Re: Ball Magnets
 

Very nice, we have a light for that purpose on our robot too. On a side note did you model after that robotic soccer league ball magnet. They look very similar.:rolleyes:

Re: Ball Magnets
 

These are edge cases, not the norm. I would rather improve my robot's functions than take a chance on being an outlier.

Re: Ball Magnets
 

522 and 148 were both the final pick in their divisions and in 2007 the only team that could not control tubes that went far was 190 and that was an alliance that was just strangely awesome in it's success so I don't think that really proves your point however I do agree that a team can be extremely successful as a scorer without ball control as long as they have great driving and great strategy as 230 has already proved by winning wpi very convincingly.

Also in this game you can be a strong defender or a striker with a robot that just moves well. 2265 proved to me at NYC that any team can come out and play absolute shut down defense if they have a proper drivetrain and good driving. 34 is nothing but a mecanum driving bot and they were one of the best scorers in the early regionals.

Getting back to the point of this thread, I would personally make the roller run by a motor, because an idling roller really defeats the purpose since you guys don't have trouble pushing the ball. I would slap it on the bot and see how it works during practice matches. If anything you could always go back to the way things were. There isn't that much risk in this situation and the reward could be great. You guys are one of the best scoring machines out there but if you have a roller that doesn't take away from your other success you could become that much more difficult to defend and ultimately defeat.

Re: Ball Magnets
 

What is the actual distinction between a "ball magnet" or rollers?

I was under the impression ball magnet was a blanket term for any ball-control device.

Re: Ball Magnets
 

Hi BJC....Yes we found that robocup ball dribbler video early on in the design process. Our first prototype worked well enough to keep our interest and our refined ball magnet is even better than even the one in the video. Here's another video http://www.rambotics.com/video7.html that shows our driver practicing with our practice robot and improved dribbler.. We thought ball control was more important than a kicker to practice with so we didn't even put a kicker on our practice bot.

Re: Ball Magnets
 

One thing we do to help this is to adjust the speeds of the Mecanum wheels so the center of turn of the robot is near the center of the ball.

We also use and FP and I believe we use about a 4:1 speed increase to a 1" diameter roller.

We covered our roller with a small diameter bicycle inner tube. To get the inner tube stretched over the roller, we put the aluminum roller inside a steel pipe and stretched just a bit of the inner tube over the pipe. Pressurizing the pipe inflates the tube and the roller drops right in - then trim the inner tube to length.

A couple of other notes. To get variable shot selection we reverse the direction of the roller just before the kick to push the ball out in front a bit. By varying the lead time, we can get a good shot from all three zones even though the kicking force is the same all the time.

Also, when driving forward with the ball magnet pulling the ball into the robot, our robot would start to "power hop". We reverse the roller with speed propotionate the forward speed to avoid this.

Re: Ball Magnets
 

Magnets hold on to things. They don't drop the things they are holding on to when they move backwards or turn around.

148 has a ball magnet. 217 has a ball magnet. 1114 has a ball magnet. These types of things are often imitated, but never duplicated.

Re: Ball Magnets
 

What would you consider something like what 1726 has where the ball spins in front of the bot instead of inside it. They still hold onto the ball when they back up its just different. It would be ironic if that had another name since 1726 coined the term ball magnet I believe.

Re: Ball Magnets
 

The term "Ball Magnet" originated from 1726, who has a good, but imperfect single roller. I think it would be unfair to take this away from them because they're not as good as Team IFI.

My team's been using the name, as every possession mechanism we've made is an iteration of that original design. I guess we'll stick to "the vacuum" now, though.

Re: Ball Magnets
 

Single rollers can be ball magnets, too. They're the ferrite equivalent of the rare earth ball magnets used by 148/1114/1868/etc. :)

Re: Ball Magnets
 

I believe that magnets do drop things, some more than others, but magnets do drop things. A ball magnet is really any mechanism designed to posses balls. I understand not counting adhesives as ball magnets, but vacuums, rollers, and pincher bars all fall into the category of 'ball magnets'.

Re: Ball Magnets
 

"ball magnet" is just a silly name I came up with for this video

http://www.youtube.com/watch?v=KRqj0Mgbq10

good to see it continues to stir up so much controversy

And kudos to those teams who made one that works well....

Re: Ball Magnets
 

Nice design. It looks like your driver is "tender" with the robot when he is driving it. I would really recommend he push the robot to its limits and see where they are. At competition, it's really hard to be that tender and still expect to score 4+ goals a match.

I too was under the impression that a ball magnet was a general word for something that possessed a ball, and wasn't aware that there is a design aspect to the word.

Re: Ball Magnets
 

Unless said magnets are part of a magnetized screwdriver and you are trying to place a screw in a very awkward place.

Re: Ball Magnets
 

It's kind of funny how off topic this thread has gotten.

Anyway, I would suggest if you don't want to do anything else line the front of the robot with memory foam (the stuff in the goal). That in itself will help alot:ahh:. Although, if you are going for more of a BALL MAGNET (I think i used it right) then it will take testing and probably some practice rounds.

Just remember, if you go with a single rollor get it as high on the ball as possible. If you are going for a pincher use a smaller diameter roller and be careful the bottom roller clears the bump (many teams who use this designed for it since the beginning). Also remember that a vacuum takes the most weight. Finally, all of these take time to impliment so you need to be sure your prepared to possibly use all your practice time to get it to work; they can be tempramental.

Although, like stated earlier you don't really have anything to lose, so I would go for it.

Good Luck:)