Moonbuggy ME Capstone Design Project SP 2006

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MoonbuggyME Capstone Design ProjectSP 2006

• By Chris Haire
• Brandin Ray
• Beth DeShong
• Andrew Wall
• Vinay Prasad

Mentor Dr. Jie Chen Dr. S. Sivakrishnan
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Reason For Design

• Improve Safety
• Increase Stability
• Enhance Maneuverability
• Enhance Mobility

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Customer Requirements

• Must fit within 48 Cube in Stowed Configuration
• Light-Weight Design
• Ride Height at least 15
• Human Power
• Ease of Assembly
• 4 Width when Assembled
• 30 Degree Incline without Tipping
• Ensure Safety of Riders

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Engineering Requirements

• Light-Weight Design
• Even Weight Distribution
• Maximize Tipping Angle
• 20 Turning Radius
• Frame Stiffness
• Short Assembly Time
• Ground Clearance

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Engineering Targets

• Buggy weight less than 200 lbs.
• 46 Width
• 15 Turning Radius
• Tipping Angle more than 30 degrees
• 1st Gear Ratio of 51 for Climbing
• 50/50 Distribution (front to back) (side to
  side)
• Max 5mm Deflection at Folding Point.
• 9 Seconds Assembly Time
• Minimum 15 Rider Clearance

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Product Development - Frame

• Light weight design
• Back to back seating
• Center pivot makes for easy folding
• Increased frame stiffness

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Product Development - Subsystems

• Drivetrain
• 2-wheel drive
• Configured for back to back riders
• Chain does not disengage when stowed
• Rear Suspension
• Redistribute forces to avoid single-point failure
• Improve off-road and cornering capabilities

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Final Product
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Demonstration
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Product Evaluation - Specifications

• Buggy Weight (without riders) 158 ¼ lbs.
• Width 44 ¾ (rear)
• Ground Clearance 8
• Rider Clearance 22

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Product Evaluation Specifications cont.

• Weight Distribution - Front/Rear
• Weight Distribution - Left/Right

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Product Evaluation - Performance

• Top Speed - 13 1 mph (winner, 11 mph)
• Turning Radius 6 ft
• Lateral Acceleration 0.74 0.10 gs
• (10 mph 9 ft turning radius at speed)
• Gear Ratio 0.441
• Climb 35 Without Tipping (Climb / Traverse)
• Deflection at Folding Point 0.12 mm
• Assembly Time 28s

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Engineering Targets vs. Product Performance

• Targets Successfully Met
• Weight is 41.75 lb under
• Width is 1 ¼ under
• Turning radius is 9 ft under
• Tipping angle over 35 degrees
• Deflection is 0.12 mm compared to target of 5 mm.
• Weight distribution within 10
• 7 over minimum rider clearance

• Improvements Needed for Targets
• Does not meet lowest gear ratio requirement
• Assembly time 24 seconds over initial target

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Conclusion

• Major Accomplishments
• Designed and fabricated frame
• Designed and fabricated rear suspension
• Incorporated a 2-wheel drive design and unique
  drive train configuration
• Fabricated and assembled completely new moonbuggy
  design at minimum cost
• Built a safe, stable and rugged moonbuggy that
  can serve as a solid base for future teams