Different Drivetrains
 

It seems this year, most people went with either a 6wd/8wd pneumatic or tank treads to get around everything. Show off what your team did differently and why!

Team 3072 went with pneumatic tires in the center, with omnis on the corners in a 6wd configuration. We also used Bimba pistons and custom designed plates to give our omni wheels suspension. We can raise and lower the wheels to give us better angles at things, and to help with shooting. We decided that this would give our robot an advantage, considering how high the RW is, not getting stuck in the moat, and helping absorb impact when ramming into things.

Re: Different Drivetrains
 

This year, our team went with a pneumatic-tired swerve drive. It certainly presented a lot of engineering challenges to make, but it also offers us a lot of advantages in competition -- for example, the use of an omnidirectional drive allows us to easily align in front of the goal with vision tracking, and the pneumatic tires mean we don't sacrifice any traction or defense-crossing ability. It also opens up a lot of new possibilities for defending/avoiding defense.

https://www.youtube.com/watch?v=SZ9sYcAYBzo

Our team is very proud of how successful we were in pulling off such a unique drivetrain, and we hope to showcase more of its capabilities at champs tomorrow!

Re: Different Drivetrains
 

That's a rather interesting drivetrain.

Did your bot turn easily with the grippy wheels in the center? Did it move quickly? Did you have to worry about the omnis taking the force of hitting the obstacles?

I feel like I'm missing an obvious design cue with this. My first thought was "they should've put the pneumatic wheels on the ends and the omni in the center so it could absorb the hits while still being able to turn (with the raising and lowering of the front and rear)", then I wondered if rotation would still be feasible with the friction.

Still, very innovative design. I like it!

Answering the question, we went with the standard-ish AndyMark Rhino module treads. We're definitely making our own drivetrain next year.

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Just three wheels for us...

http://www.thebluealliance.com/team/525

Re: Different Drivetrains
 

I don't have a picture but we have a total 6 wheels 2 six inch wheels in the front and 4 eight inch wheels in the middle and back so the 6 inch wheels don't touch anything until we go over a defense and then they make it easier to get over the defense.

Re: Different Drivetrains
 

What was the benefit of using only three wheels? It looks like a very interesting concept!

Re: Different Drivetrains
 

It looks to be 3 pneumatic wheels, two bidirectional and one omnidirectional, similar to a swerve drive. I wonder how it would perform with two omnidirectional wheels on the front instead of one (eg. rectangle instead of triangle).

Re: Different Drivetrains
 

It crosses the defenses rather easily. We can mostly crawl over them - don't need to ram and fly over. The single wheel end is a swerve module - we use that to aim. When on the batter, we turn it sideways to use as a park brake. It will drive over one or two boulders easily (it will get stuck if we try to drive over three boulders.)

Re: Different Drivetrains
 

Triwheels, since we wanted to do something different
https://www.thebluealliance.com/team/5870/2016

Re: Different Drivetrains
 

I don't have a picture, and I wish I did, but there was a team at Orange County with 4 wheels, looked to be about 10"-12" range. They weren't necessarily round, though... They were squishy and spongey--might have been some sort of filter in another use case. That team went after a driving defense, they'd go right over it. Can't remember the number.

Re: Different Drivetrains
 

By chance, do you mean 3953? If you do, they have a good picture of their wheels on TBA.

Re: Different Drivetrains
 

That's them.

We had two 10" pneumatic wheels in the front, two 6" colsons in the middle, and two 8" omnis in the back. We originally had 6 10" pneumatic wheels then found that if the center wheel was smaller, it went over defenses much more easily, but with 4 3" wide pneumatic wheels it couldn't turn so we ended up putting omnis in the back and it goes over defenses wonderfully

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There was a team (5183) at Kettering #1 that had tracks off of a snowblower for their drivetrain.

https://www.flickr.com/photos/131241...7666413129205/

Re: Different Drivetrains
 

It turns great, never had a single problem. Turning easily was actually one of the reasons we went with this design. Ex 1 Ex 2 Just a couple matches from Hampton Roads to showcase. (Our shooter was shut down due to bumper rules, or we would be doing more than breaching. :( )

This thing was actually pretty quick, way quicker than the mecanum drive we had last year.

We never had a problem other than one of the axles on the pneumatic wheels bent in Blacksburg. (Weird, huh?) That was probably the worst that happened. We had the pressure set wrong in Hampton Roads, so we were really bouncy and had to take it slow, but since we had the pistons taking most of the shock, they never had any problems. We inspected them after every match to make sure they weren't cracked or broken.

I really enjoyed the challenge, and it won us the Innovation in Control Award in Hampton. I think custom frames and drivetrains will be in our team for years now.