Design and Implementation of a Pneumatic Servo System using Conventional Direction Control Valve

Abstract

Pneumatic servo systems are widely used in industrial applications but they are expensive, so decreasing their cost contribute in decreasing products manufacturing cost. In this research a pneumatic servo system (PSS) was designed and implemented using cheap conventional directional control valve (CDCV) instead of expensive servo or proportional valves. The CDCV was driven using pulse width modulation (PWM) technique, which was generated in the LabVIEW program and send to the CDCV via Arduino uno microcontroller board. A fuzzy PI controller was designed and implemented to overcome the nonlinearity inherent in air systems, resulting from air compressibility and dry friction, and the nonlinearity resulting from the use of a CDCV which is a digital valve. It is found that getting acceptable results require using PWM technique with frequencies greater than 90 Hz. The results showed that increasing the applied pressure leads to a significant decrease in the rising time but accompanied with a noticeable increase in the ripple amplitude. So, getting accepted results require choosing the applied pressure experimentally to suit the applied load, since they are affected by the applied load.