Rotational sensors including ionic liquids and methods of making and using the same

Patent metadata

Field	Value
Publication number	US-10082391-B2
Application number	US-201615292869-A
Country	US
Kind code	B2
Filing date	Oct 13, 2016
Priority date	Oct 13, 2015
Publication date	Sep 25, 2018
Grant date	Sep 25, 2018

Abstract

Sensors for measuring rotation about an axis are disclosed, along with methods of making and using the same. The sensors can utilize ionic liquids and electrodes that provide a unique electrical signal at each angle of rotation about an axis. The sensors can include a solid structure with a channel that circumnavigates the axis, electrodes disposed within the channel, and an ionic liquid positioned within the channel.

First claim

We claim:

1. A sensor for measuring rotation about an axis, the sensor comprising:
a solid structure comprising a channel that circumnavigates the axis;
a first anode and a first cathode disposed within the channel;
an ionic liquid positioned within the channel, the ionic liquid contacting the first anode and the first cathode when the sensor is positioned such that the axis is at an angle of between 1° and 179° relative to a gravitational axis representing the force of gravity; and
a controller coupled to the first anode and the first cathode, the controller configured to apply a first non-zero voltage between the first anode and the first cathode, the controller configured to communicate a rotation sense signal corresponding to a rotation about the axis, wherein the first anode and the first cathode are configured to provide a unique rotation sense signal value at each angle of rotation about the axis.

2. The sensor of claim 1 , wherein the first anode and/or the first cathode is dimensioned to provide a unique cross-section of coverage by the ionic liquid at each angle of rotation about the axis.

3. The sensor of claim 1 , wherein the first anode and/or the first cathode has a unique width at each angular position relative to the axis.

4. The sensor of claim 1 , wherein the first anode and/or the first cathode has a width that changes as a function of angular position relative to the axis.

5. The sensor of claim 4 , wherein the width has a unique width value at each angular position relative to the axis.

6. The sensor of claim 1 , wherein a distance between the first anode and the first cathode changes as a function of angular position relative to the axis.

7. The sensor of claim 6 , wherein the distance between the first anode and the first cathode has a unique distance value at each angular position relative to the axis.

8. The sensor of claim 1 , wherein the channel has a circular shape in a plane normal to the axis.

9. The sensor of claim 1 , wherein the channel has an internal volume of between 0.001 μL and 0.05 mL.

10. The sensor of claim 1 , wherein the solid structure is monolithic.

11. The sensor of claim 1 , wherein the solid structure comprises two or more sub-structures.

12. The sensor of claim 11 , wherein the two or more sub-structures comprise a substrate and a capping structure.

13. The sensor of claim 12 , wherein the substrate and the capping structure are sealed to one another and the channel is formed between the substrate and the capping structure.

14. The sensor of claim 1 , wherein the ionic liquid is present in a volume of between 1% and 50% of an internal volume of the channel.

15. The sensor of claim 1 , wherein the ionic liquid comprises a material selected from the group consisting of a metal halide, a compound comprising a metal and a chalcogen, and combinations thereof.

16. The sensor of claim 1 , wherein the ionic liquid comprises a material selected from the group consisting of potassium iodide, sodium iodide, lithium iodide, 1-butyl-3-methyl-imidazolium iodide, ethylammonium nitrate, and combinations thereof.

17. The sensor of claim 1 , the solid structure further comprising a valve through which the ionic liquid can be added to or removed from the channel.

18. A method of measuring rotation of an object about an axis using a sensor, the sensor comprising a solid structure comprising a channel that circumnavigates the axis, the sensor comprising a first anode and a first cathode disposed within the channel, the sensor comprising an ionic liquid positioned within the channel, the ionic liquid contacting the first anode and the first cathode when the sensor is positioned such that the axis is at an angle of between 1° and 179° relative to a gravitational axis representing the force of gravity, the sensor comprising a controller coupled to the first anode and the first cathode, the controller configured to apply a first non-zero voltage between the first anode and the first cathode, the controller configured to communicate a rotation sense signal corresponding to a rotation about the axis, wherein the first anode and the first cathode are configured to provide a unique rotation sense signal value at each angle of rotation about the axis, the method comprising:
affixing the sensor to the object such that the angle is between 1° and 179° relative to the gravitational axis; and
measuring the rotation sense signal.

19. A method of making a sensor, the method comprising:
forming a solid structure comprising a channel that circumnavigates an axis;
positioning a first anode and a first cathode within the channel; and
introducing an ionic liquid to the channel, the ionic liquid contacting the first anode and the first cathode when the sensor is positioned such that the axis is at an angle of between 1° and 179° relative to a gravitational axis representing the force of gravity.

20. The method of claim 19 , wherein forming the solid structure comprising the channel that circumnavigates the axis comprises bonding a capping layer comprising the channel to a surface of a substrate, and wherein positioning the first anode and the first cathode within the channel comprises depositing, prior to the bonding, the first anode and the first cathode onto the surface of the substrate, wherein the bonding is configured to position the first anode and the first cathode within the channel.

Assignees

• Yu Hongyu
• Liang Mengbing
• Univ Arizona State

Inventors

• Yu Hongyu
• Liang Mengbing

Classifications

• G01B13/18

  for measuring angles or tapers; for testing the alignment of axes · CPC title

• G01C2009/182

  conductive · CPC title

• G01C9/18 Primary

  by using liquids · CPC title

• G01D5/16

  by varying resistance · CPC title