aerodynamic modeling for the ohio university uav for the quarterly review of the nasa/faa joint...
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Aerodynamic Modeling for the Ohio University UAV
For the Quarterly Review of the NASA/FAA Joint University Program
for Air Transportation Research
Wednesday October 10th, 2001
Presented By: Sean M. CalhounPrincipal Investigator: Dr. Frank Van Graas
Dr. Douglas Lawrence
Avionics Engineering CenterOhio University, Athens
Project Sponsor:FAA
AVIONICS ENGINEERING CENTER AVIONICS ENGINEERING CENTER OHIO UNIVERSITY, ATHENS OHIO UNIVERSITY, ATHENS
AAU V
AVIONICS ENGINEERING CENTER AVIONICS ENGINEERING CENTER OHIO UNIVERSITY, ATHENS OHIO UNIVERSITY, ATHENS
Overview
• Brumby Specifications
• Basic Aerodynamics
• Instrumentation
• Future of the Brumby
AVIONICS ENGINEERING CENTER AVIONICS ENGINEERING CENTER OHIO UNIVERSITY, ATHENS OHIO UNIVERSITY, ATHENS
AVIONICS ENGINEERING CENTER AVIONICS ENGINEERING CENTER OHIO UNIVERSITY, ATHENS OHIO UNIVERSITY, ATHENS
Configuration•Delta wing aircraft
•Wing span (8.27 feet)
•Dual fins
•Fuselage length (6.46 feet)
•Pusher propeller configuration (7.2 hp)
•Fiberglass composite fuselage
•10 channel radio control receiver
AVIONICS ENGINEERING CENTER AVIONICS ENGINEERING CENTER OHIO UNIVERSITY, ATHENS OHIO UNIVERSITY, ATHENS
Performance Specifications• Maximum Speed: >100 knots
• Maximum Endurance: 40 - 60 minutes
• Maximum Payload: <= 17.6 lb
• Payload Area: 2 (300x220x200mm) sections
Nose Cone Section
•BRUMBY
System Configuration
GPS 1 GPS 2 GPS 3
PC 104
Computer
Spread-Spectrum
Transceiver
Remote
Control
Receiver
Servos
•GROUND STATION
GPSLaptop
Computer
Spread-Spectrum
Transceiver
Remote
Control
Transmitter
AVIONICS ENGINEERING CENTER AVIONICS ENGINEERING CENTER OHIO UNIVERSITY, ATHENS OHIO UNIVERSITY, ATHENS
Payload• Current Payload
– PC 104 CPU with Pentium 166 MHz Processor
> 160 MB Solid State Hard Drive
> QNX Operating System
– 3 Canadian Marconi AllStar GPS Receivers
– FreeWave - 900 MHz Spread Spectrum Transceiver
– NiCad Battery Packs
Modeling
Moment of inertia computation:
AVIONICS ENGINEERING CENTER AVIONICS ENGINEERING CENTER OHIO UNIVERSITY, ATHENS OHIO UNIVERSITY, ATHENS
i
xxiii Izym 22
i
yyiii Ixzm 22
i
zziii Iyxm 22
zxi
xziii IIxzm
xyi
yxiii IIxym
yzi
zyiii IIyzm
AVIONICS ENGINEERING CENTER AVIONICS ENGINEERING CENTER OHIO UNIVERSITY, ATHENS OHIO UNIVERSITY, ATHENS
Modeling
Inertia matrix
Symmetry yields:
zzzyzx
yzyyyx
xzxyxx
III
III
III
I
zzxz
yy
xzxx
I0I
0I0
I0I
I
Modeling
Center of gravity computation:
AVIONICS ENGINEERING CENTER AVIONICS ENGINEERING CENTER OHIO UNIVERSITY, ATHENS OHIO UNIVERSITY, ATHENS
ii
iii
cg m
xmX
ii
iii
cg m
ymY
ii
iii
cg m
zmZ
AVIONICS ENGINEERING CENTER AVIONICS ENGINEERING CENTER OHIO UNIVERSITY, ATHENS OHIO UNIVERSITY, ATHENS
Governing Equations• 3 Force Equations
• 3 Moment Equations
m
FsinθgqWrVU x
0
m
Fcosθ sinφgpWrUV y
0
m
Fcosθ cosφgpVqUW z
0
Nclcp)qcr(cp 4321
Mc)r(pcprcq 722
65
Nclcr)qcp(cr 9428
AVIONICS ENGINEERING CENTER AVIONICS ENGINEERING CENTER OHIO UNIVERSITY, ATHENS OHIO UNIVERSITY, ATHENS
Aerodynamic Coefficients (Force and Moment Equations)
• Drag:
• Lift:
• Side force:
• Rolling moment:
• Pitching moment:
• Yawing moment:
DC*S*q D
LC*S*q L
lC*b*S*q l
M C c S q M* * *
YC*S*q Y
N C c S q N* * *
Aerodynamic Forces
L
Y
D
FSF
FS
F
F
F
F
F
F
F
F
F
BW
B
z
y
x
z
y
x
z
y
x
T
T
T
A
A
A
*
*FB
AVIONICS ENGINEERING CENTER AVIONICS ENGINEERING CENTER OHIO UNIVERSITY, ATHENS OHIO UNIVERSITY, ATHENS
Aerodynamic Coefficients
• Symmetric modes.– CD , CL , Cm.
