SELF-SENSING DIELECTRIC ACTUATOR SYSTEM

• US 20100164324A1
• Filed: 07/22/2008
• Published: 07/01/2010
• Est. Priority Date: 07/23/2007
• Status: Abandoned Application

• Current Assignee: Board of Regents Nevada System of Higher Education (State of Nevada)
• Original Assignee: Board of Regents Nevada System of Higher Education (State of Nevada)
• Inventors: Kim, Kwang J., Jung, Kwangmok
• Application Number:
  US12/670,362
• Publication Number:
  US 20100164324A1
• Time in Patent Office: Days
• US Class Current: 310/318
• CPC Class Codes: H01G 5/16 using variation of distance between electrodes
• CPC Class Codes: H02N 1/006 of the gap-closing type H02N1/004 takes precedence
• CPC Class Codes: H10N 30/802 Drive or control circuitry or methods for piezoelectric or electrostrictive devices not otherwise provided for

Abstract

A self-sensing dielectric actuator system. The system has a deformable dielectric material between two electrodes. A relatively low frequency actuating signal is applied to the electrodes and thereby causes the dielectric material to deform, moving at least one electrode. A relatively high frequency sensing signal applied across the electrodes indicates how far the electrode has moved. The system may be calibrated by using a laser or other sensor to mechanically measure the amount of movement. An object may be displaced a desired distance by coupling the object to the electrode and using the sensing signal to measure how far the object has moved.

Claims

1. A self-sensing dielectric actuator system comprising:

a deformable first electrode;

a second electrode spaced apart from the first electrode;

a dielectric material disposed between the electrodes;

an actuating signal source configured to apply an electric potential across the electrodes and thereby cause the dielectric material to deform the first electrode;

a sensing signal source configured to apply a sensing signal across the electrodes; and

a sensing element from which any change in the sensing signal caused by a deformation of the first electrode may be measured.

2. A system as in claim 1 wherein the sensor comprises an impedance element in electrical communication with the sensing signal source.

3. A system as in claim 1 wherein the sensor comprises an oscilloscope in electrical communication with the sensing signal source.

4. A system as in claim 1 wherein the sensor comprises a resistor in series with the sensing signal source and an oscilloscope that measures the sensing signal flow through the resistor.

5. A system as in claim 1 and further comprising a mixer that receives the sensing signal from the sensing signal source and the actuating signal from the actuating signal source and combines them for application to the electrodes.

6. A system as in claim 1 wherein the second electrode is deformable.

7. A system as in claim 1 wherein the electrodes comprise parallel plates.

8. A system as in claim 7 wherein the electrodes comprise generally disc-shaped coatings on opposite sides of the dielectric material and each electrode has an elongated terminal extending radially therefrom.

9. A system as in claim 1 and further comprising:

a measurement system that provides a measurement signal indicative of actual deformation of the first electrode; and

a controller responsive to the measurement signal and the sensing signal to provide a calibration of the sensing signal with respect to actual deformation of the first electrode.

10. A system as in claim 9 wherein the measurement system comprises a laser measurement system.

11. A method of sensing motion of an actuator of the kind having a deformable dielectric between two electrodes, the method comprising:

applying an actuating signal across the dielectric;

applying a sensing signal across the dielectric; and

measuring any change in the sensing signal as the dielectric deforms under influence of the actuating signal.

12. A method as in claim 11 wherein applying a sensing signal comprises applying an alternating-current signal.

13. A method as in claim 11 wherein measuring a change in the sensing signal comprises measuring the sensing signal across an impedance element.

14. A method as in claim 11 and further comprising:

measuring a magnitude of the deformation of the dielectric; and

calibrating the measured change in the semsing signal according to the measured magnitude.

15. A method as in claim 14 wherein measuring a magnitude of the deformation comprises sensing the magnitude with a laser sensor.

16. A method of mechanically displacing an object a desired distance comprising:

coupling the object to a deformable first electrode;

applying an actuating signal across the first electrode and a second electrodes to generate an electric field across a deformable dielectric disposed between the electrodes;

applying a sensing signal across the dielectric;

measuring any change in the sensing signal as the dielectric deforms under influence of the actuating signal; and

adjusting the actuating signal according to the measured change in the displacement signal to displace the object a desired distance.

17. A method as in claim 16 wherein applying a sensing signal comprises applying an alternating-current signal.

18. A method as in claim 16 wherein measuring a change in the sensing signal comprises measuring the sensing signal across an impedance element.

19. A method as in claim 16 and further comprising:

measuring a magnitude of the deformation of the dielectric; and

calibrating the measured change in the sensing signal according to the measured magnitude.

20. A method as in claim 19 wherein measuring a magnitude of the deformation comprises sensing the magnitude with a laser sensor.