Mastering ROS for Robotics Programming - Second Edition

Working with ROS actionlib

In ROS services, the user implements a request/reply interaction between two nodes, but if the reply takes too much time or the server is not finished with the given work, we have to wait until it completes, blocking the main application while waiting for the termination of the requested action. In addition, the calling client could be implemented to monitor the execution of the remote process. In these cases, we should implement our application using actionlib. This is another method in ROS in which we can preempt the running request and start sending another one if the request is not finished on time as we expected. Actionlib packages provide a standard way to implement these kinds of preemptive tasks. Actionlib ...