Application of control system considering pressure response of air cylinder for pneumatic stage

Abstract

In the pneumatic stage, the differential pressure is the driving force. For this reason, it is indispensable for fast positioning to change the pressure in the chamber instantaneously. The piston in the air cylinder moves when the stage is driven. As a result, the volume of the chamber increases or decreases during positioning. Therefore, the pressure in the chamber changes not only by the opening and closing operations of the left and right servo valves but also by the increase and decrease of the chamber volume. Here, in order to drive the stage under high-speed, the chamber volume must be rapidly changed. At this time, the influence of the pressure change due to the chamber volume cannot be ignored and the differential pressure becomes small. This hinders realization of fast positioning. Therefore, the pressure response is improved so that the pressure change due to the servo valves is more dominant than that due to the chamber volume. In this paper, we propose opening operation of the exhaust side valve. It was demonstrated that symmetrization of left and right pressure responses using the proposed method enables fast positioning. Furthermore, it was confirmed that similar effects can be obtained in the control system in combination with pressure feedback.