How to start the micrortps_client on a pixhawk4?

ROS / MAVROS / MicroDDS
1

I already ran a microRTPS agent and client with SITL and it worked flawlessly.
But now I want to try it with the real hardware i.e. a pixhawk4.

I ran make px4_fmu-v5_rtps upload and then try to run micrortps_client start in the nsh but as soon as I press enter I get this hardfault.

The section in the documentation about how to set this up with real hardware is currently wip but maybe someone here already did it.

I saw the other post on this forum and followed it but I still get the hardfault.

2

I found an issue about this.

A workaround is to disable this parameter CONFIG_MODULES_MICRODDS_CLIENT=n
or switch to the last stable version, at the time of writing this reply it is v1.13.0.

3

Hi @florian.pix, I am also unable to start the micrortps_client per my previous post.

After accessing the pixhawk’s nsh> through mavlink_shell.py from my companion computer, I get the following error when trying to start the micrortps_client:

nsh> micrortps_client status
INFO  [micrortps_client] Not running
nsh> micrortps_client start -t UART
INFO  [micrortps_client] UART transport: device: /dev/ttyACM0; baudradevice reports readiness to read but returned no data (device disconnected or multiple access on port?)

This error is originating from .local/lib/python3.8/site-packages/serial/serialposix.py

This error occurs every time I try to start the micrortps_client - whether through the mavlink shell or QGC console. The Pixhawk disconnects from QGC and plays the error tune. The connection between the Pixhawk 4 and the companion computer (a Raspberry Pi running Ubuntu 20.04) is a usb cable into the side port.

I just saw your posted solution; not sure if it applies here but I will try that and report back.

4

If you aren’t using the stable version it might be that mavlink (QGC also uses mavlink) interferes with the microRTPS. You can check this by using the FMU debug port with a FTDI cable and using the nsh shell directly instead. But in general I would suggest using v1.13.0.

1 Like
5

I can confirm this worked for me. Thanks very much for the help!