Objectives

The purpose of this homework is to gain experience writing simple ROS nodes in Python. This is an individual assignment.

This assignment will not require the use of the Turtlebot's, so you should be able to complete it outside of the lab.

Instructions

• When working on this assignment don't check out your group's subversion repository. This is an individual assignment. You'll only be editing and submitting one file, so you should be able to store it on a thumb drive or email it to yourself when you are finished working on it.
• Download the following .zip file and unzip it in the cs480_ws directory: hw1.zip.
• Now type the following into a terminal:

  roslaunch hw1 hw1.launch
  

  you should see the turtle simulator appear, along with some text output including the following:

  process[mover-2]: started with pid [18124]
  [ERROR] [WallTime: 1358457906.856196] HW1 Node not yet completed!
  [mover-2] process has finished cleanly
  

• Modify the file nodes/hw1.py so that it satisfies the following requirements:

  • It should read the the /goal parameter from the parameter server. This parameter will contain a two-entry list, where the first entry represents the target x position and the second entry represents the target y position.

    Check out these documents for more information on working with parameters:

    • http://www.ros.org/wiki/ROS/Tutorials/UnderstandingServicesParams
    • http://www.ros.org/wiki/rospy/Overview/Parameter%20Server
  • Move (don't teleport!) the turtle to the goal position.
• Make sure that navigation code works for arbitrary goal positions. (The goal position is specified in the launch file.)

That's it! Submit your finished hw1.py file through blackboard.