Anti-saturation fault-tolerant adaptive torsional vibration control with fixed-time prescribed performance for rolling mill main drive system

Abstract

An anti-saturation fault-tolerant adaptive torsional vibration control method with fixed-time prescribed performance for the rolling mill main drive system (RMMDS) was investigated, which is affected by control input saturation, actuator faults, sensor measurement errors, and parameter perturbations. First, we gave a continuously differentiable saturation function to approximate the control input saturation characteristic of the RMMDS, translating the saturation characteristic into the matched uncertainty and unknown time-varying gain in the system. Then, an RMMDS mathematical model with unmatched uncertainty and unknown time-varying gain was developed, taking into account the presence of control input saturation, actuator faults, sensor measurement errors, and parameter perturbations. Based on the established mathematical model, an error transformation model of the roll speed tracking was constructed by the equivalent error transformation method. According to the error transformation model, a barrier Lyapunov function and a novel adaptive controller were studied to ensure that the roll speed tracking error always evolves inside a fixed-time asymmetric constraint. Finally, numerical simulations were performed in Matlab/Simulink to verify the effectiveness and superiority of the proposed control method in suppressing the RMMDS torsional vibration.