FRC Drive Trains

[Starke]

Originally Posted by cmrnpizzo14

This hopefully is a simple question. I'm trying to look into drive trains a little bit for our team this year and I was just wondering if people could give a quick description of their favorite ones from previous years.

Thanks!

Just as a heads up: FRC Designs has a range of different drive trains to check out.

FRC Designs: www.frc-designs.com
FRC Designs Drives Page: www.frc-designs.com/drives.html

[AdamHeard]

Originally Posted by Chris is me

Kitbot on Steroids with Colsons. There's nothing better in terms of effort to reward ratio. You might never have to do maintenance on it.

Wouldn't using the kop wheels be equally reliable in terms of wear, but require less cost and effort?

[BrendanB]

Originally Posted by AdamHeard

Wouldn't using the kop wheels be equally reliable in terms of wear, but require less cost and effort?

Colsons are nice but I agree that if you are just going with a kitbot, why use colsons? The new Higrip wheels are superior to previous FIRST wheels but investing in Colsons is $180 for hubs and wheels. As a rookie or low resource team I'd rather invest that $180 into other parts of my robot considering I'm already given reliable/comparable drivetrain.

Maybe the future kitbot on steriods is upgrading to supershifters?

[Chris is me]

Originally Posted by AdamHeard

Wouldn't using the kop wheels be equally reliable in terms of wear, but require less cost and effort?

You're certainly right, especially with the new HiGrip wheels that are in a similar ballpark to Colsons. I mentioned Colsons to contrast with the common suggestion to upgrade to a treaded wheel, as tread does add some (arguably negligible) regular maintenance to the system.

[Alan Anderson]

Originally Posted by AdamHeard

Wouldn't using the kop wheels be equally reliable in terms of wear, but require less cost and effort?

I've never seen a Colson wheel throw a tread or experience a broken spoke.

[JesseK]

It seems to me that the OP had a specific drive train in mind given his constraints before the first reply was made. Resources for learning about this type of drive train exist in several places -- only the specific teams numbers do not. Yet even with pictures of specific teams' drive trains, the OP won't have a full picture. That type is the 6WD Skid Steer. You want to use "KISS" as a mantra? There's no need to even look at Octocanum (FRC525 & others), Slide Drive (lots of VEX teams), Crab/Swerve Drive (FRC1717, FRC118, so many others), Twitch Drive (FRC1565 in 2008, FRC1885 in 2009), Ball Drive (FRC45 a long time ago), Mecanum Drive, Omni Drive, Car Steering Variants (FRC34/FRC1629 in 2008) or NonaDrive (FRC148).

What the OP needs are tips & tricks to make a simple drive train successful without having to go through the painful experience of learning everything himself (though this list isn't comprehensive):

• Motor-Gearbox burn-in -- 1.) Grease the gearbox. 2.) Run the motor and gearbox together for 10-20 minutes with the wheels off the ground 3.) Clean the gearbox. Do not fret over metal shavings, just clean them out 4.) Re-grease the gearbox
• Sprocket-Sprocket Alignment -- sprockets with a connection chain should be coplanar (i.e. exactly parallel and precisely transversely aligned)
• Sprocket-Wheel alignment -- The sprockets that connect to a wheel should be exactly parallel to the face of the wheel. Do not use individual plastic spacers/washers to space a sprocket off a wheel (though the solid AM spacer is fine)
• Bearing-Wheel alignment -- When wheel (without connecting chain) is free-spun on the axle that connects it to the frame, there should be NO wobble on the wheel structure (tread wobble is fine for the most part).
• Chain Tension -- Use at least 120-degrees of chain wrap around each sprocket for #25 chain or 90-degrees for #35 chain. Chain should flex roughly 3% (of the sprocket-sprocket distance) up/down -- i.e. it shouldn't be so rigid that there's no vertical flex in the chain.
• Do not settle for the KOP gear ratios if those ratios don't satisfy how your team wants to play the game. With a stock KOP drive train, the easiest/cheapest way to adjust gear ratio is to change the sprocket located on the gearbox output shaft.

I'm sure there are other tips that I'm forgetting at the moment.