DEATH BY A THOUSAND CUTS: MICRO-AIR VEHICLES (MAV) IN THE SERVICE OF AIR FORCE MISSIONS
Micro Air Vehicle (MAV) Propulsion
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Transcript of Micro Air Vehicle (MAV) Propulsion
Micro Air Vehicle (MAV) Propulsion
Project P6002Project P6002Preliminary Design Presentation
November 2005November 2005
Zach Kilcer, Bill Strong, Joe Olles, Sean Dittrich, Brian Stumper, Doug BrownZach Kilcer, Bill Strong, Joe Olles, Sean Dittrich, Brian Stumper, Doug Brown
2
Team Members
Names from left to right: Bill Strong, Douglas Brown, Brian Stumper, Zach Kilcer, Sean Dittrich, Joe Olles, and Dr. Kozak
3
MAV Motivation
• Effectively retrieve GPS data video feed.
• DARPA funded effort for use by American Soldiers and Intelligence Agents by 2010.
• Wide range private sector applications
• Annual international design competition
4
Introduction: MAV at RIT• Offshoot of the RIT Aero Design Team• Fourth year MAV Team at RIT• RIT annually attends International Competitions• Current MAV Senior Design effort in support of MAV
Team • Unique design project due to limited information and
research on small scale vehicles
5
Mission Statement
Develop an efficient, light weight and cost effective propulsion system for the RIT
MAV club.
6
Overview
• Needs Assessment• Requirements• Concept Generation• Feasibility Testing• Analytical Analysis• Electronic System Optimization• Design of Baseline System• Electronic System• Senior Design II Specifications• Future Plans
7
Needs Assessment
• Performance Goals– The thrust-to-weight ratio of the propulsion system shall exceed
the thrust-to-weight ratio of the MAV 05’ design.– The power system shall be designed to optimize efficiency and
weight requirements for the propulsion system.
• Design Goals– The deliverable shall consist of more than one design.– The propulsion system shall be durable enough to withstand a
crash landing.– The propulsion system shall be easily integrated into future
airframes and anticipated electronic components.
8
Brainstorming
Jet Turbine EngineDucted Propeller
Variable Pitch PropellerInternal Combustion
Engine with a Propeller Shrouded Propeller
9
Concept Evaluation: Pugh Chart
Evaluation Chart
Motor / Prop Jet turbineInternal
combustion engine
Ducted PropShrouded
propVariable
Pitch Prop
Cost 0 - 0 - 0 -
weight 0 - - - - -
thrust 0 + + + + +
size 0 - - 0 0 0
durability 0 0 0 + + 0
drag 0 - - - 0 +
number of parts
0 - 0 - - -
ease of integration
0 - - + 0 -
Complexity of Design
0 - - 0 0 -
Total + 0 1 1 3 2 2
Total - 0 7 5 4 2 5
Sum 0 -6 -4 -1 0 -3
10
Propeller and Motor• Easy design to produce with the teams limited resources• Careful selection of a motor and propeller combination
will increase performance
11
Shrouded Propeller
• Increase thrust and efficiency
• Reduce propeller tip vortices
• Increase durability of propulsion system
12
Ducted Propeller• Reduce propeller tip vortices • Significantly increase thrust
– acts as a nozzle, raising the exit velocity
• Increase durability of propulsion system
• Equation for Open and Ducted Props• Significantly increase thrust
• Reduce propeller tip vortices
• Increase durability of propulsion system
13
Propeller and MotorAnalytic Proof of Concept
• Blade Element theory:– The airflow is treated as a
2D flow with no mutual interaction between blade sections.
– The blade is composed of independent elements
– The differential element of fixed chord, is located at a specific radius-chord changes with respect to radius
14
Velocity ConsiderationsVelocity Analysis
0.0000
20.0000
40.0000
60.0000
80.0000
100.0000
120.0000
0.000 0.500 1.000 1.500 2.000 2.500
Radius (in)
Ex
pe
rie
nc
ed
Ve
loc
ity
(ft
/s)
15
Reynolds Number Considerations
Reynolds Number Analysis
0
20000
40000
60000
80000
100000
120000
140000
160000
180000
0 0.5 1 1.5 2 2.5
Radius (in)
Re
yn
old
s N
um
be
r
16
Mach Number ConsiderationsMach Number Analysis
0
0.002
0.004
0.006
0.008
0.01
0.012
0.014
0.016
0.018
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
Radius (in)
Ma
ch
Nu
mb
er
17
Propeller and Motor Analytic Proof of Concept
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
r/R [Normalized Radius]
Tip
-Lo
ss
Fa
cto
r
)(11 UVAVTh exit • Thrust analysis based on Momentum theory
18
Shrouded PropellerAnalytic Proof of Concept
• Thrust analysis based on Momentum theory
• Reynolds number calculation
• Coefficient of Drag for laminar flow over a flat plate
• Drag Force
)(11 UVAVTh exit
LU
LRe
eLRDC 33.1
plateDD AUCF 221
19
Ducted PropellerAnalytic Proof of Concept
])(43[1
241
ATh
ThPw UU
• Power to Thrust ratio analysis based on Momentum theory
• Duct Drag Equation
31
12
)( 4
APwhT
)(22
21 LRV
FDD
ioC
2222 LD
LLb
SD CkCkC
20
Fabricated Components
There are unique performance requirements for each component to be fabricated.
