System and methods for actuation using electro-osmosis

Patent metadata

Field	Value
Publication number	US-9487387-B2
Application number	US-201314422654-A
Country	US
Kind code	B2
Filing date	Aug 20, 2013
Priority date	Aug 20, 2012
Publication date	Nov 8, 2016
Grant date	Nov 8, 2016

Abstract

The invention exploits a widely used device in micro-fluidics, the electro-osmotic pump (EOP), to create very low energy micro-scale and macro-scale mechanical actuators. The EOP uses electrical fields to move naturally occurring charged particles (ions) through a fluid medium. As the ions move in response to the applied field, they drag the (non-charged) fluid along, establishing bulk flow. When confined to a narrow chamber, a pressure gradient can be established. The combination of pressure gradient and flow performs mechanical work. With the use of electro-osmotic pumps, the invention enables actuators to be constructed in a variety of embodiments, including for example, a sheet structure, a piston structure, and a cellular structure to name a few.

First claim

The invention claimed is:

1. A mechanical actuator, comprising
a first flexible sheet including a first top side and a first bottom side, each side coated with a first conductive layer, the first flexible sheet comprising a plurality of first chambers;
a second flexible sheet including a second top side and a second bottom side, each side coated with a second conductive layer, the second flexible sheet comprising a plurality of second chambers;
a third flexible sheet including a third top side and a third bottom side, wherein the third flexible sheet comprises a plurality of third chambers of a honey-comb arrangement;
the second top side of the second flexible sheet is fused to the third bottom side of the third flexible sheet at a plurality of regular intervals and the first bottom side of the first flexible sheet is fused to the third top side of the third flexible sheet at a plurality of regular intervals to obtain an assembled flexible sheet structure including a plurality of assembled chambers;
an outer membrane including a working fluid, wherein the assembled flexible sheet structure is positioned inside the outer membrane to create the mechanical actuator; and
the assembled flexible sheet structure configured to contract and expand to form a linear actuator when a voltage is applied to pump the working fluid across the assembled flexible sheet structure and into the plurality of assembled chambers.

2. The mechanical actuator of claim 1 , wherein the first flexible sheet and the second flexible sheet are fabricated from a polymer.

3. The mechanical actuator of claim 1 , wherein the plurality of assembled chambers are separated by individually addressable permeable conductive layers such that voltage applied to one or more individually addressable permeable layers causes the working fluid to flow from one chamber into an adjacent chamber.

4. The mechanical actuator of claim 3 further comprising an inelastic inner strut positioned within each chamber to bias the contraction and expansion of the chamber.

5. A mechanical actuator, comprising:
a piston including a cylinder and a head with a plurality of perforations;
an enclosed chamber filled with a working fluid, wherein the enclosed chamber includes an aperture through which the piston is positioned within the enclosed chamber;
one or more electrodes on the piston, wherein the one or more electrodes are configured to be charged to create an electric field in order to move the working fluid and actuate the piston.

6. The mechanical actuator of claim 5 , wherein the one or more electrodes are positioned on either side of one or more perforations of the plurality of perforations.

7. The mechanical actuator of claim 6 further comprising one or more conductors that connect the one or more electrodes to an outside surface of the enclosed chamber.

8. The mechanical actuator of claim 5 , wherein the one or more electrodes are positioned at two opposing outside surfaces of the enclosed chamber.

9. The mechanical actuator of claim 5 , further comprising one or more second electrodes positioned at the aperture of the enclosed chamber.

10. A mechanical actuator, comprising
a first flexible sheet including a first top side and a first bottom side, each side coated with a first conductive layer, the first flexible sheet comprising a plurality of first chambers;
a second flexible sheet including a second top side and a second bottom side, each side coated with a second conductive layer, the second flexible sheet comprising a plurality of second chambers;
the second top side of the second flexible sheet is fused to the first bottom side of the first flexible sheet at a plurality of regular intervals to obtain an assembled flexible cellular structure including a plurality of assembled chambers;
a working fluid positioned inside the flexible cellular structure to create the mechanical actuator, wherein the plurality of assembled chambers are separated by individually addressable permeable layers such that voltage applied to one or more individually addressable permeable layers causes the working fluid to flow from one chamber into an adjacent chamber such that select chambers of the plurality are configured to contract and expand.

11. The mechanical actuator of claim 10 , wherein the first flexible sheet and the second flexible sheet are fabricated from a polymer.

12. The mechanical actuator of claim 10 further comprising an inelastic inner strut positioned within each chamber to bias the contraction and expansion of the chamber.

Assignees

• Univ Cornell

Inventors

• Maccurdy Robert
• Lipson Hod

Classifications

• B81B3/0021 Primary

  Transducers for transforming electrical into mechanical energy or vice versa (dynamo-electric machines H02K99/00; electrostatic machines H02N1/00; piezoelectric devices H10N30/00) · CPC title

• B81B5/00

  Devices comprising elements which are movable in relation to each other, e.g. comprising slidable or rotatable elements · CPC title

• B81B2203/04

  Electrodes · CPC title

• F25B41/02

  Mechanical Engineering · mapped topic

• B01L3/502746

  characterised by the means for controlling flow resistance, e.g. flow controllers, baffles or throttle valves · CPC title