Smith Predicted Type Robust PI Controller with Adaptive Modification for the Thickness Control in the Rolling Mill

Abstract

This paper proposes a new thickness control method for the rolling mill using the robust PI controller with Smith predictor and adaptive modification. In the rolling process, Several kind of AGC (Automatic Gage Control) were proposed. However, there remain problems that are an absence of robust stability and the difficulty of tuning and maintenance for the parameter change. The proposed method compensates the time delay by Smith method and stabilizes robustly the Smith predictor having vulnerability for the parameter change. And the adjustment and the maintenance of the contoroller become easy, because the PI controller is used as the main regulator. Moreover, Adaptive modification for the accelerating rolling speed enable the excellent thickness property every part of the strip. The results of numerical experiment show the usefulness of the proposed controller.