Mahshid Mansouri, Elizabeth Hsiao-Wecksler, Girish Krishnan
Patients who have limited body movement ability need assistance with frequent repositioning and transfers from their caregivers. These common manual tasks are physically strenuous for caregivers. To minimize caregiver physical effort, several assistive devices have been proposed. However, most devices have complex designs, are expensive, can only move the patient in one direction, or still need the caregiver's intervention. Inspired by natural waves such as water waves that can carry objects, this study presents actuator-agnostic design guidelines for moving a body on a bed surface using traveling waves as an alternative solution. Specifically, this study explores how transportation speed and movement smoothness are affected by wave parameters such as the wavelength, wave amplitude, number of the actuators used to create the wave profile, and their movement pattern. Additional requirements for moving an elastic object, such as a human body, were also established to minimize the stiffness of the interface layer between the body and wave particles. Results suggest that transportation speed is linearly proportional to wave frequency and horizontal displacement of the wave actuators. Maximizing the number of actuators while minimizing wave amplitude and wavelength will increase the smoothness. Meanwhile, the wavelength must be at least half of the object length to ensure motion stability while also exceeding a critical value to guarantee that feasible waves are achieved in practice. Additionally, the wavelength, wave amplitude, and number of actuators will determine the minimum required stiffness of the interface layer.
{"title":"Towards Design Guidelines for Multidirectional Patient Transfer on a Bed Surface Using Traveling Waves","authors":"Mahshid Mansouri, Elizabeth Hsiao-Wecksler, Girish Krishnan","doi":"10.1115/1.4063573","DOIUrl":"https://doi.org/10.1115/1.4063573","url":null,"abstract":"Patients who have limited body movement ability need assistance with frequent repositioning and transfers from their caregivers. These common manual tasks are physically strenuous for caregivers. To minimize caregiver physical effort, several assistive devices have been proposed. However, most devices have complex designs, are expensive, can only move the patient in one direction, or still need the caregiver's intervention. Inspired by natural waves such as water waves that can carry objects, this study presents actuator-agnostic design guidelines for moving a body on a bed surface using traveling waves as an alternative solution. Specifically, this study explores how transportation speed and movement smoothness are affected by wave parameters such as the wavelength, wave amplitude, number of the actuators used to create the wave profile, and their movement pattern. Additional requirements for moving an elastic object, such as a human body, were also established to minimize the stiffness of the interface layer between the body and wave particles. Results suggest that transportation speed is linearly proportional to wave frequency and horizontal displacement of the wave actuators. Maximizing the number of actuators while minimizing wave amplitude and wavelength will increase the smoothness. Meanwhile, the wavelength must be at least half of the object length to ensure motion stability while also exceeding a critical value to guarantee that feasible waves are achieved in practice. Additionally, the wavelength, wave amplitude, and number of actuators will determine the minimum required stiffness of the interface layer.","PeriodicalId":49155,"journal":{"name":"Journal of Mechanisms and Robotics-Transactions of the Asme","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136078207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract Mechanical interference and singularities within the reachable workspace often restrict the orientational workspace of parallel robots. Introducing kinematic redundancy can alleviate this limitation. This paper discusses the possibility to produce unlimited rotation of the platform of a tripedal (6 + 3)-degree-of-freedom kinematically redundant parallel robot. The articulated platform of such a robot has three degrees of mobility. The platforms considered here are planar linkages that contain either revolute or prismatic joints. It is shown that at least two revolute joints are required to produce unlimited rotation with appropriate design and initial configuration, while the platforms with two prismatic joints cannot produce such rotations without crossing a singularity.
