You've never seen the Robot Joint like this one!
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- เผยแพร่เมื่อ 24 มิ.ย. 2024
- Here I present unusual Robotic Joint. Actually this is kind of cable driven reducer. The great advantage is that it has zero backlash. I am not planning to use it for my robot, but I think that it could be interesting for you.
Special thanks to my special Patrons: Wesley Corp, RobotDigg Shanghai and Pierre Freyssinet!
Links used:
LIMS2: • LIMS2-AMBIDEX High-... , • LIMS2-AMBIDEX Whole Bo... , • LIMS2-AMBIDEX mechan...
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#Robotics #Robot #RobotArm - วิทยาศาสตร์และเทคโนโลยี
I would like to point out another advantage of the beautiful system that you designed: The torque is equal over the entire travel of the joint. This can be hugely beneficial in robotics where knowledge of the force is required.
Your comment caught my attention because I've been playing around with robotic joint actuators, 3D-printing some of the examples representing different types (planetary, wave, cycloid, etc.) I think I understand what you mean, but can you explain briefly why other types may not deliver equal torque over the range? Are you speaking specifically about cable-driven types? So far, I have built planetary and cycloid for 4 axes, and now I have been looking various types of capstan/cable drive systems, (hoping) to select the "right" one...
@@mbunds hey bro I can tell you why. It is because this is a form of mechanical power transfer. Where you transfer power from one location (motor/actuator) to another location in the system. The reason why he said torque is equal over the entire travel of the joint is because with other methods of power transfer such as the 4bar/2bar mechanism, have an inherent disadvantage due to the effect of the lever arm on the output torque of the joint. the torque changes base on the angle of the lever arm causing you to have more torque at a lower degree angle and lower torque at a higher degree angle.
@@mbunds traditional chain pulley belt system you see in automotive are big huge assembly power transfering system. You basically getting the same advantage as a belt pulley which reduces the overall size profile of the system.
Would be cool to see it in action with a motor and some weight lifting tests. as always, great work!
Before the video:
After the video: pulleh
hahaha XD I was reading the intro some comments , but with the first "Pulleh". I paid attention to the video
Dude .. not cool. You had me saying polleh after every time he does!
poleh
zeh pulleh!
I think James Bruton would be very interested in this joint!
Joints always elicit interest...lol
Single servo dog leg!
Sadly I don't think he does. There was a comment on last week's video about someone suggesting this, and his reply was a typical 'I'm not doing that because I don't need it' kind of reply. I like James and his content, but he comes off extremely arrogant in his own comments, sometimes even in his own videos. Maybe he'll look into it in the future if QDD doesn't work well for his compliant dog projects, though this kind of actuator is exactly what he's looking for with his search for a compliant leg mechanism.
The lab that developed LIMS2 also developed a finger joint with a single wire and some springs, where the springs return the finger to a neutral position when the wire actuator is relaxed. Something like that mechanism could be adapted to be a passive compliant foot, with an encoder on the drum for positioning purposes, spring on the foot would keep the foot securely planted no matter what the terrain type is, and a simple torsion spring on the drum itself would always keep the wire in tension. Of course, the foot would need to be redesigned to have a cam profile, that way the passive system actuates while the foot is stepping, but that's nothing more than some additional math in the programming as your foot position changes slightly as the leg steps down. I also believe this system, a passive actuator with a way to sense positioning, is _exactly_ what James is looking for with a compliant leg, and could easily be fitted to add compliance to a rigid leg like what openDog currently has.
@@xaytana absolutely agree, this mechanism would give him the torque he needs on opendog.
@@xaytana i have to say in defense of James Bruton your accusation of arrogance is plain wrong , the phrase '' we are all on the spectrum '' comes to mind and may be applicable , James like a huge number of makers likes to forge his own path but arrogance is not one of them .
Nice work. The walk though in cad was great.
Thank you!
Beautiful! Would like to see it motorized and driven with a controller!
One of the best video I watched in this lockdown situation.
