Discrete Model Predictive Control Scheme for an Integrated Gauge-Looper Control System in a Tandem Hot Strip Mill

There exists strong coupling and a complex multivariable relation among the strip gauge, looper angle and strip tension in tandem hot rolling. To improve the gauge precision of the hot strip, the dynamic relationship among these three variables must be determined. In this paper, a new coordinated optimal control scheme based on discrete model predictive control (DMPC) theory was presented for an automatic gauge control and looper control (AGC-LP) integrated system. First, a state-space model of the AGC-LP integrated system was established based on a 1700 mm tandem hot strip mill. Then, to achieve the desired dynamic performance with the AGC-LP integrated system, a performance index function and an optimal control sequence were designed for the DMPC controller. The simulation results showed that the proposed DMPC controller had better robustness and adaptability to modeling uncertainties and external disturbances than a traditional proportional-integral (PI) controller.