同构支链H4并联机构的奇异性分析  

Singularity Analysis of the H4 Parallel Mechanisms with Isomorphic Sub-chains

作　　者：方斌[1] 李剑锋[1] 卿建喜[1] 

机构地区：[1]北京工业大学机械工程及应用电子技术学院,北京100124

出　　处：《机械工程学报》2010年第21期42-47,共6页Journal of Mechanical Engineering

基　　金：北京市重点实验室开放基金资助项目(JH001011200801)

摘　　要：H4机构对应于一组具有良好动态特性的并联机构,其动平台中心构件有3移动自由度和1转动自由度。这组并联机构中有4种同构支链机构,每一条支链均内含1个(S-S)2四边形杆组,差异之处是主动关节的形式或支链在动、定平台之间的布位方式彼此不同。根据这4种同构支链并联机构的结构组成分析,建立机构动平台及支链的力学平衡方程,得到机构的力雅可比矩阵。在此基础上采用线几何法对同构支链并联机构的位形奇异性进行分析,给出机构发生支链奇异、平台奇异和驱动奇异的判别条件,分析机构在奇异位形的运动性质。针对一种同构支链并联机构,列举机构处于支链奇异、平台奇异和驱动奇异状态时的位形示例。H4 mechanism corresponds to a group of parallel mechanisms with good dynamical character,the center components of their movable platforms have three translational DOFs and one rotational DOF. In this group of mechanisms there are four isomorphic sub-chain mechanisms,each sub-chain includes one （S-S）2 quadrilateral bar-suit,and the difference of these four mechanisms is in that their actuated joints or the sub-chains＇ deployment between base and movable platforms are different. Based on the structure analysis of isomorphic sub-chain mechanisms,the force equilibrium equations of movable platform and sub-chain are established,and force Jacobian matrix are obtained. On which the singularities of the four mechanisms are analyzed by using line geometry method,the discriminating conditions of sub-chain singularity,platform singularity and actuator singularity are proposed,and the kinematic characters of mechanisms at singularity configurations are analyzed. Finally,the configuration examples of an isomorphic sub-chain parallel mechanism in the states of sub-chain singularity,platform singularity and actuator singularity are illustrated.

关 键 词：H4并联机构 同构支链 力雅可比 线几何法 奇异性 

分 类 号：TH112[机械工程—机械设计及理论] TP24[自动化与计算机技术—检测技术与自动化装置]