20 August 2008

Nice legs; shame about the voice...

In a recently filed article for Scientific Computing World (appearing next month: plug!) I mention in passing a general consensus that hexapods are the best compromise between stability and data analytic complexity in "walker" robots. Gayle Reynolds, however, points out that MIT spin off Boston Dynamics, with DARPA funding, have chosen to make a quadruped named BigDog their centrepiece.

It looks like a spider that's missing four legs, sounds like an enormous bee, and it's certainly something I wouldn't want to see coming at me in the dark. (Gayle Reynolds)

Watch the video here to see what she means – especially the bit about sounding like an enormous bee.

I dislike military robots, and money poured into military programmes, though I doubt than my distaste will change anything. From a practical military point of view, Gayle's comment about the noise (result of running on an internal combustion engine) is significant: if I were a soldier in the field, I would want to put considerable distance between myself and anything attracting attention with that sort of racket. At the same time, I can't help being intellectually interested. In particular, I am deeply impressed by the way it recovered its footing after slipping and skidding on ice halfway through the video.

This is obviously intended to be an intelligent mechanical load carrier, accompanying infantry over terrain inaccessible to wheeled or tracked support, and it could be extremely good at that. I can only hope that, once developed, the technology will also be applied to more socially useful contexts like disaster relief. In the rubble of an earthquake stricken city, for example, BigDog could serve as a heavy equipment carrier for search, rescue and paramedic teams. It could be a mobile instrument platform searching hazardous partially collapsed structures for survivors, perhaps ferrying in quantities of RHex (or even appropriately equipped RiSE) hitch hikers to penetrate smaller and less accessible spaces. It could even mount equipment to start digging for those survivors, or prepare the ground for human rescuers.

7 comments:

Julie Heyward said...

My Jack Russells would do terrible things to that critter if they caught it alone in the woods, as shown. *shuddering*

A giant runaway vacuum cleaner...

Is DARPA aware of terriers?

Poor Pothecary said...

I don't know if you mentioned it in your article, but it always troubles me in SF movies is that nobody on the FX side appears to have thought through tripod gait (i.e. in War of the Worlds and The Tripods). It's not much more stable than biped gait, because to lift one foot up and move it, you have to be moving through a temporarily unstable balance on the other two. See Tripod Gait for some nice animations.

Felix Grant said...

Julie: no, I don't think DARPA is aware of terriers!

Gayle Reynolds, who sparked this in the first place, comments by email: "I'd almost bet money that DARPA is unaware of anything that doesn't run over things, crush, and blow everything up with big BOOM sounds ... which probably accounts for the obnoxious bee noise."

Though, of course, ARPA was responsible for this intrnet which we are cheerfully using to badmouth it [grin].

Felix Grant said...

Poor Pothecary: no, I didn't mention tripedal walkers at all ... I'm afraid space constraints squeezed out all but a look at the human related applicability of bipedals...

Your link was fascinating, though. I'd always imagined tripods as one-leg-at-a-time beasts, the alternatives shown set me thinking...

I can imagine another tripedal mode: only one foot on the ground at a time, the other two being at intermediate points of a lift-and-forward motion?

My brother once built a three footed Meccano "tumbler", the legs being radial spokes of an imaginary wheel with the "body" at the hub, one and two feet alternating. I also had a toy when I was a bout seven: a bug with a similar three spoked arrangement of rubber suction cups under its belly which enabled it to walk up windows, one cup releasing as the next adhered...

Poor Pothecary said...

I can imagine another tripedal mode:

It might be what Wells had in mind with his description "Can you imagine a milking stool tilted and bowled violently along the ground?"

a bug with a similar three spoked arrangement of rubber suction cups

So did I. Yellow, shaped like a slug, with a smiley face? And it'd go shlup ... shlup ... shlup ... up the wall until running out of, well, mainly spit on the suction cups, and then fall off. I can't remember what it was called. The idea has been reinvented / rehashed many times, and they're still making hi-tech versions like this one.

Felix Grant said...

Mine was red and less of a slug than a sort of hemisphere with fish tail through which a string was pulled to tension the string which powered it ... but yes, it had a cheery if somewhat fixed smile and the Schlup Schlup Schlup!

It never fell off ... on the contrary it just stopped and remained stuck, too high for a seven year old to reach, until a passing adult could be induced to retrieve it.

Eventually, my brother dismantled it to see how it worked ... after which, it didn't. Some years later he did the same to the family car.

Poor Pothecary said...

sort of hemisphere with fish tail through which a string was pulled to tension

Yeah, definitely same thing, colour variant. It's mildly irritating that I can't think of the name. What I can remember, which suggests I was very small at the time, was my reaction to the name, which I felt very peculiar because it wasn't (classification I later appreciated to be) a Proper Noun - "Thing" or "It" or "That" or similar.