SOARS

1. SOARS Self Organizing Aerial Reconnaissance System Matt Edwards Arseny Dolgov John Shelton Johnny Jannetto Galina Dvorkina Nick Driver Eric Kohut Kevin Eberhart Preliminary Design Review ASEN 4018 Senior Projects 10/16/06 1

2. Presentation Outline • Overview and Objectives • System Architecture • Requirements Flow-down • Subsystem Design • Imaging • Slave Aircraft Selection • Controls • Power • Communications • Risk Analysis and Feasibility • Organization & Scheduling • References • Appendix 2

3. Overview • Objective: Design, build and test an autonomous aerial system (UAS) capable of imaging multiple targets within a 1km circle as quickly as possible with 99% probability of object detection (according to Johnson criteria). 1. AFRL COUNTER Project. Used with permission. 3

4. Top Level Objectives & Requirements Slave Truck hmax = 70 m Target θ (X,Y,Z) • Image at least 3 targets within a 1km radius of stationary (assumed) Master vehicle in under 8 minutes • Targets given by GPS location and heading • Motivation: COUNTER project • Low-altitude surface imaging • Minimizing risk to larger Master vehicle • Seeing inside vehicles, structures 4

5. Vehicle Constraints • Master UAV: SIG Rascal 110 (COUNTER project estimated capability) • Wing Span: 280 cm • Payload: 3 kg • Slave UAV • Max weight: 1.5kg • Maximum width for below-wing mounting: 120 cm 5

6. Test Scenario 6

7. Deliverables Actual Mission Target System • Selection of slave vehicle • GS to Master to Slave RF link • Image reception • Target specification • Slave telemetry (GPS, attitude) • 3 Images taken with correct position, attitude (Johnson criteria) • Autonomous navigation • Deployment feasibility 7

8. System Architecture 8

9. Slave Flow-down 9

10. Master Flow-down 10

11. Ground Station Flow-down 11

12. System Architecture Options Slave Vehicle Options and Assessment

13. Subsystem: Imaging Overview: • The Geometry of the Imaging Problem • Derived constraints • Imaging Conclusions 13

14. Imaging: Geometry • Blur is the driving factor in the imaging geometry • Blur results from camera motion while imaging. Motion can be: • Radial with respect to target • Tangential with respect to target • Rotating with respect to target (pitch or yaw) • Roll

15. Imaging: Geometry • The Maximum Pitch (or Yaw) Rate Equation • Definitions • Range to Target (r) • Length of Target (L) • Radial velocity: velocity component • directly toward center of target • Assumptions • Target is sufficiently far away that • Blur due to rotational velocity is defined as • Equation Apparent location of target at time t1 Apparent location of target at time t2 Actual length of target (L) Blurred image 1 Range (r) 0 Change in camera angle () Direction of Imager’s rotation

16. Imaging: Geometry • Calculating the imager’s maximum pitch and yaw rate: Plot generated for target length L = 1 m and exposure time t = 0.01 s • Beyond 100 m range, maximum rotational velocities are too small for feasibility • Derived requirement: range <100m

17. Imaging: Geometry • Using Johnson Criteria to Find Maximum Field of View: Johnson Criteria: For an object to be statistically recognizable, it must have at least 6 or 7 lines of resolution contained within it. • Cameras in our price range run 700 lines or less • Max imaging range was determined to be 100 m • The Field of View for our camera should be no more than 60º

18. Imaging: Geometry Conclusions • Field of View • FOV: <60º • Imaging Range • R: 5-100 m • Speed of Slave • During imaging, the slave should travel at a rate between 5 - 100 m/s • Angular Rates: • Pitch: 100 °/s • Roll: 100 °/s • Yaw: 60°/s • Tests need to be performed to determine actual aircraft jitter

19. Subsystem: Slave Vehicle • Overview: • Vehicle selection trades • Stability experiments • Feasibility 19

20. Aircraft Selection Trade Matrix 20

21. Aircraft Selection: Stability Experimental Verification: 1. Wind Chamber experiment a. Mount vehicle to wind chamber floor at CG location b. Apply free stream velocity equal to that of vehicle during mission c. Apply longitudinal impulse perturbation d. Measure impulse response with accelerometers 2. Theoretical Verification: a. Take dimensional measurements of aircraft to determine stability derivatives b. Integrate body frame equations of motion c. Apply impulse perturbation to system of equations and determine time response

22. Subsystem: Autopilot & Controls • Overview: • Control Method • Autopilot Trade Study 22

23. Autopilot: Control Model • Use of Lyapunov field for pointing and direction control (estimate below) • Field would be switched as new target sent to Slave and previous target image acquired. Field appears as point from far away • Green area marks location of imaging

24. Autopilot: Options • Modified CU System • Cost: ~$450 • PIC Microcontroller • Onsite help from Aerospace Students and Faculty • Source Code Obtained • COTS (Baseline: Micropilot) • Cost: ~$6000 • Additional cost of $1500 to modify control algorithms • Build from Scratch • Cost: ~$500 • Additional time to develop trades and parts

25. Autopilot Platform Trade Study • Modification of CU System found to be best option • Team has experience with using the PIC Microcontroller • Imaging testing will be done concurrently with Microcontroller course project • Modification details will be determined as pointing requirements are finalized with testing • Changeability of control algorithms and software is important as the vast majority of autopilots circle around a GPS waypoint or go to a GPS waypoint

