Torque Mode Control of a Cable Driven Actuating System by Sensor Fusion

Abstract

A cabledriven actuating system is proposed in this paper. The proposed system is attractive for rehabilitation systems because the weight of the actuator is not imposed on the human body. Since the endeffector and the actuators are connected by Bowden cables, the humans are allowed to freely move in a certain range while being assisted. However, it is a challenge to account for the variable friction of the Bowden cable and the inertia and friction of the actuator in the design of control algorithms. In this paper, a hierarchical control strategy is adopted to control the proposed cabledriven actuating system. To determine the reference trajectory of the motor in realtime, a sensorfusion method based on a kinematic Kalman filter with MEMS accelerometers is proposed. By the proposed control methods, the cabledriven actuating system realizes a precise forcemode actuation. The system performance is evaluated by experiments.