Vibration actuator and method of control
First Claim
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1. A vibration actuator, comprising:
- an elastic body;
vibration element joined to the elastic body;
drive system to output a drive signal to the vibration element; and
a relative motion member in contact with a driving surface of the elastic body and which is driven by the driving surface,wherein the drive system excites the vibration element with a first drive signal and a second drive signal to respectively produce a first vibration mode and a second vibration mode, wherein displacement of the driving surface occurs in a direction about the same as the drive direction of the relative motion member in the first vibration mode, and displacement of the driving surface occurs in a direction intersecting the driving surface in the second vibration mode causing relative motion between the vibration element and the relative motion member, and the drive system controls a voltage of at least one of the first drive signal and the second drive signal to independently adjust the voltage of at least one of the first drive signal and the second drive signal.
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Abstract
An ultrasonic actuator which can be accurately controlled at low drive speeds and with reduction in speed irregularities at low speeds. The ultrasonic actuator includes elastic bodies joined to electromechanical conversion elements and a relative motion member in compressive contact with the elastic bodies. A control system outputs first and second drive signals to the electromechanical conversion elements to control the vibration actuator. The control system directly controls the voltage of the first drive signal to independently control the respective voltages of the first drive signal and a second drive signal.
20 Citations
23 Claims
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1. A vibration actuator, comprising:
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an elastic body; vibration element joined to the elastic body; drive system to output a drive signal to the vibration element; and a relative motion member in contact with a driving surface of the elastic body and which is driven by the driving surface, wherein the drive system excites the vibration element with a first drive signal and a second drive signal to respectively produce a first vibration mode and a second vibration mode, wherein displacement of the driving surface occurs in a direction about the same as the drive direction of the relative motion member in the first vibration mode, and displacement of the driving surface occurs in a direction intersecting the driving surface in the second vibration mode causing relative motion between the vibration element and the relative motion member, and the drive system controls a voltage of at least one of the first drive signal and the second drive signal to independently adjust the voltage of at least one of the first drive signal and the second drive signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of controlling a vibration actuator including an elastic body, a vibration element joined to the elastic body and a relative motion member which is driven by a driving surface of the elastic body, comprising the steps of:
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generating a first drive signal to produce a first vibration mode causing displacement of the driving surface of the elastic body in about the same direction as the relative motion member is driven; generating a second drive signal to produce a second vibration mode causing displacement of the driving surface of the elastic body in a direction which intersects the driving surface of the elastic body; and independently adjusting a voltage of at least one of the first drive signal and the second drive signal to produce relative motion between the elastic body and relative motion member in accordance with the first and second vibration modes. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23)
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Specification