摘要 |
A technology, wherein unstable operation of the ultrasonic motor is prevented, when the ultrasonic motor is driven at the lower speed out of at least two types of speeds, and life extension is attempted, is disclosed, and according to this invention, when the ultrasonic motor 3 is driven at a comparatively low-speed during normal driving, unstable operation due to driving at a comparatively low-speed can be prevented and life extension can be attempted by driving the ultrasonic motor at a comparatively high-speed every predetermined period of time.
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