A new stiction compensation method in pneumatic control valves

AbstractIn this paper, a new compensator is designed so as to eliminate the effect of stiction in the control loop. A wellknown stiction compensation method is proposed that reduces variability both at process variable and valve stem movement. Pneumatic control valves are widely used in the process industry. Stiction is the most common and one of the long-standing problems in the pneumatic control valves. It hinders the achievement of good performance of control valves as well as control loops. Compensate its effect is essential, because most of the sticky valves cannot be replaced and they remain working for months or years. Stiction compensation algorithms can mitigate this problem to a large extent. To understand the stiction phenomena and model it, the proposed stiction model is used which can be directly related to real valves. The simple and reliable model is further applied to the stiction compensation. The performance of the new stiction compensation method is examined with the proposed stiction model by using MATLAB / Simulink software environment and the results are illustrated using simulation case studies.