Yiqun Li, Jiahui Gao, Kai Chen, Wei Chen, Zhouping Yin
Abstract The wheel-legged robot inherits the merit of both the wheeled robot and the legged robot, which can not only adapt to the complex terrain, but also maintain the driving efficiency on the flat road. This paper presents an optimization-based approach that leverage ideas from computational geometric mechanics to generate safe and high-quality wheel-leg hybrid motions among obstacles. The formulation of the proposed motion optimization problem incorporates the Lagrange-d'Alembert principle as the robot's dynamic constraints and an efficient closed-form formulation of collision-free constraints. By discretizing the variational mechanics principle directly, rather than its corresponding forced Euler-Lagrange equation, the continuous trajectory optimization problem is transformed into a nonlinear programming (NLP) problem. Numerical simulations and several real-world experiments are conducted on a wheel-legged robot to demonstrate the effectiveness of the proposed trajectory generation approach.
{"title":"Safe Trajectory Generation for Wheel-Leg Hybrid Mechanism Using Discrete Mechanics and Optimal Control","authors":"Yiqun Li, Jiahui Gao, Kai Chen, Wei Chen, Zhouping Yin","doi":"10.1115/1.4063871","DOIUrl":"https://doi.org/10.1115/1.4063871","url":null,"abstract":"Abstract The wheel-legged robot inherits the merit of both the wheeled robot and the legged robot, which can not only adapt to the complex terrain, but also maintain the driving efficiency on the flat road. This paper presents an optimization-based approach that leverage ideas from computational geometric mechanics to generate safe and high-quality wheel-leg hybrid motions among obstacles. The formulation of the proposed motion optimization problem incorporates the Lagrange-d'Alembert principle as the robot's dynamic constraints and an efficient closed-form formulation of collision-free constraints. By discretizing the variational mechanics principle directly, rather than its corresponding forced Euler-Lagrange equation, the continuous trajectory optimization problem is transformed into a nonlinear programming (NLP) problem. Numerical simulations and several real-world experiments are conducted on a wheel-legged robot to demonstrate the effectiveness of the proposed trajectory generation approach.","PeriodicalId":49155,"journal":{"name":"Journal of Mechanisms and Robotics-Transactions of the Asme","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135569530","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 The SDelta is a three-limb, six-degrees-of-freedom parallel kinematics machine, a pertinent candidate for high-speed operations by virtue of its simple architecture. The original design of the SDelta includes a planar base and moving platforms. Here, we propose a novel architecture for an improved SDelta, the orthogonal SDelta (OSD), with a cube-shaped orthogonal base platform. Inverse and forward position models are reported, along with singularity and dexterity analyses. Moreover, design parameters and mechanical constraints leading to a singularity-free workspace are provided. An evaluation of the system translational workspace and orientational capability, upon consideration of volume and dexterity, is included. The SDelta as well as a generic 6SPS mechanism (C, P, and S denote, respectively, the cylindrical, prismatic, and spherical kinematic pairs, the actuated pair is represented underlined, as P) are designed with the same parameters, then the performance of the SDelta, the OSD, and the 6SPS mechanisms are being compared. The results show that the orientational capability of the OSD is better than those of the 6SPS and the SDelta. Furthermore, the OSD has an average condition number of 2.9 over its translational workspace and 1.69 over a predefined effective regular workspace, which make the OSD a good candidate for operations that need both a high orientational capability and high dexterity.
