We got our first look at Boston Dynamics new bigger, badder, and bigger and badder BigDog back in September, and DARPA's already gotten on the horse and saddled up the bot with a bunch of luggage and chased it out into the wilderness to see how it'll do.
In the footage we saw in September, we didn't get a good sense of how much quieter AlphaDog was going to be (because at Boston Dynamics labs the robot was powered by off-board hydraulics). The vid above shows that while it's certainly not what you'd call stealthy, it's at least slightly quieter than the original BigDog, with a tone that sounds more mechanical and less giant angry bees.
DARPA says that "physical overburden" is one of the biggest problems facing soldiers today. We've got lots of great technology designed to keep warfighters safe and give them an advantage in combat, but all that stuff adds up to the point where having to lug around 45 kilograms (100 pounds) of gear is not unheard of. The job of the LS3 (Legged Squad Support System) is to act as a pack mule, carrying up to 181 kilograms (400 pounds) of gear so that the humans can take it easy for a change.
We already know that BigDog and AlphaDog are capable of negotiating steep and slippery terrain while heavily loaded, but DARPA's planning an 18-month battery of practical tests to make sure that the LS3 can get the job done:
"Features to be tested and validated include the ability to carry 400lbs on a 20-mile trek in 24-hours without being refueled, and refinement of LS3’s vision sensors to track a specific individual or object, observe obstacles in its path and to autonomously make course corrections as needed. Also planned is the addition of “hearing” technology, enabling squad members to speak commands to LS3 such as “stop,” “sit” or “come here.” The robot also serves as a mobile auxiliary power source—troops may recharge batteries for radios and handheld devices while on patrol."
The overall goal here is for the LS3 to be able to behave functionally identically to a well-trained pack animal, albeit one that makes a lot of noise, eats gasoline, and can be used to recharge your iPod. If all goes well, the testing will culminate in a field exercise where the LS3 will embed itself with real live Marines. It'll be interesting to see how the soldiers will like a system like the LS3, and whether the robot will be able to keep up with the demands of a realistic mission.