/robowaifu/ - DIY Robot Wives

Advancing robotics to a point where anime catgrill meidos in tiny miniskirts are a reality.

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Hand Development Robowaifu Technician 07/28/2020 (Tue) 04:43:19 No.4577
Since we have no thread for hands, I'm now opening one. Aside the AI, it might be the most difficult thing to archive. For now, we could at least collect and discuss some ideas about it. There's Will Cogleys channel: https://www.youtube.com/c/WillCogley - he's on his way to build a motor driven biomimetic hand. It's for humans eventually, so not much space for sensors right now, which can't be wired to humans anyways. He knows a lot about hands and we might be able to learn from it, and build something (even much smaller) for our waifus. Redesign: https://youtu.be/-zqZ-izx-7w More: https://youtu.be/3pmj-ESVuoU Finger prototype: https://youtu.be/MxbX9iKGd6w CMC joint: https://youtu.be/DqGq5mnd_n4 I think the thread about sensoric skin >>242 is closely related to this topic, because it will be difficult to build a hand which also has good sensory input. We'll have to come up with some very small GelSight-like sensors. F3 hand (pneumatic) https://youtu.be/JPTnVLJH4SY https://youtu.be/j_8Pvzj-HdQ Festo hand (pneumatic) https://youtu.be/5e0F14IRxVc Thread >>417 is about Prosthetics, especially Open Prosthetics. This can be relevant to some degree. However, the constraints are different. We might have more space in the forearms, but we want marvelous sensors in the hands and have to connect them to the body. The thread about actuators is related: >>406 and the discussion in R&D General starting here >>1627 is a lot about artificial muscles. My own concept in my mind for the most ambitious models so far is the following: We have no space to waste. We might try to use light canals and LEDs inside to indicate bending. We'll probably need to use PCBs for transport of current incl data while acting as part of the bone. We'll probably need connectors between the parts which transport current without bending cables, eg cylinders with layers out of different materials where some of them are conductive. We should try to use Will Cogleys files as foundation, but since we might want to only build the bones out of hard material we might need to do it in metal to go smaller. This metal might be something expensive, like Titanium. We'll need tools for fine mechanics and such skills. I also think air pressure might be usefull to help open the hands fast, of course in combo with strings. I haven't thought about the actuators in the forearms a lot, by now. That's it for now, I'm really curious about the ideas for the premium models, but even more so for the cheap and then maybe even smaller waifus.
>>4877 should've posted this along with.
>>4878 BTW, please not the quite generous direct 'shaft' of open volume available with this 4-rod tensegrity design. I intend to mount a central tube down this space as a guideway for running Bowden cables out to the extremities all the way from the proximal major ball & socket joints located at the torso.
>>4879 >please note* (check the shadow directly below the framework)
The guy improving the InMoov design I mentioned here >>4876 moved on in a similar direction than Will Cogley with his new hand, embedding little motors in the hand, using SLA printed pulleys. https://youtu.be/3DNVadMs5tE Though, it needs to be noted that they are doing it because they might want to build a prothesis, which has other constraints than a robot arm. We should look at it, but also keep in mind that we have other priorities.
>>4883 That looks like a pretty promising approach actually.
>>4884 Thinks so too, though we might be able to combine it with Bowden cables and servos in the wrist later on. Just checked, I can turn my similar little motor in both directions if there's no torque applied.
>>4885 I think I missed description of the motors themselves. Can you fill us in Anon?
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>>4887 Minute 2:34 and min 4. Micro metal geared motors: I've got the one on the pic for idk 1.50-3.50€, I guess around 2€. But I only bought one for testing and don't have the u-shaped one. He talks about SLS printed pulleys, but the one he has, can also be bought on Ali in sets with gears for 2€, some of mine are on the other pic.
>>4876 >>4863 some guy posted your board on g i'm just driving by here but I'll drop you a hint hyperboloids for the metacarpals
>>4892 >hyperboloids for the metacarpals heh thanks for the hint, driveby-kun. :^) https://en.wikipedia.org/wiki/Hyperboloid https://en.wikipedia.org/wiki/Metacarpal_bones My presumption is that Driveby-Anon intends us to understand a geometric behavior of the metacarpals. The tendons connect both above and below, and the particular curve they exhibit gives them a leverage advantage during gripping motion, for example.
