US5483833A
Expired / Lapsed
US
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Method and apparatus for monitoring aircraft components
Assignee: Lockheed Martin Energy Systems Inc
•
Filing: 1994-03-22
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Granted: 1996-01-16
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Expires: 2014-03-22
Abstract
Abstract Operability of aircraft mechanical components is monitored by analyzing the voltage output of an electrical generator of the aircraft. Alternative generators, for a turbine-driven rotor aircraft, include the gas producer turbine tachometer generator, the power turbine tachometer generator, and the aircraft systems power producing starter/generator. Changes in the peak amplitudes of the fundamental frequency and its harmonics are correlated to changes in condition of the mechanical components.
Inventors
- 👤 Larry M. Dickens
- 👤 Howard D. Haynes
- 👤 Curtis W. Ayers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 22:27
CPC Classifications
G; G01; G01H; G01H1/00; G01H1/003; G01M; G01M15/00; G01M15/04; G01M15/12
Claims Analysis
Total Claims: 38
Claim 1
Independent Claim
108 words
An apparatus for monitoring an aircraft having a mechanical system and an electrical system, comprising: means for obtaining an electrical signal from a component of the electrical system, the electrical signal varying in accordance with movement of at least one component of the mechanical system; and means for correlating changes in the electrical signal to changes in condition of the at least one component, wherein the electrical signal is a voltage signal, and wherein the means for producing the voltage signal comprises at least one of a gas producer turbine tachometer generator, a power turbine tachometer generator, a rotor tachometer generator, and an aircraft systems power producing starter/generator.
Claim 2
Independent Claim
108 words
An apparatus for monitoring an aircraft having a mechanical system and an electrical system, comprising: means for obtaining an electrical signal from a component of the electrical system, the electrical signal varying in accordance with movement of at least one component of the mechanical system; and means for correlating changes in the electrical signal to changes in condition of the at least one component, wherein the electrical signal is a voltage signal, and wherein the means for producing the voltage signal comprises at least one of a gas producer turbine tachometer generator, a power turbine tachometer generator, a rotor tachometer generator, and an aircraft systems power producing starter/generator.
Claim 3
Dependent Claim
56 words
An apparatus according to claim 1, wherein the electrical signal is a voltage signal and wherein the correlating means includes means for producing a frequency-domain spectrum of the voltage signal during operation of the aircraft, the voltage signal exhibiting a fundamental frequency having a peak amplitude, and a plurality of harmonics, each having a peak amplitude.
Claim 4
Dependent Claim
52 words
An apparatus according to claim 2, wherein the correlating means includes means for determining a baseline fundamental frequency having a corresponding peak amplitude, means for monitoring the fundamental frequency and its corresponding peak amplitude during operation of the aircraft, and means for comparing the monitored peak amplitude to the baseline peak amplitude.
Claim 5
Dependent Claim
21 words
An apparatus according to claim 3, wherein the means for producing a voltage signal comprises an aircraft systems power producing starter/generator.
Claim 6
Dependent Claim
34 words
An apparatus according to claim 2, wherein the correlating means includes means for determining changes in the peak amplitudes of the harmonic frequencies relative to changes in the peak amplitude of the fundamental frequency.
Claim 7
Dependent Claim
27 words
An apparatus according to claim 2, wherein the correlating means includes means for determining changes in relative harmonic peak magnitude for at least the first several harmonics.
Claim 8
Dependent Claim
93 words
An apparatus according to claim 5, wherein the correlating means includes means for determining a baseline fundamental frequency having a corresponding peak amplitude, and baseline harmonics, each having a corresponding peak amplitude, means for monitoring, during operation of the aircraft, the fundamental frequency and its corresponding peak amplitude, and the harmonics, each having a corresponding peak amplitude, means for normalizing the monitored and baseline fundamental and harmonic peak amplitudes, and means for determining a ratio of the baseline normalized fundamental and harmonic peak amplitudes to the monitored normalized fundamental and harmonic peak amplitudes.
Claim 9
Dependent Claim
26 words
An apparatus according to claim 7, further comprising means for determining an average change in relative harmonic peak magnitudes for at least the first several harmonics.
Claim 10
Dependent Claim
13 words
An apparatus according to claim 1, wherein the correlating means comprises a computer.
Claim 11
Dependent Claim
23 words
An apparatus according to claim 8, further comprising a voltage splitter disposed between the computer and the means for producing a voltage signal.
Claim 12
Dependent Claim
36 words
An apparatus according to claim 1, wherein the electrical signal is a voltage signal, and wherein the apparatus further comprises signal conditioning means, disposed between the means for obtaining the voltage signal and the correlating means.
