Husky Frontier Exploration Demo

This tutorial shows you how to use move_base with gmapping and frontier_exploration to perform autonomous planning movement, and exploration with simultaneous localization and mapping (SLAM), on a simulated Husky, or a factory-standard Husky with a laser scanner publishing on the scan topic.

To adapt this demo to your own Husky, you may need to clone the husky_navigation repository, and modify the relevant parameters. To learn about move_base, gmapping, frontier_exploration and the navigation stack, see the Navigation Tutorials.

Preparation

Warning

The frontier_exploration package is no longer officially supported in ROS Melodic. These instructions require building the package from source. Because the package is no longer officially supported support for any issues you encounter will be limited.

First, you must build the frontier_exploration package from source. Create a catkin workspace and cd into it (or cd into an existing workspace if you already have one) and clone the code from github:

cd ~/catkin_ws/src
git clone https://github.com/paulbovbel/frontier_exploration.git

Install any additional dependencies:

cd ~/catkin_ws
rosdep install --from-paths src --ignore-src -r -y

The make the exploration_msgs package:

catkin_make --pkg exploration_msgs

Once that package is built, source your workspace and build the rest of the package:

source devel/setup.bash
catkin_make

Make sure you have the husky_navigation package installed by running

sudo apt-get install ros-melodic-husky-navigation

Because frontier_exploration is not officially supported by ROS Melodic you will need to modify the following launch files inside the husky_navigation package:

  • launch/exploration.launch

  • launch/exploration_demo.launch

Remove the commented-out sections so that the files look like this:

exploration.launch:

<launch>

  <node pkg="frontier_exploration" type="explore_client" name="explore_client" output="screen"/>
  <node pkg="frontier_exploration" type="explore_server" name="explore_server" output="screen">
    <param name="frequency" value="1.0"/>

    <!-- Should be less than sensor range -->
    <param name="goal_aliasing" value="2.0"/>
    <rosparam file="$(find husky_navigation)/config/costmap_common.yaml" command="load" ns="explore_costmap" />
    <rosparam file="$(find husky_navigation)/config/costmap_exploration.yaml" command="load" ns="explore_costmap" />
  </node>
</launch>

exploration_demo.launch:

<launch>
  <!--- Run gmapping -->
  <include file="$(find husky_navigation)/launch/gmapping.launch" />

  <!--- Run Move Base -->
  <include file="$(find husky_navigation)/launch/move_base.launch" />

  <!-- Run Frontier Exploration -->
  <include file="$(find husky_navigation)/launch/exploration.launch" />
</launch>

Running the demo

Note

In each terminal window, make sure to source the catkin workspace where you built frontier_exploration

  1. In three separate terminal windows:

  1. Start the Clearpath-configured Husky simulation environment:

roslaunch husky_gazebo husky_playpen.launch

  1. Start the Clearpath-configured rviz visualizer:

roslaunch husky_viz view_robot.launch

  1. Start the frontier_exploration demo:

roslaunch husky_navigation exploration_demo.launch

  1. In the Rviz visualizer, make sure the visualizers in the Navigation group are enabled.

  2. Use the Point tool in the top toolbar to draw a closed polygon on the map that the Husky should explore. Watch the terminal window for instructions.

  3. As the robot moves, you should see the grey static map (map topic) grow. Occasionally, the gmapping algorithm will relocalize the robot, causing a discrete jump in the map->odom transform.

  4. When the exploration goal is complete, you will see a feedback message in the terminal window. You can now issue a new exploration goal if you wish.

  5. To save the generated map, you can run the map_saver utility:

rosrun map_server map_saver -f <filename>