pic: Team 148 - Robowranglers 2010 - Armadillo

[Paul Copioli]

With regards to the ball magnet, think of it this way:

If the normal force between the ball and the floor is less than the normal force generated between the ball and the "magnets", then the ball will stay possessed by the robot. This doesn't mean the normal force between the ball and the floor is zero.

The instance you see in the video near the goal was an implementation issue that has already been resolved. The ball will always be touching the floor when the magnet is on.

I can tell you this: we (148 + 217) created the ball magnet concept using only 9th grade geometry and 11th grade physics (1st semester).