Modeling and multivariable active disturbance rejection control of a hydraulic looper multivariable system

Controlling the looper height and strip tension is important in hot strip mills, because these variables affect both the strip quality and strip threading. Many researchers have proposed and applied a variety of control schemes for this problem; however, the increasingly strict market demand for strip quality requires further improvements. This paper describes a Multivariable Active Disturbance Rejection Control (MADRC) strategy that realizes the decoupling control of a hydraulic looper multivariable system. Simulation experiments of a traditional Proportion-Integration (PI) controller and the proposed MADRC controller were conducted using MATLAB/Simulink software. The simulation results show that the proposed MADRC ensures good robustness and adaptability under modeling uncertainty and external disturbance. It is concluded that the designed MADRC controller produces better dynamic performance than the traditional PI controller does, and the proposed looper control system is effective and practical.