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Learn the importance of robotics machine safety, drive train components, and maintenance. Understand various drive train configurations and key components in building a functional robot. Ensure safety and efficiency in your robotics projects.
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Importance of robotics Machine Safety Drive train Motor and parts Where to start Preventative maintenance Robot inspection Some ideas Overview
Teamwork and participation • Leadership • Science and technology • Solve problems Importance of robotics
Its important to keep shop clean Don’t be afraid to ask questions Always wear safety glasses Wear gloves when you can Doesn’t look right = ask General Safety
Secure bit • Make sure fits correctly • Don’t do too much • Wait till bit stops • Advanced: When changing belts, make sure unplugged • Fast = don’t touch Drill Press Safety
Game plan before Firm grip Take time Sharp = don’t touch Band Saw Safety
Correct set-up • Compensate for blade (measure) • Firm grip, stand back • Wait until blade stops Circular Saw Safety
Drive train segment Legend Drive base Wheel Ball caster Pivot point
Four Wheel Drive • Regular drive forward and back • Have to “skid” to turn • Simple • Bad maneuverability
Six Wheel Drive • Regular drive forward and back • Have to “skid” to turn • Relatively simple • Bad maneuverability
Six Wheel Drive contd. Center wheel lowered ¼ inch to provide good turning radius
Two Wheel-Two Caster Drive • Turns like shopping cart. Front “swings around” • Simple • Pretty good maneuverability
Harmonic Drive • Uses Omni-wheel (Above) to turn quickly in different directions with combinations of certain wheels going forward or backward • Four drive motors • Complicated • Good maneuverability
Harmonic Drive contd. Same idea but different configuration
Mecanum Drive • Basic four-wheel set-up with mecanum wheels and four drive motors • Each wheel goes diagonally one way so each needs to be a certain way • depending on spot (4 possibilities) • Similar to harmonic, change directions based on different wheels going different ways • Complicated • Great maneuverability • http://www.youtube.com/watch?v=npWA5AdZIGQ
Crab Drive • Uses wheels but has chain that connects and spins all wheels together • One motor to rotate each wheel, one drive motor per wheel • Very complicated • Great maneuverability • http://www.youtube.com/watch?v=q9uck-wRa_8
Rack and Pinion • Back wheels stationary, front wheels rotate to change direction • Four drive motors • Like a car • Very complicated • Great maneuverability
CIM • Most popular drive motor because it mates to Kit of Parts transmissions from ’05-present • Most powerful motor in the kit – 340W • Fisher Price • Usually come with 100:1 gearbox attached; gearbox has plastic gears • Most often replaced motor in FIRST Components: Suitable KOP Drive Motors
2+ Motors Per Side • Speed and torque are inversely related • Adding motors mitigate the effect of this – a drive train with 2+ motors per side can move a given load faster than a drive train with a single motor per side. • Not worth it! • 2 per side is really all you need Components
Friction Belts • Easily available • Cheap • Will slip under too much load • For some, it’s a feature. For some, it’s a nightmare. Belting
COTS gearboxes are fantastic alternatives for teams without heavy manufacturing capability • They require a bit of extra money, though. • Reliable • Large install-base with troubleshooting experience • A great investment Power Transmissions: Gearboxes
AndyMark Single Speed Gearbox • 12:1 ratio • Mimics previous Kit of Parts gearboxes • Accepts one or two motors • ~$100 ea. Power Transmission: Gearboxes
AndyMark 2-speed Transmissions • Low: 10.67:1; High 4.17:1 ratios • Available with pneumatic or servo powered shifting • Heavier than a custom design • Accepts one or two motors • Several output options • $330+ ea. Power Transmission: Gearboxes
Banebots Planetary Transmissions • Included in 2007 Kit of Parts • 12:1 Ratio • Pretty easy to put on • Versitile • ~$90 • Window motor Power Transmissions: Gearboxes
Conceptually plan, consider priorities • KISS = Keep it simple, stupid • RRRR = Reliability, Reparability, Relevance and Reasonability • Build test field, parts • Create CAD/paper design early • Order parts (Mcmaster-carr), prepare key members • Modular? • Build robot • Allow extra time for building, practice • Plan B bot? Where to start
A check over all systems before every match • Prevents major repairs from being needed • Allows for optimal performance • Make a check list • Check once the robot gets back • Again when robot is going to next match • Two person job Preventative Maintenance
Bolts should be checked for tightness • Chains taught • Battery charged • Check key features first • Gearboxes • All motor attachments • Problem spot that the team knows of Preventative maintenance checklist ex.
Mandatory • Do it early so the problems can be fixed • No sharp edges • Team number and school name visible • Electrical wires safe • Keep record of purchases, parts • Go to inspection with bumpers off, wear gloves and have bill of materials • Design award: Team member to talk to judges Robot Inspection
2013: Frisbee launcher • http://www.youtube.com/watch?v=8KVK8svZzbI • http://www.youtube.com/watch?v=tLHyVlUO5jo Ideas – how to play this year’s game
Importance of robotics Machine Safety Drive train Motor and parts Where to start Preventative maintenance Robot inspection Some ideas Summary