pic: 1502 Union Drive

We’re bringing back our old school Union drive this year, with a colson twist!

If I may ask a respectful question: What particular advantage does a drivebase like this give your robot/team that other drive bases cannot provide?

That being said, it does looks well machined and thought out. I am sure that whatever advantages you foresaw will absolutely be evident 1502.

From the match videos I saw it looked like it was pretty hard to drive.

What were the decisions that lead to this drive choice?

It gives greater control over the placement of cubes, as the center of rotation is on the same axis as our lifter. The powered omni’s are very useful for positioning cubes. There is a fancy modified 4 bar that mounts to the front that’s pretty close to a strait line mechanism. With the whole setup, it drives like a fork lift. With the battery over the omni’s for counterweight, it’s a very stable thing.

Starting height is 32" and can extend to over 7’. The students did a very good job making it happen. As this is a teaser, you don’t get to see the triple climb mechanism or arm until later. :stuck_out_tongue:

They also implemented some pid tuning into the omni’s for auto impact resistance/correction, and it is now extremely hard to kick it of course.

That was before the colson wheel change and some major technical difficulties. Aka tripping breakers continuously and a randomly restarting robo rio from a faulty power distribution board. It’s much better now!

Is there any reason this couldn’t have been accomplished with a simple 4-wheel tank drive with omnis in the back? You’d have a bit more forward traction, fewer gearboxes, and smaller drive footprint, while keeping the same kind of control scheme, I would think.

Also, are you actually running only 2x CIMs (one on each side) on your competition bot? That might be contributing to your breakers tripping.

The other problem was that a gear change happened that shouldn’t have, and it didn’t get noticed till later. They had it geared for 16 fps!!!

how well does the omni wheel go over the power strip bump. Is it pushed (first wheel to go over) or pulled ( last wheel to go over) the power strip bump. Do you have any concerns with the wheel its self or the shaft to the wheel bending, I love the design the power cord strip would be my only concern.

The only problem with it was the old rough top tread didn’t have enough traction on the platform so it would tend to hung up a bit there. If it does get hung up on the cord, it’s from going to slow, and a simple flick of the steering gets it over. I think it only works because they are the 8 inch wheels. Any smaller and they probably wouldn’t go so well. It will likely break the Omni before bending the steel shaft.

I’m glad to see there are still innovative drivetrains that make even seasoned FRC veterans ask, “What???”

Like many replies here, I’m curious about how it performs and whether there is any advantage over more traditional solutions, but I’m glad to see that you’re trying new stuff and that you’ll stick to your guns regardless of a few doubters like me.

Hope it works great… and if you get a chance to post a video of it demonstrating some awesomeness, I’d love to see it!


We’ve done this type of drive on and off since 2006 and it always seems to come back. With a good driver that understands weight transfer, it does defense well while maintaining smoothness. If I don’t get a good video before the week 3 event just look for us at Lincoln. Drive team should be able to showcase it by then. I knew what was going to happen with this post because it happens at every competition. :smiley: