Holy Hopping Humanoids, Batman!

Just a little follow-up on an earlier thread, where it seemed that some posters believed the Robo-One robots were mere remote-controlled stock
kits with little of interest to offer...
http://www.robots-dreams.com/2006/09/roboone_10_neut.html
This is a humanoid robot, built (not from a kit!) and programmed by high school students in Japan, that can do repeated "rabbit hops" while turning in midair and maintaining its balance as it lands.
It's very impressive, in my opinion. These Robo-One competitions not only inspire students, but I think a good argument can be made that they're actually driving progress in small humanoid robotics.
They're also wildly popular, and growing more so every year -- a trend that has started to catch on here in the U.S. My prediction is that in a few years, Robo-One competitions will dwarf all other robot competitions in the U.S. as well, and all the cool kids will be trying to compete. :)
Best, - Joe
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Yeah, it looks neat. However, I didn't see it making anything that looked like activate balance movements in the jump so I don't think it is actually keeping itself balanced in any sense. It seems to just be a wind-up toy with large enough feet that it doesn't fall over when executing pre-programmed walk and jump movements. It could I guess have some feet sensors that it's reacting to in such subtle ways that it doesn't really show in the motions.

Could be. Humanoid robots have a certain appeal to them that is missing in the other robots.

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Curt Welch wrote:
...

It looks like the move is mostly canned, but when the robot settles, it does seem to have some compliance. You'll see it wobble a bit from side to side with both feet in contact with the ground. There's some feedback there.
If you can get force feedback, you can do so much more. This has been known in industrial robotics for two decades, and it's taken way too long to filter down to the hobbyist level. The dumb output-only R/C servo interface has held back the whole field. Finally, things are moving beyond that.
                John Nagle
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Yeah, good point. Just some force feedback data from active servos would give it a lot to work with without any other sensors.
Looking at the video again more carefully, I think I do see it reacting in ways with the legs that doesn't seem to be caned when it lands. But it's hard to tell whether the reaction is the result of some spring built into the legs and joints (which would be reasonable for a bot designed to jump like that to reduce stress on the servos), or whether it's the result of some active feedback algorithms at work. A think a simple PID controller with a lower gear ratio than typical hobby servos system could be using the feedback to create a similar effect and it would only need an encoder to get position feedback and not force feedback.
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Curt Welch wrote:

NeutrinoX probably has some active balancing system that works during normal operation, and also stabilizes it when it lands after jumping.
I've tried getting some of my walkers to jump - or rather lift part of the frame off the ground - but the standard servos are just too slow to accomplish this. They just don't move fast enough to give the frame enough momentum to lift-off. Neutrino probably has the fastest digital servos as a start. Then, you notice it uses every body joint, from flipping the arms upwards to bending and straightening at ankles, knees, and hips, to produce upward momentum. The addition of springs to the joints to give an additional boost would help a lot.
Regards my walkers, I was thinking about the possiblity of implementing some sort of run-gallop type gait, which is the only way to get speed beyond a fast trot. To do this requires lifting the front-end completely off the ground and springing forward. The only way I figured I might get this to happen is to add some sort of springs to the legs, and use stored energy in the springs for the jump. But haven't gotten that far yet.
You'll notice that animals in general don't get all of their lift-off energy from muscle activation, but probably 1/2 of it comes from energy stored in elastic parts, like tendons, ligaments, and mechanical part of muscle fibers.
Regards other robots that could lift off, you can take a look at Scout I + II. It gets its boost from springs and proper resonance timing ...
http://www.cim.mcgill.ca/~arlweb/scouti/scout1.htm http://www.cim.mcgill.ca/~arlweb/scoutii/
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dan michaels wrote:

