Meet LittleDog, DARPA's Small Quadruped Robot

A report from our correspondent Sally Adee, who earlier this month was at DARPATech, the Pentagon's R&D extravaganza, where she met, among other creatures, a little robotic dog called, well, Little Dog:

This little guy was all the rage at the DARPATech 2007 exhibit hall.

''Can I pet him?'' a girl asked the researchers standing next to it. ''No,'' they told her. ''Can I have him?'' she insisted. ''No, sorry." She thought about it for a minute. ''Can I talk to him?'' she finally asked. ''Well, you could,'' the researchers said testily, ''but it can't hear you.''

If you're wondering why the researchers appeared so cranky, it was probably because visitor after visitor, fascinated by the little critter's attempts to negotiate its obstacle course, only wanted to know how the robot was built, how many actuators it had, what sensors and battery it carried. The perpetually exasperated response: "It's not about the robot! The important thing here is the software."

Little Dog, developed by Boston Dynamics, is part of DARPA's Learning Locomotion program. DARPA selected six teams, each of which received one Little Dog unit. The teams will have to write locomotion software to make the robot traverse an irregular surface with various obstacles.

Alas, it's a lot harder to get excited about abstract software. The researchers repeatedly tried to redirect our attention to the big screens above Little Dog showing essentially what was going on in his head. The cameras above the display mapped out the terrain in detail and sent a path to the machineâ''s processor.

This particular version of Little Dog meticulously plans its every move before it takes its first step. It was a peculiar sight: Little Dog standing transfixed at the start of its obstacle course, staring intently at the road ahead, as the screens flashed and changed and check marks were applied to tasks. It's not everyday you can peek into a dog's brain.

And then Little Dog begins to move. One leg tentatively snakes forward and gingerly tests the ground in front of it before the machine puts its full weight on the foot. This software has a lot to keep track of: it has to distribute the machineâ''s weight properly to keep Little Dog from losing its balance, all the while locating itself within its physical surroundings. Not all Little Dogs will navigate the obstacle course the same way. UPennâ''s Little Dog, for instance, has a different locomotion software than MITâ''s Little Dog.

Despite its name, Little Dog's shape was a matter of debate -- a Rorschach test of sorts. When observers compared his movements to those of a cat, cat people immediately came out of the woodwork to point out that his movements much more accurately resembled those of a roach. â''His legs arenâ''t articulated at all like a catâ''s,â'' said Spectrum senior editor Jean Kumagai, herself a cat person.

But everyone agreed that the least of all resembled a dog. At which point the beleaguered researchers would again try to steer the conversation back to the abstract code powering the machine.




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