Torque control of a redundantly actuated passive manipulator

The study of passivity in the robotics domain has been motivated by safety and stability concerns in applications such as haptic displays, surgical robots, teleoperation, and manufacturing. This paper describes a passive manipulator with a redundant actuation scheme which allows for enhanced control capabilities and greater overall utility. An algorithm for determining passive actuator excitations from generally active control laws is presented. The torque translation algorithm is a graphical method based upon using knowledge of the specific passivity-induced constraints to select a subset of the available actuators to provide an acceptable output torque. The algorithm successfully provides a set of passive actuator torques for all manipulator states, and experimental results are given