Flexure hinges are joints typically used in the construction of compliant mechanisms, especially when small dimensions do not allow for conventional mechanical devices. In this paper, a closed-form solution is proposed for a nonlinear stiffness model used to describe the static displacements obtained on a flexure hinge of elementary geometry as a function of applied loads. A comparison with the most widely used linear model demonstrates the effectiveness of the proposed nonlinear approach, high- lighting the advantages in its use and its scope of application. The results are verified by Finite Element (FE) simulations, taken as a reference of the actual behavior assumed for the joints studied.
{"title":"A Dimensionless Large Displacement Model for Flexure Hinges of Elliptical Geometry","authors":"Simir Moschini, Matteo-Claudio Palpacelli","doi":"10.1115/1.4064416","DOIUrl":"https://doi.org/10.1115/1.4064416","url":null,"abstract":"\u0000 Flexure hinges are joints typically used in the construction of compliant mechanisms, especially when small dimensions do not allow for conventional mechanical devices. In this paper, a closed-form solution is proposed for a nonlinear stiffness model used to describe the static displacements obtained on a flexure hinge of elementary geometry as a function of applied loads. A comparison with the most widely used linear model demonstrates the effectiveness of the proposed nonlinear approach, high- lighting the advantages in its use and its scope of application. The results are verified by Finite Element (FE) simulations, taken as a reference of the actual behavior assumed for the joints studied.","PeriodicalId":508172,"journal":{"name":"Journal of Mechanisms and Robotics","volume":"14 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139386688","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}
This paper proposes a novel synthesis method of constructing plane-space switching mechanisms based on the symmetric plane of the regular prism. First, the structure equation and motion characteristic of plane-symmetric eight-bar linkage are presented. Then the plane-symmetric seven-bar linkage and rhombic Bricard linkage are obtained by locking the joint of eight-bar linkage. Four types of plane-space switching mechanisms are constructed based on the synthesis method and switching linkage units. These switching mechanisms can expand completely into planar configurations and fold completely into spatial configurations. Subsequently, the kinematics of the coupled branch chain is analyzed, through which the folded and contractive characteristics of the mechanism are revealed. Then the concept of distributed circle of joints is proposed, and the enveloping performance of the mechanism is approximately analyzed. This paper provides a new idea and synthesis method for designing new deployable mechanisms.
{"title":"Synthesis and analysis of plane-space switching mechanisms based on a plane-symmetric eight-bar linkage","authors":"J.F. Liu, Haoran Zuo, Huafeng Ding, Meng Li","doi":"10.1115/1.4064333","DOIUrl":"https://doi.org/10.1115/1.4064333","url":null,"abstract":"This paper proposes a novel synthesis method of constructing plane-space switching mechanisms based on the symmetric plane of the regular prism. First, the structure equation and motion characteristic of plane-symmetric eight-bar linkage are presented. Then the plane-symmetric seven-bar linkage and rhombic Bricard linkage are obtained by locking the joint of eight-bar linkage. Four types of plane-space switching mechanisms are constructed based on the synthesis method and switching linkage units. These switching mechanisms can expand completely into planar configurations and fold completely into spatial configurations. Subsequently, the kinematics of the coupled branch chain is analyzed, through which the folded and contractive characteristics of the mechanism are revealed. Then the concept of distributed circle of joints is proposed, and the enveloping performance of the mechanism is approximately analyzed. This paper provides a new idea and synthesis method for designing new deployable mechanisms.","PeriodicalId":508172,"journal":{"name":"Journal of Mechanisms and Robotics","volume":"114 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139169184","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}
Physical human-robot interfaces (pHRI) enabled the robots to work alongside the human workers complying with the regulations set for physical human-robot interaction systems. A variety of actuation systems named variable stiffness/impedance actuators (VSAs) are configured to be used in these systems' design. Recently, we introduced a new continuously variable transmission (CVT) mechanism as an alternative solution in configuring VSAs for pHRI. The optimization of this CVT has significant importance to enhance its application area and to detect the limitations of the system. Thus, in this paper, we present a design optimization approach (an adjustment strategy) for this system based on the design goals, desired force and minimization of the size of the system. To implement such design goals, the static force analysis of the CVT is performed and validated. Furthermore, the fabrication of the optimized prototype is presented, and the experimental verification is performed considering the requirements of VSAs: independent position and stiffness variation, and shock absorbing. Finally, the system is calibrated to display 6 N continuous output force throughout its transmission variation range.
