Aeroelastic Model Structure Computation for Envelope Expansion

Kukreja, Sunil L. (2007) Aeroelastic Model Structure Computation for Envelope Expansion. Technical Report NASA/TM-2007-214623, Research and Engineering, NASA Dryden Flight Research Center.

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Abstract

Structure detection is a procedure for selecting a subset of candidate terms, from a full model description, that best describes the observed output. This is a necessary procedure to compute an efficient system description which may afford greater insight into the functionality of the system or a simpler controller design. Structure computation as a tool for black-box modeling may be of critical importance in the development of robust, parsimonious models for the flight-test community. Moreover, this approach may lead to efficient strategies for rapid envelope expansion that may save significant development time and costs. In this study, a least absolute shrinkage and selection operator (LASSO) technique is investigated for computing efficient model descriptions of non-linear aeroelastic systems. The LASSO minimises the residual sum of squares with the addition of an l subscript 1 penalty term on the parameter vector of the traditional l subscript 2 minimisation problem. Its use for structure detection is a natural extension of this constrained minimisation approach to pseudolinear regression problems which produces some model parameters that are exactly zero and, therefore, yields a parsimonious system description. Applicability of this technique for model structure computation for the F/A-18 (McDonnell Douglas, now The Boeing Company, Chicago, Illinois) Active Aeroelastic Wing project using flight test data is shown for several flight conditions (Mach numbers) by identifying a parsimonious system description with a high percent fit for cross-validated data.

EPrint Type:	NASA Technical Memorandum
Keywords:	Aeroservoelasticity, F/A-18 aircraft, Least absolute shrinkage and selection operator (LASSO), Linear system identification, Nonlinear system identification, Structure detection
Subjects:	(59 - 67) Mathematical and Computer Sciences: (66) Systems Analysis (01 - 09) Aeronautics: (02) Aerodynamics (59 - 67) Mathematical and Computer Sciences: (64) Numerical Analysis (01 - 09) Aeronautics: (08) Aircraft Stability And Control Aircraft/Project: F-18 AAW
ID Code:	1681
Deposited On:	13 July 2007
Additional Information:	17 pages. Also presented as AIAA-2007-2317 at the AIAA/ASME/ASCE/AHS/ASC 48th Structures, Structural Dynamics, and Materials Conference, Honolulu, Hawaii, April 23–26, 2007. Kukreja, NASA Dryden Flight Research Center.