| 摘要 |
PROBLEM TO BE SOLVED: To provide an improved ultrasonic motor control circuit which controls driving signal frequency, thus stabilizing ultrasonic motor operation. SOLUTION: This ultrasonic motor control circuit includes drives 130/140 which drive an ultrasonic motor 100 corresponding to a drive signal with a predetermined frequency, a detector 160 which detects the driving current flowing through the driving ultrasonic motor 100 and output current data I, and controllers 171-174 which output frequency data F based on the current data I and control the drive signal frequency to stabilize the driving current. These controllers determine a deviation ΔI between the detected current data I and predetermined reference current data I0. Next, they determine a difference ΔF corresponding to ΔI, and further, add the difference Δ F to the frequency data F to update the frequency data F. The renewed frequency data F controls the frequency of driving current, thus stabilizing the driving current. |
