US 11,927,501 B2
Method and device for monitoring a gear system
Dany Abboud, Moissy-Cramayel (FR); Mohamed El Badaoui, Moissy-Cramayel (FR); and Yosra Marnissi, Moissy-Cramayel (FR)
Assigned to SAFRAN, Paris (FR)
Appl. No. 17/050,275
Filed by SAFRAN, Paris (FR)
PCT Filed Apr. 19, 2019, PCT No. PCT/FR2019/050945
§ 371(c)(1), (2) Date Oct. 23, 2020,
PCT Pub. No. WO2019/207242, PCT Pub. Date Oct. 31, 2019.
Claims priority of application No. 1853561 (FR), filed on Apr. 24, 2018.
Prior Publication US 2021/0239570 A1, Aug. 5, 2021
Int. Cl. F03D 7/02 (2006.01); G01M 13/028 (2019.01); G06F 17/14 (2006.01)
CPC G01M 13/028 (2013.01) [G06F 17/141 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A method for monitoring a gear system (1), the gear system (1) comprising at least two wheels, each wheel being configured to rotate at a rotational frequency, the method comprising the steps of
measuring and acquiring by means of an acquisition measuring unit comprising a sensor a vibratory or acoustic digital signal noted x(t) containing a representation of the vibrations of the gear system; the sensor being an accelerometer or a microphone;
the method comprising, for each rotational frequency of each wheel, the steps of:
filtering, by means of a filter, the vibratory or acoustic digital signal for obtaining an image monitoring signal containing at least one vibratory component of at least one fault;
computing the square envelope of the image monitoring signal, defined by the squared absolute value of the Hilbert transform of the image monitoring signal to extract an image of the modulating signals associated with the rotation of the wheels from the image monitoring signal;
computing the synchronous average of the square envelope with respect to a period of rotation of a wheel of interest chosen among the wheels of the gear, the synchronous average of the square envelope attenuating spurious components in the envelope coming from other mechanical sources;
computing the square root of the synchronous average normalized by the median value of the synchronous average for obtaining a monitoring indicator as a function of the synchronous average;
comparing the variation of the monitoring indicator to a reference for detecting at least one fault.