Backstepping Sliding Mode Control for the Speed and Tension System of Reversible Cold Strip Rolling Mill Based on Tracking Differentiator

In this paper, in order to improve the coordinated tracking control performance for the speed and tension system of reversible cold strip rolling mill, a backstepping sliding model control strategy is proposed based on tracking differentiator (TD). Sliding model controller for each of the speed and tension subsystems is designed based on backstepping respectively, which improve the coordinated tracking control performance and robustness of the system effectively. Moreover, the TDs are adopted to estimate the virtual control laws and their first time derivatives, which avoid the “differential explosion” phenomena during using the backstepping control, and optimize the controller structures. Theoretical analysis shows that the resulting speed and tension closed-loop system is uniformly ultimately bounded stability. Finally, simulation research is carried out on the speed and tension system of a 1422 mm reversible cold strip rolling mill by using the actual data, and results show the superiority of the proposed control strategy in comparison with the decentralized overlapping control strategy.