I wish to see some more about this in future...
Really cool mate! I LOVE IT!
How I missed comment from Ivan Miranda itself?!! :)
@Payton Lane It's a scam
@Matias Spencer instaportal has really bad backlash and puts you at a mechanical disadvantage
This guy needs to be seen by more people!
This guy agrees! :)
@@Skyentific I'll share as much as I can! Haha
the cad drawings of line 1 and line 2 were extremely useful to visualize how it works. Thanks for putting those together!
Hi, it is a good design. This is called tendon driven actuator or robot sometimes it is called as cable driven mechanism. One of the best example is davinci surgical robot instrument arms.
daVinci engineer checking in. Aravinth is correct - the robot arms on the daVinici Standard, S, and Si were largely cable-driven. The current Xi system does NOT use cables (though there are some flat metal belts on one axis) in the robot arms. However, nearly all daVinci surgical INSTRUMENTS do still use cables. In fact, the very first CAD Skyentific shows is very similar to the system used in the instrument wrists. link to a video that shows some of how that works: th-cam.com/video/KNHgeykDXFw/w-d-xo.html
@@bschena Yes absolutely right
bschena .... why was cable drive abandoned ?
bschena what is the advantage disadvantage of the cable/flat metal belts that caused the change?
@skyentific mentions this being back-drivable, is there a way to prevent that in this system, if that is unwanted??
Thank you immensely for your input
@@cedricpod They worked very well, but were not terribly stiff and required a lot of periodic maintenance to maintain performance. The fleet in the field started getting so large that having to touch every arm on every system a few times per year was a growing headache for both ISI and the hospitals.
I don't think the spool to large pulley size makes a mechanical advantage because the large pulleys aren't moving, they are just functioning as a smooth corner for the cable. So it is only the spool to small pulley that function as a block and tackle.
Alana Catherine ..... possibly you missed the point of the design .... i am still pondering it
Not at all, look at how the design would compare to a system that would be used to lift something instead of rotate it. The large pulleys are only functioning as bearing to allow smooth rotation around the axis, but they aren't actually part of the "reduction" system. The function of the size of the large pulleys is only to allow the small pulleys to have a straight pull on the cable.
Basically, if you look at the very first drawing he did with trying to lift a weight with only one pulley, that is exactly what the large pulleys are doing. In a block and tackle, it's only the pulleys that "move" that actually create an advantage. The fixed pulleys only redirect the force to make the system take up less space. You could get the same advantage with less pulleys but it would be a much "longer" system. (Hint: compound pulley)
@@randomalleycat Yes, precisely. The big pulleys allow it to maintain a more even pull on the cable when the arm is moving.
@@randomalleycat But the amount of cable in contact with the large pulleys reduces as the joint closes, so I think the small pulleys on the forearm do count as "moving". The opposing cable large pulley arc increases by an equal amount, but since you could exclude the opposing cable and still be able to contract the joint in one direction, I don't think that will cancel the "moving pulley" advantage.
This is very interesting...
I've been looking for an actuator like this for a long time, but hadn't seen one before. I had planned most of the other parts of the system that I wanted to build, but was missing this piece. The basis of the robot I want to build is a central rotating shaft, and a system of clutch units that engage the shaft. These clutch units would be variable, and could either apply a controllable sliding torque, or lock to the shaft to produce a burst of force on the cable.
The main advantage of this is that you only need one massive motor centrally located, and then every limb has access to the full power available from the motor. When not being moved by the motor, the clutch for each joint could lock in place and provide zero power holding torque.
Multiple joints can be actuated at the same time, and pulsing the clutches quickly between engaged and immobile (with a small amount of spring based backlash) could allow relatively precise multi joint simultaneous control.
Awesome job. Since I met you at maker's fair in Paris you amaze me by your simple ways to make great things work smoothly! You definately deserve more attention!
Thank you a lot! I really appreciate this. I really liked Paris Maker Faire. Very friendly place!
