DESIGN & IMPLEMENTATION OF LOW SPEED AUTONOMOUS UAV POWERED BY HYBRID FUEL CELLThesis proposal By Muhammad Zulkifli 38926 Advisor: Dr. Mohammad Al Jarrah

Outliney Problem Overview y Introductiony y y y

Background Thesis Objectives Literature survey Literature Summary

y y y y y y y2

Problem Statement Thesis Contribution Thesis Work Roadmap Methodology Initial Result Conclusions References

Problem Overview

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Source: [11]

Introduction - Backgroundy Small electric powered UAV endurances are mostly around 2 to 3

hoursUAV Skylark Skyblade III Raven Puma Bird Eye 400 Bird Eye 650 SpyLite MTOW [Kg] 5.5 5 1.9 5.9 5.6 11 6 Wing Span [m] 2.2 2.6 1.4 2.8 2.2 3 2 est Endurance [mins] 120 60 60 to 90 120 60 180 90

Mostly are powered by an onboard battery. It is desirable to improve the endurance of this type of UAV.

Source:[1],[16] to [21] &[12]4

Introduction - Backgroundy Challenges: y Low Specific Power y Typically less than 1 kW/kg [31] y Requires an optimum design solution of UAV which able to be operated at FCs rated power y Propulsion system components have to be carefully selected to meet the FCs rated power y Fuel Cell performance is not easy to predict y Requires fuel cell actual data for building the validated model of the fuel cell system

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Introduction - BackgroundSeveral Hybrid Fuel Cell systems available in the market for UAV applicationManufacturer Model Rated Power [Watts] Rated Output Voltage [V] Rated Output Current [A] Peak Output Power Fuel Cell Type Reactants number of Cells Reactant Storage Type Tank Capacity [L] Total Weight [Kg] Net Energy Available Hybrid Horizon AEROPAK 200 24 8.5 500 PEM H2 & O2 35 H2 Gaseous 1.1 2 900 Wh Yes EnergyOr EO-210-LE 210 30 850 PEM H2 & O2 H2 Gaseous 2.95 900 Wh Yes Protonex UAV-C250 250 17 15 500 PEM H2 & O2 H2 Sodium Borohydride Fuel Cartidrige 1.5 L 3 1500 Wh Yes

In this work AEROPAK is used because it is already available in AUS Aeronautics lab Source:[13] to [15]6

AEROPAK (PEM Fuel Cell) [13]

20v to 32v

Load

300 watt for 1 min

-

Li-Po +

- Fuel Cell Stack +7

200 watt continuous

Thesis Objectivesy Design and implement an autonomous small electric

UAV system that able to fly with endurance beyond the battery powered electric UAVs. y Integrate the hybrid fuel cell into an autonomous UAV system. y Conduct flight tests to evaluate the maximum endurance of the autonomous hybrid fuel fell powered UAV system

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Literature Survey Fuel Cell UAV Design[5]

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Uses design space exploration on high level design task by a grid search. The optimal designs identified in the high-level conceptual design task as the basis for the detailed design of the aircraft components. Matching motor and propeller to the characteristics of a given fuel cell is the most important aspect of a successful design.

Literature survey- Fuel Cell UAV Design [7]

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The approach of design is using the conventional method and pure fuel cell as power source. The author suggests a high aspect ratio wing is desired to efficiently utilize the low power-to-weight ratio of the fuel cell power plant that was available. Use the advantage of CAE software to help verifying the design performance estimation.

Literature survey- Fuel Cell UAV Design [8]

The hybridization fuel cell with the battery will give UAV higher power than the rated power of FC for short time. The propulsion system components are optimized through dyno-test in static & wind tunnel environment. The methodology of design is not clearly explained specifically in this paper.11

Literature survey- Fuel Cell UAV Design [4]

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Uses the method which developed by Moffit[5] for conceptual design purpose. The UAV power plant design and optimization is done by investigate the propulsion system components in ModelCenter 8.0 a commercial optimization software. The fuel cell system uses a proprietary design developed by UTRC. The HiLS result is promising for the fuel cell UAV to achieve 24 hour endurance. The UAV that fly using autopilot during the cruise consumes power 60% less than the piloted (RC controlled) flight. Hybridization of fuel cell/battery is not considered in this work.

