Wiring with just Arduino, Odrive and RadioLink S.B/PPM protocol

[Nowayoreal]

Hi,
I like this project and I want to build a mobile equivalent. I have odrive controller 56v v3.5, Arduino mega and radiolink receiver with just one signal port i.e s.b/ppm. I would really appreciate your assistance to interface the Arduino with the hoverboard and communicate via the radiolink. I am super new to odrive. Any sample communication code and wiring would be highly appreciated.
Thanks in advance!

[LuSeKa]

Can you specify which receiver exactly you are using? I might be able to add support for it shortly.

Everything else (e.g. comms between Arduino and ODrive) should just work.

[Nowayoreal]

Attached is the receiver and transmitter that I plan to use.

[LuSeKa]

Nice. PPM should be relatively straight forward to decode and almost certainly easier than SBus. I'll try out this library when I get a chance, but you might want to take a look yourself and see if it just works out of the box https://github.com/Nikkilae/PPM-reader

[LuSeKa]

Hi @Nowayoreal, I added support for PPM receivers on this branch. I don't have the hardware to test it, so it would be great if you could try it out and let me know how it goes. Let me know if you have any questions.

[Nowayoreal]

Awesome! I'll test it tomorrow and let you know. Thanks so much

…

On Sun, 5 Dec 2021, 06:40 Lukas Kaul, ***@***.***> wrote: Hi @Nowayoreal <https://github.com/Nowayoreal>, I added support for PPM receivers on this branch <https://github.com/LuSeKa/HoverBot/tree/ppm_receiver_support>. I don't have the hardware to test it, so it would be great if you could try it out and let me know how it goes. Let me know if you have any questions. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#5 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AWYYWULG3Y6XRDB5ZDKCOY3UPL3L7ANCNFSM5JLJZU3Q> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>.

[LuSeKa]

Hey @Nowayoreal , have you had a chance to try out the PPM interface?

[Nowayoreal]

Hey!
Thank you very much for your kind message. I am sorry for not have replied in time. I got a PWM receiver instead which I tested and it worked fine as I could visualise the response from the Arduino serial plotter. However, when I tested it with the Odrive controller connected, it did not work, but I think the problem was from my hoverboard wheels or my connections. I did not use IMU, so I connected my Arduino TX and RX directly to GPIO 1 and 2 of the Odrive. So, synchronising it with Odrive controller and putting the motor in closed loop control is exactly where I am hooked up at the moment.

[Nowayoreal]

Hi @LuSeKa
I have been able to resolve the RC problem. However, when I tried to test the motors with the "odrive_test.ino" code, the wheels will spin a little bit and stop when I press the throttle knob. I am wondering if you could help me to troubleshoot it?
Thanks for your time

[LuSeKa]

@Nowayoreal that sounds a bit like it could be a problem with the ODrive setup rather than with the Hoverbot code. Did you successfully run the ODrive setup scripts? A good debugging step would be to run the motors right from the ODrive Tool (in current and position control mode) to verify that his works fine.

[Nowayoreal]

@LuSeKa Thanks for your reply.
The setup script runs fine although, at first, it returned errors when executing the save function. However, I solved it this way
try:
odrv0.save_configuration()
odrv0.reboot()
except fibre.libfibre.ObjectLostError:
..........

I tried both the position and torque control mode from the ODrivetool, it returned no error, however, the axes do not go into AXIS_STATE_CLOSED_LOOP_CONTROL when requested, and hence the motors don't spin.

I got this error when I tried the current mode. Although, from here, it stated that the controller has been updated to use torque instead of current. So I used the torque mode instead of the current mode

I tested both 47nF capacitors with the halls and 23.5nF (two 47nF in series connections since I don't have 22nF recommended). Both worked fine with no error.
I am wondering what I am getting wrong?

[Nowayoreal]

@LuSeKa I was able to get the motors run in a closed-loop state. Thank you so much for your kind help.
When I tried the "odrive_test.ino" code, the motors were quite fast while the throttle is engaged. I am wondering which parameter to change to reduce the speed since it is in the current control mode? I reduced the vel_limit to 10 but it does not change the speed.
Thanks for your time and in anticipation of your response.

[LuSeKa]

@Nowayoreal it's normal for the motors to spin quite fast in current control mode when the wheels are free spinning, even if only small currents are commanded. Even a little torque can make them spin quite fast, since there is not much counter-torque in this scenario.

[Nowayoreal]

@LuSeKa/HoverBot ***@***.***> Thanks for the feedback! I will try the velocity control mode. Hopefully, it will it will get the wheels to spin at the desired speed.

…

On Tue, 4 Jan 2022, 04:19 Lukas Kaul, ***@***.***> wrote: @Nowayoreal <https://github.com/Nowayoreal> it's normal for the motors to spin quite fast in current control mode when the wheels are free spinning, even if only small currents are commanded. Even a little torque can make them spin quite fast, since there is not much counter-torque in this scenario. — Reply to this email directly, view it on GitHub <#5 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AWYYWUK4CYXROZLDMPOEAVLUUJRLNANCNFSM5JLJZU3Q> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you were mentioned.Message ID: ***@***.***>