• Shrouds
• Ducts
• Motor Mounts
• Propellers
21
Materials
Multiple materials available for component fabrication. Each has unique characteristics.
• Composites
• Polymers
• Polymer Foam
22
Materials Processing
• Unique processing methods for each material
• Each method has characteristic advantages and disadvantages
• Processing Procedures:– Hot Wiring– Lay-up Molding– Injection Molding– Rapid Prototyping
23
Static Test Setup
• Used to determine the feasibility of the three (3) different prop designs
• Measurements Included:– Thrust– Motor Speed– Inlet / Exit Velocity– Temperature– Air Pressure
24
Static Test Results
Thrust vs. Motor Current
10.00
12.00
14.00
16.00
18.00
20.00
22.00
24.00
0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1
Motor Current (Amps)
Th
rus
t (g
)
Baseline PropShrouded Prop (Bell Mouth)Ducted Prop (Concave)Ducted Prop (Convex)Linear (Baseline Prop)Linear (Shrouded Prop (Bell Mouth))Linear (Ducted Prop (Concave))Linear (Ducted Prop (Convex))
25
Test ResultsAt 2800RPM
Calculated Thrust (g) Measured Thrust (g) % Error
Baseline Prop 1 19.99 22.89 14.49
Baseline Prop 2 18.97 18.82 0.80
Calculated Thrust (g) Measured Thrust (g) % Error Drag Force (g)
Shroud 1 26.62 18.31 31.22 0.35
Shroud 2 Bell-Mouth 19.40 20.35 4.88 0.217
Calculated Thrust (g) Measured Thrust (g) % Error Drag Force (g)
Concave Duct 23.21 23.81 2.57 29.42
Convex Duct 1 23.08 19.30 16.36 19.534
Convex Duct 2 20.11 17.07 15.10 13.59
26
Design Constraints
Constraint Minimum Value Maximum Value
Thrust 60g 150g
Weight 60g 150g
Efficiency (Thrust / Weight) 1.0 1.75
Auxiliary Power 300mA 500mA
Range 600m 3200m
Battery Lifetime 15min 30min
27
Historical Motor/Prop Performance Parameters
Motor PropellerNo. LiPoly
CellsThrust
(g)
Motor Current
(A)
Motor Weight
(g)
Max Current
(A)
Battery Weight
(g)
Propulsion Weight (g)
Flight Time (min)
Thrust-to-Weight Ratio
Firefly GWS 4350 2 26 0.26 14.00 0.76 5.6 69.61 9.01 0.37
Firefly GWS 4540 2 30 0.47 14.00 0.97 8.3 72.30 11.06 0.41
Firefly GWS 5030 2 36 0.42 14.00 0.92 7.7 71.66 10.66 0.50
Firefly GWS6030 2 44 0.54 14.00 1.04 9.2 73.19 11.56 0.60
Firefly GWS 7035 2 60 0.82 14.00 1.32 12.8 76.77 13.03 0.78
Firefly GWS 4350 3 56 0.69 14.00 1.19 16.7 80.66 12.43 0.69
Firefly GWS 4540 3 64 0.86 14.00 1.36 19.9 83.92 13.19 0.76
Firefly GWS 5030 3 74 0.79 14.00 1.29 18.6 82.58 12.90 0.90
Firefly GWS6030 3 86 0.99 14.00 1.49 22.4 86.41 13.65 1.00
Mighty Micro GWS 6030 2 246 5.60 32.00 6.10 73.9 155.86 17.30 1.58
Mighty Micro 5.5 X 4 MAS 2 212 6.40 32.00 6.90 84.1 166.08 17.44 1.28
Mighty Micro 6 X 4 APCE 2 237 7.20 32.00 7.70 94.3 176.31 17.54 1.34
Mighty Micro EP 7035 GWS 2 286 7.40 32.00 7.90 96.9 178.86 17.57 1.60
Mighty Micro 7 X 4 APCE 2 277 9.10 32.00 9.60 118.6 200.59 17.73 1.38
Mighty Micro 7 X 5 APCE 2 266 9.70 32.00 10.20 126.3 208.26 17.77 1.28
Mighty Micro EP 6030 GWS 3 311 6.90 32.00 7.40 135.7 217.71 17.51 1.43
Mighty Micro 6 X 4 APCE 3 308 10.40 32.00 10.90 202.8 284.80 17.82 1.08
Mighty Micro EP 7035 GWS 3 401 10.60 32.00 11.10 206.6 288.64 17.83 1.39
Mighty Midget U-80 1 29 1.30 3.70 1.80 9.5 63.15 14.48 0.46
Mighty Midget GWS 3x2 prop 1 29 1.30 3.70 1.80 9.5 63.15 14.48 0.46
