Advanced Robot Locomotion

From IEEE Spectrum:  A basic example of biomimicry.   Are four legs required for precise and varied terrain robotic locomotion?   Here a new example with quadropedic motion, and video.   Impressive developments.  " ... In 2011, researchers at the Italian Institute of Technology unveiled HyQ, a quadruped powered by actively compliant hydraulic legs that can adjust their stiffness in real time. The researchers initially taught HyQ to walk and trot, and last year it learned how to avoid stumbles. Now HyQ is back with some new skills. In one demonstration, it was able to traverse inclines without slipping. The robot is also learning to use its perception sensors to react to disturbances—a capability the researchers tested by slamming their robot with a punching bag. ... "