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Impact of pulse time uncertainty on synchronous average: Statistical analysis and relevance to rotating machinery diagnosis

Camerini, Valerio and Coppotelli, Giuliano and Bendisch, Stefan and Kiehn, Daniel (2019) Impact of pulse time uncertainty on synchronous average: Statistical analysis and relevance to rotating machinery diagnosis. Mechanical Systems and Signal Processing (MSSP), 129, pp. 308-336. Elsevier. DOI: 10.1016/j.ymssp.2019.04.017 ISSN 0888-3270

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Official URL: https://www.sciencedirect.com/science/article/pii/S0888327019302481

Abstract

Time synchronous averaging for the extraction of periodic waveforms is a rather common processing method for rotating machinery diagnosis. By synchronizing the signal to the rotational angle of the component of interest, e.g. by using keyphasor reference signal, it is possible to perform the averaging in the angular domain, thus obtaining an anglesynchronous signal. Jittering of the reference signal affects the quality of the synchronous averaging process, resulting in attenuation and uncertain estimation of the extracted synchronous signal, especially in the high frequency band. In this paper, the effects of random uncertainty in the pulse arrival times of the reference signal on the synchronous averaging method are studied, with the objective of assessing the relevance of such a jitter error to the extracted waveform and the indicators derived for monitoring purposes. First, a unified framework for the computed order tracking method is presented, and then a model linking the statistics of the random jitter to the statistics of the waveform extracted through synchronous averaging in angle domain is developed. The theoretical model connects the random jitter distribution, the number of averaged periods and the ratio of the period of interest to the reference trigger period, to the distribution of the amplitudes of the synchronous frequency components in the synchronously averaged signal. Approximate analytical solutions are derived for cases of interest, allowing the prediction of the attenuation bias and variability of the extracted components amplitudes. The model is first verified against numerical simulations in order to assess consistency, and then parametric studies are presented. Experimental validation is performed on both an experimental and an operational data sets involving respectively a helicopter gearbox and a helicopter fleet.

Item URL in elib:https://elib.dlr.de/125263/
Document Type:Article
Title:Impact of pulse time uncertainty on synchronous average: Statistical analysis and relevance to rotating machinery diagnosis
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Camerini, ValerioDepartment of Aerospace Engineering and Astronautics, University of Rome "La Sapienza", 00184 Rome, Italyhttps://orcid.org/0000-0003-1425-3175
Coppotelli, GiulianoDepartment of Aerospace Engineering and Astronautics, University of Rome "La Sapienza", 00184 Rome, Italyhttps://orcid.org/0000-0003-0254-4987
Bendisch, StefanAirbus Helicopters Deutschland, 86609 Donauwörth, GermanyUNSPECIFIED
Kiehn, DanielDLR Institut für Flugsystemtechnik, 38108 Braunschweighttps://orcid.org/0000-0001-7383-0740
Date:15 August 2019
Journal or Publication Title:Mechanical Systems and Signal Processing (MSSP)
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:129
DOI :10.1016/j.ymssp.2019.04.017
Page Range:pp. 308-336
Publisher:Elsevier
ISSN:0888-3270
Status:Published
Keywords:Health Monitoring, Vibration Monitoring, Synchronous Average, Diagnose
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:rotorcraft
DLR - Research area:Aeronautics
DLR - Program:L RR - Rotorcraft Research
DLR - Research theme (Project):L - The Robust Rotorcraft, L - The Smart Rotorcraft
Location: Braunschweig
Institutes and Institutions:Institute of Flight Systems > Flight Dynamics and Simulation
Deposited By: Kiehn, Daniel
Deposited On:14 Jun 2019 16:19
Last Modified:17 Sep 2019 13:33

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