Control of mass flow in a hot strip mill using model predictive control

This paper reports on the control of mass flow using MPC. The process to be controlled comprises six mill stands, six main drive speed control systems and the existing PI based flow rate control system. The latter is preferably not switched off, so as to minimize changes in the process when testing MPC. Controlled outputs are looper angles, while drive speed reference trims are the manipulated inputs. There are hard constraints on several outputs. A simplified model of the mass flow process, constructed from a full non-linear simulation model, is used by the MPC controller. Simulations on a detailed nonlinear model of the full process controlled by MPC indicate it is feasible, and can lead to considerable performance improvement.