PSA Bumper Material & Driving Over Power Cells

We found the type of material used for bumpers was critical in determining if power cells would be sucked under a drivetrain or simply pushed away

I would appreciate if other teams could replicate these results and comment on what fabrics they use.

@Andy_Baker if this is indeed verified it seems like it might be good to talk about on “Lunch with Andy” or elsewhere.

Here is a simple test video

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What was the gap between the bottom of the bumper and the ground?

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This is just a previous years robot. If memory serves the top of the bumper is at 7” so ~2” off the ground. I can double check Thursday

What fabric is the piece you tested? Is it the slick bumper material from AndyMark, or something else?

The robot has regular Andymark material and the material I place over it is the slick stuff you linked.

I would like another team that has actual bumpers made of this or another slick material to confirm

I don’t believe using the slick material is what solved this problem. I think the effect is more so due to the other material being loose and giving way to the ball when it rolls. If the material were fixed to the bumper (or was the bumper material), I really think a similar action would happen.

I’d love to see a test with 2 sets of bumpers, one with the normal and one with the slick, to get a better 1:1 test.

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It would also be interesting to see if the speed of the robot has a major effect with each of the bumper materials.

We did test different speeds and found no difference. I just videoed one run.

I will admit that it was a bit of a hack to lay the material over the bumper like that so I agree I would much rather see a test by a real robot bumper of that material.

I wonder if anyone at AM has done this test or has a bumper of that slick material. @Nick_Lawrence @Ruth_T

Since you have some of the material… how about stapling it to the top and bottom of the plywood and trying the test again? Easy to pull the staples out afterwards…

Unfortunately I went out of town on business right after testing this but I will test it Thursday night if we don’t get other results before then.

I really wanted a team with full bumpers of stuff to do it so they could test things like if it works well with the corners or maybe how a gap in the bumper has an effect or maybe even trying both of these test at 1" or 1.5" off the ground. Lots to test, still in the info gathering stage at this point.

Maybe the numbers on the bumper are what is sticking to the ball more than the fabric.

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We have bumpers made from both materials. I’ll see if we can do tests tonight and post the results.

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I think this topic will explode soon.
Getting game elements stuck under the robot is quite common thing that slows down the robot by around 10-30 seconds every time it happens (Can also cause fouls and even yellow cards if the Power Cell is damaged). If 28$ can fix this problem like the short video shows, teams would absolutely rush to get it.
If more tests will show that its critical to preventing the Power Cells from getting stuck it will be sold out in the blink of an eye

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Thanks for the heads-up. Looks like it might be a real pain to deal with.

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If you look at team 33, they seem to put some kind of plastic cover over their bumpers… not sure what material but that is another option

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I was just talking about this to some other people on our team. I remember seeing their bumpers covered in some clear plastic like material when I went to their pit at Detroit in 2018. I asked them about it and they told me why they did it but I can’t for the life of me remember what they said. I want to say it had something to do with making other teams bumpers not stick to their’s as much to provide some relief from defense? My memory really isn’t what it used to be anymore.

@Nick_Coussens could elaborate, but my understanding is they get the material from a local signage shop. (as-in they don’t coat their bumpers, the bumper material comes with a plasticy outer layer)

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yeah, I believe their reasoning was to be able to slide by opponents without causing much grip. I’m sure the similar would happen to the power cells… but gotta figure out what the material is first to test anything out. Also it seems that it has a very tight fit to the bumper so I’m assuming heat shrink or vacuum of some kind.

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@Nick_Coussens Just to satiate my curiosity, why do guys put it on the bumpers? Ever have any issues with inspection on the bumpers? I know they’re discussing using sail cloth lubricant on the Spectrum build thread and there were some questions as to where inspectors draw the line with bumper materials and what goes over them.

195 has used lubricant on their bumpers for quite a few years and it appears they haven’t had any issues with inspectors.

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