| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem in which it is difficult to hold a plurality of ultrasonic motors at the same speed as a vibration voltage value and a rotating speed value detected from a piezoelectric body are dissociated owing to variation in piezoelectric coefficient value of the piezoelectric body due to temperature variation, pressing force variation with time, etc., and a performance decrease, noise generation, and shortening of a lifetime are thereby inevitable.SOLUTION: A first drive signal or/and a second drive signal have values corrected with values found from characteristics of a first ultrasonic motor detected by making a second ultrasonic motor generate a standing wave and the first ultrasonic motor generate a progressive wave, and characteristics of the second ultrasonic motor detected by making the first ultrasonic motor generate a standing wave and the second ultrasonic motor generate a progressive wave. |
