PUlling Goals

[Lloyd Burns]

Kinda late to chime in, but the biggest problem is trying to pull casters in the direction they point to: You have to pull the caster around, sliding the wheel into its turn (friction); you have to push the wheel sideways, which makes the pulled object want to move sideways (pushing the casters which haven't turned or which are about to turn, sideways [=friction]); then, past perpendicular to direction of pull, you have to do it all in the opposite sense, in reverse order. Only once all the casters have "castered" can you get the lower friction of the wheel / axle system.

The type used on the goal has the vertical "axle" in the plane of the wheel, and is much more difficult to turn under load than to pull.

One year, we used a front-drive robot with rear casters, that was geared to run too fast - every second time we changed direction, the breaker opened due to the caster-turn load.