Modelling and dynamic surface backstepping recursive sliding mode control for the speed and tension system of the reversible cold strip rolling mill

Abstract

For the speed and tension system of the reversible cold strip rolling mill, a dynamic surface backstepping recursive sliding mode control (DSBRSMC) strategy is proposed based on the immersion and invariance (I&I) adaptive method and the nonlinear disturbance observer (NDO). First, a relatively complete mathematical model for the speed and tension system of the reversible cold strip rolling mill driven by alternating current (AC) asynchronous motors is established. Next, the I&I adaptive method is adopted to estimate the system perturbation parameters, and the NDO is developed to observe the system uncertainty. Again, controllers for the speed and tension system are presented by combining the backstepping control, the dynamic surface control, and the recursive sliding mode control together. Theoretical analysis shows that the closed-loop system is stable in the Lyapunov sense. Finally, simulation research is conducted by using the actual data, and results show the validity of the proposed control strategy.