关键词: 并联机构, 封闭解法, 位置正反解, 六自由度

Abstract:

Kinematics based on a new 6-DOF 3-PRRS parallel mechanism were studied, the analytical form of inverse kinematics was got  and closed analytic method was used to study all the forward position solutions. According to the effects of two different revolute pairs on the moving platform,coordinate transformation was used and the angle variables φi  were  introduced to obtain the coordinates of three points on the moving platform. And the constant length between the three points on the moving platform was regarded as the restrict condition to obtain the constrained equations.Then three transcendental equations with  φi  as  variables were obtained,and 16 times linear algebraic equation was obtained by elimination method. MATLAB software was used to solve all the forward position solutions.Finally,a numerical example was used to verify the validity of the theories and conclusions. Thus the foundation for dimensional synthesis, singularity analysis, output error analysis and trajectory control of the new 3-PRRS parallel mechanism applied on the virtual-axis hexapod machine was laid.

Key words: parallel mechanism;closed analytic method;inverse , and , forward , position kinematics;6-DOF