Claim 13
Dependent Claim
19 words
An apparatus according to claim 11, wherein the signal conditioning means comprises a high pass filter and an amplifier.
Claim 14
Dependent Claim
61 words
An apparatus according to claim 1, wherein the electrical signal is a voltage signal, and wherein the correlating means includes means for filtering the voltage signal, means for RMS-to-DC demodulating the filtered voltage signal, means for performing a fast Fourier transform (FFT) on the demodulated voltage signal, and means for comparing baseline specific frequency peaks to frequency peaks from the FFT.
Claim 15
Dependent Claim
59 words
An apparatus according to claim 1, wherein the electrical signal is a voltage signal, and wherein the correlating means includes means for performing a fast Fourier transform (FFT) on the voltage signal, means for performing digital mathematical frequency shifting on the FFT, and means for comparing baseline specific frequency peaks to frequency peaks from the mathematically frequency shifted FFT.
Claim 16
Dependent Claim
54 words
An apparatus according to claim 1, wherein the electrical signal is a voltage signal and wherein the correlating means includes means for RMS-to-DC demodulating the voltage signal, means for performing a fast Fourier transform (FFT) on the demodulated voltage signal, and means for comparing baseline specific frequency peaks to frequency peaks from the FFT.
Claim 17
Independent Claim
153 words
A method for monitoring an aircraft having a mechanical system and an electrical system, comprising the steps of: obtaining an electrical signal from a component of the electrical system, the electrical signal varying in accordance with movement of at least one component of the mechanical system; and correlating changes in the electrical signal to changes in condition of the at least one component, wherein the electrical signal is a voltage signal and wherein the correlating step includes producing a frequency-domain spectrum of the voltage signal during operation of the aircraft, the voltage signal exhibiting a fundamental frequency having a peak amplitude, and a plurality of harmonics, each having a peak amplitude, and wherein the correlating step further includes determining a baseline fundamental frequency having a corresponding peak amplitude, monitoring the fundamental frequency and its corresponding peak amplitude during operation of the aircraft, and comparing the monitored peak amplitude to the baseline peak amplitude.
Claim 18
Independent Claim
153 words
A method for monitoring an aircraft having a mechanical system and an electrical system, comprising the steps of: obtaining an electrical signal from a component of the electrical system, the electrical signal varying in accordance with movement of at least one component of the mechanical system; and correlating changes in the electrical signal to changes in condition of the at least one component, wherein the electrical signal is a voltage signal and wherein the correlating step includes producing a frequency-domain spectrum of the voltage signal during operation of the aircraft, the voltage signal exhibiting a fundamental frequency having a peak amplitude, and a plurality of harmonics, each having a peak amplitude, and wherein the correlating step further includes determining a baseline fundamental frequency having a corresponding peak amplitude, monitoring the fundamental frequency and its corresponding peak amplitude during operation of the aircraft, and comparing the monitored peak amplitude to the baseline peak amplitude.
Claim 19
Dependent Claim
25 words
A method according to claim 16, wherein the step of producing a voltage signal comprises attaching a lead to an aircraft systems power producing starter/generator.
Claim 20
Dependent Claim
32 words
A method according to claim 16, wherein the correlating step includes determining changes in the peak amplitudes of the harmonic frequencies relative to changes in the peak amplitude of the fundamental frequency.
Claim 21
Dependent Claim
25 words
A method according to claim 16, wherein the correlating step includes determining changes in relative harmonic peak magnitude for at least the first several harmonics.
Claim 22
Dependent Claim
85 words
A method according to claim 19, wherein the correlating step includes determining a baseline fundamental frequency having a corresponding peak amplitude, and baseline harmonics, each having a corresponding peak amplitude, monitoring, during operation of the aircraft, the fundamental frequency and its corresponding peak amplitude, and the harmonics, each having a corresponding peak amplitude, normalizing the monitored and baseline fundamental and harmonic peak amplitudes, and determining a ratio of the baseline normalized fundamental and harmonic peak amplitudes to the monitored normalized fundamental and harmonic peak amplitudes.
Claim 23
Independent Claim
87 words
A method for monitoring an aircraft mechanical system, comprising the steps of: producing a voltage signal which varies in accordance with movement of at least one component of the mechanical system; and correlating changes in the voltage signal to changes in condition of the at least one component, wherein the step of producing a voltage signal comprises attaching a lead to at least one of a gas producer turbine tachometer generator, a power turbine tachometer generator, a rotor tachometer generator, and an aircraft systems power producing starter/generator.