Literature survey- Fuel Cell UAV Design [6]

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Focused on the design method to develop a hand launch UAV for long endurance operation. Uses multi disciplinary design tools coupled with an optimization routine. Incorporate hand launch analysis and uses battery as power source. Uses the genetic algorithm to solve the optimization problem. Incorporated the hand launch analysis in the design tool. The propulsion system components are commercially off the shelf. The simplified aerodynamic analysis.

Literature survey UAV Fuel Cell Propulsion System [9]

SOFC fuel cell. Physical based model at steady state condition. The fuel cell model is linear model on the ohmic region. Approximated by Thevenin equivalent circuit. (Vc =Voc IcRth)14

Literature survey- UAV Fuel Cell Propulsion System [3]

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At steady level flight the hydrogen consumption is at the lowest. Hybrid system allows decoupling of the aircraft power design requirement for climb and cruise. The integrated design process that utilize this decoupling can improve the performance of hybrid fuel cell over conventional powered aircraft. The degree of hybridization (DoH) will constraints the power required of the fuel cell. Only consider the charge depleted battery through the time, no recharging mechanism involve during the flight.

Literature Summary Conventional design approach only cannot guarantee the delivery of an optimal design for hybrid fuel cell UAV. The selection and matching of propulsion system components should be strictly optimized for long endurance UAV design. Generic algorithm optimization offers multiple near optimal design solution. The power consumption also affected by the operation of the flight is carried out by the pilot. Implementation of autopilot can improve this. A validation of the multidisciplinary design analysis tool is required to check the fidelity of the model used for analysis.

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Problem StatementIn the process of addressing the challenges, the following points will be addressed:y Develop a multidisciplinary design and optimization tool for

high level design of a small electric long endurance UAV y Develop model for the propeller, brushless dc motor, and hybrid fuel cell system to be integrated in design tool y Build an experimental setup for validation of the propulsion system models y Manufacture the UAV airframe y Integrate hybrid fuel cell, auto pilot & UAV airframe and conduct the flight testing of the manufactured UAV with hybrid fuel cell system running on board17

Thesis Contributionsy Develop and implement a high level multidisciplinary

design and optimization tool for UAV platform (similar approach as [6]) by integrating the hybrid fuel cell block into it.

AUS scope :y Manufacture & flight testing an UAV platform which

powered by a hybrid fuel cell y Build an experimental test setup for propulsion system testing with variable wind speed 0 to 30 m/s (installed inside the wind tunnel)18

Work RoadmapManufacturi ng, System Integration, & Flight Testing

Multidisciplinary design & Propulsion optimization system Analyze and optimize the design of UAV to achieve model maximum endurance Baseline Design Configuration19 Initial study of the design of UAV Build the model propulsion system to be used in design analysis

Validation and HiLS

Methodology Baseline Configuration Design [2],[22] Feasibility Analysis[29]

Evaluates the drag coefficient when the maximum power required for cruising (T=D) Taking the maximum continuous power that can be delivered by Hybrid Fuel Cell AEROPAK (200 W) as maximum power required

Configuration StudyThree common configurations are compared and consider which one is the most reasonable configuration to use.AUS DBF 2010Criteria Aerodynamic Efficiency Manufacturing Complexity Stability Internal volume TOTAL Conventional 3 3 2 3 11 Canard 2 1 3 2 8 Tandem Wing 2 1 3 2 8

[28]

*) 3 : good, 2:average, 1:poor

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Methodology Propulsion System Synthesis

[3]

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Propulsion System Synthesis Propeller Modelling [23]

The vortex theory of screw propeller approximate the propeller as a lifting surface and analyzed as a lifting line. The lifting surface consist of finite number of airfoil sections22

Propulsion System Synthesis Electric Motor Modelling [9],[24]y The electric motor is brushless DC motor modeled at steady state

condition since the focus on performance during cruise where mostly using constant duty cycle.

