micrortps_client and micrortps_agent UDP connection not working

[evbernardes]

Describe the bug px4_ros_com successfully compiled inside my ROS2 (galactic) workspace, and activated on the PX4 side. I manage to make a connection between by UART over USB, but UDP connection never works and nothing is sent. Tried both with access mode and station mode for the WiFi.

To Reproduce This works:

1. Connect computer to pixracer over USB
2. On PX4 shell: micrortps_client start -t UART -d /dev/ttyACM0 -b 460800
3. On my computer terminal: micrortps_agent -d /dev/ttyACM0 -b 460800
4. Opening rqt I can see the messages being sent

This DOES NOT work:

1. Connect both pixracer and computer with fixed ip adresses to the same network over wifi.
2. On PX4 shell: micrortps_client start -t UDP -i <ip.adress.of.COMPUTER>
3. On my computer terminal: micrortps_agent start -t UDP -i <ip.adress.of.PIXRACER>
4. Opening rqt, nothing is exchanged

Drone (please complete the following information):

• mRobotics Pixracer board with up-to-date PX4 Firmware
• ESP8266 wifi module
• Ubuntu 20.04
• ROS2 Galactic

Additional context As another unexpected behaviour, even though I correctly set the ip adress of the drone, I get the message: 1641562296.353968 [0] micrortps_: using network interface eno1 (udp/ANOTHER.IP.ADRESS) selected arbitrarily from: eno1, wlp111s0, while eno1 is the ethernet interface my computer uses to connect to the internet while wlp111s0 is the wifi interface it should be using. Disconnecting the ethernet and relaunching micrortps_agent removes this message, but still doesn't work.

[benjinne]

I'm not sure how to fix your issue, but is mavlink working with the wifi module? Also, the message about an interface being selected arbitrarily is a standard message when using cyclone DDS. You can try switching to fast DDS and see if that helps.

[evbernardes]

I'm not sure how to fix your issue, but is mavlink working with the wifi module? Also, the message about an interface being selected arbitrarily is a standard message when using cyclone DDS. You can try switching to fast DDS and see if that helps.

Thanks for your reply! Sadly since I didn't have any replies until now and I have a time constraint, I had to give up and install ROS1 Noetic with Mavros.