Valve stiction compensation based on equivalent-input-disturbance approach

The presence of stiction in a control valve causes loop oscillation, and limits the control loop performance. To address this problem, the paper proposes a method based on equivalent-input-disturbance (EID) to control valve stiction. In this method, a classic two-parameter stiction model is adopted. Then, an EID estimator is utilized to estimate the effects of valve stiction in control system. And the controller is designed in the spirit of repetitive control. The simulation control results are compared with the traditional method. The results demonstrate that the proposed EID method can effectively improve the control performance of valve stiction and eliminate the stiction-induced oscillations.