Virtual Sphere Rolling Joint Robot Arm (DYNAMIXEL + OpenRB-150)

[@Skyentific]

In order to finance my KZbin channel and my projects, I am starting the consultation in robotics. So if you would like to ask me questions about my builds (or about your projects) you can do this through my website ( www.skyentific.com/book-online ). This service is not cheap, because I would like to limit it (with lower prices I would have to do this all day long, and I would not have time for projects/KZbin). And of course, I cannot guarantee that I will be able to help you during this consultation, but I will do my best.

[@vip8877]

Я даже не сразу врубился, что видео на английском языке)) Русская речь на английском языке))) мне понравилось, спасибо!

[@StefsEngineering]

The inverted movement reminds me of GLADOS. Cool concept, thanks for sharing! Remember, the cake is a lie!

[@notepadgamer]

Watching these videos is definitely a highlight of my day. Always impressive seeing 3D printing used in such a versatile manner

[@markTheWoodlands]

This is a fantastic way to teach the concept of adding degrees of freedom incrementally to an initially simpler setup.

[@Rudmin]

The biggest drawback of the “quaternion joint” is that it’s not actually kinematically defined with true rigid bodies. It relies on tiny amounts of joint slop and elastic deformation to act as a joint.

[@abhiwins123]

One of the chief drawback from mechanical point of view is that at specific angle in 3d coordinate, there will be excessive torque needed for delta movement. Similar to knuckle joint strains at 45°

[@pauljs75]

If it were constrained by an extra armature, it seems it could be used as a constant velocity joint. But again it may be limited by torque loading... However I wonder if that could be worked from the other direction by using a CV-joint design that handles torque well as a robotic armature if it's not constrained like it would be on a vehicle drive line?

[@abhiwins123]

@@pauljs75 I liked the counter idea, its an idea worth exploring.

[@keixsy]

could someone explain this but for dummys? (me)

[@gamerfortynine]

@@keixsy The design allows angles with lots of stress against specific joints. I.E. too many hard materials to flex and distribute the stress accross the entire structure.

[@JinKee]

@@pauljs75 look up the Thompson Coupling from Australia.

[@tariq7772]

Lol, I spent an entire weekend in Fusion 360 recently "inventing" this very same basic joint structure. It goes without saying that there is nothing new under the sun and brighter minds have usually tread the same ground. Keep up the great work and thanks for sharing!!

[@dm5rkt]

Also have a look at Mark Rosheim's Omni Wrist 3 mechanism.

[@tariq7772]

@@dm5rkt Thanks! I just uploaded the concept I worked up. It moves in 3DOF, but would require linear actuation/artificial muscles to control. Not sure how practical. kzbin.info/www/bejne/pYCmYXmuorJnjaM . If you have seen my concept worked out further somewhere, let me know. I am not trying to be original, lol. Just want a compact solution for a "shoulder" joint. Of course my joint suffers from multiple positional limitations.

[@michaelrichey8516]

Your test at 17:00 is the money shot! That's the one I was waiting for - stable platform rotating is sweet! Well done!

[@carlosmontgomery4178]

Fractal design! A larger one for the upper arm. Smaller one of the wrist. Even smaller still for a set of fingers!

[@morphoice]

Literally the most fascinating mechanism I've seen in ages.

[@DanielRhoades4122]

That has got to be the absolute coolest robot arm I have ever seen!!! Now I want to print my own, lol. Thanks for sharing.

[@jpsousa4]

I watched a video about rolling joints and didn't even learn how to roll a single one. Kidding, this is a really cool mechanism. Thanks for putting this video together! :D

[@PunakiviAddikti]

This is a great demonstration of inverse kinematics as well.

[@GameTL]

Thank you for the effort in explaining the concept in the beginnning.

[@RafaelSobral]

Valeu!

[@ps6k4trk33]

Very nice project, very interesting for solar's panel purchasing applications, congrats

[@ronalddriskill7360]

This is really high quality and informative. People like you make the internet awesome. Subscribed!

[@strangeluck]

Fascinating point you made that because you're using three motors for two degrees of motion you can use the servos to eliminate backlash. Also like how this design lends itself to easy cabling. Very cool. Thanks for sharing.

[@markusbuchholz3518]

Thank you so much for depicting your wonderful project. Your work and effort are oustanding. Your movies have been providing excitement and inspiration for so many years. Thank you again!

