PURPOSE: To prevent the generation of abnormal sound and control the driving of an ultrasonic motor properly by a method wherein only a signal, having a frequency obtained by multiplying or dividing a resonance frequency, is extracted and the driving frequency of the motor is controlled based on the extracted signal.
CONSTITUTION: A microcomputer(MC) 3 reads an output data from an A/D converter 25, determines the driving frequency of an ultrasonic motor in accordance with the read data, outputs a data in reference to the driving frequency to a D/A converter 5 and drives the ultrasonic motor. The driving frequency of a voltage, impressed on a piezo-electric body, is controlled by a method wherein the oscillating condition of the piezo-electric body is detected by an electrode 1c and multiplied or divided resonance frequency is extracted by a band pass filter 21 while the output value is controlled so as to be lower than a predetermined value. According to this method, the driving frequency may be controlled without generating any abnormal sound even when temperature change or time aging is generated and a load is fluctuated.
| JP2007159244 | DRIVE UNIT AND ELECTRONIC APPARATUS |
| JP2005141208 | DIFFRACTIVE THIN-FILM PIEZOELECTRIC MICROMIRROR AND METHOD OF PRODUCING THE SAME |
| WO/2004/020134 | TOOL |
ICHIKAWA SATOSHI
TODA MASAYUKI
SHIBUYA HIDEYUKI
OKAMOTO TAKAFUMI
