Aeroservoelastic Model Validation And Test Data Analysis Of The F A 18 Active Aeroelastic Wing PDF Download
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Author | : National Aeronautics and Space Administration (NASA) |
Publisher | : Createspace Independent Publishing Platform |
Total Pages | : 36 |
Release | : 2018-06-20 |
Genre | : |
ISBN | : 9781721585212 |
Download Aeroservoelastic Model Validation and Test Data Analysis of the F/a-18 Active Aeroelastic Wing Book in PDF, ePub and Kindle
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
Author | : Stephen B. Cumming |
Publisher | : BiblioGov |
Total Pages | : 54 |
Release | : 2013-07 |
Genre | : |
ISBN | : 9781289239800 |
Download Active Aeroelastic Wing Aerodynamic Model Development and Validation for a Modified F/a-18a Airplane Book in PDF, ePub and Kindle
A new aerodynamic model has been developed and validated for a modified F/A-18A airplane used for the Active Aeroelastic Wing (AAW) research program. The goal of the program was to demonstrate the advantages of using the inherent flexibility of an aircraft to enhance its performance. The research airplane was an F/A-18A with wings modified to reduce stiffness and a new control system to increase control authority. There have been two flight phases. Data gathered from the first flight phase were used to create the new aerodynamic model. A maximum-likelihood output-error parameter estimation technique was used to obtain stability and control derivatives. The derivatives were incorporated into the National Aeronautics and Space Administration F-18 simulation, validated, and used to develop new AAW control laws. The second phase of flights was used to evaluate the handling qualities of the AAW airplane and the control law design process, and to further test the accuracy of the new model. The flight test envelope covered Mach numbers between 0.85 and 1.30 and dynamic pressures from 600 to 1250 pound-force per square foot. The results presented in this report demonstrate that a thorough parameter identification analysis can be used to improve upon models that were developed using other means. This report describes the parameter estimation technique used, details the validation techniques, discusses differences between previously existing F/A-18 models, and presents results from the second phase of research flights.
Author | : National Aeronautics and Space Administration (NASA) |
Publisher | : Createspace Independent Publishing Platform |
Total Pages | : 50 |
Release | : 2018-05-29 |
Genre | : |
ISBN | : 9781720369455 |
Download Active Aeroelastic Wing Aerodynamic Model Development and Validation for a Modified F/A-18a Airplane Book in PDF, ePub and Kindle
A new aerodynamic model has been developed and validated for a modified F/A-18A airplane used for the Active Aeroelastic Wing (AAW) research program. The goal of the program was to demonstrate the advantages of using the inherent flexibility of an aircraft to enhance its performance. The research airplane was an F/A-18A with wings modified to reduce stiffness and a new control system to increase control authority. There have been two flight phases. Data gathered from the first flight phase were used to create the new aerodynamic model. A maximum-likelihood output-error parameter estimation technique was used to obtain stability and control derivatives. The derivatives were incorporated into the National Aeronautics and Space Administration F-18 simulation, validated, and used to develop new AAW control laws. The second phase of flights was used to evaluate the handling qualities of the AAW airplane and the control law design process, and to further test the accuracy of the new model. The flight test envelope covered Mach numbers between 0.85 and 1.30 and dynamic pressures from 600 to 1250 pound-force per square foot. The results presented in this report demonstrate that a thorough parameter identification analysis can be used to improve upon models that were developed using other means. This report describes the parameter estimation technique used, details the validation techniques, discusses differences between previously existing F/A-18 models, and presents results from the second phase of research flights.Cumming, Stephen B. and Diebler, Corey G.Armstrong Flight Research Center; Kennedy Space CenterF-18 AIRCRAFT; AEROELASTIC RESEARCH WINGS; FLIGHT TESTS; AIRCRAFT MODELS; LEADING EDGE FLAPS; CONTROL SURFACES; DEFLECTION; AIRCRAFT MANEUVERS; SIMULATION; PARAMETER IDENTIFICATION; MAXIMUM LIKELIHOOD ESTIMATES; MACH NUMBER
Author | : National Aeronautics and Space Adm Nasa |