{"title":"Workspace, Singularity and Dexterity Analyses of a Six-dof SDelta Robot with an Orthogonal Base Platform","authors":"Metin Toz, Hasiaoqier Han, Jorge Angeles","doi":"10.1115/1.4063574","DOIUrl":"https://doi.org/10.1115/1.4063574","url":null,"abstract":"Abstract The SDelta is a three-limb, six-degrees-of-freedom parallel kinematics machine, a pertinent candidate for high-speed operations by virtue of its simple architecture. The original design of the SDelta includes a planar base and moving platforms. Here, we propose a novel architecture for an improved SDelta, the orthogonal SDelta (OSD), with a cube-shaped orthogonal base platform. Inverse and forward position models are reported, along with singularity and dexterity analyses. Moreover, design parameters and mechanical constraints leading to a singularity-free workspace are provided. An evaluation of the system translational workspace and orientational capability, upon consideration of volume and dexterity, is included. The SDelta as well as a generic 6SPS mechanism (C, P, and S denote, respectively, the cylindrical, prismatic, and spherical kinematic pairs, the actuated pair is represented underlined, as P) are designed with the same parameters, then the performance of the SDelta, the OSD, and the 6SPS mechanisms are being compared. The results show that the orientational capability of the OSD is better than those of the 6SPS and the SDelta. Furthermore, the OSD has an average condition number of 2.9 over its translational workspace and 1.69 over a predefined effective regular workspace, which make the OSD a good candidate for operations that need both a high orientational capability and high dexterity.","PeriodicalId":49155,"journal":{"name":"Journal of Mechanisms and Robotics-Transactions of the Asme","volume":"58 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135514274","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 In this work, a novel model called equivalent mechanical model (EMM) is presented. First, the character array based on the EMM is built. Further, a recursive formula for finding the elements in the character array is derived using improved adjacent matrix. Then, the method of isomorphism identification of kinematic chains and the principle of constructing isomorphic mapping are presented. Finally, three cases are discussed to test the validity of the method. The method endows the edges with recognition given by character arrays as the necessary condition for constructing mapping, and takes whether the constructed mapping satisfies the definition of isomorphism as the sufficient identification condition. The results show that the isomorphism identification conditions based on EMM can identify the isomorphism of kinematic chains accurately and reliably.
{"title":"The equivalent mechanical model of topological graphs and the isomorphism identification of kinematic chains","authors":"Wuxing Pan, Li Ruiqin","doi":"10.1115/1.4063869","DOIUrl":"https://doi.org/10.1115/1.4063869","url":null,"abstract":"Abstract In this work, a novel model called equivalent mechanical model (EMM) is presented. First, the character array based on the EMM is built. Further, a recursive formula for finding the elements in the character array is derived using improved adjacent matrix. Then, the method of isomorphism identification of kinematic chains and the principle of constructing isomorphic mapping are presented. Finally, three cases are discussed to test the validity of the method. The method endows the edges with recognition given by character arrays as the necessary condition for constructing mapping, and takes whether the constructed mapping satisfies the definition of isomorphism as the sufficient identification condition. The results show that the isomorphism identification conditions based on EMM can identify the isomorphism of kinematic chains accurately and reliably.","PeriodicalId":49155,"journal":{"name":"Journal of Mechanisms and Robotics-Transactions of the Asme","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135569988","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 This paper presents a novel geometric modeling method for direct displacement analysis of 6-4 Stewart platforms based on conformal geometric algebra (CGA). First, a geometric constraint relationship of four lines and a plane intersecting at a point is published. Second, a new coordinate-invariant geometric constraint equation of 6-4 Stewart platforms is deduced by CGA operation. Third, five polynomial equations are established by CGA theory. Fourth, based on the above six equations, a 5 × 5 Sylvester’s matrix is formulated by using Sylvester’s Dialytic elimination method and Gröbner bases method under the graded reverse lexicographical order. Finally, the coordinates of four points on the moving platform are revealed. Besides, a numerical example is used to prove the validity of the proposed method. The novelty of this study is that a whole geometric modeling method by geometric constraint relationship of four lines and a plane intersecting at a point is put forward under the CGA framework, which has good intuition and offers a novel idea for solving the other complex mechanisms. At the same time, Sylvester’s matrix constructed by this method is the smallest one in the known literature for forward displacement analysis of 6-4 Stewart platforms.
