Inside a Universal Robots Axis

Disassembly of a lower axis from a Universal Robots Cobot.

[@Bartholinn]

I always wondered the inside of the UR. Thank you for the video.

[@dutch6649]

Nice job man. Really appreciate this.

[@bhavyawadhwa3669]

amazing video thanks for sharing!

[@BeekersSqueakers]

Blew my mind when I realized the pink lubricant was for a strain wave gear.

[@vaselina111]

Why is it surprising? I honestly dont know

[@jamieclarke321]

crazy you can find videos like this on youtube

[@andrewbednar7251]

Thanks for the tear down! Question 1 at minute 3:25 a rotatory sensor is removed. What type of sensor is that? Is that for tracking absolute rotation? is it a torque sensor? Question2 at minute 5:50 there is a Fence on the optical encoder and it has a linear actuator to press down a plunger. What is that for? Does it limit the orientation uncertainy at startup?

[@home_engineered_stupidity]

I am happy you enjoyed the video. About question 1: That ist most likely an encoder to track the position of the output side of the gearbox. Together with the second encoder which tracks the input/motor shaft rotation. It can be used to find the robots position after a restart without having to move the robot into an endstop to home its position. And about question 2: The litle pin is acting as a sort of brake. In its resting position it is blocking the star shaped piece which is connected to the motor shaft. When actiated the pin is pressed down and out of the way so the motor can spin freely. This can be used to prevent the robot from moving when it is turned of which is nessesary because the strain wave gearboxes are backdrivable. It can also be used as an emergency brake. I also want to say that I cant be sure about any of these things because I am not a professional about universal robots.

[@Evgenkr]

A1: one encoder no the shaft, two in the spring suspension, values diff = resistance force - detection endstops and touch, because it's a cobot axis.

[@victorrzhang]

RLS encoder - uses a magnetic ring and hall effect sensors. This encoder is used so that the wires can be fed through the center of the actuator.

[@MrHailong68]

with UR10 this joint is Elbow

[@jcmtzros]

very nice job. pls, let me know if Im on correct way. These motor is a BLDC with a torque sensor , one encoder and an harmonic drive???. obviously with its power electronics based in a DSP and mosfets to boost the motor. thank you.

[@venkatagouthamvutti]

its an awesome video with a great work, i would like to request you to do full robot dessembling video, we will be waiting for it, thank you...

[@myargi]

Thank you. Clear job.

[@En1Gm4A]

So there are two concentric axis in the middle ? one for holding the Rotor - the outer one. And one holdeing the output shaft (probaply for stability reasons of the output) and transmitting the outputshaft rotation to the encoder in the back? You have been able to rotate the rotor after removeing the Outputshaft

[@En1Gm4A]

@7:00 that is all the breaks there is to it? seems a little uderengineered - what do you think ?

[@fatihmeral9863]

I thought the same, but I guess when the weight of the arm is divided by the reducer ratio its enough

[@usamaarshad1792]

Hey thats a great video i was wondering, where was the force/torque sensor?

[@adisharr]

In a CB series robot, there isn't one. Torque is measured by motor current. In the e-series, the sensor is located at the end of the arm.

[@吴碧峰]

Great job. Could you share the parameters of the motor and sensor？ Thanks

[@willl3245]

ahahah, nice try 😂😂😂

[@matthewmeans871]

The flange that they take out near the beginning looks like it couldve been a rotary optical encoder, but there is one clearly later on as well (the see through disk with one dash that feeds through the brown underbelly component of the IC). Anybody able to clarify what the difference is for me between those two components?

[@home_engineered_stupidity]

Yes correct there are two encoders. The one I took out first is connected to the output of the Gearbox and the second one is connected to the input. The one connected to the input keeps track of the motor Position. The one connected to the output should be an absolute type encoder. I guess this enables the robot to know the position of the axis right after startup and eliminates the need for homing the robot.

[@dcode4720]

Great job. Could you share the information of the encoders? Manufacturer or model. Both joint's side and motor's side, Thanks!

[@jonashdjg1345]

Pretty shure they use U.S Digital optical encoder on the motor side, can't exactly tell what the output side is. But definitly hast to ba a magnetic one, maybe something like a RLS AksIM-2.

[@hoarp001]

@@jonashdjg1345 Do you mean that the lower optical encoder is on the motor rotor and the shaft encoder which is removed first in the video is a second encoder that is connected to the motor output via a shaft in the centre? I was wondering what that was. I am currently designing something with an RLS AksIM-2 and they supply the read head and the codewheel separately, whereas the unit seen here looks like an all in one type encoder product. It also looks like it senses in the radial direction around the outside of the shaft rather than reading a codewheel in the axial direction. Mysterious. either way, fascinating video.

[@jonashdjg1345]

@@hoarp001Its also possible that they use one frome a different manufacturer but for me it looks like they have just designed a case and a small shaft for the Aksim. But the Blue pcb irritates me, maybe it could also just be a completly costum encoder they build. They use a incremental encoder on the Motor and an absolute on the output shaft (after harmonic drive). Im pretty shure that they do that for one the absolute Encoder only rotates 360° and directly measures output shaft angle and second, with two encoderes they can quickly discover torque spikes for their collision detection with humans.

[@haraldthomas6757]

US Digital EM1, Hubdisk is customized

[@jonashdjg1345]

Is it really a EM1 and not EM2? How can you tell?

[@hoarp001]

If the encoder is optical by way of that glass disk and the pcb mounted read head, then what is the first item you removed that has the freely rotating centre? I assumed at first that was the encoder. Unless it has two?

[@victorrzhang]

I think you are right, there are two encoders. The first one is the RLS encoder - magnetic, and then they also have a US Digital optical one.

[@MrHailong68]

EM1 Transmissive Optical Encoder Module, the first encoder

[@lequang1261]

hello, can the hamonic drive be easy to backdrive ?

[@ENGEL333]

Depend of reduction ratio. Less ratio - more easy to backdrive.

[@RiteshSuthar-rx3qu]

is this UR3 or UR5?

[@fatihmeral9863]

what type of motor is that?

[@henria.277]

Brushless DC + Force sensor + relative encoder with a harmonic/strain wave gearbox at the output

[@АлександрЯмщиков-т9с]

Can you make a high resolution photos of the board? Thanks!

[@willl3245]

ahaha, another nice try😂

[@ENGEL333]

Watched video several times, but i dont see torque sensor, which must be in cobot. Anyone found it?

[@henria.277]

It's the wavy metallic part removed first on top of the PCB that is bolted onto the shaft

[@JM_Tushe]

Ah~ it's a beauty. 🥰 I think I leaked a little.

[@bambumbambu]

can you make a better resolution picture of pcb please?

[@Schneekanone_TR8_gaming]

Du hast die falsche Zeile benutzt du musst die spring Ring sanierte nutzen die nach außen zu öffnen geht

[@williamhuang5329]

Hanzhen harmonic drive gear , strain wave gear , robot joint , over 30 years experience .