Best Drivetrain

[Richard Wallace]

Originally Posted by EricH

The size has changed AT LEAST three times that I know of. Something small, 36" x 36", 36" x 30", and now 38" x 28".

I really hope someone from GDC is reading this. IMHO, we are overdue for a new robot footprint. I'd like to see it get smaller, maybe 35" x 25" or something similar.

A smaller footprint would encourage lighter robots. It might also encourage finesse (read: manueverability and control), rather than raw traction, as a distinguishing feature of FIRST's most capable machines.

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I agree the best drivetrain is the one that gets your robot in position for a scoring attempt, or to stop an opponent's scoring attempt, or to support your ally's scoring attempt, and right quick. Which type that is will always depend on game design.

931's last five drivetrains were:

2004 -- custom 4WD with four independent motors, two 9" pneumatics, two 9" custom dual omniwheels. Not finished early enough to perfect control, but reasonably effective.

2005 -- 6WD with #35 chain and 4" Colson wheels, powered by two kit transmissions (thanks, Paul -- those were incredibly tough and easy to use). We unfortunately put a great drivetrain on a questionable chassis, made from 8020 with poorly reinforced corner joints.

2006 -- custom holonomic. We built our own ominwheels and gearboxes, and a custom chassis made from aluminum channel with gusset plates and lots of 1/4-20 clinch nuts. A work of art that won a design award at IRI, but not particularly effective for keeping our ball shooter on target.

2007 -- 6WD with kit gearboxes on a kitbot chassis, #35 chain to the kitwheels on the center and #25 chain to the AM aluminum omniwheels on the corners. Very reliable and manueverable, resulting in a good offensive robot when the defense was light. We were easy to turn when defended heavily.

2008 -- custom live axle 8WD with #35 chain to the four center wheels, and #25 chain to the 1/8" raised corner wheels. AM Supershifters with one CIM per side. Very controllable, resulting a consistent 4 line hybrid mode and good speed during teleo.

Our custom drivetrains in '04, '06, and '08 were all fun to build and we learned a lot. But my overall takeaway is this: if it looks feasible to use a 6WD kitbot chassis next year, I'll be pushing the team to do that.

931 won regional Chairman's Awards in both of the years that we used 6WD with kit gearboxes. Coincidence? Or does spending less time fiddling with custom drivetrains allow us more time for other aspects of our program?