LABET Low Altitude Balloon Experiments in Technology

1. LABETLow Altitude Balloon Experiments in Technology CPR E 491 ENGR 466

2. Team Introduction ENGR 466 Team Brian Walker Richard George CPR E 491 Team Mike Svendsen Steve Towey

3. Client Introduction Client Iowa State University Space Systems and Controls Lab (SSCL) Advisor Matthew Nelson

4. Overview • Client Statement of Needs • Functional Requirements • Non-Functional Requirements • Deliverables • Project Decomposition into Subsystems • Design Concepts • Testing and Evaluation • Work Plan

5. Client Statement of Need • The SSCL has worked on several iterations of its LABET platform which is a blimp platform used for both research and for outreach events.  Currently, all of these have been limited to indoor use only which does limit their functionality for some research based projects.  The need is to have an outdoor blimp platform capable of carrying a small payload and able to navigate in calm to light winds

6. Operating Environment • Outdoor usage • Maneuverable in winds up to 10 mph. • Operate in temperatures between -20 and 100 F. • Operate in humidity up to 90%

7. Functional Requirements • Vertical lift capability up to 500 feet • Wireless control/interface up to 1500 feet • Additional payload lift of 7 ounces minimum • System fly time of no less then 20 minutes • Fly and maneuver in up to 10 mph • Balloon lift potential between 80-90% entire system weight • GPS and pressure sensor to determine position

8. Non-Functional Requirements • Durable and reusable design • Controlled via computer interface • Determine position via computer interface

9. Project Deliverables • Complete balloon system meeting requirements • Operating manuals • Design documentation

10. Decomposition into Subsystems

11. Decomposition into Subsystems Software: Includes embedded LABET software, base station communication, and GUI. Propulsion Systems: Includes vertical and horizontal thrust motors, propellers, ESC’s, and main battery use. Balloon System: Provides majority of lift of the entire system while providing stability. Load Frame: Support for control / sensor systems and payload, while providing balance weight. Electronics: Includes micro-controller, wireless communication, and all sensors.

12. Work Breakdown

13. Design Concepts

14. Balloon System Design

15. Balloon Design Breakdown Hybrid Latex Blimp System Envelope • 1 mil plastic sheeting • Seamed to form the blimp shape Balloons • Two individual 48” latex balloons • Provides majority of entire system lift • Easily replaced and interchangeable Stiffeners • Creates a rigid blimp shape in conjunction with balloons • Foam core creates rigid yet light and inexpensive solution Weight Distributor • Foam core bars • Distributes weight of frame to envelope and balloons • Seals envelope shut when connected to frame

16. Final Design Decisions Assembly • Open seam prior to connection • Stiffeners assembled inside envelope • Balloons placed and blown inside envelope Visual Presence • Alternating color tip to determine front • SSCL and LABET symbols for added visual Benefits • Breaks down to manageable sizes • Envelope easily repaired • Parts interchangeable and replaceable

17. Load Frame Research Previous LABET Systems • Load Frame Design • Gen. III – Duel Fan Control • Gen. IV – Direct Balloon Attachment • Gen. V – Propeller Mounting • Material Usage • Material Selection • Weight • Strength • Durability • Cost

18. Load Frame Design

19. Load Frame Design Breakdown Cross Foam Core Load Frame Foam Core Structure • Rigid material yet light and inexpensive • Cross design to minimize material Wooden Motor Mounts • Bass wood for rigidness and strength • Built in sheer bracing which connects to frame Propeller Shrouds • Protects propellers from interference • Provides some thrust funneling System Box • Contains/protects battery and circuits • Weight supported by cross structure • Removable/Replaceable to meet payload changes

20. Final Design Decisions Structure • Cross frame design • Spaced separation to maximize strength • Distributes weight through balloon connection Visual Presence • Minimal in design for weight and look • Hides wires and electronics from view Benefits • Material is durable and light for size • Materials locally and inexpensively obtained • Direct connection to balloon system

21. Propulsion – Design Process • Weight Constraints • 24 ounces Battery Life Calculations Thrust Calculations

22. Propulsion • Ducted Fans vs. Propellers • Brushless Motors vs. Brushed Motors

23. Propulsion – Design Selections • Thrust • Battery Life

24. Electronics – Design Process • Compile list of sensors • GPS, Rate Gyroscope, Pressure Sensor, Fuel Gauge, Digital Compass • RF module • Previous LABETs success with XBee

25. Electronics – Design Process • PIC vs. Atmel • Selecting PIC Processor • Operating Voltage – 5.5V • USART – 2 • I2C Bus • Timer Counters – 5 • Program Memory – 48 KB

26. Electronics – Block Diagram

27. Software – Design Process

28. Software – Base Station • Development Language and Platform • C++ on Linux • C++ on Windows • Java • LabVIEW

29. Base Station – Frontend

30. Base Station- Backend

31. Software - LABET

32. Structural Testing Balloon System • Seam stress tests • Lift potential test • Assembly/Balloon fill test Load Frame • Drop test • Motor mount sheer test • Assembly/Balloon fill test

33. Electronics Testing Hardware • Simple test programs Software • Communication tests • GUI interaction tests • Ground tests

34. Risks • Hybrid balloon system • Encountering unforeseen setbacks • Little experience with RC equipment

35. Costs/Resources

36. Task Breakdown

37. Current Status • Load frame complete • Balloon complete • Propulsion system integrated • Electronics selected and ordered

38. Spring Semester Gantt Chart

39. Questions