Can I control PWM signals to esc directly via Mavlink?

MAVLink
1

So I’ve set up a test bench, that includes a load cell that I’m using to measure thrust from a quadcopter. I’ve been able to control PWM signals via the actuator panel within QGroundcontrol, by setting the aux1-4 to Constant Min and manually adjusting the Min value. Information can be found here. This works, but its not ideal and I was hoping I could set these values directly in software.

I’m familiar with QGroundControl, but I have never used Mavlink before. So I’m not sure if this is possible or where I would start looking. I did start looking at the pymavlink documentation and I don’t see anything about constant min/max

I would want to use Pymavlink to accomplish this.

The goal is to be able to read the thrust from the load sensor, and adjust the PWM so that I can maintain a consistent thrust value without any additional stablization from the flight controller.

2

I’m assuming you’re using PX4 (and not ArduPilot, otherwise ask in discuss.ardupilot.org).

You should be able to use the command MAV_CMD_DO_SET_ACTUATOR, e.g. in pymavlink.

Or in MAVSDK-Python it would be:
http://mavsdk-python-docs.s3-website.eu-central-1.amazonaws.com/plugins/action.html#mavsdk.action.Action.set_actuator

1 Like
3

Yes, correct, I am using PX4.

Thank you, I will dig into your recommendation!

4

hello, I also want to directly control the pwm signal and now i am using the pymavlink,
I am able to send command to arm and disarm the vehicle,
but when i want to use MAV_CMD_DO_SET_ACTUATOR it throws an error
AttributeError: module ‘pymavlink.dialects.v10.ardupilotmega’ has no attribute ‘MAV_CMD_DO_SET_ACTUATOR’
I check the file in the site_packages/pymavlink/dialects/common.xml ，there is not the CMD_VALUE, did i do it wrong?

5

Have you updated pymavlink?

6

Hi, I have also run into this with pymavlink: AttributeError: module ‘pymavlink.dialects.v10.ardupilotmega’ has no attribute ‘MAV_CMD_DO_SET_ACTUATOR’ have you found a solution?

Does anyone know if you can change dialects to pixihawk/px4 in pymavlink?

7

Use dialect common.

8

Hi, the common dialect also did not work, but I was able to find a solution by passing it the integer 187 directly.