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infocus 19-02-2010 17:42

Rollers with official game piece
 
Has any team been able to successfully use a ball magnet with the official game piece? We have two prototype rollers built onto our robot as of now. They work perfectly fine with regular store bought soccer balls. However, as soon as we switch to the official game piece, they snag the ball and pull it under. We can't seem to get a roller that can grab the official ball well. We are using a banebots 20:1 with a fisher price. Any thoughts? We need some help.

Bob Steele 19-02-2010 17:51

Re: Rollers with official game piece
 
What is the material you are using for your roller?
What surface speed are you running the rollers?
Where is your roller contacting the ball?
Is it a continuous roller with one point of contact or two or more separate rollers?

If you can find a surface with a lower coefficient of friction with the ball you might do better. Two points of contact on either side of the ball would allow a little better control also.

You might also reduce the roller speed...check out lower speeds and see what happens...

good luck

infocus 19-02-2010 18:19

Re: Rollers with official game piece
 
Our roller is a piece of PVC, but we've been wrapping it with different materials . The result is usually the same, but when we wrap it with a lower friction material, it hardly catches at all. We are running the fisher price at all different speeds with a planetary gear box, but haven't calculated the surface speed. or roller contacts the ball about 3/4 or so of the balls height. We are using a continuous roller at the moment.
We have tried lower speeds but the result remains the same.

NOV8R 19-02-2010 18:31

Re: Rollers with official game piece
 
1583 is usuing two of the banebot 20:1 gearboxes with FPs. For the rollers we are using banebot 3 7/8 60d (orange) wheels. We vary the speed depending on what we want to do. We have a variety of balls and it seems to work equally as well on all of them. We've found that for ball aquisition the wheels need to spin slow. To move with the ball backwards or left & right faster. We're going to a scrimage tomorrow and we'll let you know more then. Best advice is try the wheels instead of a roller.

CidTeach 19-02-2010 23:06

Re: Rollers with official game piece
 
our team is also dealing with the sensitivity of the official game piece. Seems like the outer plastic coating is very picky and sticky. it deforms rather easy due to the deep stitching and grabs our rollers - also pvc tube.
any thoughts on a passive system to just guide the ball??
goodluck.

gblake 19-02-2010 23:47

Re: Rollers with official game piece
 
How about putting some guardrails (sort of like the cow-catcher on the front of a locomotive) in the ball magnet region of the robot. Use them to ensure the ball can't get pulled too far into/under the robot/roller.

MrForbes 19-02-2010 23:53

Re: Rollers with official game piece
 
We have ours working reasonably well with the right ball.

http://www.youtube.com/watch?v=25rqm88gAXU


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