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THE INFLUENCE OF PERIOD VARIATION ON TIME–FREQUENCY ANALYSIS OF THE WESTLAND HELICOPTER DATA

✍ Scribed by SOON-SENG LAU; PETER J. SHERMAN

Publisher
Elsevier Science
Year
2000
Tongue
English
Weight
287 KB
Volume
14
Category
Article
ISSN
0888-3270

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✦ Synopsis

In this work, we address the in#uence of period variation on the Westland CH-46E helicopter vibration data. The estimation of the time-varying shaft speed by using a newly developed constrained AR(2) estimator and the well-known EKF estimator will be discussed. The in#uence that the period variation captured by these two estimators have on the periodic time}frequency analysis will be illustrated via numerical simulation. This simulation clearly illustrates a potential spectral smearing if the period variation is not properly accommodated. A data resampling scheme will then be proposed to eliminate the spectral smearing e!ect. The potential of this scheme will be demonstrated via the analysis of the helicopter vibration data.

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