{"title":"CGA-based geometric modeling method for forward displacement analysis of 6-4 Stewart platforms","authors":"Ganmin Zhu, Shimin Wei, Duanling Li, Yingli Wang, Qizheng Liao","doi":"10.1115/1.4063501","DOIUrl":"https://doi.org/10.1115/1.4063501","url":null,"abstract":"Abstract This paper presents a novel geometric modeling method for direct displacement analysis of 6-4 Stewart platforms based on conformal geometric algebra (CGA). First, a geometric constraint relationship of four lines and a plane intersecting at a point is published. Second, a new coordinate-invariant geometric constraint equation of 6-4 Stewart platforms is deduced by CGA operation. Third, five polynomial equations are established by CGA theory. Fourth, based on the above six equations, a 5 × 5 Sylvester’s matrix is formulated by using Sylvester’s Dialytic elimination method and Gröbner bases method under the graded reverse lexicographical order. Finally, the coordinates of four points on the moving platform are revealed. Besides, a numerical example is used to prove the validity of the proposed method. The novelty of this study is that a whole geometric modeling method by geometric constraint relationship of four lines and a plane intersecting at a point is put forward under the CGA framework, which has good intuition and offers a novel idea for solving the other complex mechanisms. At the same time, Sylvester’s matrix constructed by this method is the smallest one in the known literature for forward displacement analysis of 6-4 Stewart platforms.","PeriodicalId":49155,"journal":{"name":"Journal of Mechanisms and Robotics-Transactions of the Asme","volume":"84 3","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135514405","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 For practical applications of interactive manipulation, active contact control is one of the fundamental functions that flexible-link parallel mechanisms (FLPMs) should be equipped with. In this paper, a force control approach is proposed for FLPMs to make active adjustment toward their payload, which cannot be directly achieved by their intrinsic passive compliance. To begin with, at a starting configuration the Jacobian matrix is accurately calculated with finite difference method, while at non-starting configurations it is deduced with an increment-based approach. The compliance model is derived through mapping from the joint stiffness within each elastic rod. On this basis, the differential relation among pose, payload and actuation variables is constructed to form the control logic, whose correctness and feasibility are then verified with simulations. Finally, interaction experiments under fixed environment and cooperative motion are carried out, and the results demonstrate that force control for a quasi-translational FLPM can be accomplished with enough pose accuracy.
{"title":"Active Control of Contact Force for a Quasi-Translational Flexible-Link Parallel Mechanism","authors":"Hao Pan, Shujie Tang, Genliang Chen, Hao Wang","doi":"10.1115/1.4063870","DOIUrl":"https://doi.org/10.1115/1.4063870","url":null,"abstract":"Abstract For practical applications of interactive manipulation, active contact control is one of the fundamental functions that flexible-link parallel mechanisms (FLPMs) should be equipped with. In this paper, a force control approach is proposed for FLPMs to make active adjustment toward their payload, which cannot be directly achieved by their intrinsic passive compliance. To begin with, at a starting configuration the Jacobian matrix is accurately calculated with finite difference method, while at non-starting configurations it is deduced with an increment-based approach. The compliance model is derived through mapping from the joint stiffness within each elastic rod. On this basis, the differential relation among pose, payload and actuation variables is constructed to form the control logic, whose correctness and feasibility are then verified with simulations. Finally, interaction experiments under fixed environment and cooperative motion are carried out, and the results demonstrate that force control for a quasi-translational FLPM can be accomplished with enough pose accuracy.","PeriodicalId":49155,"journal":{"name":"Journal of Mechanisms and Robotics-Transactions of the Asme","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135569834","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 Locusts keep their bodies moving in a straight line during the takeoff and maintain the body stable during the whole jumping with small pitching motions, ensuring both kinematic and dynamic stability to reach their intended destinations. Inspired by locusts’ jumping performance, the Stephenson II six-bar jumping mechanism is adopted to mimic the kinematic stability of locusts’ takeoff and a dynamic model is developed to analyze the impacts of the torsional spring location, the spring stiffness, and the location of the equivalent body bar centroid on the jumping performance. Furthermore, a revised eight-bar jumping mechanism is proposed to solve the difficulty in realizing dynamic stability using the six-bar mechanism, as the moments of momentum of each component around the overall centroid are positive and contribute together to the counterclockwise rotation of the jumping. The dynamic modeling shows that the mass of the equivalent tarsus bar plays an important role in realizing the dynamic stability for the eight-bar jumping mechanism. Finally, two kinds of jumping robots are designed, fabricated and tested with jumping performance recorded by high-speed cameras, which validates the impacts of the mass of the equivalent tarsus bar on the jumping stability in the eight-bar jumping mechanism.