{"title":"Exploiting the Kinematic Redundancy of a (6+3)-DoF Parallel Manipulator to Produce Unlimited Rotation of the Platform","authors":"Arda Yigit, David Breton, Clement Gosselin","doi":"10.1115/1.4063407","DOIUrl":"https://doi.org/10.1115/1.4063407","url":null,"abstract":"Abstract Mechanical interference and singularities within the reachable workspace often restrict the orientational workspace of parallel robots. Introducing kinematic redundancy can alleviate this limitation. This paper discusses the possibility to produce unlimited rotation of the platform of a tripedal (6 + 3)-degree-of-freedom kinematically redundant parallel robot. The articulated platform of such a robot has three degrees of mobility. The platforms considered here are planar linkages that contain either revolute or prismatic joints. It is shown that at least two revolute joints are required to produce unlimited rotation with appropriate design and initial configuration, while the platforms with two prismatic joints cannot produce such rotations without crossing a singularity.","PeriodicalId":49155,"journal":{"name":"Journal of Mechanisms and Robotics-Transactions of the Asme","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136077389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract A new gripper design is proposed to offer grasping and scooping capabilities to a parallel robot. This enables the parallel robot to manipulate not only large objects, but also thin objects lying on flat surfaces. Moreover, this gripper is driven directly by the redundant degrees of freedom of the parallel robot to which it is integrated. Thus, by eliminating actuators from the gripper, weight is drastically reduced, thereby making it possible to take advantage of the full payload of the parallel robot. The kinematic architecture of the gripper is first presented, notably, the kinematic implications of using an epicyclic mechanism. Then, the kinematic model developed to integrate the gripper to a (6+3)-degree-of-freedom robot is presented. Trajectory planning strategies for both grasping and scooping are then presented together with the parameters used. Finally, the experimental validation of these manipulation methods is discussed briefly to assess foreseeable improvements to the gripper itself as well as the trajectory planning aspect of the manipulation methods.
{"title":"Kinematic Design and Prototyping of a Gripper with Grasping and Scooping Capabilities Driven by the Redundant Degrees of Freedom of a Parallel Robot","authors":"Charles-Antoine Beaulieu, Tan-Sy Nguyen, Thierry Laliberte, Clement Gosselin","doi":"10.1115/1.4063668","DOIUrl":"https://doi.org/10.1115/1.4063668","url":null,"abstract":"Abstract A new gripper design is proposed to offer grasping and scooping capabilities to a parallel robot. This enables the parallel robot to manipulate not only large objects, but also thin objects lying on flat surfaces. Moreover, this gripper is driven directly by the redundant degrees of freedom of the parallel robot to which it is integrated. Thus, by eliminating actuators from the gripper, weight is drastically reduced, thereby making it possible to take advantage of the full payload of the parallel robot. The kinematic architecture of the gripper is first presented, notably, the kinematic implications of using an epicyclic mechanism. Then, the kinematic model developed to integrate the gripper to a (6+3)-degree-of-freedom robot is presented. Trajectory planning strategies for both grasping and scooping are then presented together with the parameters used. Finally, the experimental validation of these manipulation methods is discussed briefly to assess foreseeable improvements to the gripper itself as well as the trajectory planning aspect of the manipulation methods.","PeriodicalId":49155,"journal":{"name":"Journal of Mechanisms and Robotics-Transactions of the Asme","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134976041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Zhengyu Wang, Xun Wei, Xiang Yu, Zirui Jia, Sen Qian, Daoming Wang
The accurate shape sensing capability of the continuum mechanism is fundamental to improve and guarantee the motion control accuracy and safety of continuum surgical robots. This paper presents a data-based shape self-sensing method for a cable-driven notched continuum mechanism using its multi-dimensional intrinsic force information, which mainly includes the multi-dimensional forces/torques and driving cable tensions, et al. The nonlinear hysteresis compensation and the shape estimation of the notched continuum mechanism play significant roles in its motion control. Calibration compensation of the notched continuum mechanism is performed based on kinematic modeling to improve the accuracy of its preliminary motion control. The hysteresis characteristics of the continuum mechanism is analyzed, modeled and compensated through considering the abundant dynamic motion experiments, such that a feedforward hysteresis compensation controller is designed to improve the tracking control performance of continuum mechanism. Based on the kinematics calibration and hysteresis compensation, combined with the motor displacement, driving cable tensions and six-dimensional forces/torques information of the continuum mechanism, a data-based shape self-sensing method based on Particle Swarm Optimization BP Neural Network (PSO-BPNN) is proposed in this study. Experimental results show that this method can effectively estimate the loaded and unloaded shape of the notched continuum mechanism, which provides a new approach for the shape reconstruction of cable-driven notched continuum surgical robots.
