Fuzzy Iterative Learning Control of Ring Permanent Magnet Torque Motor

Torque pulsations exist in ring permanent torque motors, which seriously degrade the drive performance of system at low speeds. In view of the periodic nature of torque ripple, adopt fuzzy iterative learning control (F-ILC) controller to minimize the torque ripple. It records the torque error and the compensating reference current of last cycle to update the compensating reference current of this cycle. F-ILC controller tune the learning gain according to the magnitude and the change of the torque error, so as to improve the convergent speed of learning controller and reduce the steady-state torque error. The prerequisite for the proposed F-ILC controller is the torque error information, so a disturbance observer is designed. Simulation results show significant improvements in the steady-state torque response and the effectiveness in minimizing torque ripples.