Mighty Midget GWS 4x2.5 1 37 1.90 3.70 2.40 13.3 66.99 15.48 0.55
28
Motor/Prop Feasibility Analysis
FactorsImportance
[1]
Firefly w/ GWS6030 Mighty Micro w/GWS 6030
ScoreWeighted
ScoreScore[2]
Weighted Score
Thrust 8 0 0 + 8
Weight 7 + 7 - -7
Efficiency 6 0 0 + 6
Size 5 + 5 - -5
Cost 4 + 4 - -4
Battery Lifetime
3 - -3 + 3
Flight Range 2 0 0 0 0
Auxiliary Power
1 0 0 0 0
Total Score 13 1
[1] Definition of Importance: “1” = Least important, “8” = most important.[2] Definition of Score: “-“ = Below initial spec, “0” = Meets initial spec, “+” = Exceeds initial spec [1] Definition of Importance: “1” = Least important, “8” = most important.[2] Definition of Score: “-“ = Below initial spec, “0” = Meets initial spec, “+” = Exceeds initial spec
29
Baseline System Performance Specifications are derived using a Firefly 799 coreless
motor with a GWS6030 propeller.
Factor Anticipated Performance
Thrust 86g
Weight 81g
Thrust-to-weight ratio 1.05
Size (max dimension) 6”
Battery Life (Baseline with no camera/servos) 17 min
Battery Life (Includes two (2) servos) 15 min
Battery Life (Includes two servos and camera) 12 min
Flight Range 1 mile
Number of Channels 5
Auxiliary Power 5.0W ([email protected])
Estimated Surplus Power 0.50W ([email protected])
Motor / Prop Baseline Specifications
30
Wiring Diagram
p/n: Firefly 799
Coreless MotorSpeed
Controllerp/n: Astro 200
LiPoly Battery(3.7V @ 1.5A)
p/n: LP300
LiPoly Battery(3.7V @ 1.5A)
p/n: LP300
LiPoly Battery(3.7V @ 1.5A)
p/n: LP300
Power Source (11.1V @ 1.5A)
Micro 2R Polarized Connectors p/n: 1222
RF Receiverp/n: 805FM72V2
Throttle Channel (Typically 3)
Servo Connector
Ch 46
Crystal Oscillatorp/n: RXQTM72-(41-50)
White = signalBlack = groundRed = Power (+5V)
Propellerp/n: GWS6030 or Equivalent
31
Power Budget
Component
Part Number
DescriptionVoltage
(V)Current
(A)
Power Source
LP300 (x3)LiPoly 300mAh
11.1 1.500
Speed controller
Astro 200Coreless speed controller
5.0 0.025
RF receiver FMA M5v2Sub-micro receiver
5.0 0.025
Electric motor
799Firefly coreless motor
11.1 0.980
Servo motors
BlueArrow 3.6
Light weight servo motors (x2)
5.0 0.200
Video camera
Core 5-2450mW Video Transmitter
10.0 0.100
Video transmitter
CX161Panasonic Camera
5.0 0.120
Power Surplus
0.050
Power Distribution Breakdown
32
Weight BudgetComponent Part Number Description
Weight (g)
Propeller GWS 60306” x 3” direct drive propeller
2
Speed controller
Astro 200Coreless speed controller
3
RF receiver FMA M5v2Sub-micro receiver (1-mile range) 8
Power source
LP300 (x3)Platinum polymer 300mAh battery
20
Electric motor
799Firefly coreless motor 14
Motor mount
MAV ClubPropulsion system Motor mount
30
Connectors GenericBattery / motor connectors and corresponding wires
5
Total Weight 82
Weight Budget Breakdown
33
Bill of Materials
Item Qty Description Manufacturer Distributor Part NumberUnitCost Cost
1 9 LiPoly Battery (3.7V/1.5A/300mAh) Platinum Polymer http://www.batteriesamerica.com LP300 $7.95 $71.55
3 2 Coreless Motor Speed Controller (3A Max) Astro Flight http://www.astroflight.com Astro 200 $19.95 $39.90
4 2 Firefly Coreless Planetary Motor Astro Flight http://www.astroflight.com 799 $49.95 $99.90
