Team John Deere Final Presentation

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Team John DeereFinal Presentation

• Josh Ebeling
• Jamari Haynes
• James June
• Mike Reno
• Ben Spivey
• Gary Twedt

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Outline

• Project Outline and Goals
• Existing and New Designs
• Analysis and Design Selection
• Prototype and Final Design
• Prototype Testing
• Conclusion

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Project Goals

• Modification of the Gator Utility Vehicle for
  handicapped accessibility
• Limited or no operational interference
• Ergonomic and easy to use for all potential users
• Kit-ready final design

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Project Constraints

• Must operate within existing layout of the Gator
  Utility Vehicle
• Must allow sufficient space for driver and
  passenger to sit comfortably
• Must allow full operation with both new controls
  and pedal controls
• Must be no significant modifications or
  alterations to install device

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Description of Desired Motion

• Brake Motion normal motion of the brake pedal
  depression causes brake lever to raise up
• Gas Motion normal motion of gas pedal
  depression causes gas activator to be pulled down
• Two motions must be combined for accessibility
  with one hand

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Existing Technology and Market

• Current industry standard and most prevalent
  design is the Braun 3500 Hand Control
• Easily integrated for a variety of car sizes and
  types however, difficult for user to install
• Less than desirable required dexterity and force
  to operate
• Overall design concept desirable, application of
  product for specific use with the Gator not
  desirable

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Initial Designs and Comparisons

• Initial design concepts included direct
  depression of both pedals by device (Designs 1
  2)
• One design concept included direct depression of
  only one pedal by the device, with the other
  pedal pulled down through the motion of a cable
  (Design 3)

Design 2
Design 1
Design 3
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Final Design - Initial Selection

• In order to take advantage of unique Gator design
  layout, a straight bar extending out from
  underneath the dashboard was selected
• Rough prototype of design worked well
• Analysis necessary to determine force needed to
  depress brake

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Engineering Analysis

• Final Force 50 lbs at a displacement of 30º
• Pros Design allows for monotonically increasing
  force
• Cons 50 lbs of force may be too much for users

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Final Design Second Iteration

• L-Bar designed to give mechanical advantage to
  the user, allowing rotation of the Brake Lever
  with less force than straight bar
• Pros Force well within desirable range
• Cons Force is not monotonically increasing,
  contact between L-Bar and Brake Lever a point of
  failure, more space taken up by support, harder
  to install

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Engineering Analysis Second Iteration

• Maximum Force 35 lbs at Maximum Displacement of
  20º
• Final Force 28 lbs at Final Displacement of 33º
• Decreasing force at the end of the
  force-displacement curve is extremely undesirable
  disrupts the design more than the 50 lbs of
  maximum force for the straight bar
• Further alteration of design possible curving
  bar

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Final Design Third Iteration

• L-Bar still lowers Brake Lever, with less
  user-supplied force than straight bar
• Curved bar designed to raise force necessary at
  end of force-displacement curve
• Pros Force well within desirable range
• Cons Force is still not monotonically
  increasing, contact between L-Bar and Brake Lever
  a point of failure, more space taken up by
  support, harder to install

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Engineering Analysis Third Iteration

• Maximum Force 31 lbs at Maximum Displacement of
  22º
• Final Force 30 lbs at Final Displacement of 34º
• Decreasing force at the end of the
  force-displacement curve still present even
  leveling of force displacement curve is
  undesirable according to Industrial Design group
  members
• Straight bar provides best curve at small cost

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Final Design Selection

• Force-displacement problems ultimately resolved
  in the selection of the straight-bar design over
  the L-bar design
• Monotonically increasing force-displacement curve
  vastly more important to ergonomics than minor
  strength concerns

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Final Design Composition

• Final design comprised of three main subsections
• Brake handle
• Provides the user with mechanical advantage with
  which to operate brake
• Brake clamp
• Stabilizes brake handle
• Gas clamp
• Activates gas through tension on cable

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Final Design and Prototype Comparison

• Final design matches prototype in nearly all ways
  however, there are two key differences
• Brake Clamp modified for ease of machining at the
  expense of stability of the prototype
• Range of motion of the gas handle is less than
  was desired

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Clamps and Stabilizations

• Machined clamp connects to brake pedal lever with
  hose clamp
• Provides significantly less lateral and
  rotational stability than the machined part for
  the Final Design
• Stability issues solved with rudimentary
  cross-tied support

Supports
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Demonstration of Motion - Brake
Video of brake motion
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Demonstration of Motion - Gas
Video of gas motion
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Acceleration Comparison

• Lack of full play on the gas handle results in an
  inability to achieve full acceleration with use
  of handle only a prototype flaw
• Results for comparison
• Pedal average point-to-point travel time 4.84 s
• Handle average point-to-point travel time 7.82 s

Acceleration comparison videos
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Braking Comparison

• Brake handle actual provides easier braking than
  pedals because of decreased necessary force
• Results for comparison
• Pedal average point-to-point travel time 1.755 s
• Handle average point-to-point travel time 1.635 s

Braking comparison videos
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Possible Improvements

• Improvements to the project are mainly limited to
  stricter adherence of the handle to the Final
  Design as drawn
• Development of detailed product installation
  manual only possible last step

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Conclusion

• In conclusion, group design met all project
  goals, including
• Operating within existing layout of the Gator
  Utility Vehicle
• Allowing sufficient space for driver and
  passenger to sit comfortably
• Allowing full operation with both new controls
  and pedal controls
• All with no significant modifications or
  alterations to install device
• Design considered a success

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Questions?