Aeroservoelastic Uncertainty Model Identification From Flight Data Nasa PDF Download

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Aeroservoelastic Model Validation and Test Data Analysis of the F/a-18 Active Aeroelastic Wing

Aeroservoelastic Model Validation and Test Data Analysis of the F/a-18 Active Aeroelastic Wing
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
Total Pages: 36
Release: 2018-06-20
Genre:
ISBN: 9781721585212

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Model validation and flight test data analysis require careful consideration of the effects of uncertainty, noise, and nonlinearity. Uncertainty prevails in the data analysis techniques and results in a composite model uncertainty from unmodeled dynamics, assumptions and mechanics of the estimation procedures, noise, and nonlinearity. A fundamental requirement for reliable and robust model development is an attempt to account for each of these sources of error, in particular, for model validation, robust stability prediction, and flight control system development. This paper is concerned with data processing procedures for uncertainty reduction in model validation for stability estimation and nonlinear identification. F/A-18 Active Aeroelastic Wing (AAW) aircraft data is used to demonstrate signal representation effects on uncertain model development, stability estimation, and nonlinear identification. Data is decomposed using adaptive orthonormal best-basis and wavelet-basis signal decompositions for signal denoising into linear and nonlinear identification algorithms. Nonlinear identification from a wavelet-based Volterra kernel procedure is used to extract nonlinear dynamics from aeroelastic responses, and to assist model development and uncertainty reduction for model validation and stability prediction by removing a class of nonlinearity from the uncertainty. Brenner, Martin J. and Prazenica, Richard J. Armstrong Flight Research Center NASA/TM-2003-212021, H-2526, NAS 1.15:212021


Development of the X-33 Aerodynamic Uncertainty Model

Development of the X-33 Aerodynamic Uncertainty Model
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
Total Pages: 36
Release: 2018-07-02
Genre:
ISBN: 9781722168407

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An aerodynamic uncertainty model for the X-33 single-stage-to-orbit demonstrator aircraft has been developed at NASA Dryden Flight Research Center. The model is based on comparisons of historical flight test estimates to preflight wind-tunnel and analysis code predictions of vehicle aerodynamics documented during six lifting-body aircraft and the Space Shuttle Orbiter flight programs. The lifting-body and Orbiter data were used to define an appropriate uncertainty magnitude in the subsonic and supersonic flight regions, and the Orbiter data were used to extend the database to hypersonic Mach numbers. The uncertainty data consist of increments or percentage variations in the important aerodynamic coefficients and derivatives as a function of Mach number along a nominal trajectory. The uncertainty models will be used to perform linear analysis of the X-33 flight control system and Monte Carlo mission simulation studies. Because the X-33 aerodynamic uncertainty model was developed exclusively using historical data rather than X-33 specific characteristics, the model may be useful for other lifting-body studies. Cobleigh, Brent R. Armstrong Flight Research Center RTOP 242-33-02-00-23...


Identification of Low Order Equivalent System Models from Flight Test Data

Identification of Low Order Equivalent System Models from Flight Test Data
Author: National Aeronautics and Space Adm Nasa
Publisher: Independently Published
Total Pages: 70
Release: 2018-09-20
Genre: Science
ISBN: 9781723851292

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Identification of low order equivalent system dynamic models from flight test data was studied. Inputs were pilot control deflections, and outputs were aircraft responses, so the models characterized the total aircraft response including bare airframe and flight control system. Theoretical investigations were conducted and related to results found in the literature. Low order equivalent system modeling techniques using output error and equation error parameter estimation in the frequency domain were developed and validated on simulation data. It was found that some common difficulties encountered in identifying closed loop low order equivalent system models from flight test data could be overcome using the developed techniques. Implications for data requirements and experiment design were discussed. The developed methods were demonstrated using realistic simulation cases, then applied to closed loop flight test data from the NASA F-18 High Alpha Research Vehicle.Morelli, Eugene A.Langley Research CenterEXPERIMENT DESIGN; DYNAMIC MODELS; SYSTEM IDENTIFICATION; FLIGHT TESTS; DATA PROCESSING; FLIGHT CONTROL; DEFLECTION; AIRCRAFT PERFORMANCE; ERROR ANALYSIS; FLIGHT CHARACTERISTICS; FEEDBACK CONTROL


The Aeronautical Journal

The Aeronautical Journal
Author:
Publisher:
Total Pages: 820
Release: 2003
Genre: Aeronautics
ISBN:

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