Claim 24
Independent Claim
87 words
A method for monitoring an aircraft mechanical system, comprising the steps of: producing a voltage signal which varies in accordance with movement of at least one component of the mechanical system; and correlating changes in the voltage signal to changes in condition of the at least one component, wherein the step of producing a voltage signal comprises attaching a lead to at least one of a gas producer turbine tachometer generator, a power turbine tachometer generator, a rotor tachometer generator, and an aircraft systems power producing starter/generator.
Claim 25
Independent Claim
152 words
An apparatus for monitoring an aircraft having a mechanical system and an electrical system, comprising: means for obtaining an electrical signal from a component of the electrical system, the electrical signal varying in accordance with movement of at least one component of the mechanical system; and means for correlating changes in the electrical signal to changes in condition of the at least one component, wherein the correlating means includes means for producing a frequency-domain spectrum of a voltage signal during operation of the aircraft, the voltage signal exhibiting a fundamental frequency having a peak amplitude, and a plurality of harmonics, each having a peak amplitude, and wherein the correlating means includes means for determining a baseline fundamental frequency having a corresponding peak amplitude, means for monitoring the fundamental frequency and its corresponding peak amplitude during operation of the aircraft, and means for comparing the monitored peak amplitude to the baseline peak amplitude.
Claim 26
Independent Claim
152 words
An apparatus for monitoring an aircraft having a mechanical system and an electrical system, comprising: means for obtaining an electrical signal from a component of the electrical system, the electrical signal varying in accordance with movement of at least one component of the mechanical system; and means for correlating changes in the electrical signal to changes in condition of the at least one component, wherein the correlating means includes means for producing a frequency-domain spectrum of a voltage signal during operation of the aircraft, the voltage signal exhibiting a fundamental frequency having a peak amplitude, and a plurality of harmonics, each having a peak amplitude, and wherein the correlating means includes means for determining a baseline fundamental frequency having a corresponding peak amplitude, means for monitoring the fundamental frequency and its corresponding peak amplitude during operation of the aircraft, and means for comparing the monitored peak amplitude to the baseline peak amplitude.
Claim 27
Independent Claim
133 words
An apparatus for monitoring an aircraft having a mechanical system and an electrical system, comprising: means for obtaining an electrical signal from a component of the electrical system, the electrical signal varying in accordance with movement of at least one component of the mechanical system; and means for correlating changes in the electrical signal to changes in condition of the at least one component, wherein the correlating means includes means for producing a frequency-domain spectrum of voltage signal during operation of the aircraft, the voltage signal exhibiting a fundamental frequency having a peak amplitude, and a plurality of harmonics, each having a peak amplitude, and wherein the correlating means includes means for determining changes in the peak amplitudes of the harmonic frequencies relative to changes in the peak amplitude of the fundamental frequency.
Claim 28
Independent Claim
133 words
An apparatus for monitoring an aircraft having a mechanical system and an electrical system, comprising: means for obtaining an electrical signal from a component of the electrical system, the electrical signal varying in accordance with movement of at least one component of the mechanical system; and means for correlating changes in the electrical signal to changes in condition of the at least one component, wherein the correlating means includes means for producing a frequency-domain spectrum of voltage signal during operation of the aircraft, the voltage signal exhibiting a fundamental frequency having a peak amplitude, and a plurality of harmonics, each having a peak amplitude, and wherein the correlating means includes means for determining changes in the peak amplitudes of the harmonic frequencies relative to changes in the peak amplitude of the fundamental frequency.
Claim 29
Independent Claim
127 words
An apparatus for monitoring an aircraft having a mechanical system and an electrical system, comprising: means for obtaining an electrical signal from a component of the electrical system, the electrical signal varying in accordance with movement of at least one component of the mechanical system; and means for correlating changes in the electrical signal to changes in condition of the at least one component, wherein the correlating means includes means for producing a frequency-domain spectrum of a voltage signal during operation of the aircraft, the voltage signal exhibiting a fundamental frequency having a peak amplitude, and a plurality of harmonics, each having a peak amplitude, and wherein the correlating means includes means for determining changes in relative harmonic peak magnitude for at least the first several harmonics.
Claim 30
Independent Claim
127 words
An apparatus for monitoring an aircraft having a mechanical system and an electrical system, comprising: means for obtaining an electrical signal from a component of the electrical system, the electrical signal varying in accordance with movement of at least one component of the mechanical system; and means for correlating changes in the electrical signal to changes in condition of the at least one component, wherein the correlating means includes means for producing a frequency-domain spectrum of a voltage signal during operation of the aircraft, the voltage signal exhibiting a fundamental frequency having a peak amplitude, and a plurality of harmonics, each having a peak amplitude, and wherein the correlating means includes means for determining changes in relative harmonic peak magnitude for at least the first several harmonics.