{"title":"Data-based Shape Self-sensing of a Cable-Driven Notched Continuum Mechanism Using Multi-dimensional Intrinsic Force Information for Surgical Robot","authors":"Zhengyu Wang, Xun Wei, Xiang Yu, Zirui Jia, Sen Qian, Daoming Wang","doi":"10.1115/1.4063369","DOIUrl":"https://doi.org/10.1115/1.4063369","url":null,"abstract":"\u0000 The accurate shape sensing capability of the continuum mechanism is fundamental to improve and guarantee the motion control accuracy and safety of continuum surgical robots. This paper presents a data-based shape self-sensing method for a cable-driven notched continuum mechanism using its multi-dimensional intrinsic force information, which mainly includes the multi-dimensional forces/torques and driving cable tensions, et al. The nonlinear hysteresis compensation and the shape estimation of the notched continuum mechanism play significant roles in its motion control. Calibration compensation of the notched continuum mechanism is performed based on kinematic modeling to improve the accuracy of its preliminary motion control. The hysteresis characteristics of the continuum mechanism is analyzed, modeled and compensated through considering the abundant dynamic motion experiments, such that a feedforward hysteresis compensation controller is designed to improve the tracking control performance of continuum mechanism. Based on the kinematics calibration and hysteresis compensation, combined with the motor displacement, driving cable tensions and six-dimensional forces/torques information of the continuum mechanism, a data-based shape self-sensing method based on Particle Swarm Optimization BP Neural Network (PSO-BPNN) is proposed in this study. Experimental results show that this method can effectively estimate the loaded and unloaded shape of the notched continuum mechanism, which provides a new approach for the shape reconstruction of cable-driven notched continuum surgical robots.","PeriodicalId":49155,"journal":{"name":"Journal of Mechanisms and Robotics-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43585006","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jing-Shan Zhao, Xiao-Cheng Sun, Song-Tao Wei, Wen-Xiu Lu
To reform the traditional concrete formwork, an overconstrained deployable frame is designed. It is composed of closed-loop deployable units formed by scissor-form elements and orthogonal telescoping rods. Using the reciprocal screw theory, the mobility of the deployable frame is studied, and it has one degree of freedom (DoF). To analyze the kinematic performance of the frame in the deployment and folding processes and the static characteristics under external loads at different deployed states, a general approach to analyzing the kinematics and statics by modeling in screw form is proposed. The velocities of joints could be solved in screw coordinates, the position and acceleration of joints could be obtained via a first-order numerical integration and a first-order numerical differential interpolation, respectively. Then, the position information for each joint can be forwarded onto the static equilibrium equations. Through the static analysis at each deployed state, the inner forces in each rod and the active control forces are derived. Kinematics and statics are associated by using velocities as the global variable, which allows a unified analysis of mechanisms. This method is computationally highly efficient and also fits for kinematic and static analysis of different kinds of multi-rigid-body mechanisms.
{"title":"Kinetostatics of Deployable Concrete Formworks","authors":"Jing-Shan Zhao, Xiao-Cheng Sun, Song-Tao Wei, Wen-Xiu Lu","doi":"10.1115/1.4063371","DOIUrl":"https://doi.org/10.1115/1.4063371","url":null,"abstract":"\u0000 To reform the traditional concrete formwork, an overconstrained deployable frame is designed. It is composed of closed-loop deployable units formed by scissor-form elements and orthogonal telescoping rods. Using the reciprocal screw theory, the mobility of the deployable frame is studied, and it has one degree of freedom (DoF). To analyze the kinematic performance of the frame in the deployment and folding processes and the static characteristics under external loads at different deployed states, a general approach to analyzing the kinematics and statics by modeling in screw form is proposed. The velocities of joints could be solved in screw coordinates, the position and acceleration of joints could be obtained via a first-order numerical integration and a first-order numerical differential interpolation, respectively. Then, the position information for each joint can be forwarded onto the static equilibrium equations. Through the static analysis at each deployed state, the inner forces in each rod and the active control forces are derived. Kinematics and statics are associated by using velocities as the global variable, which allows a unified analysis of mechanisms. This method is computationally highly efficient and also fits for kinematic and static analysis of different kinds of multi-rigid-body mechanisms.","PeriodicalId":49155,"journal":{"name":"Journal of Mechanisms and Robotics-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42790057","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The 2022 Best Paper Award is given to the paper recognized by the Editor and Editorial Board for its outstanding contribution to the field of mechanisms and robotics published by JMR in 2022. The prize includes a wall plaque for each author and will be announced in the journal, on JMR's companion website (asmejmr.org), and through the journal's online social media channels.