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Propulsion System Synthesis Motor Speed Controller Modelling [9],[10]

Brushless DC motor requires external controller to switching the commutating sequence The duty cycle, D, determines how much current delivered to the motor

with assumption that the losses of the controller are neglected24

Propulsion System Synthesis Fuel Cell Modelling [26],[3]y

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Optimization Routine [6],[32]y Design Constraints:

Conventional aircraft configuration design with single motor propulsion The wing & tail airfoil are predetermined The specification of fuel cell is fixed according to AEROPAK Specification The propeller type is limited for electric motor propeller type The propulsion system components are commercially available from off the shelf components y Problem Characteristic: Mixture of discrete variables (i.e. motor constants & gear ratio) and continuous variables (i.e. wing size, AR, weight) Involve many possible combinations of propulsion system components Continuity of design space could not be guaranteed No closed form solution26

Optimization Routine [6],[32]y Optimization Algorithm: Genetic Algorithm y Offers multiple near optimal solutions y The most feasible & has relatively higher endurance among the design solutions will be chosen as the final design. y The chosen design will be continued for detail design stage

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HiLS of Propulsion System [30]

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Propeller Analysis Result0.12 J = 0.0 0.1 0.08 Cha nge in P ropeller Coe ffic ients with z eta 0.06

P ropeller P erform anc e C oeffic eints Dis tribution Ct Cq Cp

0.04

0.02

0

0

0.1

0.2

0.3

0.4

0.5 z eta (r/R)

0.6

0.7

0.8

0.9

1

P ropeller A irfoil S hape @ r 0.2 data 1 4th degree data 2 data 3 data 4 data 5

y = - 0. 9828*x + 1.379*x - 0.8791*x + 0.4922*x - 0.001283 0.15

4

3

2

XFOIL

0.1

0.05 Y /C 0 -0.05 -0.1 -0.15

0

0.1

0.2

0.3

0.4

0.5 X/C

0.6

0.7

0.8

0.9

1

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Initial Result Fuel Cell TestingObjective: to obtain the polarization curve of the hybrid fuel cell

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Initial Result Fuel Cell TestingPower, Current, and Voltage delivered to the load.

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Initial ResultPolarization scatter data of the fuel cell stackF uel c ell s tac k A E R O P A K 40 200 V oltage P ower 35

30

25 V ol tage, v olts P ow er, w att s

20

100

15

10

5

0

0

1

2

3 C urrent, A m peres

4

5

6

0

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Initial ResultPolarization scatter data of the hybrid fuel cellA E RO P A K Hy brid F uel c ell 32 350 30 Total voltage 280 Total P ower 28

210 V ol tage, v olts P ow er, watt s 140 70 20 0 4 8 Current, A m peres 12 16 0 26

24

22

18

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ConclusionsWork Done: y Propeller modeling and analysis module is done y Fuel Cell polarization data are obtained y Baseline configuration design of UAV is done y Wing airfoil has been selected Work To be Done: y Develop a multidiscipline analysis y Implement the optimization procedure y Manufacture the UAV y Test the propulsion system on bench test and HILS platform y Flight testing the integrated UAV system34

