Abstract: As the subject investigated, the planar 2-DOF parallel manipulator with actuation redundancy is treated as non-dimensional structure. The physical model of the solution space, which can reflect the scope in which the geometric parameters change, is presented. Kinematic equation is established, solution to inverse kinematics and velocity Jacobian matrix are given. The global performance indices of the manipulator are defined and calculated. The relationship between link lengths and global performance indices, such as condition number of Jacobian matrix, payload and stiffness are discussed; corresponding atlases are plotted in the physical model of the solution space. According to these atlases, the distribution rule of the three performance indices in the physical model of the solution space is concluded; the better dimension scope of each performance index is made out respectively. Finally, when the three performance indices are considered as the optimum indices simultaneously, the optimal dimension scope is obtained by synthesizing the three dimension scopes. These atlases give a possible path to optimize manipulator using kinematic performance indices. This method also provides a simple and effective way for designing parallel manipulator using computer-aided.

Key words: Actuation redundancy Global conditioning index, Parallel manipulator, Payload index Stiffness index