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
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?
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)
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.
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.
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?
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.
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?
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.
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.
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?
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?
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?
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.
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
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.
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: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-1OsV87dCegs.html
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
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.
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!
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.
@@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 :)