26. Subsystem: Power Overview: • Battery Selection • Motor & Propulsion Investigation 26

27. Battery Selection • Choose Cell Chemistry • 4 Most Popular Chemistries • Design-to: • 8 min flight time • >10A current draw at 7V

28. Motor & Propulsion Investigation Determine best propulsion methods & motor types Design-to: >150g thrust 8 min flight time

29. Subsystem: Communications Overview: • Master transceiver trade study • Slave transceiver trade study

30. Comm: Master Trade Study • Master Design-to: • 200kbps data rate • >2km range Aerocomm AC4790-200 was chosen as the optimal module 30

31. Comm: Slave Trades • Slave Design-to: • 115kbps data rate • >1km range Aerocomm AC4790-200 was chosen as the optimal module 31

32. Risk Analysis • Overview: • Fault tree • Risk Matrix • Design Fallbacks 32

33. Risk Analysis: Fault Tree 33

34. System Risk Matrix Airframe unable to meet stability requirements Autopilot unable to meet stability/pointing requirements with chosen airframe. Deployment not feasible Airframe unable to meet payload/ endurance requirement Power system & batteries unable to meet endurance requirement Camera unable to meet Johnson Crit. requirements Comm system unable to meet bandwidth/range requirements LOW Medium High Impact on Overall System

35. Design Fallbacks 35

36. Project Organization • Overview: • Organizational Chart • Work Breakdown • Schedule • Budget 36

37. Organization 37

38. Work Breakdown 38

39. Schedule Summary Design Detail Fabrication and Verification Detail Management, Systems and Safety Detail 39

40. Budget Analysis • Senior Projects Fund • $ 4000 • Received • Engineering Excellence Fund • $ 1900 • Pending • Undergraduate Research Opportunity Program • $ 1000 • Tentative

41. References • Shevell, Richard S.  Fundamentals of Flight.  Prentice Hall. Upper Saddle River, NJ.  1989. • www.mpoweruk.com/lithiumS.htm • www.aurorra.co.uk/scorpion_tech_info.htm • www.dualsky.com/main.asp?mainset=24 • www.towerhobbies.com • www.hobby-lobby.com/index.htm • www.electrifly.com/motorsgears.html • www.all-battery.com/ • www.hardingenergy.com/techmanual.htm • Micropilot: www.micropilot.com • ieeexplore.ieee.org/iel5/9503/30160/01384699.pdf#search=%22RC%20glider%20payload%20capacity%22 • www.cds.caltech.edu/help/uploads/wiki/files/136/Aircraft_Pitch_Roll_Dynamicspdf#search=%22approximating%20aircraft%20roll%20rate%22 • www.atsrcplanes.com/hyperionchipmunk10e.htm • www.towerhobbies.com • en.wikipedia.org/wiki/Aspect_ratio_%28wing%29 • en.wikipedia.org/wiki/Wing_loading • www.hobby-lobby.com • www.electrifly.com • www.rcgroups.com/forums • www.rc-creations.com

42. Appendix 42

43. Imaging: Pitch/Yaw Rate Blur • Derivation of the Maximum Pitch/Yaw Rate Equation: Begin with the working definition for blur. Note from the diagram that: Substitute into the working definition for blur. Recall that we assumed: Substitute into the definition for blur to obtain the final equation

44. Imaging: Radial Velocity • The Maximum Radial Velocity Equation • Definitions • Range to Target (r), exposure time (t) • Length of Target (L) • Radial velocity: velocity component • directly toward center of target • Assumptions • Target is sufficiently far away that • Blur due to radial velocity is defined • as • Equation Target 1 Velocity (v) 0

45. Imaging: Geometry • Calculating the imager’s maximum radial velocity with respect to the target: Plot generated for 0.01 s exposure time • Max range = 100 m • If max blur = 1% • Max radial velocity = 100 m/s • If minimum realistic airspeed = 5 m/s • Minimum imaging range = 5 m

46. Imaging: Radial Blur • Derivation of the Maximum Radial Velocity Equation: Begin with the assumption: Take the derivative of both sides, remembering the chain rule, note the velocity term which results, and simplify. Recall the working definition of blur. Rearrange the equation and divide both sides by 0 to include the blur term. Solve for velocity.

47. Imaging: Roll Blur • The Maximum Roll Rate Equation: • Definitions • Range to Target (r) • Length of Target (L) • Downward angle of camera (d) • Roll angle of airplane between times t1 and t2 () • Assumptions • Target is sufficiently far away that  (equivalent to roll angle of airplane) Direction of roll target blur due to roll d range target length (L)

48. Imaging: Roll Blur • The Maximum Roll Rate Equation (cont): Using the old definition of blur:  Equation radius = (range)(sind) s = (radius)() target length (L) 1 = s / range 0

49. Imaging: Roll Blur • Calculating the camera’s maximum allowable roll rate: Plot generated for target length L = 1 m, exposure time t = 0.01 s, and downward camera angle d = 45º • Beyond 100 m range, maximum • rolling velocities are • small enough to rule out • This reinforces previous conclusions • concerning maximum range • Rolling velocities are not as driving • as pitch and yaw in finding • maximum imaging range • However, the blur gradient is quite • high and rolling velocities • need to be watched carefully

50. Imaging: Tangential Blur • Derivation of the maximum tangential velocity equation Recall the working definition for blur: Note that from the diagram: and Substitute into the definition for blur: Simplify to obtain the tangential velocity equation