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
Axle
Finite Element Analysis
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
.
.
..
Fy  k ( x0  xi )  b( x 0  xi )  m x0
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:
 26 ft 
x  180  2 tan 1 

L


Gear Analysis
 Shimano Nexus 8 speed
 Enclosed
 Cost: ~$260
 Previously used
 Crank
 Sram 2 speed crank
 Previously used
http://www.sheldonbrown.com/harris/shimano-nexus.html
Gear Analysis Cont.
Front Gear Design
 D3 
 n1 


D2  D1 
(GR) min  

 D4 
 n4 
N2 

 P 

sin 1 
D
 2
•Rear
Gear Design
D 
n 
D2  D1  3 GRmin  1 
 D4 
 n4 

N2 
 P
sin 1  
 D2 
Machine Design pg. 678 and 888 respectively
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)
F  mt
v
tb
F f  mt g
1 R
Fb  F w
4 Rr
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
Milestone
Completion Date
Frame Fabrication
February 11, 2010
Hinge Fabrication
February 1, 2010
Competition Registration Deadline
February 1, 2010
Gear Assembly
March 1, 2010
Brake Assembly
March 1, 2010
Final Assembly
March 16, 2010
Testing and Improvements
April 2, 2010
Competition
April 8-10, 2010
Senior Design Symposium
April 24, 2010
Budget
Supply
Nexus Gear Box
Chromoly Steel tubing
Axle
Hinge
Seat Belts
Other Supplies
Plane Tickets
Shipping
Motel
Car
Gas
Subtotal
Estimated Cost Actual Costs Difference
$265.00
$284.50
-$19.50
$800
$258.70
$541.30
$300
$72.67
$227.33
$500
$144.50
$355.50
$30
$23.21
$6.79
$122
$554.03
-$432.03
$1,500
$1,700.00
-$200.00
$700
$650.00
$50.00
$426.00
$425.20
$0.80
$330.00
$221.51
$108.49
$37.00
$6.00
$31.00
$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