ROS 2

ROS 2 is a powerful general purpose robotics library that can be used with the PX4 Autopilot to create powerful drone applications.

WARNING

Tip The PX4 development team highly recommend that you use/migrate to this version of ROS!

This is the newest version of ROS (Robot Operating System). It significantly improves on ROS "1", and in particular allows a much deeper and lower-latency integration with PX4.

ROS得益于一个活跃的生态系统，在这个生态系统里，开发者会解决常见的机器人问题，他们也有权使用为Linux编写的其他软件库。 It can be used, for example, for computer vision solutions.

ROS 2 enables a very deep integration with PX4, to the extent that you can create flight modes in ROS 2 that are indistinguisable from internal PX4 modes, and directly read from and write to internal uORB topics at high rate. It is recommended (in particular) for control and communication from a companion computer where low latency is important, when leveraging existing libraries from Linux, or when writing new high level flight modes.

Communication between ROS 2 and PX4 uses middleware that implements the XRCE-DDS protocol. This middleware exposes PX4 uORB messages as ROS 2 messages and types, effectively allowing direct access to PX4 from ROS 2 workflows and nodes. 中间件使用 uORB 消息定义生成代码来序列化和反序列化来处理PX4 的收发消息。 These same message definitions are used in ROS 2 applications to allow the messages to be interpreted.

INFO

ROS 2 can also connect with PX4 using MAVROS instead of XRCE-DDS. This option is supported by the MAVROS project (it is not documented here).

To use the ROS 2 over XRCE-DDS effectively, you must (at time of writing) have a reasonable understanding of the PX4 internal architecture and conventions, which differ from those used by ROS. 我们计划近期提供ROS 2 API 以对 PX4 的特性进行封装，并举例说明它们的用途。

Topics

本节的主要主题是：

• ROS 2 User Guide: A PX4-centric overview of ROS 2, covering installation, setup, and how to build ROS 2 applications that communicate with PX4.
• ROS 2 Offboard Control Example: A C++ tutorial examples showing how to do position control in offboard mode from a ROS 2 node.
• ROS 2 Multi Vehicle Simulation: Instructions for connecting to multipole PX4 simulations via single ROS 2 agent.
• PX4 ROS 2 Interface Library: A C++ library that simplies interacting with PX4 from ROS 2. Can be used to create and register flight modes wrtten using ROS2 and send position estimates from ROS2 applications such as a VIO system.
• ROS 2 Message Translation Node: A ROS 2 message translation node that enables communcation between PX4 and ROS 2 applications that were compiled with different sets of messages versions.

更多信息

• XRCE-DDS (PX4-ROS 2/DDS Bridge): PX4 middleware for connecting to ROS 2.