Fixed-time Backstepping Control for the Speed System of Cold Strip Main Rolling Mill Based on Extended State Observers

Aiming at the speed tracking control problem of the main rolling mill system in reversible cold strip rolling mill, a fixed-time backstepping control method is proposed based on extended state observers in this paper. Consider the main rolling mill speed system is characterized by nonlinearity and uncertainty, so the extended state observers (ESOs) are constructed to observer the system's comprehensive uncertainties, which effectively improve the tracking control precision of the system. Next, the speed subsystem controller and the flux linkage subsystem controller are designed respectively by combining the backstepping control and the fixed-time control, which improve the robust stability of the system, and ensure that the main rolling mill speed system state can be stable in fixed time. Finally, by comparing the proposed control method with the dynamic surface backstepping control method in Ref. [10], and simulation results verify the effectiveness of the proposed control method.