| 摘要 |
PROBLEM TO BE SOLVED: To realize accurate positioning and reduction of setting time in the positioning control of an ultrasonic motor. SOLUTION: A control unit 40 for positioning and position correction determines that a moving body 24 reaches an aimed position and maintains the position stably in a step 108 as a time point when a standby period t has passed, at a plurality of times during the period t whether or not inversion for position correction is necessary. That is, the reference standby period t is divided into first, second and third divided reference standby periods t1, t2 and t3. A step 104 is a time point when t1 has passed, a step 106 is a time point when t2 has passed, and a step 108 is a time point when t3 has passed. Decision whether or not the inversion for position correction is necessary is performed in the steps 104, 106 and 108. As to the periods, the first is the shortest, the last is the longest, and time intervals of steps between the first and the last are set to be longer in the order. The start of the reference standby period t is a time point when a stop command is generated in a step 102. |
