Drive control device for an ultrasonic motor
First Claim
1. A drive control device for an ultrasonic motor, in which two AC signals having a fixed phase difference are supplied to two input electrode groups on an electromagnetic energy to mechanical energy conversion element, and which drives a movable element by generating a progressive wave in a fixed element by said electromagnetic energy to mechanical energy conversion element, wherein at least two detector electrodes are provided on said electromagnetic energy to mechanical energy conversion elements, and comprising a frequency band control means which, based upon a phase difference between the output signals from said detector electrodes, performs control so as to bring the frequency of said two AC signals to be within a desired order resonance frequency band among a plurality of resonant frequency bands.
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Abstract
Based upon the output signals from two detector electrodes provided in positions which differ from those of input electrodes on a piezoelectric transducer element, it is detected in what order resonance frequency band the drive frequency of an ultrasonic motor is included, and the drive frequency of the ultrasonic motor is controlled so as to be within a predetermined frequency band.
Further, the resonance frequency band for the ultrasonic motor is switched over to any one of several resonance frequency bands, and, based upon the output signals from the two detector electrodes provided on the piezoelectric transducer element, it is detected in what order resonance frequency band the drive frequency is included, and the drive frequency of the ultrasonic motor is controlled so as to be within the resonance frequency band which has been switched over to.
61 Citations
22 Claims
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1. A drive control device for an ultrasonic motor, in which two AC signals having a fixed phase difference are supplied to two input electrode groups on an electromagnetic energy to mechanical energy conversion element, and which drives a movable element by generating a progressive wave in a fixed element by said electromagnetic energy to mechanical energy conversion element, wherein at least two detector electrodes are provided on said electromagnetic energy to mechanical energy conversion elements, and comprising a frequency band control means which, based upon a phase difference between the output signals from said detector electrodes, performs control so as to bring the frequency of said two AC signals to be within a desired order resonance frequency band among a plurality of resonant frequency bands.
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2. A drive control device for an ultrasonic motor, in which two AC signals having a fixed phase difference are supplied to two input electrode groups on an electromagnetic energy to mechanical energy conversion element, and which drives a movable element by generating a progressive wave in a fixed element by said electromagnetic energy to mechanical energy conversion element, comprising:
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a frequency band control means which, based upon a phase difference between the output signals from at least two detector electrodes provided on said electromagnetic energy to mechanical energy conversion element, performs control so as to bring the frequency of said two AC signals to be within a desired order resonance frequency band among a plurality of resonant frequency bands; and a drive frequency control means which, after the frequency of said two AC signals has reached the frequency of the desired order resonance frequency band, controls said frequency of said two AC signal to be a predetermined drive frequency.
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3. A drive control device for an ultrasonic motor which drives a movable element by generating a progressive wave in a fixed element by an electromagnetic energy to mechanical energy conversion element, comprising:
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(a) a frequency setting means which sets the drive frequency of said ultrasonic motor; (b) a resonance order detection means which detects in which order of resonance frequency band the drive frequency of said ultrasonic motor lies, based upon the output signals from at least two detector electrodes which are provided on said electromagnetic energy to mechanical energy conversion element; (c) a frequency band control means which controls said frequency setting means so as to bring the drive frequency of said ultrasonic motor to the frequency of a predetermined order resonance frequency band, based upon the order of resonance frequency band detected by said resonance order detection means; (d) a phase shifting oscillator means, which generates two AC signals with the drive frequency set by said frequency setting means, having a fixed phase difference between them; and
;(e) a power amplifier means which amplifies said two AC signals which are generated by said phase shifting oscillator means, and supplies them to two input electrode groups which are provided on said electromagnetic energy to mechanical energy conversion element. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10)
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11. A drive control device for an ultrasonic motor which drives a movable element by generating a progressive wave in a fixed element by an electromagnetic energy to mechanical energy conversion element, comprising:
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(a) a frequency setting means which sets the drive frequency of said ultrasonic motor; (b) a frequency band switchover means which switches over the resonance frequency band of said ultrasonic motor to any one of a plurality of resonance frequency bands; (c) a resonance order detection means which detects in which order of resonance frequency band the drive frequency of said ultrasonic motor lies, based upon the output signals from at least two detector electrodes which are provided on said electromagnetic energy to mechanical energy conversion element; (d) a frequency band control means which controls said frequency setting means so as to bring the drive frequency of said ultrasonic motor to the frequency of the resonance frequency band switched over to by said frequency band switchover means, based upon the order of resonance frequency band detected by said resonance order detection means; (e) a phase shifting oscillator means which generates two AC signals with the drive frequency set by said frequency setting means, having a fixed phase difference between them; and
;(f) a power amplifier means which amplifies said two AC signals which are generated by said phase shifting oscillator means, and supplies them to two input electrode groups which are provided on said electromagnetic energy to mechanical energy conversion element. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A drive control device for an ultrasonic motor, in which two AC drive signals having a fixed phase difference are supplied to two input electrode groups on an electromagnetic energy to mechanical energy conversion element, and which drives a movable element by generating a progressive wave in a fixed element by said electromagnetic energy to mechanical energy conversion element, comprising:
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a resonance order detection means that detects the order of the resonance frequency band of the AC drive signals based upon output signals from at least two detector electrodes that are provided on said electromagnetic energy to mechanical energy conversion element; and a frequency band control means that controls the frequency of said two AC drive signals to be within a predetermined order resonance frequency band, based upon the order of the resonance frequency band of the AC drive signals detected by said resonance order detection means.
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22. A drive control device for an ultrasonic motor, in which two AC drive signals having a fixed phase difference are supplied to two input electrode groups on an electromagnetic energy to mechanical energy conversion element, and which drives a movable element by generating a progressive wave in a fixed element by said electromagnetic energy to mechanical energy conversion element, comprising:
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a resonance order detection means that detects the order of the resonance frequency band of the AC drive signals based upon output signals from at least two detector electrodes that are provided on said electromagnetic energy to mechanical energy conversion element; a frequency band control means that controls the frequency of said two AC drive signals to be within a predetermined order resonance frequency band based upon the order of the resonance frequency band of the AC drive signals detected by said resonance order detection means; and a drive frequency control means which, after the frequency of said two AC drive signals has reached the frequency of the predetermined order resonance frequency band, controls said frequency of said two AC drive signals to be a predetermined drive frequency.
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Specification