gait with Moving Base Reference","authors":"Sekar Anup Chander, Ashutosh Mukherjee, Vhatkar Dattatraya Shivling, Ashish Singla","doi":"10.1115/1.4065520","DOIUrl":"https://doi.org/10.1115/1.4065520","url":null,"abstract":"\u0000 Euler-Lagrange's formulation is known for its systematic and simplified approach in deriving dynamics of complex systems. In order to apply the existing formulation to human gait dynamics, the base reference frame must be assumed as an inertial reference frame. Conventionally, the ankle joint or the hip joint are regarded as base reference frames during the stance and swing phase of human walking. As these joints are non-inertial in nature during actual locomotion, this assumption could result in inaccurate calculation of lower-limb joint torques and forces. Therefore, in this paper, an existing Euler-Lagrange based formulation originally developed for fixed-base robotic manipulators is considered and modified to accommodate the movement of the base reference frame with respect to an inertial frame of reference defined outside the human body. The applicability of the modified formulation is studied, implemented, and validated using three standard and publicly available gait datasets covering the phases of walking and running. The joint torques obtained using the proposed dynamic model are compared with reference torques by calculating the mean absolute error values and visually through Bland-Altman plots. The obtained joint torque values and plots indicate a close agreement with published torques, thereby validating the accuracy of the proposed dynamic model. The robust formulation implementation makes it a valuable resource for researchers in this field, offering a reliable framework for gait analysis and the design of lower-limb prosthetics or exoskeletons.","PeriodicalId":508172,"journal":{"name":"Journal of Mechanisms and Robotics","volume":"47 26","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140974997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rigid foldability is a special property of rigid origami patterns, where each origami plane remains undeformed during continuous movement along the predetermined crease. Current research on the rigid foldability of origami patterns mainly focuses on kinematics, while less attention is paid to factors that cause deformation of the folding plane. Whether the relative spatial position of adjacent creases has been changed is a critical factor that influences the state (rigid or deformed) of the folding plane between the two adjacent creases during the folding process. This study considered two factors (linear relationship and Euclidean distance) to measure the changes in the spatial positions of creases, explored the relationship between the two factors and rigid folding, and identified deformation forms that affects rigid foldability. First, the origami pattern was regarded as a linkage mechanism, and the linear relationship between creases was determined from the single-vertex origami unit forming this origami structure. Then, the geometric parameters of the origami pattern were used to calculate the Euclidean distance between two points on adjacent creases during the folding process. If the linear relationship and Euclidean distance always remain the same, the origami pattern has rigid foldability. Based on changes in Euclidean distance, this method can also help determine the main deformation of non-rigidly foldable origami patterns. In addition, it further provides a novel approach for determining the layout of the crease position and the judgment of rigid foldability during origami-inspired mechanism design.
