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In order to improve the control accuracy of strip head thickness in rolling process, a head thickness prediction model based on tensor CP decomposition is proposed in this paper. In the prediction model, the input data are composed of a tensor index matrix composed of rolling speed, rolling force, roll gap, inlet temperature and thickness parameters, and the output is the factor matrix composed of various rolling parameters that affect the thickness trend. To solve the problem of tensor sparseness in rolling data, a gradient-based CP-WOPT method is used to decompose tensor weights. The head thickness prediction and simulation of strip with rolling thickness of 3mm and 6mm were carried out, and the relative errors were 88.25% and 84.9% within ±2%, respectively. The prediction accuracy meets the actual demand, and verifies the feasibility of the prediction method.

Vertical mill is usually installed on the roughing trains to improve the width of the slab control precision and adjust the shape of edge during hot rolling. Because of the high ratio of width to thickness in edge rolling, the deformation of slab is mainly restricted in a small zone on the edge and this is different from the horizontal rolling. There is not a suitable formula to calculate the edge rolling force. With variable upper limit integration, the GM (Geometrical Midline) yield criterion and mean value theorem, as well as the vector inner product method are used respectively in integration of plastic deformation, shear and friction power terms. Then analytical solutions of slab total power functional and rolling force in edge rolling are obtained. The analytical rolling force of the model is in good agreement with those of data in a strip rolling plant. By this proposed analytical model, it is noted that the calculation time and computer expense are saved, and the precision can satisfy the requirement of production control.

Hydraulic gap control system is the inner loop of automatic gauge control system, and the dynamics of hydraulic gap control system is the key factor for the high precision gauge control effect. The dynamics of hydraulic gap control system is influenced by a non-linear part since the oil flow of valve port depends not only on the control current but also on the changing rolling force. This influence is compensated by a method with compensation factor based on actual rolling force. The application indicates that the dynamics of the hydraulic gap control system is improved greatly with compensation.

Through the designing of Smith predictor and controller, the second-order engineering optimal controller parameters by fixed-timing sampling are given for the controlled object with pure delay inertia link, and the explicit formulation of control law is derived. Aiming at the problem of delay time changing with rolling speed, the solution strategy of using fixed-length sampling is proposed, and the optimal MN-AGC control strategy based on fixed-length sampling is given. This optimal controller has characteristic of pure integral, whether it is based on fixed-timing sampling or fixed-length sampling.

The automotive control system of hot strip mill’s laminar cooling, including water level control, feedforward control and feedback control of coiling temperature with smith predictor, is introduced. Steady water level can be got by water level control model, which is very important for water flux stabilization and the setup precision of process computer. Feedforward control strategy and feedback control strategy are necessary for the control precision of coiling temperature. This control system has been used on site and good performance has been got, which testifies that this system may be applied on the other hot strip mill’s laminar cooling system.