Glad to see your return on this project, it's one of the few high quality projects of its type here on KZfaq.

Love what you did with the joints and phalanges. Resin printing can be a real life saver.

Forever liking this project! So amazing to see the plans come together

Man I love this project, so happy you were able release another video for it. Thank you

Great design and video! Thanks for amazing content Will!!

Your bionics videos are easily the ones I'm waiting for the most on KZfaq! Please keep up the wonderful work!

Great job. It is a pleasure to see you work.

Amazing progression! Glad to see you back.

Fantastic work! I am about to restart my old project of a 3 fingered micro hand. It is very useful to see what difficulties you have faced.

I remember watching one of your videos when i started studying Biomedical Engineering, now i've graduated and still wish to make a proyect like yours Glad to see you working on this :)

I tried to built a hand like this once and it is insane how much better you did than me. It's super impressive.

I would personally recommend the tubing used on bicycles for their gearing and brake cables. already designed to do exactly what you need, and a good way to solve cable management if you have simply clip into the carpal and metacarpal regions. they come in spools you can cut to length and little metal caps so you just need to slot them in place endwise for them to maintain tension exactly where you need it. glad to see you back on this, looking forward to more RnD

What a dense video! Really great work and hopefully well worth taking time off work to focus on it :)

This is exactly the type of content I love on KZfaq. Amazing project.

I love it 🎉❤ hope to see more hands soon

omg ive been waiting for this for soooo long im glad to be here

I'm so happy to see more! I started building the previous design, am struggling to get the coronas into the joints. I want to use this hand with my Inmoov android arms. Been having a good bit of fun with it

Glad to see you return to this project!

Amazing progress❣️

Great work 👏. I am also designing a robotic arm and your design is really a great inspiration for me.

Looking good, keep the great work.

Awesome work!

Thanks for such a hard work! It will be very cool to use your project in some kind of power suit.

This is amazing work!

Excellent video!

I love it! Great job sir!

Uuuuh, another Upload! What a treat...

Wow Will, very cool, well done

So hyped to see this project again

This is amazing!! I aspire to be on your level one day!

Amazing sir love your work

Finally I've been awaiting your return ❤️

Very nice work.

i love seeing these updates

I think it is a wonderful idea. These arms are useful in dealing with dangerous materials inside a closed room and controlled remotely, such as explosive materials or toxic and acidic materials.

Бачив двох українців та аж стало тепло на душі що наші земляки бачать та підтримують такі проекти

Welcome back❤

Great to have you back on the project! If you ever want to compare notes, or work on something together hmu.

I love your work. I've been waiting for this for so long. I have a request if you could build a terminator version of the arm. If it isn't a trouble for you.

Was watching you in 2018, glad to see you have returned. The project is really great, especially in terms of freedom of motion. By the way, have you read the research of using sewing thread and make it deform under some heat application, the thread should be spinned multiple hundreds times (depends on length) and if you will apply cooper wire for heating, maybe you could use them instead of servos. Thank you!

Bowden tubing should be your friend. Run all your strings through it to give it room for slack without tangling on anything.

I"M SO PROUD OF YOU, WELCOME BACK !

i did the hand connection to an xt ibm back 90's ! used window plastic and stainless 1/8 " wire for pins! your fingers are exact as i did and i put a plastic plate on the top of the knuckl to prevent the fingers from going backwards! the hand griped a small 380 9mm dual ammo baritz and pulled the trigger without any problems !

Love your videos and I you make me want to design my own! Moving the servo sensor to the finger joints was genius by the way 👍

WELCOME BACK!!!

THIS IS WHAT IVE BEEN WAITING FOR!!!!!!

The robot makers in the world will be watching this waiting for your servicer. Very good

He’s back!!!

My first thought was also bowden cables like someone mentioned below but maybe bicycle shifter or brake cables could be cheaper and easier to get? The housings differ between them. Brake cable housing has a woven strong steel spiral. The shifter cables housing has steel wires running along the housing length. Might be worth experimenting with. 1,1mm is the smallest diameter on shifter cables. Great to see an update from you! Always inspiring and fact dense videos!

