149 20110518 Dielectric Elastomer

8/3/2019 149 20110518 Dielectric Elastomer

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NTU Nano-BioMEMS Group-2-

C. L. Kuo, NTU ESOE

Outline

Introduction

A Soft and dexterous motor

- Abstract- Rotary motion

- Result

- Conclusion Application


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C. L. Kuo, NTU ESOE

Dielectric elastomers (DEs) are smart material systems which produce

large strains (up to 300%) and belong to the group of electroactive

polymers(EAP). Based on their simple working principle dielectric elastomer

actuators (DEA) transform electric energy directly into mechanical work. DEare lightweight, have a high elastic energy density and are investigated since

the late 90s. Many potential applications exist as prototypes. Every year in

spring a SPIE conference takes place in San Diego where the newest research

results concerning DEA are exchanged.

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From Wikipedia

Dielectric elastomers (1)
http://en.wikipedia.org/wiki/Smart_materialhttp://en.wikipedia.org/wiki/Strain_(materials_science)http://en.wikipedia.org/wiki/Electroactive_polymershttp://en.wikipedia.org/wiki/Electroactive_polymershttp://en.wikipedia.org/wiki/Electroactive_polymershttp://en.wikipedia.org/wiki/Electroactive_polymershttp://en.wikipedia.org/wiki/Electroactive_polymershttp://en.wikipedia.org/wiki/Strain_(materials_science)http://en.wikipedia.org/wiki/Smart_materialhttp://en.wikipedia.org/wiki/Smart_materialhttp://en.wikipedia.org/wiki/Smart_material


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C. L. Kuo, NTU ESOE

Dielectric elastomers (2)

Ref. 2003.11


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C. L. Kuo, NTU ESOE

Abstract

This paper present a soft, bearing-free artificial muscle

motor that can't only turn a shaft but also reposition it

through a flexible gear.

One actuator technology with performance metrics similar

to natural muscle is the dielectric elastomer actuator(DEA).

When a voltage is applied, the charge accumulating on the

electrode faces gives rise to an electrostatic Maxwell

pressure that results in out-of-plane compression and in-

plane expansion, and that can produce active strains

greater than 30%.


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8/16NTU Nano-BioMEMS Group-8-

C. L. Kuo, NTU ESOE

Rubbery motor creates rotary motion (1)

A photo showing two membrane motors supporting a single

shaft. Actuation of electroded zones in the top of the left hand

side membrane and bottom of the right hand membrane (mode

III) repositioned and changed the angle of the shaft.



C. L. Kuo, NTU ESOE

Rubbery motor creates rotary motion (2)



C. L. Kuo, NTU ESOE

The rotational speed reduced with rising actuation frequency

The actuation frequency of the wave form, fa, started at 0.4 Hz

and was increased in 0.4 Hz steps up to 3.2 Hz. The voltage

wave form had a lower bound of 0, 500, or 1000 V and an upper

bound of 2500 V.

Above 2.2 Hz the rotor speed reduced. Increasing the lower

voltage limit also reduced the shaft speed, providing a

mechanism for electroactive gear change.



C. L. Kuo, NTU ESOE

Conclusion

The performance of the DE membrane motor could be

improved with the substitution of a less viscoelastic

elastomer. One material commonly used for DE artificial

muscles is silicone.

Another way to improve the motor is to use lower voltages.

The Maxwell pressure on the membrane is proportional to

the dielectric constant and the square of the electric field.

Using multiple stacked layers of membrane could also be used

to boost torque.



C. L. Kuo, NTU ESOE

V

Voltage off Voltage on

V

Applications (1)



C. L. Kuo, NTU ESOE

Thin Film Actuators

Voltage off

Voltage on

Applications (2)

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C. L. Kuo, NTU ESOE

Applications (3)

Linear actuators Bending rolls

Push-pull actuators

Speaker

Pump

Sensors

Generator

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C. L. Kuo, NTU ESOE

Dielectric elastomer minimum energy structure serpentine

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16/16NTU Nano BioMEMS Group-16-

C. L. Kuo, NTU ESOE

Thank you for your attention!

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149 20110518 Dielectric Elastomer