High accuracy in flight wing
Presented by H.W. Jentink National Aerospace Laboratory NLR Amsterdam, The Netherlands Contributions from NLR, DLR and Airbus France Aerospace Testing, Hamburg, 19 May 2010
Nationaal Lucht- en Ruimtevaartlaboratorium – National Aerospace Laboratory NLR
Contents
Introduction of the project andobjectives Measurement requirements Equipment and measurement setup Post-processing and analysis approach Results Metro tests static wing deflection wing dynamics aileron deflection, rotation, gap Airbus A380 test campaign Conclusion on in-flight DIC performances
2
AIM – EC 6th Frame Work Programme
AIM: Advanced In-flight Measurement techniques Introduction of innovative optical measurementtechniques in flight testing Digital Image Correlation (DIC) technique for wing deflection measurement as alternative to proven techniques photogrammetry accelerometer strain gauges Requirements and objectives defined by European aircraft manufacturing industry: Airbus (Fr) Piaggio (It) Eurocopter (Fr+Dl) EVEKTOR (Cz)
3
Principles of Digital Image Correlation (DIC) technique
4Stereoscopic Approach
5
Requirements for in-flight wing deflection at Metro aircraft
Wing heave: accuracy at least 0.5 mm feasibility to measure relationship wing heave and normal load Wing torsion: accuracy at least 0.1° Wing vibration modes: frequencies up to 8 Hz Measurement feasibility for aileron: rotation gap with main wing Assessment of degradation from: standard aircraft Plexiglas windowinstead of optical glass poor locations, e.g. fuselage
6
IPCT on one of NLR’s research aircraft: Fairchild Metro II
7
Camera positions on Metro aircraft
Measurement area
8
Rigid camera / IRS frame
9
Camera timing, triggering and synchronization
PC User Interface System Control GPS Antenna
Ethernet HUB Camera A Jai TM-1327GE Laptop A GigE FAST ethernet Timed datastorage + camera control
Datum GPS TCG Common Time Reference System
IRIG-B
Synchronisation & Time Server
Accurately Timed Frame triggering
Camera B Jai TM-1327GE Laptop B GigE FAST ethernet Timed data storage + camera control To analog instrumentation + analog video System
10
Aircraft Installation of Camera Frame
11
IRS installation at the Camera frame
12
3-axisaccelerometer installed at wing tip
13
Dot generation software tool
14
Newly developed at NLR: complete 3D approach for Visual Geometrical Coordinate System transformation Visual grid (Xopt,Yopt) in pixel coordinates Geometrical coordinate system (X,Y,Z) aligned with flat (reference) wing
Optical grid on main wing Geometrical grid on main wing
Y Z X
15
Hangar activitiescalibrations & verifications – curved Plexiglas effects – reference grid – deflection (micrometer) – vibration (vs. accelerometer, IRS)
16
Hangar test: Verification DIC vs. Micrometer
micrometer
Fuel re-fill
17
Hangar: DIC verification vs. micrometer
Micrometer 0-300 liter fuel: 3.55 mm wing deflection at ref point DIC using PivView: DIC using Matlab: extrapolation to ref. point:3.47 mm extrapolation to ref. point: 3.46 mm
Only 0.08 mm: 2% rel. error (due to small deflection amplitude)
With full 3D approach excellent agreement with micrometer measurement obtained!
18
... and then: the in-flight DIC measurements ....
19
In-flight DIC images: wing frames at 0g and 2 g
20
Vertical displacements of wing surface at 0 g and 2 g relative to 1 g(straight level flight)
21
Desired End Result: Determined coefficients(n) of Wing Deflection Model by least square fitting of results obtained at various loads Wing Deflection Model: z = c0 + cXX + cYY + cXYXY + cX2X2 + εz
where: X coordinate parallel to fuselage centre line (X=0 wing’s main beam) Y coordinate towards wing tip (Y=0 at tip, end of main beam) z local geometrical displacement...
Regístrate para leer el documento completo.