I support putting the servo drivers on the main PCB, partly because it's cleaner and partly because I like watching the servo's components get increasingly distributed through the hand.

try to use bowden cables for the cable joints, those will do what you need quite well with very high durability. Only issue is that they will need to be custom order sized due to design.

this is impressive, but one tip that I learnt the hard way: you only have two tendons per finger; the finger can flex so much because it's one tendon anchored at several points and it can flex independantly because tendons are malleable. you therefore only need 5 servos per finger, at least one for splay, and about two for the thumb: one for positioning along a curve, the other for flexing it like any other finger the CMC is basically an overdeveloped splay-muscle for a finger that's at 45* and in fact you can line your thumb with your finger for this exact reason. this alone means that the total servo count shouldn't exceed 8 for the hand, 2 for the wrist for something that is completely biomimetic. you can afford to simplify the main palm into just two halves, which should save on mechanical complexity, but a 3-part palm is closer to the real thing. for said tendons, bike cables would work well, and you can anchor the tube along the 1st and 2nd joints of each finger, with the cable itself being anchored on the finger. this way you have a compliant, durable and strong system. another thing to note, human palms reach farther than the knuckles due to them being flesh, which from the underside gives the illusion of having an extra set of joints in the fingers, also also, the shape of the palm is largely immutable save for the outer metacarpals of the ring and little finger which ever so slightly curve, though that is mostly caused by the compliant nature of having a frankly unnecessary amount of bones in the palm actually working on something similar myself, albeit drastically simplified and less "humanised" (it's just angular because I don't have fusion360 :p) either way uh... hope that I can help simplify things and my apologies if my knowledge of the series has gone a tad rusty, it has been a few years... EDIT: to clarify for understanding; by anchor, I mean like a thread passing through the eye of the needle: as the tendon is pulled, its shortening forces it against the structure, dragging the rest of the structure with it.

Great job, nice to see your progress! You could maybe use tubes made to guide brake cables on bicycles, they are made to work in compression. They might be slightly larger than your PTFE tubes however.

Excellent progress. I was wondering if you could route the tendon cables through parts of the hand structure? This would shorten the tubes and reduce the kinking. Or where several cables run parallel, 3D print a structure to encase the cables, reducing the length of tubes needed as well as keeping the cables tidy. Keep up the amazing work.

You could probably work on the routing of your Bowden tubes (fix them in place before and after articulations) to reduce the slack

Missed Your Work Sir

ooo caught the video right on time

Excellent

Any kind of stiffer cable housing would be great! Bicycle cable housing is meant to be very incompressible (especially for brake cables) but they might be too thick for your design. Good to checkout though, and maybe there are some engineering bowden cables that might be the right thing! Bicycles also sometimes have springs embedded into their brake assembly so you can't 'lock up' the wheel. Might provide some of that grip strength. Love this project, keep it up!

I still can't believe that massive government funded projects on bionics that have been around since the late 90s to early 2000s still haven't managed nearly as much accurate range of motion as this project made by a student. Looking forward to seeing this develop further

integrate the ptfe tubing through the prints up the wrist and down the fingers so that its prevented from scrunching and creating backlash

WILL YOURE BACK! Todays a good day soldiers

i have my own little project where I've also been experimenting a little with transferring motion through tubes. You should look into bike gearbox wires

This was such a good thing to see you working on this huge project again! 😊 Btw where did you get the nylon shoulder washers? Thanks a lot for the plugin idea, I always looked for an idea to send from Unity to serial... I can also recommend sending it to a server and then processing your data. I am using Python and running a Flask Server.

