ROS2 Voronoi Multi-Robot Exploration

⚠️ Work in Progress
This setup is currently under active development.

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Overview

This project aims to use a Voronoi-partition-based exploration algorithm to enable multiple robots to autonomously navigate and explore an environment.

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Requirements

• ROS2 Humble
• TurtleBot Packages
  • turtlebot4 (for TurtleBot 4)
  • turtlebot3 (for TurtleBot 3)

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Installation

Clone and build the workspace:

git clone https://github.com/akifbayram/ros2_voronoi.git
cd ~/ros2_voronoi
colcon build

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TurtleBot3 Simulation

1. Launch Simulation and Map Merge Node:

   This launch file starts a Gazebo simulation with a specified number of TurtleBot3 robots. Each robot runs its own SLAM Toolbox node and contributes to a unified merged map. It establishes static transforms from the global map frame to each robot’s namespace based on the robot_count parameter.

   cd ~/ros2_voronoi &&
   source install/setup.bash &&
   ros2 launch voronoi tb3.launch.py robot_count:=3

2. Start Exploration:

   cd ~/ros2_voronoi &&
   source install/setup.bash &&
   ros2 run voronoi voronoi_tb3 

   Alternatively, ros2 run voronoi voronoi_tb3_frontier can be used which utilizes frontier-based exploration with voronoi partitioning, closely aligning to the algorithm described in the research paper.

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Unitree Go2

1. Launch go2_ros2_sdk:

   Requires go2_ros2_sdk

   cd ~/ros2_ws &&
   source install/setup.bash &&
   export ROBOT_IP="robot_ip" &&
   export CONN_TYPE="webrtc" &&
   ros2 launch go2_robot_sdk robot.launch.py

2. Start launch script:

   This launch file starts the merge_map node to merge the robot maps and establishes static transforms from the global merged map frame to each robot's individual namespace, based on the user-defined robot_count.

   cd ~/ros2_voronoi &&
   source install/setup.bash &&
   ros2 launch go2.launch.py

3. Begin Exploration:

   cd ~/ros2_voronoi
   source install/setup.bash &&
   ros2 run voronoi voronoi_go2 

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Known Issues

• voronoi_tb3:

  • Robots remain stationary after detecting an obstacle and fail to replan.
  • Robot namespace and count are hardcoded in the script.
  • Information nodes have not been implemented.
  • Does not explicitly consider communication range constraints when determining neighboring robots.

• tb3.launch.py

  • TODO: Utilize Nav2 instead of manual navigation.

• voronoi_go2: Untested

• tb4.launch.py: Users may experience intermittent issues with launching SLAM, Nav2, or RViz for additional TurtleBot4 units.

  • Nav2 Stalling on Multiple Robots
  • SLAM with namespaced Robots
  • gazebo ignition simulation crashes when trying to simulate multiple turtlebot4

Acknowledgments

This project draws inspiration and code from the following repositories:

1. abdulkadrtr/ROS2-FrontierBaseExplorationForAutonomousRobot:
   For path planning, following, obstacle avoidance, and frontier-based exploration.

2. abdulkadrtr/mapMergeForMultiRobotMapping-ROS2: For multi robot map merging.

3. Connected-and-Autonomous-Systems-Lab/Voronoi:
   Provides the Voronoi-based exploration algorithm used in this project.

   • This repository is itself adapted from Peace1997/Voronoi_Based_Multi_Robot_Collaborate_Exploration_Unknow_Enviroment

Transform Tree

The following transform tree is produced using the tb3.launch.py launch file.