ROS, a software platform for robotics

The previous section identifies the middleware as the software piece ensuring data flow between functional components, and allowing their control.

ROS is a widely known software platform in robotics, providing not only a middleware, but also implementing a wide range of commonly-used functionalities into software components (such as localisation, mapping, path-planning, obstacle avoidance, etc.), with a build system and a packaging system for easy compilation and installation. ROS benefits from a large community of users and developers, and runs on many robots today. This makes ROS a common choice as a robotic software platform, as it is for Two!Ears.

ROS embraces the principles of component-based software architectures, allowing distributed computation, software reuse and rapid testing [Kane2014]. If you will be a user of a robotic platform running ROS, the core tutorials can help you to get familiar with the ROS environment. The main ROS terminology, introduced in the tutorials, is recalled here:

Software components using ROS middleware are called ROS nodes.
Topics and messages
Data flows are called topics. A node that outputs data publishes on a topic. A node that inputs data subscribes to a topic. The data elements flowing on topics are called messages. Each message is made of various data fields forming part of a data structure called message type. As a given topic only carries one message type, the term topic type is equally used.
Services and actions
Nodes can provide services to control them. Some special services that can take a long time to execute are called actions.


In spite of its name, ROS does not replace, but instead works alongside a traditional operating system. As it provides features such as hardware abstraction and low-level device control [ros], ROS has some similarities with an OS (Operating System), hence its name.

[Kane2014]Jason M. O’Kane. A Gentle Introduction to ROS., 2014.