Abstract: A method for monitoring the engine speed of a rotating machine, includes constructing a raw spectrogram from a vibratory signal; denoising the spectrogram to obtain an equalised spectrogram, the denoising including a first sub-procedure of determining a foot of the spectrogram, the foot of the spectrum being a set of random harmonic components contained in the raw spectrogram, the first sub-procedure including a first sub-sub-procedure of constructing a regression function robust to the peaks of the spectrogram, the regression function being applied to a logarithm of the spectrogram or to the spectrogram; a second sub-sub-procedure of determining the foot of the spectrum from the regression function; a second sub-procedure of determining the equalised spectrogram from the foot of the spectrogram; separating sources in the equalised spectrogram by determining an estimator of the frequencies of interest; determining an instantaneous speed of rotation of the engine speed from the estimator.

Abstract: A method for monitoring a rotary mechanical system of an aircraft including in particular the steps of determining an estimated power spectral density (V) of a noise (v) from a signal (x) representative of vibrations of the rotary mechanical system, determining an equalized power spectral density (Q) by dividing the estimated power spectral density (X) of the signal (x) by the estimated power spectral density (V) of the noise (v), extracting peaks (Qdet) from the equalized power spectral density (Q), and identifying a failure in the rotary mechanical system from the extracted peaks.

Abstract: A method for detecting a defect in a bearing of a rotating system, includes acquiring a bearing position signal, a vibratory signal from the bearing and a theoretical characteristic vector of the bearing; determining a deterministic part of the vibratory signal and removing the deterministic part to obtain a residual signal function of the position signal; calculating, from the theoretical characteristic vector, lower and upper bounds of defect frequencies; calculating, from the vibratory signal, a spectral coherence and the square of the amplitude of the spectral coherence; calculating, from the square of the amplitude of the spectral coherence and the lower and upper bounds of the defect frequencies, a current characteristic vector of the bearing; determining a spectral cyclic contrast of the defect; finely identifying signatures of interest by calculating a weighted integrated cyclic coherence associated with the defect, and determining diagnostic indicators easily interpretable by an operator.

Abstract: A method for monitoring a turbine engine, said method including, for at least one blade of a rotor with which the turbine engine is equipped, the steps of: obtaining a plurality of samples of at least one analogue time signal acquired by means of at least one fixed proximity sensor and representing a passage of said at least one blade in front of said at least one proximity sensor; calculating a deflection of said at least one blade for each of said samples: determining, in the form of a linear combination of sinusoidal signals, a so-called “approximation signal”, minimizing a cost function evaluating a deviation between said calculated deflections and said approximation signal; and monitoring the vibratory behavior of said at least one blade on the basis of frequencies and/or amplitudes and/or phases of the sinusoidal signals that make up said approximation signal.

Abstract: Method for monitoring a turbomachine comprising a stator and a rotor, device, system, aircraft and computer program product. The method comprises a step of acquiring an input signal which represents a deformation of the stator or rotor of the turbomachine. The input signal has been acquired by a deformation gauge which is attached to the stator or rotor. The input signal comprises a first component which represents deformations of the stator or rotor which are caused by rotation of the rotor vanes in relation to the stator, and a second component which represents deformations which are caused by different elements of the rotor vanes. The method comprises a step of re-sampling the input signal in order to obtain a re-sampled input signal comprising a predefined whole number of samples per revolution of the turbomachine rotor.

Abstract: The present invention relates to a method for estimating a speed (v) of movement of a wheeled vehicle, wherein a frequency trajectory (?t) representative of the speed (v) of a wheel (RO) of the vehicle (VE) in a filtered spectrogram (S(ft, t)) is estimated (E5) as follows: a probability (pZt|?t) of observation of the trajectory (ft) is estimated (E51) on the basis of a computed amplitude of the filtered spectrogram (S(ft, t)), an a posteriori observation law (pZt|?t) proportional to the product of the probability (p?) and of the probability (p?|Z)? is estimated (E52), the trajectory (ft) is estimated (E53) on the basis of the law (p?|Z), and the speed (v) of movement of the wheel of the vehicle is estimated (E6) on the basis of the trajectory (?t).

