Upon recieving the balls in the KOP, we’ve noticed that some of them are harder, or less squishy, than the others. We’d like to know if this was supposed to happen and it will be that way on the field in competition or if it’s the manufacturer’s fault. Thx(:
I noticed if you rip the cover a little, accidental testing incident, any memory like effect the ball has goes away. Not sure if that what your noticing.
It would be wise to design your manipulator to account for variability in the balls, just in case.
We have the same problem. We noticed the basketballs we got in the KOP were less squishy than the ones we ordered from first choice (those are almost memory foam like). Since we havent really heard of any other complaints, we’re going to assume the KOP basketballs are the competition regulation, if thats safe to say.
Doesn’t really make sense though, usually FIRST mass orders all of the games pieces, so why they’re different is just weird.
It might be a good idea not to assume anything.
You can be SURE that the balls will behave differently in the competition in the sense that no two will behave EXACTLY the same.
They WILL have rips, cuts, dents and other irregularities and they will probably not be replaced until they become almost unusable.
Variation is what you have to live with in the FIRST games. That’s the way real life works too. Design robots accordingly.
In 2009 the balls would break and we had to test to see if our mechanisms would accept a broken ball.
Last year wasn’t so bad, but the tubes weren’t always blown up to exact dimensions (either at competitions or at home). They would pop too.
If you’ve got a spinning-wheel shooter, see if you can compress the balls enough that the difference in squishiness doesn’t matter (or if normal compression works like this anyways). I’m guessing that this will work. (But don’t take my word for it.)
We’ve hypothesized that this difference in behavior is due to the air-tightness of the ball’s outer surface. If you take a brand new ball and squish it all the way, the air rushes out and takes time to find the few holes in the ball’s skin as it rushes back in. However, an old ball with cuts and tears in it appears to bounce back because the air can rush in faster.
If you’re going to assume anything, assume they’ll bounce back. Our guess is that they’ll probably all be like that after the first match (definitely after Thursday at competitions). However, it’s better not to assume anything. Different balls will have different surface features, even older balls may be slow to bounce back also as the foam wears out. It’s best to build a ball-ejecting mechanism that doesn’t care how fresh or messed up the balls are.
Hope that helps!
Don’t. We got both types in the Kickoff KOP. It doesn’t seem to be solely and wear and tear issue, though that certainly contributes. We have several balls that, while provided by the KOP and/or FIRSTChoice are very obviously manufactured differently to the point of different densities, surface finishes (sheens, hardnesses) and manufacturing hole methods.