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# Comparaison entre les analyses angulaire et temporelle des signaux vibratoires de machines tournantes. Etude du concept de cyclostationnarité floue

Abstract : The aim of this thesis is to exploit as well as possible the cyclostationnarity in order to take advantage of all the information present in signals resulting from rotating machines. The methods presented here are illustrated on gears and rolling elements bearing.

Firstly, the cyclostationnarity and its extensions are introduced. The definitions are made according to the angle where the signals are naturally cyclostationary. Then, the becoming of cyclostationnarity properties after temporal sampling is studied. The cyclic periods are certain according to the angle, but not necessarily according to time because of the random fluctuations of the speed. Consequently, the properties of cyclostationnarity are not necessary valid. So, we introduce the concept of fuzzy cyclostationnarity in order to characterize such a signal. Moreover, in order to induce the cyclostationnarity on the temporal signals, we propose angular domain re-sampling methods.

Secondly, these concepts are applied on mechanical signals. To do so, the concept of cycloergodism is presented. It extends the stationary ergodism to the cyclostationary case and allows to use only one realization. Various tools at the order $1$ and $2$ (variance, Wigner-Ville Distribution) are also shown. An example of diagnosis on gears illustrates the problem caused by commensurable cycles. Then, the pseudo quasi fuzzy cyclostationnarity case is depicted by using a gear box signal with a defective rolling element bearing. In a first time, the separation of the contributions gear and bearings + noise is investigated. The mainly periodic character of the signals of wheel versus the stochastic character of the signals of bearing is exploited. In a second time, the Cyclic Wiener filter is used in order to reduce the noise always present in the bearing contribution.
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https://tel.archives-ouvertes.fr/tel-00103067
Contributor : Frédéric Bonnardot <>
Submitted on : Tuesday, October 3, 2006 - 12:53:37 PM
Last modification on : Wednesday, November 20, 2019 - 2:52:45 AM
Long-term archiving on: : Thursday, September 20, 2012 - 11:10:10 AM

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• HAL Id : tel-00103067, version 1

### Citation

Frédéric Bonnardot. Comparaison entre les analyses angulaire et temporelle des signaux vibratoires de machines tournantes. Etude du concept de cyclostationnarité floue. Traitement du signal et de l'image [eess.SP]. Institut National Polytechnique de Grenoble - INPG, 2004. Français. ⟨tel-00103067⟩

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