基于Jacobian矩阵的5UPS-RPS并联机构全域性能指标分析

提出一种由一个RPS约束分支和5个UPS主动分支构成的新型空间对称五自由度并联机构.为研究动平台和定平台半径变化对该五自由度并联机构速度性能指标的影响规律，利用虚设机构法求出机构一阶和二阶影响系数矩阵，并推导了速度和加速度表达式，利用推导的Jacobian矩阵对机构进行速度全域性能指标分析，并绘出上述性能指标图谱，得到动平台和定平台尺寸变化对并联机构性能的影响趋势，同时也得到所给动平台和定平台尺寸范围内速度性能较好的尺寸，为机构优化设计提供了理论依据. 

Analysis for Global Performance Index of 5UPS-RPS Parallel Mechanism Based on Jacobian Matrix

A novel 5UPS-RPS 5-dof parallel mechanism with one RPS-type constraint leg and five of the same UPS-type active legs was presented.First,the characteristics of this PM were introduced,the first-order and second-order comprehensive influence coefficient matrix were derived by virtual mechanism method,and analytic formulas for solving the velocity and acceleration of this PM were derived systematically.Second,the velocity global performance index for the optimization of this parallel mechanism in the workspace was derived based on the condition number of Jacobian matrix. Then the dimensions of the fixed base and moving platform with good kinematic performances were derived in the workspace. Furthermore, theoretical analysis on velocity global performance index provides a foundation for the optimization design of this parallel mechanism in the future work.