A unique three-legged robot called "STriDER" is under development at Virginia Tech University. It's name stands for (Self-excited Tripedal Dynamic Experimental Robot. This cunning four-foot tall stick-figure bot has a totally unique way of walking. One researcher described it as being like "a biped with a walking stick."

The STriDER robot is able to change direction by selecting which of its legs to swing through. Two of its legs stand still, and the small body swings underneath and plants the third leg. The robot repeats the process to move forward, swinging this way and that (see video).

One of the researchers revealed these details (see also diagram):

[STriDER] “is a novel three-legged walking machine that exploits the concept of actuated passive dynamic locomotion to dynamically walk with high energy efficiency and minimal control. Unlike other passive dynamic walking machines, this unique tripedal locomotion robot is inherently stable with its tripod stance and can change directions while walking.”

As soon as I read about the STriDER robot, I thought immediately of the "spiders" - three-legged bots that roamed the vast interior of the alien craft in Rendezvous With Rama, the award-winning1972 novel by famed science fiction writer Arthur C. Clarke:

Ten metres away was a slender-legged tripod surmounted by a spherical body no larger than a football. Set around the body were three large, expressionless eyes, apparently giving 360 degrees of vision, and trailing beneath it were three whiplike tendrils. The creature was not quite as tall as a man, and looked far too fragile to be dangerous, but that did not excuse their carelessness in letting it sneak up on them unawares. It reminded Norton of nothing so much as a three-legged spider, or daddy-long-legs, and he wondered how it had solved the problem - never challenged by any creature on Earth - of tripedal locomotion. (Read more about Clarke's spider tripod robot)

If you admire robots with a unique means of movement, take a look at Mowgli the Leaping Frog Robot.

(This Science Fiction in the News story used with permission of Technovelgy.com - where science meets fiction

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