Torque Ripple Minimization of Reaction Flywheel Based on Linear Extended State Observer

In spacecraft attitude control, the torque ripple generated by the reaction flywheel can significantly reduce the attitude control accuracy and even affect the attitude stability. This paper focuses on the suppression of harmonic disturbances in the speed and control torque of reaction flywheels. A composite controller based on a linear extended state observer (LESO) and proportional-integral-resonant (PIR) is proposed to improve the accuracy of the output control torque by suppressing speed fluctuations. First, PIR controllers are designed for both the speed and the current loops to suppress harmonic disturbances in the speed loop and enhance the harmonic tracking capability of the current loop. Then, LESO is added to the speed loop to observe the speed and the lumped disturbance, and the observed disturbances are used for feed-forward compensation. Simulation and experimental results show that the proposed method can effectively reduce speed ripple and improve the output torque accuracy of the reaction wheel.