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Purpose of this Presentation Drivetrain Selection o Types of drivetrains o Types of wheels o Drivetrain mechanics o Best drivetrain for your team o Maintenance

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Ideal Drivetrain Gets your robot where it needs to be, when it needs to be there Is robust and reliable Can push/pull objects and other robots Meets your strategy goals Fits with the game Can be built with your resources Rarely needs maintenance Can be fixed quickly

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Basics Know your resources Decide after kickoff: Speed, power, shifting, mobility Use the most powerful motors on drivetrain Dont drive of your robot WEIGH IT DOWN! Break it early Give software team TIME to work Give drivers TIME to drive

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Wheel Types: Traction Standard wheels with varying amounts of traction, stength and weight AndyMark KOP VEX Pro AndyMark Plaction AndyMark Pneumatic

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Wheel Type: Holomonic Special Wheels that allow the robot to achieve Holomonic motion Mecanum Omni Crab Module

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Caster, Omni, Slide Driven Wheel + Easy to design + Easy to build + Light weight + Inexpensive + Agile - Not much power - Will not do well on ramps - Easily turned Motor(s) Drivetrain Types: 2 Wheel Drive

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Chain or belt Driven Wheels + Easy to design + Easy to build + Inexpensive + Powerful + Sturdy and stable - Not agile - Turning is difficult Motor(s) Driven Wheels Drivetrain Types: 4 Wheel Drive 2 Gearboxes

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Drive Wheels + Easy to design + Easy to build + Powerful + Sturdy and stable + Many options: Mecanum, traction - Heavy - Costly Motor(s) Drive Wheels Motor(s) Drivetrain Types: 4 Wheel Drive 4 Gearboxes

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Gearbox + Easy to design + Easy to build + Powerful + Stable + Agile* - Heavy ** - Expensive ** ** - depending on wheel type *2 ways to be agile 1.Lower contact point on center wheel 2.Omni wheels on front or back or both This is very common in FRC + simple + easy + fast and powerful + agile Drivetrain Types: 6 Wheel Drive 2 Gearboxes Check out 1114s Kitbot on Steroids Simbotics.org Resources Kitbot en esteroides

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Gearbox + Powerful + VERY Stable - NOT AGILE - HEAVY - Inefficient - EXPENSIVE - Hard to maintain For turning, lower the contact point on center of track wheel Sole benefit: Ability to go over things Will NOT push more than a well- controlled 6wd Drivetrain Types: Tank Treads 2 Gearboxes

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Tank vs. Holomonic Tank Drive 2 Degrees of Freedom Rotation Forward-back Motion Holomonic Drive 3 Degrees of Freedom Rotation Forward-back Motion Side-side Motion

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4 wheel drive or 3 wheel drive + Immediate Turning + Simple Control 4 wheel independent - No brake - Minimal pushing power - Jittery ride, unless w/ dualies - Incline difficulty Drivetrain Type: Killough

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+ Simple mechanisms + Immediate turn + Simple control 4 wheel independent - Minimal brake - Minimal pushing power - Should have a suspension - Difficulty on inclines Drivetrain Type: Mecanum

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http://www.youtube.com/watch?v=xgTJcm9EVnE Team 1346 Mechanum Drive

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> Each wheel rotates to steer + High-traction wheels + No friction losses in wheel-floor interface + Ability to push or hold position + Simple wheels - Complex system to control and program - Mechanical and control issues - Difficult to drive - Wheel turning delay Drivetrain Type: Crab/Swerve

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368s Crab Drive in 2010 http://www.youtube.com/watch?v=q9uck-wRa_8

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Game dependent Determined by wheel size and gear ratios Controllable top speed: 15 ft/sec Average 1-speed rate: 9 ft/sec Good pushing speed: 4-5 ft/sec Drivetrain Top Speeds

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Center of Gravity (CG) o Robot mass is represented at one point o Mobility increases when Cg is low and centered o High parts = light weight o Low parts = heavy (within reason) Which is more Stable?

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Gearboxes/Transmissions Gear ratio determines top speed and motor load Single Speed and Shifting options CIMple Box shipped in 2011 KOP 1 or 2 CIMs per gearbox 2011 4 CIMs allowed Must be greased to reduce friction

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Belts + Dont Stretch + Can reach far - Need to buy in custom sizes

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Chain Selection #25 + Lightweight + Easy to install + Smaller - Easy to derail - "Steches" over time #35 + Allows for slop + Minimal "stretching" + Heavy duty applications - More weight

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Working with Chains Tensioning o Critical to keep robot from throwing chains o Must be accessible and easily adjustable o Does not need to be used on ALL chains but should be on drive systems

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Look at other Designs! Competitions chiefdelphi.com Team websites YouTube thebluealliance.com

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Presented by: Paul Hines John Hines Drive Types + Wheel Pictures www.AndyMark.com (FRC Supplier) Swerve Drive Revolution Custom Frame www.team221.com (FRC Supplier) Check out 1114s Kitbot on Steroids Simbotics.org Resources Kitbot en esteroides