3-RPS并联机器人机构位置正解的杆长逼近法

根据机构运动的同一性条件,给出一种求解3RPS并联机构位置的杆长逼近法,该算法的主要特点是通过逐步自动修正迭代初值,缩小搜索区间和步长,提高逼近精度,将二维搜索的杆长逼近化为一维搜索的杆长逼近·因此只要在分支的有效活动区域内任选初值,即可保证其收敛性并且不受机构奇异位形的影响,大大简化了搜索逼近过程并提高了迭代效率·给出了求解过程和逼近步骤及求解实例,其逼近精度达10-5·

Forward Position Analysis of 3-RPS In-Parallel Manipulator Using Self-modified Successive Approximation Method

A new scheme for the forward position analysis of 3 RPS in parallel manipulator, which is based on the fact that locations of three globular joints form triangle of the moving platform,is presented. In the successive approximation method,the joint positions of globular joints is determined by checking the distances of three sides of moving platform. In general numerical schemes, which determine a solution from a set of nonlinear simultaneous equations, the convergence rate varies with different joint inputs. The convergence of this method depends chiefly on approximative accuracy not on the joint inputs because joint inputs, search region and step are self modified successively in the process. There is also no influence on the neighborhood of singularity for the solution. The example was given, and running results of the program show the approximative accuracy can be 10 -5 .