Elimination Method for the Stiction Induced Control Loops Oscillation

Pneumatic valve stiction fault is often a common problem in control loops,and stiction induced oscillation is the main cause of poor performance in control systems.For valves without a positioner,this paper proposes the use of T-S type fuzzy controller instead of the traditional PI controller to eliminate such oscillations.When the valve is sticky,using the relations between the status information of the controlled object and the change rate of the controller output to build the fuzzy control rules.Adjust the integrator coefficient of traditional PI controller so that the valve can quickly get out of the sticky area and eventually eliminate the impact of stiction on the control loop.The actual level control results show that the compensation algorithm can eliminate control loops oscillation well and the controller is robust enough to adapt to different set values.