| 摘要 |
PURPOSE:To enable stabilized drive control by detecting the phase difference between the input and output of an inductive element and controlling a frequency signal according to the magnitude of thus detected phase difference. CONSTITUTION:Upon start of driving of a ultrasonic motor 8, a phase difference detecting circuit 7 detects the phase difference between the input and output signals of an inductive element 6 and produces an output voltage corresponding to the magnitude of thus detected phase difference. Frequency signal is then controlled based on thus detected phase difference thus performing drive control of the ultrasonic motor 8. Since the driving frequency for the ultrasonic motor 8 is feedback controlled so that the phase difference is settled to a set value, a stabilized driving operation and a desired driving speed can be achieved. |
