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dimensional synthesis of a 3-DOF Parallel Manipulator with Full Circle Rotation

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Chinese Journal of Mechanical Engineering 2015年第4期28卷 830-840页

作者： NI Yanbing WU Nan ZHONG Xueyong ZHANG Biao School of Mechanical Engineering Tianjin University FAW Jiefang Automotive Company LtdAxle Filiale

Parallel robots are widely used in the academic and industrial fields. In spite of the numerous achievements in the design and dimensional synthesis of the low-mobility parallel robots, few research efforts are directed towards the asymmetric 3-DOF parallel robots whose end-effector can realize 2 translational and 1 rotational（2T1R） motion. In order to develop a manipulator with the capability of full circle rotation to enlarge the workspace, a new 2T1 R parallel mechanism is proposed. The modeling approach and kinematic analysis of this proposed mechanism are investigated. Using the method of vector analysis, the inverse kinematic equations are established. This is followed by a vigorous proof that this mechanism attains an annular workspace through its circular rotation and 2 dimensional translations. Taking the first order perturbation of the kinematic equations, the error Jacobian matrix which represents the mapping relationship between the error sources of geometric parameters and the end-effector position errors is derived. With consideration of the constraint conditions of pressure angles and feasible workspace, the dimensional synthesis is conducted with a goal to minimize the global comprehensive performance index. The dimension parameters making the mechanism to have optimal error mapping and kinematic performance are obtained through the optimization algorithm. All these research achievements lay the foundation for the prototype building of such kind of parallel robots.

关键词： parallel manipulator kinematic analysis dimensional synthesis

dimensional synthesis of a novel 5-DOF reconfigurable hybrid perfusion manipulator for large-scale spherical honeycomb perfusion

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Frontiers of Mechanical Engineering 2021年第1期16卷 46-60页

作者： Hui YANG Hairong FANG Yuefa FANG Xiangyun LI School of Mechanical Engineering Beijing Jiaotong UniversityBeijing 100044China School of Mechanical Engineering Southwest Jiaotong UniversityChengdu 610031China

A novel hybrid perfusion manipulator(HPM)with five degrees of freedom(DOFs)is introduced by combining the 5PUS-PRPU(P,R,U and S represent prismatic,revolute,universal and spherical joint,respectively)parallel mechanism with the 5PRR reconfigurable base to enhance the perfusion efficiency of the large-scale spherical honeycomb thermal protection *** study mainly presents the dimensional synthesis of the proposed ***,the inverse kinematics,including the analytic expression of the rotation angles of the U joint in the PUS limb,is obtained,and mobility analysis is conducted based on screw *** Jacobian matrix of 5PUS-PRPU is also determined with screw theory and used for the establishment of the objective ***,a global and comprehensive objective function(GCOF)is proposed to represent the Jacobian matrix’s condition *** the genetic algorithm,dimensional synthesis is conducted by minimizing GCOF subject to the given variable *** values of the designed variables corresponding to different configurations of the reconfigurable base are then ***,the optimal structure parameters of the proposed 5-DOF HPM are *** show that the HPM with the optimized parameters has an enlarged orientation workspace,and the maximum angle of the reconfigurable base is decreased,which is conducive to improving the overall stiffness of HPM.

关键词： 5-DOF hybrid manipulator reconfigurable base large workspace dimensional synthesis optimal design

Geometric Design-based dimensional synthesis of a Novel Metamorphic Multi-fingered Hand with Maximal Workspace

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Chinese Journal of Mechanical Engineering 2021年第3期34卷 211-225页

作者： Wei An Jun Wei Xiaoyu Lu Jian S.Dai Yanzeng Li MOE Key Laboratory for Mechanism Theory and Equipment Design International Centre for Advanced Mechanisms and RoboticsTianjin UniversityTianjinChina Advanced Kinematics and Reconfigurable Robotics Lab School of Natural and Mathematical SciencesKing’s College LondonLondonUK Rutgers The State University of New JerseyNew BrunswickNew JerseyUSA

Current research on robotic dexterous hands mainly focuses on designing new finger and palm structures,as well as developing smarter control *** the dimensional synthesis of dexterous hands with traditional rigid palms has been carried out,research on the dimensional synthesis of dexterous hands with metamorphic palms remains *** study investigated the dimensional synthesis of a palm of a novel metamorphic multi-fingered hand,and explored the geometric design for maximizing the precision manipulation *** indexes were used to value the workspace of the metamorphic hand,and the best proportions between the five links of the palm to obtain the optimal workspace of the metamorphic hand were *** on the fixed total length of the palm member,four nondimensional design parameters that determine the size of the palm were introduced;through the discretization method,the influence of the four design parameters on the workspace of the metamorphic hand with full-actuated fingers and under-actuated fingers was *** on the analysis of the metamorphic multi-fingered hand,the symmetrical structure of the palm was designed,resulting in the largest workspace of the multi-fingered hand,and proved that the metamorphic palm has a massive upgrade for the workspace of underactuated *** research contributed to the dimensional synthesis of metamorphic dexterous hands,with practical significance for the design and optimization of novel metamorphic hands.

关键词： Metamorphic hands dimensional synthesis Maximal workspace Discretization

dimensional synthesis Design of Novel Parallel Machine Tool

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Tsinghua Science and Technology 2002年第3期7卷 258-262页

作者：汪劲松唐晓强段广洪尹文生 Manufacturing Engineering Institute School of Mechanical Engineering Tsinghua University Beijing 100084 China

This paper presents dimensional synthesis design theory for a novel planar 3-DOF (degrees of freedom) parallel machine tool. Closed-form solutions are developed for both the inverse and direct kinematics. The formulation of the dexterity and the definitions of the theoretical workspace and the valid workspace are used to analyze the effects of the design parameters on the dexterity and workspace. The analysis results are used to propose an approach to satisfy the platform motion requirement while realizing orientation capability, dexterity and valid workspace. A design example is given to illustrate the effectiveness of this approach.

关键词： dimensional synthesis design parallel machine tool

synthesis of Stephenson in Six-Link Mechanism for Function Generation Using an Improved Homotopy Method

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Journal of Southwest Jiaotong University(English Edition) 2002年第2期10卷 161-166页

作者： Li Li(李立) Chen Yong(陈永) School of Mechanical Engineering Southwest Jiaotong University Chengdu 610031 China School of Mechanical Engineering Southwest Jiaotong University Chengdu 610031 China

This paper presents solutions to the function generation problems of Stephenson Ⅲ six-link mechanism with the maximum precision positions for the first time using homotopy method with an improved path-tracking scheme. The new path-tracking scheme is based on the characteristics of the zero sets of homotopy function for polynomial mapping and thus the tracking speed is dramatically increased.

关键词： homotopy function mechanisms dimensional synthesis polynomial mapping