Effect of Dead Zone Compensation by Mass-Flow-Rate Twin-Drive System with Anti-Windup for Pressure Control System

抄録

Manufacturing equipment often require high-speed and high-precision positioning with long strokes. This study aims to utilize pneumatic cylinders for such equipment owing to their several advantages. One of the challenges in pressure and position control is valve nonlinearity, such as a varying dead zone. While the conventional feedforward dead zone compensation method cannot address variations in valve input-output characteristics, the twin-drive system, a feedback compensation method, can address the variations using a fast-response flowmeter. However, the disadvantage of the twin-drive system is that it is likely to cause saturation and windup. To solve this problem, we propose an anti-windup method for the twin-drive system. Experimental results indicate the proposed method avoids windup and enables accurate tracking control in the difference mode (i.e., mass-flow input to the tank). Moreover, the experimental results reveal that the proposed twin-drive system with the anti-windup structure improves the pressure tracking performance and enhances the pressure control system's linearity compared with those of the conventional feedforward compensation method.