Hi,
After test firing for an hour (about 150 test shots) we stripped off about 10 - 15% of the surface of the ball. The ball is still useable but sure is ugly. Any idea if there are limits to ball damage by a bot? Shooting a ball one time causes no noticeable damage…but 150 it becomes obvious to everyone.
Regards,
ChuckB
Generally in the past: Unless your robot rips a couple of new balls to pieces, the Ref usually won’t even question it. They expect wear and tear. So if you mess up an old ball, no worries.
They’ll replace balls as necessary to make sure they are reasonably consistent, but you have to take some variance into account in your design.
i noticed that the part where the 2 colours meet seperates very easily, and once there’s a rip it only gets worse.
however this dosn’t take out any chunks of the balls, the foam stays intact.
by limit i guess you mean when a ball would be taken out of the game?
i think as long as the ball keeps it’s original shape it’ll be kept in play… since balls can be scored on either net i doubt some colour wear would get them replaced.
unless they are worn down creamy coloured balls of foam?
anyways i apart from them being ugly i don’t think you should worry.
Ball wear is a definite concern, especially for shooter bots. Any non-sphericalness (yeah, I just called up Noah Webster and had that put in the dictionary) will distort the ball’s path. I’ve seen quite a few pics and movies around with people using belt sanders etc. to move balls - while I realize these are only mockups, similar methods will be used. So be advised - don’t design a robot that is based on perfectly round balls.
In 2001 the black balls which were inflatable became eggs. First just left them on the field as long at they were inflated. I suspect that balls will remain on the field as long as they can roll.
also just out of curiosity what kind of thrower are you using when you are messing up the balls, might it have something to do with the material the ball touches?
For reference, I put a question in at FIRST Q&A to see if they’ve set a criteria to determine when a ball is Too Pooped To Play. We shall see what we’re going to have to deal with.
Also teams need to consider how much the ball will be broken in…
a new ball when compacted will shoot further than a used ball that isn’t as tough and squishes easier
we played with the ball (in dodgeball fashion) around the shop and saw how much the ball was damaged after a few hours. Besides a few gashes and holes in the ball we seemed to make the ball alot less rounder than it was. Good thing we ordered an extra 24 we will have plenty more to use. When does first think the ball has expired?
What if a ball has split in half during a match. Like if it splits in half from being run over or just over use or shot too many times. How would FIRST score the two halves of the ball?
Well, if they were destroyed during firing, they probably wouldn’t roll down to the camera for scoring. If they were run over, they probably wouldn’t ever make it into a scoring area. Regardless, we will see a half of a ball score eventually.
I hope im there to get it on video so i can put it in this years robotics movie.
What about balls that get gashes or holes that might be still be playable. would anyone think that the balls should be allowed to still be used with some chunks taken out or gashes in them?
im wondering if there going to keep vacuming the field after every 10 or so matches. All the junk comming off these balls might make some interesting field conditions!
thats a good point the floor could get slippery in spots. Every match will differ because of the dust or parts of the ball getting ground into the carpet.
also time to cover up those gears. im gonna hope theres no big enough chunks to jam roller chain tho…
I think people are overestimating the damage that will occur to the balls. 150 shots with a ball is a lot. A ball will likely only get fired once a round on average. Most regionals have between 70 and 100 matches so a ball should probably last a whole regional under normal wear and tear. Also this wear and tear isn’t going to radically alter the shape or use of a ball like a gash. I think actual gashes will not happen that often. Especially with the constant use of bumpers, most robots are going to definitely just push balls away instead of driving over them(not that driving over them guarantees damage.) There was a huge fear that big robots knocking over the boxes in 2003’s game stack attack would just cause massive field destruction but it turned out to be unfounded. The reason being is that robots that cause damage to game pieces just can’t use them, so on the first sign of damage people start working on their robot fix it. By the time regionals come most robots will be pretty game piece friendly and those that aren’t will quickly become friendly. By nationals there will probably be almost no damage to the field pieces of any major amount.
that would be cool i have a shot of our robot destroying one of the plastic Tupperware Containers used in stack attack. :ahh:
Now if they would have used cubes we wouldn’t have this problem.
you may be right the damage to the balls may not be as much as currently noted. we have still been using the ball and it doesnt seem to get as torn up as it was the first time we were using it.
the balls i guess get tougher as they are used as well as change color
Our “shooter”, like most discussed on this thread, causes damage to the skin of the ball. Not a great amount, but enough that I have been following this thread and the related discussion on the Q&A forum. There have been a few questions asked regarding shooter mechanisms damaging the ball, and the Game Design Committee’s replies have been… well… rather severe.
I quote from thread: http://forums.usfirst.org/showthread.php?t=288
"…if your shooting mechanism tears off large chunks of the skin or clearly abrades the skin, it will not be allowed."
Interpreted at it’s most draconian, I suspect not many teams are going to be shooting balls.
I think our single-wheeled shooting mechanism is okay… but how is one to know?
Does any team have a shooter that does absolutely NO damage to the ball?
Jason