Re: Ball Magnet
 

Here's what were doing.....http://www.youtube.com/watch?v=K3Nb9NAxdeE.
We are building a full scale prototype with Banebot 20:1 26mm gearmotor and their 3 7/8 30A green wheels. Our students have played with this concept using one 20:1 Banebot gearmotor and a soccer ball. That playing was promissing enough for us to order the parts for a full size prototype that we are going to mount on our prototype holonomic drive.

Re: Ball Magnet
 

Yes Fredi, it's just the intake roller trying to suck in the ball, but there's a piece of wood blocking the ball so it can't go all the way in. Just a quick and dirty test of the roller idea to POSSESS the ball. We need to play with it more to optimize it, and fit it into the new robot chassis, but it works well enough as is that we are confident we can use the concept.

see, we did get one simple prototype done

Re: Ball Magnet
 

Nice job

I actually bought that same exact soccer ball yesterday. The Wilson HEX size 5 soccer ball

Im not sure, but wouldn't it be a good idea to try experimenting on carpet instead of a hard floor

Re: Ball Magnet
 

Cool. We did the same thing with our 2009 robot.

We got most of our inspiration from here => http://www.techunited.nl/index.php?p=11

If you mount some slides on either side of the ball you can even turn with it.

Running it on carpet changes things. Its harder to get the ball to spin on carpet, and if it stops spinning you lose control. Using small wheels instead of a board will allow it to spin more easily.

Re: Ball Magnet
 

Here's another video showing the concept in action in Robocup juniors....http://www.youtube.com/watch?v=sJAue5eAOkQ

Re: Ball Magnet
 

Too bad U6 soccer players aren't legal mechanisms to use. They play "magnet-ball", so there must be player/ball magnetism.

Re: Ball Magnet
 

We have also been looking closely at RoboCup robots.

The TechUnited Design has an awesome way to switch between a flat shot and a lob shot.

http://www.techunited.nl/index.php?p...ion_Movie_2009

Re: Ball Magnet
 

What motors have people been using for there magnets in testing? We had sucess with the 550's

Re: Ball Magnet
 

Seeing as a ball magnet is "just" an intake roller, pretty much any motor in the kit will do. The RS-555 is a motor you're not likely to need anywhere else, and I'd be hesitant to waste a CIM or FP unless you don't need it somewhere else.

Re: Ball Magnet
 

The one in our video is a Fisher Price, driving the gear from the first stage of the plastic transmission, then a further chain/sprocket reduction (I think it's about 1:3) to the roller.

Re: Ball Magnet
 

I believe the 555 motor this year is much weaker than in years past. The new motor has around 40 watts while the old ones were well over 100.

We were thinking of using the FP motor for our wheels, geared to give a surface velocity on the ball of 17 fps.

Re: Ball Magnet
 

Number 1 will the ball exceed the distance allowed into the robot? and if it doesn't will the magnet protrude to far from the robot?
Number 2 Does it count as being in contact with more than one ball if a ball is kicked into you while your carrying the ball?

Re: Ball Magnet
 

Answer #1......The ball is allowed to penetrate 3 inches into the robot. The design of the mechanism can manage this. The wheels you would typically use are only about 4 inches in diameter. That leaves room to mount the mechanism inside of the robot but yet have the mechanism wheels touch the ball.

Answer #2.......A ball that bounces off a ball in possession is not in possession since the robot is not controlling its orientation of the second ball. The rule says you can't be in possession of more than one ball.

Re: Ball Magnet
 

I don't mean to be asking you to post something that you don't want to reveal yet, but this has been the only application of this concept I have seen on an FRC bot.
Our team was inspired by some of the robocup bots we saw that used a similar mechanism to control the ball. But what we are having trouble with is figureing out how this works.
WE have a setup with a 1.5" tube spining at about 400 rpm, and it just seems to spin the ball a little, and then it kinda bounces off the roller and away.
What is the concept of how this works? (if you don't mind) or if someone else can fill me in.

Re: Ball Magnet
 

one thing to make sure you play with is different contact points between the ball and roller as well as different "sticky" surfaces