{"title":"Analysis of the Rigid Foldability of Origami Patterns Based on Spatial Positions of Creases","authors":"Feng Wang, Fan Zhang, Guohua Cui","doi":"10.1115/1.4065461","DOIUrl":"https://doi.org/10.1115/1.4065461","url":null,"abstract":"\u0000 Rigid foldability is a special property of rigid origami patterns, where each origami plane remains undeformed during continuous movement along the predetermined crease. Current research on the rigid foldability of origami patterns mainly focuses on kinematics, while less attention is paid to factors that cause deformation of the folding plane. Whether the relative spatial position of adjacent creases has been changed is a critical factor that influences the state (rigid or deformed) of the folding plane between the two adjacent creases during the folding process. This study considered two factors (linear relationship and Euclidean distance) to measure the changes in the spatial positions of creases, explored the relationship between the two factors and rigid folding, and identified deformation forms that affects rigid foldability. First, the origami pattern was regarded as a linkage mechanism, and the linear relationship between creases was determined from the single-vertex origami unit forming this origami structure. Then, the geometric parameters of the origami pattern were used to calculate the Euclidean distance between two points on adjacent creases during the folding process. If the linear relationship and Euclidean distance always remain the same, the origami pattern has rigid foldability. Based on changes in Euclidean distance, this method can also help determine the main deformation of non-rigidly foldable origami patterns. In addition, it further provides a novel approach for determining the layout of the crease position and the judgment of rigid foldability during origami-inspired mechanism design.","PeriodicalId":508172,"journal":{"name":"Journal of Mechanisms and Robotics","volume":"54 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141016711","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soft linear actuators have strong deformation ability and good environmental adaptability, which have been widely used in soft robot design. However, little work has focused on designing soft linear actuators with balanced performances, featuring fast driving speed, large output displacement, lightweight, and miniaturization. Herein, we present a novel soft linear actuator design based on the Kresling origami structure. By driving the Kresling tubes with a servo motor, the soft linear actuator has good compliance and strong environmental adaptability and can achieve fast driving speed, large driving force, and high control precision comparable to the traditional electrical motor. The analytical models of the Kresling tubes and the whole actuator are respectively derived to analyze the mechanical properties, determine the optimal geometry of the Kresling tube and evaluate the driving performance of the whole actuator. The actuator prototype is fabricated by 3D printing, and the actual driving performance is tested. It is shown that the prototype can achieve a maximum output displacement of 18.9 mm without payload or 16mm under a payload of 30 N. Finally, as a case study, the soft linear actuator is applied to a crawling robot, where the maximum moving speed of 28 mm/s is reached.
软线性致动器具有较强的变形能力和良好的环境适应性，在软机器人设计中得到了广泛应用。然而，人们很少关注如何设计出性能均衡、驱动速度快、输出位移大、重量轻和小型化的软线性致动器。在此，我们提出了一种基于克瑞斯林折纸结构的新型软线性致动器设计。通过伺服电机驱动克瑞斯林管，软线性致动器具有良好的顺应性和较强的环境适应性，可实现与传统电机相媲美的快速驱动速度、较大驱动力和较高控制精度。分别推导了克瑞斯林管和整个致动器的分析模型，以分析其力学性能、确定克瑞斯林管的最佳几何形状并评估整个致动器的驱动性能。通过三维打印技术制作了致动器原型，并对其实际驱动性能进行了测试。结果表明，原型在无负载的情况下可实现 18.9 毫米的最大输出位移，在负载为 30 N 的情况下可实现 16 毫米的最大输出位移。最后，作为案例研究，将软线性致动器应用于爬行机器人，其最大移动速度达到 28 毫米/秒。
{"title":"An Origami-enabled Soft Linear Actuator and its Application on a Crawling Robot","authors":"Shuiqing Yan, Keyao Song, Xiashuang Wang, Jiake Li, Ma Zhe, Xiang Zhou","doi":"10.1115/1.4065462","DOIUrl":"https://doi.org/10.1115/1.4065462","url":null,"abstract":"\u0000 Soft linear actuators have strong deformation ability and good environmental adaptability, which have been widely used in soft robot design. However, little work has focused on designing soft linear actuators with balanced performances, featuring fast driving speed, large output displacement, lightweight, and miniaturization. Herein, we present a novel soft linear actuator design based on the Kresling origami structure. By driving the Kresling tubes with a servo motor, the soft linear actuator has good compliance and strong environmental adaptability and can achieve fast driving speed, large driving force, and high control precision comparable to the traditional electrical motor. The analytical models of the Kresling tubes and the whole actuator are respectively derived to analyze the mechanical properties, determine the optimal geometry of the Kresling tube and evaluate the driving performance of the whole actuator. The actuator prototype is fabricated by 3D printing, and the actual driving performance is tested. It is shown that the prototype can achieve a maximum output displacement of 18.9 mm without payload or 16mm under a payload of 30 N. Finally, as a case study, the soft linear actuator is applied to a crawling robot, where the maximum moving speed of 28 mm/s is reached.","PeriodicalId":508172,"journal":{"name":"Journal of Mechanisms and Robotics","volume":"61 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141016684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We demonstrate the general formulation of a method for conducting a kinematic analysis regarding the shape formed by multiple reference links on robotic mechanisms. In contrast to the standard kinematic analysis of robot manipulators that assumes having a single hand link configuration with respect to the base link, the formulated kinematic analysis regarding the shape is free from this assumption. Consequently, an analysis without specifying base link and that about shape defined by multiple reference links are possible. Moreover, the kinematic properties, which are invariant from the switching of base and hand links, can be obtained. First, a method to decompose motions of multiple bodies into rigid and non-rigid components is formulated. Then, the method is generalized considering the weights for translational and angular velocities. Next, Jacobian matrices that relate active joint velocities and non-rigid motions (change in the shape) of specified reference links on the robotic mechanism are defined. Subsequently, certain measures for evaluating shape controllability are defined based on the measures for evaluating hand configuration controllability of robot manipulators. Finally, some application examples using the defined measures are demonstrated.
