TRANSDUCER ARRAY SELF-DIAGNOSTICS AND SELF-HEALING

• US 20080255781A1
• Filed: 02/28/2008
• Published: 10/16/2008
• Est. Priority Date: 04/16/2007
• Status: Active Grant

• Current Assignee: Acellent Technologies, Inc.
• Original Assignee: Acellent Technologies, Inc.
• Inventors: Qing, Xinlin, Beard, Shawn J., Zhang, Chang
• Granted Patent: US 9,109,999 B2
• Time in Patent Office: Days
• US Class Current: 702/59
• CPC Class Codes: G01N 2291/0427 Flexural waves, plate waves, e.g. Lamb waves, tuning fork, cantilever
• CPC Class Codes: G01N 2291/106 one or more transducer arrays
• CPC Class Codes: G01N 29/041 on the surface of the material, e.g. using Lamb, Rayleigh or shear waves
• CPC Class Codes: G01N 29/36 Detecting the response signal , e.g. electronic circuits specially adapted therefor
• CPC Class Codes: G01N 29/4463 Signal correction, e.g. distance amplitude correction [DAC], distance gain size [DGS], noise filtering

Abstract

A method of performing transducer self-diagnostics and self-healing on an array of sensor transducers bonded to a structure for health monitoring includes measuring impedance to detect whether a transducer is missing, or a connection is damaged. Pitch-catch signals generated between one or more pairs of transducers are analyzed for detecting defects according to selected criteria of defect size and location to determine whether the sensors are damaged or partially/fully disbanded. Based on the resulting map of operational transducers, signal transmission paths are added/extended between additional pairs of transducers to maintain inspection coverage of the structure according to the selected criteria.

Claims

1. A method of performing self-diagnostics on an array of transducers, comprising:

measuring an impedance of a selected one of the transducers to detect whether the selected one of the transducers is missing, or an electrical connection to the selected one of the transducers is damaged;

generating pitch-catch signals between one or more pairs of the transducers;

analyzing the obtained pitch-catch signals according to selected criteria to determine whether one or more transducers of the pairs of the transducers are damaged or partially or fully disbanded.

2. The method of claim 1, the measuring further comprising:

applying a waveform voltage to the selected one of the transducers to measure the impedance;

comparing the impedance to a reference value of impedance corresponding to a satisfactory transducer; and

determining if the measured impedance indicates an open, short or normal circuit connection to the transducer.

3. The method of claim 2, wherein the comparing is a measurement of the ratio of a voltage signal measured across the selected one of the transducers in series with a reference resistor to a voltage signal generated by a waveform generator.

4. The method of claim 1, wherein the generating further comprises:

transmitting a signal from a first sensor transducer to a second and a third sensor transducer, wherein the first, second and third transducers are arranged in an inline sequential configuration; and

detecting the signal at the second and third transducers.

5. The method of claim 1, wherein the analyzing further comprises:

comparing the detected pitch-catch signals to selected criteria, the selected criteria being baseline data of signals transmitted from a first baseline transducer to a second and third baseline transducer, wherein the baseline data is obtained when baseline transducers are arranged in an inline sequential configuration and are known to be properly functioning and properly bonded to a baseline structure; and

determining from the compared signals if any of the transducers of the one or more pairs of the transducers is bonded, or completely or partially disbanded.

6. The method of claim 5, wherein the determining further comprises identifying a completely or partially disbanded transducer from the one or more pairs of transducers.

7. A method of transducer array fault diagnostics, comprising:

defining location coordinates for one or more of the transducers of the array;

assigning an identifier to each transducer;

associating a corresponding electrical connection channel identifier with each transducer;

assembling a data input file, wherein the file comprises the transducer identifier and the channel identifier;

executing an impedance diagnostic measurement process, wherein an impedance measurement is made in association with the one or more transducers;

assigning a fault code to the one or more transducers on the basis of the impedance diagnostic measurement process; and

creating an impedance diagnostic output file, wherein the output file comprises the fault code assigned to the one or more transducers.

8. The method of claim 7, wherein the data input file further comprises the coordinate locations of the one or more transducers.

9. The method of claim 7, wherein the data output file comprises the data input file data and the fault code associated with the one or more transducers.

10. The method of claim 7, wherein the reporting comprises a graphical display representative of the coordinate locations of the one or more transducers and a graphical indicator that distinguishes faulty ones of the one or more transducers from properly functioning ones of the one or more transducers.

11. The method of claim 10, wherein the graphical indicator is a color code associated with the fault code.

12. The method of claim 7, wherein the reporting comprises a list of one or more transducers having an assigned fault code and associated fault descriptions, wherein the fault descriptions are based on the assigned fault codes.

13. A method for self-healing of an array of transducers, comprising:

identifying one or more faulty transducers in an array comprising a plurality of transducers;

determining the remaining operational transducers;

generating a net of possible usable signal paths between the operational transducers based on the identifying and a coordinate location of each of the operational transducers;

removing paths from the net associated with the faulty transducers;

analyzing whether the remaining paths of the net are sufficient to provide coverage of a region encompassed by the array, wherein coverage is determined according to a selected criteria;

performing pitch-catch signal transmission between pairs of operational transducers to determine if one or more operational transducers are disbanded;

adding signal transmission paths between pairs of the operational transducers to provide coverage not provided if one or more of the transducers are disbanded; and

repeating the analyzing, performing, and adding until coverage is provided according to the selected criteria.

14. The method of claim 13, wherein determining the coverage according to selected criteria comprises:

selecting a defect location within the region encompassed by the array;

defining a defect size by a diameter of a circle centered on the defect location; and

determining if the defect defined by the location and the diameter intersects at least one remaining or added path between one or more pairs of the transducers of the array.

15. A system for transducer array self-diagnostics, comprising:

an array of one or more transducers;

an impedance measurement system coupled to the array and adapted to measure electrical characteristics of the one or more transducers;

a signal transmission and detection system coupled to the array and adapted for generating transmission signals along paths between pairs of the transducers;

one or more programs stored on a computer readable medium executable on at least one computer and adapted to control the impedance measurement system and the signal transmission and detection system, and to determine paths between the pairs of the transducers according to output from the impedance measurement system and the signal transmission and detection system.

16. The system of claim 15, wherein the impedance measurement system comprises:

a first multiplexer having a plurality of first multiple output ports and a first single input port adapted to couple to one or more transducers of the array through the plurality of first multiple output ports;

a reference resistor coupled at a first end to the first multiplexer first single input port;

a wave signal generator coupled to a second end of the reference resistor;

a second multiplexer having one or more second multiple output ports and a second single input port, one of the second multiple output ports configured to couple to the second end of the reference resistor;

an analog to digital signal converter comprising a first and a second analog input channel and a digital output channel, the first analog channel configured to couple to the first end of the reference resistor and the waveform generator, the second analog channel configured to couple to the second multiplexer single input port;

a process controlling computer adapted to control the waveform signal generator, first and second multiplexer and analog to digital converter.

17. A system for sensor self-diagnostics, comprising:

an array of one or more transducers;

impedance measurement means for measuring electrical impedance characteristics of the one or more transducers;

signal transmission and detection means for generating transmission signals along paths between pairs of the transducers;

means to control the impedance measurement means and the signal transmission and detection means so as to determine paths connecting selected transducers according to the measured electrical impedance characteristics and the transmitted signals.