example templates for python ROS nodes

• Creating a package:

  • Assumes you have ROS installed and have created a catkin_ws
  • https://wiki.ros.org/ROS/Tutorials/catkin/CreatingPackage

• Pulling code from github

  • Cd into new package you created above
  • enter: git clone https://github.com/agillies8/node_templates
  • cd to catkin_ws && Catkin_make
  • Change file permissions: chmod +x for all python files in /src

• publisher.py:

  • Review main components
  • Start roscore
  • run the node: rosrun node_templates publisher.py
  • Rostopic echo mymessage in new terminal
  • Change message and observe
  • Add a counter publisher
  • Observe as above with rostopic echo

• subscriber.py:

  • Review main components
  • make sure roscore is still running
  • run the publisher as above
  • run the subscriber: rosrun node_templates subscriber.py
  • Interrogate result
  • Add int to subscriber

• SubNpub.py:

  • Review main components
  • Start node
  • Publish int from command line: “rostopic pub number1 std_msgs/Int16 "1"”
  • View results

• create and use a ros service:

  • Create a service: https://wiki.ros.org/ROS/Tutorials/CreatingMsgAndSrv#Creating_a_srv
  • Create a service server and client: https://wiki.ros.org/ROS/Tutorials/WritingServiceClient%28python%29
  • Run and examine:
    • rosrun node_templates serviceServer.py
    • rosrun node_templates serviceClient.py 2 3

• Call an action server: https://wiki.ros.org/actionlib_tutorials/TutorialsReview the docs: https://wiki.ros.org/actionlib_tutorials/Tutorials

  • Review server:
  • Review client: https://docs.ros.org/en/jade/api/actionlib/html/classactionlib_1_1simple__action__client_1_1SimpleActionClient.html
  • Send message and wait for goal
  • Preempt a goal
  • interrogate an action while is is executing