Learning Robotics using Python - Second Edition

The ROS Computation Graph

The ROS Computation Graph is the peer-to-peer network of ROS systems that processes data. The basic features of ROS Computation Graph are nodes, ROS Master, the parameter server, messages, and services:

• Nodes: The ROS node is a process that uses ROS functionalities to process the data. A node basically computes. For example, a node can process the laser scanner data to check whether there is any collision. A ROS node is written with the help of an ROS client library (such as roscpp and rospy), which will be discussed in the upcoming section.
• ROS Master: The ROS nodes can connect to each other using a program called ROS Master. This provides the name, registration, and lookup to the rest of the computation graph. ...