随着超声波电机运行时间的增加，其谐振频率会下降，进而使电机速度降低。

As the increase of running time, the resonant frequency of ultrasonic motor will decrease, which then leads to the decrease of speed.

youdao

随着超声波电机运行时间的增加，其谐振频率会下降，进而使电机速度降低。

As the increase of running time, the resonant frequency of ultrasonic motor will decrease, which then leads to the decrease of speed.

youdao