2D mapping and navigation on Robotont

Now that we have tested some SLAM and navigation packages in a simulation, let’s try them out on a real robot - Robotont.

Establish connection to the robot

Since in this section we would need to open serveral terminals, let’s use the distributed ROS advantages and add the export ROS_MASTER_URI=.... command to the end of the .bashrc file. So that every time you open a new terminal it will be configured to connect to the robot.

  1. Open .bashrc for editing:

gedit ~/.bashrc

  1. Add the line export ROS_MASTER_URI=http://192.168.200.XXX:11311 to the end of the file. NB! substitute the XXX with your robot number!

  2. First, log into the robot using an SSH connection and start the mapping and localization (gmapping):

    roslaunch robotont_demos 2d_slam_create_map.launch

  3. Now let’s open up another terminal and start the teleoperation node. When ROS_MASTER_URI is succesfully set in the .bashrc file, you should be able to control the robot now.

    rosrun teleop_twist_keyboard teleop_twist_keyboard.py

  4. To visualize the mapping, you can open up rviz and manually add displays as we did for simulated robot, or you can also use a preconfigured launch file:

    roslaunch robotont_demos 2d_mapping_display.launch

  5. To save the map and run amcl, use the same commands as you did with simulated robot.

  6. To run the navigation on the Robotont, we have prepared a custom launch file. So, instead of the move_base.launch, we run:

    roslaunch robotont_demos 2d_slam_navigation.launch

Tweaking ROS Navigation parameters

Now that you have the experience of how navigation works in ROS, let’s try tuning some parameters to improve (or not) the navigation software.

In your robotont_navigation configuration folder, the relevant files are those that begin with costmap_ and planner_.

From these files, you can configure how your robot uses the navigation stack. The most important file here for you is planner_local_params.yaml. From this file, you can tune the parameters for the planner. Reference can be found here: http://wiki.ros.org/base_local_planner and here: http://wiki.ros.org/teb_local_planner.

  1. Open a new terminal and log into the robot via SSH. Use roscd to go to the robotont_navigation/config package.

  2. Now use nano to edit some of the configuration files to configure the planners and make it work better.

    What if you would change acceleration limits? What if you would try to increase or decrease the goal tolerance? What if you changed local and global map sizes in the launch file? You can use ROS Wiki to see what the parameters do and make the robot navigate more accurately.

  3. To test your new configuration, relaunch the 2d_slam_navigation.launch.

  4. If you are satisfied with the performance of your navigation, congratulations!