Autonomous SLAM using a differential drive robot. This work is a project for Introduction to Robotics class.

Overview

There are two videos showing the whole setup in action: Building a map of the environment | ROS Gmapping | Octomap and Autonomous Robot navigation using the ROS Navigation.

Prerequisites

This project was developed for ROS Noetic (Ubuntu 20.04). The following packages are required:

1. pointcloud_to_laserscan package, is used to convert a 3D Point Cloud into a 2D laser scan, this can be installed using: sudo apt install ros-noetic-pointcloud-to-laserscan ros-noetic-rosbridge-server

2. To control the robot, you might need to install the teleop_twist_keyboard package and then run teleop_twist_keyboard teleop_twist_keyboard.py.

3. OctoMap is used to generate the 3D occupancy grid. octomap_server is used to interface OctoMap with ROS, both can be installed via apt as ros-noetic-octomap and ros-noetic-octomap-ros.

4. You'll need to install the OctoMap RViz plugin via apt as ros-noetic-octomap-rviz-plugins. Without it, occupancy grid visualisations in RViz will not work.

5. You will also need to install the controller_manager package: sudo apt-get install ros-noetic-controller-manager

6. The probabilistic localization system amcl is also needed, you can install it with: sudo apt install ros-noetic-amcl

Note: you might need to install more packages depending on what you have previously installed, if you have any problem just google it, and install the package needed.

Usage

1. Make sure you have the prerequisites installed.
2. Clone this repo into your catkin workspace, e.g. into ~/catkin_ws/src/navros_pkg/.
3. Clone aws-robomaker-small-house-world repo into your catkin workspace, e.g. into ~/catkin_ws/src/small-house-world/.
   • Add the following to your launch file:

<launch>
  <!-- Launch World -->
  <include file="$(find aws_robomaker_small_house_world)/launch/small_house.launch"/>
  ...
</launch>

4. Source your ROS in the Bash instance: source /opt/ros/noetic/setup.bash and source ~/catkin_ws/devel/setup.bash.
5. Run catkin_make in ~/catkin_ws/ and source ~/catkin_ws/devel/setup.bash again.

Start Gazebo Simulation

6. Start the simulation using: roslaunch aws_robomaker_small_house_world view_small_house.launch.
7. Spawn the robot in the map using: roslaunch navros_pkg urdf_gazebo_view.launch. Keep this terminal running for all the next steps.

Mapping

3D occupancy grid map	2D occupancy grid map

8. Run the gmapping SLAM command:roslaunch navros_pkg gmapping.launch
9. Navigate to rviz folder using:cd catkin_ws/src/navros_pkg/rviz then run it using: rviz -d map.rviz
10. For OCTOMAP use:roslaunch navros_pkg octomap.launch Then navigate to rviz folder using:cd catkin_ws/src/navros_pkg/rviz then run it using: rviz -d octomap.rviz
11. To control the drone manually, you use: rosrun teleop_twist_keyboard teleop_twist_keyboard.py but it requires teleop_twist_keyboard package to be installed.
12. Once mapping is complete, Save the map: rosrun map_server map_saver ~/catkin_ws/src/navros_pkg/maps/name_of_map if this command is not working for some reason, then run this rosrun map_server map_saver then copy the map generated in src directory to ~/catkin_ws/src/navros_pkg/maps/ directory. Finally close everything, and relaunch gazebo only with the robot (repeat steps 6 and 7).

Autonomous Navigation

13. To start the navigation using the previously generated map, run each of the following commands in a new terminal:

• A) roslaunch navros_pkg amcl.launch map:='name_of_map' if you picked a name for your map make sure to change name_of_map otherwise it should be map (check the name in the maps folder).
• B) roslaunch navros_pkg move_base.launch
• C) cd catkin_ws/src/navros_pkg/rviz then rviz -d navigate.rviz

14. Test navigation using rviz:

• Set initial pose (Click "2D pose estimate" and pinpoint the approximate location of robot on map).*
• Red arrows indicate the probable location.
• Set goal for the robot in RVIZ (Click "2D Nav goal" and pinpoint the desired goal on the map).
• Green line indicates the path planned.

15. Thanks and PROFIT