[waialua359]

Originally Posted by Ether

Hi Tom,

That is simply not true. With a free-spinning lower roller, the design approach is different: If you design it right, the ball is continuously rotating when being possessed. The backward rotation of the ball makes the ball follow the robot when the robot backs up.

In fact, there was a bot with a very effective ball magnet at GVSU that used a free-spinning lower roller bar and a motorized upper roller.

See this post: http://www.chiefdelphi.com/forums/sh...6&postcount=51


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Ours doesnt work quite like how you describe it. When the robot is idle, the ball doesnt spin since its wedged so tight with the roller. When we full reverse in low gear using an AM supershifter, the ball spins to follow the robot and we never lose possession of the ball. On our practice field, the ball did indeed continue to spin freely when the robot was idle. However, the carpet at the competition is slightly different from ours and doesnt allow our ball to spin at all.
My point is that the ball doesnt have to be continuously spinning to achieve constant possession of the ball moving backwards.