Controller synthesis for assistive robotic device using twisted-string actuation

In this paper, an adaptive robust controller of assistive robotic device using a dual twisted-string actuation devices was synthesized. With the consideration of system uncertainties, nonlinear dynamics, and operational dead-zones, a compensation strategy for high accuracy motion control is integrated in the controller. The proposed controller not only accounts for the tracking performance but also minimizes synchronization errors of the dual-axial system. A test platform was designed to validate the performance of the proposed ARC controller, which can achieve tracking performance of individual twisted-string actuation and minimize the synchronization error simultaneously. The performance of the proposed ARC controller was compared with the outcome of regular PID controller as well.