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Group 1 - Management, systems integration and reporting. 2011 Daniel, Matt, Tony, Sam, Mayur. Mission Task. Search and rescue UAV Requirements. Allocations of Groups & Members. 1. Management 2. Mayur - Payload & Electrical Power 3. Matt - Aerodynamics 4. Daniel - Structures - PowerPoint PPT Presentation
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Engineering
Group 1 - Management, systems integration and reporting2011Daniel, Matt, Tony, Sam, Mayur
Mission Task Search and rescue UAV
Requirements
Allocations of Groups & Members 1. Management
2. Mayur - Payload & Electrical Power
3. Matt - Aerodynamics
4. Daniel - Structures
5. Sam - Propulsions
6. Tony - Weights and Balance
7. Matt - Launch & Retrieval
Communications Overall group meeting
Management meeting
Management attending sub group meetings
Resolving conflict Good vs bad
Optimal design vs realistic
Engineering
Group 2 - Payload and Electronics
Payload Design
Payload - Contents• One man life raft• EPIRB• Flares • Heliograph• Food Supplies• 1.2L water• Heat Packs• Torch• Circuitry for lights
Payload - Final Design
Payload - Final Design
Payload - Final Design
Payload - Layout
Payload - Final Design
Payload - Dropping and Retrieval• The payload is dropped to land upwind of the person
o This means the wind will push it back towards the person • A rope follows the payload with a drogue, landing near the
person for retrieval• The person can then access everything that is stored in the
payload, which is attached with velcro
Engineering
Autopilot and Flight Control
Group 2 - Payload and Electronics
Autopilot SystemMission Computer• Decides where to fly• Is responsible for
communications• Searches for person (via FPGA)
Flight Computer• Controls the aircraft• Gets info from sensors• Continually monitors
location/speed/attitude
Search Pattern
Search Pattern
Electronic Connections
Engineering
Control and Comms
Group 2 - Payload and Electronics
ControlRequires +-20 degree deflection
4 bar linkage chosen, directly driven by servo
Servo mounted inside wing, linkage mount attached directly to the surface of the flap.
Battery Powered.
Chosen for relatively light weight and small size compared to alternatives: hydraulic actuators, direct rotation
For greater range of motion, or higher torque, gearing can be be implemented for relatively small weight gain.
For wing servo PS-105, high torque servo 35Nm, +-45 degree range of motion, requires 18 W each
For tail servo, K-2000 servo, 10 Nm torque, +-45 degrees of motion, requires 9 W each
For throttle, Futaba Brushless servo, 3Nm torque, low power requirements.
Flap Actuator
Radio BroadcastDirect Line of sight impossible at search height
Typical video surveillance (Ku, C and S) bands affected by rain
Broadcast in L Band to avoid effects of Rain fade
Satellite phone for telemetry broadcast
1.5" square Iridium Antenna for receiving signal
RF unit to receive radio signal close to ship for direct control in case of emergency
h =781m above search height of 200mL = 100km no change to range
Telemetry SentDuring normal flight
Status(Cruise, Search, Loiter, Return)Location (from Gps) SpeedAltitude
Distance to search area
During search
As above plus wind speed
For positive identification, photo location
Sends 50 by 50 pixel relevant section of photo to minimise bandwidth
Termination protocol
Ship sends confirmation signal every 10 seconds, if UAV loses contact for 10 minutes vehicle will terminate.
If ship is not receiving telemetry, ie. satellite link down, will send instruction to UAV to re-establish uplink every 10 seconds, if UAV continues to receive this signal for 10 minutes will terminate.
Telemetry Display
Engineering
Group 3 - Aerodynamics
Louis GysbertsSam LudowykPhoebe RyanRoonal JepaulBoitumelo Makgantai
Key Tasks
Wing/Tail configuration
Wing/Tail geometry and sizing
Estimation of aerodynamic parameters
Performance
Design Evolution
Aerofoil Selection
Tail Volume Coefficient and Sizing
400
L
1.3 m
NX Drafts
Engineering
Group 4 Structures
Leo PasukovThomas SleeAmanda NealNabil ChowdhuryNayeem Chowdhury
Initial wing structure for first iteration structural analysis
A representation of the complete wing and fuselage attachment system
Initial Fuselage Design to accommodate payload and air cannon launch with pusher propellers located under the wing facing the back of the vehicle
Hermes 450 on left and RQ7 Shadow on right
Structural components of the Fuselage
Modification of fuselage for payload and wing
Forces acting on the Fuselage
Stresses on the fuselage
Total Deformation on Fuselage Structure
Forces and moments acting on the Motor Mount
Determining the total deflection of the Motor Mount and equivalent Stress of Motor Mount
The general shape of the inverted V-tail
The ruddervators end before the apex of the inverted V, and provide the design with some aesthetics.
