Teleoperation of two six-degree-of-freedom arm rehabilitation exoskeletons

This paper presents a teleoperation system for two six-degree-of-freedom ARMin arm rehabilitation skeletons. Two control strategies are presented: unilateral teleoperation, which is realized with proportional-derivative controllers, and bilateral teleoperation, which is realized with compliance control and torque feedback. An empirical procedure for identifying the best control gains of the unilateral teleoperation system is presented, and the stability of the bilateral teleoperation system is demonstrated theoretically. Evaluations with healthy subjects showed that trajectories can be learned through the teleoperation system and that the torque feedback allows one human user to determine whether the other human is participating in the movement, resisting it, or remaining passive. The paper concludes with a discussion of potential applications of the system, including telerehabilitation and group rehabilitation.