Is the wear of the ball a major factor as the year plays out?

Technical
#7

My experience with history says yes, it will be a factor. How much of one is yet to be seen, but keep your eyes open here on CD and you’ll get teams complaining soon enough if it’s major.

Good for your team for having the foresight to have that discussion.

You can, however, probably figure out some ways to compensate. Look back to 2016 and see what teams shoot well. Many will have blogs or technical papers discussing how they adjusted for it. It should give you a good place to start so you can figure how to improve on what they did.

#8

Short story. Do all your testing with one ball. Cover it in dust. Tear it up some. Now, when testing your prototype shooter, use that ball and a brand new ball. Increase squish until they fly the same.

8 Likes
#9

Definitely, the skin keeps the air from escaping quickly. As the skin breaks down from use, the ball compresses differently.

1 Like
#10

Absolutely, yes. Worn balls flew differently than new balls. When there was a mix of new and worn balls on the field, they all flew differently coming from rotary shooters. The most consistent Stronghold shooters were ones which were less reliant on the friction and elastic properties of the balls, such as catapults. With a shot load of 5 cells this year, expect a wide scatter pattern to your shots. It’s no coincidence that the opening to the high goal this year is so large.

For further insight, review game matches from Stronghold for bots with catapult style shooters and compare their effectiveness vs those in the same match with rotary shooters.

#11

Usually when the 2016 boulders went bad it involved one or more chunks missing and they were pulled off the field after the match. Probably the biggest cause was people driving over them.

#12

My recollection of Stronghold was that the balls did not wear too significantly with a wheeled shooter. If they did, they were removed from play.

Especially given the larger opening this year, I think wheeled shooters are a solid option. Catapults have a hard time shooting multiple balls quickly.

#13

Based on previous years, we can expect:

  • power cells with gouges will be removed from play
  • Well used power cells that have intact surfaces but are more compressible won’t be removed
  • robots that make power cells unplayable will be kept off the field

If you’re planning a wheeled shooter,make sure it doesn’t gouge the ball.

2 Likes
When will they replace game pieces?
#14

In 2016 I saw several times where a meccanum intake shredded a ball in seconds if it got stuck on something. LRI got involved, which you don’t want.
I expect FIRST will give us guidelines on when to replace the pieces.

#15

In 2012, the “basketballs” lost firmness from being run over and used. We had a pinch wheel shooter and found the accuracy suffered a little – mostly that shots fell a little shorter than they had originally – as the (week 1) regional went on. One mentor joked that we needed a “squishiness” sensor. In hindsight a design with some sort of auto tensioning (aka a spring) would have been nice. We solved it in software by increasing the speed of the shooter motor slightly as a regional went on.

#16

It is true the outside of the ball is pretty durable and any major damage they will replace the ball. The balls do get a little softer after a few matches. The largest effect on accuracy seemed to be when part of the ball would get soft like if it got stuck in a drive or mechanism on one side, and the other side would remain firm like new.

#17

Recommend looking more at 2006 than 2016 (and definitely vs 2012). The relative goal size—and orientation—is closer. This has the potential to be a much less a finessed shot than 2012 or even the single-shot 2016.

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#18

Don’t use a HiGrip (or any uneven tread) wheel shooter and you shouldn’t have any issues with tearing up the ball. HiGrips were what caused all the issues in 2016, our stealth wheel shooter and Colson testing didn’t ever really damage the balls.

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#19

Let’s hope FIRST has a sufficient inventory of Cells to avoid the 2012 CMP change in ball characteristics…

2 Likes
#20

4513 used 8 HiGrips to shoot in 2016. We were lucky to never have an issue with the ref’s with how quickly we tore up balls. Dont use them, theres way better wheels.

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#21

How did your team sleep at night knowing they were slaughtering boulders?

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#22

By taking a few hammers to the bot post-season.

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#23

Not if you use a catapult and steer clear of events with @Mitch_Stokes

#24

We got our order of 24 balls in yesterday, and they vary in diameter by as much as a centimeter…

1 Like
#25

I volunteer as Field Reset and am attending a Week 1 event to volunteer. I will update, if I remember the give and takeness. I started volunteering 2018. For Deep Space, we had 3 rings to measure cargo size. One would be the perfect size, one would be max tolerance (inflation wise) and the other would be min tolerance. We didn’t really replace the balls because the worst ones would’ve popped. I’ll see what the tolerance is this year but plan to be adjustable and tolerate small differences.

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#26

During competition, they’ll likely be cycled out if they get too worn out. Last year, hatches that had slightly messed up velcro got replaced and were fixed later. FIRST does a good job keeping only good condition game pieces in play, so I don’t believe that’ll be an issue.

Your specific team, on the other hand, may have to buy new cells after a few weeks if you’re really rough with them.