[@evanrinehart2733]

Thanks

[@vell0cet517]

I'd love to see how you worked out the inverse kinematics for this thing. That would be a great video on its own. These spherical parallel manipulators are just so mesmerizing to watch. They remind me of a delta 3d printer in some ways. Beauty and engineering. Well done. I think it'd be cool to stick a 360 lidar on the top of one and use it for slam mapping in 3d.

[@aaronthomas8834]

This is awesome! It’s like a mechanical elephant trunk. It’d be awesome to see 10 of these joined together getting progressively smaller by a factor of 1.618. I’d love to see this in 6061 aluminum with the proper power and servos. This arm would be extremely helpful in space on the ISS or on a moon base. Imagine it on an automated gantry that can move in x y and z. It could put together entire habitats and move parts etc.

[@mattdrat3087]

This, scaled down, would make for a fantastic animatronic puppet!

[@gendragongfly]

There is another benefit to this design, modularity. Your first 2 axis have the same configuration and the same hardware as the second 2 axis and so on.

[@hardundware]

Wow. Very nice work 😳💪🤟👌

[@missingpartsclub]

It's an interesting concept. Idk if you've seen what naver labs with the ambidex used this joint for, but very similar application. If you decide to expand on this project you might try changing the drive ratio from 2:1 to 4:1. That would increase your avaliable torque but at the cost of speed. Great work as always. Keep it up!

[@Дмитрий_Алкогольевич]

Hello, my favourite cyborg. 😄

[@Razzreal_plays]

Spoiler : I watched this whole video, that robot does not roll a joint. Much sad, very disappoint.

[@JinKee]

Add fingers in the next update

[@redbugg99]

Exactly it is a stupid idea ... and so unpractical.

[@THEOGGUNSHOW]

😂😂😂😂 😢 🚬 +🤖 = 🚭

[@adonisengineering5508]

Yes, where is the virtual rolling of a joint we are all here for? If AI can do anything, it could also do what low IQ people do.

[@roboage1027]

Very interesting design for the wrist joint of the robotic arm. I wish, I saw this video, before starting making my own robot.

[@Ron_DeForest]

This is amazing. Craziest joints I’ve ever seen.

[@r5bc]

Can't wait for further development on this arm. Please keep up the good work

[@scottjackson2812]

Really cool! You could add another DOF by putting the base on a rotating axis.

[@tracygilmore7983]

I would wonder about worm drive from continuous rotation servo motor ,bit harder to code , but better ratio and no backlash. Can't figure out if a compression spring rather than the carbon rod would be better - maybe on the outside? Give it that old Tobor look, .

[@Nobody-Nowhere]

joint rolling robot? finally a robot with an actual purpose

[@porkrinds9572]

Perhaps the use of worm/screw type gears on the motor side would work better? Also have the added benefit of reduced play in the driven structures to act as a better braking mechanism...?

[@robinchazen159]

I was thinking the same thing, and drive them using cables (like a Dremel flex shaft) so all the motors are in the base. That will also cut down the weight of stage 2 and 3 drastically.

[@davenarisotto3674]

That's a very cool robot arm! It looks elegant

[@ThisIsToolman]

Beautiful mechanism. Rigidity/stability will be the biggest challenge.

[@lightbatmen]

Для увеличения жёсткости стоит добавить продольные рёбра жёсткости.

[@StephenMattison66]

TYVM for the brilliant lapel mic, your audio is superb!

[@jach1969]

Thankkk uu for all your sharing with us ❤️🌹❤️

[@ilkero1067]

Dear Dynamixel, hope you are reading this. I am already a fan of your products, using them for years now. It is great to see you support one of my favorite channels. Would be happier if you support this channel even more!!

[@skaramicke]

I would love to see this configuration done in aluminium and with greatly increased gear ratios. It feels like it could be 1:100 instead of 1:2, and still have usable top speed.

[@maxgood42]

Then mount it on tracks with a FLIR camera and let it roam around the streets at 3am .

[@ionutdimache3509]

You talk about harmonic drive? ;)

[@porkrinds9572]

Also looks like this could work as a sort of CV Joint with extended angular working range for delivering rotational force. Would need some serious reinforced alloy arms and tight tolerance bearings though. Absolutely love your videos, sir!

[@carlosmontgomery4178]

I asked the same question.

[@pauljs75]

Ditto on that. CV joints and "virtual sphere rolling joints" solve the same problem, just for different applications. And given the variation in existing CV joints, modifying one of those may suit this purpose in a more robust fashion.

