Detection of an abnormal signal in a compound sampled signal

• US 9,772,368 B2
• Filed: 12/04/2012
• Issued: 09/26/2017
• Est. Priority Date: 05/11/2007
• Status: Active Grant

• Current Assignee: Bosch Automotive Service Solutions LLC (SPX Corporation)
• Original Assignee: Bosch Automotive Service Solutions LLC (SPX Corporation)
• Inventors: Kidd, Moray, Shi, Zhanqun
• Primary Examiner(s): Vargas, Manuel Rivera
• Application Number:
  US13/693,849
• Publication Number:
  US 20130096855A1
• Time in Patent Office: 1,757 Days
• CPC Class Codes: G01H 3/08 Analysing frequencies present in complex vibrations, e.g. comparing harmonics present acoustic presence detection G01V1/001
• CPC Class Codes: G01R 31/08 Locating faults in cables, transmission lines, or networks
• CPC Class Codes: G06F 15/00 Digital computers in general details G06F1/00 – G06F13/00; Data processing equipment in general

Abstract

A technique detects an abnormal signal in a compound sampled signal recorded in the time domain. The technique involves dividing the sampled signal recorded in the time domain into sample segments; transforming each of the sample segments from the time domain into the frequency domain to determine transformed segments, each transformed segment having frequency points, each frequency point having an amplitude associated with a certain frequency; for a frequency point in a given transformed segment, determining a ratio by dividing the amplitude of the frequency point by a value indicative of an average of the amplitudes of the frequency points at the same frequency across transformed segments; repeating the determination of a ratio for frequency points in each transformed segment to determine ratios for each transformed segment; repeating the determination of ratios for transformed segments; and using the ratios to detect the abnormal signal in the compound sampled signal.

Claims

1. A computer-implemented method of detecting an origin of a fault signal caused by a fault in a vehicle, comprising:

receiving, via a recorder, a compound sampled signal recorded in a time domain, wherein the compound signal includes the fault signal;

identifying, via a computer processor, the fault signal in the compound sampled signal, wherein the fault signal is identified based at least in part on a deviation ratio of an amplitude of a frequency point of the compound sampled signal in a frequency domain with a mean value of amplitude of all frequency points of the compound sampled signal in the frequency domain, wherein the frequency domain corresponds to a segment in the time domain;

playing the corresponding segment of the time domain that corresponds to a segment of the frequency domain having the identified fault signal to a user or a driver who confirms the identified fault signal is attributable to the fault in the vehicle;

extracting the confirmed identified fault signal from the compound sampled signal with the processor by removing frequency points with little or no deviation from the mean value;

comparing, via the computer processor, the confirmed fault signal with a library of predetermined fault signals; and

determining, via the computer processor, an origin of the fault signal.

2. The computer-implemented method of claim 1, wherein identifying the fault signal in the compound sampled signal comprises:

dividing the compound sampled signal recorded in the time domain into a plurality of sample segments; and

transforming each of the plurality of sample segments from the time domain into the frequency domain to determine a plurality of transformed sample segments, wherein each of the plurality of transformed sample segments include a plurality of frequency points.

3. The computer-implemented method of claim 2, wherein the amplitude of each of the plurality of frequency points of the plurality of transformed sample segments is associated with a certain frequency.

4. The computer-implemented method of claim 3, wherein the deviation ratio is determined by dividing the amplitude of the frequency point by the mean value of the amplitudes of the plurality of frequency points at same frequency across the plurality of transformed sample segments.

5. The computer-implemented method of claim 4, wherein a determination of the deviation ratio is repeated for the plurality of frequency points in each of the plurality of transformed sample segments to determine a plurality of deviation ratios for each of the plurality of frequency points and repeating the determination of the deviation ratio for the plurality of frequency points for the plurality of transformed sample segments.

6. The computer-implemented method of claim 5, wherein the mean value of the amplitudes of the plurality of frequency points at the same frequency across the plurality of transformed sample segments is determined across a majority of the plurality of transformed sample segments.

