Compensation of valve deadzone using mixed integer predictive control

Abstract

Stiction is a nonlinear friction phenomenon that causes poor performance of control loops in the process industries. In this work, we develop a mixed-integer MPC (Model Predictive Control) formulation including valve dynamics for a sticky valve in order to improve control loop performance. The introduction of the valve nonlinearity into the model prevents the MPC from requesting physically unrealistic control actions due to valve stiction. Simulation studies using a two-tank systems show that, if the deadband value is known apriori, the Mixed-Integer Quadratic Programming (MIQP) can effectively improve the closed-loop performance in the presence of valve stiction. © ECMS Zita Zoltay Paprika, Péter Horák, Kata Váradi,Péter Tamás Zwierczyk, Ágnes Vidovics-Dancs, János Péter Rádics (Editors).