Receding Horizon Control for Hot Strip Mill Cooling Systems

In a hot strip mill, the strip is cooled by spraying water from the top and bottom on the runout table (ROT) before the strip is coiled. The desired mechanical properties and metallurgical structure of the strip are achieved by controlling the cooling rate and temperature of the strip on the ROT. In this paper, we propose a design method of receding horizon control for controlling the temperature of a strip whose mathematical model is described by a nonlinear partial differential equation (PDE). We provide a fast numerical solution method for solving the nonlinear optimization problem for a class of nonlinear PDEs. Moreover, a state observer with an unscented Kalman filter for estimating the inhomogeneously distributed temperature of the strip is incorporated into the receding horizon controller. The effectiveness of the proposed method is verified by numerical simulation.