Great and Affordable Robotic Actuator (MyActuator RMD X8 and RMD X8 Pro)

UPDATE: it works great with Arduino, if we set the “position plan max acc” = 0 and “position plan max dec” = 0. In this case the motion is smooth (no steps).
I have tested the new QDD actuators from MyActuator company (RMD X8 and RMD X8 pro). Each of them has two encoders (one on motor shaft, another one on output shaft), for quite affordable price. Overall it works great, and it even capable to produce triple nominal torque for short period of time.
MyActuator official Aliexpress store is: www.aliexpress.com/store/1101...
MyActuator contact:
Arics Tang: [e-mail]
Special thanks to my special supporter: Benjamin Bacon and Ali Almarzouqi.
Please subscribe. This will help me to develop other projects like this, to bring the bright future closer!
One time donation:
www.paypal.me/Skyentific
If you want to help this channel, please support me on Patreon:
/ skyentific
Instagram: / skyentificinsta
Facebook: / skyentificface
Twitter: / skyentifictweet
#robotics #actuator #test

[@KhalilEstell]

I've been using these motors for my robotics team. They are fantastic. Expensive, but absolutely great!

[@deldrise9169]

I just bought one of these this week. Perfect timing.

[@Skyentific]

Nice! :)))

[@marcfruchtman9473]

Thank you for the review...

[@Skyentific]

I hope it is helpful!

[@Tobbera]

Thank you for your video. I have a X8 myself and while it works really good for basic servo movements I struggle to get my head around how it actually works. How to tune the PID values for example. And how to use the different modes/messages thats availble though the CAN bus. For instance I havent been able to figure out how to do a torque limited position movement, making it act like a "spring". According to the company this is not possible but I refuse to belive that.

[@jimmy0tran]

Nice video! How are they compared to the MIT Cheetah motors?

[@svenuitendaal1368]

Great video! I think that these motors, including their gear boxes, encoders and drivers are indeed affordable. Is it also possible to do torque control on these motors, besides position and velocity control?

[@serafinbachman4583]

Thank you for the presentation. There is any chance that you can show us how to tune PID controllers on real project? Best Regards!

[@douglasburnum9722]

Catching up on a lot of your videos that are super interesting. We are planning on using an Nvidia Orin for a project soon and look forward to more videos with you on it. I am curious what software you use for designing your own actuators with? Do you use Solidworks? Keep up the awesome work!

[@brianlerner9366]

Curious how you connected the actuator to the Nvidia Orin

[@codertao]

You mention one of the advantages of an output encoder is the ability to compensate for backlash, was the backlash testing done with motor powered / maintaining a specific shaft angle? The literature (for a different motor?) says it has a 16 bit encoder, so it theoretically can measure shaft angle down to ~1/3 arc-min. (it also mentions 14 bit in the same document, which'd be a bit over 1 arc-min... but I'm also wondering if it's a magnetic encoder, which might have it's own noise issues) (and testing 'compensated backlash' might be complicated)

[@saeed6811]

I want to make training robotic legs for my son who is disabled. I will buy these if they have sufficient torque. They look nice for the application

[@ivartaim1448]

Were the backlash measurements done while the motor was on or off? Theoretically the second encoder on the output shaft should minimise the backlash to 1-2 encoder counts.

[@aashifrazeen2218]

Can anyone share the code along with the libraries

[@ianseelen1443]

I plan on using these motors for a robotic arm. However I will attach them to a larger gearbox, so one rotation of the robot arm will be a lot of rotations of the motor. Can the motor remember the multi-turn value of the encoder after power loss? Or does it only remember 0 - 360 degrees?

[@Pronobozo]

Is this rebranded GYEMS motors?

[@ishbhatnagar1990]

@Skyentific Where did you get this torque tester from ?

[@statorworksrobotics9838]

Another great video. These are like fine jewels but sadly not very practical because of the price. Another issue is that quasi direct drives are very inefficient when it comes to power. The good thing is that they have decent speed so you could add a couple of external gears to get 5 to 10 times higher torque and potentially further reduce backlash, while still remaining back-driveable.

[@Skyentific]

Thank you. This is true, that they have relatively low torque, but this allow them to have the force feedback. This is why there are a lot of robot dogs with them. But there is no many robot dogs with harmonic drive.

[@christophegroulx7816]

How would it remain backdrivable if you're gearing it to a combined ratio of 50+?

[@coryseaward975]

What motors would recommend for a big robot arm to cnc plaster. Say a 6ft arm

[@martins6376]

Hi, nice video. Can you please send me a link where you bought the CAN bus shield? Thank you in advance.

[@yeokc8757]

Have you ever faced an L2 error: Encoder Calibration Error? It happened after we turned the motor when it was turned off We can't seem to reset the error despite our best efforts Do you have any ideas?

[@BrunswickGauss]

Excellent information and your projects are great, inspired by your projects, I bought a RMD X8 Pro Actuator but I have not been able to make it work with the configurator, I believe it is because of the version of the CP210 drivers, could you tell me where you downloaded the software from? I am using windows 11

[@IvchenkovAndrey]

Good afternoon. 3:23 Do not tell me what kind of connector is needed to connect the UART? Can't determine...

