Alpha 6.5: The Great Moonbuggy Race 2006

1. Alpha 6.5: The Great Moonbuggy Race 2006 Russell Alberts Scott Coll Haison Nguyen Jason Zaloudek Sponsored by: CBU Department of Mechanical Engineering Faculty Advisors: Dr. Bernard Beard, Ph.D. Dr. Paul Shiue, Ph.D. March 18th, 2006

2. Presentation Overview • Race specifics • Design requirements • Vehicle improvements • Testing overview • Final design evaluation

3. The Great Moonbuggy Race • Entrants must “design a vehicle that addresses a series of engineering problems similar to problems faced by the original Moonbuggy team.” • Vehicles will be human powered and carry two drivers over a half-mile of simulated lunar terrain including "craters", rocks, "lava" ridges, inclines and "lunar" soil.

4. The Course

5. Competition rules provide the design requirements of the vehicle Must fit inside 4’ cube in “stowed” configuration No wider than 4’ in operational configuration Maximum turning radius of 15’ Minimum passenger ground clearance of 15” Drivers must carry vehicle 20’ unassisted Must be equipped with simulated mission equipment Design Requirements

6. Alpha 6 Lunar Roving Vehicle • Designed as proof-of-concept vehicle to navigate the lunar surface • A human powered vehicle (HPV) • Competed successfully in NASA’s 2005 Great Moonbuggy Race

7. Alpha 6.5 Lunar Roving Vehicle • Redesign of the Alpha 6 LRV • Eliminate previous critical design failures • Transmission mounting failure • Difficult steering design • Compete in the 2006 Great Moonbuggy Race

8. Major Design Tasks • Steering control • Steering links redesigned • New driver controls improve ease of operation • Drivetrain • Stronger design and built to eliminate structural failure • Durability of vehicle drive train improved • Race performance • Suspension system stiffened to improve obstacle maneuverability

9. Overview of Previous Suspension System • The front and rear suspension are both independent systems • Shock and spring combination used for dampening • Front assembly made of Chromoly steel and aluminum • Upper and lower control arm (A-arm) mounts spindle • Heim joints and ball joints link suspension components • Steering system utilized pushrod mechanism

10. Redesign of Front Suspension • Geometry components of the system reanalyzed • Camber and toe-out • Understeer • Affects of loading • Improve suspension system stability • Unsteady hubs • Poor dampening shocks • Improve steering control for improved driver interface • Front assembly made of 4130 Chromoly steel and aluminum

11. Coilovers Improve Race Performance • Front suspension stiffened to improve vehicle ability to negotiate obstacles Spring Constant • Old: 228 lbf/in • New: 976 lbf/in

12. Design of Wheel Hub • New design is composed of three components • Hub is to be sleeved with stainless steel, which serves as the bearing • New hub provides ride stability and precision • Solid one-piece design provides high structural integrity

13. Analysis of Front Hub Static load multiplied by a factor of 3

14. New Steering System • Old system uses a rotating T-plate connected to solid links and a lever • Wire steering creates a system that uses cables instead of rods or shafts • steering system utilizes Heim joints on all linkages • Heim joints are multidirectional and more precise • Implementing steering wheel provides more intuitive control • Flexible wire cables adapt easily to folding frame

15. Additional Modifications • New driveshafts manufactured due to wear and tear of old parts • CNC-machined out of heat treated stainless steel and TIG welded

16. Additional Modifications Continued • Previous cantilever support for seats show signs of deflection • Modified circular cross section and moment arm designed to increase safety factor

17. Drive Train Reconstructed for Improved Durability • 21 speed transmission • Low Gear • Torque: 357 ft lb • Speed: 2.0 mph • High Gear • Torque: 19 ft lb • Speed: 16.5 mph • Critical drive train failure prevented completion of 1 heat in last year’s race • Transmission mounting plate redesigned • Expected loading: 88.5 ft lb

18. Alpha 6.5 will be more extensively tested than past entries Improved testing sequence provides: Additional time for redesign Reconstruction before competition Testing will explore Vehicle frame strength Maximum sustainable and operational speeds Control during obstacle negotiation Test Plan

19. Design Verification – The “Drop” Test • LRV designed to survive a 12” drop while fully loaded • Vehicle will be subjected to a fall of equivalent force • Verifies frame designed and manufactured strength • Verifies vehicle meets race guidelines for driver ground clearance

20. Design Verification – Operational Speed Test • LRV designed with a maximum sustainable speed of 16 mph • Design based on average human capability • Must be verified with selected drivers • Maximum sustained speed over smooth terrain • Operational speed over rough terrain

21. Design Verification – Extreme Situations • The “Stair Flight” Test • Verify vehicle control and strength during a trip down CBU’s library front staircase • The “Sand Pit” Test • Will determine ability of vehicle to maneuver out of the CBU volleyball court • The “Lazy Driver” Test • Test transmission mounting

22. Design Verification - Race • Ultimate success will be determined by performance in the 13th Annual Great Moonbuggy • Moonbuggy designed to give drivers the best opportunity to win • Race is held on April 8, 2006 at U.S. Space and Rocket Center in Huntsville • Come support us; you will be glad you did

23. Project Goals Remaining • Complete assembly of Alpha 6.5 transmission • Test vehicle • Increase driver familiarity with vehicle operation under race conditions • Win 2006 Great Moonbuggy Race

24. Questions