Dynamics and motion control of a three degree of freedom 3-prrr parallel manipulator

Abstract

This work focuses on the dynamic modelling and motion control scheme of a parallel manipulator which has three legs of prismatic-revolute-revolute-revolute joint setup. In each of the legs, the prismatic (P)-joint is active and the rotary (R)-joints are passive. The three legs further join into an end-effector in a right-angled triangle shape. The Euler-Lagrangian approach is followed to achieve the dynamics of the manipulator. The formulations are detailed and simulated. This paper also presents an augmented proportional-derivative (PD) controller along with gravity compensation for the motion control. This control method transforms the closed-loop dynamics of the manipulator into decoupled, and thus it becomes easier to quantify the motion performance. The trajectory tracking performance and its accompanying errors are also discussed.