[@Tobbera]

Regarding you step-problems "UPDATE: it works great with Arduino, if we set the “position plan max acc” = 0 and “position plan max dec” = 0. In this case the motion is smooth (no steps)." I dont think this is the best way to mitigate the problem you had. I could see that you had a few "delay" in your code though, maybe they are the ones causing the jerkiness? I have a X8 actuator running over CAN and it moves smooth without altering the acceleration settings.

[@aashifrazeen2218]

I’m trying to control x10 over CAN with Arduino, but it’s not working, it’s using the V3 driver any suggestions what to look for

[@1stzard]

@@aashifrazeen2218 is it CAN bus?

[@trinityklinkert9021]

Hi Tobbera, seems like you managed to get these motors running via Arduino. If you don't mind me asking, which CAN library is Skyentific using in this video?

[@1stzard]

for zero backlash gears, they should use a harmonic drive (worm gear)

[@gerokatseros]

worm gear is different from harmonic drive, i suppose you ment wave gear :)

[@Huddy52]

cool

[@antonioaguilar6467]

Where can I get the software? I can´t find it anywhere

[@Huddy52]

do you think consumer or diy actuators have the accuracy required to run a cnc job or fdm 3d print from a 6 dof arm

[@graealex]

Even industrial articulated arms will have trouble functioning as an FDM printer. Every joint introduces more imprecision. That's why you can get a decent bed slinger for 250 bucks, but would probably need to spend 25k on a 6-DoF.

[@josedavidbravoa]

I bought some of those motors but I don't have CAN or RS485 modules handly, do you know if I can drive those motors using the provided UART module using serial communication?

[@gevb5495]

Great video! Which torque brake did you use? @skyentific

[@matthewmeans871]

What about wiring? I find it difficult to source larger through shaft motors

[@Ender_Wiggin]

You have to give us details on that DYNO or torque machine?

[@Skyentific]

Yes. It is quite simple. The main part is the electromagnetic powder brake, with maximum braking power around 50Nm. And to measure the torque I use a digital torque wrench adapter. I think I first introduced it here: kzbin.info/www/bejne/Z4DWh2ttmaiYndU

[@bolovnyakin7466]

Идеальный английский для тех кто его знает, но не понимает носителей. Спасибо

[@Dave-nz5jf]

Hey . .where can I get more info about how to control this using python . can I use canio ?

[@TheNamelessOne12357]

If this actuator cannot follow constantly changing position it's very bad for robotic arm. It needs to be fixed in firmware. And what exactly is "quazy"-direct drive?

[@MaxMustermann-sm4qu]

Any info on estimated price? (I'm asking, because right now, there are no products listed in their AliExpress-shop.)

[@Skyentific]

Yes, of course, it is 380 for X8 and 399 for X8 Pro: www.myactuator.com/product-page/rmd-x8

[@MaxMustermann-sm4qu]

@@Skyentific Thanks for your reply and the link. 🙏😊

[@BerTav]

Just got my X6 and I am terribly disappointed. Besides experiencing the same behaviour as you with the choppy change of position (tried your suggestion of setting the plan max to 0 but does not make it better), my actuator goes crazy out of nowhere and starts spinning at constant speed infinitely disregarding all my commands. Very risky, would not trust this in any robot of mine. Even trying the simplest sin wave makes it go crazy after around 1sec. The speed it reports is good and accurate even though it is spinning the position measurement is constant or starts jumping around.

[@BerTav]

If this happens to you as well then Skype the company and show them what is happening and they should give you an updated firmware that fixes it. Then after that the fix here of making the acceleration and deceleration 0 works to make it less choppy

[@zyxwvutsrqponmlkh]

So you have the robot cats and dogs covered, what about the robot anteaters?

[@Skyentific]

This would be so cool!!! :)

[@pudelfan3059]

Almost $400? Affordable? I am sorry, but our definitions of accordable seem to differ somewhat. A bot with four legs needs 12 Motors; and that comes out to more than $4500. The tinkerers that i know cant spend that kind of Money on just one project. But still, a nice piece of kit. Peace, Pudelfan

[@Skyentific]

Compared to other companies, this is affordable.

[@peytonmac1131]

Yeah, I had thought that too. Maybe if you only wanted one or two servos, but any more than that and it's cheaper to buy a 3d printer and make something yourself. I can't imagine many hobbyists with that much cash just for one robot.

[@rodstartube]

1:07 "i can feel a tiny backlash..." me: "ok, discarded"

[@Skyentific]

If you want such actuator without backlash be prepared to pay at least 1.5k :)

[@theon2k]

Interesting Ali shop. 2yrs, 2260 followers and only one product with 2 orders...

[@Skyentific]

This is just not true. For some products it is only 1 order. But for such QDD actuators it is 5 to 20 orders. And this is for the new version. I suppose they have a lot of orders for the old version. But now they replaced them with the new version, so there is no many orders yet.

[@theon2k]

@@Skyentific This is easy to check. Click on the link from the description, Products -> view all products. And we see all one product.

[@christophegroulx7816]

@@theon2k i think you got the wrong shop, those guys have sold quite a lot of actuators and also have their own website

[@theon2k]

@@christophegroulx7816 you're right, in the Feedback section I see 25 reviews and can get to the other items as well but from the Products menu it shows me only RMD-L-7015. Strange. I hope our small discussion will help the video promotion :)

[@Mr_nuke99]

First to view !! :)