Publisher | : Independently Published |
Total Pages | : 36 |
Release | : 2018-09-17 |
Genre | : Science |
ISBN | : 9781723770630 |
Download Twist Model Development and Results from the Active Aeroelastic Wing F/A-18 Aircraft Book in PDF, ePub and Kindle
Understanding the wing twist of the active aeroelastic wing F/A-18 aircraft is a fundamental research objective for the program and offers numerous benefits. In order to clearly understand the wing flexibility characteristics, a model was created to predict real-time wing twist. A reliable twist model allows the prediction of twist for flight simulation, provides insight into aircraft performance uncertainties, and assists with computational fluid dynamic and aeroelastic issues. The left wing of the aircraft was heavily instrumented during the first phase of the active aeroelastic wing program allowing deflection data collection. Traditional data processing steps were taken to reduce flight data, and twist predictions were made using linear regression techniques. The model predictions determined a consistent linear relationship between the measured twist and aircraft parameters, such as surface positions and aircraft state variables. Error in the original model was reduced in some cases by using a dynamic pressure-based assumption and by using neural networks. These techniques produced excellent predictions for flight between the standard test points and accounted for nonlinearities in the data. This report discusses data processing techniques and twist prediction validation, and provides illustrative and quantitative results.Lizotte, Andrew and Allen, Michael J.Armstrong Flight Research CenterAEROELASTICITY; WINGS; FLEXIBILITY; FLIGHT SIMULATION; REAL TIME OPERATION; DYNAMIC PRESSURE; FLIGHT TESTS; ERROR ANALYSIS; DATA PROCESSING; DATA ACQUISITION
Author | : National Aeronautics and Space Adm Nasa |
Publisher | : |
Total Pages | : 70 |
Release | : 2018-11-03 |
Genre | : |
ISBN | : 9781730725524 |
Download Aeroservoelastic Modeling and Validation of a Thrust-Vectoring F/a-18 Aircraft Book in PDF, ePub and Kindle
An F/A-18 aircraft was modified to perform flight research at high angles of attack (AOA) using thrust vectoring and advanced control law concepts for agility and performance enhancement and to provide a testbed for the computational fluid dynamics community. Aeroservoelastic (ASE) characteristics had changed considerably from the baseline F/A-18 aircraft because of structural and flight control system amendments, so analyses and flight tests were performed to verify structural stability at high AOA. Detailed actuator models that consider the physical, electrical, and mechanical elements of actuation and its installation on the airframe were employed in the analysis to accurately model the coupled dynamics of the airframe, actuators, and control surfaces. This report describes the ASE modeling procedure, ground test validation, flight test clearance, and test data analysis for the reconfigured F/A-18 aircraft. Multivariable ASE stability margins are calculated from flight data and compared to analytical margins. Because this thrust-vectoring configuration uses exhaust vanes to vector the thrust, the modeling issues are nearly identical for modem multi-axis nozzle configurations. This report correlates analysis results with flight test data and makes observations concerning the application of the linear predictions to thrust-vectoring and high-AOA flight. Brenner, Martin J. Armstrong Flight Research Center...
Author | : |
Publisher | : |
Total Pages | : 20 |
Release | : 2002 |
Genre | : Airplanes |
ISBN | : |
Download Strain Gage Loads Calibration Testing of the Active Aeroelastic Wing F/A-18 Aircraft Book in PDF, ePub and Kindle
This report describes strain-gage calibration loading through the application of known loads of the Active Aeroelastic Wing F/A-18 airplane. The primary goal of this test is to produce a database suitable for deriving load equations for left and right wing root and fold shear; bending moment; torque; and all eight wing control-surface hinge moments. A secondary goal is to produce a database of wing deflections mesured by string potentiometers and the onboard flight deflection measurement system. Another goal is to produce strain-gage data through both the laboratory data acquisition system and the onboard aircraft data system as a check of the aircraft system. Thirty-two hydraulic jacks have applied loads through whiffletrees to 104 tension-compression load pads bonded to the lower wing surfaces. The load pads covered approximately 60 percent of the lower wing surface.
