There is a great documentary talking to the guys who engineered the robot. Interesting story they are a couple of research students at University of Tokyo wanting to develop the robot for the DARPA Robotics Challenge, but there is a rule at the University that no military funded projects are allowed. So these guys are doing it independently, pretty awesome guys I wish them the best. In the documentary[1], you can see how SCHAFT robot works in detail.
[1] http://www.youtube.com/watch?v=DKiXM7bUypk&t=25m0s