Machine Fault Prediction Based on Analysis of Periodic Information in a Signal
First Claim
1. An apparatus for acquiring and analyzing periodic information in vibration associated with a machine, the apparatus comprising:
- a vibration sensor securely attached to the machine in a location providing a solid transmission path from a source of vibration within the machine to the vibration sensor, the vibration sensor for generating a vibration signal;
a data collector in communication with the vibration sensor, the data collector configured to receive and condition the vibration signal, the data collector comprising;
an analog-to-digital converter for converting the vibration signal to digital vibration data; and
memory for buffering the digital vibration data; and
a periodic information processor operable to receive the digital vibration data, the periodic information processor configured to execute operational instructions for processing the digital vibration data, the operational instructions comprising instructions which, when executed;
generate an original waveform based on the digital vibration data;
perform an autocorrelation function on the original waveform to generate an autocorrelation waveform;
perform a Fast Fourier Transform on the original waveform to generate an original spectrum;
perform a Fast Fourier Transform on the autocorrelation waveform to generate an autocorrelation spectrum;
compile a first list of amplitude peaks from the original spectrum;
compile a second list of amplitude peaks from the autocorrelation spectrum;
match autocorrelation amplitude peaks in the second list with original amplitude peaks in the first list;
add to a peak list each original amplitude peak that matches an autocorrelation amplitude peak;
as original amplitude peaks are added to the peak list, determine a total amount of peak energy associated with the original amplitude peaks in the peak list; and
after the total amount of peak energy associated with the original amplitude peaks in the peak list exceeds a predetermined threshold, generate a periodic information plot comprising the original amplitude peaks in the peak list.
1 Assignment
0 Petitions
Accused Products
Abstract
A “periodic signal parameter” (PSP) indicates periodic patterns in an autocorrelated vibration waveform and potential faults in a monitored machine. The PSP is calculated based on statistical measures derived from an autocorrelation waveform and characteristics of an associated vibration waveform. The PSP provides an indication of periodicity and a generalization of potential fault, whereas characteristics of the associated waveform indicate severity. A “periodic information plot” (PIP) is derived from a vibration signal processed using two analysis techniques to produce two X-Y graphs of the signal data that share a common X-axis. The PIP is created by correlating the Y-values on the two graphs based on the corresponding X-value. The amplitudes of Y-values in the PIP is derived from the two source graphs by multiplication, taking a ratio, averaging, or keeping the maximum value.
-
Citations
36 Claims
-
1. An apparatus for acquiring and analyzing periodic information in vibration associated with a machine, the apparatus comprising:
-
a vibration sensor securely attached to the machine in a location providing a solid transmission path from a source of vibration within the machine to the vibration sensor, the vibration sensor for generating a vibration signal; a data collector in communication with the vibration sensor, the data collector configured to receive and condition the vibration signal, the data collector comprising; an analog-to-digital converter for converting the vibration signal to digital vibration data; and memory for buffering the digital vibration data; and a periodic information processor operable to receive the digital vibration data, the periodic information processor configured to execute operational instructions for processing the digital vibration data, the operational instructions comprising instructions which, when executed; generate an original waveform based on the digital vibration data; perform an autocorrelation function on the original waveform to generate an autocorrelation waveform; perform a Fast Fourier Transform on the original waveform to generate an original spectrum; perform a Fast Fourier Transform on the autocorrelation waveform to generate an autocorrelation spectrum; compile a first list of amplitude peaks from the original spectrum; compile a second list of amplitude peaks from the autocorrelation spectrum; match autocorrelation amplitude peaks in the second list with original amplitude peaks in the first list; add to a peak list each original amplitude peak that matches an autocorrelation amplitude peak; as original amplitude peaks are added to the peak list, determine a total amount of peak energy associated with the original amplitude peaks in the peak list; and after the total amount of peak energy associated with the original amplitude peaks in the peak list exceeds a predetermined threshold, generate a periodic information plot comprising the original amplitude peaks in the peak list. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
-
-
14. An apparatus for acquiring and analyzing periodic information in vibration associated with a machine, the apparatus comprising:
