POPPED - Cargo Inflation PSI and Failures


#21

G15 says that popping counts, but due to how common it’s becoming they might change that or change the penalty.

EDIT: changed wording


#22

Should I ask this in the Q&A?


#23

We initially inflated ours to a fairly low pressure and size while we were looking for the regulation size in the manual. Once we found it, we inflated ours to 13" and I never felt like it was anywhere close to popping. I was watching the pressure gauge on the pump while we did the second step in the inflation and the pressure on the gauge was not really changing. The cargo just got bigger the pressure inside was not really increasing very much. I think there is still a decent amount of elasticity left.


#24

My guess is that the rule on popping cargo is to prevent strategic popping. Before a match, teams should be able to talk to the referees, and look at the cargo. One thought is to point out which cargo has the best chance of popping, so that the judges know you aren’t just popping them to make them a consistent size.

FIRST may also be waiting to say this, to make teams sweat, and design a mechanism that will cause the least damage possible before telling them it doesn’t matter as much.


#25

If it does prove to be a problem with the cargo itself, then I don’t think FIRST will severely penalize teams unless your robot just wrecks cargo every time


#26

Wow, we just blew ours up to 13" on kickoff day without even thinking about it. Y’all are scaring me!

Anyway, thanks everyone for the heads-up. We’ll definitely start out with our roller slower to make sure we don’t burn through.


#27

We went to ~13" on kickoff without any problems, on several team’s cargos.

Good note on high speed rollers/melting - we’ll have to watch out for that too.

Penalties will be called on every pop, whether or not it feels fair to the team in contact when it happens.
Penalties will quickly escalate to yellow and red cards if a robot consistently destroys cargo (ie more than once in an event).
Veteran teams will be stepping in to help teams fix their 'bots, but don’t expect to do the same thing over and over and not get penalties.
The program can’t afford to have a high rate of field piece damage.


#28

I think that a question asking if every pop of a ball will be issued a foul for G15 would be a quite reasonable Q&A question, and might help lead to more consistent enforcement of G15 at events. Or maybe you’ll get a “It’s up to your referees” response, but I think it won’t hurt to ask.


#29

I inflated our KOP ball until it looked good. Measured only 1 PSI and the diameter was only 12. Pumped it up gradually til it measured 13, PSI went to 6, tight. About 30 minutes later of being bounced around, it looked too big. It measured 14 and the PSI was down to 3. Deflated down to 13 again. PSI is 2.
Next one, I will underinflate and leave it a day. Or maybe it should be overinflated to break it in and make sure it won’t pop and then deflate to 13.? Or maybe both.
Maybe FIRST will have a way to get them stable.


#30

We have kept ours inflated, at a 13in diameter and have not popped them yet except for rolling one over a zip tie. The one thing I would note, we have had some extreme discrepancies in ball shape. Some much more egg shape than others.


#31

We popped our first one, we think its because it was over-inflated >13.5".

Since then, we’ve gotten 3 more, and to be safe tried to make sure we were inflating closer to 13" than what can be eyeballed by holding a measuring tape over the cargo, and measuring it that way:

  • Take a thin piece of rope, cut it the circumference of the ball that you want: ie. 13" * π = ~ 40.84"
  • Inflate the ball, until the rope is a snug fit around the biggest part of the ball (we’ve followed the seam and been okay)

Ideas were tossed around about 3D printing a jig, or quickly cutting one out on the router.

We haven’t had issues since doing this, there is some “oblong-ness” but it hasn’t been an issue yet.

The one we did pop had a straight line through it, likely caused by the edge of our roller digging into the ball.


#32

False, we did not go to ~13" on Kickoff morning, and I’ve sent a note out to the teams that attended that they should finish inflating their Cargo.

We’ve been focused on hatch handling, but we’ll probably have to redo a bunch of cargo handling tests now. Oops.

We’ll build a Cargo Measurer at our lab next week.


#33

Remember to test CARGOs which are smaller, proper, and larger than spec, because if this year is like others, field reset will be directed to not pull game pieces which are only “slightly” out of spec.


#34

we inflated our first one to what we thought was 13.0" Then we made a pi tape only to see that we had 13.5. It does just fine at this point. We have 5 more coming from AM and will inflate them all to different sizes to verify our system.