>>4892 >>4893 Someone was claiming in this thread on /g/ the human hand was mostly made out of those and this was patented till 2040. Patents need to have a certain amount of innovation, though. Also, I'd need to look into these vids about joints if this true, and then it might still not be the best way.
>>4902 I see. Hmm, I don't think it's particularly problematic. There's far, far too much prior art in this arena (literally going back for millennia) to be in any way enforceable.
> Will Cogley Progress intensifies: https://youtu.be/99RzNBQF6g8 It's of course quite to big for now, but I like where this goes. > Skeletal prototype with windows to look into it, to see how well the gears are moving. > MG996R Servos from Tower Pro bought on AliExpress > Ultrahigh molecular weight Polyethylene, PTFE cube Github: https://github.com/ikkalebob/NM-bionic-hand/
>>4945 Thank you for keeping us updated on his progress. The man is a real talent at this type of engineering and is obviously quite motivated as well. Good stuff, Anon.
>>4891 Someone having an opinion on which amount of RPM I should pick, when I order some of those motors? I guesstimated for the thumb it might move 2-4cm on the joint, the shaft of the motor has 3mm or so, which makes 30mm per second with 10 RPM, which is 3cm. So I think I'll really stay on the absolute low end of the scale. Any objections?
>>4974 >So I think I'll really stay on the absolute low end of the scale. Any objections? It's simply a trade-off like all engineering is between velocity and torque. If you need more power, go slower. If you need more speed, expect less rotational force.
>>4975 Sure, I was already aware of that. Don't want the fingers move to slow, however. Then again, I can replace the motors later anyways, so I probably shouldn't overthink this. I'll take something around 10-15 RPM, but not 5, and not 30.
>>4976 Sounds good. As always, Test, Iterate, Improve.
>>4883 There's a new vid of his hand with the microgear motors: https://youtu.be/Zi-s_RQNokw Sadly he emphasizes that he thinks it's only possible to print the parts for the hand with a SLS printer, which is out of reach for most people. He's getting the parts from some paid service bc also hasn't one himself. As inspiration the approach might still be very relevant. I'm saying for a while hands are going to be very difficult.
5018 >SLS printer A guy built his own? https://www.instructables.com/id/DIY-SLS-3D-Printer/ Also, that's a high-end goal to exactly reproduce a prosthetic-capable hand. We'll be able to make due with far less refined designs for our robowaifus for years. It's a good goal to work towards, but we'll be able to create good (enough) hands much sooner.
>>5026 Fascinating, but it seems to be abandoned. Even with 5x5 cm this would be great, but it would need at least to work with PLA or better Nylon. He used tea with 95% sugar or alternatively Stearin, which is some kind of fat that melts at 48-50C. However, I'm quite sure we'll get around needing some SLS printer for the hands. He used it for potentiometers, same as Will Cogley in his model. These seem to fail after a while anyways, so other sensors might be better. Also, with some little changes it might not be necessary, and resin printers might be good enough, or even FDM and standard parts which we can buy.
>>5043 Well, maybe someone with some resources can set up a good SLS printer and provide prints as a service bureau. Maybe someone already does this?
>>5018 Thanks Anon. I like his design in general. Quite simple and to the point. I particularly like how he thought ahead about ease-of-assembly in at least a couple of different points, and overall I think it seems a fairly good design approach for the fingers. Very utilitarian and not too expensive by the looks of it. Did he give any cost estimates for the out-sourced parts printing?
>>5045 > Cost estimate No, or I haven't seen it yet. Costs might not be the problem, if it's already finished. But for development it might be relevant, especially considering possible additional shipping costs and the delay.
>>5043 >Also, with some little changes it might not be necessary, and resin printers might be good enough, or even FDM and standard parts which we can buy. Sounds interesting. Have anything specific in mind, Anon?
>>5047 No, or I don't remember something specific, but we can print small with FDM: https://youtu.be/gN7QMhBzd4E https://youtu.be/LHg9phNSCEY
>>5048 >0.15mm wow i didn't know there were even nozzles that small, looks almost like resin printing. looks like it takes some mods needed to make it work.
A normal human hand is the ultimate multi-use tool. It isn't that hard to replicate one specific feature of a human hand, what seems impossible is to cram the feature list into the small space of one hand (plus forearm). How about this: Picture an android with two hands that look the same, but are different underneath. The wish list of features is split between the hands in some way (for example, one hand can be strong & the other one precise). As long as both hands working together can achieve what you want them to achieve, this is almost as good as each hand having the full feature set. Heck, when doing this you might find yourself suddenly with some extra space left and throw in a magnet or suction-cup function.
