Design and torque-mode control of a cable-driven rotary series elastic actuator for subject-robot interaction

To achieve a compact, lightweight and compliant actuator design for intrinsically safe subject-robot interactions, a Bowden cable-driven rotary series elastic actuator is proposed in this paper. To realize the zero output torque control of the proposed actuator in the presence of variable friction of the Bowden cable, a disturbance observer based torque-mode control algorithm is developed and analyzed. The effectiveness of the proposed design is verified by experiments with a human subject.