Mechantronics 433 Design Project: The Automated Bug Treadmill

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Mechantronics 433 Design ProjectThe Automated
Bug Treadmill

• Owen Loh
• Erik Cruz

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Project Overview

• Control spherical treadmill using automated
  visual feedback in MATLAB

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Project Components

• Localization techniques using MATLAB image
  acquisition toolbox
• Motor selection
• Motor control using basic computer interface
• Use localization to create command signal

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Control motor rotation accordingly
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Localization in MATLAB

• Capture image from webcam
• Find bug
• Compute offsets from center to determine proper
  control output
• Timing?

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Drive Mechanism - Ideal

• Drive wheels placed orthogonally at the major
  diameter
• No wheel slip required
• Equation of motion

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Similar Existing Mechanism

• T. Murphy, R. Webster III, and A. Okamura,
  Design and Performance of a Two-Dimensional
  Tactile Slip Display, Proceedings of
  EuroHaptics, Munich, Germany, 2004.
• 2 DOF haptic display
• Two drive motors turn a delrin sphere
• Slip angle is difficult to characterize
• Used 1 DOF system in actual experiments
• Compensate with control

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Drive Mechanism - Offset

• Drive wheels set below major diameter by angle F
• Opposite drive wheel must slip
• Equation of motion

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Future Considerations

• Motor selection
• Motor control
• MATLAB
• Real-time OS
• Sphere selection
• Diameter, mass, moment, surface roughness
• Insect
• Speed, acceleration, size
• Camera placement

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Spheres

• Want light and smooth
• Transparent?
• Available materials
• Rubber (1-8)
• Polypropylene (1-6, hollow, translucent)
• Polyurethane (1-8)
• Wood (1-6)