Given the difficulties involved with figuring out how to make machines walk, it's no surprise that some roboticists are turning to arthropods as models. After all, insects and spiders and such are able to move pretty readily on some fairly simple hardware (including exceedingly simple brains). A machine would be doing very well to be able to match arthropod articulation. Are they there yet? You be the judge.
Frank Kirchner, a roboticist from the University of Bremen, is collaborating with Silvano Colombano at NASA's Ames Research Center in the development of an eight-legged robot with walking behaviors based on that of the scorpion. The Scorpion (as that is its name, of course) is able to sense changes in terrain and respond accordingly. Nature News has a brief write-up of the technology, along with a video of the Scorpion in action which demonstrates how far biomimetic robot mobility has come, and how far it still needs to go.
Future generations of the Scorpion may be crawling along rocky crevasses on Mars (perhaps carried as the payload of a Gashopper) and through buildings knocked down by earthquakes or other disasters here on Earth.
Something like this would be a VERY cool replacement for a power wheelchair!
All I can say is those NASA boys are lame, their robot could hardly move. If you want to see what real geeks can do when inspired by biology but not slavishly imitating it go to :
They have several movies showing their little robot running, climbing over objects, and even jumping up stairs! All with just one motor and one servo.
The whole biorobot program at Case Western Reserve seems to be a lot more advanced than what NASA is showing.