{"title":"Locust-inspired Jumping Mechanism Design and Improvement Based on Takeoff Stability","authors":"Xiaojuan Mo, Wenjie Ge, Yifei Ren, Donglai Zhao, Dunwen Wei, Donato Romano","doi":"10.1115/1.4063406","DOIUrl":"https://doi.org/10.1115/1.4063406","url":null,"abstract":"Abstract Locusts keep their bodies moving in a straight line during the takeoff and maintain the body stable during the whole jumping with small pitching motions, ensuring both kinematic and dynamic stability to reach their intended destinations. Inspired by locusts’ jumping performance, the Stephenson II six-bar jumping mechanism is adopted to mimic the kinematic stability of locusts’ takeoff and a dynamic model is developed to analyze the impacts of the torsional spring location, the spring stiffness, and the location of the equivalent body bar centroid on the jumping performance. Furthermore, a revised eight-bar jumping mechanism is proposed to solve the difficulty in realizing dynamic stability using the six-bar mechanism, as the moments of momentum of each component around the overall centroid are positive and contribute together to the counterclockwise rotation of the jumping. The dynamic modeling shows that the mass of the equivalent tarsus bar plays an important role in realizing the dynamic stability for the eight-bar jumping mechanism. Finally, two kinds of jumping robots are designed, fabricated and tested with jumping performance recorded by high-speed cameras, which validates the impacts of the mass of the equivalent tarsus bar on the jumping stability in the eight-bar jumping mechanism.","PeriodicalId":49155,"journal":{"name":"Journal of Mechanisms and Robotics-Transactions of the Asme","volume":"183 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135944586","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 The morphing wing can enable the aircraft to maintain good flight performance in different missions or flight stages, which has enjoyed much attention in recent research. However, it is difficult to design the wing with multiple configurations and lightweight. Inspired by the origami art, a reconfigurable mechanism with a single-degree-of-freedom (single-DOF) is introduced to the morphing wing design in this paper. The bending configuration, the deployable configuration, and the configuration transformation of the reconfigurable mechanism are respectively analyzed. The lengths of some links are also optimized according to the motion requirements. Specific kinematic pairs of the reconfigurable mechanism are required to have the locking function. Therefore, a reliable “plug-in” type lockable mechanism is designed and its working performance is verified by comparing the analytical model and the finite element method model. Finally, by assembling the reconfigurable mechanism with the ribs, the reconfigurable wing which can realize the arbitrary transformation of four configurations under a single drive mode can be obtained.
{"title":"Origami-inspired design of a single-DOF reconfigurable wing with lockable mechanisms","authors":"Xiong Zhang, Xi Kang, Bing Li","doi":"10.1115/1.4063456","DOIUrl":"https://doi.org/10.1115/1.4063456","url":null,"abstract":"Abstract The morphing wing can enable the aircraft to maintain good flight performance in different missions or flight stages, which has enjoyed much attention in recent research. However, it is difficult to design the wing with multiple configurations and lightweight. Inspired by the origami art, a reconfigurable mechanism with a single-degree-of-freedom (single-DOF) is introduced to the morphing wing design in this paper. The bending configuration, the deployable configuration, and the configuration transformation of the reconfigurable mechanism are respectively analyzed. The lengths of some links are also optimized according to the motion requirements. Specific kinematic pairs of the reconfigurable mechanism are required to have the locking function. Therefore, a reliable “plug-in” type lockable mechanism is designed and its working performance is verified by comparing the analytical model and the finite element method model. Finally, by assembling the reconfigurable mechanism with the ribs, the reconfigurable wing which can realize the arbitrary transformation of four configurations under a single drive mode can be obtained.","PeriodicalId":49155,"journal":{"name":"Journal of Mechanisms and Robotics-Transactions of the Asme","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135944441","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}
Linzi Fan, Ruoqi He, Yao Chen, Shun Hu, Pooya Sareh
Abstract Deployable ring structures have been useful concepts for engineering design applications due to their smooth transformation from an initially compact configuration to a substantially larger deployed state. As a result, over the past few decades, various computational and kinematic models have been introduced to analyze the behavior of such deployable structures. Here, we propose a type of deployable ring structure designed based on a transformable concept known as the Swivel Diaphragm. In particular, the geometry of the deployable ring structure is introduced, including different structural configurations with fixed pivots and angulated beams. Then, taking a group-theoretic approach, we establish appropriate constraint equations and perform a symmetry-adapted kinematic analysis. In the next step, the mobility and self-stress states of three example structures are studied, including a simple ring structure with C3 symmetry, a C6-symmetric ring with a hexagonal Swivel Diaphragm structure, and a general Cn-symmetric ring structure with inner hoops. The usefulness and effectiveness of the utilized group-theoretic approach are examined and validated through the study of these examples. We show that the kinematic behavior of the numerical models developed in this study agrees well with the finite element results obtained using abaqus. Importantly, the illustrated motion trajectories of the reconfigurable structures demonstrate that they retain a single degree-of-freedom as well as a cyclic symmetry. Moreover, it is shown that the angulated members necessarily rotate around the fixed pivots, which could be practically desirable in designing transformable structures for various applications in engineering and architecture.
