Looper-Gauge Integrated Control In Hot Strip Finishing Mill Using Inverse Linear Quadratic Theory

Hot strip rolling is a significant process in the fields of manufacturing and processing. In order to further improve the control accuracy of looper angle, strip tension and gauge in hot strip finishing mill, an innovative looper-gauge integrated control scheme is developed in this paper. Based on the inverse linear quadratic (ILQ) theory, a proposed control scheme is designed for the looper-gauge integrated system. First, considering the numerous interactions between looper angle, strip tension and gauge, and the disturbances from several sources, a dynamic 6th order state space model is established and validated. Then, the control scheme based on ILQ theory is imported into gauge-looper integrated system. The desired poles are placed according to the dynamic characteristics requirements. The state feedback optimal control law is determined by an improved ILQ design method. Then the multivariable looper-gauge integrated control system is constructed. The proposed control scheme has the explicit ability to achieve desired looper and gauge control performances, with less external disturbances and no sensitivity of strip dimension changing. The effectiveness of the proposed looper-gauge integrated control scheme compared with traditional control strategies is shown in the simulation results. The interactions between looper control and guage control are also minimized.