Abstract: In view of the measurement delay perturbation and uncertainties in the cold rolling mill hydraulic automatic gauge control(HAGC) system, a new controller design strategy is presented to improve the accuracy of the strip thickness in practice. Based on the equation of each link of HAGC system, the mathematical model of system, which has measurement delay perturbation and uncertainties, is given. And the measurement delay is converted into input delay. Through these, the finial HAGC system model is presented. Based on this model, a new controller is proposed. The rigorous proof is given by use of the Lyapunov stability theory to obtain the exponential stability of system. The computer simulations for a 1700 single-stand rolling mill system are performed. Compared with the traditional proportional integral derivative(PID) controller, the results show that this method could overcome the effects of time delay perturbation and uncertainties in the system and have a better performance over traditional PID controller, which further confirms the effectiveness and superiority of the proposed control scheme.

Key words: cold rolling mill, controller design, hydraulic automatic gauge control(HAGC), measurement delay perturbation