物理人机界面（pHRI）使机器人能够与人类工人一起工作，符合物理人机交互系统的规定。在这些系统的设计中，配置了各种名为可变刚度/阻抗致动器（VSA）的执行系统。最近，我们引入了一种新的无级变速器（CVT）机制，作为为 pHRI 配置 VSA 的替代解决方案。对这种无级变速器进行优化对提高其应用范围和检测系统的局限性具有重要意义。因此，在本文中，我们根据设计目标、所需的力和最小化系统尺寸，为该系统提出了一种设计优化方法（调整策略）。为了实现这些设计目标，我们对无级变速器进行了静态力分析并进行了验证。此外，还介绍了优化原型的制造过程，并根据 VSA 的要求进行了实验验证：独立的位置和刚度变化以及减震。最后，对系统进行了校准，使其在整个传动变化范围内显示 6 N 的连续输出力。
{"title":"A CVT-based Variable Stiffness Actuator for pHRI: Design Optimization and Performance Verification","authors":"Emir Mobedi, M. Dede","doi":"10.1115/1.4064280","DOIUrl":"https://doi.org/10.1115/1.4064280","url":null,"abstract":"Physical human-robot interfaces (pHRI) enabled the robots to work alongside the human workers complying with the regulations set for physical human-robot interaction systems. A variety of actuation systems named variable stiffness/impedance actuators (VSAs) are configured to be used in these systems' design. Recently, we introduced a new continuously variable transmission (CVT) mechanism as an alternative solution in configuring VSAs for pHRI. The optimization of this CVT has significant importance to enhance its application area and to detect the limitations of the system. Thus, in this paper, we present a design optimization approach (an adjustment strategy) for this system based on the design goals, desired force and minimization of the size of the system. To implement such design goals, the static force analysis of the CVT is performed and validated. Furthermore, the fabrication of the optimized prototype is presented, and the experimental verification is performed considering the requirements of VSAs: independent position and stiffness variation, and shock absorbing. Finally, the system is calibrated to display 6 N continuous output force throughout its transmission variation range.","PeriodicalId":508172,"journal":{"name":"Journal of Mechanisms and Robotics","volume":"43 15","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139179361","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}
This paper presents the design, optimization, control, and experimental evaluation of a novel compact exoskeleton glove aiming to assist patients with brachial plexus injuries in grasping daily used objects. The finger mechanism is based on a rigid coupling hybrid mechanism (RCHM) concept, which utilizes a serially connected rack-and-pinion mechanism and an offset slider-crank mechanism to couple the motions of different finger joints. The glove dimensions are synthesized based on the natural grasping motion of human hands. To better control the glove and enhance the grasping capabilities, a simulation environment was developed and reinforcement learning techniques were applied. This learning-based control trained an agent to perform different grasp types with appropriate force. The trained agent was then applied in real-world experiments with the developed exoskeleton glove. The results validated the effectiveness of the mechanical design and the real-time self-adjustable control policy, which demonstrated the glove's functionality and capability to grasp various objects relevant to activities of daily living (ADLs)
{"title":"Development of a Novel Compact Robotic Exoskeleton Glove with Reinforcement Learning Control","authors":"Wenda Xu, Yunfei Guo, Yujiong Liu, Pinhas Ben-Tzvi","doi":"10.1115/1.4064283","DOIUrl":"https://doi.org/10.1115/1.4064283","url":null,"abstract":"This paper presents the design, optimization, control, and experimental evaluation of a novel compact exoskeleton glove aiming to assist patients with brachial plexus injuries in grasping daily used objects. The finger mechanism is based on a rigid coupling hybrid mechanism (RCHM) concept, which utilizes a serially connected rack-and-pinion mechanism and an offset slider-crank mechanism to couple the motions of different finger joints. The glove dimensions are synthesized based on the natural grasping motion of human hands. To better control the glove and enhance the grasping capabilities, a simulation environment was developed and reinforcement learning techniques were applied. This learning-based control trained an agent to perform different grasp types with appropriate force. The trained agent was then applied in real-world experiments with the developed exoskeleton glove. The results validated the effectiveness of the mechanical design and the real-time self-adjustable control policy, which demonstrated the glove's functionality and capability to grasp various objects relevant to activities of daily living (ADLs)","PeriodicalId":508172,"journal":{"name":"Journal of Mechanisms and Robotics","volume":"60 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139180358","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}
Seth Donahue, Trevor Kingsbury, Kota Takahshi, Matty J. Major
