FEUP-RI-PROJ

Project Description
Folder Structure & ROS Packages
- my_reactive_robot
- my_controller
The Environment
Dependencies
How to Run

Project Description

This project consists of the development of a reactive robot that is able to navigate autonomously in a simulated environment. The robot is able to avoid obstacles and reach a goal position. The robot is simulated in Gazebo, and the simulation is controlled using ROS.

The environment is a question-marked world, and the robot used is a differential drive robot with a LIDAR sensor, the Turtlebot3 Burger.

Folder Structure & ROS Packages

├── README.md                   # This file.
├── report/                     # Report files
├── src
│   ├── build/                  # Build files
|   ├── install/                # Install files
│   ├── log/                    # Log files
│   ├── my_reactive_robot/      # ROS package to spawn robot and run gazebo
|   |   ├── launch/
|   |   |  ├── launch.py        # Launch file to run world
|   |   ├── worlds/
|   |   |  ├── my_world.world/  # World file
|   |   | ...
│   ├── my_controler/           # ROS package to control robot
|   |   ├── my_controller/
|   |   |  ├── controller.py    # Controller file
|   |   |  ├── ...
|   |   | ...
| ...

Two ROS packages were created, my_reactive_robot and my_controller.

my_reactive_robot

This package is responsible for spawning the robot in the world and running the simulation. The launch file is an adaptation from the file turtlebot3_world.launch from the package turtlebot3_gazebo.

Four commands are launched:

gzserver_cmd - Gazebo server for simulating physics, sensors, rendering, etc.
gzclient_cmd - Gazebo client for displaying the GUI and visualization
robot_state_publisher_cmd publishes the state of the robot
spawn_turtlebot3_cmd Spawns the robot in the world

The world file is a custom world that was created using the Gazebo GUI.

my_controller

This package is responsible for controlling the robot. The controller file is a Python script that subscribes to the topic /scan and publishes to the topic /cmd_vel. The controller uses the LIDAR sensor to detect how close the walls are.

Two nodes were created:

spin_randomly_node spins the robot randomly for 5 seconds.
scan_to_velocity_node subscribes to the topic /scan and publishes the desired velocity to the topic /cmd_vel.

When the robot first spawns, only the x and y coordinates are random, but the orientation is hard-coded. To solve this, we created the spin_randomly_node node: it spins the robot randomly for 5 seconds, and then scan_to_velocity_node takes over.

The Environment

Question mark shaped, strait line below, imperfect circle above, circle ends in round shape, bottom is straight and edgy shape.

The robot spawns in a random position and orientation inside the roundish part, at the top of the world.

Dependencies

A working installation of a ROS distribution

This project was developed using ROS2 Humble, so we can't guarantee that it will work in ROS1 distributions.

Please install the following dependencies before running the project:

turtlebot3_gazebo

sudo apt install ros-$ROS_DISTRO-turtlebot3*

gazebo_ros

sudo apt install ros-$ROS_DISTRO-gazebo-ros-pkgs.

If using ROS1, please run sudo apt install ros-$ROS_DISTRO-gazebo-ros-control as well.

How to Run

Source your ROS distribution.

Run source /opt/ros/$ROS_DISTRO/setup.bash or add this line to your .bashrc file to source it automatically on every new terminal instance.
Clone this repository.
Change into the root directory of the repository.
Run colcon build to build the packages. Add the flag --symlink-install to create a symbolic link to the packages instead of copying them.
Run source install/setup.bash to source the packages.

To avoid running this command on every new terminal instance, add this line to your .bashrc file. Modify the path accordingly.
Set up the Turtlebot3 model.

Run export TURTLEBOT3_MODEL=burger to set the model to Burger. Other possible models are waffle and waffle_pi. Add this line to your .bashrc file to avoid running it on every new terminal instance.
Set up the Gazebo model path

export GAZEBO_MODEL_PATH=$GAZEBO_MODEL_PATH:`ros2 pkg \ prefix turtlebot3_gazebo \ `/share/turtlebot3_gazebo/models/
Open two terminals.
1. In the first terminal, run ros2 launch my_reactive_robot launch.py to launch the world. Wait for the world to load.
2. In the second terminal, run ros2 run my_controller controller.py to launch the controller.

Please note that we have set up Gazebo to start in a paused state. To start the simulation, press the play button in the Gazebo GUI.

To stop the simulation, press the stop button in the Gazebo GUI, or press Ctrl+C in the terminal where the simulation was launched.

carlosverissimo3001/FEUP-RI-PROJ