You've never seen the Robot Joint like this one!

hello and welcome to my channel today I'm going to show you where a unusual reducer that I am this is a cable driven a reducer I have not seen the reducer like this before so I think it's gonna be very interesting for you I designed this reducer around one year ago when I was looking in details to the ambidextrous armed robot arm which called el ims - I made the video about this robot arm last time I am as 2 stands for the low inertia manipulator with the high stiffness and strength and I really liked the reducer the cable driven reducer which they used in the elbow basically in the wrist they also use some kind of the same reducer I was really impressed by this reducer and I wanted to design something similar but different so I came up with this idea I don't think that I am the trust who invented this reducer because the construction is quite simple so I'm pretty sure it existed before so if you know the name of this reducer or if you have any information about this kind of reducer please leave the comment in order to understand how this reducer works you need to understand how the Polish works and for this there is a really good video from smarter every day the video is called why snatch blocks are awesome but basically it's like this for example you have a weight and you need to lift it if you take just one Pony fix it to the ceiling and pull this rope like this you don't have any mechanical advantage but now if you add some more pulleys so in this situation with 2 police you're gonna have mechanical advantage of - and of course you can increase it and for example in this situation with already one two three four parties you're gonna have the mechanical advantage of 4 and so this is a basic idea which I tried to use in this reducer so let's look into the mechanical design in order to better explain you have this reducer works I prepared some CAD drawings so I have several cut files here and so let's start with the simplest one so this is kind of the simplest design so this is the output arm this is the input arm there is only one big poly there is this driver poly so the motor should be connected to this driver pollen and this big poorly it has two V slots this is not important this is just for the construction so one wire goes through the one slot and another wire goes through the another slot and there is this small poly and similar small poly here this is just to redirect their wires let's look at the path of each wire so the wire number one goes like this and you see that it goes through one side of the poly so when this verse is gonna be a roll on top of this driver poly it's gonna pull this arm into this direction the second wire looks like this and it goes through other side of the polis so when the other wire is rolls on top of this driver poly these wires rolls from this driver poly and so like this it allows this arm to goes into this direction when the driver polarity to the opposite direction this arm moves to the opposite direction so this is a very simple design there is no mechanical advantage here so the mechanical advantage is just one but now if we add some more police we can do something like this so here again the output arm the input arm driver police so the motor is connected here and there is these two big police so let's look at wire number one and this wire goes like this it always goes through the same side of big polis and it's basically the same block-and-tackle system but just a roll on this big boy so you see this is the classical block-and-tackle system and the wire number two looks like this so it's actually the second block and tackle system which rolls on this big police from the other side so here you see that this system is already gonna have the mechanical advantage of tune so it's basically like to block and tackle system rolled on this big police like one two now let's see what we can do with the three big bodies in the case of the three big porous the wires goes like this so again this wire number go search through the same site of the big polis and again you see that this is block-and-tackle system with more police and this block-and-tackle system has the mechanical advantage of how many of Surrey and the wire number two is another block and tackle system rolled on this big bodies and now let's see what we can do with the four big bodies and this is for again this is a driver Paul is the input and the output arm and let's look at wires so this wire number one goes here and TDD and on driver poly you see that wire goes again through the same side of the big porous you see again that there is this block-and-tackle system this block-and-tackle system has the mechanical advantage of four and the same block and tackle system is made with the wire number two which you can see here so the wire goes here through this pouring through this one through this one and it goes to the driver problem I used this system with the football saucer with the mechanical advantage of form and I made this design so here I don't draw any wires but I draw all the porous there is police here here on the output arm and there is poly here and here on the input arm and so here I have the mechanical advantage of block and tackle system here and also I have some reduction because the difference of the big pulley diameter and small poly diameter so the driver poly is this one and it has way smaller diameter than this big police actually it has five times smaller diameter so I have the mechanical advantage of 4 and the reduction of 5 between big polar and small pollen and so in total this system gives me the mechanical advantage of 20m let's look at actual design so what we can see here this is an output arm this is yellow input arm this is a driver poly so actually to move this output arm I need to rotate this driver poram like these the cables they fixed here and also they're fixed inside the Paula it's overheads difficult to see but it's over here and what is interesting that this system has a reduction ratio of 20 but it's super easily back drivable and I can back drive it quite fast and the belt still unrolls really perfectly like this so let's look at the cable on top it goes here on this big pole afterwards it goes on this pole goes around on the second big polar here here here around on this big pulley comes back here around this one goes back here and goes to the driver Paula another cable it goes from the driver Polly inside this arm over there and it comes out through this pole here it goes around this small Polly on this one around here on this big polar around here and it goes here inside of this yellow pot and it's fixed here so actually on this side you see the entire block and tackle system and you see how it rolls on top of the big bonus let's look again how it works so when I rotate this pulley goes like this from this side it's quite surprising but cable always rolls perfectly you see even if rotated super quickly the obvious disadvantage that this reducer is quite complicated and it doesn't rotate more than this so basically this is something related more than 135 degrees which is okay for elbow because human elbow also rotates around 135 degrees the great advantage of these reducers that it has zero backlash and this is because we used wires so this is another example of the zero backlash affordable reducer so today we looked at this unusual reducer so this reducer is a cable driven and basically it's based on the block-and-tackle system actually on to block-and-tackle systems this system has a reduction ratio of 20 because there is a mechanical advantage of 4 at the police and there is also the diameter difference between the big pulley and the small driver paly of 5 so 4 by 5 is 20 it works perfectly well I have not seen this kind of system before so if you know the name of this reducer please leave it in the comment so I'm not planning to use this reducer in the robot arm but I think it's possible to make a robot arm with this reducer as usual don't forget to subscribe to my channel apparently according to the statistic 70% of my viewers then not subscribe to my channel because people say judge channel by the number of subscribers so I need a lot of subscribers and this also gonna motivate me also you can support this video by putting the like by putting one or several comments and of course you can support my channel through the PayPal or patreon all the links in the description to this video and by the way this is the name of the people who should put me on patreon and thanks to them I'm able to continue doing this kind of projects I'm able to continue with an affordable human sized robot arm and by the way right now I'm sorry engines apart for this new video thank you a lot you are the best so good luck with your projects and see you next time you

Channel: Skyentific

Views: 137,709

Rating: 4.966291 out of 5

Keywords: robotics, robot, actuator, robot actuator, Best actuator, brushless actuator, brushless, robotics arm, robot arm, robot joint, robotic joint, reducer, gearbox, cable driven, skyentific

Id: utDagouxM5U

Length: 11min 23sec (683 seconds)

Published: Fri Apr 17 2020

Reddit Comments

[u/Alli69]

If you tie his hands he'd go mute

[u/Lev_Astov]

This is extremely clever, but he really structured the video poorly to depict that. He should have started with the demo of the prototype, then discussed the concept and design phases.

It's literally a block and tackle pulley system made into a two direction rotational joint.

[u/truemario]

poley=magic

[u/tonzeejee]

Where do you light it?