Method for Querying a Piezoelectric Resonator and Querying Device Implementing Said Querying Method

• US 20100332157A1
• Filed: 02/19/2009
• Published: 12/30/2010
• Est. Priority Date: 02/22/2008
• Status: Active Grant

• Current Assignee: SENSeOR
• Original Assignee: SENSeOR
• Inventors: Friedt, Jean-Michel
• Granted Patent: US 8,392,128 B2
• Time in Patent Office: Days
• US Class Current: 702/54
• CPC Class Codes: B60C 23/0449 Passive transducers, e.g. using surface acoustic waves, backscatter technology or pressure sensitive resonators near field passive transducers B60C23/0428
• CPC Class Codes: G01L 1/165 with acoustic surface waves
• CPC Class Codes: G01L 19/086 for remote indication
• CPC Class Codes: G01L 9/0025 with acoustic surface waves

Abstract

A method for interrogating a passive sensor comprising at least one piezoelectric resonator includes the following steps:

• • the identification of the characteristic width of the resonant frequency band of the resonator;
  • the determination of a scan interval equal to a third of the measured bandwidth;
  • a first series of three interrogation measurements with signals respectively at a first frequency, at a second frequency and at a third frequency making it possible to define a first resonance value, a second resonance value and a third resonance value;
  • the determination by a parabolic fitting operation of the resonator response curve on the basis of said first, second and third resonance values, so as to calculate a first value of the frequency in real time of the resonator.

The invention also relates to an electronic device for interrogating a passive sensor comprising at least one piezoelectric resonator and comprising a micro-controller implementing the interrogation method of the invention.

Claims

1. A method for interrogating a passive sensor comprising at least one piezoelectric resonator comprising the following steps:

the identification of the characteristic width of the resonant frequency band of the resonator Δ

f_0S;

the determination of a scan interval equal to a third of the measured bandwidth Δ

f=Δ

f_0S/3;

a first series of three interrogation measurements with signals respectively at a first frequency (f₁), at a second frequency (f₂) and at a third frequency (f₃) making it possible to define a first resonance value (Y₁), a second resonance value (Y₂) and a third resonance value (Y₃);

the determination by a parabolic fitting operation of the resonator response curve on the basis of said first, second and third resonance values, so as to calculate a first value of the frequency in real time (f₀₁) of the resonator.

2. The method for interrogating a passive sensor as claimed in claim 1, wherein the scan interval is constant and that the value of the frequency of the resonator is defined by the following equation:

f₀=f₂+Δ

f/2·

(Y₁−

Y₃)/(Y₁+Y₃−

2Y₂)

3. The method for interrogating a passive sensor as claimed in claim 1, wherein the first series of interrogation measurements is performed at three frequencies such that the first, second and third resonance values define an isosceles triangle.

4. The method for interrogating a passive sensor as claimed in claim 1, wherein it furthermore comprises a second iterative step of interrogation measurements at a fourth frequency (f₄), a fifth frequency (f₅) and sixth frequency (f₆) defined respectively by the following equations:

f₄=f₀₁−

Δ

f

f₅=f₀₁

f₆=f₀₁+Δ

f

so as to refine a second frequency value in real time (f₀₂).

5. An electronic device for interrogating a passive sensor comprising at least one piezoelectric resonator, said device comprising at least one first assembly for generating radiofrequency signals, a second electronic assembly for processing radiofrequency signals and at least one passive sensor wherein the second assembly for processing radiofrequency signals comprises a micro-controller implementing the method of interrogation as claimed in claim 1.

6. The electronic device for interrogating a passive sensor as claimed in claim 5, wherein it furthermore comprises an analog/digital converter.

7. The use of an electronic device as claimed in claim 5, for the interrogation of a passive sensor integrated into a system placed in rotation.

8. The electronic interrogation device as claimed in claim 5, wherein the passive sensor is integrated into a wheel and further comprising at least one resonator, further comprising means for determining the temperature of the wheel on the basis of the measurement of the resonant frequency in real time of said resonator.

9. The electronic interrogation device as claimed in claim 5, wherein the passive sensor is integrated into a wheel and further comprising at least one resonator, further comprising means for determining the pressure of the wheel on the basis of the measurement of the resonant frequency in real time of said resonator.