The internal structure of the tail
Screws hold the boom and tail structure together via these screw holes
Layout Drawing Wing
Layout Drawing Wing Mount
Layout Drawing Fuselage
Layout Drawing: Motor Mount
Layout Drawing: Tail
Engineering
Group 5 – Propulsion System
Michael Hamilton – 21490902Tom Mason – 21456038Timothy Robinson – 22052577Jordan Hannagan – 22084843Nick Tegg – 22063617Neeraj Chadee - 21739897
Initial Concepts Rejected Concepts
– Twin engine tilt rotor• To Heavy• To complex
– Twin engine wing mounted• To heavy• Power not required
Pursued Concepts
– Ducted Fan• Analysed but later dismissed
– Final Pusher prop design
Ducted Fan Can significantly increase aircraft
velocity
– <190Km/h– Beneficial for Search and
rescue Beneficial for low speeds and TOL
where high thrust demands
Introduces significant aerodynamic design considerations
Ultimately to heavy and hence design was scrapped
– Weight increase equivalent to second engine
Engine Selection Chosen engine is Wankel AR731
Heavily influenced by historical evidence
Specifically designed UAV Engine
Weight of 10kg
Zero radial Vibration
– Due to rotary motion
Engine Components The Engine requires:
– Generator– Intake and Filter– Carburettor– Oil and Fuel Pump– Oil Tank
These components will fit in the space between engine and rear bulkhead
Engine Mounting Must be able to transmit engine
loads to main fuselage frame
Four point frame made from Titanium
Will weight only 0.136kg Leaves sufficient room
for engine components Maximum deflection
under maximum load < 0.002 mm
Propeller Design and Selection Historical comparisons were used for
initial design and analysis
Simplistic then more refined methods were used to calculate output
Custom sized and shape propeller was designed based on scaling approach
– Commercially available would be betted due to
– Expendable nature Material Selection
– Wood or Fibreglass• Chosen because• Relatively cheap 0 20 40 60 80 100 120
050
100150200250300350400450 Thrust vs. Velocity
5400 RPM6000 RPM6600 RPM7200 RPM7800 RPMCruise VelocityDrop Velocity
Velocity (m/s)
Thru
st (N
)
Group Interactions Could undertaken majority of analyses independently
At time couldn’t proceed as waiting out other groups results
– spiral effect Had to assume accuracy of other teams results and conclusions
– Possibly leads to over Engineering Group meetings were critical to Progress
Engineering
Group 6 – Weights and Balance
6. WEIGHTS AND BALANCE
Importance of Weights and Balance Total weight of aircraft ≤ Lift produced by the wings
Weight changes
Things to be considered before flying
Weight
=+
Initial Assumptions
Unit
kg 62 19.836 29 10 91 120.836
Weight of UAV along the mission
Take-off
Search
Cruise
Climb
Cruise
Drop
Descend
Land
Weight of UAV along the mission
• ???? initial assumption not good• Iterate with • Iterate until , apply factor of 2 for fuel reserve
Unit
kg 62 19.836 7.31 10 91 99.146
1 0.9967 0.9953 0.9042 0.9924 0.995 1
Balance Find the CG
Requirement??
- Wings and tail designed with CG at 0.25MAC
- Tail moment arm length = 60% UAV length
- Length of UAV = 3400mm
NO! Just keep CG at 0.25MAC
Changes made while balancing UAV
- Fuselage was short and fat, CG is around 0.8MAC
- Lengthen fuselage
- Reduce diameter of fuselage
Final Layout of UAV
Final Layout of UAV Total Length = 4925mm
Fuselage Length = 2600mm
Fuselage Diameter = 400mm
Tail Moment Arm Length = 2600mm
Difficulties Conflicts that arose during calculations
Conclusion Contributions of Weights and Balance group in the UAV project
Visions
Engineering
Group 7 - Launch & Retrieval
Requirements
Accelerate the UAV to suitable speed.
Be installed and maintained on a marine vessel.
Reusable
Must in no way damage the aircraft.
Operate in an easily controlled and consistent manner.
Be safe and simple to operate
Launch System
Possible Solutions
Primary Design Considerations Mass to be launched Structural loads
– On UAV and within the launch system Reliability Available resources (electrical power etc.) Spatial constraints (boat)
Final Design
Pneumatic launcher
Final Design
Launch ‘Cradle’
Requirements
Decelerate the UAV to rest
Be installed and maintained on a marine vessel.
Reusable
Must in no way damage the aircraft.
Operate in a consistent manner.
Be safe and simple to operate.
Retrieval System
Possible Retrieval Solutions
Primary Design Considerations Mass to be decelerated
Structural loads – On UAV and within the retrieval system
Spatial constraints (boat)
Reliability
Final Design
Final Design
Ratchet System
Spring -Damper System
Engineering
End of Slides, thank you!