Kinematic Performance Analysis of a Novel Redundantly Actuated Parallel Mechanism

This paper presents a novel redundantly actuated parallel mechanism with two rotations and one translation degrees of freedom. Firstly, the kinematic inverse position and the parasitic motion of the parallel mechanism are explicitly expressed. Secondly, the Jacobian matrix of parallel mechanism is derived intuitively via an alternative approach based on the screw theory with consideration the relationships between actuations and constraints. Furthermore, The Jacobian matrix of the cable-driven mechanism is acquired. In combination with the relation, a dimensionally homogeneous Jacobian matrix of the redundantly actuated parallel mechanism is formulated. And more importantly, kinematic performance evaluation indices are established on a case-by-case basis. By numerical examples, performance indices on the kinematic dexterity and stiffness are tremendously improved. The corresponding results illustrate that the proposed parallel mechanism has better kinematic dexterity and superior stiffness performance than the non-redundant parallel mechanism, which proves the validity for applying this redundantly actuated parallel mechanism.