{"title":"Analysis of Instantaneous Kinematic Properties regarding the Shape of Robotic Mechanisms","authors":"Keisuke Arikawa","doi":"10.1115/1.4065371","DOIUrl":"https://doi.org/10.1115/1.4065371","url":null,"abstract":"\u0000 We demonstrate the general formulation of a method for conducting a kinematic analysis regarding the shape formed by multiple reference links on robotic mechanisms. In contrast to the standard kinematic analysis of robot manipulators that assumes having a single hand link configuration with respect to the base link, the formulated kinematic analysis regarding the shape is free from this assumption. Consequently, an analysis without specifying base link and that about shape defined by multiple reference links are possible. Moreover, the kinematic properties, which are invariant from the switching of base and hand links, can be obtained. First, a method to decompose motions of multiple bodies into rigid and non-rigid components is formulated. Then, the method is generalized considering the weights for translational and angular velocities. Next, Jacobian matrices that relate active joint velocities and non-rigid motions (change in the shape) of specified reference links on the robotic mechanism are defined. Subsequently, certain measures for evaluating shape controllability are defined based on the measures for evaluating hand configuration controllability of robot manipulators. Finally, some application examples using the defined measures are demonstrated.","PeriodicalId":508172,"journal":{"name":"Journal of Mechanisms and Robotics","volume":"58 16","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140666888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tubular auxetic structures have wide-ranging applications including medical stents, collapsible energy absorbers, and novel fasteners. To expand development in these areas, and open up new application directions, an expanded range of design and construction methods for auxetic tubes is required. In this study we propose a new method to construct polygonal cross-section auxetic tubes using the principles of origami and kirigami. These tubes exhibit useful global auxetic behaviour under axial extension, despite the individual polygon faces not being auxetic themselves. A flat kirigami sheet cannot be simply folded into a polygonal tube since this creates kinematic incompatibilities along the polygon edges. This is resolved by replacing the edge folds with an origami mechanism consisting of a pair of triangular facets. This approach eliminates the incompatibilities at the edges while maintaining a connection between faces. The proposed edge connection also introduces additional control parameters for the tube kinematics: for example, introducing a kinematic limit on tube extension and enabling non-uniform behaviour along the length of the tube. The rich kinematic behaviour possible with polygonal cross-section kirigami tubes has potential applications ranging from soft robotics to energy-dissipating devices.
