In this chapter, we will see some of the advanced concepts in ROS such as the ROS pluginlib, nodelets, and Gazebo plugins. We will discuss the functionalities and applications of each concept and will look at an example to demonstrate it's working. We have used Gazebo plugins in the previous chapters to get the sensor and robot behavior inside the Gazebo simulator. In this chapter, we are going to see how to create it. We will also discuss an modified form of ROS nodes called ROS nodelets. These features in ROS are implemented using a plugin architecture called pluginlib.

In this chapter, we will discuss the following topics:

• Understanding pluginlib
• Implementing a sample plugin using pluginlib
• Understanding ROS nodelets
• Implementing a sample nodelet
• Understanding and creating a Gazebo plugin