A New Unified Approach to Valve Stiction Quantification and Compensation

Abstract

Satisfactory control loop performance has always been a vital objective in process industries for economic reasons. However, unsatisfactory performance may prevail, of which valve stiction is a common culprit. In this work, a new unified approach is introduced to quantify valve stiction in control loops and then compensate for it. The newly proposed stiction quantification method uses a one-parameter stiction model and is based on a modified Hammerstein identification approach. In conjunction with the stiction quantification algorithm, a novel compensation technique that adds a constant amplitude signal to the valve input signal is presented. The effectiveness of the proposed scheme is demonstrated using simulation examples.