Boston Dynamics Takes WildCat Outside


[Boston Dynamics] has released a video of their latest robot, which means it’s time to go hide in bed before this thing comes to get us. The new video features WildCat, which is apparently the evolution of the Cheetah robot we saw last year. Cheetah was an indoor cat, tethered by power, data, and hydraulic lines while running on a treadmill. WildCat has been released to terrorize people explore the great outdoors

Reminiscent of the early videos of BigDog, WildCat is currently powered by an internal combustion engine. The engine drives a hydraulic system, which then actuates the robot’s legs and front/rear pods. The beauty of a system like this is that switching to an electric motor is simple – just replace the IC engine. While we’re sure this would make a much more stealthy cat, weight and run time could be issues. Moving the power system onboard has also slowed down WildCat a bit. Cheetah was able to reach 28 MPH while WildCat can only muster 16 MPH.

WildCat is part of DARPA’s maximum mobility and manipulation program. The research appears to be focused on improving the gaits the robot uses to move at various speeds. The video highlights both bounding and galloping.  Slo-mo sections show all four of WildCat’s legs leaving the ground, which is the suspension phase of a classic gallop gait. Control isn’t perfect yet, as WildCat tumbles at one point in the video.  It gets right back up though – ready for more.

62 thoughts on “Boston Dynamics Takes WildCat Outside

    1. I was thinking the same thing. But, they are smaller than 4 strokes, and the higher rpm probably gives the hydraulic system higher pressure with less volume output. I’m not a hydraulic or mechanical engineer though, so it’s only my best guess…

          1. For testing purposes I’d guess it doesn’t really matter too much. They probably need a light weight powerplant to run the thing. Next versions will be better, thats for sure.

    1. Or rather, the front legs are in backwards. It has no brakes because the legs works like levers that buckle underneath the body instead of digging into the ground.

      But that might be by intention, because Boston Dynamics robots appear to employ a simplified balancing method where only two diagonally opposing legs are ever allowed to push down at the same time. That way the mass distribution/momentum of the robot is quickly deduced from the way in which the resulting seesaw pivots, and the point where the next leg should land is obvious.

      If three legs were touching the ground, the situation would become more complex and require more sensors and more machine learning and adaptation to keep balance. That’s why their robots never walk – they always trot or hop no matter how slow they’re moving.

      1. Right on–it lacks the heel & long metatarsus (foot bone) of a cat’s rear legs, but the rear knee hinges in the normal direction..

        It will be interesting to see if they reverse the front “elbow” joint in the future.

    2. There’s a very good reason why the legs are oriented the way they are. By having the hip link of the legs angled forward rather than backwards, the lower segment of the leg naturally swings backwards (thus shortening the leg) as the hip swings forward. If it were oriented the other way, the robot’s hydraulics would have to fight the leg’s natural tendency to extend when the hip swings forward. In terms of running speed and efficiency, it’s advantageous to have leg’s first link angled forward.

      Working in this lab:
      Hearing the Boston dynamics founder talking about it at NERC 2013

  1. I agree, Either it runs backwards, or the legs are on backwards. Cool stopping technique. Hey! I have an idea! Bring that thing over and intimidate the new neighbors constantly barking dogs. Hmm. I have some cable ties, maybe I can solve the problem myself. (Told you I was a brat.)

    1. I just can’t possibly see why they wouldn’t eventually power it by a tiny jet.

      Problems may be that they lack the expertise in that area, getting common land vehicle military fuel sources to do the job may be hard, and most importantly: maintenance. Knowledge and materials to fix two-strokes are everywhere, jets not so much, turboshafts, especially tiny ones might as well be alien technology to many people.

  2. Boston Dynamics makes by far, hands down, the creepiest robotics videos in the world. There are other awesome walking/running robots out there, particularly in Japan, but noone is so brazenly Skynet-in-your-face, all military colors all the time, as Boston Dynamics. When you look at the results of their awesome engineering work, there’s not even a shadow of a doubt what these are for. Well, indeed, DARPA-funded and all. Just makes me curious, is there any civilian application for these walking machines?

    Also, why Wild Cat? It’s more like Seabiscuit, both by looks/behavior as well as purpose. Unless they plan on actually mounting a weapon on it?

    1. >>”Unless they plan on actually mounting a weapon on it?”

      I guess they already did and don’t show off with. It’s a question of years when Petman jr. or wild cat x will kill a human being.

  3. I wonder if the thing has a remote kill switch, or if every time they take it out the lab there’s a danger that the last they’ll see of it is it galloping off into the distance.

  4. I want to see this thing with a chainsaw attached to the front, chasing some screaming guy down an alley. That would make the sound of the two stroke engine sound legit. And it’s kinda close to what this is being developed for…

    Thinking about it, an all terrain moving robot with a chainsaw would be pretty useful to cut trees at steep hills and such. Cutting half rotten trees in dangerous terrain is still pretty prone for accidents.

  5. The writeup says ‘ It gets right back up though’, but thats’ the part that makes this so poor compared to big dog, it did NOT get up again, they just cut the video to a time when they winched it back up.

    1. Neither did the big dog. In the video where they show it rolling down into the ground, they cut and changed the camera angle just the same, showing the robot getting up but not the efforts they went through to fix it in the mean while.

  6. They make the most amazing robots, but i can’t help thinking that they’re, excuse the pun, barking up the wrong tree. The legs are reversed, it has no neck or flexible legs and no tail. The thing is rigid and pitch/yaw seems controlled only by forward momentum and slanting. I know, i know algorithms taking all this into account would be… insane. The fact that they can even do what they do is amazing. I’m just worried that they will hit a wall at some point with the design they have now. But hey, R/D i guess :) iterations, iterations.

  7. “Control isn’t perfect yet, as WildCat tumbles at one point in the video. It gets right back up though – ready for more.”

    See, I saw that as the WildCat doing a quick 180 maneuver as it looks like it’s in the original start position again.

  8. As cool as this looks and as interesting as i find the build to be..
    I can’t help but to think how the novelty of such a creature would quickly wear off once you find yourself being chased down though an open field by a weaponized version of this.

    Military funding and darpa projects don’t exactly have a history of creating things for the betterment of humanity.

    Pain, suffering, misery and bloodshed are their typical results.

    1. “Military funding and darpa projects don’t exactly have a history of creating things for the betterment of humanity.”
      Yeah. Look where this whole “Internet” thing has gone…

  9. Get me a waiver to sign and a saddle and I’ll ride it. I’ll even bring my own saddle.

    If there’s a security guard from BD reading this: C’mon, we know there’s some footage of around 5pm on a Saturday out back behind the dumpsters of someone riding this thing. Share it please?

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