Author | : Andrew Lizotte |
Publisher | : BiblioGov |
Total Pages | : 38 |
Release | : 2013-06 |
Genre | : |
ISBN | : 9781289148164 |
Download Twist Model Development and Results from the Active Aeroelastic Wing F/a-18 Aircraft Book in PDF, ePub and Kindle
Understanding the wing twist of the active aeroelastic wing F/A-18 aircraft is a fundamental research objective for the program and offers numerous benefits. In order to clearly understand the wing flexibility characteristics, a model was created to predict real-time wing twist. A reliable twist model allows the prediction of twist for flight simulation, provides insight into aircraft performance uncertainties, and assists with computational fluid dynamic and aeroelastic issues. The left wing of the aircraft was heavily instrumented during the first phase of the active aeroelastic wing program allowing deflection data collection. Traditional data processing steps were taken to reduce flight data, and twist predictions were made using linear regression techniques. The model predictions determined a consistent linear relationship between the measured twist and aircraft parameters, such as surface positions and aircraft state variables. Error in the original model was reduced in some cases by using a dynamic pressure-based assumption and by using neural networks. These techniques produced excellent predictions for flight between the standard test points and accounted for nonlinearities in the data. This report discusses data processing techniques and twist prediction validation, and provides illustrative and quantitative results.
Author | : Martin J. Brenner |
Publisher | : |
Total Pages | : 36 |
Release | : 1997 |
Genre | : Aeroelasticity |
ISBN | : |
Download Wavelet Analyses of F/A-18 Aeroelastic and Aeroservoelastic Flight Test Data Book in PDF, ePub and Kindle
Author | : National Aeronautics and Space Adm Nasa |
Publisher | : Independently Published |
Total Pages | : 44 |
Release | : 2018-09-19 |
Genre | : Science |
ISBN | : 9781723841774 |
Download Flight Test of the F/A-18 Active Aeroelastic Wing Airplane Book in PDF, ePub and Kindle
Successful flight-testing of the Active Aeroelastic Wing airplane was completed in March 2005. This program, which started in 1996, was a joint activity sponsored by NASA, Air Force Research Laboratory, and industry contractors. The test program contained two flight test phases conducted in early 2003 and early 2005. During the first phase of flight test, aerodynamic models and load models of the wing control surfaces and wing structure were developed. Design teams built new research control laws for the Active Aeroelastic Wing airplane using these flight-validated models; and throughout the final phase of flight test, these new control laws were demonstrated. The control laws were designed to optimize strategies for moving the wing control surfaces to maximize roll rates in the transonic and supersonic flight regimes. Control surface hinge moments and wing loads were constrained to remain within hydraulic and load limits. This paper describes briefly the flight control system architecture as well as the design approach used by Active Aeroelastic Wing project engineers to develop flight control system gains. Additionally, this paper presents flight test techniques and comparison between flight test results and predictions.Clarke, Robert and Allen, Michael J. and Dibley, Ryan P. and Gera, Joseph and Hodgkinson, JohnArmstrong Flight Research CenterAEROELASTICITY; FLIGHT CONTROL; FLIGHT TESTS; AEROELASTIC RESEARCH WINGS; AIRCRAFT CONTROL; FLIGHT CHARACTERISTICS; AIRCRAFT DESIGN; AERODYNAMIC CHARACTERISTICS; WING OSCILLATIONS
Author | : Corey G. Diebler |
Publisher | : |
Total Pages | : 47 |
Release | : 2005 |
Genre | : |
ISBN | : |
Download Active Aeroelastic Wing Aerodynamic Model Development and Validation for a Modified F/A-18A Airplane Book in PDF, ePub and Kindle