Claim 31
Independent Claim
88 words
An apparatus for monitoring an aircraft having a mechanical system and an electrical system, comprising: means for obtaining an electrical signal from a component of the electrical system, the electrical signal varying in accordance with movement of at least one component of the mechanical system; means for correlating changes in the electrical signal to changes in condition of the at least one component, wherein the electrical signal is a voltage signal; and signal conditioning means disposed between the means for obtaining a voltage signal and the correlating means.
Claim 32
Independent Claim
88 words
An apparatus for monitoring an aircraft having a mechanical system and an electrical system, comprising: means for obtaining an electrical signal from a component of the electrical system, the electrical signal varying in accordance with movement of at least one component of the mechanical system; means for correlating changes in the electrical signal to changes in condition of the at least one component, wherein the electrical signal is a voltage signal; and signal conditioning means disposed between the means for obtaining a voltage signal and the correlating means.
Claim 33
Independent Claim
118 words
An apparatus for monitoring an aircraft having a mechanical system and an electrical system, comprising; means for obtaining an electrical signal from a component of the electrical system, the electrical signal varying in accordance with movement of at least one component of the mechanical system; means for correlating changes in the electrical signal to changes in condition of the at least one component, wherein the electrical signal is a voltage signal, and wherein the correlating means includes means for filtering the voltage signal, means for RMS-to-DC demodulating the filtered voltage signal, means for performing a fast Fourier transform (FFT) on the demodulated voltage signa, and means for comparing baseline specific frequency peaks to frequency peaks from the FFT.
Claim 34
Independent Claim
118 words
An apparatus for monitoring an aircraft having a mechanical system and an electrical system, comprising; means for obtaining an electrical signal from a component of the electrical system, the electrical signal varying in accordance with movement of at least one component of the mechanical system; means for correlating changes in the electrical signal to changes in condition of the at least one component, wherein the electrical signal is a voltage signal, and wherein the correlating means includes means for filtering the voltage signal, means for RMS-to-DC demodulating the filtered voltage signal, means for performing a fast Fourier transform (FFT) on the demodulated voltage signa, and means for comparing baseline specific frequency peaks to frequency peaks from the FFT.
Claim 35
Independent Claim
116 words
An apparatus for monitoring an aircraft having a mechanical system and an electrical system, comprising; means for obtaining an electrical signal from a component of the electrical system, the electrical signal varying in accordance with movement of at least one component of the mechanical system; means for correlating changes in the electrical signal to changes in condition of the at least one component, wherein the electrical signal is a voltage signal, and wherein the correlating means includes means for performing a fast Fourier transform (FFT) on the voltage signal, means for performing digital mathematical frequency shifting on the FFT, and means for comparing baseline specific frequency peaks to frequency peaks from the mathematically frequency shifted FFT.
Claim 36
Independent Claim
116 words
An apparatus for monitoring an aircraft having a mechanical system and an electrical system, comprising; means for obtaining an electrical signal from a component of the electrical system, the electrical signal varying in accordance with movement of at least one component of the mechanical system; means for correlating changes in the electrical signal to changes in condition of the at least one component, wherein the electrical signal is a voltage signal, and wherein the correlating means includes means for performing a fast Fourier transform (FFT) on the voltage signal, means for performing digital mathematical frequency shifting on the FFT, and means for comparing baseline specific frequency peaks to frequency peaks from the mathematically frequency shifted FFT.
Claim 37
Independent Claim
111 words
An apparatus for monitoring an aircraft having a mechanical system and an electrical system, comprising: means for obtaining an electrical signal from a component of the electrical system, the electrical signal varying in accordance with movement of at least one component of the mechanical system; means for correlating changes in the electrical signal to changes in condition of the at least one component, wherein the electrical signal is a voltage signal, and wherein the correlating means includes means for RMS-to-DC demodulating the voltage signal, means for performing a fast Fourier transform (FFT) on the demodulated voltage signal, and means for comparing baseline specific frequency peaks to frequency peaks from the FFT.
Claim 38
Independent Claim
111 words
An apparatus for monitoring an aircraft having a mechanical system and an electrical system, comprising: means for obtaining an electrical signal from a component of the electrical system, the electrical signal varying in accordance with movement of at least one component of the mechanical system; means for correlating changes in the electrical signal to changes in condition of the at least one component, wherein the electrical signal is a voltage signal, and wherein the correlating means includes means for RMS-to-DC demodulating the voltage signal, means for performing a fast Fourier transform (FFT) on the demodulated voltage signal, and means for comparing baseline specific frequency peaks to frequency peaks from the FFT.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-01-15 | 1999-07-17 | 2000-01-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-01-15 | 2003-07-17 | 2004-01-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-01-15 | 2007-07-17 | 2008-01-16 | $7700.00 | Window Closed / Lapsed |