{"title":"Announcing the 2022 Best Paper Award and Honorable Mentions","authors":"V. Krovi","doi":"10.1115/1.4063372","DOIUrl":"https://doi.org/10.1115/1.4063372","url":null,"abstract":"\u0000 The 2022 Best Paper Award is given to the paper recognized by the Editor and Editorial Board for its outstanding contribution to the field of mechanisms and robotics published by JMR in 2022. The prize includes a wall plaque for each author and will be announced in the journal, on JMR's companion website (asmejmr.org), and through the journal's online social media channels.","PeriodicalId":49155,"journal":{"name":"Journal of Mechanisms and Robotics-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45033828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Compliant mechanisms, which can be integrally machined and without assembly, are well suited as joints for continuum robots (CRs), but how to incorporate the advantages of the compliant mechanism into the arm design is a key issue in this work. In this paper, a novel type of flexible spherical-hinged (FSH) joint composed of tetrahedron elements with a fixed virtual remote center of motion (RCM) at the bottom is proposed, and then extended to the CR and end-effector. In the arm design, the error compensation principle is used to offset the parasitic motion of the CR under external load (pressure and torque) and improve the bending and torsional isotropy of the arm through different series combinations, and then the stiffness model of the FSH joint and the statics model of the CR are developed using the 3D chain pseudo-rigid body model (3D-CPRBM) and tested. The results show that the 3D-CPRBM can effectively predict the deformation of the FSH joint and the CR. Moreover, the maximum standard deviation of the bending angle of the FSH joint in each direction is only 0.26 degree, the repeatable positioning accuracy of the CR can reach 0.5 degree, and the end-effector has good gripping ability and self-adaptive capability.
{"title":"Design of A Novel Flexible Spherical Hinge and Its Application in Continuum Robot","authors":"Guoxin Li, Jingjun Yu, Jie Pan, X. Pei","doi":"10.1115/1.4063370","DOIUrl":"https://doi.org/10.1115/1.4063370","url":null,"abstract":"\u0000 Compliant mechanisms, which can be integrally machined and without assembly, are well suited as joints for continuum robots (CRs), but how to incorporate the advantages of the compliant mechanism into the arm design is a key issue in this work. In this paper, a novel type of flexible spherical-hinged (FSH) joint composed of tetrahedron elements with a fixed virtual remote center of motion (RCM) at the bottom is proposed, and then extended to the CR and end-effector. In the arm design, the error compensation principle is used to offset the parasitic motion of the CR under external load (pressure and torque) and improve the bending and torsional isotropy of the arm through different series combinations, and then the stiffness model of the FSH joint and the statics model of the CR are developed using the 3D chain pseudo-rigid body model (3D-CPRBM) and tested. The results show that the 3D-CPRBM can effectively predict the deformation of the FSH joint and the CR. Moreover, the maximum standard deviation of the bending angle of the FSH joint in each direction is only 0.26 degree, the repeatable positioning accuracy of the CR can reach 0.5 degree, and the end-effector has good gripping ability and self-adaptive capability.","PeriodicalId":49155,"journal":{"name":"Journal of Mechanisms and Robotics-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46198870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The deployment of manipulators enhances the versatility and flexibility of unmanned aerial vehicles (UAVs) in aerial physical interaction tasks but also challenges their designs and controls due to variations in the center of gravity (CoG), moment of inertia and reaction wrenches. This work presents a novel design of a two-degree-of-freedom dual-tool manipulator with invariant-center-of-gravity (ICoG) property. The ICoG conditions are strictly deduced, and a practical optimization-based parameter tuning method is proposed. A novel adaptive-extended-state-observer-based (AESO-based) impedance control method is developed with actuator dynamics taken into account. The AESO can estimate and compensate for both the lumped disturbance, including the influences of moment-of-inertia variation and counter torque, and the unmeasurable states for the controller. In addition, a switching adaptive law is proposed to attenuate the peaking phenomenon under high observer gains. The impedance controller is designed using an auxiliary impedance tracking error to overcome the difficulty of the increased system order. The Lyapunov approach is used to evaluate the stability of the entire system. The proposed approach is implemented on a fully-actuated hexarotor with a prototype of the ICoG manipulator. Comparative experiments are conducted to validate the effectiveness and advantages of the proposed design and control methods.