[@PCBWay]

One more epic, thanks so much for bringing us this 👍

[@Smytjf11]

Need... more... degrees of freedom... This has been great, thanks for letting us into your dev process 😁

[@lyomon9981]

these are really diferent ways to make joints !!! amazing sir

[@leofernekes343]

What an interesting design- thanks for making this video.

[@LabGecko]

Great work! Seeing this illustrates just how much of an engineering leap it is to go from this to factory level robotics to Tony Stark style concepts.

[@ObsequiousV4]

Definitely one of the coolest channels on youtube

[@moshe778950101]

More gear ratio or possible worm and gear setup will ease on the servos. Would be lovely to see the maths involved.

[@Paul-rs4gd]

I sure hope Robotis gives you the extra 3 motors. I love the organic nature of the movements - it reminds me of an elephants trunk.

[@kristiansims]

Really cool to look at, though it seems a bit inefficient to use three motors for two degrees of freedom at each stage. I wonder if there’s a way to recover that with a rotating DOF between stages that could come from a sum of all the motors or something with a differential like that.

[@merlinjim]

Yeah he actually missed in his explanation that you can rotate+translate Z by rotating all servos the same direction. So the 3rd DOF is not something a traditional roboticist considers a DOF since its a mix of two DOFs. The 3 motors do all contribute their power to motion so having a 3rd one is not inefficient even if you constrain the calculations to not rotate the platform

[@DrJeff-]

Brilliant, as usual. Love watching your work in Robotics!

[@juliusfucik4011]

Instantly subscribed. Love this! Maybe you could use high speed DC motors with a very low gearing. Then for positioning you could use other concepts; perhaps include orientation sensors or some other kind of feedback.

[@CharlesVanNoland]

Beautiful and magnificent. I can't believe I've never seen anything beyond the literal rolling joint - with the cables/strings and also only with one axis. These multi-axis rolling joints are awesome. Great stuff!

[@elrinstrongsword]

I love your work and would love to see this with CNC tool steel or titanium construction and capstan drives scaled up to enormous strength

[@themarsoff]

интересно у вас получается объяснять 👍

[@maxgood42]

Add the ‘Eye Ball’ to this, ….. “Its Alive”… And it’s a thing of beauty. 😎

[@qwertyzxaszc6323]

That mechanism would also be great for the spine of a robot, giving it a lot of mobility. Also, I wonder if this mechanism would be better if it is driven by cables rather than gears.

[@mountainlion4853]

Love it, love it, love it. You are doing a great service 😊

[@MrTrilbe]

I think some mass could be removed via scalloping the edges and putting in fullers on any flat parts, also by skeletonizing the bases, it might help

[@juliusfucik4011]

It will help greatly. The amount of torque from extending the mass is large.

[@runedyrting8476]

Very interesting! I am sure there are many uses for such a link.

[@critical_always]

3D printers can give you a super power because you can explore all kinds of ideas relatively quickly.

[@juliusfucik4011]

True, but design and printing this in several iterations with a single printer takes weeks if not months. But of course, that is part of the fun too

[@critical_always]

@@juliusfucik4011 yes very true. It's the design and CAD skills that matter. I do everything in open source OPENSCAD as I refuse to commit my designs to rent software.

[@pitot1988]

This will be a nice mechanism for telescope array to track the sky the same time and moving more fluidly than conventional slewing

[@nob5000]

i like it! im sure it will lead to something very unique and useful

[@grendelum]

here i was expecting a robot arm to roll a joint… still very neat ;¬)

[@danielb.2873]

Very nice design, love it

[@maeve615]

I wonder how this would hold up as a joint for rotary power transmission.

[@Clark-Mills]

The tri-arms act like springs adding to the oscillations; maybe stiffer material or a more braced micro-in-fill of triangles?

[@kartikeyawalia]

Hi, I have been following your content and it has been very interesting and informative. Just a suggestion for this design- at every stage you just need 2 actuators instead of 3 as according to my understanding any 2 of the arms are active and the 3rd is kinematically coupled. It will reduce the weight of the stages and might help the robot dynamics.

