1 Department of Control and System Engineering/ University of Technology. Baghdad, Iraq

2 Department of Electromechanical Engineering/University of Technology. Baghdad, Iraq


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