HALE UAV Technology

Maximum 48 Hours Endurance

Maximum 48 Hours Endurance

Potentially Unlimited Endurance

Potentially Unlimited Endurance

Cognitive UAV Mission Requirements

  • Rapidly deployable, highly survivable ISR platform
  • Ability to take-off from small general aviation runways (4000ft x 75ft)
  • Loiter at 60,000 ft for 15 days with 99% probability of station keeping
  • Payload is assumed to be 250 lbs and the power consumption is 1.5 kW – distributed among the cellular aircraft

Cognitive UAV Concept

Solar Cell / Rechargeable Battery Technology

Solar CellType

Power Density

 (W/ft2)

Areal Density 

(lb/ft2)

Efficiency (%)
Sunpower A300Thin Film Cell18.60.14320
Emcore IMMThin Film Cell30.6> 0.1~ 33
  • Commercially available thin film solar cell efficiencies ~20% 
  •   Will approach 30% in near future
BatteryBattery ChemistryMax. Discharge (C)Voltage (V)Energy Density
Sanyo UR18650FLithium-Ion23.7191 W-h/kg
Varta PLF 523450Lithium Polymer23.7231 W-h/kg
SION Power CellLithium-Sulfur23.6350 W-h/kg

Emcore IMM-3J

Lithium Sulfur Cell

Lithium Polymer Cell

Conceptual Design Process

Conceptual Design Trade Study Conclusions

  • Minimizing the drag is imperative and retracting or eliminating the landing gear has a significant impact on designs limited by battery energy density
  • Select a power loading of 30 W/lbs as there is little difference in the impact of a power loading of either 20 or 30 W/lbs
  • For the current battery technology 8 linked vehicles offer a significant increase in mission feasible days

Cellular UAV Conceptual Design

e

0.8

CDo

0.008

W/S

1 psf

(P/W)max

30 W/lb

AR (cellular)

5

AR (docked)

40

Wingspan (cellular)

67 ft

Wingspan (docked)

536 ft

W (cellular)

900 lbs

W (docked)

7200 lbs

Feasible Mission Days

187 

CLcruise

1.17

 

Cellular UAV Conceptual Design

  • Developing in-house autopilot for docking demonstration using PC-104 stack
  • Simulation of linked vehicle dynamics and control
  • High level communication and control for vehicle coordination and threat avoidance
  • Optimal trajectory determination for docking when taking close proximity aerodynamics into account
  • Simulation of the Cognitive UAV mission in Flight Gear

Risk Mitigation Flight Testing

Evaluate the high risk technologies

    • Demonstrate the integration of local proximity sensor technology in a flight environment 
    • Achieve autonomous close formation flight maneuvers with two vehicles

Reduced risk considerations

    • Use proven commercial off-the-shelf components, including the vehicles and autopilot system
    • The flight maneuvering, speed, and performance objectives are minimal.

Desired outcome from flight tests

    • Computer-controlled flight maneuvers with separations of less than one wingspan using onboard sensor augmentation.

Subscale Vehicle Design

  • Based on the conceptual design, the preliminary design of the subscale cellular vehicle was made
  • This vehicle will be fabricated in 2011 and flown in 2012.

Parameter

Value

Aircraft Weight

185 lbs

Wing Span

20 ft

Wing Root Chord

3.96 ft

Wing Tip Chord

3.96 ft

AR

6.19

Static Margin

8 %

L.E. Spar Diameter

5 in

T.E. Spar Diameter

1.5 in

Docking Vehicle Design

  • A low cost custom vehicle is being designed and fabricated by NextGen to demonstrate in-flight tip-to-tip docking of UAVs
  • This aircraft will be fabricated in 2010 and flight tested in 2010-2011

Parameter

Value

Aircraft Weight

120 lbs

Wing Span

13.5 ft

Wing Root Chord

2.2 ft

Wing Tip Chord

2.2ft

AR

6.19

Aircraft Length

10.8 ft

Aircraft Height

3.6 ft

Static Margin

10 %

L.E. Spar Diameter

4 in

T.E. Spar Diameter

2 in

Vehicle Docking Concept

  • A ball and socket docking mechanism was selected bas on assessment of possible mechanisms
  • A soft docking boom is extended from the aircraft wingtip during flight to the tip of the adjacent aircraft
  • A hard dock is then performed at the leading and trailing edges as the soft docking boom retracts
  • Three docking mechanism prototypes have been designed and fabricated
  • Their performance will be fully characterized with benchtop testing and the final selection will be made

Docking Mechanism Design

Electromagnet / Mechanical Plug Hard Dock

Permanent Magnet (Ball and Socket/Plug) Soft/Hard Dock

Electromagnet (Ball and Socket) Soft/Hard Dock

Progression of Flight Test Vehicles

Vehicles

Size and Uses

Sailplanes

Span:

Weight:

Tests:

21.5 ft

57 lbs

Risk reduction, AP piggyback

Docking Vehicle

Span:

Weight:

Tests:

14 ft

120 lbs

Docking demonstration

Sub-scale Cellular

(33%)

Span:

Weight:

Tests:

22 ft

187 lbs

Subsystems, High/Low level controls

Full-scale Cellular

Span:

Weight:

Tests:

66 ft

900 lbs

High altitude, Energy management

 

Goals for the Cognitive UAV Program

During the next two years NextGen will demonstrate key technologies in the Cognitive UAV program:

  • Be the first to successfully demonstrate autonomous in-flight tip-to-tip docking of the cellular UAVs
  • Complete design and manufacture subscale versions of the Cognitive UAV cellular aircraft
  • Develop custom in-house cognitive control system capable of coordinating a group of cellular UAVs and docking tip-to-tip in flight