Quora answer on Boston dynamic's robots

[Bill Weiler]

https://www.quora.com/What-kind-of-learning-algorithms-are-used-on-Boston-Dynamics-robots

Bill W.

[A J]

I wish that I could afford a SpotMini but maybe we can be building our own versions in few years!

My question is how Sequential Composition compares to how the animals in nature drive

their body motion. Some animals can move with the herd a few hours after birth.

But it seems to make sense because the arms and legs have finite range of motions that

they can articulate to execute a maneuver (range, speed, CG ...).

Is this something that can be implemented with Raps Pi 3 ?

https://www.cres.mse.tum.de/fileadmin/w00brq/www/people/hackl/MED_Hackl_et_al_2008_1.pdf

On Wed, Nov 7, 2018 at 10:44 AM Bill Weiler <bill...@gmail.com> wrote:

https://www.quora.com/What-kind-of-learning-algorithms-are-used-on-Boston-Dynamics-robots

Bill W.

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[Chris Albertson]

This is an open question.   We don't know how we learnto walk, except it is clear that today's "machine learning" is not how it works in animals.

It seems to be burned into our genetics. 

If you want to build a walking robot you do not need to invetnew science.  LOTS has been written and there is even open source software.   The biggest problem for a hobbyest is the cost of the high performance motors and motordrivers. Gets good enough power to weight ration is hard and costs a lot.   Biston Dynanics uses hydralics and a centralized pump driven by an elecric motor.  They say that the key part that took about a decade to develope as the computer controled hydralic valve.

Their newest robots use an integrated structure, for example the hydraalic fuid line is a long hole drilled through a leg and the ave is machined in the structure.  There is not "frame".  The motors and such are part of the surpot structure.  This save a lot of weight

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Chris Albertson
Redondo Beach, California

[Taylor Alexander]

I believe the legs on their biped are actually 3D printed titanium, with the bores for the hydraulics printed in the part. They're apparently absurdly expensive. This is what my friend who worked at Boston Dynamics told me.

[Richard Chycoski]

When you live on the defence budget, 'virtual unobtanium' is an everyday source material. ;-)

There might be some hope for those of us who don't have access to blank government cheques - we also don't have to design something aimed at surviving the battle field.

Decades ago I did some work for a small engineering company in North Vancouver that was building geophysical test probes to measure the permeability of the ground under earthen dams. It was about a 20 foot long tube with lots of rechargeable batteries and a pump with the *smallest* 3 hp electric motor that I'd ever seen. They apparently came from Boeing and were originally meant to operate one of the mechanisms on the wings. The motor was about 1-1/2 inches in diameter and maybe 3 inches long. They couldn't have been too expensive because the engineer that owned the place was, shall we say, more than thrifty? (I repaired the main motor control for a Pisces submarine that he had supplied for them - yet another reason you'd never get me down in one of those! Two *cheap* pots linked with a bent paper clip!)

Anybody up in Seattle near the Boeing plant (or know of someone who is)? They used to have a surplus sales area, don't know if they still do...

[But that Boston Dynamics walking, parkour-playing robot *IS* awesome!!!]

- Richard, VE7CVS

[Chris Albertson]

On Sat, Nov 10, 2018 at 5:23 PM Richard Chycoski <ve7...@gmail.com> wrote:

When you live on the defence budget, 'virtual unobtanium' is an everyday source material. ;-)

It is a self-funded project.  No "defence budget".

You can buy an 1,800 watt motor that fits in the palm of you hand for about $80 now.    I think 1,800W is mote than 3HP.   Moters with this kind of size and preformance is easy to get.  I have abut 12 motors here that are about 250 watts and 1" diametrer x 1" tall.  I paid $8 each for them.   Is that about 1/2 HP

What has happened to allow very high performance at low cost is the development of very powerful magnets and also now computers cheap enough to comutate three phase brashless moters and MOSFETS with practiaclly zero on-resistance.    Put all those together and we get flying drones and Tesla cars.

Back to the robot.   I had read that the structure and mechanicals were integrated, that does save a lot of weight and assembly time.   This is a technique that even hobbyests can do now using free tools but with a hobby budget yuo are prining plastic not titanium.

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[Walt Perko]

Hi,

 

Brushless motors typically are much less horse power than the KWs imply.  A 1.8KW brushed or brushless motor is probably between 1hp and 1.5hp.  Check with your local R/C flying friends, they can point you to the best bang for your buck on a good strong motor with the power requirements you need. 

 

Also, there are several motor calculators that will help you find the motor you need … some calculators even come from the motor manufacturers to better match their motors real properties. 

 

 

 

==============================================================================================
C U L8r,  °|°  Walt Perko  °|°        "Kids ... teach them the good stuff, and they still learn the bad stuff on their own."

http://www.R2Pv1.com/  RoboGuts™ Intelligent content for 3D printing making S.T.E.A.M. education better, easier and more affordable 

 

Experiments to learn how to use various Electronic Components, Structured Computer Programming, Phonemes for Speech &Song in any language, and Art.

                         "The World Needs a New Economic Model"
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            Sent from the Cyber7

[Richard Chycoski]

For "defence budget" I was referring to the Boston Dynamics project. :-)

1800 W is slightly less than 3 HP (2.4) but in the same neighbourhood, and $80 is a great price!

746W/HP, so the 250W motors are about 1/3 HP - still impressive!

For 3D metal printing, this looks intriguing:

https://newatlas.com/desktop-metal-3d-printing/50654/

Not home-cheap yet, but at $120K for a metal 3D printer, it might be something that could bring 3D metal printing to a "corner store" (or Internet service) near you, for those critical parts that just  have to be metal but not practical to mill.

There are some plastic-carrier metals that you can print on a hobbyist machine and then sinter, but the results that I've see so far are more practical for jewelry than for robots.

I'm not up to building a bi- (or quadra-) pedal robot yet, I'll stick to wheels for now - but I'd like to tackle something that walks eventually. Probably four or six legs first, two is a huge challenge.

- Richard, VE7CVS