Control device for ultrasonic motor
First Claim
1. A control device for an ultrasonic motor comprising:
- an oscillator for generating drive signals of a resonant frequency of an ultrasonic motor;
drive signal restricting means for turning on and off said drive signals at a fixed duty ratio;
a counter in which counted results of the counter are incremented by a first pulse signal whose frequency increases as a target speed of the ultrasonic motor increases, and in which the counted results are decremented by a second pulse signal whose frequency increases as a travel speed of said ultrasonic motor increases; and
duty ratio setting means for causing said duty ratio to increase as the counted results of said counter increase.
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Accused Products
Abstract
A control device for an ultrasonic motor which is suitable for use in controlling the speed of the ultrasonic motor includes an oscillator for generating drive signals of a resonant frequency of the ultrasonic motor; and a drive signal restricting device for turning on and off the drive signals at a fixed duty ratio. The control device further includes a counter in which counted results of the counter are incremented by a first pulse signal whose frequency increases as a target speed of the ultrasonic motor increases, and in which the counted results are decremented by a second pulse signal whose frequency increases as a travel speed of the ultrasonic motor increases; and a duty ratio setting device for causing the duty ratio to increase as the counted results of the counter increase.
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Citations
1 Claim
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1. A control device for an ultrasonic motor comprising:
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an oscillator for generating drive signals of a resonant frequency of an ultrasonic motor; drive signal restricting means for turning on and off said drive signals at a fixed duty ratio; a counter in which counted results of the counter are incremented by a first pulse signal whose frequency increases as a target speed of the ultrasonic motor increases, and in which the counted results are decremented by a second pulse signal whose frequency increases as a travel speed of said ultrasonic motor increases; and duty ratio setting means for causing said duty ratio to increase as the counted results of said counter increase.
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Specification
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- Resources
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Current AssigneeALPS Electric Company Limited (Alps Alpine Co., Ltd.)
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Original AssigneeALPS Electric Company Limited (Alps Alpine Co., Ltd.)
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InventorsTanaka, Masayuki
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Primary Examiner(s)Budd, Mark O.
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Application NumberUS07/665,503Time in Patent Office657 DaysField of Search314/316, 314/317, 314/323, 318/116, 318/135US Class Current310/316.02CPC Class CodesH02N 2/003 using longitudinal or radia...H02N 2/026 by pressing one or more vib...H02N 2/062 Small signal circuits; Mean...