References[1] E. Systems, SkyLark I-LE, Elbit Systems. [2] D. P. Raymer, Aircraft design : a conceptual approach, Reston, Virginia: American Institute of Aeronautics and Astronautics, 2006. [3] T. H. Bradley, B. A. Moffitt, D. E. Parekh, T. F. Fuller and D. N. Mavris, "Energy Management for Fuel Cell Powered Hybrid Electric Aircraft," in 7th International Energy Conversion Engineering Conference, Denver, Colorado, 2009. [4] G. D. Rhoads, N. A. Wagner, B. J. Taylor, D. B. Keen and D. T. H. Bradley, "Design & Flight Test Result for 24 Hour Fuel Cell Unmanned Aerial Vehicle," in 8th Annual International Energy Conversion Engineering Conference, Nashville, TN, 2010. [5] B. A. Moffitt, T. H. Bradley, D. E. Parekh and D. Mavris, "Design and Performance Validation of a Fuel Cell Unmanned Aerial Vehicle," in 44th AIAA Aerospace Sciences Meeting and Exhibit, Reno, Nevada, 2006. [6] N. Wagner, S. Boland, B. Taylor, D. Keen, J. Nelson and T. Bradley, "Powertrain Design for Hand-Launchable Long Endurance Unmanned Aerial Vehicles," in 47th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, San Diego, California, 2011. [7] C. Herwerth, U. Ofoma, D. C. Wu, S. Matsuyama and S. Clark, "Development of a Fuel Cell Powered UAV for Environmental Research," in 44th AIAA Aerospace Sciences Meeting and Exhibit, Reno, Nevada, 2006. [8] C. Chiang, C. Herwerth, D. Mirmirani, A. Ko, S. Matsuyama, S. B. Choi, D. Gamble and D. Arena, "Systems integration of a hybrid PEM fuel cell/battery powered endurance UAV," in 46th AIAA Aerospace Sciences Meeting and Exhibit, 2008. [9] P. Lindahl, E. Moog and S. R. Shaw, "Simulation, Design and Validation of a DAV SOFC Propulsion System," in IEEE Aerospace Conference Proceedings, 2009. [10] B. A. Moffitt, "A Methodology for The Validated Design Space Exploration of Fuel Cell Powered Unmanned Aerial Vehicles," Georgia Institute of Technology, Atlanta, Georgia, 2010. [11] Mark Okrent, "European Civil UAV Roadmap 25 Nations for a European Breakthrough," in EU 10 Conference, Berlin, Germany, 2006. [12] C. E. Thomas, "Fuel Cell and Battery Electric Vehicles Compared," International Journal of Hydrogen Energy , Vols. 34 (2009) 6005-6020, 2009. [13] H. E. System, AEROPAK Fuel Cell Power System : Operation and Maintenance Guide, Singapore: Horizon Energy System, 2009. [14] E. T. Inc., EPOD EO-210-LE / EO-210-XLE, Montral, Qubec, Canada: EnergyOr Technologies Inc., 2009.

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References[15] P. T. Corporation, UAV-C250 advanced uav propulsion power source, Southborough, MA: Protonex Technology Corporation, 2009. [16] I. A. I. M. Division, Bird Eye 400 - Third Generation Mini UAV system, Israel Aerospace Industries. [17] I. A. I. M. Division, Mini UAS Bird Eye 650, Israel Aerospace Industries. [18] AeroVironment, Puma AE, AeroVironment. [19] AeroVironment, Raven, AeroVironment. [20] B. A. S. Ltd, SpyLite, Kadima: Bluebird Aero Systems Ltd. [21] S. T. A. Ltd, "ST Aerospace," [Online]. Available: http://www.staero.aero/www/keyoffering.asp?serkeyid=ODAwMDAwMTg. [Accessed 23 December 2011]. [22] D. J. Roskam, Airplane Design I - VIII, DARcorporation, 1997. [23] W. F. Phillips, Mechanics of Flight, John Wiley and Sons, 2004. [24] A. Hughes, Electric motors and drives: fundamentals, types, and applications 2nd Ed, Newnes, 1990. [25] M. Ehsani, Y. Gao and A. Emadi, Modern electric, hybrid electric, and fuel cell vehicles: fundamentals, theory, and design, CRC Press, 2009. [26] I. EG&G Technical Services, Fuel Cell Handbook (Seventh Edition), Morgantown, West Virginia: U.S. Department of Energy Office of Fossil Energy National Energy Technology Laboratory, 2004. [27] P. technology, Kestrel User Guide : Kestrel Autopilot & Virtual Cockpit 2.4.2, Procerus technology, 2007. [28] T.-0. Team, "TAIWAN UAV DESIGN BUILD FLY COMPETITION 2008 TANDEM WING CONFIGURATION NS 01 STRIGATE," DEPARTMENT OF AEROSPACE ENGINEERING FACULTY OF MECHANICAL AND AEROSPACE ENGINEERING INSTITUT TEKNOLOGI BANDUNG, Bandung, 2008. [29] "EZ.ORG," [Online]. Available: http://www.ez.org/. [30] S. Adiansyah, Mazari UAV adaptive autopilot design and implementations [31] B. A. Moffitt, "Design and Hardware Validation of a 24 Hour Endurance Fuel Cell UAV," in 16th Annual External Advisory Board - Aerospace Systems Design Laboratory, Atlanta, GA, 2008. [32] C. Onwubiko, Introduction To Engineering Design Optimization, Prentince Hall, 2000.

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