Extended-state-observer-based robust torsional vibration suppression for rolling mill main drive system with input saturation

A robust torsional vibration suppression strategy is proposed for the main drive system of the rolling mill subject to uncertainties, disturbances and input saturation. With given model information incorporated into observer design, an extended state observer that relies only on roller speed measurements is developed to estimate the system states and lumped uncertainties of the rolling mill main drive system. To handle the motor torque saturation, an auxiliary signal system with the same order as the plant is constructed. The error between the control input and plant input is taken as the input of the constructed auxiliary system, and a number of signals are generated to compensate for the effect of the motor torque saturation. Furthermore, a robust output feedback controller is introduced to obtain better transient and steady-state performance of the rolling mill main drive system and the stability of the closed-loop system is strictly proved via Lyapunov theory. Finally, comparative simulations are performed to verify the effectiveness and superiority of the proposed control strategy.