球面并联机构的结构降耦及其位置正解求解
The Reducing in Structure Coupling and the Forward Position Analysis for the Spherical Parallel Mechanisms

基于一般结构的S+3-SPS球面机构的耦合度分析，通过动平台二球副重合的方法，使之结构降耦演变为0耦合度球面机构，并得到其位置正解的解析解；而对于k=1的一般结构的S+3-SPS，虚设一条支链使机构包含k=0的零耦合度机构，再在约束度为-1的支链上建立一个一元运动相容性方程，并采用一维搜索法求得全部正解数值解。这种基于耦合度分析的求解并联机构位置正解的程式化通用方法，易于实现计算机自动生成，并适用于其它含SPS支链并联机构位置正解的快速求解。
The coupling degree of S+3-SPS spherical mechanisms with general structure is reduced and the mechanism turns into another spherical mechanism of which the coupling degree is 0 and analytic solutions of forward position analysis are obtained by overlapping two spherical joints on the moving platform. For S+3-SPS spherical mechanism whose coupling degree is 1, by adding a branch chain virtually, the mechanism contains the above mechanism whose coupling degree is 0. A consistent equation of movement which contains only one variable is established on the base of a chain whose constrain degree is -1. Finally, using one-dimensional search method, all real forward position numerical solutions of the present mechanism are obtained. Based on the coupling degree analysis, the stylized generic numerical method is easy to accomplish computer programming and can also be applied to solve other parallel mechanisms rapidly which contain SPS type branch chain