-
a vibration sensor securely attached to the machine in a location providing a solid transmission path from a source of vibration within the machine to the vibration sensor, the vibration sensor for generating a vibration signal; a data collector in communication with the vibration sensor, the data collector configured to receive and condition the vibration signal, the data collector comprising; an analog-to-digital converter for converting the vibration signal to digital vibration data; and memory for buffering the digital vibration data; and a periodic information processor operable to receive the digital vibration data, the periodic information processor configured to execute operational instructions for processing the digital vibration data, the operational instructions comprising instructions which, when executed; generate an original waveform based on the digital vibration data; perform a Fast Fourier Transform on the original waveform to generate an original spectrum having amplitude values YVS(n), where n=1 to N, and N is a number of frequency values; perform an autocorrelation function on the original waveform to generate an autocorrelation waveform; perform a Fast Fourier Transform on the autocorrelation waveform to generate an autocorrelation spectrum having amplitude values YAS(n), where n=1 to N, where N is the number frequency values; combine adjacent pairs of amplitude values YVS(2n) and YVS(2n−
1) in the original spectrum, according to
YMCVS(n)=√
{square root over ((YVS(2n−
1))2+(YVS(2n))2)}; andcombine the original spectrum and the autocorrelation spectrum to generate a periodic information plot having amplitude values YPIP1(n), according to
YPIP1(n)=YMCVS(n)×
YAS(n), where n=1 to N,wherein inclusion of the amplitude values YPIP1(n) in the periodic information plot accentuates signal components that are pertinent to a diagnosis by the analyst while eliminating undesired non-periodic signal components, thereby improving visualization of pertinent signal components. - View Dependent Claims (15, 16, 17, 18, 19)
If YPIP1(n)≦
YTHR,YPIP3(n)=0where n=1 to N, and YTHR is a predetermined threshold value.
-
-
16. The apparatus of claim 14 wherein the periodic information processor is configured to execute operational instructions to perform an inverse Fast Fourier Transform on the periodic information plot to generate an information waveform.
-
17. The apparatus of claim 16 wherein the periodic information processor is configured to execute operational instructions to derive a circular information plot from the information waveform.
-
18. The apparatus of claim 14 wherein the periodic information processor is a component of the data collector.
-
19. The apparatus of claim 14 wherein the periodic information processor is a component of an analyst computer that is in communication with the data collector via a communication network.
-
20. An apparatus for acquiring and analyzing periodic information in vibration associated with a machine, the apparatus comprising:
-
a vibration sensor securely attached to the machine in a location providing a solid transmission path from a source of vibration within the machine to the vibration sensor, the vibration sensor for generating a vibration signal; a data collector in communication with the vibration sensor, the data collector configured to receive and condition the vibration signal, the data collector comprising; an analog-to-digital converter for converting the vibration signal to digital vibration data; and memory for buffering the digital vibration data; and a periodic information processor operable to receive the digital vibration data, the periodic information processor configured to execute operational instructions for processing the digital vibration data, the operational instructions comprising instructions which, when executed; generate an original waveform based on the digital vibration data; perform a Fast Fourier Transform on the original waveform to generate an original spectrum having amplitude values YVS(n), where n=1 to M, and M is a number of frequency values; perform an autocorrelation function on the original waveform to generate an autocorrelation waveform; perform a Fast Fourier Transform on the autocorrelation waveform to generate an autocorrelation spectrum having amplitude values YAS(n), where n=1 to N, where N is the number of frequency values; combine adjacent pairs of amplitude values YVS(2n) and YVS(2n−
1) in the original spectrum, according to
YMCVS(n)=√
{square root over ((YVS(2n−
1))2+(YVS(2n))2)}; andgenerate a periodic information plot having amplitude values YPIP2(n), according to
If YAS(n)>
YTHR, YPIP2(n)=YMCVS(n)
If YAS(n)≦
YTHR, YPIP2(n)=0,where n=1 to N, and YTHR is a predetermined threshold value, wherein inclusion of only the amplitude values YPIP2(n) in the periodic information plot accentuates signal components that are pertinent to a diagnosis by the analyst, while eliminating undesired non-periodic signal components, thereby improving visualization of pertinent signal components. - View Dependent Claims (21, 22)
-
-
23. An apparatus for acquiring and analyzing periodic information in vibration associated with a machine, the apparatus comprising:
-