{"title":"Design and Control of an Aerial Manipulator with Invariant Center of Gravity for Physical Interaction","authors":"Yongfeng Rong, Wusheng Chou","doi":"10.1115/1.4063368","DOIUrl":"https://doi.org/10.1115/1.4063368","url":null,"abstract":"\u0000 The deployment of manipulators enhances the versatility and flexibility of unmanned aerial vehicles (UAVs) in aerial physical interaction tasks but also challenges their designs and controls due to variations in the center of gravity (CoG), moment of inertia and reaction wrenches. This work presents a novel design of a two-degree-of-freedom dual-tool manipulator with invariant-center-of-gravity (ICoG) property. The ICoG conditions are strictly deduced, and a practical optimization-based parameter tuning method is proposed. A novel adaptive-extended-state-observer-based (AESO-based) impedance control method is developed with actuator dynamics taken into account. The AESO can estimate and compensate for both the lumped disturbance, including the influences of moment-of-inertia variation and counter torque, and the unmeasurable states for the controller. In addition, a switching adaptive law is proposed to attenuate the peaking phenomenon under high observer gains. The impedance controller is designed using an auxiliary impedance tracking error to overcome the difficulty of the increased system order. The Lyapunov approach is used to evaluate the stability of the entire system. The proposed approach is implemented on a fully-actuated hexarotor with a prototype of the ICoG manipulator. Comparative experiments are conducted to validate the effectiveness and advantages of the proposed design and control methods.","PeriodicalId":49155,"journal":{"name":"Journal of Mechanisms and Robotics-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44433873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Clustered tensegrity mechanisms have elicited extensive attention in recent research due to their easy control system and high stiffness-to-mass ratio. However, modeling and analyzing these mechanisms are still challenging due to the clustering of cables and redundant structural parameters. This paper proposes an energy-based kinematic modeling method for a modular clustered tensegrity mobile robot. The design of the clustered tensegrity robot is inspired by the biomechanics of worms, allowing it to achieve two locomotion modes resembling earthworm-like and inchworm-like movements using two motors. Moreover, the clustered and modular structure enables the robot to increase the number of modules as needed without increasing the number of actuators. This feature enhances the robot's terrain adaptability without adding complexity to the control system. The paper establishes kinematic models using the energy method and clarifies the motion law of nodes on the sliding cables of the robot, considering multiple structural parameters for both locomotion modes. Based on these models, the paper reveals the mapping relationships among various structural parameters (i.e., cable-hole gap, cable-hole friction, stiffness and original length of elastic cables, and ground-robot friction) and locomotion performance (i.e., morphology, displacement, and velocity) of the robot. Furthermore, structural parameter optimization is performed to enhance the kinematic performance of the robot in both locomotion modes simultaneously. A prototype with two modules is developed, and experiments are conducted to assess the robot's locomotion performance. These experiments demonstrate the effectiveness and rationality of the proposed method.
