Kinematics and Workspace Analysis of 5-DOF Hybrid Redundantly Driven Mechanism

Abstract

A novel 5-DOF (5-SPS)+5R2U hybrid redun-dantly driven mechanism (HRDM for short) is proposed, which can realize 3 translations and 2 rotations (3T2R) movements. (5-SPS)+5R2U parallel mechanism is composed of six driving limbs. Of which 5-SPS (S represents spherical pair, P represents prismatic pair) limbs are symmetrically distributed at the center point of static and moving platform have no restriction on the degrees of freedom of the mechanism. The middle limb (7R)U (R represents revolute pair, U represents Hooke joint) is connected to the static platform and the center point of the moving platform. It is jointly driven by constant velocity motor and servo motor, and plays a role of restraining the freedom of the whole mechanism. It is called hybrid redundantly driven limb (HRDL for short). Hybrid-driven mechanism and redundantly actuated mechanism can be integrated into one mechanism by HRDL, which can give full play to the advantages of both. The inverse position solution model of the mechanism is established, and the velocity Jacobian matrix and acceleration expression are derived to obtain the velocity and acceleration variation laws of the me-chanism. On this basis, the factors affecting the workspace are analyzed, and the workspace atlas under different orientation angles is obtained. The results provide theoretical model for the realization planning trajectory of (5-SPS)+5R2U HRDM.