Angular speed control of torque motor based on fractional order ADRC

This study addresses the limitations inherent in the traditional Extended State Observer (ESO) within the Active Disturbance Rejection Control (ADRC) framework, specifically targeting issues such as large observation errors, low accuracy, and significant overshoot in estimating the total angular velocity perturbation of torque motors. To overcome these challenges, a Fractional-Order Extended State Observer (FOESO) is proposed. This observer utilizes a novel nonlinear function with improved smoothness and continuity near the origin to enhance observation precision. Furthermore, Repetitive Control (RC), based on the internal model principle, is introduced to mitigate periodic errors and further refine accuracy. By integrating the high-precision estimation of the FOESO with the periodic disturbance rejection of the RC, a composite strategy termed Repetitive Control and Fractional-Order Active Disturbance Rejection Control (RC-FOADRC) is developed. This strategy upgrades the conventional ADRC architecture to achieve stable, high-precision system state observation with minimal error. Experimental analysis targeting the angular velocity of a torque motor validates the effectiveness and feasibility of the proposed RC-FOADRC strategy compared to traditional methods.