Meanwhile, Honda[1] and SRI [2] are catching up. Boston Dynamics' Atlas is too much like Big Dog; it weighs 700 pounds and uses hydraulics. Schaft is all-electric; they use liquid cooling so they can run the motors really hard if they have to. (That's how Tesla does it, too.) Boston Dynamics is working on better hydraulics, but electric motors are going to win this one for anything smaller than a pony.

[1] http://spectrum.ieee.org/automaton/robotics/humanoids/honda-... [2] http://spectrum.ieee.org/automaton/robotics/humanoids/durus-...