Roman Battisti Anthony Garcia Lori Sandberg Liz VanHoosen

Background Information First Lunar Lander used by Apollo 15 in 1971 For the past 17 years, NASA has held a competition to design, build and compete with a human powered moon buggy

Project Description Collapsible into a 4x4x4 foot box Maximum 15 foot turning radius Brakes must be on the vehicle Simulated electronics A 2 foot diameter antenna must be included A flag signifying its origin must be carried on vehicle All riders must sit 15 or more inches above the ground

Team Criteria Low center of gravity Lightweight-less than 180 pounds High Stability-no flipping Comfort and safety of the riders High top speed Maintain low assembly time

Design

Frame Design Preliminary frame design Strength in vertical direction

Improvements Needed Two major problems from previous year: Failure of central hinge Stability of back rider Other Concerns: Decrease weight Replacing worn/damaged parts

Hinge Design

Telescoping Back Wheels Finite Element Analysis Axle Hub Addition Wheel Hub

Impact Load Analysis Systems model developed in Matlab Assumed 600 pound mass k empirically measured Resulting force reactions found for step function

Visual Analysis Impact load reactions applied to system

Crank Lever Analysis Rider impact load applied to crank shaft lever Crank Shaft Cable Support Pin Attachments Main Frame

Steering A 15 foot turn radius is required to compete. An articulated steering system has been selected. Using the left figure we can solve for x:

Gear Analysis Shimano Nexus 8 speed Enclosed Cost: ~$260 Previously used Crank Sram 2 speed crank Previously used

Gear Analysis Cont. Front Gear Design Machine Design pg. 678 and 888 respectively Rear Gear Design

Brakes Disk Brake Analysis Brake force determined by assumed friction coefficient Brake force divided evenly for each wheel Brake force determined for each disk break (rotor)

Fabrication Tubing cutting and welding Nexus Replacement Hinge Assembly and welding Grinding Extending Back Axle Back Axle Assembly

Testing

Power Testing Dr. Mathew Bundle Velotron Ergometer

Off-Road Testing Rough terrain tests NASA specifications met Practice Assembly

Competition First Run: Assembly time: 9.88 seconds Raw run time: 3:56 Two penalties: +2:00 Hay bale “avoiding obstacle” Second Run: Crash and Burn!

Project Schedule Spring Semester Milestones MilestoneCompletion Date Frame FabricationFebruary 11, 2010 Hinge FabricationFebruary 1, 2010 Competition Registration DeadlineFebruary 1, 2010 Gear AssemblyMarch 1, 2010 Brake AssemblyMarch 1, 2010 Final AssemblyMarch 16, 2010 Testing and ImprovementsApril 2, 2010 CompetitionApril 8-10, 2010 Senior Design SymposiumApril 24, 2010

Budget SupplyEstimated CostActual CostsDifference Nexus Gear Box$265.00$ $19.50 Chromoly Steel tubing$800$258.70$ Axle$300$72.67$ Hinge$500$144.50$ Seat Belts$30$23.21$6.79 Other Supplies$122$ $ Plane Tickets$1,500$1, $ Shipping$700$650.00$50.00 Motel$426.00$425.20$0.80 Car$330.00$221.51$ Gas$37.00$6.00$31.00 Subtotal$5,010.00$4,340.32$669.68

Conclusions Performed as expected- design had both speed and adaptability No design Failures-no weld breaks, hinge and telescoping wheels survived actual impact loads Crash and Burn not due to design flaws Suggestions: Composite Frame Reduce weight of differential Replace center rotator cuff with suspension Adjust front Nexus angle and replace cranks Gears (number and ratio) specific to ability of riders

Special Thanks To: Dr. David Walrath Mr. Scott Morton Ken Battisti UW Engineering Machine Shop Pedal House Bike Shop 2009 Moon Buggy Team Wyoming NASA Space Grant Consortium Precision Air Cargo