[@xaytana]

In theory you only need two motors per joint, in practical application you need three for holding strength. There's also reasons why tentacle-like arms do not approach their design like this, but rather use air bladders or wire actuators that have a larger motor in the base, with a more simplistic design that uses a flexible non-compressible spine between the actuation discs; not to mention higher arm rigidity and less complexity in these models. Though the alternate design does require three actuators, or four depending on design, due to actuation not being linked to the spine itself as it is in this model. The older iterations of the LIMS2 AMBIDEX wrist used a similar model to the alternative, having actuation be separated from the spine via wire actuators, though they used a mechanical spine of the same design as the segments shown here; the key point here is that the spine is not directly linked to the actuators. This design realistically works for only one to two segments do to its downfalls, whereas the more optimal design can go for many more segments. I have a feeling, due to the downfalls of this design, that this project would become a sunken cost fallacy even for the best designers, there's just no good way to optimize all the problems, whereas an alternative provides less issues from the start.

[@kartikeyawalia]

@@xaytana I agree with your point. Another design that can be an alternative for a quaternion joint used here is an Omni Wrist by Ross Hime Designs Inc.

[@jeanbalcaen1917]

very organic moves, a joy too see :-)

[@NathansBarelyUploads]

Women are going to love this

[@tomsko863]

Add in a "Centering Spring". Just a piece of spring steel or coiled compression wire in the middle to give a restoring force to the assembly. Also look at joysticks and how they do it.

[@bluddywulf6796]

Try printing with a mesh structure infill instead of solid. it will help with rigidity.

[@vishvraval4079]

Use a seperate servo motor drive for better current distribution. Here voltage is not the problem, current is , current plays important role in providing torque.

[@dantesmith3664]

wow, thats pretty cool. nice work

[@MrJelliefish]

I'd like to see the two section configuration with suction cups to climb a wall end over end!

[@DestianLight]

Looks cool and very clever

[@pavelarhipov668]

Incredible... Only yesterday I thought about 2-dof joint realization..

[@C0MPLEXITY]

Thank you for explaining how it works. I hope you see success soon

[@mirceapaulmuresan]

Very cool! Now that you have DYNAMIXEL servos it would be cool to see a comparison between them and the GYEMS motors and maybe other servos as well :)

[@justin_704]

if you use elastic bands on opposite side of tension it will react as muscle tissue and provide the resistance you need ;)

[@rivvion]

This video is absolutely amazing!

[@sed6]

Brilliant design and execution!

[@ozzietradie6514]

joint looks cool

[@jordanco]

Awesome job man!

[@aalaal171]

Hi sir, amazing work! Can you please make the next video of strength test to see how and how much weight it can lift and move it around? TQ

[@marcfruchtman9473]

Thank you for this very interesting video.

[@jasoncreech4486]

You always have great videos. This is a cool and unique design. Great work and thanks for sharing it with us.

[@Infoneson]

Extremely cool concept and design. I could definitely see this design in usage for deep sea/space exploration scenarios.

[@adamtan4234]

Can you please share the research paper you used for calculation and modeling the rolling joint? Would love to have a look at it

[@justthinkingthoughts]

Just an idea, without undetstanding the geometrical operation in detail ... Couple the three axis with gears and drive two of them and let the third free spinning. Backlash elimination might bite the grass but you could use worm screws for the axis for better torque... Maybe the third axis needs a brake for holding

[@WikiSnapper]

That is really cool!

[@mists_of_time]

What an amazing project!

[@henrimilo1]

Perfect for sun tracking!

[@MrFranklitalien]

keep up the awesome work your stuff never ceases to inspire :)

[@Bloomio95]

I would love to see this concept in its full potential! So with higher quality parts for less wobbling and more powerful actuators. Great work! I´m planning a fully mechanical arm with 3-4 joints. Any suggestions on how to control the speed of the gears (the resistance) fully mechanically?

[@clydecox2108]

Very cool robot

[@Skyentific]

Thank you a lot!

[@Skyentific]

Link to the controller (Super New!!!) OpenRB-150: bit.ly/3PJdQDZ

[@glowytheglowbug]

niceeeeeeeeee

[@dc37009]

ARD-BOT-EMB~PO ~~$25-OpenRB-150-Arduino Compatible DYNAMIXEL controller - KZbin ! Very niceeeeeee ! ...Thanks awesome vid !

[@NiCeDarox]

have you tried to replace the gears between the plates with worm gears to make it more stiff? The worm gear can move the upper gear but the upper gear can't move the worm.

[@Derian_De_Grey]

Йоур инглиш из вери гуд😄👍

[@vmened]

Hi, i found new way to build reductor with planetar gear and ratio 354:1. May be it will be interesting for you kzbin.info/www/bejne/o5zdnoWfd62rmbs

[@Aleks_Z]

I would use worm gears on motors, they are slower, but you'd get more torque and less tension on motors, since you have ability to "lock" them in place