Martian tripod robot

Martian Petit tripedal robot. © Osaka University.

Most mammals are four-legged, with very few exceptions being occasionally or completely bipedal. But the animal kingdom has no examples of three-legged animals; the kangaroo, which uses its tail for balance, is not considered to be truly tripedal. To explore this further, Yoichi Masuda and his colleagues at Osaka University decided to build three-legged robots, inspired by the Martian robots in HG Wells’ 1898 sci-fi novel “War of the Worlds”. Previous experiments like STriDER (2007) had shown that until now, three-legged robots were at best “intermittent bipeds”, using only two out of three legs at any given time. But Masuda’s tripod, called Martian Petit, is different. His robot has not only trilateral symmetry but a trilateral gait as well. In other words, the three legs are identical, each moving in a similar way. But performance is not the best and, watching Martian Petit walk, you can guess why Evolution went for even leg numbers. Researchers led by Masato Ishikawa, a professor of mechanical engineering at Osaka University, are already working on the next version, with a few extra degrees of freedom (and consequently more complex dynamics) in the legs to continue exploring problems and limitations in tripedism.

⇨ IEEE Spectrum, “Martian-inspired tripod walking robot generates its own gaits.”