Kinematics analysis and solution of the active/passive forces of a 4SPS+SPR parallel machine tool

摘要

A 5-dof 4SPS+SPR parallel machine tool with four SPS-type active legs and one SPR-type active leg is proposed. Its inverse kinematics is analysed by using an analytic approach and a CAD variation geometry approach. Some analytic formulae for solving the active/passive forces are derived by adopting a vector approach. First, a simulation mechanism of the 4SPS+SPR parallel machine tool is created and some kinematic characteristics are analysed. Second, the formulae for solving its inverse kinematics and the Jacobian matrix are derived and a reachable workspace is constructed. Third, the poses of the active/passive forces are analysed and an active/passive force transformation matrix and the analytic formulae for solving the active/passive forces of the 4SPS+SPR parallel machine tool are derived. The analytic results are verified by the simulation mechanism.