Repetitive control for vibration reduction of 3-phase HB-type stepping motor utilizing accelerometer and Fourier transformer

In this paper, the authors propose the repetitive control method using an accelerometer to reduce the vibration of the 3-phase hybrid-type (HB) stepping motor with cogging torque. A mechanical system, where the accelerometer is installed on the motor or load frame to detect the vibration due to the torque ripple of the motor, is constructed. Because the torque vibration periodically varies due to cogging torque, the repetitive control is effective for reduction of the vibration. Approximate analysis is preformed to study the stability of the repetitive control system. Another algorithm which is called feedforward control method is applied to the operating point changed by reference frequency in steady-state. Compensation signal for the new operating point will be generated from both amplitude and phase compensation data by repetitive control utilizing the linear interpolation method. The effectiveness of the proposed method is confirmed by experimental results.