For some time, one of the biggest enabling technology constraints with designing robots has been in producing an effective approach to locomotion. On the straight and level, they were ok, but on rough terrain, they have problems. The challenges involved in designing an effective solution - intelligent, concurrent control and feedback for each autonomous leg, rapid assessment of difficult terrain, recovering from stumbles - are all hard computing problems and must be tackled in combination with other design issues, like choosing the right actuator system (which must provide many more than six degrees of freedom), and developing a product that is a managable, yet useful, size.

Progress is being made. In the latest 'walking robot' from Boston Dynamics, 'Big Dog', the prototype can climb, run, jump, and even recover from slips. The prototype is noisy (a gasoline-powered generator is the power supply), which reinforces again how much improvements to portable power will become catalysts for subsequent innovations. But the progress that's been made in robot kinematics in just the last few years is phenomenal. It reminds me quite a bit of a Hunter from Half Life.

This isn't some scam - see a detailed illustration of the mechanicals here. Big Dog is being designed as a pack animal for the military. It walks at 4 mph, climbs slopes up to 35 degrees, walks across rubble, and can carry up to a 340 lb load. I can see the day in the future when you no longer will have to feed your horse hay and oats - you'll just plug it in! But of course, that will depend upon whether the robots rise up and revolt first!