Note that you'll have to deal with cable stretch over time. Also, if you haven't encountered this yet, if you keep all the tendons tight to the skeleton, you'll soon find that when you make it make a fist, then bend the wrist, you'll have to further adjust the tendons in the fingers to give more or less cable length as you articulate the wrist. You'll need to account for that in your cable length adjustment calculations.. unless if your just using a closed loop system to just ensure the right amount of finger articulation while moving the wrist

I have seen many people using other kinds of motion capture technology, I think Manus gloves right now are the most used in the robotics field. i believe even Tesla is using these gloves for Optimus. I have tested them during an event, so far they are the most accurate motion capture gloves i found. even tho theyre a bit pricy, but i didnt find a better solution. Thank you for your videos, very interesting and informative!

I've recently started to use Chaservo HV-06s for my personal eye mechanisms. They're super small, but a bit expensive.

Need stiffer guide tubes for the cable tendons! Squishy tubes don't lend themselves well to transmitting much power. This is why bicycle brake cables have a metal coil that's then sealed in plastic to hold it together. Basically a long thin spring should work, you can wrap something around it or probably just find cable housing/cover designed for the application. There's all kinds!

Hi Will, I have written my master thesis on robotic hands and built a prototype using continuum robotics. Have a look at the DLR Awiwi hand. It is probably the most advanced hand out there. If you need any literature, let me know! Cheers

A very interesting design. Employing spring tension to the individual phalanges may resolve some of the jerkiness. But this may complicate your design, as the proper tension is a variable.

PTFE tubing with a way thinner internal diameter could help a lot also

Use flexor and extensor electrostatic motors to get rid of the tubes. And just use guide loops to keep things tidy. (forearm anatomy but in tech form) Think of a z-folded capacitor where the dielectric is rubber. Apply voltage and it contracts. No volts and it relaxes. Use one for the flexor another for the extensor.

Nice! I'm glad to see you ditched that bulky glove! Though, I feel like you're missing an opportunity with 3D printing... You could route out internal cavities for the wire management, and even ditch the PTFE tubing by running the cables internally in their own dedicated cavities as well. I understand that the length of each section would not be constant like it would with PTFE, but it would be predictable and calculatable for any given pose, and the arduino has plenty of capacity to calculate and interpolate the non constant cable distance.

sooo cool

Crazy!

Obviously building robotic hands at some point you want to program them to do amazing things. But the whole robot humanoid is another awesome goal. Then there's just so much to do. Think of the huge teams and resources that are going into creating essentially a robotic humanoid.

Your ptfe tubing looks really soft, almost like silicone tubing. The ptfe tubing in the bowden tube on my 3d printer is must more rigid. I think once you find better ptfe tubing which is more rigid and tighter around the cable then you'll see smoother movement. I know some sections need to be flexible so you'll probably have to transition between the two tubes in some places but for the straighest run from the forearm to the wrist it can be the more rigid one.

For servo management make it a full forearm the basic hand receives nerve impulses from as far back as the elbow a way so just continue to mimic natural and give yourself more room in that model should help some. Also elastic, spring, or even a secondary servo as a return to home position on the opposite side acting as a tendon with a dampener on it can help with smoothing the movement and making it feel more real for you.

Dremel would've made short work of cutting that tab off, using a metal cutting disk you could cut it right next to the gear itself with minor filing for cleanup after...

Dunno if this will be a useful suggestion, but there are some compliant finger designs on articles/research papers that might be worth a look. One example is "Mechanical Structures for Robotic Hands based on the “Compliant Mechanism” Concept" where the entire closing motion is done by a single pulling "string" attached to all three parts of the finger.

Great work 😊 Ptfe tubes … are they the same as in 3d printers? I know they work great under tension… never seen them in compression like the way you use them. Bodem tubes under compression are bike brakes and shifters, but they are metal.

what you are doing is very cool, but it will be even cooler to attach a neural network to this hand that could read brain signals using an Electroencephalography device and convert them into signals for the movement of actuators

THe ideal conduit material is continuous length extension spring - McMaster 9664K12. You could maybe stretch a bit out to gain some compliance, but that seems sketchier to me

Capricorn tube is what you use to upgrade an FDM 3d printer. Maybe that will help.

insane

You can avoid the ptfe buckling if you run it through spring housing.