5 2 M5v2 Sub Micro Receiver FMA Direct http://www.fmadirect.com 805FM72V2 $39.95 $79.90
- -
Options: Fut/Hitec Type
"" http://www.fmadirect.com 805FM72V2 - -(See item 5)
6 1 72 MHz Crystals (Channel 46) FMA Direct http://www.fmadirect.com RXQTM72-(41-50) $9.95 $9.95
7 10 4 x 2.5 Direct Drive Electric Propeller GWS http://www.balsapr.com EP-4025 $0.89 $8.90
8 10 6 x 3 Direct Drive Propeller GWS http://www.balsapr.com EP-6030 $1.12 $11.20
9 5 Two-Pin Male JST Connector GWS http://www.balsapr.com W22/2PJST/30 $1.50 $7.50
10 5 Two-Pin Female JST Connector GWS http://www.balsapr.com W22FM/2PJST/30 $1.50 $7.50
11 5 Black Two-Pin M3 Motor Connector Generic http://www.balsapr.com *Generic See Desc $1.90 $9.50
12 5 Black Two-Pin C3 Speed Controller Connector Generic http://www.balsapr.com *Generic See Desc $1.95 $9.75
13 5 5.7 oz 1st ‘Quality’ Plain Weave Carbon Fiber US Composites http://www.shopmaninc.com FG-CARB5750 $31.50/yd $157.50
14 1 2 Gallon Epoxy Resin & 1 Gallon Hardener Us Composites http://www.shopmaninc.com EPOX-635314 $94.50 $94.50
Total $607.55
34
Senior II Design Specifications• Performance Specifications
– The thrust-to-weight ratio of the propulsion system shall meet or exceed a value of 1.00
– The weight of the motor mount (or shroud) shall not exceed 30.0 grams. – The propulsion system shall be designed to endure a 15 minute flight.– The propulsion system shall have a minimum flight range of 600 meters.
• Design Objectives– The propulsion system shall be durable enough to withstand a crash
landing.– The propulsion system shall be easily integrated into future airframes
and anticipated electronic components.– The propulsion system shall be designed using light weight composites
and polymer materials.– The propulsion system shall be compatible with the airframe designed
by the MAV 05’ winter/spring senior design I team.– The final products delivered to the MAV club shall consist of multiple
(more than one) design.
35
Senior II Design Specifications (cont)• Power source
– The MAV shall be powered using lithium polymer batteries.– The battery weight shall not exceed 20 grams.– The batteries shall supply 1.50 amps of current at 11.1 volts– The battery lifetime shall meet or exceed 15 minutes.
• Control System– The range of the RF receiver shall meet or exceed 600 meters.– The RF receiver shall contain a minimum of 4 channels.
• Electronic Motor– The electric motor shall consist of a firefly coreless (or equivalent)
motor.– The electric motor shall maintain thermal stability during flight.
• Future Electronics– The electronic system shall provide an additional 400mA of auxiliary
power for two (2) servo motors, a video camera, and a video transmitter.
36
Summary
• Five (5) different propeller designs were investigated.• Feasibility analysis eliminated two (2) designs.• Analytical analysis was performed• Static testing validated the analytical results.• Specifications were developed for the propulsion system.• A baseline system was designed with an optimal
electronic system.• A plan was generated to optimize the propulsion system
for future MAV needs.• Composites and propeller design will be investigated for
future use.
