2 PRS-2 PSS并联机构的设计与运动学分析

摘要

A new two-translational and two-rotational 4-DOF 2PRS-2PSS parallel mechanism was proposed.Orientation angles among axis of all actuated prismatic j oints and fixed base of the parallel mechanism were variables.Firstly,the motion output characteristics were analyzed by theory of posi-tion and orientation characteristics.The kinematics of the mechanism was analyzed by using vector ap-proach.Forward and inverse solutions of the position and orientation of the mechanism were derived. Then, the equations of velocity and acceleration were obtained. In addition, the singular configurations of the mechanism were discussed in detail based on the singularity of its Jacobian matri-ces.Finally,simulation results show that the theoretic analysis is correct.%设计出一种两移动两转动的四自由度2PRS-2PSS并联机构。以该机构的4条分支运动链的主动移动副轴线与静平台的夹角为变量。首先根据方位特征集理论分析了该并联机构的运动输出特性；再基于矢量法对其运动学进行分析，推导出机构的位置和姿态的正解、逆解，进而推导出其速度和加速度方程；然后基于机构雅可比矩阵的奇异性，详细讨论了机构可能存在的奇异位形；最后，通过算例仿真验证了理论分析的正确性。