Design of a Three-Chain 6-DOF Symmetrical Parallel Mechanism and Solutions of Its Forward and Inverse Kinematics

A low coupling degree 6-DOF parallel mechanisms (PMs) with three identical hybrid branches (5R-RS) and orthogonal arrangement is firstly proposed. The main topological characteristics such as position and orientation characteristics (POC), degree of freedom (DOF), of the PM are analyzed. Secondly, the forward position equations and the inverse position solution of the PM are derived. Moreover, Newton iteration method is used to solve the forward position equations. Finally, correctness of solutions for its forward and inverse kinematics of the PM is numerically proved.