Modal System Design for Robot Manipulators with Combined Kinematic Redundancy and Actuation Redundancy

Kinematic redundancy and actuation redundancy contribute to the increased functionality and reliability of multi-degree-of-freedom (DOF) robot manipulators. The former refers to having more kinematic DOF than required for a given task, whereas the latter indicates having more actuators than required by the kinematic DOF of the mechanism. Combining these types of redundancy introduces rich functionality into mechanical systems; however, integrated control methods have not been sufficiently studied. This paper addresses solving these redundancies and proposes a control method for mechanical systems with both types of redundancy. Modal system design based on the statics of robot manipulators was adopted to solve actuation redundancy, and kinematic redundancy was treated separately. The proposed methodology was validated through experiments using a planar 3-DOF parallel robot with four actuators under hybrid position/force control.