Two-Phase Stator Vibration Amplitude Compensation of Traveling-Wave Ultrasonic Motor

The consistency of the two-phase mode responses is essential to ensure mechanical performance and stability traveling-wave ultrasonic motors. Due asymmetry stator, inevitable manufacturing errors, or imbalance excitation voltages, amplitudes standing waves cannot be exactly same, resulting in unstable operating USM. To improve motor decrease velocity fluctuation, a closed-loop control scheme considering compensation based on vibration amplitude stator proposed. This implemented under framework amplitude-based parallel resonance frequency tracking (VCBVF). Based relationship between (SVA), signals are adjusted individually simultaneously. Compared with single-phase feedback VCBVF scheme, experimental results show that proposed can reduce overshoot from 17.50% 6.90% fluctuations 7.69 rpm 2.40 rpm, different load torques. compensate for electrical inconsistency output power operation various conditions.