US 2026/0259110 A1Published application

Device and method for processing a digital signal

OwnerJames P. LEBLANC, Robert OLLSONinventors

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Abstract

A device (10) for processing a digital signal. The device (10) includes a segmenting means (15), a spectral analysis means (16, 16a, 16b), a first determining means (17), a second determining means (20), a third determining means (21), a Farrow structure (18), an implementing means (24), a fourth determining means (22), and a fifth determining means (23). The device performs machine-health assessment for systems and/or sensors which have no means for direct rotational speed measurement.

Claims12

Dependent claims

A method for processing a continuous signal sampled at a fixed sample rate, the continuous signal being representative of the operation of a rotating element, the rotating element undergoing rotational speed changes, the method comprising:

segmenting the sequential timestamped samples of the digital signal into a plurality of frames and clustering the plurality of frames in a plurality of pairs of frames, each pair of frames comprising a first frame and a second frame so that samples of the second frame are sampled after the samples of the first frame;
for each pair of frames:
(a) performing a spectral analysis of the first frame to determine a first vector comprising frequency bins below or equal to the Nyquist frequency of the sampling of the continuous signal;
(b) performing a spectral analysis of the second frame to determine a second vector comprising frequency bins below or equal to the Nyquist frequency of the sampling of the continuous signal;
(c) determining a first intermediary unit vector comprising the absolute value of at least one frequency bin of the first vector and a second intermediary vector comprising the absolute value of at least one frequency bin of the second vector;
(d) determining a first array of speed change coefficients, each speed change coefficient being representative of an expected speed change of the rotating element;
(e) determining a first initial value from the first array of speed change coefficients;
(f) resampling the frequency bins of the second intermediary vector by a Farrow structure controlled by a first control variable from an original unit index increment representative of the sampling increment of the continuous signal at the fixed sample rate to a first index increment, the second intermediary vector resampled at the first index increment and normalized being a first resulting unit vector, and resampling the frequency bins of the second intermediary vector by the Farrow structure controlled by a second control variable from the original unit index to a second index increment, the second intermediary vector resampled at the second index increment and normalized being a second resulting unit vector, the first and second control variable being determined by an iterative line search method to converge the difference between a first inner product value and a second inner product value toward zero, the initial conditions of the iterative line search method comprising at least the first initial value and a second initial value bigger than the first initial value, the first inner product value being determined from the inner product of the first intermediary unit vector and the first resulting unit vector, and the second inner product value being determined from the inner product of the first intermediary unit vector and the second resulting unit vector;
(g) determining a result value when the difference between the first inner product value and the second inner product value is smaller than a predetermined threshold or the number of iterations of the iterative line search method is equal to a predetermined number of iterations, the result value being equal to the means of the first and second control variables, and storing the result value in a result array and a timestamp value determined from the sequential samples of the said pair of frames;
when the result value of each pair of the plurality of pairs of frames is stored in the result array, determining a correction profile from the result values and timestamp values stored in the result array;
and
resampling the sequential timestamped samples of the continuous signal by the Farrow structure controlled by a third control variable, the third control variable following the correction profile;
and
delivering the resampled sequential timestamped samples of the continuous signal.

11 more elements

A device for processing a digital signal comprising sequential samples of a continuous signal sampled at a fixed sample rate, the continuous signal being representative of the operation of a rotating element, the rotating element undergoing rotational speed changes, the device comprising:

