Resistive-capacitive deformation sensor

Patent metadata

Field	Value
Publication number	US-11015989-B2
Application number	US-201916671000-A
Country	US
Kind code	B2
Filing date	Oct 31, 2019
Priority date	Sep 2, 2015
Publication date	May 25, 2021
Grant date	May 25, 2021

Abstract

A deformation sensing apparatus comprises an elastic substrate, a first strain-gauge element formed on a first surface of the elastic substrate, and configured to output a first signal in response to a strain applied in a first direction, and a second strain-gauge element formed on a second surface of the elastic substrate opposite to the first surface, and configured to output a second signal in response to a strain applied in the same first direction.

First claim

What is claimed is:

1. An apparatus comprising:
a first strain-gauge element coupled to a substrate and configured to output a first signal indicative of a resistance of the first strain-gauge element, wherein the first signal is measurable across a first terminal and a second terminal of the first strain-gauge element; and
a second strain-gauge element coupled to the substrate and configured to output a second signal indicative of a resistance of the second strain-gauge element,
wherein the apparatus is configured to output a third signal indicative of a capacitance measurable between a terminal of the first strain-gauge element and a terminal of the second strain-gauge element.

2. The apparatus of claim 1 , wherein the first strain-gauge element is on a first portion of the substrate, and wherein the second strain-gauge element is on a second portion of the substrate.

3. The apparatus of claim 2 , wherein the first portion of the substrate is a top portion of the substrate and the second portion of the substrate is a bottom portion of the substrate.

4. The apparatus of claim 1 , wherein:
the second strain-gauge element has a third terminal and a fourth terminal; and
the second signal is measurable across the third and fourth terminals of the second strain-gauge element.

5. The apparatus of claim 1 , wherein the substrate comprises a flexible, electrically-insulating dielectric material.

6. The apparatus of claim 1 , further comprising:
a measurement circuit configured to measure the first signal from the first strain-gauge element and the second signal from the second strain-gauge element in response to an applied deformation.

7. The apparatus of claim 1 , wherein:
the first strain-gauge element is configured to output the first signal in response to a strain applied in a first direction; and
the second strain-gauge element is configured to output the second signal in response to a strain applied in a second direction.

8. The apparatus of claim 1 , wherein each of the first and second strain-gauge elements has a horse-shoe shape comprising an arcuate head and a pair of elongate leads extending from ends of the arcuate head.

9. The apparatus of claim 1 , further comprising:
a deformation analyzer configured to compute a measure of stretch deformation and a measure of flex deformation of the apparatus, based on the first signal from the first strain-gauge element, the second signal from the second strain-gauge element, and the third signal.

10. The apparatus of claim 9 , wherein:
the measure of stretch deformation is indicative of an average change in lengths in relationship to an undeformed length of the first and second strain gauge elements; and
the measure of flex deformation is indicative of a bend radius of an angular bend of portions of the substrate on which the first and second strain-gauge elements are formed.

11. The apparatus of claim 9 , wherein the deformation analyzer is further configured to determine whether the stretch deformation corresponds to a compression stretch or an elongation stretch, by comparing the measured first, second, and third signals, based on a sign of changes in resistances of the first and second strain gauge elements and a sign of change in capacitance of the substrate.

12. A system comprising:
one or more deformation sensors, each deformation sensor including:
a first strain-gauge element coupled to a substrate and configured to output a first signal indicative of a resistance of the first strain-gauge element, wherein the first signal is measurable across a first terminal and a second terminal of the first strain-gauge element; and
a second strain-gauge element coupled to the substrate and configured to output a second signal indicative of a resistance of the second strain-gauge element,
wherein the deformation sensor is configured to output a third signal indicative of a capacitance measurable between a terminal of the first strain-gauge element and a terminal of the second strain-gauge element.

13. The system of claim 12 , further comprising:
a measurement circuit configured to measure the first signal from the first strain-gauge element and the second signal from the second strain-gauge element in response to an applied deformation.

14. The system of claim 13 , further comprising:
a deformation analyzer configured to compute a measure of stretch deformation and a measure of flex deformation of the system, based on the measured first signal from the first strain-gauge element, the measured second signal of the second strain-gauge element, and the third signal.

15. The system of claim 12 , wherein:
each of the first and second strain-gauge elements of the deformation sensor has a horse-shoe shape comprising an arcuate head and a pair of elongate leads extending from ends of the arcuate head; and
the shapes are configured to circumscribe an articulating joint, a movement of the articulating joint resulting in a corresponding deformation of the deformation sensor.

16. The system of claim 12 , wherein the one or more deformation sensors are included in a wearable device.

17. The system of claim 12 , wherein the one or more deformation sensors are included in a finger of a glove.

18. The system of claim 12 , wherein the one or more deformation sensors comprise a plurality of deformation sensors, each included in a different finger of a glove.

19. A method comprising:
measuring a first signal indicative of a resistance of a first strain-gauge element coupled to a substrate, wherein the first signal is measured across a first terminal and a second terminal of the first strain-gauge element;
measuring a second signal indicative of a resistance of a second strain-gauge element coupled to the substrate; and
measuring a third signal indicative of a capacitance measurable between a terminal of the first strain-gauge element and a terminal of the second strain-gauge element.

20. The method of claim 19 , further comprising:
computing a measure of stretch deformation and a measure of flex deformation based on the measured first signal from the first strain-gauge element, the measured second signal of the second strain-gauge element, and the measured third signal.

Assignees

• Facebook Tech Llc

Inventors

• Keller Sean Jason
• Trutna Tristan Thomas
• Perek David R
• Cleary Iii Bruce A

Classifications

• G01D21/02

  Measuring two or more variables by means not covered by a single other subclass · CPC title

• G01B7/18

  using change in resistance · CPC title

• G01L1/22

  using resistance strain gauges · CPC title

• G01L1/14

  by measuring variations in capacitance or inductance of electrical elements, e.g. by measuring variations of frequency of electrical oscillators · CPC title

• G01L5/165

  using variations in capacitance · CPC title