ROS Robotics By Example - Second Edition

ROS nodes, topics, and messages

Here we will explore some of the main components of ROS. One of the primary purposes of ROS is to facilitate communication between the ROS nodes. These nodes represent the executable code. The code can reside entirely on one computer, or nodes can be distributed between computers or between computers and robots. The advantage of this distributed structure is that each node can control one aspect of a system.

For example, one node can capture the images from a camera and send the images to another node for processing. After processing the image, the second node can send a control signal to a third node for controlling a robotic manipulator in response to the camera view.

The main mechanism used by ROS nodes to communicate ...