Workspace analysis of a parallel manipulator with one redundant DOF for skull-base surgery

A parallel manipulator can be used for medical operations for its high stiffness and motion accuracy. However, the small and oddly distributed workspace of the general manipulator limits its applications. In this paper, a special manipulator which has a redundant degree of freedom (the 7-DOF) is introduced to improve the workspace. The workspace of the manipulator was analyzed with respect to the selected orientations. Two configurations of the 7-DOF were considered. The preliminary result of the analysis shows that the workspace of the manipulator can be effectively improved with the redundant degree of freedom.