Self-powered sensing system for the monitoring of quasi-static structural response

Patent metadata

Field	Value
Publication number	US-9793830-B2
Application number	US-201415022046-A
Country	US
Kind code	B2
Filing date	Sep 16, 2014
Priority date	Sep 16, 2013
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

A self-powered sensing system is provided for the monitoring of quasi-static structural responses. The sensing system is comprised of: an energy concentrator having a member configured to detect a variation of a physical stimuli and change shape in response to the variation of the physical stimuli, where the variation typically occurs at a frequency less than one Hertz; a transducer coupled the member of the energy concentrator and generates a voltage in response to the change in shape of the member; and an event logging circuit configured to receive the voltage from the transducer and log the voltage in a non-volatile memory. Physical stimuli may include temperature, pressure or an applied force.

First claim

What is claimed is:

1. A self-powered sensing system, comprising:
an energy concentrator having a member configured to detect a variation of a physical stimuli and change shape in response to the variation of the physical stimuli, where the variation occurs at a frequency less than one Hertz;
a transducer coupled to the member of the energy concentrator and generates a voltage in response to the change in shape of the member; and
an event logging circuit configured to receive the voltage from the transducer and operates to log the voltage in a non-volatile memory
wherein the member of the energy concentrator is defined as a strip having two opposing planar surfaces substantially wider than remaining surfaces, where the strip is constrained by a first wall disposed adjacent to one planar surface of the strip and a second wall disposed adjacent to other planar surface of the strip.

2. The self-powered sensing system of claim 1 wherein the member of the energy concentrator changes shape in response to a force applied thereto.

3. The self-powered sensing system of claim 1 wherein the member of the energy concentrator is interfaced with a structure to be monitored.

4. The self-powered sensing system of claim 1 wherein the transducer is defined as a cantilever having one end coupled to the strip, the cantilever extending outwardly from the strip and includes piezoelectric material disposed on a surface thereof.

5. The self-powered sensing system of claim 1 wherein the non-volatile memory is comprised of at least one floating gate transistor.

6. The self-powered sensing system of claim 5 wherein the event logging circuit includes a current reference circuit having a floating gate transistor operating in a weak-inversion mode, the current reference circuit configured to receive the voltage signal from the transducer and, in response thereto, output an injection current into the non-volatile memory.

7. The self-powered sensing system of claim 6 wherein the event logging circuit includes an operational amplifier interfaced with the floating gate transistor of the non-volatile memory to ensure that the source-to-drain voltage of the floating gate transistor is held constant.

8. The self-powered sensing system of claim 1 wherein the member of the energy concentrator changes shape in response to variation in one of temperature or pressure.

9. A self-powered sensing system, comprising:
an energy concentrator having a member configured to accumulate potential energy in response to variations of a physical stimuli applied thereto and to release the accumulated potential energy by changing shape when the accumulated potential energy exceeds a threshold, where the variation of the physical stimuli occurs at a frequency less than one Hertz;
a transducer coupled to the member of the energy concentrator and, in response to the change in shape of the member, generates a voltage; and
an event logging circuit configured to receive the voltage from the transducer and operates to log the voltage in a non-volatile memory.

10. The self-powered sensing system of claim 9 wherein the member of the energy concentrator is defined as a hollow cylinder configured to exhibits a snap-through event in response to a force applied axially thereto, where magnitude of the force changes at a frequency less than one Hertz and the snap-through event is constrained laterally by curvature of the cylinder.

11. The self-powered sensing system of claim 9 wherein the member of the energy concentrator changes shape in response to a force applied thereto.

12. The self-powered sensing system of claim 9 wherein the member of the energy concentrator is interfaced with a structure to be monitored.

13. The self-powered sensing system of claim 9 wherein the member of the energy concentrator is defined as a strip having two opposing planar surfaces substantially wider than remaining surfaces, where the strip is constrained by a first wall disposed adjacent to one planar surface of the strip and a second wall disposed adjacent to other planar surface of the strip.

14. The self-powered sensing system of claim 13 wherein the transducer is defined as a cantilever having one end coupled to the strip, the cantilever extending outwardly from the strip and includes piezoelectric material disposed on a surface thereof.

15. The self-powered sensing system of claim 9 wherein the non-volatile memory is comprised of at least one floating gate transistor.

16. The self-powered sensing system of claim 15 wherein the event logging circuit includes a current reference circuit having a floating gate transistor operating in a weak-inversion mode, the current reference circuit configured to receive the voltage signal from the transducer and, in response thereto, output an injection current into the non-volatile memory.

17. The self-powered sensing system of claim 16 wherein the event logging circuit includes an operational amplifier interfaced with the floating gate transistor of the non-volatile memory to ensure that the source-to-drain voltage of the floating gate transistor is held constant.

18. The self-powered sensing system of claim 9 wherein the member of the energy concentrator changes shape in response to variation in one of temperature or pressure.

Assignees

• Univ Michigan State

Inventors

• Lajnef Nizar
• Chakrabartty Shantanu
• Burgueno Rigoberto
• Wassim Borchani

Classifications

• G01D9/00

  Recording measured values · CPC title

• H02N2/181 Primary

  Circuits; Control arrangements or methods · CPC title

• G01L9/08

  by making use of piezoelectric devices {, i.e. electric circuits therefor} · CPC title

• G01K5/00

  Measuring temperature based on the expansion or contraction of a material (G01K9/00 takes precedence; giving other than momentary value of temperature G01K3/00) · CPC title

• H02N2/18

  producing electrical output from mechanical input, e.g. generators (for measurement devices G01) · CPC title