Safran

Mohamed El Badaoui

Dany Abboud

Yosra Marnissi

Axel Barrau

Elisa Hubert

The invention concerns a method for monitoring a gear system () comprising at least two wheels, each wheel having a characteristic frequency (f, f), a vibratory or acoustic signal representative of these vibrations having been acquired by a sensor (), a vibratory or acoustic digital signal x(t) having been obtained, the method comprising, for each characteristic frequency of the system (), the steps of filtering (E) 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 (E) 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 (E) 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 average helping attenuate spurious components in the envelope originating from other mechanical sources; determining (E) a monitoring indicator dependent on said synchronous average, said monitoring indicator being defined by the square root of the synchronous average normalised by the median value of the synchronous average.

Method and device for monitoring a gear system

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.

Method for detecting a defect in a vibration sensor, associated device and computer program

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&#x394; t+&#x3c4; n, the samples and the sampling times t n being stored in the memory.

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Moissy-Cramayel, France

Mohamed El Badaoui