RESEARCH ON PNEUMATIC POSITION CONTROL SYSTEM BASED ON A NEWLY-DEVELOPED ROTARY ACTUATOR WITH A BUILT-IN BRAKE

Abstract

In this paper, a newly developed pneumatic rotary actuator is introduced, which is specially designed for angular position control. The actuator incorporates a built-in air brake and an angular displacement sensor. The basic behavior of the brake is tested. On this basis, for angular position control some control systems are proposed. The first system is the on-off valve-based position control system, which has the advantages of simple control algorithm, easy implementation and lower cost. The second system is the proportional valve position control system with simple PID algorithm, which can reach a required positioning accuracy but with a lower stiffness against disturbance. The third system is the proportional valve position control system with a composite control strategy of PID combined with brake aided positioning, which can reach the same positioning accuracy and no overshoot with disturbance takes place, as compared with the simple PID.