Active disturbance rejection control for vibration displacement tracking system of continuous casting mold driven by servo motor

Active disturbance rejection control (ADRC) is applied in this paper to solve the problems of time-varying load torque disturbance, reduction ratio uncertainty and the initial deviation of the eccentric shaft mechanical zero, which exist in the continuous casting mold vibration displacement system driven by servo motor. ADRC consists of three parts: tracking differentiator (TD), extended state observer (ESO) and nonlinear state error feedback (NLSEF). TD is responsible for the arrangement of the transition process of eccentric shaft angular displacement and extracts its differential signal, which makes eccentric shaft angular displacement change gently. To improve the tracking accuracy, a modified ESO is designed to estimate and compensate comprehensive disturbance of the control system, which enhances system anti-disturbance ability, And NLSEF is then developed to improve the rapidity and stability of the control system. Finally, the simulation results are given to show that ADRC has the characteristics of fast response, high accuracy and strong robustness against the internal and external disturbances in the control system.