Abstract: The invention relates to a method for monitoring the state of mechanical components such as bearings and gears on a shaft line equipping a rotating machine. Said method includes a step of obtaining at least one measurement yc[k] of the absolute acceleration of the shaft, as well as a set of steps of: obtaining a value fr[k] of the rotational frequency of the shaft, determining a matrix H[k] making it possible to define a state model described by: [k+1]=x[k]+w[k]etY[k]=[(y_c [k])¦SE[k]]=H[k]×x[k]+v[k], determining an estimator of the vector x[k] based on data from the state model, said set of steps further including, for at least one mechanical component, steps of: determining, from said estimator, a quantity characteristic of a contribution of said component to the vector Y[k], comparing said quantity with a threshold, detecting a possible defect of said at least one mechanical component.

Abstract: The invention concerns a method for monitoring a gear system (1) comprising at least two wheels, each wheel having a characteristic frequency (f1, f2), a vibratory or acoustic signal representative of these vibrations having been acquired by a sensor (21), a vibratory or acoustic digital signal x(t) having been obtained, the method comprising, for each characteristic frequency of the system (1), the steps of filtering (E1) the digital signal by means of a filter in such a way as to obtain an image monitoring signal of at least one vibratory component of at least one defect; determining (E3) the square envelope of said monitoring signal, defined by the square absolute value of the Hilbert transform of the monitoring signal so as to extract an image of the modulating signals associated with the rotation of the wheels from the monitoring signal; determining (E4) the synchronous average of said square envelope relative to the period of rotation of a wheel of interest chosen from the wheels of the gear, said avera

Abstract: The invention relates to a method (1) for monitoring a rotating machine (100) of an aircraft, wherein a measurement signal is acquired from the rotating machine. According to the invention, instantaneous frequencies (fK(t)) of sinusoidal components of the measurement signal are estimated, and, using a computing module (12), a plurality of successive iterations are carried out in each of which: complex envelopes of the components are updated (C1), parameters of a model of a noise of the signal are updated (C21) on the basis of the envelopes, whether the model has converged from the preceding iteration to the present iteration is tested (C4), with a view to: o if not, carrying out a new iteration, o if so, performing a computation (D) of the complex envelopes on the basis of the iterations that have been carried out.

Abstract: Method for monitoring a turbomachine comprising a stator and a rotor, device, system, aircraft and computer program product. The method comprises a step of acquiring an input signal which represents a deformation of the stator or rotor of the turbomachine. The input signal has been acquired by a deformation gauge which is attached to the stator or rotor. The input signal comprises a first component which represents deformations of the stator or rotor which are caused by rotation of the rotor vanes in relation to the stator, and a second component which represents deformations which are caused by different elements of the rotor vanes. The method comprises a step of re-sampling the input signal in order to obtain a re-sampled input signal comprising a predefined whole number of samples per revolution of the turbomachine rotor.

Abstract: The invention relates to a method (1) for monitoring a rotating machine (100) of an aircraft, wherein a measurement signal is acquired from the rotating machine. According to the invention, instantaneous frequencies (fK(t)) of sinusoidal components of the measurement signal are estimated, and, using a computing module (12), a plurality of successive iterations are carried out in each of which: complex envelopes of the components are updated (C1), parameters of a model of a noise of the signal are updated (C21) on the basis of the envelopes, whether the model has converged from the preceding iteration to the present iteration is tested (C4), with a view to: o if not, carrying out a new iteration, o if so, performing a computation (D) of the complex envelopes on the basis of the iterations that have been carried out.

Abstract: A method detects a defect in a vibration sensor including the whitening of the vibratory signal delivered by the vibration sensor, and the calculation of an indicator of asymmetry of the whitened vibratory signal. The whitening may be a cepstral whitening implemented simply by dividing the Fourier transform of the signal by its modulus. The asymmetry indicator is a counter of aberrant points in the whitened vibratory signal.

