Self-Powered Sensing System For The Monitoring Of Quasi-Static Structural Response

Patent metadata

Field	Value
Publication number	US-2016233797-A1
Application number	US-201415022046-A
Country	US
Kind code	A1
Filing date	Sep 16, 2014
Priority date	Sep 16, 2013
Publication date	Aug 11, 2016
Grant date	—

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

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.

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 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.

5 . The self-powered sensing system of claim 4 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.

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

7 . The self-powered sensing system of claim 6 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.

8 . The self-powered sensing system of claim 7 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.

9 . 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.

10 . A self-powered sensing system, comprising
an energy concentrator having a buckling member that exhibits a snap-through event in response to a force applied thereto, where magnitude of the force changes at a frequency less than one Hertz; a transducer coupled to the buckling member and, in response to the occurrence of a snap-through event of the buckling member, generate a voltage; and an event logger circuit configured to receive the voltage from the transducer and operates to log the voltage in a non-volatile memory.

11 . The self-powered sensing system of claim 10 wherein the buckling member is further defined as a strip having two opposing planar surface 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.

12 . The self-powered sensing system of claim 11 wherein the buckling member is configured to exhibit snap-through events between three or more stable positions.

13 . The self-powered sensing system of claim 12 wherein the transducer is further defined as a cantilever having one end coupled to the buckling member, the cantilever extending outwardly from the buckling member and includes a piezoelectric material disposed on a surface thereof.

14 . The self-powered sensing system of claim 13 wherein the non-volatile memory is comprised of at least one floating gate transistor.

15 . The self-powered sensing system of claim 14 wherein the event logger includes a 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.

16 . The self-powered sensing system of claim 15 wherein the event logger includes a full-bridge rectifier interposed between the transducer and the current reference circuit.

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 .- 24 . (canceled)

25 . A method for monitoring a quasi-status response using a self-powered sensor, comprising:
arranging a buckling member in a structured to be monitored, where the buckling member exhibits a snap-through event in response to a force applied thereto and magnitude of the force changes at a frequency less than one Hertz; attaching a transducer to the buckling member, where the transducer is configured to actuate in response to the occurrence of a snap-through event of the buckling member; receiving, by a drive circuit, a voltage signal from the transducer, wherein the voltage signal is caused by the occurrence of a snap-through event of the buckling member; and logging, by the drive circuit, a metric in a non-volatile memory, where the metric pertains to the force applied to the buckling member and the non-volatile memory is powered by the voltage signal from the transducer.

26 . The method of claim 25 wherein the buckling member includes a longitudinal axis and is constrained laterally in relation to the longitudinal axis.

27 .- 31 . (canceled)

32 . The self-powered sensing system of claim 1 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.

Assignees

• Univ Michigan State

Inventors

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

Classifications

• G01D9/00

  Recording measured values · 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

• G01L9/08

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

• H01L41/1136

  Electricity · mapped topic

• H02N2/181 Primary

  Circuits; Control arrangements or methods · CPC title