Have you considered using electromyography sensors on the arm to control the hand? You could record the electric response from the muscles in your forearm, combined with the motion capture data to train an AI model to predict the hand position from the EMG signal alone.

I wonder how well a solenoid + spring assembly inside the finger would work compared to the servos. it probably would use a lot more power, because you'd need it to always be active. another solution might be to use basically a linear stepper* (i.e. a stepper motor but instead of being in a circle, the coils are in a line), which again is complex, but might give a compact system. (and you only need like 1cm-1/2inch of travel.) * basically what you'd do is a block of magnets facing opposite sides (i.e. if you look from the top going NSNSNS, and the bottom SNSNSN) with a pair of solenoids, one on top, the other on the bottom, with teeth on each pole, spaced the width of 2 magnets, and the poles being offset by one magnet. that makes it so to move one side you go {[+0],[0-],[-0],[0+],[+0]...} and repeat, and to move the other way, you do the opposite {[+0],[0+],[-0],[0-],[+0]...}. it should be relatively easy to cast some abrasive with epoxy in the shape of the needed file, and file down a bar of ferrite with a holder going back and forth and a vacuum, or the other option is to get some laser/waterjet cut magnetic steel sheets, or use a small desktop cnc (e.g. a rigid enough 3d printer with a motor attached to it) with an 0.8mm drill to cut the steel. for magnets you can use 1x10x5mm bar magnets. using microstepping (i.e. interpolate the values with a sinusoid) you should be able to get some fairly smooth motion. also you would probably be able to use a dedicated driver, but something like an uln 2003 would probably do the trick. though it's probably overkill, but it could be an interesting way to go about it and you don't have to worry about the transmission of power. something that could be interesting regardless is to use springs from clothespins for the spring grip, which means you only need tension in your transmission, and fixes the issue of stiffness in the sleeve.

instaed of having to pull the finger back up and pull then down. Could you use a small piece of spring steel to let the fingers come back up on their own and just use a cable to close them?

Don’t bad about paying for solutions, sometimes it’s needed and makes sense. It’s valuing someone else’s expertise!

This is great work. Springs with a smaller ptfe tube work pretty well! You can also route the cables primarily in straight lines on pulleys where you mantain constant loop length easily and then switch over to bowden tubes just where routing gets difficult. This can help increase stiffness and decrease friction. Out of curiosity, what is your day job?

Look into polyethylene fishing line muscles, it might help

could you resin print some cable channels? Maybe even just snap fit the PTFE tubes into the resin printed channels for support.

You are, figuratively, a machine.

For the tubing, you may be able to use bike shift/break housing instead, or take a note from their design and put your existing housing thru something to give it more rigidity, like a spring with the same i.d. as the o.d. of the tubing, however, if sized wrong, the spring may also introduce increased internal friction, in which case, going with an existing product will probably be the better choice.

Since you have your potentiometers in the finger joins anyway, isn't it sufficient to constrain the cable paths all the way to the motors instead of using floating guide tubes ? Sure, by having all the joins be influences by the bigger ones it caps the speed you can run the big ones at unless you manage to make the cables run tight to the pivot points to not affect the joins down the line too much.

This is really interesting! You can improve precision of the servos by using magnetic encoders instead of potentiometers (this requires a new control board though). Also, would using BLDC motors with FOC drivers be viable in your design? If it works, you could set virtual boundaries and virtual tension instead of using springs in the motion transmission. Great work!! Looking forward to updates!

If the servos for the fingers were on the back of the wrist instead of in the forearm, would that eliminate the need to have the compressive tubes?

Amazing work! You must have incredible patience to do such a project as this. Did I hear that right? You are using Arduino(s) to control this hand? If so, may I ask why you wouldn't use ESP32s for this project? Faster, Dual CPUs, more memory, built in WiFi (or peer-to-peer) communications, etc? Perhaps I didn't hear that right. Personally, I've been deving on Arduinos for years, but only a year or 2 ago I got into ESP32s and just fell in love with these. So much more robust. Anyway, lovely job there.

Great