advancements on the spider pully leg design

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goaty

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advancements on the spider pully leg design
« on: October 17, 2019, 07:17:41 AM »
(mostly for HopefullySomething…)

YAW-YAW-YAW …  still works.

It may make the bot a little weird to look at,  but Ive made it easier to put together.
Ive redone my little pully leg design, and I found the softbody bag isn't really whats making it work, its actually the bracing itself which is supporting the rotation which is the important member.  So its hollow bones with the tendons going up the bone, and I worked out something really cool,  and its the fact that a yaw rotation could be a pitch or a roll, just depends on the orientation.  So in-between these yaw rotations theres actually a twist that happens which will change the orientation of the rotation (just 90 degree changes will change a yaw into a pitch or roll) that make a ROLL-YAW-PITCH action for the leg,  and hopefully the bot given a proper hip like rotation set may be able to jump off the ground better like a grasshopper!

The other cool thing about it,  is I probably have to make the tendons a little fatter and the tunnel a bit biffer… and then you can cut this one like a ginger bread man - just flat, and the twists and bends will change the yaws into pitch and roll.    So one lazer cutting and you've got the bot, as long as u can cut out the tendons with it.
Might be a bit kinky, but with the right plastic it could still pull ok. hen to assemble it, I imagine I just have to brace it with some triangle frames to get it to the right 90 degree bends it needs to transform the yaws to pitch and roll.

So if you need to make manufacturing easier for yourself, its just a puzzle away.



To power it,  one solenoid per pulley wire.  do the motor driver however you want,  but ive got something quite zany in mind for that as well,  but it might not come to fruition, but have to wait and see.
« Last Edit: October 17, 2019, 11:33:48 AM by goaty »

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Hopefully Something

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Re: advancements on the spider pully leg design
« Reply #1 on: October 17, 2019, 04:50:04 PM »
Even simpler!  O0 Could use the same design for fingers. The question is how do you generate enough torque with a short distance from the axis of rotation. We could have big strong hinges (or could it be ball and socket... but you'd need twelve wires and fifty solenoids) or we could use short double acting air pistons, one for two opposite strings, so you automatically reel in any slack. But with a hinge joint the idea is to rotate the leg at the base, so it can push forward or backward? So if it starts in neutral the strings will only ever twist 45 degrees forward or backwards, seems doable but the strings won't be at full tension in neutral then, maybe some strong springs/ elastics would help keep the system responsive and the joints seated with constant pressure.

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goaty

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Re: advancements on the spider pully leg design
« Reply #2 on: October 17, 2019, 06:05:47 PM »
Thanks for lookin'  gives me such great joy.  :)  U get the visualization,  the bones sorta just pull attach into each other.
Its cool having the solenoids in the body, not putting the power at the joint, even tho I do like those robots as well.
Fingers yes,  I figure a hand is basicly a spider on the end of both forearms. hehe.

Definitely might be a torque problem,  but u could sacrifice the hand idea, and for a big leg you could span it out further I guess and it would still be useable as a knee, probably not a finger tho.

About the tension thing, I still think itll work because isn't equal tension no matter what the position? It just means u don't give it any slack, If the motor driver Is wanting an absolute position, itll fight for it no matter where the joint is.

You could swap half the solenoids for a return spring as well If theres too many for your liking, and you guage it for how powerful the coil is.
So, some time in the near future, when I get up to it,  ive got to chop it out of a sheet of plastic and go give it a real test,  and see what actually happens.

Thanks for checkin' it out!!!  :=)  two noses!!


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Hopefully Something

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Re: advancements on the spider pully leg design
« Reply #3 on: October 17, 2019, 06:39:53 PM »
I figure a hand is basicly a spider on the end of both forearms. hehe.
:rhubarb:  :vamoosh:
About the tension thing, I still think it'll work because isn't equal tension no matter what the position?

If you twist the leg at the base, to rotate the angle at which it pushes off the ground, then the tendons will twist and increase the tension. Like a trebuchet, unless you are visualizing the mechanism differently. Maybe the twisty section should have a convergence of tendons into a small area?

Thanks for checkin' it out!!!  :=)  two noses!!

Shire! Baggins!

EDIT: You know, as in, Naz-gûl sniffing out the solution to AI... Two are better than one. But we'd the "good" Nazgûl in this scenario eg "One code to make them all, one code to wake them, one code to ring them all, and round this record take them." More of a jolly thing..
« Last Edit: October 20, 2019, 04:11:51 AM by Hopefully Something »

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goaty

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Re: advancements on the spider pully leg design
« Reply #4 on: October 17, 2019, 09:00:22 PM »
about the backforce from the ground->

There is a back force that the motors have to take, and ur saying itll slack the joint, and if the machine hasn't got a way of detecting it then it wont be able to correct for it.   yep,  maybe your right. im not sure if that's what you meant, but there might be a problem there...

