Abstract
The speed control of a pneumatic motor is usually of an open loop type, adjusted manually by a flow control valve. Using it for the automatic control, the closed loop control is desired.
In this paper, the feedback speed control of a radial piston motor with an electro-pneumatic proportional valve is studied. To realize satisfactory control without sacrificing the low cost of pneumatics, the I-PD control scheme in which the controller is simply installed by proportional, integral and derivative elements is employed. The design of control system is based on the partially model matching method. The performance of the control system is discussed to obtain the following results.
1) By employingth e I -PDc ontrol, a satisfactoryc losedl oop speedc ontrols ystemf or a pneumatic motor can be cheaply constructed.
2) In this system, if either the reference speed or the load torque is increased up to the saturation point of the proportional valve opening, the step response becomes more oscillatory.
3)The derivativer eference speed feedforward is effective to improve the starting characteristics of the system.
