| 摘要 |
<P>PROBLEM TO BE SOLVED: To materialize the power-saved drive of an ultrasonic motor driving unit by searching the drive frequency to lessen a drive current most while detecting the drive current, and fixing the drive frequency to the frequency thereby controlling it. <P>SOLUTION: This device has a secondary voltage detecting means 618 which detects the voltage of power supplied from a secondary battery, a current detecting means 614 which detects the drive current of an ultrasonic motor 602, a frequency control means 616 which controls the drive frequency to be applied to the ultrasonic motor 602, and a drive means 612 which drives the ultrasonic motor 602, based on the command of the frequency control means 616. In this case, it is driven in a power saving mode where power consumption becomes smallest when the voltage detected by the secondary battery voltage detecting means 618 is smaller than a specified value. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
