Boston Dynamics just released a new video of Big Dog, their very impressive walking robot. This time it tackles snow, ice and jumping, as well as its old party trick of recovering after being kicked. Apparently it can carry 150 Kg too. This is an extremely impressive demo – it seems light-years ahead of other walking robot’s I’ve seen.
I must admit to having almost no idea how the robot works. Apparently it uses joint sensors, foot pressure, gyroscope and stereo vision. Judging from the speed of the reactions, I doubt vision plays much of a role. It looks like the control is purely reactive – the robot internally generates a simple gait (ignoring the environment), and then responds to disturbances to try and keep itself stable. While they’ve obviously got a pretty awesome controller, even passive mechanical systems can be surprisingly stable with good design – have a look at this self-stabilizing bicycle.
The one part of the video where it looks like the control isn’t purely reactive is the sped-up sequence towards the end where it climbs over building rubble. There it does seem to be choosing its foot placement. I would guess they’re just beginning to integrate some vision information. Unsurprisingly, walking with planning is currently much slower than “walking by moving your legs”.
Either way, I guess DARPA will be suitably impressed.
Update: More details on how the robot works here.