Diagnostic method, system and device for a rotorcraft drive system

Patent metadata

Field	Value
Publication number	US-10464689-B2
Application number	US-201715677885-A
Country	US
Kind code	B2
Filing date	Aug 15, 2017
Priority date	Aug 17, 2016
Publication date	Nov 5, 2019
Grant date	Nov 5, 2019

Abstract

A method, system, and device for diagnosing an anomaly of a monitored component in a drive train, the method including: obtaining original data based on samples of a tachometer signal; processing the original data to obtain rotational information; processing the original data to produce a sine spectrum; determining complex magnitudes of the sine spectrum; removing dominate torsional mode residuals from the complex magnitudes of the sine spectrum to produce a frequency spectrum; and determining a condition indicator from the frequency spectrum.

First claim

What is claimed is:

1. A method of diagnosing an anomaly of a monitored component in a drive train, the method comprising:
obtaining, by a device configured to diagnose an anomaly, original data based only on samples of a tachometer signal;
processing, by the device configured to diagnose the anomaly, the original data to obtain rotational information;
processing, by the device configured to diagnose the anomaly, the original data to produce a sine spectrum;
determining, by the device configured to diagnose the anomaly, complex magnitudes of the sine spectrum;
removing, by the device configured to diagnose the anomaly, dominate torsional mode residuals from the complex magnitudes of the sine spectrum to produce a frequency spectrum; and
determining, by the device configured to diagnose the anomaly, a condition indicator from the frequency spectrum;
wherein the step of determining the condition indicator from the frequency spectrum comprises:
(a) determining a threshold and a noise floor for the frequency spectrum;
(b) detecting peaks of the frequency spectrum over the threshold, each peak having a frequency and a magnitude;
(c) calculating the difference in the frequency between the peaks; and
(d) summing the magnitudes of all peaks with a difference in the frequency equal to a rotational frequency of the component to determine the condition indicator.

2. The method according to claim 1 , wherein the step of processing to produce the sine spectrum comprises performing a discrete Fourier transform (DFT).

3. The method according to claim 1 , wherein the step of removing dominate torsional mode residuals comprises:
monitoring torsional vibrations in a gearbox in a drivetrain of a rotorcraft; and
identifying the dominate torsional mode residuals of the gearbox.

4. The method according to claim 1 , further comprising:
determining a plurality of condition indicators.

5. The method according to claim 4 , further comprising:
based upon the plurality of condition indicators, determining an unhealthy condition of the plurality of condition indicators.

6. The method according to claim 5 , further comprising:
identifying an unhealthy component.

7. The method according to claim 6 , further comprising:
adjusting at least one of an operation and a maintenance of the unhealthy component.

8. The method according to claim 1 , wherein the device configured to diagnose the anomaly further comprises:
a display;
wherein the device provides a real-time indication of the anomaly in the monitored component.

9. The method according to claim 1 , further comprising:
storing a history, by the device configured to diagnose the anomaly, of original data;
wherein the history being stored before a diagnostic operation for the component is performed.

10. A device configured to diagnose an anomaly of a monitored component in a drive train, the device comprising:
a memory configured to store original data of a tachometer signal;
one or more processors in communication with the memory, the one or more processors being configured to:
obtain a original data based only on samples of the tachometer signal;
process the original data to obtain rotational information;
process the original data to produce a sine spectrum;
determine complex magnitudes of the sine spectrum;
remove dominate torsional mode residuals from the complex magnitudes of the sine spectrum to produce a frequency spectrum; and
determine a condition indicator from the frequency spectrum;

wherein the determine the condition indicator from the frequency spectrum comprises:
(a) determine a threshold and a noise floor for the frequency spectrum;
(b) detect peaks of the frequency spectrum over the threshold, each peak having a frequency and a magnitude;
(c) calculate the difference in the frequency between the peaks; and
(d) sum the magnitudes of all peaks with a difference in the frequency equal to a rotational frequency of the component to determine the condition indicator.

11. The device according to claim 10 , wherein the processors are configured to:
determine a plurality of condition indicators.

12. The device according to claim 11 , wherein the processors are configured to:
based upon the plurality of condition indicators, determine an unhealthy condition of the plurality of condition indicators; and
identify an unhealthy component.

13. The device according to claim 12 , wherein the processors are configured to:
adjust at least one of an operation and a maintenance of the unhealthy component.

14. The device according to claim 10 , wherein the device further comprises:
a display;
wherein the device provides a real-time indication of the anomaly in the monitored component.

15. The device according to claim 10 , wherein the original data is stored before a diagnostic operation for the component is performed.

16. A system for diagnosing an anomaly of a monitored component in a drive train, the system comprising:
a rotorcraft comprising a body, a power train coupled to the body and comprising a power source and a drive train coupled to the power source;
a tachometer coupled to the drive train; and
a diagnostic device associated with the tachometer, the diagnostic device operable to:
obtain original data based only on samples of a tachometer signal;
process the original data to obtain rotational information;
process the original data to produce a sine spectrum;
determine complex magnitudes of the sine spectrum;
remove dominate torsional mode residuals from the complex magnitudes of the sine spectrum to produce a frequency spectrum; and
determine a condition indicator from the frequency spectrum;

wherein the determine the condition indicator from the frequency spectrum comprises:
(a) determine a threshold and a noise floor for the frequency spectrum;
(b) detect peaks of the frequency spectrum over the threshold, each peak having a frequency and a magnitude;
(c) calculate the difference in the frequency between the peaks; and
(d) sum the magnitudes of all peaks with a difference in the frequency equal to a rotational frequency of the component to determine the condition indicator.

17. A non-transitory computer-readable storage medium encoded with instructions that, when executed, cause one or more processors of a computing device to diagnose an anomaly of a monitored component in a drive train to:
obtain original data based only on samples of a tachometer signal;
process the original data to obtain rotational information;
process the original data to produce a sine spectrum;
determine complex magnitudes of the sine spectrum;
remove dominate torsional mode residuals from the complex magnitudes of the sine spectrum to produce a frequency spectrum; and
determine a condition indicator from the frequency spectrum;
wherein the determine the condition indicator from the frequency spectrum comprises:
(a) determine a threshold and a noise floor for the frequency spectrum;
(b) detect peaks of the frequency spectrum over the threshold, each peak having a frequency and a magnitude;
(c) calculate the difference in the frequency between the peaks; and
(d) sum the magnitudes of all peaks with a difference in the frequency equal to a rotational frequency of the component to determine the condition indicator.

Assignees

• Bell Helicopter Textron Inc

Inventors

• Hale Rodney Keith

Classifications

• B64D2045/0085

  Devices for aircraft health monitoring, e.g. monitoring flutter or vibration · CPC title

• B64D45/00 Primary

  Aircraft indicators or protectors not otherwise provided for · CPC title

• B64F5/60

  Testing or inspecting aircraft components or systems · CPC title

• G07C5/002

  Analysing tachograph charts (arrangements for graph-reading in general G06K11/00) · CPC title

• B64C27/12 Primary

  Rotor drives · CPC title