Modelling the non-linear dynamics of prosthetic feet is an important tool for linking prosthesis mechanical properties to end-user outcomes. There has been a renewed interest in data-driven modelling of dynamical systems, with the development of the Extended Dynamic Mode Decomposition with control (eDMDc), and the Sparse Identification of Non-Linear Dynamics with Control (SINDYc). These algorithms do not require prior information about the system, including mechanical configuration, and are data-driven. The aim of this study was to assess feasibility and accuracy of applying these data-driven algorithms to model prosthesis non-linear load response dynamics. Different combinations of a dynamic response foot, a hydraulic ankle unit, and three shock absorbing pylons of varying resistance were tested loaded and unloaded at three orientations reflecting critical positions during the stance phase of walking. We tested two different data-driven algorithms, the eDMDc, with two different kernels, and the SINDYc, which regresses the coefficients for a non-linear ordinary differential equation. Each algorithm was able to model the non-linear prosthesis dynamics, but the SINDYc outperformed the eDMDc methods with a root mean square error across orientations < 1.50 mm and a maximum error in peak displacement of 1.28 mm or 4% relative error. From the estimated SINDYc governing equation of the system dynamics, we were able to simulate different mechanical behavior by systematically varying parameter values, which offers a novel foundation for designing, controlling, and classifying prosthetic systems ultimately aimed at improving prosthesis user outcomes.
{"title":"Data-Driven Modelling of the Non-Linear Dynamics of Passive Lower-Limb Prosthetic Systems","authors":"Seth Donahue, Trevor Kingsbury, Kota Takahshi, Matty J. Major","doi":"10.1115/1.4064279","DOIUrl":"https://doi.org/10.1115/1.4064279","url":null,"abstract":"Modelling the non-linear dynamics of prosthetic feet is an important tool for linking prosthesis mechanical properties to end-user outcomes. There has been a renewed interest in data-driven modelling of dynamical systems, with the development of the Extended Dynamic Mode Decomposition with control (eDMDc), and the Sparse Identification of Non-Linear Dynamics with Control (SINDYc). These algorithms do not require prior information about the system, including mechanical configuration, and are data-driven. The aim of this study was to assess feasibility and accuracy of applying these data-driven algorithms to model prosthesis non-linear load response dynamics. Different combinations of a dynamic response foot, a hydraulic ankle unit, and three shock absorbing pylons of varying resistance were tested loaded and unloaded at three orientations reflecting critical positions during the stance phase of walking. We tested two different data-driven algorithms, the eDMDc, with two different kernels, and the SINDYc, which regresses the coefficients for a non-linear ordinary differential equation. Each algorithm was able to model the non-linear prosthesis dynamics, but the SINDYc outperformed the eDMDc methods with a root mean square error across orientations < 1.50 mm and a maximum error in peak displacement of 1.28 mm or 4% relative error. From the estimated SINDYc governing equation of the system dynamics, we were able to simulate different mechanical behavior by systematically varying parameter values, which offers a novel foundation for designing, controlling, and classifying prosthetic systems ultimately aimed at improving prosthesis user outcomes.","PeriodicalId":508172,"journal":{"name":"Journal of Mechanisms and Robotics","volume":"150 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139179813","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}
The demand for robots capable of performing collaborative tasks requiring interactions with the environment is on the rise. Safe interactions with the environment require attributes such as high dexterity and compliance around obstacles, while still maintaining the requisite stiffness levels for payload manipulation. Such attributes are inherent to biological musculoskeletal systems. Motivated by this realization, this paper proposes a cable-actuated spatial joint with variable stiffness, inspired by the tensegrity principles found in biological musculoskeletal systems. The paper provides a detailed analysis of the joint's mobility and mechanism kinematics. Based on the limits of the actuation forces, the paper also presents the wrench-feasible workspace of the joint. The paper also outlines the conditions that the cable actuation forces must satisfy to maintain the static equilibrium of the joint. The stiffness modelling presented in this work demonstrates the modulation of stiffness bounds as a function of cable actuation forces. Furthermore, the stiffness modulation as a function of the geometrical parameters is also presented.