Your enthusiasm and amazingly thorough explanations make all of your videos a delight to watch. As much as I don't need another project right now, I feel like I should begin printing parts for my own robotic arm.
Thank you for another amazing installment.
I was looking for something about cable driven mechanisms, but this work expands my thoughts, thank you
Wow, with this design, if it's got the kind of mechanical advantage you calculated, you could use a fairly small stepper motor to lift a massive amount of weight! That's awesome!
it looks really cool, amazing!
the cables in your design they don't overlap when they wind up on the drive shaft, beautiful
Excellent concept, well engineered! Love your videos, please keep them coming!
I love your style of talking simply, which makes me really understand from you while I am still a student in mechanical engineering thanks alot
i love the way he says pulley , just love it hahahah
@@abhishekprasad2935 lol
I'm not even a student. I'm just someone who finds this stuff neat. He explains it so well that it all just seems simple and intuitive. Like, I feel like I could have come up with it and built it based on how simple he makes everything sound.
So cool joint!! Hope you continue uploading new videos like this! Congrats for the channel, so interesting!
That's a really cool mechanism. It really leverages the advantages of 3d printing. Props for designing it yourself. Very impressive.
This is exactly what I've been looking for (even the reduction ratio).
Thank you Skyentifc !
Great idea . Amazing the way you take existing concept and leverage it.
Thank you a lot!
Beautiful, simple , elegant and nicely explained. Keep up the good work.
I like how the axial movement of the rolled cable in the driver shaft could be used to activate toggle switches on each end and keep these very close to a motor without an encoder
Thank you brother I learn something today. This is really good video!
Very well designed ! Thanks a lot for sharing this build !
Nice and smooth!
You could get a much higher reduction ratio with less pulleys in the joint if you use differential pulleys, would need both ends of each cable to be anchored into the winding drum but that's easier than trying to fit more pulleys into the joint.
I think there is a good chance this is one of the lightest joints for the strength that can be achieved!
very clever, and i like your honest style and clear delivery method
Wow, never seen something like this! Cool!
Damn that looks awesome. It runs so smooth as well. Nice job!
Sometimes the simple things work the best, you have nailed it. Thanks
It's crazy how smooth it is.
You did such a great job designing this!
Edit: why not use this technique in the robot arm? pretty sure it's possible to improve your already impressive design to make it thinner and increase the angle.
Joannot this probably introduces a lot of friction due to the increased contact between the cable and the pulleys. Not sure how that will play out in actual applications but I'm assuming it will hinder the torque tracking ability.
Bump this (follow-up) question! Why did you decide not to use this style of mechanism for your ongoing project? Was it because of the friction like @Kenny Kim suggests? Does using a mechanism like this complicate the placement of motors and resulting weight distribution?
i'm super impressed and enamoured by this beautifully smooth design too, but one issue i can imagine are the loads applied to some of the small bearings and axles that hold them, further into the reduction.
@@DMonZ1988 The force is the same at every pulley. The cable tension is the same everywhere, so each small pulley gets 2x the cable tension shear load on the axle.
zero backlash gears are used in the Canadarm and Canadarm2, if that's what you are asking.
Great idea sir ! Thank you for your sincere sharing !
This is amazing. Thanks for sharing!
Your robot joint is awesome!
Thanks for sharing.
I have been wondering about cables for awhile! This is a very cool system, thank you for sharing!
Thank you for your comment! :)
Wow! You are genius!
Very nice. Thank you for sharing! Would be interested to see how this type of reducer would perform under load when powered with a motor.
Very interesting, I really going to try it for some of my projects ! Thanks for your work And researches !!!
Really interesting. Keep up the great work! :)
This is amazing idea! Thanks for sharing
a very well thought out construction! thanks for sharing your findings!
That's absolutely beautiful!
wow, very smart! I liked and subscribed! hope to see more awesome content from you!
Thank you! YOU are the best!
quality content yet again, thanks!
Such an elegant (and quiet) design! Love it!
Very nice Idea. Great work !
