Kinematics and Closed Optimal Design of a Kind of PRRRP Parallel Manipulator

This paper addresses optimal kinematic design of a PRRRP (P-prismatic joint, R-revolute joint) parallel manipulator that is horizontally actuated by linear actuators. Kinematically, the symmetrical PRRRP parallel manipulator has only one geometric parameter, i.e., the link length of each of the two legs. Here, we propose a design approach utilizing a performance chart and local performance specification. The key problem in the design of the manipulator is the determination of not the link length but the workspace that the manipulator can reach satisfying the design specification. Such a kind of workspace when the link length unit is defined as the basic good-condition workspace (GCW). For the manipulator studied here, the link length is actually the ratio of the desired task workspace to the basic GCW. This paper gives an effective method to obtain the basic GCW with respect to indices in closed forms. One of the advantages of the method is that the basic GCW is achieved by taking into account both the global and local indices.