Big Dog Robotic Dog/Mule

This thing has me thinking that the field of robotics is about to take a giant leap. It's got fantastic mechanics, and a walking/balancing algorithm that should win its programmers a Nobel Prize. It is truly amazing!

formatting link

-- Gordon

Reply to
Gordon McComb
Loading thread data ...

that video has been around for ?4? years...

one of the videos has footage of it JUMPING! about

5 feet distance.

It carries 150 pounds of cargo! Kick it and it doesn't fall over, it runs on unstable ground (rocks, snow, uphill loose rocks)

one of the most impressive robot videos I've seen.

Rich

Reply to
aiiadict

I may have linked to an older video, as I wanted one on a mainstream site. There is a new version of the robot, and new videos. But here's one of the new vids that's now on YouTube:

formatting link
The payload of the new version has been increased to 340 pounds, BTW. Even more impressive!

-- Gordon

snipped-for-privacy@gmail.com wrote:

Reply to
Gordon McComb

watching it slip around on the ice is awesome...

you can hear a 2 stroke gasoline engine running... I wonder if they run servos on the legs (gaso is generator spinner) or perhaps hydraulics (gaso is hydraulic pump spinner) What are the legs wrapped in? perhaps they cut the legs off a real dog, attached them, and want to cover it up so you cant see :-)

If I had one of those, I'd take it for walks and watch the little children scream in horror :-)

Rich

Reply to
aiiadict

This one's pretty cool, too:

formatting link
this one skitters about so much it is also cool:
formatting link
Can you imagine the psychological impact these things might have in dark jungles or deserts with the appropriate covering & sound effects ? Would either start or stop you from drinking !!! :-)

JCD

Reply to
pogo

--I'm waiting for the miniature one for Xmas or the medium-sized one for Battlebots, bwahaha! It'd make an awesome 'wheelchair' too, yes? Might have Kamen trumped with this one!

Reply to
steamer

I was really impressed with that new work as well.

However, one thing I noticed in that video is that it seemed to be using very different walking gaits in each segment. My assumption is that they are developing and testing different gait algorithms for different tasks. That's a fine thing to do, but stringing the different tests together on the video gives the illusion that the robot is better than it is - because it looks like it "knows" how to deal with all those different terrains by using different walking (or jumping) techniques. No doubt, they still have to work out how to combine multiple walking algorithms, all probably very different, into one general system that can adjust to the task at hand based on the situation. I suspect they still have a lot of work to do to make that happen.

Reply to
Curt Welch

Here is yet another video - showing it going uphill, downhill, and even running jumping and kicking up its heels at the end of the movie! COOL!

formatting link

Reply to
pogo

No, it looks like they have that figured out. I suspect the whole system is primarily gaitless - legs are viewed as an asset to be used to accomplish a goal. Gait is an emergent behavior.

Step through the sequence where it slips on ice and recovers, and pay attention to when the feet lift, when they slip and when they don't, and the primacy of slip control over balance control over foot sequencing over direction control. Don't think gait; think adaptive feedforward control. Read Raibert's old "Legged Robots that Balance" and my work from 1995.

Finally, someone is doing this right.

John Nagle Animats

Reply to
John Nagle

And in any case, as a "gait" it's not based on the anatomy of any animal on earth. The legs are in an unusual pushme/pullyou configuration.

It's also interesting that the legs never stop moving, even with the robot is keeping place.

-- Gordon

Reply to
Gordon McComb

I do agree that the "gait" algorithms are far from fixed sequences. It's clear they have a lot of very advanced adaptive balancing and movement at work (they aren't called Boston _Dynamics_ for nothing :)). The examples of them kicking the animal off balance show that nicely. And, as you say, the slipping on the ice is priceless in that it shows just how adaptive the system is.

But that doesn't explain the _extreme_ difference in behavior between the videos of it walking outside (where it never stops moving the legs and it is constantly prancing even when standing in place), and the video of it walking over the pile of concrete cinder blocks where it keeps 3 legs on the ground and only moves one at a time, and the video of it hopping and doing the jump at the end. That very much looks to me like three completely different locomotion algorithms. I can't imagine that their adaptive algorithm which keeps the feet moving would work very well at all on that pile of concrete blocks for example where the legs could get stuck between blocks or knock the blocks off balance when it trys to "dance" on them.

Reply to
Curt Welch

Quadrupeds have a range of different gaits they use for different situations, depending upon speed and terrain characteristics, ranging from slow creep to diagonal walk to trot to canters and a couple of types of gallop. Not all quads use the same range.

formatting link
The 1-legattatime is the creep gait, used widely by cats, but not so characteristic of dogs or horses, and is the most stable for going over rough terrain. The slower gaits differ mainly by relative leg timing, so it's not too difficult to change over between creep and diagonal walk or trot. The gallops OTOH are quite different leg sequencing,

As John indicated, Raibert [honcho at Boston Dynmaics] has been working on "dynamic" adaptive walking gaits since the early 1980s, since his time at the MIT leg lab. Lots of gimbals and gyros.

formatting link

=A0 =A0 =A0 =A0 =A0 =A0

formatting link
snipped-for-privacy@kcwc.com =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 = =A0 =A0 =A0 =A0 =A0
formatting link

Reply to
dan michaels

Big Dog looks a little strange, but in fact, the legs on quadrupeds are arranged in front-back mirror-symmetry fashion.

formatting link
Also, Boston Dynamics has had videos of BD on its site for a couple of years or so.

formatting link
Even back then, they were experimenting with slightly different leg arrangements with different #leg segments, as you can see in the original video, betwen the general walking scenes and the jumping scenes at the end.

Reply to
dan michaels

It's already here too.

formatting link

=A0 =A0 =A0 =A0 =A0 =A0

Reply to
dan michaels

Sorry, wrong link.

formatting link

Reply to
dan michaels

tho.. Gotta get on the waiting list I guess.. :-(

Reply to
steamer

Erp, I guess it was the symmetry of the legs that threw me. Elbows and knee-caps face one another.

-- Gordon

Reply to
Gordon McComb

Humans are built the same way. It's probably been a while since you were 2-YO, but try getting down on all fours and crawling on the floor. Knees hit elbows. You're doing the "Big Dog".

Later on, you can graduate to the "Time Warp". LOL.

formatting link

Reply to
dan michaels

Big Dog is unusually symmetrical, but that's probably a manufacturing economy. All four legs appear to use exactly the same parts. That's just good design. It's nicely worked out; the hydraulic cylinders and hoses are all inside the leg structures.

Foster-Miller, which makes the TALON and SWORDS military robots, apparently did the mechanical work.

John Nagle

Reply to
John Nagle

I totally agree with you Gordon. There will be huge changes in the next

10 years. I Live 35 minutes from this company. I can't even begin to tell you how badly I want to work there. I'd sweep the floors if I had to. ;-) I hope those guys read this thread.

Shawn

Gord> This thing has me thinking that the field of robotics is about to take a

Reply to
Shawn B.

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.