Linear Actuator

1
Moonavators Fall Semester Design Review
Team Members Caitlin Flynn Michael Mahlum Craig
Craviotto Shane Duff Hans Leidenfrost Jake Conn
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Table of Contents

• Linear Actuator
• Base
• Arm/Elbow Joint
• Future Plan

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Linear Actuator

• Previous Issues
• Rack and gear meshing slop
• Uniform linear movement through bearings
• Drive motor needs replacement
• Improvement Ideas
• Mount second gear to face of primary gear
• Replace linear roller bearings with sleeve
  bushings
• Replace motor with higher torque version

4
Gears/ Bushings
Fasten new gear to primary gear to increase
contact area of gear to linear rack
Chose sleeve bushing to increase surface contact
on rack to increase stability Will reduce
twisting and bending slop Eliminate linear ball
bearing for smoother motion
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Motor
Current motor is inopperable 2561 Motor ordered
to replace the 641 motor previously in
place. Higher Torque, but lower speed
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Base Setup
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Drive Gear
Current Base Setup 1/8 slop from lazy susan
POT
8
Drive Gear
New Base Setup
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Direct Drive Motor
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Arm/Elbow Problems

• 1/8in arms
• Arm twists too much
• Not rigid enough assembly
• Elbow helical gears
• Creates lateral loads on arm
• Low gear ratio results in small torque increases
• Exposed gearing picks up debris

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Quick Fix Ideas

• Channel Arm Idea
• Lighter, strong, resists torsion, but hard to
  make
• Square Tube Idea
• Heavier, strong, and easier to make

12
New Arm 1st iteration
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Progress so far
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Test Assembly Chipping Rock
Goal Replace the linear actuator with a more
powerful assembly to break rock.
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Future Milestones

• 1st Iteration redesign Nov. 28thth
• Interim Report Fall Semester Dec. 9th
• Final Design Decision Dec. 2008
• Senior Design Expo May 2008