Wavelet-Processed Flight Data for Robust Aeroservoelastic Stability Margins

Waveletanalysisfore lteringandsystem identie cationisusedto improvetheestimationofaeroservoelastic (ASE) stabilitymargins.Computationofrobuststabilitymarginsforstabilityboundarypredictiondependsonuncertainty descriptions derived from the test data for model validation. Nonideal test conditions, data acquisition errors, and signal processing algorithms cause uncertainty descriptions to be intrinsically conservative. The conservatism of the robust stability margins is reduced with parametric and nonparametric time-frequency analysis of e ight data in the model validation process. Nonparametric wavelet processing of data is used to reduce the effects of external disturbances and unmodeled dynamics. Parametric estimates of modal stability are also extracted using the wavelet transform. F-18 High Alpha Research Vehicle ASE e ight test data are used to demonstrate improved robust stability prediction by extension of the stability boundary from within the e ight envelope to conditions sufe cently beyond the actual e ight regime. Stability within the e ight envelope is cone rmed by e ight test. Practical aspects and guidelines for efe ciency of these procedures are presented for on-line implementation.

[1]  Mark J. Shensa,et al.  The discrete wavelet transform: wedding the a trous and Mallat algorithms , 1992, IEEE Trans. Signal Process..

[2]  Joseph W. Pahle,et al.  An Overview of the NASA F-18 High Alpha Research Vehicle , 1996 .

[3]  Duane Mattern,et al.  Multiscale analysis of stall inception and instabilities in an axi-centrifugal turboshaft engine , 1996 .

[4]  Stéphane Mallat,et al.  Matching pursuits with time-frequency dictionaries , 1993, IEEE Trans. Signal Process..

[5]  Massimo Ruzzene,et al.  NATURAL FREQUENCIES AND DAMPINGS IDENTIFICATION USING WAVELET TRANSFORM: APPLICATION TO REAL DATA , 1997 .

[6]  Marty Brenner,et al.  Incorporating Flight Data into a Robust Aeroelastic Model , 1998 .

[7]  Andrew Packard,et al.  The complex structured singular value , 1993, Autom..

[8]  Rick Lind,et al.  Correlation Filtering of Modal Dynamics using the Laplace Wavelet , 1998 .

[9]  M. Atalla,et al.  On using the wavelet transform to update models , 1998 .

[10]  Rick Lind,et al.  A Worst-Case Approach for On-Line Flutter Prediction , 1998 .

[11]  Marty Brenner,et al.  Estimation of Modal Parameters Using a Wavelet-Based Approach , 1997 .

[12]  Marty Brenner,et al.  Robust Flutter Margins of an F/A-18 Aircraft from Aeroelastic Flight Data , 1997 .

[13]  Rick Lind,et al.  Overview of Recent Flight Flutter Testing Research at NASA Dryden , 1997 .

[14]  Mark J. Shensa.  Discrete inverses for nonorthogonal wavelet transforms , 1996, IEEE Trans. Signal Process..

[15]  Joseph W. Pahle,et al.  Research flight-control system development for the F-18 high alpha research vehicle , 1991 .

[16]  S. Mallat.  A wavelet tour of signal processing , 1998 .

[17]  Rick Lind,et al.  Robust Flutter Margin Analysis that Incorporates Flight Data , 1998 .

[18]  Martin J. Brenner,et al.  Aeroservoelastic Modeling and Validation of a Thrust-Vectoring F/A-18 Aircraft , 1996 .

[19]  Dzu K. Le.  Applications of sampling theorems in wavelet spaces to multiresolution visualization and data segmentation , 1995, Optics + Photonics.

[20]  Eric Feron,et al.  Time-Frequency Analysis for Transfer Function Estimation and Application to Flutter Clearance , 1998 .

[21]  Martin J. Brenner.  Wavelet Analyses of F/A-18 Aeroelastic and Aeroservoelastic Flight Test Data , 1997 .

[22]  Xiang-Gen Xia,et al.  System identification using chirp signals and time-variant filters in the joint time-frequency domain , 1997, IEEE Trans. Signal Process..