9  Ros2 Concepts

Important

You are reading the work-in-progress edition of ROS 2 : Mea Via et Mea Disciplina. This chapter is currently a dumping ground for ideas, and we don’t recommend reading it. The complete version will be available here soon. Stay tuned!

ROS2-Concept	Description
Nodes	A node is a process that performs a specific task, such as sensing or actuating. Nodes can communicate with each other by sending and receiving messages over topics.
Topics	A topic is a named bus over which nodes can publish and subscribe to messages. Topics are used for one-to-many communication.
Services	A service is a request-response communication model between nodes. A node can make a request to a service and receive a response from it.
Actions	Actions are similar to services, but they allow for more complex communication patterns, such as canceling a request or providing feedback during the execution of a request.
Parameters	Parameters are key-value pairs that can be used to configure nodes and their behavior.
Launch files	A launch file is an XML file that specifies how to start multiple nodes with their respective parameters and configurations.
RQT	RQT is a collection of ROS graphical tools for debugging, monitoring, and visualizing ROS topics, nodes, and messages.
RViz	RViz is a 3D visualization tool for ROS that allows users to display and interact with sensor data and robot models in real-time.
tf2	tf2 is a library for keeping track of coordinate frames over time. It provides a way to transform data between different coordinate frames in a robot system.
ROS2 Middleware	ROS2 Middleware is the layer of software that provides the communication infrastructure between nodes. ROS2 provides multiple middleware options, such as Fast RTPS and Cyclone DDS.