Power manipulability analysis of redundantly actuated parallel kinematic manipulators with different types of actuators

Spatial object manipulation is typically accomplished by parallel kinematic manipulators (PKM), whose number of actuators is equal to the required number of degrees of freedom. In order to improve the performance and reliability of PKM, their basic configuration can be extended by redundant actuators. This paper is devoted to the special case of PKM with both linear and rotational actuation, which can be operated simultaneously. Corresponding manipulators face the problem of coexisting translational and rotational joint space parameters inducing inhomogeneous Jacobian matrices. In this context, power manipulability ellipsoids provide a suitable performance evaluation for PKM featuring different types of redundantly applicable actuators. Accordingly, this research intends to analyze the kinetostatic performance of redundantly actuated PKM and to demonstrate their efficiency in contrast to non-redundant drive configurations. The analyses exemplarily are focused on the translational 3-RPC manipulator, since it can be equipped with both revolute and/or prismatic joint actuation.