TurtleBot3 Obstacle Avoidance with SLAM

An autonomous navigation system for TurtleBot3 that explores unknown environments while avoiding obstacles and building a map in real-time.

Overview

This project implements a reactive obstacle avoidance behavior for TurtleBot3 robots using ROS2. The robot navigates autonomously by processing laser scan data, making real-time navigation decisions, and simultaneously creating a map of the environment using SLAM Toolbox.

Features

• Real-time obstacle detection using 360° laser scanner
• Smart navigation - robot turns toward open space when obstacles detected
• Simultaneous mapping with SLAM Toolbox integration
• Automatic recovery - switches direction if stuck
• Fully configurable parameters via YAML file
• Timed launch system - coordinated startup of all components
• RViz2 visualization - live view of robot state and map

How It Works

The robot divides its field of view into three sectors:

• Front Center (-20° to +20°): Detects obstacles directly ahead
• Front Left (+20° to +80°): Checks left side clearance
• Front Right (-80° to -20°): Checks right side clearance

Navigation Logic:

1. If front is clear → Move forward at 0.15 m/s
2. If obstacle detected within 0.6m → Stop and turn toward the side with more space
3. If turning for >3 seconds → Try opposite direction
4. Repeat

Requirements

• ROS2 (Humble/Foxy or later)
• TurtleBot3 packages
• Gazebo simulator
• SLAM Toolbox
• RViz2

Installation

# Clone this repository into your ROS2 workspace
cd ~/ros2_ws/src
git clone <your-repo-url>

# Install dependencies
cd ~/ros2_ws
rosdep install --from-paths src --ignore-src -r -y

# Build the package
colcon build --packages-select tb3_obstacle_avoidance

# Source the workspace
source install/setup.bash

Usage

Launch the complete simulation (Gazebo + SLAM + Obstacle Avoidance + RViz):

ros2 launch tb3_obstacle_avoidance sim_tb3_avoidance.launch.py

Optional arguments:

ros2 launch tb3_obstacle_avoidance sim_tb3_avoidance.launch.py model:=waffle

What happens:

• t=0s: Gazebo launches with TurtleBot3 World
• t=5s: RViz2 opens with mapping visualization
• t=15s: Robot starts moving autonomously

Configuration

Edit config/obstacle_avoidance.yaml to adjust parameters:

obstacle_avoidance:
  ros__parameters:
    # Speed settings
    linear_speed: 0.15        # Forward speed (m/s)
    angular_speed: 0.6        # Turning speed (rad/s)
    
    # Detection
    obstacle_distance: 0.6    # Trigger distance for avoidance (m)
    
    # Timing
    startup_delay_sec: 1.0    # Delay before movement starts

Project Structure

tb3_obstacle_avoidance/
├── src/
│   └── obstacle_avoidance_node.cpp    # Main navigation logic
├── launch/
│   └── sim_tb3_avoidance.launch.py    # Launch file
├── config/
│   ├── obstacle_avoidance.yaml        # Parameters
│   └── rviz/
│       └── tb3_mapping.rviz           # RViz config
├── CMakeLists.txt
└── package.xml

Key Concepts Demonstrated

• ROS2 node development in C++
• Laser scan data processing
• Reactive navigation strategies
• SLAM integration for mapping
• Parameter-based configuration
• Multi-node launch coordination

Limitations

• Purely reactive behavior (no path planning)
• May get stuck in complex obstacle configurations
• No goal-directed navigation
• Assumes static environment