{"title":"Kinetostatic analysis of a spatial cable-actuated variable stiffness joint","authors":"Isaac John, Santhakumar Mohan, Philippe Wenger","doi":"10.1115/1.4064254","DOIUrl":"https://doi.org/10.1115/1.4064254","url":null,"abstract":"The demand for robots capable of performing collaborative tasks requiring interactions with the environment is on the rise. Safe interactions with the environment require attributes such as high dexterity and compliance around obstacles, while still maintaining the requisite stiffness levels for payload manipulation. Such attributes are inherent to biological musculoskeletal systems. Motivated by this realization, this paper proposes a cable-actuated spatial joint with variable stiffness, inspired by the tensegrity principles found in biological musculoskeletal systems. The paper provides a detailed analysis of the joint's mobility and mechanism kinematics. Based on the limits of the actuation forces, the paper also presents the wrench-feasible workspace of the joint. The paper also outlines the conditions that the cable actuation forces must satisfy to maintain the static equilibrium of the joint. The stiffness modelling presented in this work demonstrates the modulation of stiffness bounds as a function of cable actuation forces. Furthermore, the stiffness modulation as a function of the geometrical parameters is also presented.","PeriodicalId":508172,"journal":{"name":"Journal of Mechanisms and Robotics","volume":"7 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139182980","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}
Zhumadil Baigunchekov, M. Laribi, Giuseppe Carbone, R. Kaiyrov, Serik Tolenov, Nurdaulet Dosmagambet
This paper studies a structural-parametric synthesis of the four-bar and Stephenson II, Stephenson III A, Stephenson III B six-bar function generators. Four-bar function generator is formed by connecting two coordinate systems with given angles of rotation using a negative closing kinematic chain (CKC) of the RR type. Six-bar function generators are formed by connecting two coordinate systems using two CKCs: a passive CKC of the RRR type and a negative CKC of the RR type. The negative CKC of the RR type imposes one geometrical constraint to the relative motion of the links, and its geometric parameters are defined by least-square approximation. Passive CKC of the RRR type does not impose a geometrical constraint, and the geometric parameters of its links are varied to satisfy the geometrical constraint of the negative CKC. Numerical results of the four-bar and six-bar function generators parametric synthesis are presented.
