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.
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.
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!
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.
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.
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).
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.)
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.
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
It turns great, never had a single problem. Turning easily was actually one of the reasons we went with this design. Ex 1Ex 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.
It’s not nearly as cool as a swerve, but we did not use pneumatic wheels, nor treads. We beefed up the usual 6WD to a 10WD, featuring three different wheels (2 2015 KoP wheels, 4 2010 KoP wheels, and 4 8" plaction wheels with pebbletop tread). They were staggered into four lines because they were too big to put ahead of each other. Here’s a pic of the drive train before we installed any manipulators. The pebbletop does most of the work on the carpet and the slicks do a fair share of the work getting over the defenses.
Not the best picture but here is what we did on Team 5508. It is 2 drive trains. One with treads and one with 4 wheel (2omnis and 2 traction). It worked good and only broke a tread once.
A pretty good picture of all our wheels + chain. It did pretty well for us, and I was amazed at how easy it was to turn the wheels by hand on an unpowered robot. Base team did a great job of chaining it. essentially 6WD, center drop, but each side had an additional 4 raised wheels to help with rockwall/moat/ramparts. We used the vex wheels in a 1.5" configuration so they couldn’t get stuck in the rough terrain.
1x1x.125 aluminum tubing, welded, powder coated. We have a sponsor that can do welding for us so we were able to get by with 1/8" aluminum.
Also, this powder coated frame became our practice bot because we didn’t come up with a rig for keeping axle holes aligned during the welding process =(. It was late in the season so we tried a fix by match drilling some plates and drilling out the axle holes on the inside runner for our practice bot (I’m surprised, but I can’t find a good picture of it). Since it worked, we spray painted our frame originally intended as a practice bot frame and implemented the fix on the powdercoated frame during/after bag and tag. I liked to refer to our comp bot frame as the Ugly Duckling.
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