Location:Training / Embedded Development / PX4 Firmware Secondary Development Course / UORB message subscription and publishing basics

PX4 consists of two main parts: the flight stack, which mainly includes state estimation and flight control systems; and the middleware, which is a general robotics application layer that supports any type of autonomous robot and is mainly responsible for the robot's internal/external communication and hardware integration.

All drone models supported by PX4 (including other platforms such as unmanned ships, unmanned vehicles, and unmanned underwater vehicles) share the same code base. The entire system adopts a reactive design, which means that

all functions can be divided into several replaceable and reusable components.
Communication is carried out through asynchronous messaging.
The system can cope with different workloads.