1999 Volume 1999 Issue 4 Pages 149-154
The basic characteristics of pneumatic cylinder drives are remarkably low natural frequency and fairly low damping. Themain purpose when designing a controller for a demanding servo application is to find out a good and practical method toincrease system damping. One of the most effective ways to increase the damping of a cylinder drive is to use a suitable controller. The most common and success ful controller is so-called State controller. A state controller has three cascadeloops. The total gain of each loop contains also the flow gain of a servo valve. Typical supply pressure in an industrialapplication is about 7 bar (abs.). Since the tuning of a demanding position servo is often quite critical, the fluctuating ofthe supply pressure might in fluence the performance of the system. This paper deals with the influence of the supply pressure on the positioning accuracy and the dynamic behaviour of a pneumatic position servo system. The influence ofthe size of normal pressure reducing valve (a pressure control valve) on the performance of a position servo system isstudied and experimental results are presented. Also the effect of the amount of extra volume between the pressure controlvalve/filter and the servo valve is studied and experimental results are shown.