7. The computer-implemented method of claim 5, wherein the mean value of the amplitudes of the plurality of frequency points at the same frequency across the plurality of transformed sample segments is determined across all of the plurality of transformed sample segments.

8. The computer-implemented method of claim 5, wherein the mean value of the amplitudes of the plurality of frequency points at the same frequency across the plurality of transformed sample segments is indicative of a mode value.

9. The computer-implemented method of claim 5, further comprising adding the plurality of deviation ratios together to determine a summed ratio for each of the plurality of transformed sample segments.

10. The computer-implemented method of claim 9, wherein each deviation ratio of the plurality of deviation ratios is squared before each deviation ratio is added together to determine a summed squared ratio for each of the plurality of transformed sample segments.

11. The computer-implemented method of claim 10, further comprising identifying sample segments having highest summed ratios or summed squared ratios.

12. The computer-implemented method of claim 11, wherein the highest summed ratios or the summed squared ratios are deemed to be highest if they exceed a predetermined threshold.

13. The computer-implemented method of claim 12, wherein the predetermined threshold is a percentage of a peak summed ratio or summed squared ratio.

14. The computer-implemented method of claim 11, further comprising taking away from the plurality of frequency points of a transformed sample segment deemed to have a highest summed ratio or summed squared ratio the plurality of frequency points of a transformed sample segment deemed not to have the highest summed ratio or summed squared ratio.

15. The computer-implemented method of claim 11, wherein a transformed sample segment or segments having the highest summed ratios or summed squared ratios are transformed from the frequency domain into the time domain.

16. The computer-implemented method of claim 11, wherein a location of the plurality of transformed sample segments in the frequency domain having the highest summed ratios or summed squared ratios is used to identify corresponding sample segments in the time domain.

17. The computer-implemented method of claim 11, wherein the plurality of sample segments in the time domain is analyzed to determine if the plurality of sample segments in the time domain contain some or all of the fault signal.

18. The computer-implemented method of claim 17, wherein the analysis comprises using detection hardware or software to compare the plurality of sample segments in the time domain with a plurality of stored signals.

19. A non-transitory computer readable medium storing computer readable instructions configured to cause a computer to:

receive a compound sampled signal recorded in a time domain, wherein the compound sampled signal includes a fault signal caused by a fault in a vehicle;

identify the fault signal in the compound sampled signal, wherein the fault signal is identified based at least in part on a deviation ratio of an amplitude of a frequency point of the compound sampled signal in frequency domain with a mean value of amplitude of all frequency points of the compound sampled signal in the frequency domain;

play the corresponding segment of the time domain that corresponds to a segment of the frequency domain having the identified fault signal to a user or a driver who confirms the identified fault signal is attributable to the fault in the vehicle;

extract the confirmed identified fault signal from the compound sampled signal by removing frequency points with little or no deviation from the mean value;

compare the confirmed identified fault signal with a library of predetermined faults signals; and

determine an origin of the fault signal.

20. A computer apparatus for detecting an origin of a fault signal, comprising:

a memory storing processor readable instructions; and

a processor that reads and executes the processor readable instructions stored in the memory;

wherein the processor readable instructions include instructions configured to cause the processor to;

receive a compound sampled signal recorded in a time domain, wherein the compound sampled signal includes the fault signal caused by a fault in a vehicle;

identify the fault signal in the compound sampled signal, wherein the fault signal is identified based at least in part on a deviation ratio of an amplitude of a frequency point of the compound sampled signal in a frequency domain with a mean value of amplitude of all frequency points of the compound sampled signal in the frequency domain;

play the corresponding segment of the time domain that corresponds to a segment of the frequency domain having the identified fault signal to a user or a driver who confirms the identified fault signal is attributable to the fault in the vehicle;

extract the confirmed identified fault signal from the compound sampled signal by removing frequency points with little or no deviation from the mean value;

compare the confirmed identified fault signal with a library of predetermined faults signals; and

determine an origin of the fault signal.