>>5592 Good idea. Noted, but I hope we can do better. Btw, if no one answers to a posting, it doesn't mean no one is interested in it or won't appreciate it, just that we shouldn't flood the forum with praises to each others ideas.
potentially-related xposts >>699 >>704 >>705
Some tangentially related news from japan. It's a kind of hand-holding simulator: https://archive.vn/7c2LR Unfortunately, there's not much info available, apart from a two page pdf written in moonrunes
>>6489 i can't see it behind cuckflare. mind posting a link and i can see if wayback has it.
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Has anyone here investigated the Shadow Hand very much? Seems interesting and I like the way the 'tendons' actually travel up through the wrist into the hand itself.
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Found this image from a news article promoting a project using a company's elastomeric touch sensors. > I thought the design of the fingers were interesting, if a little overdone. www.extremetech.com/extreme/293610-mit-created-a-robot-that-maps-3d-objects-by-touch
Parallel Cable driven Anthropomorphic Robotic Hand: https://youtu.be/GzXvqFWgIs4
>>8632 Wow, thanks Anon! This is exactly the kind of approach that's been swirling around in my head for a few months (though mine have been mostly about the overall armature itself). It's particularly gratifying to see the idea working so well in something so detailed and technical as this human hand mimic. I'd be interested to see some numbers on strength and grip testing with it.
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>>8632 This is too good to leave just on yt.
>>8637 This looks excellent...but I always have suspicions about actual functionality when they crop so much out of the video and only show the hand lying down - not attached to a moving arm. What about all the servos that presumably drive those cables? That's gotta add considerable weight and size to the end of the arm. Would be nice to see in greater detail.
>>8651 >Would be nice to see in greater detail. Agreed. I'm too busy to dig around and try to get more details on their project work atm. Hopefully more information will be forthcoming here soon.
This guy https://youtu.be/qqBjBY4zf8I is still working on his DARA robot. It's a male robot, but might be useful to keep track of it. I mentioned him before in >>5327 bc he has some files on Thingyverse.
>>8700 Please keep us updated if you find this man makes a nice breakthrough that might help us out here. I like the lateral motion he's able to achieve thus far. Very life-like.
This hand design by a prosthetic company seems pretty useful: https://www.youtube.com/watch?v=B-f0egEgKms They changed the shape of the hand to make it easier to grip objects.
>>9690 Yes, looks like a decent, reasonably rugged design Anon. Thanks for bringing it to our attention. BTW, anon started a prosthetics thread here as well. Seems on-topic. >>417
Open file (1.79 MB 480x360 ohayou.webm)
I've been looking for attempts at playing piano with bionic hands. Someone made a rudimentary robot 11 years ago but they barely count as hands since they can only press the white keys. https://www.youtube.com/watch?v=IwuiOwZrzCM The closest thing I could find was this military prosthetic: https://www.youtube.com/watch?v=DP677lA_DEA And this robot typing on a keyboard which is pretty cool: https://www.youtube.com/watch?v=Nek_yvvLRdQ Are servos not fast or strong enough to make quick movements or is it more of a control problem? Could larger servos be stored in the chest and operate the hands with cables using pulleys?
>>10072 Bionic prosthetics normally don't have sensors. For building a robot playing piano you would probably want that. Btw, I just got my heat sensitve plastics for making hands skeletons like therobotstudio did (16€/kg). Here: https://youtu.be/bVDneXZ_YfQ - related (various vids): >>9362 >>9471 Some of the hands related vids: https://youtu.be/kWeJyduvhwA https://youtu.be/CfB8Mrh1dSI https://youtu.be/1PYMT1U8qiM https://youtu.be/tO3B_OyyqmQ https://youtu.be/tZ-ouSmt5gw
>>10072 >Could larger servos be stored in the chest and operate the hands with cables using pulleys? Not that anon, but you have a sound design idea there Anon. If we can figure out a way to entirely remove the weight and volume of servos out on the arms, then that will help everything move along better for us, physics-wise (and therefore, agility & energy-consumption wise). It will take some creativity to figure out how to do this, but using some form of cable-only approach in all the extremities will pay off in spades for us all.
>related (>>10179)

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