segmenting means configured to segment the sequential timestamped samples of the digital signal into a plurality of frames and to cluster the plurality of frames in a plurality of pairs of frames, each pair of frames comprising a first frame and a second frame so that samples of the second frame are sampled after the samples of the first frame;
spectral analysis means configured to perform a spectral analysis of the first frame to determine a first vector comprising frequency bins below or equal to the Nyquist frequency of the sampling of the continuous signal and a spectral analysis of the second frame to determine a second vector comprising frequency bins below or equal to the Nyquist frequency of the sampling of the continuous signal;
first determining means configured to determine a first intermediary unit vector comprising the absolute value of at least one frequency bin of the first vector and a second intermediary vector comprising the absolute value of at least one frequency bin of the second vector;
second determining means configured to determining a first array of speed change coefficients, each speed change coefficient being representative of an expected speed change of the rotating element;
third determining means configured to determine a first initial value from the first array of speed change coefficients;
a Farrow structure configured to:
be controlled by a first control variable to resample the frequency bins of the second intermediary vector from an original unit index increment representation of the sampling increment of the continuous signal at the fixed sample rate to a first index), the second intermediary vector resampled at the first index increment and normalized being a first resulting unit vector;
be controlled by a second control variable to resample the frequency bins of the second intermediary vector from the original unit index to a second index increment, the second intermediary vector resampled at the second index increment and normalized being a second resulting unit vector;
and
be controlled by a third control variable to resample the sequential timestamped samples of the continuous signal, the third control variable following a correction profile;
implementing means configured to implement an iterative line search method to determine the first and second control variable by converging the difference between a first inner product value and a second inner product value toward zero, the initial conditions of the iterative line search method comprising at least the first initial value and a second initial value bigger than the first initial value, the first inner product value being determined from the inner product of the first intermediary unit vector and the first resulting unit vector, and the second inner product value being determined from the inner product of the first intermediary unit vector and the second resulting unit vector;
fourth determining means configured to determine a result value when the difference between the first inner product value and the second inner product value is smaller than a predetermined threshold or the number of iterations of the iterative line search method is equal to a predetermined number of iterations, the result value being equal to the means of the first and second control variables, and configured to store the result value in a result array and a timestamp value determined from the sequential samples of the said pair of frames;
fifth determining means configured to determine the correction profile from the result values and timestamp values stored in the result array when the result value of each pair of the plurality of pairs of frames is stored in the result array.

10 more elements

Dependencies are inferred from the claim text.

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Abstract

segmenting the sequential timestamped samples of the digital signal into a plurality of frames and clustering the plurality of frames in a plurality of pairs of frames, each pair of frames comprising a first frame and a second frame so that samples of the second frame are sampled after the samples of the first frame;
for each pair of frames:
(a) performing a spectral analysis of the first frame to determine a first vector comprising frequency bins below or equal to the Nyquist frequency of the sampling of the continuous signal;
(b) performing a spectral analysis of the second frame to determine a second vector comprising frequency bins below or equal to the Nyquist frequency of the sampling of the continuous signal;
(c) determining a first intermediary unit vector comprising the absolute value of at least one frequency bin of the first vector and a second intermediary vector comprising the absolute value of at least one frequency bin of the second vector;
(d) determining a first array of speed change coefficients, each speed change coefficient being representative of an expected speed change of the rotating element;
(e) determining a first initial value from the first array of speed change coefficients;
(f) resampling the frequency bins of the second intermediary vector by a Farrow structure controlled by a first control variable from an original unit index increment representative of the sampling increment of the continuous signal at the fixed sample rate to a first index increment, the second intermediary vector resampled at the first index increment and normalized being a first resulting unit vector, and resampling the frequency bins of the second intermediary vector by the Farrow structure controlled by a second control variable from the original unit index to a second index increment, the second intermediary vector resampled at the second index increment and normalized being a second resulting unit vector, the first and second control variable being determined by an iterative line search method to converge the difference between a first inner product value and a second inner product value toward zero, the initial conditions of the iterative line search method comprising at least the first initial value and a second initial value bigger than the first initial value, the first inner product value being determined from the inner product of the first intermediary unit vector and the first resulting unit vector, and the second inner product value being determined from the inner product of the first intermediary unit vector and the second resulting unit vector;
(g) determining a result value when the difference between the first inner product value and the second inner product value is smaller than a predetermined threshold or the number of iterations of the iterative line search method is equal to a predetermined number of iterations, the result value being equal to the means of the first and second control variables, and storing the result value in a result array and a timestamp value determined from the sequential samples of the said pair of frames;
when the result value of each pair of the plurality of pairs of frames is stored in the result array, determining a correction profile from the result values and timestamp values stored in the result array;
and
resampling the sequential timestamped samples of the continuous signal by the Farrow structure controlled by a third control variable, the third control variable following the correction profile;
and
delivering the resampled sequential timestamped samples of the continuous signal.

11 more elements