Kinematic Performance Analysis on a New Spatial Rotation 3-DOFs Parallel Robot Mechanism

In this paper, kinematic performance of a new spatial rotation 4-SPS-1-S parallel robot mechanism is investigated. The 4-SPS-S parallel robot mechanism has spatial three pure rotation degrees of freedom, it can achieve spatial roll, pitch and yaw rotation movements, and possesses high bearing capacity, stiffness and stability. Inverse position analysis and velocity mapping equation is established to obtain Jacobian matrix of the mechanism. Based on the introduction and computation of Jacobian matrix, the kinematic performance index is defined using Jacobian matrix conditioning number, also an analysis equation for calculation Jacobian matrix conditioning number of the mechanism is developed. Finally a case study is provided for analyzing the kinematic performance index's distribution rules over the entire workspace. Results show that the mechanism has no singular configurations in its workspace; its structure is closed to isotropic and has sound kinematic performances. The paper provides important references for future mechanism design of this class of parallel robot mechanisms.