a vibration sensor securely attached to the machine in a location providing a solid transmission path from a source of vibration within the machine to the vibration sensor, the vibration sensor for generating a vibration signal; a data collector in communication with the vibration sensor, the data collector configured to receive and condition the vibration signal, the data collector comprising; an analog-to-digital converter for converting the vibration signal to digital vibration data; and memory for buffering the digital vibration data; and a periodic information processor operable to receive the digital vibration data, the periodic information processor configured to execute operational instructions for processing the digital vibration data, the operational instructions comprising instructions which, when executed; generate an original waveform based on the digital vibration data; perform a Fast Fourier Transform on the digital vibration data to generate an original spectrum having amplitude values YVS(n), where n=1 to N, where N is a number of frequency values; combine adjacent pairs of amplitude values YVS(2n) and YVS(2n−
1) in the original spectrum, according to
YMCVS(n)=√
{square root over ((YVS(2n−
1))2+(YVS(2n))2)};perform an autocorrelation function on the original waveform to generate an autocorrelation waveform; perform a Fast Fourier Transform on the autocorrelation waveform to generate an autocorrelation spectrum having amplitude values YAS(n), where n=1 to N, where N is the number of frequency values; and combine the original spectrum and the autocorrelation spectrum to generate a periodicity map having coordinate values XPM(n) and YPM(n) determined according to
XPM(n)=YMCVS(n)
YPM(n)=YAS(n)for n=1 to N. - View Dependent Claims (24, 25)
-
-
26. An apparatus for acquiring and analyzing periodic information in vibration associated with a machine, the apparatus comprising:
-
a vibration sensor securely attached to the machine in a location providing a solid transmission path from a source of vibration within the machine to the vibration sensor, the vibration sensor for generating a vibration signal; a data collector in communication with the vibration sensor, the data collector configured to receive and condition the vibration signal, the data collector comprising; an analog-to-digital converter for converting the vibration signal to digital vibration data; and memory for buffering the digital vibration data; and a periodic information processor operable to receive the digital vibration data, the periodic information processor configured to execute operational instructions for processing the digital vibration data, the operational instructions comprising instructions which, when executed; generate an original waveform based on the digital vibration data; perform an autocorrelation function on the original waveform to generate an autocorrelation waveform; perform a Fast Fourier Transform on the autocorrelation waveform to generate an autocorrelation spectrum having amplitude values YAS(n), where n=1 to N; generate a non-periodic information plot having amplitude values YNPIP(n), according to
If YAS(n)<
YTHR, YNPIP(n)=YAS(n)
If YAS(n)≧
YTHR, YNPIP(n)=0,where n=1 to N, and YTHR is a predetermined threshold value, wherein inclusion of only the amplitude values YNPIP(n) in the non-periodic information plot accentuates signal components that are pertinent to a diagnosis by the analyst, while eliminating undesired non-periodic signal components, thereby improving visualization of pertinent signal components. - View Dependent Claims (27, 28)
-
-
29. An apparatus for acquiring and analyzing periodic information in vibration associated with a machine, the apparatus comprising:
-
a vibration sensor securely attached to the machine in a location providing a solid transmission path from a source of vibration within the machine to the vibration sensor, the vibration sensor for generating a vibration signal; a tachometer sensor configured to be attached to the machine and generate a turning speed; a data collector in communication with the vibration sensor and the tachometer sensor, the data collector configured to receive and condition the vibration signal and the turning speed, the data collector comprising; an analog-to-digital converter for converting the vibration signal to digital vibration data; and memory for buffering the digital vibration data; and a periodic information processor operable to receive the digital vibration data, the periodic information processor configured to execute operational instructions for processing the digital vibration data, the operational instructions comprising instructions which, when executed; generate an original waveform based on the digital vibration data; determine a maximum peak amplitude of the original waveform; perform an autocorrelation function on the original waveform to generate an autocorrelation waveform; determine a periodic signal parameter value based at least in part on the autocorrelation waveform, where the periodic signal parameter value comprises a single real number indicative of a level of periodic information in the original waveform; calculate or receive a fault limit level; and calculate one or more severity values based on the maximum peak amplitude and the fault limit level. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36)
-
Specification