TurtleBot3 A* Path Planning with Dynamic Obstacle Avoidance (ROS2)

This project implements an A* path planner as a ROS2 plugin for TurtleBot3 in Gazebo simulation.  
It demonstrates real-time path replanning when obstacles appear dynamically in the environment.

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Project Structure
tb3_ws/
├── src/
│   ├── tb3_astar_planner/     (A* path planning plugin)
│   ├── tb3_launch/            (Launch files for simulation)
│   └── tb3_world/             (World + Map files: YAML + PGM)
├── install/
├── build/
├── log/
└── README.md

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Features
* A* based path planner integrated with Nav2
* Runs on TurtleBot3 in Gazebo
* Dynamic replanning when obstacles are introduced
* Customizable environment (maps/worlds)

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Setup Instructions

# 1. Install ROS2 Jazzy
#    Follow official ROS2 Jazzy install guides for Ubuntu 24.04
sudo apt update
sudo apt install ros-jazzy-desktop  # or similar metapackage

# 2. Install other required ROS2 / Gazebo / Nav2 components
sudo apt install ros-jazzy-navigation2 ros-jazzy-slam-toolbox
# Also, Gazebo / ros-gz packages
sudo apt install ros-jazzy-gazebo* ros-jazzy-ros-gz*

# 3. Setup your workspace
mkdir -p ~/tb3_ws/src
cd ~/tb3_ws/src

# 4. Clone required repos from source
git clone https://github.com/ROBOTIS-GIT/turtlebot3_msgs.git         # check branch or tags
git clone https://github.com/ROBOTIS-GIT/turtlebot3.git              # contains URDF/Xacro, etc.
git clone https://github.com/ROBOTIS-GIT/turtlebot3_simulations.git  # worlds, Gazebo models

2. Clone the Repository

cd ~
git clone https://github.com/RRG2003/TurtleBot3-Dynamic-Navigation-with-A-Planner-ROS-2-Jazzy.git
cd tb3_ws

3. Build the Workspace

colcon build --symlink-install
source install/setup.bash

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How to Run

Step 1: Launch TurtleBot3 in Gazebo

ros2 launch tb3_dynamic_nav_jazzy tb3_gz_nav.launch.py

Step 2: Launch Navigation Stack with A* Planner (Open a new terminal, source the workspace, and run:)

source ~/tb3_ws/install/setup.bash
ros2 launch nav2_bringup bringup_launch.py use_sim_time:=True map:=$HOME/tb3_ws/src/tb3_world/maps/map_1758046643.yaml

Step 3: Send Navigation Goal Open RViz2 Use the 2D Nav Goal tool to set a target position The robot will:

1. Plan a path using A*
2. Navigate to the goal
3. Replan dynamically if new obstacles are introduced in Gazebo

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Demonstration

1. Robot navigates to a goal with no obstacles
2. An obstacle is added mid-path
3. The planner recomputes a new path and avoids the obstacle

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Deliverables

1. Complete ROS2 Workspace (this repo) with launch files
2. Demonstration Video showing obstacle avoidance
3. One-Pager (Performance Analysis, Documentation, Challenges)

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Performance Analysis

• A* guarantees an optimal path (given grid discretization)
• Real-time replanning ensures safe navigation when obstacles appear
• Tested in Gazebo with TurtleBot3 Burger model

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Challenges Faced

• Plugin integration with Nav2 required tuning
• Handling dynamic obstacles needed map updates + replanning triggers
• Real-time replanning introduces computational overhead for large maps

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Author Rishabh Jain Graduate Engineer | Robotics & Autonomous Systems