Loads Model Development and Analysis for the F/A-18 Active Aeroelastic Wing Airplane

Allen, Michael J.; Lizotte, Andrew; Dibley, Ryan P.; Clarke, R.J.

doi:10.2514/6.2005-6313

Cited by 7 publications

(4 citation statements)

References 6 publications

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“…Results are presented for models of four wing loads and four control surface hinge moments. However, in [3] it is mentioned that the method based on neural networks was abandoned, because the high extrapolation required could not be easily analysed for uncertainty.…”

Section: Methods Descriptionsmentioning

confidence: 97%

Comparison of real-time flight loads estimation methods

2014

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Nowadays flight load exceedance monitoring is an important task to both: the aircraft manufacturer as well as the operator. The estimation of flight loads is required in several phases during development and operation of an aircraft. The requirements are usually different, for e.g. calculation of design loads for certification and operational loads monitoring of stress and fatigue. The ability to determine aircraft operational loads (more) precisely may reduce the time in maintenance. Being able to detect critical load exceedance events during flight or in a post-process is also an enabler for e.g. loads/fatigue monitoring at operator level. In this paper, a novel system identification method named local model networks is applied to the field of flight loads estimation and compared to approaches based on artificial neural networks as found in the literature. The presented approach tries to overcome some limitations with respect to model creation, robustness, interand extrapolation.

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Section: Methods Descriptionsmentioning

confidence: 97%

Comparison of real-time flight loads estimation methods

2014

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“…A similar system was employed by the Active Aeroelastic Wing study on a modified F/A-18. 12 More recently, a JAXA Beechcraft Queen Air low wing research aircraft was instrumented with a stereovision rig. 13 The setup included two high resolution CCD cameras looking out through its cabin windows, capturing fiducial markers painted on the wing.…”

Section: Figure 1 Um X-hale 6-meters Aeroelastic Test Vehicle Modelmentioning

confidence: 99%

In-Flight Wing Deformation Measurement System for Small Unmanned Aerial Vehicles

Pang

Cesnik

Atkins

2014

55th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

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This paper presents a new method to measure wing deflections in flight for small UAVs. It employs a pair of high resolution stereo cameras and LED wing markers, as well as a small form factor computer for control and storage. Post-processing of all the data is done off-line. Accuracy benchmark tests are conducted. Finally, theoretical discussion of wing shape reconstruction is presented. The method employs numerical optimization by minimizing the difference between numerical geometrically nonlinear slender beam equations and observed markers points with associated uncertainties.Nomenclature c x ,c y = principal focal point C = circularity d = disparity e = error metric f x ,f y = focal length (in pixels) F = focal length F i ,M i = design variables (point forces and moments in UM/NAST) J = cost functional k 1 ,k 2 ,k 3 = radial distortion parameters k = nodal points where point forces and moments are applied N = number of marker points p 1 ,p 2 = tangential distortion parameter p i = beam deflection computed by UM/NAST q i = measured beam deflection Q = reprojection matrix r = radial distance R = rotation matrix t = translational vector T x = x component of rotation matrix x,y = image coordinates (distorted) x c ,y c = image coordinates (pin hole model) X,Y,Z = physical coordinates X cb,i = known checkerboard coordinates σ i = error weight

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“…In 1996, the Air Force Research Laboratory and NASA initiated the Active Aeroelastic Wing (AAW) project (later assigned the designation of "X-53") to investigate the use of wing twist for roll control. The AAW concept was tested on a modified F/A-18 supersonic fighter aircraft during the spring of 2005 [12]. The AAW program had wings modified for reduced torsional stress that required the development of tools to concurrently integrate control and structural design.…”

Section: Active Aeroelastic Wing (Aaw) Programmentioning

confidence: 99%

Integration of Aeroservoelastic Properties into the NASA Dryden F/A-18 Simulator Using Flight Data from the Active Aeroelastic Wing Program

Chin

Brenner

Pickett

2011

AIAA Atmospheric Flight Mechanics Conference

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Aircraft structures have varying stiffness levels making them flexible. Consequently, this elastic property becomes increasingly important at high speeds affecting the flight dynamics of the aircraft. In high speed aircraft such as the F/A-18, elastic structural properties must be accounted for to ensure confidence in predicted flight dynamics in order to avoid adverse aeroelastic phenomena throughout flight. Data from the F/A-18 Active Aeroelastic Wing (AAW) program was used to create aeroservoelastic (ASE) models at varying flight conditions. The discretized ASE models were integrated into the NASA Dryden F/A-18 simulator in parallel with the traditional 6-DOF (degrees-of-freedom) flight dynamics calculations to ensure minimal disruption to the existing operating framework of the simulator. An interpolation scheme was used to construct ASE models within the known flight condition models. Data was processed through the state-space ASE models to compute the elastic effects during flight. Total flight dynamics from the simulation were analyzed and showed expected behavior for the combined elastic and rigid-body components in flight.

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Loads Model Development and Analysis for the F/A-18 Active Aeroelastic Wing Airplane

Cited by 7 publications

References 6 publications

Comparison of real-time flight loads estimation methods

Comparison of real-time flight loads estimation methods

In-Flight Wing Deformation Measurement System for Small Unmanned Aerial Vehicles

Integration of Aeroservoelastic Properties into the NASA Dryden F/A-18 Simulator Using Flight Data from the Active Aeroelastic Wing Program

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