{"title":"Folding Auxetic Polygonal Kirigami Tubes","authors":"Martin Walker","doi":"10.1115/1.4065372","DOIUrl":"https://doi.org/10.1115/1.4065372","url":null,"abstract":"\u0000 Tubular auxetic structures have wide-ranging applications including medical stents, collapsible energy absorbers, and novel fasteners. To expand development in these areas, and open up new application directions, an expanded range of design and construction methods for auxetic tubes is required. In this study we propose a new method to construct polygonal cross-section auxetic tubes using the principles of origami and kirigami. These tubes exhibit useful global auxetic behaviour under axial extension, despite the individual polygon faces not being auxetic themselves. A flat kirigami sheet cannot be simply folded into a polygonal tube since this creates kinematic incompatibilities along the polygon edges. This is resolved by replacing the edge folds with an origami mechanism consisting of a pair of triangular facets. This approach eliminates the incompatibilities at the edges while maintaining a connection between faces. The proposed edge connection also introduces additional control parameters for the tube kinematics: for example, introducing a kinematic limit on tube extension and enabling non-uniform behaviour along the length of the tube. The rich kinematic behaviour possible with polygonal cross-section kirigami tubes has potential applications ranging from soft robotics to energy-dissipating devices.","PeriodicalId":508172,"journal":{"name":"Journal of Mechanisms and Robotics","volume":"9 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140666599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Remote actuated mechanisms that employ tendon sheaths or tether units can transmit mechanical force without directly connecting the actuators to the mechanism, but suffer from undesirable side effects like mechanical friction and induced external wrench disturbances on the distal side of the mechanism. In this work, a multiple shooting method is proposed as a superior method to the single shooting method to solve the Cosserat rod boundary value problems, to obtain the states of the system. With that, numerical experiments are provided to demonstrate the difficulty of solving these boundary value problems, simultaneously showing the validity of the proposed approach. 2D reconstruction experiments were conducted to show shape reconstruction capabilities. Additionally, friction loss and 6-DOF wrench estimations were also experimentally validated with the proposed mathematical model with 0.1679N and 0.0401Nm for RMSE force estimation and torque estimation error respectively, while achieving a 3% mean absolute percentage steady state friction estimation error. Lastly, a modified resolved rates controller was applied to steer a remote tendon-driven continuum robot to compensate for friction loss for 3.1m long tether units.
{"title":"Wrench estimation and friction compensation using multiple shooting method for tether units augmented to remote tendon-driven continuum robots","authors":"J. Chien, Clarissa Leong, Jingmin Liu, S. Foong","doi":"10.1115/1.4065370","DOIUrl":"https://doi.org/10.1115/1.4065370","url":null,"abstract":"\u0000 Remote actuated mechanisms that employ tendon sheaths or tether units can transmit mechanical force without directly connecting the actuators to the mechanism, but suffer from undesirable side effects like mechanical friction and induced external wrench disturbances on the distal side of the mechanism. In this work, a multiple shooting method is proposed as a superior method to the single shooting method to solve the Cosserat rod boundary value problems, to obtain the states of the system. With that, numerical experiments are provided to demonstrate the difficulty of solving these boundary value problems, simultaneously showing the validity of the proposed approach. 2D reconstruction experiments were conducted to show shape reconstruction capabilities. Additionally, friction loss and 6-DOF wrench estimations were also experimentally validated with the proposed mathematical model with 0.1679N and 0.0401Nm for RMSE force estimation and torque estimation error respectively, while achieving a 3% mean absolute percentage steady state friction estimation error. Lastly, a modified resolved rates controller was applied to steer a remote tendon-driven continuum robot to compensate for friction loss for 3.1m long tether units.","PeriodicalId":508172,"journal":{"name":"Journal of Mechanisms and Robotics","volume":"141 23","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140668821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In order to address the problem of functional rehabilitation after ankle fracture surgery. This paper presented a novel ankle fracture rehabilitation robot. The robot adopted R-3RRS-P hybrid structure, which was simple in structure and had two working modes: rehabilitation training and motion axis switching. Comparing with existing ankle rehabilitation robot, the proposed robot could simulate more realistic kinematics of ankle joint complex. Additionally, different body types of patients could be adapted. The kinematic and static models were established in detail using geometric method and screw theory. The coverage of the healthy ankle motion ability was formulated as an optimization problem to improve the robot performance. Multi-objective optimal design was carried out to determine the dimensional parameters. The interference-free working space was calculated by numerical method. A prototype of the proposed robot was developed, and a series of experiments were performed to evaluate the function and feasibility of the proposed robot.
