Weirdest Drive Trains

A true swank drive:

4143 in 2016. Swerve except each wheel is actually a loop of tank tread

Twerve or Swank drive definitely win this one.

That “twerve” was insanely awesome to see in person. I doubt there will be more than a half dozen more attempts at it in the next decade, probably all of the by 4143

There are some really cool(and weird) drive trains so far, so to keep it going here is 456’s “Siege Drive” from this year. Tracks were actually used, the Colson wheels are only on the one side to show versatility.


8W tank with pneumatic tires, no drop. Outside four wheels (on over-center linkages) lifted up, and ball casters dropped down to prevent rocking. Powered by CIMs in servo-shifted Dewalt XRP drill gearboxes.

Also, surprised that nobody has brought up 6w swerves yet. 100% of them have made it to Einstein.

How about WildStang in 2004?

Not so wild now, but wild at the time: How about the first use of omnis in FRC, on 67, vs the first use of swerve in FRC, on 47?

Just checking… the criteria is “weird”, not “good”, right?

If so I humbly submit for your consideration, team 1346 from 2005.

We had learned from our rookie year that four wheel drive doesn’t make for a great tank steer system… so to improve turning we added pneumatically actuated casters to the rear of the robot. When we wanted to turn we’d drop the casters, lifting our rear wheels off the ground by an inch or so.

And leaving us at the mercy of two tiny little casters on a narrower wheel base, often while holding a 10 pound tetra ten feet in the air.

About the only good thing I can say about the drivetrain was that it helped us get on a Discovery channel advertisement when – with a tetra high in the air, and the casters deployed – we were gently bumped by our good friends (and temporary opponents) from 1241. “We saw your robot on TV!” friends would comment. “Yeah, demonstrating what happens when you mix a narrow wheelbase with a high CoG!” I’d reply. But really, it was cool to be on Discovery, regardless of whether we were getting our butts kicked or not.

It’s hard to see in this photo, but if you look between the rear wheels you’ll see one of the little casters poking down.

So I submit a four wheel drive system, with pneumatic skyway wheels on the front, hard rubber wheels (with zip ties to improve traction, I think) on the back, and pneumatically actuated casters to make the whole thing more tippy and random when turning. I’m pretty sure FIRST has never seen anything else quite like it, and that it has never been repeated. All for good reason.

A bit of a shame, though, as the robot did have a few good features, and winning the Creativity award for (in part) our plywood beam arm set us on to a future of intentionally designing with baltic birch and making a bit of a name four ourselves in “doing plywood robots right” over the next few years.

But what a terrible drivetrain… what WERE we thinking???


Seconded. I remember being absolutely baffled by that very drive train at the Buckeye Regional in 2005.

5464 came up with another modified rhino track robot.

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RIP to 276’s rotary walker. The 2003 version (the biggest and most terrifying) liked to climb other robots and rip their wiring out from above.

Also 276 (allegedly, Dean has a picture of this robot hanging somewhere in his residence):

The team I graduated from still has this beauty together! In 2013 a team member put the C-Rio system in and had it driving around :slight_smile:

Can it turn?

Surprisingly yes! Better than I thought!

2495’s “lobster drive” this season was two complete drivetrains perpendicular to each other, with one of them mounted to a frame that raised/lowered with pneumatics. You can drop down the second drivetrain to strafe on non Omni/mechanum wheels.

Lots of obvious drawbacks but it was cool to see, and even won the creativity award at MAR

Must be geared pretty low… Most drive trains I’ve seen with wheels that big have severe difficulties trying to scrub across carpet, especially with a longer rather than a wider wheel base!

Probably the king of weird drive trains. You know you’ve made it when you cause a rule change (no attaching metal to the carpet).

Turning scrub doesn’t have a lot to do with wheel size, but in this situation, when the wheels are this huge it actually shortens the wheelbase as the contact patch is farther in from the center than it would be with smaller wheels (mounted farther out). So that robot would have an easier time turning than you’d expect.

Bigger wheels tend to be pneumatic wheels though, which have their own set of turning problems, so this could be part of what you see. Improperly geared big wheel drivetrains will also be too fast to apply good torque.

Yes, exactly – the big wheels require significantly lower gearing than small wheels, and I’ve seen a nontrivial number of teams incorrectly anticipate the problem.

We know what we’re good at, and it never hurts to be immovable… We’ve made our fair share of enemies from bots trying to ram us and destroying themselves while doing so🤷🏼‍♂️