Microelectromechanical mechanisms for real-time mechanical vibration signature monitoring and analysis

• US 6,412,131 B1
• Filed: 02/22/2000
• Issued: 07/02/2002
• Est. Priority Date: 02/22/2000
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Zhao, Feng, Berlin, Andrew A., Hung, Elmer S.
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): MILLER, ROSE MARY
• Application Number:
  US09/510,366
• Time in Patent Office: 861 Days
• Field of Search: 736/59, 736/60, 736/61, 735/93, 702/56
• US Class Current: 73/659
• CPC Class Codes: G01H 1/003 of rotating machines G01H1/10 takes precedence
• CPC Class Codes: G01H 11/08 using piezoelectric devices
• CPC Class Codes: G01L 1/10 by measuring variations of frequency of stressed vibrating elements, e.g. of stressed strings using resistance strain gauges G01L1/22
• CPC Class Codes: G01L 9/0019 of a semiconductive element
• CPC Class Codes: G01M 7/025 Measuring arrangements
• CPC Class Codes: G01N 2291/014 Resonance or resonant frequency
• CPC Class Codes: G01N 2291/106 one or more transducer arrays
• CPC Class Codes: G01N 29/14 using acoustic emission techniques echo of particles G01N29/046; measuring mechanical vibrations or acoustic waves in solids in general G01H1/00
• CPC Class Codes: G01N 29/38 by time filtering, e.g. using time gates
• CPC Class Codes: G01N 29/4427 with stored values, e.g. threshold values
• CPC Class Codes: G01N 29/46 by spectral analysis, e.g. Fourier analysis or wavelet analysis spectral signal processing per se G06F17/14

Abstract

A MEMS-based system that enables low cost, low power, single chip realization of real-time signal detection and fault diagnosis. The system is suitable for analyzing the time-varying properties of a signal that are important for condition-based monitoring of electro-mechanical machines or structures. The system includes mechanical sensors that sense input signals such as vibration, signal templates of fault conditions, logic units that detect, store, and compare signal features to provide a diagnostic state, and an output readout mechanism to couple the diagnostic state to readout device that provides an external signal.

Claims

1. A micro-electro-mechanical system for signature analysis comprising:

an array of sensors that measure a time varying event, wherein the array outputs a time-windowed sensor signal in response to operation of a system of interest;

a plurality of signal templates representing normal and faulty operating conditions of the system of interest;

at least one logic unit that compares the sensor signal with the signal templates, and provides a diagnostic state based on the comparison; and

a readout device that outputs the diagnostic state as an external signal.

2. The micro-electro-mechanical system of claim 1, wherein the sensor signal is mechanically stored.

3. The micro-electro-mechanical system of claim 1, wherein the comparison is performed by at least one bit comparator that compares the sensor signal to a stored bit pattern representing the signal template.

4. The micro-electro-mechanical system of claim 1, wherein the readout device outputs the diagnostic signal in human-readable form.

5. The micro-electro-mechanical system of claim 1, wherein each sensor of the array has a programable temporal configuration.

6. The micro-electro-mechanical system of claim 5, where each sensor of the array includes clamps to modify the temporal configuration of the sensor.

7. The micro-electro-mechanical system of claim 5, wherein the clamps reset the sensors and the sensors output a subsequent time-windowed sensor signal in response to operation of the system of interest.

8. The micro-electro-mechanical system of claim 1, wherein the sensor array comprises a plurality of sensors each having a different resonant frequency and temporal configuration to detect and read-out time varying frequency information from the system of interest.

9. The micro-electro-mechanical system of claim 2, wherein the signal templates are stored in mechanical memories and compared to the sensor signal using a mechanical logic implementation.

10. The micro-electro-mechanical system of claim 1, further including a plurality of arrays, wherein each array measures the frequency content of a different time window of the operation of the system of interest.

11. The micro-electro-mechanical system of claim 1, wherein the micro-electro-mechanical system is on a single semiconductor chip.

12. A portable signature analysis system comprising:

an array of MEMS sensors that detect a time varying event, wherein the array outputs a time-windowed sensor signal in response to operation of a system of interest;

a plurality of stored signal templates representing normal and faulty operating conditions of the system of interest;

at least one logic unit that compares the sensor signal with the stored signal templates, and provides a diagnostic state based on the comparison; and

a readout component that outputs the diagnostic state in a human readable form.