Suggestion on low skirt for robot

I understand that low skirt can help prevent disks from getting under the wheels. At the same time, I also saw some robots getting stuck if disks somewhere get under the low skirt, and basically dead for the game. Any suggestion on low skirt design and how low it should be optimally? Thanks.

Low skirts help a lot with discs getting pushed into you, although you have to put guards on fron and back of drive too, so you drive up on discs. My team has done this, and has had no issue getting stuck on discs

The bot’s wheels will drive over disc/discs quite well. It’s the chassis that gets hung. Invert your thinking… raise the chassis… no more hanging problems. Can also drive over the corner things.

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We use 4” standard wheels. Not sure how to raise the chassis.

How low is the skirt? Right now our wheel guard is made of long screws with spacers, which is about 1/8” above the floor. It is very hard to escape if it gets over the disks. We are thinking about using a C-Channel under the frame, which is about 1/2” above the tile (As a reference the disk is 3/4” thick. )

Practically every robot with a skirt at state got discs stuck under it.

To raise the chassis… if using a 1x2/1x3 c channel, put the bearings in the LOWEST holes, not the center. That’s all you need.

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I guess I understand what you mean now, but that is not the problem I observed so far. We have no problem driving over disks even without raising the chassis. However, if in the autonomous mode the wheels do run over disks, in particular during turning, it is uncertain where it will end up with. Another issues is that if a disk gets under the chassis, it can be counted as being in possession. That is why we want to prevent disks from getting under the robot, in particular the wheels. Thanks

Program auton to avoid discs. As far as driving over… that doesn’t count as possession. The disc must turn w/ the bot for it to fall under that classification.

I think that is a general rule – disc must move with bot to equal possession. However, preventing another team from access to a disc by having it below your bot (high centered or not) is also possession. Not sure of the Q&A and too tired to look it up.

Yeah… I always forget about the ‘prevent access to game elements’ section. Then again… vex always manages to make things harder than they need to be. I feel like this year’s bot need to have roomba-style flippers that keep discs from getting under it.

Usually, skirts refer to two plates on the sides of the robot, but in this case, you probably want them on the front and back. That is what we do:
Screen Shot 2023-04-04 at 8.15.54 AM
On the back of our robot we have a low bar to protect disks from getting under. This has worked very well for us on the past 3 robots, and also allows you to have a hard stop for wedges.

On the front of our robot, our intake is the width of our robot, and very low to the ground.

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our team had very low skirts that could hinge. during most of the game they would just stay down to prevent thing from getting into the drivetrain but when going over the barrier it would move up and out of the way so that it did not get stuck. We also did not have issues with getting stuck on disks due to front and back disk proofing. its a decent solution if you cant raise the drivetrain and managed to get it done with just a few zip ties connecting the slide / skirt to the c channel.

if you want a low skirt, you can attach a piece of L channel to the bottom of the drivetrain c channel. this will prevent discs from entering the sides of your robot.

here is how we did ours.


ben !

20 characters of love <3

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Thank you Benn. It looks very nice!

Thanks for sharing the design. We will try that.

Benn, a question. If the L channel gets on a disk for any reason, is it easy to get off for you? Thanks.

Don’t make it too big, don’t make it too small. Simple as that.
I recommend making it on all sides, making it low, but not so that it would EVER touch the ground. If you have problems with discs getting stuck under it, maybe add a bent layer of metal or plastic to keep it out. It could cause the discs to slip back out of the underside of the bot.

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Also, I just completely made this up. The idea came into my head just now. Probably not good. Worth a shot, wanted to throw in my two cents.

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If you decided to put a polycarbonate piece on top of this, would that count as decoration or would it become part of the allowance

Our robot was pretty heavy, and all the areas of the robot were low. We never got stuck on discs