Mentors Workshop Mechanical Sub-System Mark McLeod Team 358 Festo/Hauppauge H.S.

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Mentors WorkshopMechanical Sub-SystemMark
McLeodTeam 358Festo/Hauppauge H.S.

• For
• Inspiration and
• Recognition of
• Science and
• Technology

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Objectives

• FIRST Rules Restrictions
• Official Suppliers Other Sources
• Basics/Components
• Design Notes
• Potential Problems
• Keeping Students Busy
• Typical Schedule

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FIRST Rules Restrictions

• FIRST motors restricted in quantity and type
• Any suppliers of other components like gears,
  sprockets, chain, wheels
• No materials restriction other than nothing
  dangerous
• 3500 limit (2005) on all additional parts
  including outside labor and other sub-systems
• Must pass event inspection volunteers and all
  that implies

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Official Suppliers

• Official Suppliers
• www.innovationfirst.com/
• www.ifirobotics.com
• Other Sources
• www.andymark.biz
• www.spi.com/
• www.wmberg.com/
• www.sdp-si.com/
• www.bostongear.com
• www.picdesign.com
• www.mcmaster.com
• www.martinsprocket.com
• www.servocity.com

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Basic Components

• Motors Drill, Atwood/CIM, Fisher Price, Van
  door, Window, Globe
• Gears and/or sprockets, key stock
• Wheels (hard, pneumatic, trick, casters, skids)
• Chassis
• Manipulators, arms, special purpose devices

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Design Notes

• Kit drivetrain (kickoff video)
• Alternate drivetrains (direct drive, gears,
  sprocket/chain)
• Manipulators
• Motors (variety, specs)
• Fabrication
• Design considerations
• How fast and robust?
• Steering method
• Protect wheels and drive mechanism
• Pre-built transmissions
• Tradeoffs between motors and pneumatics

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Potential Problems

• Poor gearing
• Overheating/stressing motors
• Breakers blowing
• Unusual 12v battery drain
• Misaligned drive shafts/drivetrains
• Additional friction from operating on field
  carpet
• Unbalanced or high center-of-gravity causing tips
• Entanglement or other risk to other robots
• Safety hazard to field crew, spectators, or
  players
• Over weight speed holes in chassis, gears,
  etc.

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Keeping Students Busy

• Calculate various gear to sprocket to wheel
  ratios
• Build hubs for wheels
• Practice assembling and disassembling drivetrain
  components
• Test and monitor drive motor current draw

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Typical Electronics Schedule

• September thru December
• Develop basic skills
• January thru March
• Six week build period
• Robot design space for electronics and wire
  runs
• Actuator requirements
• Designing and testing solutions
• Resolve physical layout
• Integrating solutions with electrical/control
  system/pneumatics
• Regional event
• Inspection

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Further Information

• www.chiefdelphi.com -- team technical forums
• http//firstrobotics.uwaterloo.ca/resources.php
  -- At the FIRST Mechanism Library, you can find
  pictures of all sorts of designs sorted by
  mechanism. Current categories include Arms,
  Drivetrains, Elevators, Frames, Gearboxes,
  Grippers, Joints, Rollers and Wheels.

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Workshop Materials

• Gears (with and w/o speed holes)
• Sprockets/35 chain
• Motors
• Motor mounts/pillow blocks
• KOP motor mount/hardware and gears