Driving control device for vibration wave motor

DETAILED DESCRIPTION An object of the present invention is to restore ultrasonic motor which has gone into an vibration diversion state to a normal vibration state speedily and easily without releasing the load.
Another object of the invention is to improve the starting characteristics of the ultrasonic motor without a time lag at the starting time.
Referring to FIG.
1 which illustrates one embodiment, the driving control circuit of the invention is used to control the driving of an ultrasonic motor MT equipped with a stator that generates traveling vibration waves in an elastic member by the excitation of a piezoelectric member and a rotor which is pressed into contact with said stator and is driven by the traveling vibration waves.
This driving control circuit has a power supply circuit 30 for applying at least one pair of out-of-phase frequency voltages to excite the piezoelectric member.
A judgment circuit 20 for judging the vibration diversion state of the stator is also provided.
If the motor is judged to be in the vibration diversion state by the judgment circuit, the power supply circuit raises the voltage magnitude of the pair of frequency voltages higher than that at normal times.
As a result of this, the above-mentioned purposes are achieved.
It is desirable to arrange the vibration diversion state judgment means 20 in such a way that a frequency voltage and a monitor voltage that are applied to a piezoelectric member 1b are detected by applied voltage detection means for detecting the frequency voltage applied to the piezoelectric member 1b and monitor voltage detection means for detecting a monitor voltage generated as a piezoelectric member 1b changes its shape, the phase differences between them are detected by phase difference detection means, and if the phase difference is detected as being out of a predetermined range, the motor is judged to be a vibration diversion state.
When the motor is judged to be the vibration diversion state, the input voltage to the piezoelectric member is made higher than that at normal times