{"title":"Cyclic reconfigurability of deployable ring structures with angulated beams","authors":"Linzi Fan, Ruoqi He, Yao Chen, Shun Hu, Pooya Sareh","doi":"10.1115/1.4063408","DOIUrl":"https://doi.org/10.1115/1.4063408","url":null,"abstract":"Abstract Deployable ring structures have been useful concepts for engineering design applications due to their smooth transformation from an initially compact configuration to a substantially larger deployed state. As a result, over the past few decades, various computational and kinematic models have been introduced to analyze the behavior of such deployable structures. Here, we propose a type of deployable ring structure designed based on a transformable concept known as the Swivel Diaphragm. In particular, the geometry of the deployable ring structure is introduced, including different structural configurations with fixed pivots and angulated beams. Then, taking a group-theoretic approach, we establish appropriate constraint equations and perform a symmetry-adapted kinematic analysis. In the next step, the mobility and self-stress states of three example structures are studied, including a simple ring structure with C3 symmetry, a C6-symmetric ring with a hexagonal Swivel Diaphragm structure, and a general Cn-symmetric ring structure with inner hoops. The usefulness and effectiveness of the utilized group-theoretic approach are examined and validated through the study of these examples. We show that the kinematic behavior of the numerical models developed in this study agrees well with the finite element results obtained using abaqus. Importantly, the illustrated motion trajectories of the reconfigurable structures demonstrate that they retain a single degree-of-freedom as well as a cyclic symmetry. Moreover, it is shown that the angulated members necessarily rotate around the fixed pivots, which could be practically desirable in designing transformable structures for various applications in engineering and architecture.","PeriodicalId":49155,"journal":{"name":"Journal of Mechanisms and Robotics-Transactions of the Asme","volume":"80 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":"136077388","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}
Bing Chen, Xiang Ni, Bin Zi, Qingsong Xu, Jun Qian
Abstract This paper illustrates the design and testing of an upper-body exoskeleton for the assistance of individuals with load-lifting and load-carrying tasks, and the provided assistive force can well match with the force required by the human. First, the biomechanics of the human lumbar during the squat lifting of an object is described. Next, the modeling of the exoskeleton is introduced. Additionally, the hardware design of the exoskeleton is presented. The exoskeleton is mainly composed of a back-assist mechanism and an upper extremity labor-saving mechanism, which can assist the wearer’s lumbar during the squat lifting of an object and assist the wearer’s arms to carry an object during walking, respectively. Finally, experiments are conducted to evaluate the performance of the developed upper-body exoskeleton. The experimental results demonstrate that the exoskeleton has the potential to provide assistance for individuals with manual handling tasks. An average assistive force of 44.8 N can be provided for the wearer to lift a 10-kg object. During the squat lifting of the 10-kg object, reductions of 31.86% and 28.30% of the average muscle activities of the wearer’s lumbar erector spinae and thoracic erector spinae are observed, respectively. In addition, a reduction of 23.78% of the average muscle activity of the wearer’s biceps brachii is observed during walking while carrying the 10-kg object.
