Vertical Take-off and Landing Electric Aircraft

1. Vertical Take-off and Landing Electric Aircraft Villanova University College of Engineering 2007 - 2008 Senior Design Project

2. The Team Dustin Getz, CpE microcontroller hardware-software interface Christopher Pepper, EE ECE leader control circuits Karl Recktenwald, ME frame fabrication Richard Zemsky, ME ME leader overall design

3. Project Goal • Goal: • To develop a scale prototype of an electric-powered aircraft • Vertical take-off and landing • No exposed main rotor • Computer-facilitated control • Scope: • Develop a suitable aircraft configuration • Design the control system • Motivation: • Personal, small-scale transport • Efficiency and environmental friendliness

4. Focus points • Feasibility • weight, power, money • Design • mechanical hardware selection and configuration • electrical hardware selection and configuration • Control • environment sensors • algorithms and simulation

5. Overall Design (continued)

6. Overall Design (continued)

7. Overall Design (continued)

8. Overall Design (continued)

9. Overall Design Inspiration for aircraft configuration http://www.marian-aldenhoevel.de/modelle/BeechStarship.jpg

10. Mass 1.80 kg Weight 17.66 N Desired Acceleration 0.80 m/s2 Required Net Thrust 1.44 N Total Required Thrust 19.10 N Specifications After 5 sec: height = 10 m Ftot = Fhover + Faccel

11. Feasibility Selecting suitable motors and fans: Duct size Air velocity Maximum Thrust Maximum Power Selected Duct Diameter: 5.6 cm http://www.hobby-lobby.com/ductfan.htm

12. Feasibility (continued) For Duct Diameter: 5.6 cm Dotted lines denote the projected ducted fan operating point Calculations validate fan specs. Thrust per fan > 20 ozf. (5.56 N) Total Thrust > 22.24 N x 4 fans

13. y z x Design Features Overview: 4 ducted fans 3 thrust locations Redirect thrust to enable vertical and conventional flight modes Automatic stabilization of the craft via on-board sensors and programmed control laws fully stable in x-z plane

14. Design (continued) • Ducted fans: • 4 fans with DC brushless motors • 3 points of thrust (stability) • 2 front fans on either side of fuselage • 2 rear fans side by side = 2 + 1 http://www.hobby-lobby.com/ductfan.htm http://www.hobby-lobby.com/littlescreamers.htm

15. First Flight Attempt: Response Rear Duct Design • Two 45° pipes • Rotate 2nd pipe through 180° Vertical Mode Horizontal Mode

16. Design (continued) Vertical Flight Mode

17. Design (continued) Horizontal Flight Mode

18. ρcf = 1384 kg/m3 σcf = 827.4 MPa ρAl = 2699 kg/m3 2518 psi 3.663 psi σAl = 379.2 MPa Structural Analysis • Frame: • Weight = 244.5 g • Carbon fiber, epoxy • Structural analysis performed ρ ≡ density σ≡ tensile strength

19. Electrical: Circuit Diagram

20. Inclinometer 6 Signals Electrical: Block Diagram Receiver Power x4 x4 MCU Voltage Controllers 3 Signals 2 Unique + 1 Shared Fan Motors 2 Signals Aircraft Power Range Sensor Receiver 5 Signals x5 6 Signals Servomotor Power Servomotors Lithium Polymer Batteries x5 Transmitter

21. Electrical: Circuit Design • Motor controllers (x4) • –Jeti Advance PLUS • – Rated for 18 Amp • Batteries (x5) • – Thunder Power "Pro Lite" Lithium Polymer Packs • – 4 Cell 1320 mAh • Radio Controller • – OPTIC 6: Programmable Radio Control System • – 6 Channels • – Multiple Flight Modes

22. Electrical: Circuit Connections • Speed 400 Polarized Connectors • – Batteries • – Motor Controllers • – Power lines Power Line Ring Terminals • 1-pin Female to Female Jumper • – Inclinometer • – Range Sensor • – Peripheral power line • – Motor Controllers • Molex Connections • – Motor Controllers • – Motors

23. First Flight Attempt • Craft was too heavy • Failed to create positive lift • Responses: • Disassemble the aircraft and audit the weight • Measure motor thrust

24. 1847g 2123g Initial Final Weight Reduction • Drilled holes in braces ……………………….. -37g • Cut and sanded rear duct pipes …………….. -146g • Replaced metal bolts with nylon bolts ………-18g • Replaced circuit plate ………………………-75g 276g (13%) reduction Reductions

25. Fan Performance Test Setup Front Fan Rear Fan + Duct Hall Effect Ammeter Counter-balance weights Force Gauge Digital Scale

26. Fan Performance: Results • Quantify thrust as function of power input • Front fan • Rear fan with 90° duct

27. Second Flight Attempt

28. Human control • Raw: Human controls motor thrust • Human • responsible for balance • corrects for environmental influences • Intelligent: Human controls craft velocity • Computer • responsible for balance • automatically corrects environmental influence

29. Intelligent control Microcontroller Pilot command Combined intelligent control handheld controller DC motor control lines Environment awareness Servo motor control lines orientation altitude

30. Digital motor control • How do you control a motor with a computer? • dsPIC 30f, 30MHz clock • 200kHz AD conversion • pulse width measurement and generation in hardware • floating point arithmetic • 68 I/O pins for sensor interfaces Coded percentage of maximum thrust Power supplied to DC motor Pulse Code Modulation

31. Pulse Code Modulation • Width of pulse linearly related to thrust percentage 10% thrust 90% thrust

32. Sensors • Awareness of height Polaroid sonic transducer, driven by SensComp range-finding module 4.5 V Voltage response to tilt • Awareness of inclination (roll, pitch) VTI SCA100T 0.5 V -30 +30

33. Altitude control • Use throttle to control velocity • Behaves like critically damped spring: transitions as fast as possible, without ringing Up, neutral Up, down, neutral Throttle command Thrust response Altitude response

34. Sum of Torques: Desired result: M = Mass Matrix θ = Angle u = Control Torque k, c = PD Constants Resulting Control Torque: Electrical: Control Laws • Developed equations of motion with help of Dr. Ashrafiuon via LaGrangian derivation approach. • Will use zero-dynamic control to balance platform

35. Simulation of Pitch Stability • Noise of maximum amplitude 4N•m and initial angle of 60° • Control torque magnitude limited to .8 N•m – motor limitations • Maximum angular displacement is 2 degrees after initial correction Control Torque .8 N•m -.8 N•m 2.0s 0.0s Noise Torque Angular Displacement 60° 10 N•m -10 N•m 0° 2.0s 0.0s 0.0s 2.0s

36. Funding Keystone Innovation Zone $2000 Engineering Alumni Society $800 VU Mechanical Engineering Department $500 VU Electrical & Computer Engineering Department $500 Hobby Lobby Parts Donation Funding

37. Conclusions • Scalability: • Non-linear • Problems scaling up electric motors (weight) • Configuration: • 3 thrust locations • 4 motors can reduce to 3 • 1 large rear motor, 2 smaller forward motors • Controllability: • The system is stable, robust, and controllable

38. Funding Keystone Innovation Zone Engineering Alumni Society Mechanical Engineering Department Electrical & Computer Engineering Department Advisors Dr. Chun (ME) and Dr. Singh (ECE) Consultants Dr. Marston – Total Design Dr. Ashrafiuon – Controls Mr. Harris – Microcontroller Mr. Pluscauskis – Structural Analysis Villanova Technicians Acknowledgments

39. Questions?