Humans recover about 60-70% of the energy from stride to stride in the springyness of muscles. For some of the specialized running animals, like a cheetah, it's above 90%.
Almost all the research robots that run have energy storage in springs. (ASIMO doesn't, but ASIMO's "run" has about 1cm of ground clearance in the "flight" phase, which is very short.)
The problem with springs is excess flexibility makes it hard to do stable stuff, like standing. An actuator followed by a spring isn't enough. Nobody has a really good mechanical solution to this. It can be done with pneumatics; if you can control the pressure of both sides of a pneumatic cylinder separately, you have a spring with a variable spring constant and a variable zero point, which is what you want. There's a robot at CWRU that works that way. See
http://biorobots.cwru.edu/projects/robot3/robot3.htm
The Stanford 4-legged running machine (Waldron) has a leg supported by a spring, plus a motor that winds up a cable to tension the spring. The motor can release the cable very fast, faster than it can tighten it, so you can wind up a leg and then, at a chosen time, release it. That gets you takeoff power for running and jumping. When the leg is partly wound up, with the motor pulling against the spring, it's relatively stiff, so the thing can stand without wobbling. See
http://www.stanford.edu/group/locolab
Some combination of motor, spring, and maybe a clutch or brake is probably the way to go, but the mechanical designs need to improve.
                John Nagle                 Animats
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It has two gyro sensors and an accelerometer. The analog sensor signals are processed by the the robots RCB-3 controller and used to control multiple servos - usually four or six hip/leg/foot servos in a parallelogram fashion.
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Thanks for the info, Lem. You seem to have more info on some of these bots than I've seen posted anywhere. A great feature for your site would be, now and then, a detailed report on a particular robot -- what sort of servos it uses, what sensors it has, how it's done in recent competitions (if any), anything the builder's especially proud of, whatever you can find out. That would really be interesting and helpful for a newbie like me.
In addition to this great jumper, I'd love to learn more about this red "900" (or is it "006") robot shown in these images:
<http://www.flickr.com/photos/95721430@N00/245293733/in/set-7215759428758 6087/>
For example, what's inside those neat little cubes at the joints, and why do there appear to be no wires connecting them?!?
Whatever you do, please keep up the good work with robots-dreams... it's become one of my best resources for information on current hobby robotics!
Best, - Joe
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Sheesh, what a newbie -- that bot is none other than the famous OmniZero! Don't I feel like a schmuck. Anyway, I'd still love to see a detailed profile of it, with as much detail as you can dig up.
Best, - Joe
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You're very welcome. It's my pleasure.

Well, it helps that I've lived here and been involved in the technology business in Japan since late 1982.

I agree, and will try to expand and enhance Robots Dreams to include as much of that as time permits. Still, there are only so many hours in the day... !:')

As you figured out in your later post, that's the latest version of OmniZero. It's number '006' in the ROBO-ONE official database.

If you're talking about the knee joints, those are servos. Maeda likes the double servo type approach since it responds much more rapidly than the more common single servo designs.
As for 'no wires' - they're there, it's just that Maeda is a perfectionist and takes the time to dress and route things properly. He's definitely a 'Pro', but then working for Vstone he should be.
Later,
Lem
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Very cool!
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I'm a newbie, with a question about RC servos.
Do servos use power when they are stationary? Do they use power all the time?
If so, is this a big problem?
-- Martin Sondergaard, London, UK.
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Martin Sondergaard wrote:

If there's no mechanical load on the servo, and it's not moving, the current drops to a very low level. If the servo is pushing against a load and can't make it to the desired position, it will draw current even when stationary. This is likely to happen in leg servos for robots, since some force has to be applied to oppose gravity.
            John Nagle
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Martin Sondergaard wrote:

If you want a servo to stop the best way is to no longer send it pulses. It then uses virtually no current. Note that some serial servo controllers are designed to always send pulses. I'd avoid those actually, and go with a microcontroller or servo controller that allows you to stop sending the pulses.
As John notes if the servo is not under load, even with pulses continuously sent the current draw is low ... usually just a couple milliamps.
-- Gordon
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Thank you for your answers, John and Gordon.
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London.
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