{"title":"Design and Implementation of Upper-Body Exoskeleton for Assistance of Individuals With Manual Handling Tasks","authors":"Bing Chen, Xiang Ni, Bin Zi, Qingsong Xu, Jun Qian","doi":"10.1115/1.4063455","DOIUrl":"https://doi.org/10.1115/1.4063455","url":null,"abstract":"Abstract This paper illustrates the design and testing of an upper-body exoskeleton for the assistance of individuals with load-lifting and load-carrying tasks, and the provided assistive force can well match with the force required by the human. First, the biomechanics of the human lumbar during the squat lifting of an object is described. Next, the modeling of the exoskeleton is introduced. Additionally, the hardware design of the exoskeleton is presented. The exoskeleton is mainly composed of a back-assist mechanism and an upper extremity labor-saving mechanism, which can assist the wearer’s lumbar during the squat lifting of an object and assist the wearer’s arms to carry an object during walking, respectively. Finally, experiments are conducted to evaluate the performance of the developed upper-body exoskeleton. The experimental results demonstrate that the exoskeleton has the potential to provide assistance for individuals with manual handling tasks. An average assistive force of 44.8 N can be provided for the wearer to lift a 10-kg object. During the squat lifting of the 10-kg object, reductions of 31.86% and 28.30% of the average muscle activities of the wearer’s lumbar erector spinae and thoracic erector spinae are observed, respectively. In addition, a reduction of 23.78% of the average muscle activity of the wearer’s biceps brachii is observed during walking while carrying the 10-kg object.","PeriodicalId":49155,"journal":{"name":"Journal of Mechanisms and Robotics-Transactions of the Asme","volume":"1 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":"136078563","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, Zirui Jia, Sen Qian, Daoming Wang, Xiang Yu, Xuchang Liu
Abstract The notched continuum mechanism is particularly suitable for natural orifice transluminal surgery benefiting from its small size and hollow structure. However, the widely used kinematic model based on constant curvature assumption does not reveal the actual deformation of the continuum mechanism, and its control accuracy is unstable, while the general mechanics model has the problem that the tension of the distal driving cable is difficult to measure. In this paper, a nonconstant curvature static model for a bidirectional V-shaped notched continuum mechanism is presented. The deformation of each part of the continuum mechanism from the distal end to the proximal end is analyzed in turn. The tension loss of the driving cable caused by the contact with the continuum mechanism is modeled using the capstan equation. The recursive equation between the deformation of each part of the continuum mechanism from the proximal end is derived, which can be solved numerically. The bending state of the continuum mechanism can then be estimated when only the tension of the proximal flexible cable is known. The model is experimentally verified by driving the continuum mechanism to move at a very low speed. The experiment results show that the estimation effect of the proposed model is significantly improved compared with that of the constant curvature model.
{"title":"An Improved Static Model for Bidirectional Notched Continuum Robot Considering the Cable-tension Loss","authors":"Zhengyu Wang, Zirui Jia, Sen Qian, Daoming Wang, Xiang Yu, Xuchang Liu","doi":"10.1115/1.4063454","DOIUrl":"https://doi.org/10.1115/1.4063454","url":null,"abstract":"Abstract The notched continuum mechanism is particularly suitable for natural orifice transluminal surgery benefiting from its small size and hollow structure. However, the widely used kinematic model based on constant curvature assumption does not reveal the actual deformation of the continuum mechanism, and its control accuracy is unstable, while the general mechanics model has the problem that the tension of the distal driving cable is difficult to measure. In this paper, a nonconstant curvature static model for a bidirectional V-shaped notched continuum mechanism is presented. The deformation of each part of the continuum mechanism from the distal end to the proximal end is analyzed in turn. The tension loss of the driving cable caused by the contact with the continuum mechanism is modeled using the capstan equation. The recursive equation between the deformation of each part of the continuum mechanism from the proximal end is derived, which can be solved numerically. The bending state of the continuum mechanism can then be estimated when only the tension of the proximal flexible cable is known. The model is experimentally verified by driving the continuum mechanism to move at a very low speed. The experiment results show that the estimation effect of the proposed model is significantly improved compared with that of the constant curvature model.","PeriodicalId":49155,"journal":{"name":"Journal of Mechanisms and Robotics-Transactions of the Asme","volume":"38 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":"136078564","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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