Actually the wire that pulls detects, but the other wire slacks -  so I have to detect it off one end.  but there is an issue,  that its only detectable off one of the capacitors not them both,  and they don't actually add up 100%, because the pulley slacks...   so ill have to think about it.
« Last Edit: October 17, 2019, 09:21:17 PM by goaty »

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Hopefully Something

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Re: advancements on the spider pully leg design
« Reply #5 on: October 17, 2019, 11:07:30 PM »
Yeah you're right it would be possible to take that effect into consideration if using a dedicated actuator for each string. You could rig it to maintain force instead of distance.  Just wouldn't work with a double acting piston, that's when you'd need some slack.

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goaty

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Re: advancements on the spider pully leg design
« Reply #6 on: October 18, 2019, 12:14:47 AM »
We are seeing this thing in 2 different fricken ways.    2 different knowledge bases.
Not so simple after all,  im trying to make some robot that only costs 5c for me to make it, but theres issues...

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Hopefully Something

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Re: advancements on the spider pully leg design
« Reply #7 on: October 18, 2019, 02:06:48 AM »
We are discovering the reason why everyone isn't making quality cheap stuff. I did the math and right now one of my cubes costs $54.50 in materials  :uglystupid2:. Between quality, cost, and time, you can only choose two. You can have high quality & cheap, but that requires lots of time. You can have cheap, and fast, but the quality will suffer. You can have high quality and fast, but its gonna cost a lot. I like the first option the best for now. I'm at a dead end with my designs as well, trying to make molds with embedded magnets so I don't have to glue everything, but the dimensions are just slightly in favor of everything imploding and getting stuck together when it's 99% done. And I'm looking for an alternative for microprocessors, because they cost so much. Some kind of circuit could be enough to operate a single neuron, like a full bridge rectifier to automatically correct positive/negative and something to change the resistance between synapses (maybe light dependent so the neural net could be grown by a traditional computer). Like Christmas lights around a living tree guiding the photosynthesis! Hehe just got this idea! OK now I'm happy! Thanks goaty! 

Hey look, someone already figured out how to make a controllable led cube:

https://www.youtube.com/watch?v=f1YNyQqbiF0

Now if this could be lowered into a physical neural network like a uranium rod then I think you could get a cognitive reaction going.
« Last Edit: October 18, 2019, 04:37:18 AM by Hopefully Something »

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Art

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Re: advancements on the spider pully leg design
« Reply #8 on: October 18, 2019, 04:03:07 PM »
Cool!

I was waiting for the AI to take over in the form of a 3D head, kind of like the one in iRobot with Will Smith.

The link to their site doesn't work. Enter this: http://www.seekway.com.cn/html/en/index.php?ac=article&at=list&tid=488
In the world of AI, it's the thought that counts!

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goaty

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Re: advancements on the spider pully leg design
« Reply #9 on: October 19, 2019, 02:43:10 PM »
Hopefully,  you may be able to afford your 1000 cube design but you have to get bulk prices.  it may not be as unaffordable as you think,  but im not sure where to go to get the more professional bulk price, youll have to shop around harder.
« Last Edit: October 19, 2019, 03:17:20 PM by goaty »

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goaty

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Re: advancements on the spider pully leg design
« Reply #10 on: October 19, 2019, 03:09:58 PM »
For that slack back driving problem, In the "motor driver", make sure it either full pulls, or it just pulls enough to collect the slack for the wire, but not rotate the joint.


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LOCKSUIT

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Re: advancements on the spider pully leg design
« Reply #11 on: October 21, 2019, 08:26:38 PM »
"
Between quality, cost, and time, you can only choose two.

You can have high quality & cheap,    but that requires lots of time.
You can have cheap, and fast,    but the quality will suffer.
You can have high quality and fast,    but its gonna cost a lot.
"

The highest quality thing in the highest quantity will come in long due time, at a high cost :) ..... the result is the lowest cost lol.
Emergent

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Korrelan

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Hopefully Something

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Re: advancements on the spider pully leg design
« Reply #13 on: October 22, 2019, 02:05:28 AM »
Wawe they done did a smart. Robots using this could probably run very efficiently by adding a counterweight and spinning their legs in full circles, like wheels with one spoke.

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goaty

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Re: advancements on the spider pully leg design
« Reply #14 on: October 22, 2019, 04:41:24 PM »
"
Between quality, cost, and time, you can only choose two.

You can have high quality & cheap,    but that requires lots of time.
You can have cheap, and fast,    but the quality will suffer.
You can have high quality and fast,    but its gonna cost a lot.
"

The highest quality thing in the highest quantity will come in long due time, at a high cost :) ..... the result is the lowest cost lol.

if you don't count time or intellectual difficulty,  it costs 0c forever after.

 


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