三平移机构设计与运动学符号解及性能评价  

Design,Kinematic Symbolic Solution and Performance Evaluation of New Three Translation Mechanism

作　　者：沈惠平[1] 吉昊 许正骁 杨廷力[1] SHEN Huiping;JI Hao;XU Zhengxiao;YANG Tingli(Research Center for Advanced Mechanism Theory, Changzhou University, Changzhou 213016, China)

机构地区：[1]常州大学现代机构学研究中心,常州213016

出　　处：《农业机械学报》2020年第9期397-407,共11页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家自然科学基金项目(51975062、51475505、51375062)。

摘　　要：根据基于方位特征(POC)方程的并联机构拓扑结构设计理论和方法,设计一种具有正向位置符号解且具有部分运动解耦性的新型三平移(3T)并联机构。首先,对其进行拓扑特性分析,得到方位特征集(POC)、自由度(DOF)、耦合度(κ)等主要拓扑特征值;其次,根据提出的基于拓扑特征的正向运动学建模原理,求出机构的正向位置符号解;根据推导的逆解公式,求解该机构的工作空间;基于旋量理论求解各支链传递力旋量与输出运动旋量,得到机构运动/力传递性能指标,并分析相关的奇异位型;最后,利用局部传递指标评价了机构距离奇异位型的远近。According to the topology design theory and method of parallel mechanism(PM)based on position and orientation characteristic(POC)equations,a new type of three translation(3T)PM with symbolic positive position solutions and partial motion decoupling was designed.Firstly,its topological characteristics were analyzed,and the values of its main topological features,such as POC,DOF andκ,were obtained.Secondly,the symbolic positive position solutions of the PM were obtained according to the positive kinematics modeling principle based on topological characteristics proposed by the authors.The correctness of the positive position solution was verified by the numerical model.The inverse position solution was solved and verified,The workspace of the PM was solved based on the inverse solution formula.Furthermore,the screw theory was used to solve the transmission wrench screw and the output twist screw of each branch chain.The kinematic/force transmission performance index of the mechanism were solved.The curves of input transmission index(LTI),output transmission index(OTI)and local transmission index were drawn by Matlab,According to the expression of the reciprocal product of the input twist screw and the transmission wrench screw,the expression of the output twist screw and the transmission wrench screw,and linearly independent numbers of three constraint wrench screw,the singular configuration of the mechanism was analyzed.Finally,according to the curve of LTI,the distance between each point in the workspace and the singular configuration was evaluated.

关 键 词：三平移 解析正解 工作空间 性能指标 奇异分析 

分 类 号：TH112[机械工程—机械设计及理论]