ROS2 PX4 Colcon build notes/ideas

[dagar]

PX4-Autopilot fully building in colcon (optionally)

• use msgs/ directly instead of px4_msgs (decide both datatype naming and topic mapping)
• in tree Nodes
  • Node that wraps micro XRCE DDS agent
  • Node that translates existing PX4 topics to ROS2 standard (odometry, sensors, etc)
  • could be a good place to handle logging, parameters bidirectionally
  • Node that "manages" existing PX4
  • full SITL use case
  • builds and deploys embedded PX4 (eg px4_fmu-v5x)
  • Node with OFFBOARD example as a starting point (pull in Jae's stuff)
• launch files for a few common scenarios
  • basic SITL + gazebo (+xrce agent)
  • real vehicle deployment (Linux + NuttX)

[bradenwagstaff]

I took Jae's stuff and expanded on it a little bit. The main change I made is you can launch a simulation without QGC, fly that quad using keyboard teleop controls to control velocity setpoints instead of position setpoints. It also all runs under one launch file and runs a node that manages MicroDDS and PX4

I'm currently making an in depth tutorial targeted at new ROS2/PX4 users to help them get this example running and will film a tutorial walk through within the next week. A lot of this is motivated from the recent ROS call and the expressed need for tutorials that help people get started

https://github.com/ARK-Electronics/ws_ROS2_PX4_Simulation

Current example is setup as a new workspace, but I'm currently retrofitting it to be a package you can pull into any workspace

[beniaminopozzan]

A few thoughts about having ROS 2 nodes in tree and building them with colcon

• We should have different packages in tree:

  • Core package: the current PX4-firmware

    Node that "manages" existing PX4 full SITL use case builds and deploys embedded PX4 (eg px4_fmu-v5x)

  in @dagar initial post

  • Communication packages: node wrapping micro XRCE DDS agent, ROS msgs / PX4 msgs conversions

    Node that wraps micro XRCE DDS agent Node that translates existing PX4 topics to ROS2 standard (odometry, sensors, etc) could be a good place to handle logging, parameters bidirectionally

  in the initial post.

  • Examples / tutorial package
  • Simulation package (maybe)

  in this way we can keep everything well organized without splitting everything in different repos. Long term goal, having the possibility to do sudo apt install ros-"some version"-px4 would be pretty nice.

• Different packages must be placed in different folders and cannot be nested. I don't know if this can be accomplished without changing completely the PX4 tree like

  PX4-Autopilot
  ├── PX4-core                   # the current PX4-Autopilot
  ├── PX4-coms                 # communication package
  ├── PX4-tutorials             # tutorial package

FYI: At the moment we have the ros2 target, and if we place PX4-Autopilot in a colcon workspace, colcon build will compile a package called px4 containing the PX4 msgs (a copy of the px4_msgs package but with different name). Well, this is true if you are using ROS Foxy but the compilation is broken in Humble (see #21128) the issue seems to arise from calling add_subdirectory in the CMakeLists.txt file.

Slightly off-topic: this action https://github.com/ros-tooling/action-ros-ci may be useful to test future ROS 2 nodes (see https://github.com/PX4/px4_msgs/pull/26)

[Jaeyoung-Lim]

Different packages must be placed in different folders and cannot be nested. I don't know if this can be accomplished without changing completely the PX4 tree like

@beniaminopozzan Probably we can try to make each of the px4 module a colcon package? we can then have a small meta package that runs the rcs

[DronecodeBot]

This issue has been mentioned on Discussion Forum for PX4, Pixhawk, QGroundControl, MAVSDK, MAVLink. There might be relevant details there:

https://discuss.px4.io/t/px4-community-q-a-july-05-2023/32963/1