37
Phase II Work Plan1. Implement baseline motor/prop design2. Baseline motor/prop static testing
a. Run static testb. Organize/interpret resultsc. Evaluate motor / prop combinations
3. SDII test fabricationa. Develop new ducts/shrouds/propellers
i. Molds (machined/rapid prototyped)ii. Components (injection molded/rapid prototyped/composite lay-up)
b. Develop dynamic test fixture c. Dynamic Test Setup
i. Setup the necessary equipmentii. Organize collected dataiii. Calibrate the test equipment
d. Develop dynamic test procedurei. Document the testing processii. Identify control variablesiii. Develop a test matrix
4. Static / dynamic testinga. Run static and dynamic testsb. Record / organize resultsc. Interpret resultsd. Evaluate designe. Propose new designs to fabricate
5. Implement into airframea. Present findings to winter/spring teamb. Work to implement design
i. Mechanical considerationsii. Electrical considerations
38
Future Work• Obtain additional design constraints from the airframe
senior design team (Winter/Spring)• Implement the baseline motor / prop system• Optimize efficiency by investigating different
configurations for:• Dimension• Profile• Weight• Component Materials
• Deliver final designs to the MAV club.
39
Questions?
40
Backup Slides
41
Shrouded PropellerDuct Fabrication
42
Inverse Methods
• Two Inverse methods to chose from:– First, based on the Prandtl-Betz Theory
• Starts with an optimal circulation distribution and relates chord and angle of attack for the best design case.
– Second, computes profiles from velocity distributions
• Based on propeller airfoil requirements• Tip requirements determined by compressible flow,
hub determined by viscous effects.
43
The Velocity Triangle
• The propeller blade does not only feel the effects of the upstream velocity, but also the velocity of rotation.
• This is accounted for in the velocity triangle where actual velocity seen is the square root of upstream velocity squared plus tangential velocity squared.
44
Reynolds Number Considerations
• As the radius is increased, the Reynolds Number curve grows steeper
• Moving outward from the hub, Reynolds Number increases linearly
45
Other Possible Features
• Custom Propeller Blades– Would provide superior efficiency, weight, and
durability– Requires custom built molds
Electronic Subsystem
Primary Electronics
• RF Transmitter• RF Receiver• Battery• Electric Motor• Speed Controller
Future Electronics
• Servo Motors• Video Camera• Video Transmitter• Video Receiver
RF ReceiverSpeed
Controller
VideoTransmitter
Servo Motors
ElectronicMotor
RF Transmitter
Control System
BatteryVideo
Receiver
VideoCamera
RF ReceiverSpeed
Controller
VideoTransmitter
Servo Motors
ElectronicMotor
RF Transmitter
Control System
BatteryVideo
Receiver
VideoCamera
Block Diagram of MAV Electronic System
47
Electronic Considerations – Electric Motor
• Electronic Motor includes three (3) types:– Brushed– Brushless– Coreless
• Selection Criteria– Weight– Current– Thrust– Propeller configuration
• Optimize using gathered data given propeller specifications.
Coreless DC Motor
Brushless DC Motor
Brushed DC Motor
Average Thrust @ 7.4V vs Maximum Current
Thrust = 32.982(i) + 47.252
R2 = 0.9863
0
100
200
300
400
500
600
700
0 2 4 6 8 10 12 14 16
Maximum Current (Amps)
Av
era
ge
Th
rus
t (g
ram
s)
48
Electronic Considerations - Battery
• LiPoly Batteries will provide the necessary power for all of the onboard electronics (present and future).
• LiPoly chosen over nickel metal-hydride (NiMH) and nickel-cadmium (NiCad) for high charge density
• Optimal battery selection by using the charts below
Current Rating vs. Mass for Different Single Cell (3.7V) Lithium Polymer Batteries
i = 0.1565(m) + 0.3209
R2 = 0.9288
0
1
2
3
4
5
6
7
8
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0
Weight (Grams)
Cu
rre
nt
Ra
tin
g (
Am
ps
)
LiPoly Batteries
Lifetime vs. Mass for Different Single Cell (3.7V) Lithium Polymer Batteries
tlif e = 48.195(m) - 21.067
R2 = 0.9745
0
500
1000
1500
2000
2500
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0
Weight (Grams)
Lif
eti
me
(m
Ah
)
49
Electronic Considerations – Control System
• Control System includes two (2) components:– RF receiver– Speed controller
• Selection Criteria– Number of channels– Compatibility with existing
RF transmitters– Size– weight– Range– Motor compatibility
Speed Controller
RF Receiver
RF Transmitter
50
Electronic Considerations – Future Requirements
• Future Technology:– Two (2) servo motors– A video surveillance
system
• Considerations– Weight– Dimensions– Power requirements
Video Camera Video Transmitter
Video Receiver Servo Motor