Feedback linearization for pneumatic actuator systems with static friction

Though pneumatic actuators are widely used in industrial applications, it is not easy to control them because of the nonlinearities in the valve, the compliance variation and the generating force. In this paper, a method of feedback linearization is applied to a pneumatic actuator system to handle the nonlinearities. It is shown that any single-input pneumatic system with a linearizable load and an isothermal pneumatic actuator is linearizable by state feedback. In addition, feedback linearization with step-type disturbance rejection is proposed by measuring disturbances, which is useful for pneumatic systems with static friction. Experiments with a rubber artificial muscle actuator that has hysteresis characteristics caused by static friction are carried out, and verify the effectiveness of the proposed method. Copyright (C) 1997 Elsevier Science Ltd.