The robots in H.G. Wells’ War of the Worlds may have been terrifying, but they also had a feature notably lacking in a lot of today’s robots: the inherent stability of a tripod. But film realizations of the tripod robots have always suggested they moved in a sort of inefficient shuffle: if you were a tripod creature, how would you walk? Three-legged locomotion doesn’t make sense.
But researchers at Virginia Tech have begun development on a robot that looks like a tripod but has a simple and elegant gait. Check out this short movie clip showing how it works:
Clever, no? An article in New Scientist has the details:
To take a step forwards, the robot shifts its weight onto two of its legs, allowing itself to fall forwards away from the third leg. Its body then flips upside-down and the third leg swings up between the other two just in time to catch the ground and return STriDER to a stable tripod stance. To change direction, the robot simply switches its choice of swinging leg.
The body-flipping is the key to the whole thing: without flipping over, the robot’s legs would get tangled up faster than a kitten in a knitting basket. This arrangement has some disadvantages. You probably wouldn’t want to use a STriDER to transport loads, for example. The Virginia Tech researchers suggest using it to deploy sensors — its high vantage point makes it a great camera platform (imagine what Survivorman could do with a couple of these!).
Here’s a more extended video:
The only thing that seems odd to me is the way the robot in the animation is shown traveling through dense undergrowth. With lots of obstacles underfoot, wouldn’t it make more sense for the third leg to flip over the top of its body, rather than under the bottom?