BEST video so far! AWEsome concept!
Thank you a lot!
@@Skyentific
You are welcome. But really... that is an AWESOME idea!
By the way... I am the guy who made the MegaMotor6. Google it. Maybe we can do some joint collaboration on something.
Excellent video !! Amazing job !
Sarcos and Raytheon do a joint very similar to this in their exoskeleton system. Very cool to see it more fleshed out! Very well thought out and designed!
Thanks for the great video!
This is a very interesting approach, especially for compliancy since this is so easily back-drivable.
This would be a nice joint for a quadruped.
This is absolutely brilliant!
Just found your channel and I'm hooked!
Absolutely amazing. Super underrated channel!!
this was the first ever video i had seen in your channel subbed to your channel :)
Thank you! :)
Absolutely outstanding interpretation!
Very interesting joint. Thanks for sharing.
That was really really cool!
Never thought to use leverage like that!
Thank you!
11:00 hahhahahaahha !!! xD
oh.. i get it!! its a joke from star lord
That was a Thumb, right?
Wow, thats a fantastic mechanism, very cool.
Thank you very much for sharing your great job. This is very interesting
I love this guy. This was awesome!
Very cool! Nicely done!
And that is why us animals have tendons. Nice work!
Thank you!
Really cool, thank you for sharing this! I learn something from everyone of your videos :P
Very good job!!! This one and others shown in your channel
Great job yet again!
really amazing!! great design!
Hi.
I have been working on a cable driven system for a while now that uses this principle.
I have worked out how to do it without having the cable travel sideways on the drive pulley and also incorporate a high reduction system at the same time say 10:1 but can be configured from 2 to about 30 to 1.
It has no backlash. This allows for a smaller higher speed motor to drive it.
Awesome, can you share any information of documents about this kind of mechanism? I'm a student in major of Mechatronics engineering, and I'm really interested in these kind of knowledge, especially in these days when the situation is damn hard, lol. Anw, take care and keep up the good works.
I want to know more about this kind of joints Please
me too i am interested
Me too
@@laiquocbao2565 Hi.
There's an article about this type of arm here...
www.cs.cmu.edu/~cga/c/0749.pdf
I plan on doing a video on my adaption of this shortly
Very clever... very well built... thanks for sharing. :)
The very end is hilarious!! Nice piece of engineering
Thank you!
thank you very much! your content is amazing.
Great job mate
Great Job
Super cool design!
Actually, I like it by a lot! That's a great one! Thank you!
Great video. The ending was too funny!
Wonderful example... Thanks!
Thank you!
I studied wire driven robots' arms. Using Snatch blocks principe is interesting. I didn't remembered seeing that but yours is quite compact. Well done
supporting comment to encourage this dude to keep on shooting awesome videos :)
I will definitely be using this type mechanism for my canoe loading system on my roof rack.
Cheers mate, thanks for sharing!
Very cool! We use that exact same concept only with much larger hardware, to automate scenery movement in theaters. Wires are redirected from hanging or rolling scenery, (and through double purchase snatch blocks in some cases) and run around both sides of a cable drum and kept in tight tension to enable very fine movement. We're talking pieces that weigh hundreds of pounds being able to fly consistently and safely to within a mm of the mark, night after night.
That really look interesting, great study.
I love this guys channel. Totally wanna use this technique for my life sized Johnny-5 robot one day. If i can ever muster the effort!
Great job, I enjoy your videos.
Really cool system! It’s surprisingly compact.
going to replace the gearboxes on my brushless robot dog design with these. Awesome idea skyentific!
Good idea !!!
Just I impressed your idea! Keep go on improvements.
Awesome work!
Very nice project .. Please keep making such videos
your cad is really good, love seeing it.
After recently studying some of Leonardo da Vinci‘s inventions, I noticed that his automaton used pulleys and it seems that he had the right idea.
i had missed this. nice one
awesome! keep up the good work!!!
Super work
Awesome video. You’re clearly brilliant.