Best Drivetrain options

[Ginger Power]

Originally Posted by Donut

This works well, but as Eric said get used to driving it like a shopping cart. My team did this in 07 and 08 and you're guaranteed not to have a problem turning.

We didn't have any trouble turning, but our belts did tend to slip a lot more than with other drives we've ran. I want to say that has something to do with the non central center of turn. Just a guess though. Otherwise great drivetrain that a driver can good with quickly. I would be suprised if 4607 didn't run it again this year. Although slide is appealing too for reasons already covered in this thread.

[jeremylee]

Originally Posted by JorgeReyes

What about a 4wd with the rear wheels being traction wheels and the front ones being omnis

We did this drive for 2013. It drove smooth and turned really well. It does have a tendacy to overshoot the turn more though as you have more rotational inertia and very little scrub. We have been considering it again for this year.

Here's a video in action:
http://m.youtube.com/watch?v=QD04NZHPLmc

[lamk]

We have been driving an off season 6WD square Versachassis with 2 speed gearbox, 4 inches wheel with drop center. Strapped a bunch of totes in various position to the chassis with some clamped on metal bar to see how it drives. The drive team did not like the way how a 6 tote stack lean back and forth. 3 tote stack on the chassis not a big deal.
We remove the center wheel and the turning wasn't too bad and obviously no more leaning back and forth.
We also drove the 4 wheel configuration over the scoring area, bottom out and gouge the brand new built scoring area.
6" traction and omni wheel is on it's way. We will try all omni wheel or 2 omni and 2 traction. We are leaning towards 2 front traction and 2 rear omni but will have to see.
Also one really need to find a way to grab all the totes stacked on your drive train if you wanna move around quickly. We have some really "entertaining" video of "flying totes" when our driver try to turn or accelerate /decelerate too fast. Can't defies the law of physics.

[mrnoble]

We have reconfigured a couple off season projects to the needs of this game for testing, and here's what we know:

• mecanum 6" does really well over the bump, surprisingly so.
• 6" Colson in front, omni in back does great too. we think it drives a bit like street racing, so its currently "drift drive" for us, though "mullet drive" is gaining.
• we cant decide between the two yet, so we are building both and running them through drive practice. we will let the drivers and coach decide.

I'm sure swerve is awesome. Next year, we will make that our off-season project. We have no experience with "H" style slide, so it's off the table too.

Hope that info is helpful.

[Abhishek R]

Originally Posted by JorgeReyes

What about a 4wd with the rear wheels being traction wheels and the front ones being omnis

IIRC, 1625 Winnovation used this system in 2014 (and I think in previous year(s) as well). It was one of my favorite robots; the spins were amazing, yet they still had all the versatility to be able to play effective defense as well as escape it.

Here's a video of them on Einstein. If you can't see the numbers, they are the primary scorer on the red alliance. https://www.youtube.com/watch?v=xWPjs8zn9FI

[Shu]

Originally Posted by JorgeReyes

What about a 4wd with the rear wheels being traction wheels and the front ones being omnis

How about the reverse with omnis in the rear and traction wheels in the front? Is there any advantage for one over the other?

We converted an old kitbot over the weekend to this configuration. It seemed to pivot about the front inside wheel. We had several team members drive it and they didn't appear to have any issues controlling it.

[IronicDeadBird]

Going to have to go ahead and say strafing is a must but if you can't strafe you should at least make a chariot design with casters...

[pfreivald]

"Must"s are exceedingly rare in FRC competitions.

[IronicDeadBird]

Originally Posted by pfreivald

"Must"s are exceedingly rare in FRC competitions.

Yeah I should have phrased myself better. Depending upon level of your team and comfort if you have the ability to do omni-directional movement then it is very valuable. Not to say that the arguments against omni-directional are non existent.