| 摘要 |
PROBLEM TO BE SOLVED: To stabilize the operation of an ultrasonic motor by controlling driving signal frequency. SOLUTION: This ultrasonic motor control circuit includes drives 110 to 140 which drive an ultrasonic motor 100 in accordance with a driving signal with predetermined frequency, detectors 150/160 which detect the driving current flowing through the driving ultrasonic motor 100 and output the current data, and a controller 170 which controls the driving signal frequency by outputting frequency data based on the current data. The controller 170 stores the past current data, determines frequency data comparing the present current data with the past current data, and makes the driving frequency follow the driving current based on their magnitude relation. The controller 170 increases the frequency data if the present current data goes beyond the predetermined deadband with i1 to i2, or decreases the frequency data if the present current data goes below the past current data below the deadband. |
