To provide an apparatus for monitoring ultrasonic motor state which can issue warnings in an audible manner the generation of heat which impedes the stable driving of the ultrasonic motor or other unstable phenomena.
The ultrasonic motor stator monitoring apparatus includes an acoustic data read-out controller 14 for reading the acoustic data regarding warning sound from an acoustic data storage unit 13, when the value of physical quantity measured by each physical quantity sensor, such as a current sensor 3, a temperature sensor 4, a rotational speed sensor 5, a rotation angle sensor 6, etc. exceeds threshold, and an amplitude modulation circuit 16 for obtaining a modulated wave signal, by modulating the amplitude of a driving ac voltage, according to acoustic signal corresponding to the acoustic data. When the modulated wave signal is applied to the piezoelectric vibrator (first to third system piezoelectric vibrators 21-23) of an ultrasonic motor 2, ultrasonic waves are emitted, the warning sound demodulated directly from the modulated wave signal is made to emit to the ultrasonic motor 2 itself by the self-demodulation phenomenon of the ultrasonic wave.
| JPH04360133 | CAMERA |
| JPH06104503 | BIMORPH PIEZOELECTRIC ACTUATOR |
AOKI SHIGEAKI
HIRAHARA TATSUYA
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