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.