My FRC students came up with using velcro on the cargo intake wheels. Despite careful reading of the rules and searches on this forum and Reddit, I can’t find any mention of this. Surely this needs to be banned immediately. A quick test showed it to be brilliant for catching the ball, it also instantly degrades the fuzz on the ball. If lots of teams did this, the balls would be like a pompom within a few matches.
Our current prototype is using 4 inch mechanum wheels on the outside of the horizontal intake bar with compliant foam wheels in the middle.
I would recommend that any team thinking of using hook-and-loop that might damage cargo should read G301, R201, and R202 carefully. In general, field crew (including referees and inspectors) notice robots that regularly damage arena elements and will require it to be corrected. It may be that it’s possible to use such a mechanism without damage, in which case I don’t know offhand of a rule against it, but if it is in fact damaging as you say then the existing don’t-damage-stuff rules probably cover it.
G301 is one to consider. While it gives exception to A-C for CARGO, it doesn’t give an exception to F.
You can attach to (including hook/loop as mentioned in C) but cannot damage. If this is resulting in damage, you’re likely to see the problem resolved partially through this rule.
Additionally, you’re either concerned about how frequently CARGO will need to be swapped out or how that degradation impacts the intake’s design. The first would be resolved through guidance that damaging the balls with velcro is occurring and G301 should be enforced here. The latter would be resolved by you not being able to rely on the velcro and finding a design that’s more sustainable.
Both have a resolution, assuming what’s taking place is degrading enough to impact game play.
Is the fuzz on the ball that critical to your design? I’ve seen multiple videos of prototype intakes with Velcro and none of the seem to rip, tear, or damage the game pieces in a meaningful way. From our testing with Velcro on one roller the game pieces still have plenty of fuzz and we’ve been using one piece over and over.
I think like other people have said this will probably be a ref judgement decision unless there’s a rule update to specifically address it. If we’re not seeing rips and tears (or seeing a ball “skinned” after multiple cycles in one match) I’d imagine it won’t be brought up.
Keep in mind too not all Velcro is created equal. Some types are alot more “abrasive”
In addition to the very valid possible rule violations others have pointed out, if this strategy only works on CARGO in near-new condition, it is probably not an effective mechanism to use.
As mentioned in the manual and field tour videos, the quality and characteristics of the CARGO will vary tremendously and still be considered legal for play. Will your mechanism still work if your team (or others using hook and loop) have already played with the CARGO a few times?
I have noticed that the hook side of Velcro tends to load up with stray fibers over time which may reduce the “holding power”. I have not tested this extensively but recall replacing some that was no longer effective at holding.
We haven’t tested any velcro intakes precisely because we don’t want to damage the cargo. But I’ve noticed a number of the open alliance teams that have shown intakes with velcro seem to rip at the fuzzes in a way which I would be inclined to consider damaging if I were a referee. For example (not calling them out in any way) from 95’s build thread
If there isn’t an official statement on this in a team update soon, I can see it being acceptable. Power cells in 2020 were very susceptible to “chipping” which wildly changed how they flew, and this was announced by FIRST to be taken as a part of the game’s challenge. I don’t see how this is much different, although it could be argued that it’s somewhat intentional.
from https://youtu.be/OXkeAkWwex8?t=35 seems to suggest that if a robots intakes “good” cargo and produces the cargo on the right, then it is damaging the cargo. Otherwise …
I sure hope velcro doesn’t get banned explicitly for cargo interaction - from today it’s our leading intake prototype!
As others mentioned this should be covered by the general “don’t damage the field” rules.
From watching those earlier this week and then doing our own testing today the velcro “whips” look like they rip off more fuzz than what we encountered testing a velcro wheel and belt. I would speculate that’s due to the difference in the direction of force applied by the velcro, the “whips” in that video look like they are pulling in a shear fashion on the velcro-cargo connection which is where velcro is strongest (and you are most likely to see failure of one of the surfaces,
aka fuzz ripping off the ball).
For anyone playing around with using velcro speed of the velcro is a factor in how well it works. We found that there is a “sweet spot” for speed to get the velcro to grab the ball more consistently, if we ran our test setup too fast the velcro wouldn’t catch at all or it would rip itself off the ball after an initial grab. Some movement grabbed more consistently than a stationary wheel/belt. We need to experiment more to get a little more scientific on what that “sweet spot” is.
All of the file cards I have used over the last 40+ years have had steel bristles since they are meant to dig bits of metal out from between the teeth of a file made from hardened steel. It would be surprising if such a tool does not damage the Velcro which is made from some sort of plastic.
Yeah, I was just fiddling around with a prototype roller, so the survival of the velcro hooks was not my primary concern. Brass brush would probably be a LOT kinder to the hooks.
