Communication layer between PX4 and ROS 2. Based on the px4_ros_com project.
This package offers a communication layer between the PX4 firmware and its uORB middleware, and a ROS 2 network, by (de)serializing data over a FastDDS network. It is essentially a reimplementation of the px4_ros_com project, aimed at fully supporting ROS 2 Humble Hawksbill and version 1.13.3 of the PX4 firmware offering a more modular and flexible design, and a more robust and reliable implementation.
The package builds the micrortps_agent node and the micrortps_agent_app executable. It also offers configuration and launch files.
First, you must configure the Bridge topics in the PX4 firmware codebase. At the end of the procedure, you should have generated your version of the urtps_bridge_topics.yaml file. This repository offers a default one with a basic set of topics enabled.
This package can be built using colcon. Find the dependencies listed in the package.xml file.
Then, you can either launch the node or the executable.
A set of parameters is offered for the micrortps_agent node, see the params.yaml file for details.
Currently, this module is kept aligned with our fork of the PX4-Autopilot project. The list of uORB topics that are (de)serialized by default follows. Additionally, some debug and alias topics have been left active for compatibility with PX4. Communication directions are expressed in a PX4-centric logic.
These messages are necessary to perform any flight operation.
| Topic Name | IN/OUT | Description |
|---|---|---|
| battery_status | out | Battery status information |
| offboard_control_mode | in | Used to switch to OFFBOARD mode |
| takeoff_status | out | Drone airborne status changes |
| timesync | both | Clock synchronization |
| timesync_status | out | Clock synchronization status |
| trajectory_setpoint | in | (X, Y, Z, yaw) setpoints |
| vehicle_attitude | out | Current attitude quaternion to local NED frame from EKF2 |
| vehicle_command | in | Flight operations commands |
| vehicle_command_ack | out | Command feedbacks |
| vehicle_local_position | out | Current position in local NED frame from EKF2 |
| vehicle_visual_odometry | in | Pose samples from external VIO system |
These messages are not required to fly but may be useful for debugging and testing.
| Topic Name | IN/OUT | Description |
|---|---|---|
| estimator_status_flags | out | EKF2 internal status information |
| log_message | out | PX4 internal log messages |
| sensor_combined | out | Real-time samples from all IMU sensors |
| vehicle_odometry | out | VIO data parsing results |
These messages are published directly by a ROS 2 node managed by the Agent application. Their data comes from messages sent by PX4 and usually holds additional information (e.g., a ROS 2 std_msgs/Header with a timestamp).
| Topic Name | IN/OUT | Description |
|---|---|---|
| vehicle_attitude_stamped | out | Current attitude quaternion to local frame from EKF2 with ROS 2 timestamp |
| vehicle_local_position_stamped | out | Current position in local frame from EKF2 with ROS 2 timestamp |
PX4 internally uses a NED frame convention, i.e., with the Z axis pointing downwards. ROS 2, as well as many other software, prefers to express data using an NWU convention, i.e., with the Z axis pointing upwards. This package publishes data in both ways, meaning:
- Raw data that mirrors PX4 internal uORB topics is left untouched, i.e., in NED.
- Data that is generated, or converted in common formats by the Agent node is converted to NWU.
Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
Copyright (c) 2024, dotX Automation s.r.l.
Copyright (c) 2017, Proyectos y Sistemas de Mantenimiento SL (eProsima)
Copyright (c) 2018-2021, PX4 Development Team