Bipeds

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doc222
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Bipeds

Post by doc222 »

Bipeds, love'em -hate'em. Not sure how many have worked on them but every now and then I have been asked, "how the X2 rotation joints worked". My last X-2 was built to complete a task of climbing steps in a simple way. Since each leg had 3dof and 1 dof to shift all that mass of batteries to keep a balance point. I s about as simple as a Biped in function I could build and complete the task.

I have made one update to the planitary system. Since the main drive input to the sytem had 1 8z in the center of the palitary that gettes loaded at 4 angles. But each main gear has 2 8z contacting the LT(lagre turtables). This that means that 1 8z withe 4 contact points was loaded with 8-8z in the end. The new system is one brick widder but doubles the power out by useing two 8z at center and all other gears doubled up. This Super joint now was enough power out to give all 8z's to the LT full power without the issue if over loaded that center single gear could strip out. This is weight at a very high working load, the new one I have yet to break it but I think now the 8-8z at the LT could skip if over loaded, these gears are now held by 8 axles with stops as well these seem to improve this area of contact as well.

These pics are of a basic Single Semi planitary. To make a Double just double it up.
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Right now X-2 is in rebuild to now have 5dof legs each. This adds 2dof to each leg that is a leaning function(for more advanced ankle and hip side to side flex. This has been a huge issue in makeing an assemby that can take loads and be flexible, compact and have this working load to handle these extreme loads.

At first i was making just more planitarys though this worked it adds ALOT of weight, was not compact enough. Linear rams would be a better choice, but issues have been reprorted with our Lego La's. Fernnellii would be an option but have been out of stock a long time, perhasp they have an issue as well? So i found that at the ankles I may use 4or8 Lego La. I have two on a side now but i can see a 4 ram working there better. The hips will crush a Lego La. So I built a Linear ram of tecnic parts. 9x5x11 This ram is a redundant system as well 4 drive and 4 idle(the idle could be powered as well doubling its power as well to 8. Twin/twin worms drive at 72:1. mounted in the hip.

This was an atempt at all geared 10dof To tall, gangilly and much to heavy(notice single planitary's here)
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My Technic Ram for hip lean.
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So now here is One leg completed to the HIp area and a ankle.
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So If this works out It will shift weight in a more Human way and much more complex as well.
"Anyone who has never made a mistake has never tried anything new."
Albert Einstein
schodet
Posts: 139
Joined: 29 Sep 2010, 11:21
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Re: Bipeds

Post by schodet »

I don't know what to say... whaou!
LEGO things http://ni.fr.eu.org/lego/ - NXT Improved Firmware (GCC) http://nxt-firmware.ni.fr.eu.org/ - Other robots http://apbteam.org
maybe-nxt-time
Posts: 3
Joined: 13 Oct 2010, 07:41

Re: Bipeds

Post by maybe-nxt-time »

genius... gotta love complexity! :D
aswin0
Posts: 201
Joined: 29 Sep 2010, 06:58

Re: Bipeds

Post by aswin0 »

Wow,

If I ever loose a limb I know who to contact.

Nice peace of work, can't wait to see it in action.
My blog: nxttime.wordpress.com
alpharhino
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Re: Bipeds

Post by alpharhino »

Yeah but if I ever go to Doc it will be for a metal bionic leg, not a lego one! :lol:
I reject your reality and substitute my own. - Adam Savage
mightor
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Re: Bipeds

Post by mightor »

xrsfisher wrote:Yeah but if I ever go to Doc it will be for a metal bionic leg, not a lego one! :lol:
Who wouldn't want a Lego bionic leg that you can rebuild into a bicycle?

- Xander
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helumpago
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Joined: 30 Sep 2010, 00:17
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Re: Bipeds

Post by helumpago »

mightor wrote: Who wouldn't want a Lego bionic leg that you can rebuild into a bicycle?

- Xander
ha! When Muntoo finally takes over the world, that'd be useful for a quick get away!
(you can't catch me, I'm the ginger bread man!)
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doc222
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Re: Bipeds

Post by doc222 »

I would be way to tempted to take the Leg apart to complet that next project!!
"Anyone who has never made a mistake has never tried anything new."
Albert Einstein
doc222
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Re: Bipeds

Post by doc222 »

Parts came in and the build seems good. Now the much harder part. Programming a 6 dof legged robot was rather simple though still alot of work.

X-2.5 has 10 dof leggs with added hip and ankle leaning this should be a rather long work to program. With so much freedom of movment comes many varibles.
This bot should be able to mimic a human gate. Plans include Climbing steps and walking. Mechaincaly it has many improvments over the last version. Each articulation is almost 2x stronger now with the new double planitary system. The leaning systems uses 4 of the new Linear rams from lego at the feet. Two of my new home made linear rams at the hips.

Completed build, need a bit of clean up of all those wires but it seems to work well in early testing
Image

Lego linear rams lean at the ankle, redisigned the feet this works very well.
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Side view
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Doc"Bipeds are a sickness"
"Anyone who has never made a mistake has never tried anything new."
Albert Einstein
gloomyandy
Posts: 323
Joined: 29 Sep 2010, 05:03

Re: Bipeds

Post by gloomyandy »

Oh my... So how many motors/actuators does this have now? How are you controlling them all? Would love to see some more details... These really is very cool!
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