Say hello to Kenshiro, a 5'2" humanoid robot that moves with creepy precision. While other human-like machines such as DARPA's Petman plod along clumsily as if they could fall at any time, Kenshiro's individual arms, legs, and spine can bend and rotate with unnerving realism. The key is in his advanced musculoskeletal structure, which researchers at Tokyo University's JSK Lab have been refining since 2001, starting first with Kenshiro's predecessor, Kenta.

Built to the scale of a 12-year-old boy, the 110-pound bot is supported by an aluminum skeleton providing a structure for some 160 artificial muscles. These cables and motors allow for incredibly complex movements (my favorite is the knee-bend at the 1:09 mark) that look as close to natural yet as we've seen on a machine. 

Biomimicry on this detailed a scale, however, is no easy job. "The muscles, bone structure, and spine are meant to work and flex the ways ours do," says Devin Coldewey at NBC News. That means "striking a balance between weight, power, and speed" of Kenshiro's individual components, in much the same way the relative weight of our bones and other parts are crucial for everyday functioning. 

Don't worry, though. The human body contains around 640 muscles, give or take a few, so Kenshiro still has a long way to go before he can move around with the full range of motion that comes naturally to most living, breathing humans. And even if this Astro Boy in the making somehow becomes self-aware and feels compelled to destroy humankind, he'll still have a pretty tough time trying to chase anyone down. (Via Gizmag, LiveScience)