FRC 95 The Grasshoppers 2020 Build Thread

I’m a little surprised you didnt record the time it took to reach pressure.
I feel that would be an important metric and would change the number of pumps you have in order to reach it in a useful amount of time

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Anecdotally it’s a few seconds, with the majority of the pressure differential achieved in the first second. It’s fast enough that it’s never struck us as a particular concern.

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That’s a fair point and one good way of looking at it.

We considered it from a total electrical draw perspective - the electrical system (battery) struggles to provide enough power for 6x 300+W motors generally. So while we could add more and more pumps, if we’re loading up our drive motors and more than two pump motors we are at an extreme risk of brownout, so it would likely not be useful to have more than two.

Build season is finite, so we focused our efforts to making a good ground seal and optimizing the flow for two pumps.

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This has brabham fan car written all over it… maybe with a little less horsepower though.
Wonder how carpet/floor construction plays into this. Generating a seal on a hard surface is one thing, but on a porous surface is another.

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Has this been tried in previous seasons? At first glance this looks like a violation of G26:

G26. Be careful what you interact with. ROBOTS and OPERATOR CONSOLES are prohibited from the following actions with regards to interaction with ARENA elements. Items A – C exclude POWER CELLS, HANDLE, and the ALLIANCE’S CONTROL PANEL. Item G excludes the HANDLE.
A. Grabbing
B. Grasping
C. Attaching (including the use of hook tape to anchor to the FIELD carpet and excluding use of the PLAYER STATION hook-and-loop tape, plugging in to the provided power outlet, and plugging the provided Ethernet cable into the OPERATOR CONSOLE)
D. Deforming
E. Becoming Entangled
F. Damaging
G. Suspending from
Violation: MATCH will not start until the situation is corrected. If during a MATCH, TECH FOUL. If during a MATCH and longer than momentary or repeated, YELLOW CARD. If offense is via a ROBOT and the Head REFEREE determines that further damage is likely to occur, offending ROBOT will be DISABLED. Corrective action (such as eliminating sharp edges, removing the damaging MECHANISM, and/or re-Inspection) may be required before the ROBOT will be allowed to compete in subsequent MATCHES.

There is no attaching to the field going on. They are simply increasing their normal force.

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I have to say that that this is not all black and white. I’d love to see if this is deemed legal…

I don’t see how any interpretation of [G26] or ruling against the current Q&A question could invalidate the vacuum without also invalidating wheels with a non-smooth surface (such as patterned pneumatic tire tread, blue nitrile tread, roughtop tread, etc).

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I’d also be worried about G26-D, “deforming” the carpet. Still, 95 continues to awe me with their team and robot designs.

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We have been using ours an havent had issues but now I know they can exist, I’ll keep a close eye on the coupling.

When one works out a FBD this is essentially all that is happening. We are removing air from under the robot at a rate that reduces ambient pressure under the robot. If you picked up the robot, moved it, spun it, whatever, it won’t drag the carpet or any field element with it.

@mrnoble thanks for your kind words! In our testing there was no detectable deformation or movement of the carpet. It doesn’t ‘suck the carpet up’ in any way. Our bellypan is clear plastic to check for this.

@ferrari77 I would expect exactly that link from someone with your UN. :slight_smile:

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Have you checked what happens when you run these pumps over the gaffers tape markings on carpet?

Yes and no. It does not appear to disturb any of the carpet tape on our practice area. It is not exactly the same gaffers tape and our carpet is pretty old and tired though…

Are you generating a vacuum without actually sealing to the ground? This is a super interesting concept!

We are working on a skirt that does conform to the ground. But the carpet is highly porous, so it is a battle of pulling air through the carpet weave.

If you can line up with the 3" wide barriers, you would have a solid surface to stick.

Definite sarcasm :smiley:

I’m psyched to see it in action though, even if I’m personally skeptical.
Try it on a laminate floor at some point just for fun?

Is that sarcasm?

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Are you sarcasm?

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