{"title":"Design and experiment of an ankle rehabilitation robot after fracture surgery","authors":"Monan Ni, Jialin Liu, Zhenhui Sun, Tao Sun","doi":"10.1115/1.4065392","DOIUrl":"https://doi.org/10.1115/1.4065392","url":null,"abstract":"\u0000 In order to address the problem of functional rehabilitation after ankle fracture surgery. This paper presented a novel ankle fracture rehabilitation robot. The robot adopted R-3RRS-P hybrid structure, which was simple in structure and had two working modes: rehabilitation training and motion axis switching. Comparing with existing ankle rehabilitation robot, the proposed robot could simulate more realistic kinematics of ankle joint complex. Additionally, different body types of patients could be adapted. The kinematic and static models were established in detail using geometric method and screw theory. The coverage of the healthy ankle motion ability was formulated as an optimization problem to improve the robot performance. Multi-objective optimal design was carried out to determine the dimensional parameters. The interference-free working space was calculated by numerical method. A prototype of the proposed robot was developed, and a series of experiments were performed to evaluate the function and feasibility of the proposed robot.","PeriodicalId":508172,"journal":{"name":"Journal of Mechanisms and Robotics","volume":"52 18","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140667173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Foroogh Behroozi, Ramin Mersi, Antoine Benoist, Ru-Ying Yong, P. Cardou, Stéphane Caro
In the realm of cable-driven parallel robots (CDPRs), the conventional notion entails that each cable is directly actuated by a corresponding actuator, implying a direct relationship between the number of cables and actuators. However, this paper introduces a paradigm shift by contending that the number of cables should be contingent upon the desired workspace, while the number of actuators should align with the robot's degrees of freedom (DoF). This novel perspective leads to an unconventional design methodology for CDPRs. Instead of commencing with the number of actuators and cables in mind, we propose an approach that begins with defining the required workspace shape and determines the requisite number of cables. Subsequently, an actuation scheme is established where each actuator can drive multiple cables. This process entails the formulation of a transmission matrix that captures the interplay between actuators and cables, followed by the mechanical implementation of the corresponding cable-pulley routing. To illustrate this approach, we provide an example involving a 2-DoF CDPR aimed at covering a rectangular workspace. Notably, the resulting Wrench-Closure Workspace (WCW) and Wrench-Feasible Workspace (WFW) of the proposed designs exhibit favorable comparisons to existing CDPRs with more actuators.
{"title":"A Three-Actuator Cable-Driven Parallel Robot with a Rectangular Workspace","authors":"Foroogh Behroozi, Ramin Mersi, Antoine Benoist, Ru-Ying Yong, P. Cardou, Stéphane Caro","doi":"10.1115/1.4065393","DOIUrl":"https://doi.org/10.1115/1.4065393","url":null,"abstract":"\u0000 In the realm of cable-driven parallel robots (CDPRs), the conventional notion entails that each cable is directly actuated by a corresponding actuator, implying a direct relationship between the number of cables and actuators. However, this paper introduces a paradigm shift by contending that the number of cables should be contingent upon the desired workspace, while the number of actuators should align with the robot's degrees of freedom (DoF). This novel perspective leads to an unconventional design methodology for CDPRs. Instead of commencing with the number of actuators and cables in mind, we propose an approach that begins with defining the required workspace shape and determines the requisite number of cables. Subsequently, an actuation scheme is established where each actuator can drive multiple cables. This process entails the formulation of a transmission matrix that captures the interplay between actuators and cables, followed by the mechanical implementation of the corresponding cable-pulley routing. To illustrate this approach, we provide an example involving a 2-DoF CDPR aimed at covering a rectangular workspace. Notably, the resulting Wrench-Closure Workspace (WCW) and Wrench-Feasible Workspace (WFW) of the proposed designs exhibit favorable comparisons to existing CDPRs with more actuators.","PeriodicalId":508172,"journal":{"name":"Journal of Mechanisms and Robotics","volume":"105 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140669816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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