[EricH]

Originally Posted by Max Boord

How exactly do you get traction without attaching to the field carpet?

Friction.

Here's an example of the difference between traction by friction and traction by attaching. Go outside to your back yard (if you have one--if not, try the front yard). Push your hand down flat on the grass and try to slide it--it'll probably move (though not necessarily easily). Now, instead of a flat hand, use a hand in a hook shape, digging in (or just grab a handful of grass). Doesn't move, does it? Now, just for good measure... grab that handful of grass and yank hard on it.

Now, that's a bit simplistic. But it's kind of what we're getting at here. Most robots will be using friction (yes, there's microscale interactions with the carpet and all, but for the most part that's counted as a slightly higher mu value). Maybe a robot uses attaching--see what happens when you grab and pull grass. That's what the difference is.