A controller system design for pneumatic-powered motion assist device using a load observer

Abstract

This paper proposes a control system design for an exoskelton motion assist device for workers engaged in physically demanding jobs. The exoskelton is designed to provide supports to 1 degree of freedom rotational motion of shoulder and elbow joints and it uses McKibben pneumatic actuators as its power source. Key technical consideration in the control system design should be put on assuring good transient response of the device against the intention of the user wearing the device, while simultaneously providing sufficient force/torque to balance unknown loads. This paper presents two degrees of freedom control system which fully utilizes the improved version of the phenomenological dynamic model of McKibben actuators which has been proposed by the authors recently. Results of the load carry experiments indicate the effectiveness of the proposed control system.