3-RRR平面并联机构的拓扑结构优化及其运动学性能改善

Optimizing Topological Structure of 3-RRR Plane Parallel Mechanism and Improving its Kinematic Performance

典型3-RRR平面并联机构是一种具有两平移一转动输出的平面定位、传送装置,其应用较广。首先计算出该机构的耦合度k=1;其次,基于结构降耦原理,设计出一种零耦合度(k=0)的平面定位传送降耦机构,从而极易求得其位置正解解析式,且使得动平台的输入-输出具有运动解耦性;进一步,对该降耦机构的工作空间、奇异位形进行了分析。比较表明:降耦机构比原始机构的综合性能更为优越,结构降耦是机构拓扑结构优化的一种有效方法。

The typical 3-RRR planar parallel mechanism has two translations and one rotation and thus is a kind of extensively applied plane location and transfer equipment. Firstly, the coupling degree of the parallel mechanism is calculated to be k = 1. Then, based on the structural coupling reduction principle, this paper designs its coupling reduction mechanism with zero coupling degree, which not only leads to its easy analytic direct kinematic solution but also makes the input and output of the moving platform partially motion-decoupling. Moreover, the workspace and singularity of this coupling reduction mechanism are also performed. Finally, the comprehensive comparison of two types of the coupling reduction mechanism shows that the main performance of the structural coupling reduction mechanism is better than that of the original mechanism, indicating that the structural coupling reduction mechanism is an effective method for optimizing the topological structure.