Autonomous Navigation with TurtleBot3 in Gazebo

Task Overview

This task involves using TurtleBot3 for autonomous navigation in a Gazebo simulation environment using ROS default planners. The steps include creating a map of the environment, traversing autonomously from point A to point B, and visualizing the robot's environment using RViz.

Prerequisites

Ensure you have the following software installed:

ROS (Robot Operating System)
Gazebo
TurtleBot3 packages
Git

Setup

Clone the project repository:

git clone https://github.com/rishang19dx/Task_1_Autonomous_Navigation.git
cd Task_1_Autonomous_Navigation

Install Required Packages

Make sure all dependencies are installed. If not, follow these steps:

Install ROS and TurtleBot3 Packages:

sudo apt-get update
sudo apt-get install ros-noetic-desktop-full
sudo apt-get install ros-noetic-turtlebot3 ros-noetic-turtlebot3-simulations

Set Up Workspace:

mkdir -p ~/ws/src
cd ~/ws/
catkin_make
source devel/setup.bash

Mapping the Environment

Launch Gazebo World and TurtleBot3:

export TURTLEBOT3_MODEL=burger
roslaunch turtlebot3_gazebo turtlebot3_world.launch

Creating and saving the map:

Mapping the environment manually with teleoperation proved to be a bulky task to me. Hence, I used a plugin which creates 2D occupancy map of the world at a given height

To include the plugin, add the following line in between the tags of your Gazebo world file:

<plugin name='gazebo_occupancy_map' filename='libgazebo_2Dmap_plugin.so'>
    <map_resolution>0.1</map_resolution> <!-- in meters, optional, default 0.1 -->
    <map_height>0.3</map_height>         <!-- in meters, optional, default 0.3 -->
    <map_size_x>100</map_size_x>          <!-- in meters, optional, default 10 -->
    <map_size_y>100</map_size_y>          <!-- in meters, optional, default 10 -->
    <init_robot_x>0</init_robot_x>          <!-- x coordinate in meters, optional, default 0 -->
    <init_robot_y>0</init_robot_y>          <!-- y coordinate in meters, optional, default 0 -->
</plugin>

To generate the map, call the /gazebo_2Dmap_plugin/generate_map ros service:
```
rosservice call /gazebo_2Dmap_plugin/generate_map
```
The generated map is published on the /map2d ros topic.
You can use the map_saver node from the map_server package inside ros navigation to save your generated map to a .pgm and .yaml file:
```
rosservice call /gazebo_2Dmap_plugin/generate_map
rosrun map_server map_saver -f hospital /map:=/map2d
```
The last map generated with the /gazebo_2Dmap_plugin/generate_map call is saved.