– Angle-of-attack dominates in symmetric equations.
• Asymmetric modes.– CY , Cl , CN.
– Side-slip angle dominates in asymmetric equations.
• Whether 1st order terms suffice depends on amplitude of flight test maneuvers.
AVIONICS ENGINEERING CENTER AVIONICS ENGINEERING CENTER OHIO UNIVERSITY, ATHENS OHIO UNIVERSITY, ATHENS
Aerodynamic Coefficients
)(C)(C)(CC DDDD eeq
q
)(C)(C)(CC eLLLLeq
q
)(C)(C)(CC eMMMMeq
q
)(C)(C)()(C)(CC rYaYYYYYrar
rCp
)(C)(C)()(C)(CC rlalllllrar
rCp
)(C)(C)()(C)(CC rNaNNNNNrar
rCp
AVIONICS ENGINEERING CENTER AVIONICS ENGINEERING CENTER OHIO UNIVERSITY, ATHENS OHIO UNIVERSITY, ATHENS
InstrumentationRequired measurable variables• Specific forces
– Linear Accelerometers (IMU)
• Angular rates– Gyros (IMU)
• Angular accelerations– Time derivatives of rate measurements
• Propeller Thrust
AVIONICS ENGINEERING CENTER AVIONICS ENGINEERING CENTER OHIO UNIVERSITY, ATHENS OHIO UNIVERSITY, ATHENS
InstrumentationRequired measurable variables (continued)• Impact Pressure
– Total pressure minus static pressure (Pitot Tube)
• Airspeed– Pitot Tube and Pressure Transducers
• Flow angles– Vane measurements
• Control surfaces– Servo output
Air Data BoomAir Data Boom
AVIONICS ENGINEERING CENTER AVIONICS ENGINEERING CENTER OHIO UNIVERSITY, ATHENS OHIO UNIVERSITY, ATHENS
AVIONICS ENGINEERING CENTER AVIONICS ENGINEERING CENTER OHIO UNIVERSITY, ATHENS OHIO UNIVERSITY, ATHENS
Air Data Boom
• Required Electronics:– Total and static pressure
• Nylon tubing
• Pressure transducers
• A/D converters
– Angle of attack and sideslip• Potentiometer leads
• A/D converter
AVIONICS ENGINEERING CENTER AVIONICS ENGINEERING CENTER OHIO UNIVERSITY, ATHENS OHIO UNIVERSITY, ATHENS
Measurement of Forces
• Relationship between the specific force measurements to the total aerodynamic and propulsion forces acting on the aircraft:
F = m * f– F: Aerodynamic and Propulsion Forces– f: IMU Output– m: Total Aircraft Mass
AVIONICS ENGINEERING CENTER AVIONICS ENGINEERING CENTER OHIO UNIVERSITY, ATHENS OHIO UNIVERSITY, ATHENS
Measurement of Forces
• Translation of the force sensor data to the aircraft center of gravity:
)q)(prz(z)r)(pqy(y)r)(qx(xff mcgmcg22
mcgxx mcg
)r)(qpx(x)p)(qrz(z)p)(ry(yff mcgmcg22
mcgyy mcg
)p)(rqy(y)q)(rpx(x)q)(pz(zff mcgmcg22
mcgzz mcg
AVIONICS ENGINEERING CENTER AVIONICS ENGINEERING CENTER OHIO UNIVERSITY, ATHENS OHIO UNIVERSITY, ATHENS
Measurement of Forces
• Body to Flow reference frame transformation:
cosβ sinfsinβfcosβ cosαffbodybodybodyflow zyxx
cosβ sinfcosβfsinβ cosαffbodybodybodyflow zyxy
cosfsinαffbodybodyflow zxz
AVIONICS ENGINEERING CENTER AVIONICS ENGINEERING CENTER OHIO UNIVERSITY, ATHENS OHIO UNIVERSITY, ATHENS
Measurement of Moments
• Total moment components:
ppxzyyzzxx ωI)Ir(pq)Iqr(IIp L
rωI)Ir(p)Irp(IIq M ppxz22
zzxxyy
qωI)Ip(qr)Ipq(IIr N ppxzxxyyzz
Future of the Brumby
• Analyze inertia properties (November 2001)• Development and testing of flight data
instrumentation. (January 2002)• Development of analysis software for post-
flight parameter identification. (January 2002)• Flight Test (Spring 2002)• Brumby Model (Summer 2002)
AVIONICS ENGINEERING CENTER AVIONICS ENGINEERING CENTER OHIO UNIVERSITY, ATHENS OHIO UNIVERSITY, ATHENS
References
• Laban, M. (1994). On-Line Aircraft Aerodynamic Model Identification. PhD. Dissertation Delft University of Technology.
• Stevens, B.L., and Lewis, F.L. (1992). Aircraft Control and Simulation. John Wiley & Sons, Inc.