Boston Dynamics and the US Defense Advanced Research Projects Agency (DARPA) have developed this amazing robotic cheetah that can run at 18 mph.  Testing of a free-running prototype is planned for later this year. Aside from the nasty military implications this may have , the thing that interests me about the movement is that although DARPA says that

The robot increases its stride and running speed by flexing and un-flexing its back on each step, much as an actual cheetah does

at the moment the body elongation and the range of flexibility isn’t nearly as great as videos of cheetahs actually show (compare the superimposed skeleton in the video below).  I’m going to guess that those will be the next steps in making the robot faster. Also, real cheetahs seem to get an extra spring and propulsion from their feet flexing, whereas the robot doesn’t really have feet, so that might be another direction of improvement.

Previously:  Big Dog