Stiffness analysis of a 3-DOF parallel mechanism for engineering special machining

Abstract. There are considerably rigorous requirements for accuracy and stability of the mechanism to accomplish large-scale complex surface machining tasks in aerospace field. In order improve stiffness performance parallel mechanism, this paper proposes a novel three degrees freedom (DOF) redundantly actuated 2RPU-2SPR (where R, P, U S stand revolute, prismatic, universal spherical joints, respectively) mechanism. Firstly, kinematics position inverse solution is derived dimensionless generalized Jacobian matrix established through driving constraint matrix. Secondly, model deduced verified finite-element analysis. Using eigenscrew decomposition illustrate physical interpretation matrix, equivalent six simple screw springs. Finally, simulation experiment results demonstrate that has better compared traditional 2RPU-SPR