本文研究了四杆函数发生器和史蒂芬森 II、史蒂芬森 III A、史蒂芬森 III B 六杆函数发生器的结构参数合成。四杆函数发生器是通过使用 RR 型负闭合运动学链（CKC）连接两个给定旋转角度的坐标系而形成的。六杆函数发生器是通过两个 CKC（RRR 型被动 CKC 和 RR 型负 CKC）连接两个坐标系而形成的。RR 型负 CKC 对链接的相对运动施加一个几何约束，其几何参数通过最小二乘法近似确定。RRR 型被动 CKC 不施加几何约束，其链路的几何参数可通过改变来满足负 CKC 的几何约束。介绍了四杆和六杆函数发生器参数合成的数值结果。
{"title":"Structural-Parametric Synthesis of the Planar Four-Bar and Six-Bar Function Generators with Revolute Joints","authors":"Zhumadil Baigunchekov, M. Laribi, Giuseppe Carbone, R. Kaiyrov, Serik Tolenov, Nurdaulet Dosmagambet","doi":"10.1115/1.4064253","DOIUrl":"https://doi.org/10.1115/1.4064253","url":null,"abstract":"This paper studies a structural-parametric synthesis of the four-bar and Stephenson II, Stephenson III A, Stephenson III B six-bar function generators. Four-bar function generator is formed by connecting two coordinate systems with given angles of rotation using a negative closing kinematic chain (CKC) of the RR type. Six-bar function generators are formed by connecting two coordinate systems using two CKCs: a passive CKC of the RRR type and a negative CKC of the RR type. The negative CKC of the RR type imposes one geometrical constraint to the relative motion of the links, and its geometric parameters are defined by least-square approximation. Passive CKC of the RRR type does not impose a geometrical constraint, and the geometric parameters of its links are varied to satisfy the geometrical constraint of the negative CKC. Numerical results of the four-bar and six-bar function generators parametric synthesis are presented.","PeriodicalId":508172,"journal":{"name":"Journal of Mechanisms and Robotics","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139182911","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}
Paulo R G Kurka, Victor Paiva, Luis Silva-Teixeira, Paola G Ramos, J. Izuka
Most studies regarding models of tensegrity systems miss the possibility of large static deformations or provide elaborate and lengthy solutions to determine the system dynamics. Contrarily, this work presents a straightforward methodology to find the dynamic characteristics of a guyed tensegrity beam structure, allowing the application of vibration control strategies in conditions of large deformations. The methodology is based on a low order, adaptive, nonlinear finite element model with pre-stressed components. The method is applied to numerical and experimental models of a class 2 tensegrity structure with a high length-to-width aspect ratio. Image processing and accelerometer data are combined to extract the experimental natural frequencies of the structure, which are compared to numerical results. Prony's method is applied to estimate damping.
{"title":"A dynamical model for the control of a guyed tensegrity beam under large displacements","authors":"Paulo R G Kurka, Victor Paiva, Luis Silva-Teixeira, Paola G Ramos, J. Izuka","doi":"10.1115/1.4064259","DOIUrl":"https://doi.org/10.1115/1.4064259","url":null,"abstract":"Most studies regarding models of tensegrity systems miss the possibility of large static deformations or provide elaborate and lengthy solutions to determine the system dynamics. Contrarily, this work presents a straightforward methodology to find the dynamic characteristics of a guyed tensegrity beam structure, allowing the application of vibration control strategies in conditions of large deformations. The methodology is based on a low order, adaptive, nonlinear finite element model with pre-stressed components. The method is applied to numerical and experimental models of a class 2 tensegrity structure with a high length-to-width aspect ratio. Image processing and accelerometer data are combined to extract the experimental natural frequencies of the structure, which are compared to numerical results. Prony's method is applied to estimate damping.","PeriodicalId":508172,"journal":{"name":"Journal of Mechanisms and Robotics","volume":"38 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139182895","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}
The paper is an extension of the original research contained in the paper “Constant Force Spring System with a Spiral” by Richard B. Hetnarski, published in the Journal of Mechanisms and Robotics, vol. 12, December, 2020. The topic of that paper is the introduction and description of a new mechanism which allows to transform the linearly changing force exerted by a helical spring into a constant force. The most important part of the system is a new spiral of which the differential equation was derived and was solved, and all this is published in that previous paper. That paper contains the detailed description of the theory of the mechanism and the analysisi of its operation. There are also provided examples of a few possible applications. A physical model of the system was built, and its testing showed the system works in agreement with the theory. However, the system is not completely accurate, that is, the force Fo remains not entirely constant during winding/unwinding of the cord. This inaccuracy is discussed and evaluated in depth by analytical and numerical methods, and the way for it to be decreased or eliminated is described. The present paper, together with the previous paper, constitute the full presentation of the mechanism and should not be separated one from the other. Since the present paper is a continuation of the previous paper, please study the paper by Hetnarski [1], before reading the present paper.
