Co-ordinated control of profile and shape in hot strip finishing mills with nonlinear dynamics

A method of modelling and controlling profile and flatness in hot strip tandem rolling mills is described. The method for controlling the profile is based on explicit manipulation of the strip thickness across its width. The flatness is controlled by appropriately distributing and constraining the profile actuators, so that defects do not occur. Model-based predictive control is employed to generate the control signal for each stand and to co-ordinate the stands for optimal profile and shape control. Simulation results are presented to demonstrate the performance of the proposed co-ordinated control scheme.