Coordinate control of strip thickness-crown-tension based on inverse linear quadratic in tandem hot rolling mill

In order to further improve the control accuracy of thickness, crown and tension in hot strip finishing mill, a multivariable optimizing strategy based on inverse linear quadratic (ILQ) control theory is proposed in this paper. First, the state space model of hot rolling process is established based on the basic dynamic mathematical model of rolling process and measured data collected from a certain plant. Then, the new ILQ control strategy is designed for the thickness, crown and tension control system in the complex rolling process, and the response performance and anti-interference performance of ILQ controller and PI controller were tested. The results show that the proposed ILQ control strategy has excellent control performance with the maximal overshoot 24.13% smaller than that of PI controller when strip crown, thickness and tension step signals are added simultaneously, and the ILQ control strategy has certain guiding significance for the actual production of hot rolling.