About a year ago, we ran a story about a four-legged "robotic pack-mule" being developed for the US military by a company called Boston Dynamics. This video shows what appears to be a new prototype called BigDog. It seems more energetic than the original, and even has the ability to leap over obstacles (01:55 secs).
Such a gasoline-powered beast of burden could eventually be used to lug heavy packs around for soldiers travelling on foot. Sensors feed information to an on-board computer that makes rapid adjustments to each of its four hydraulically-driven legs to keep BigDog balanced. The resulting movement is surprisingly life-like, and lets the robot navigate uneven ground and keep itself steady even when given a hefty kick.
Will Knight, online technology editor