There are of course biped robots that walk. The Honda Asimo is the best known. But the Asimo doesn’t balance dynamically. Its walk is preprogrammed; if you had it walk twice across the same space, it would put its feet down in exactly the same place the second time. And of course the floor has to be hard and flat.
Dynamically balancing—the way we walk—is much harder. It looks fairly smooth when we do it, but it’s really a controlled fall. At any given moment you have to think (or at least, your body does) about which direction you’re falling, and put your foot down in exactly the right place to push you in the direction you want to go. Practice makes it seem easy to us, but it’s a very hard problem to solve. Something as tall as a human becomes irretrievably off balance very rapidly.
This is important because robots that dynamically balance can handle arbitrary terrains and can withstand attempts to knock them over, much like the Big Dog robot we reported on earlier, whereas pre-programmed robots like Asimo cannot. If Honda were smart, they’d buy AnyBot ASAP.
Here’s a link to the Slashdot article on this.