Abstract: A method includes obtaining a vibration signal acquired by an accelerometer sensor; eliminating a deterministic component of the vibration signal; obtaining, for a determined defect, a characteristic theoretical frequency of this defect and a determined maximum deviation around this theoretical frequency; computing, as a function of a cyclic frequency, an integrated cyclic coherence of the processed vibration signal; estimating an actual frequency of the defect on the basis of the integrated cyclic coherence, of the theoretical frequency of the defect and of the maximum deviation; computing a diagnostic indicator of the defect by summing M integrated cyclic coherences of the vibration signal evaluated as M cyclic frequencies respectively equal to M harmonics of the estimated actual frequency of the defect; comparing the diagnostic indicator of the defect with a predetermined threshold, and in the event of it being exceeded, detecting the defect on the bearing.

Abstract: The invention relates to an acquisition module for a monitoring system of a rotating machine, in particular of an aircraft engine, the acquisition module comprising at least one measurement sensor for measuring an analogue signal x(t) of a physical quantity of a member of the rotating machine, at least one sample-and-hold device configured to collect a sample of the analogue signal x(t) at sampling times t n and to maintain it constant between two sampling times t n, and at least one memory for storing samples, the sample-and-hold device being configured to collect a sample of the analogue signal x(t) at sampling times t n defined in a random manner, the sampling times t n being defined according to the following law t n=n? t+? n, the samples and the sampling times t n being stored in the memory.

Abstract: The invention concerns a method for monitoring a gear system (1) comprising at least two wheels, each wheel having a characteristic frequency (f1, f2), a vibratory or acoustic signal representative of these vibrations having been acquired by a sensor (21), a vibratory or acoustic digital signal x(t) having been obtained, the method comprising, for each characteristic frequency of the system (1), the steps of filtering (E1) the digital signal by means of a filter in such a way as to obtain an image monitoring signal of at least one vibratory component of at least one defect; determining (E3) the square envelope of said monitoring signal, defined by the square absolute value of the Hilbert transform of the monitoring signal so as to extract an image of the modulating signals associated with the rotation of the wheels from the monitoring signal; determining (E4) the synchronous average of said square envelope relative to the period of rotation of a wheel of interest chosen from the wheels of the gear, said avera

Abstract: The invention relates to an acquisition module for a monitoring system of a rotating machine, in particular of an aircraft engine, the acquisition module comprising at least one measurement sensor for measuring an analogue signal x(t) of a physical quantity of a member of the rotating machine, at least one sample-and-hold device configured to collect a sample of the analogue signal x(t) at sampling times t n and to maintain it constant between two sampling times t n, and at least one memory for storing samples, the sample-and-hold device being configured to collect a sample of the analogue signal x(t) at sampling times t n defined in a random manner, the sampling times t n being defined according to the following law t n=n? t+? n, the samples and the sampling times t n being stored in the memory.

Abstract: A method includes obtaining a vibration signal acquired by an accelerometer sensor; eliminating a deterministic component of the vibration signal; obtaining, for a determined defect, a characteristic theoretical frequency of this defect and a determined maximum deviation around this theoretical frequency; computing, as a function of a cyclic frequency, an integrated cyclic coherence of the processed vibration signal; estimating an actual frequency of the defect on the basis of the integrated cyclic coherence, of the theoretical frequency of the defect and of the maximum deviation; computing a diagnostic indicator of the defect by summing M integrated cyclic coherences of the vibration signal evaluated as M cyclic frequencies respectively equal to M harmonics of the estimated actual frequency of the defect; comparing the diagnostic indicator of the defect with a predetermined threshold, and in the event of it being exceeded, detecting the defect on the bearing.

Abstract: A method detects a defect in a vibration sensor including the whitening of the vibratory signal delivered by the vibration sensor, and the calculation of an indicator of asymmetry of the whitened vibratory signal. The whitening may be a cepstral whitening implemented simply by dividing the Fourier transform of the signal by its modulus. The asymmetry indicator is a counter of aberrant points in the whitened vibratory signal.