{"title":"Kinematic modeling and optimization of a clustered tensegrity mobile robot","authors":"Qi Yang, Xinyu Liu, Ze Yu, Binbin Lian, Tao Sun","doi":"10.1115/1.4063290","DOIUrl":"https://doi.org/10.1115/1.4063290","url":null,"abstract":"\u0000 Clustered tensegrity mechanisms have elicited extensive attention in recent research due to their easy control system and high stiffness-to-mass ratio. However, modeling and analyzing these mechanisms are still challenging due to the clustering of cables and redundant structural parameters. This paper proposes an energy-based kinematic modeling method for a modular clustered tensegrity mobile robot. The design of the clustered tensegrity robot is inspired by the biomechanics of worms, allowing it to achieve two locomotion modes resembling earthworm-like and inchworm-like movements using two motors. Moreover, the clustered and modular structure enables the robot to increase the number of modules as needed without increasing the number of actuators. This feature enhances the robot's terrain adaptability without adding complexity to the control system. The paper establishes kinematic models using the energy method and clarifies the motion law of nodes on the sliding cables of the robot, considering multiple structural parameters for both locomotion modes. Based on these models, the paper reveals the mapping relationships among various structural parameters (i.e., cable-hole gap, cable-hole friction, stiffness and original length of elastic cables, and ground-robot friction) and locomotion performance (i.e., morphology, displacement, and velocity) of the robot. Furthermore, structural parameter optimization is performed to enhance the kinematic performance of the robot in both locomotion modes simultaneously. A prototype with two modules is developed, and experiments are conducted to assess the robot's locomotion performance. These experiments demonstrate the effectiveness and rationality of the proposed method.","PeriodicalId":49155,"journal":{"name":"Journal of Mechanisms and Robotics-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41620545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cable-driven parallel manipulators and parallel continuum manipulators have attracted increasing attention in pick-and-place manipulation, owing to their low inertia and high safety. In cable-driven parallel robots, cables are utilized to control a moving platform, whereas parallel continuum manipulators employ flexible limbs.By combing these two types of mechanisms, the authors propose a novel flexible limb/cable hybrid-driven parallel continuum manipulator (HDPCM).The flexible limbs, equipped with their ability to withstand pushing forces applied on the moving platform, are a critical component of the HDPCM. Meanwhile, the cables, with their proficiency to modulate the shape of the flexible limbs and endure some of the pulling force, reduce the possibility of large divergence in flexible limbs. This results in an improved reachable workspace and load capacity for the manipulator. To predict the configuration of the proposed manipulator, an efficient kinetostaics analysis is given, utilizing a discretization-based approach. Among the infinitely many solutions to the inverse problem, the configuration with the minimal potential energy is selected as the optimal solution. Finally, a prototype is fabricated, and validation experiments are conducted, which demonstrate that the prototype exhibits acceptable positioning accuracy and passive compliance. Furthermore, the proposed manipulator is validated to possess relatively superior performance in workspace and load capacity.
{"title":"Analysis and Validation of a Flexible Limb/Cable Hybrid-Driven Parallel Continuum Manipulator","authors":"Yezheng Kang, Zhenkun Liang, Tianyi Yan, Xuyang Duan, Hao Wang, J. Seidelmann, Genliang Chen","doi":"10.1115/1.4063289","DOIUrl":"https://doi.org/10.1115/1.4063289","url":null,"abstract":"\u0000 Cable-driven parallel manipulators and parallel continuum manipulators have attracted increasing attention in pick-and-place manipulation, owing to their low inertia and high safety. In cable-driven parallel robots, cables are utilized to control a moving platform, whereas parallel continuum manipulators employ flexible limbs.By combing these two types of mechanisms, the authors propose a novel flexible limb/cable hybrid-driven parallel continuum manipulator (HDPCM).The flexible limbs, equipped with their ability to withstand pushing forces applied on the moving platform, are a critical component of the HDPCM. Meanwhile, the cables, with their proficiency to modulate the shape of the flexible limbs and endure some of the pulling force, reduce the possibility of large divergence in flexible limbs. This results in an improved reachable workspace and load capacity for the manipulator. To predict the configuration of the proposed manipulator, an efficient kinetostaics analysis is given, utilizing a discretization-based approach. Among the infinitely many solutions to the inverse problem, the configuration with the minimal potential energy is selected as the optimal solution. Finally, a prototype is fabricated, and validation experiments are conducted, which demonstrate that the prototype exhibits acceptable positioning accuracy and passive compliance. Furthermore, the proposed manipulator is validated to possess relatively superior performance in workspace and load capacity.","PeriodicalId":49155,"journal":{"name":"Journal of Mechanisms and Robotics-Transactions of the Asme","volume":" ","pages":""},"PeriodicalIF":2.6,"publicationDate":"2023-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49613805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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