Development of a dual-cable hand exoskeleton system for virtual reality

In this paper, a hand exoskeleton system for virtual reality is proposed. As a virtual reality interface for the hand, a wearable system should be able to measure finger joint angles and apply force feedback to the fingers with a simple and light design. In the proposed system, the finger joint angles are measured by a tendon-inspired cable mechanism. Also, another cable is used for force feedback to the finger. Using the measured finger joint angles and motor currents, the cable-driven actuation system applies desired force to the fingers. That is, when the desired force is zero, the motor position is controlled to track the changed cable length; when the desired force needs to be applied, the motor current is controlled to generate the desired force. For a smooth transition between two control strategies, linearly changing proportions of each control strategy is applied in the transition range. A prototype of the proposed system was manufactured, and the proposed control algorithms were verified by experiments.