Objective

We want to make sure that you

• are comfortable with Linux, ROS1 and git
• have basic programming skills
• know you to document code and follow style guides

Preliminary tasks

• Do Beginner Level tutorials 1 to 17 of http://wiki.ros.org/ROS/Tutorials
• Follow installation steps required to start the husky simulator under ROS noetic

$ sudo apt install ros-noetic-gazebo-ros-* ros-noetic-lms1xx
$ cd ~/catkin_ws/src
$ git clone https://github.com/husky/husky.git
$ cd ..
$ rosdep install --from-path src --ignore-src
$ catkin build
$ source devel/setup.bash

Run the simulation

Start the main launch file for the husky robot using:

roslaunch husky_gazebo husky_empty_world.launch

The estimated location of the robot is provided by the Extended Kalman Filter output: it is published on /odometry/filtered.

$ rostopic echo /odometry/filtered

The robot velocity can be set by publishing a Twist message to /twist_marker_server/cmd_vel by:

• writing rostopic pub /twist_marker_server/cmd_vel geometry_msgs/Twist
• pressing tab twice
• setting a rate of 10 hz

You can set a forward velocity, s.a.:

$ rostopic pub /twist_marker_server/cmd_vel geometry_msgs/Twist "linear:
  x: 0.2
  y: 0.0
  z: 0.0
angular:
  x: 0.0
  y: 0.0
  z: 0.0" -r 10

Task

Write a C++ node which makes the robot drive to the point at position x = 10.0 and y = 1.0 in the odom frame.

Your node has to

• subscribe to /odometry/filtered
• publish to /twist_marker_server/cmd_vel

The correct location is reached when the robot is within 0.5 m of the target location, e.g.

$ rosrun tf tf_echo odom base_link
- Translation: [10.254, 1.324, 0.000]
- Rotation: ...

Do not write something too complex: please keep it simple.

And please follow code styles described in http://wiki.ros.org/StyleGuide, http://wiki.ros.org/CppStyleGuide and http://wiki.ros.org/PyStyleGuide.

Add a README.md

Add a README.md file describing:

• how to install the required dependencies
• what your node does
• how to use it

Upload on gitlab.com

• Create a private repository
• Push your code (you should have have more than one commit for this mini-project)
• Add maug (Maurice Gohlke) and ddimarco (Daniel Di Marco) as collaborators

Send us the link to the repository via email at maurice.gohlke@farming-revolution.com.