动/静平台非一致型并联机构构型分析及设计方法

Analysis and Design Method for Non-uniform Parallel Mechanism Structure of Dynamic/Static Platform

针对动/静平台非一致型并联机构的设计需求,提出一种基于尺度综合的机构构型设计方法。根据拓扑结构设计理论对目标自由度并联机构支链进行构造;确定平台联结铰点的数量及类型,对机构进行初步设计及动平台自由度校核;以一种五自由度动/静平台非一致型并联机构为例,运用一次尺度综合对机构尺寸参数进行一次改进,建立机构初步模型;定义冗余支链和角部支链,通过二次尺度综合对冗余支链位置进行二次改进,完成机构所有尺寸参数的计算,给出机构的整体模型;与相似尺寸下、相近工作空间内Stewart机构的局部传递指标图谱进行对比分析,该机构具有良好的运动/力传递性能,验证了所提出的并联机构构型设计方法的正确性和可行性。

Aiming at the design requirements of non-uniform parallel mechanism of moving/static platform,a configuration design method based on dimension synthesis is proposed.The limb of target degree of freedom parallel mechanism is constructed according to topology design theory.The number and type of platform joint points are determined,the mechanism is preliminarily designed and the degree of freedom of the moving platform is checked.Taking a five-degree-of-freedom dynamic/static platform non-uniform parallel mechanism as an example,the first dimension synthesis is used to improve the dimension parameters of the mechanism,and the preliminary model of the mechanism is established.The redundant limb and the angular limb are defined,and the position of the redundant limb is improved by the secondary dimension synthesis.The calculation of all the dimension parameters of the mechanism is completed,and the overall model of the mechanism is given.The reference analysis of the local transmission index map of Stewart mechanism with similar size and similar workspace is carried out,which shows that the mechanism has good motion/force transmission performance,and verifies the correctness and feasibility of the proposed configuration design method of parallel mechanism.