Abstract
Pneumatic drive system is essentially a pressure control system and the response of pressure has to be improved to get better system performance. Since applications of pneumatics to force control and compliance control are expected, it is important to clarify the characteristics and the control scheme of the pneumatic drive system with considering the role of pressure.
This paper describes the double structured feedback control system for the position control of pneumatic drive system in which the variable gain pressure control system is included as an important internal system. In this system, the PD pressure control system with variable gains is constructed first. These variable gains compensate the effect of piston position by which the dynamics of the pressure response changes. Next, the reference of the pressure control system is produced by the proper controller from the error signal of the piston position. And the compensation for the disturbance caused by the fluctuation of friction force is considered and the compensating pressure is added to the reference pressure.
The experiment was carried out and the good position control was achieved. Improvement of positioning accuracy by the compensation of friction force was also confirmed. Thus the validity of this control system was clarified.