本文是对理查德-B-赫特纳尔斯基（Richard B. Hetnarski）发表于《机械与机器人学杂志》（Journal of Mechanisms and Robotics）2020 年 12 月第 12 卷的论文 "螺旋恒力弹簧系统"（Constant Force Spring System with a Spiral）中的原始研究的扩展。该论文的主题是介绍和描述一种新的机械装置，它可以将螺旋弹簧施加的线性变化力转换为恒定力。该系统最重要的部分是一个新的螺旋，其微分方程已经推导并求解，所有这一切都发表在之前的论文中。该论文详细描述了该机构的理论及其运行分析。此外，还提供了一些可能的应用实例。该系统的物理模型已经建成，其测试表明该系统的工作原理与理论相符。但是，该系统并不完全准确，也就是说，在绕线/放线过程中，力 Fo 并不完全恒定。本文通过分析和数值方法对这种不准确性进行了深入讨论和评估，并介绍了减少或消除这种不准确性的方法。本论文与前一篇论文共同构成了对该机制的完整介绍，不应割裂开来。由于本文是前一篇论文的延续，因此在阅读本文之前，请先阅读赫特纳尔斯基的论文[1]。
{"title":"Constant Force Spring System with a Spiral – Part 2: Accuracy assessment","authors":"Vittorio Zampoli, Richard Hetnarski","doi":"10.1115/1.4064130","DOIUrl":"https://doi.org/10.1115/1.4064130","url":null,"abstract":"The paper is an extension of the original research contained in the paper “Constant Force Spring System with a Spiral” by Richard B. Hetnarski, published in the Journal of Mechanisms and Robotics, vol. 12, December, 2020. The topic of that paper is the introduction and description of a new mechanism which allows to transform the linearly changing force exerted by a helical spring into a constant force. The most important part of the system is a new spiral of which the differential equation was derived and was solved, and all this is published in that previous paper. That paper contains the detailed description of the theory of the mechanism and the analysisi of its operation. There are also provided examples of a few possible applications. A physical model of the system was built, and its testing showed the system works in agreement with the theory. However, the system is not completely accurate, that is, the force Fo remains not entirely constant during winding/unwinding of the cord. This inaccuracy is discussed and evaluated in depth by analytical and numerical methods, and the way for it to be decreased or eliminated is described. The present paper, together with the previous paper, constitute the full presentation of the mechanism and should not be separated one from the other. Since the present paper is a continuation of the previous paper, please study the paper by Hetnarski [1], before reading the present paper.","PeriodicalId":508172,"journal":{"name":"Journal of Mechanisms and Robotics","volume":"81 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139242997","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}
This paper gives an exact theory in Euclidean space for studying the static stability of planar rigid systems held by one or more frictional and frictionless contacts under gravity. Static stability analysis deals with determining the feasible locations of the Centre of gravity (CG) which ensure stability. The analysis is performed here in two steps- finding the equilibrium region and finding the stability region as a subset of the equilibrium region. The stability region is determined through the analytical treatment of an elegant geometric characterization. These results are also verified through elegant geometric reasoning based on curvature theory in-plane kinematics. In the end, stability analyses of some physical systems containing generic contacting curves are il- lustrated and the results are presented with physical interpretations.
{"title":"Static Stability of Planar Contacting Systems: Analytical Treatment in Euclidean Space","authors":"A. Dan, Rama Krishna K, Subir Kumar Saha","doi":"10.1115/1.4064065","DOIUrl":"https://doi.org/10.1115/1.4064065","url":null,"abstract":"This paper gives an exact theory in Euclidean space for studying the static stability of planar rigid systems held by one or more frictional and frictionless contacts under gravity. Static stability analysis deals with determining the feasible locations of the Centre of gravity (CG) which ensure stability. The analysis is performed here in two steps- finding the equilibrium region and finding the stability region as a subset of the equilibrium region. The stability region is determined through the analytical treatment of an elegant geometric characterization. These results are also verified through elegant geometric reasoning based on curvature theory in-plane kinematics. In the end, stability analyses of some physical systems containing generic contacting curves are il- lustrated and the results are presented with physical interpretations.","PeriodicalId":508172,"journal":{"name":"Journal of Mechanisms and Robotics","volume":"15 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139267361","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：