BLDC Control ODrive-for-ARC

Hi Mickey, nice tutorial! In the ino file, you are only sending the position received by ARC to the ODRIVE, and no positional feedback or speed to ARC am i right?

Yes, it is just the basic setup... It allows you to use your BLDC motor just the way you would use any other servo in ARC! But there is a lot more that can be done...check this code, to get started!

https://github.com/odriverobotics/ODrive/blob/devel/Arduino/ODriveArduino/examples/ODriveArduinoTest/ODriveArduinoTest.ino

Hey guys...a little bit of salt here, I recently updated the firmware of my ODrive, and the Arduino code is no longer working for me! So if you are still on v0.4.12 you can go ahead and use it, if you are updating, it will break your motor settings and the code! :)

But I took some time to revisit my settings and tuned the BLDCs again, so everything is working just fine, if there is anyone using the script and wanting to update, hit me up!

I also chopped together a quick script that lets you control your BLDCs with a PS4 controller in Python, to test a setup and put it to Github... https://github.com/SwannSchilling/ODrive-for-ARC/blob/main/ODrive_PS4.py

Good info! So your fix was just going back over and redoing all your settings..and it started working again?

The company Flipsky (which I've used for my hoverboard project) has created a clone of the ODrive. Its slightly cheaper at $92, so a little less than $50 a channel. Might order one to compare with the ODrive...

Flipsky ODrive clone

@Fxrtst: Is the same company ? They don't sell hoverboards maybe I'm missing something.

Yes, sorry, they manufacture ESCs for electric skateboards. I used one of their ESCs (velocity control only) for my hoverboard project. They are now making and selling a clone of the ODrive because its open-source (velocity and position). You use the ODrive software for their clone, and I used VESC Open Source Project for their ESCs.

Ha ok makes sense. They are "experts" in cloning, the original vesc: https://vesc-project.com/Hardware

btw ODrive since 3.5 is not open hardware anymore, only the firmware is open source: https://discourse.odriverobotics.com/t/3-5-odrive-schematic-release/1246

So the hardware is not an "official" ODrive 3.6 clone, maybe they studied and cloned the design, but, they shouldn't advertise the compatibility... maybe is nothing wrong.

What makes the difference is the firmware, community and support so unless they (Flipsky) spends the time and resources to build their firmware, I would pick the original product.

@Fxrtst: Does VESC supports position control with encoders ?

@Mickey666Maus, So you are testing FOC, position control and gear design what is after that ? What you plan to build or what you think can be useful for ?

Quote:

Does VESC supports position control with encoders ?

Edit: Looks like it does! And always has. From the developer:

That Flipsky board looks really bad its got zero pins to use encoders and I doubt it will be suitable for what we are doing...which is robotics! Also what @ptp pointed out is a fairly valid point....

Quote:

So the hardware is not an "official" ODrive 3.6 clone, maybe they studied and cloned the design, but, they shouldn't advertise the compatibility... maybe is nothing wrong.

What makes the difference is the firmware, community and support so unless they (Flipsky) spends the time and resources to build their firmware, I would pick the original product.

My SimpleFOC Shields also arrived...lets see what they can bring to the table!

@ptp I am planning to design a bigger robotic arm and also a hip joint for ZOE, which will offer more torque and a more degrees of freedom... I am about to do an assembly video of the gearbox and will make all those files available, if you are interested in building one for yourself! :)

I dont want to clog up this thread with more info..head back to robot dog thread...your gonna want to see this!

You can always clog my threads with god findings...happy that you do!

Here that assembly video one more time...I will upload all those files asap, if you guys want to give it a try!!! :)

This is very very good and also understandable video of PID control, if you are setting up your ODrive the

.controller.config.pos_gain = 20.0 [(turn/s) / turn] .controller.config.vel_gain = 0.16 [Nm/(turn/s)] .controller.config.vel_integrator_gain = 0.32 [Nm/((turn/s) * s)]

are the values that you would want to tweak, when setting up your motor...the above video explains what they mean, and how they are used.

...That was a good video. I found Skyentifics description a bit better to understand in reference to position control...I also believe James B has a good explanation for how we are using it. In the case of MJBots dev kit...I find that playing with the "P" (proportional) of PID, affects the stiffness or compliance (springiness) of the motor on full stop or holding. And "D" (derivative) of PID, as dampening that motion. And James says stay away from "I" (integral) unless necessary.

That is funny, I think I watched most of Skyentifics videos, but cannot remember that one...post it if you can find it! Good you are having the MJBots dev kit, I will definetely also get one, to see the differences!

James B has so much stuff out there that I might have missed a few, but his and Skyentifics are really awesome channels...

Sure it starts...@ 7:30... This is the MJ Dev Kit.

Ah, coooool this one is the newest...I did not check into it because I don't have the kit, but I will just watch it now to be up to date! :)

FYI to all, don't forget the Chinese New Year is coming up...be sure to order all your testing stuff before then or you'll be waiting a long time for it.

Ups...good idea!! :D

All files for printing the gearbox are uploaded, in case anyone is interested...

https://www.prusaprinters.org/prints/53681-cycloidal-drive-3d-printed-gearbox-401

Hi Mickey, Did you ever make a video of the gearbox in action? I am curious what the vibrations are like at higher speeds.

In the firmware for the set servo position, don’t you want to map 180 not 100? Because ARC will by default send 180 servo position degrees

odrive.SetPosition(0, map(pos, 0, 100, 0, 180000));

Should be...

odrive.SetPosition(0, map(pos, 1, 180, 0, 180000));

also, that code will only move one osdrive and no pwm servos. If you simply add an IF condition to make d0 the o drive, the rest could still be pwm servos.

@Perry_S this is a clip of the gearbox being controlled with ARC! I will make a torque, speed and precision test soon... :)

@DJSures thanks a lot for looking at my code, I might have just typed those numbers wrong, this was more or less just a proof of concept and meant to be developed further...at that time nobody seemed to be interested so I kind of forgot about it! But since the firmware update of the Drive, the whole code would need to be updated anyways...

So I guess if there are a bunch of people being interested, we could think about doing so?

I think at the moment there are a few options for BLDC control being discussed here in the forum...

Can you adjust the velocity, set positions etc in ARC in your video example? What changed in the Firmware update?

Hey, this should be possible...all you would need to do is to adjust the Arduino code! I think @DJSures would take a look in case there are a few requests?

These are the changes https://docs.odriverobotics.com/migration

But you might want to go ahead and setup your motors once again so everything runs as smooth as possible... I revisited my settings too and started from scratch! :)

Oh also I found that GUI now, that a nice thing to have... Thanks for pointing it out to me, I guess they are not advertising it too much since it is still in beta!

I might have to print a test rig at some point...and just found a bunch of useful ones, I case anyone needs something that is ready to go!

https://discourse.odriverobotics.com/t/useful-cad-resources/257/14

Yah we can whip up a firmware once you're ready. And a robot skill that allows fine tuning the specs & details of the servo.

Exactly...no rush, it only makes sense once there is a real usecase scenario! :)