Abstract
This paper describes the position control of a pneumatic artificial muscle antagonistic drive system in consideration of softness of a rubberless artificial muscle. The rubberless artificial muscle is a pneumatic actuator, and contraction mechanism is same as a general McKibben type artificial muscle. In this paper, the essential softness of the rubberless artificial muscle is expressed as a variable stiffness element based on its isometric contraction characteristic. We derive a passive stiffness model expression of the antagonistic drive system by using this variable stiffness characteristic of the artificial muscle. And we propose a control system to realize position control and adjusting the essential stiffness of the antagonistic system based on this expression. We confirm the validity of this control system experimentally.
