OHMS-NetSim: Outdoor Heterogeneous Multi-Robot System Network Simulator

OHMS-NetSim is a high-fidelity simulation framework for developing and testing algorithms for Outdoor Heterogeneous Multi-Robot Systems. Built on ROS 2 Humble and Gazebo, it provides a realistic platform for researchers to validate navigation, communication, and coordination strategies in challenging outdoor environments.

A key feature of OHMS-NetSim is its custom Gazebo plugin that simulates realistic, range-dependent communication degradation based on established scientific models, enabling the study of communication-aware robotics.

(Note: You will need to add a screenshot of your simulator to docs/images/ohms_sim_screenshot.png)

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Table of Contents

• Key Features
• Installation
• Getting Started: Running a Simulation
• Project Structure
• Community and Contribution
• Citation
• Acknowledgements

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Key Features

• Heterogeneous Teams: Simulate complex teams of Unmanned Ground Vehicles (UGVs) and Unmanned Aerial Vehicles (UAVs).
• Realistic Outdoor Worlds: Includes several pre-built environments, such as a Mars yard and dense forests of varying scales.
• Modular Scenario Definition: Easily define and launch complex multi-robot scenarios using a combination of YAML configuration files and ROS 2 launch files.
• Scientifically-Grounded Comms Emulation: A custom Gazebo plugin simulates path loss and packet drop rates based on peer-reviewed models, allowing for realistic testing of communication-aware algorithms.
• ROS 2 Humble Integration: Fully integrated with the ROS 2 ecosystem, providing a standard platform for robotics research and development.

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Installation

These instructions assume you are using Ubuntu 22.04 with ROS 2 Humble Hawksbill installed.

1. Prerequisites

• ROS 2 Humble: Ensure you have a working installation of ROS 2 Humble. You can follow the official installation guide here.
• Gazebo Fortress: OHMS-NetSim uses Gazebo (formerly Ignition Gazebo). The required version, Fortress, is typically installed as a dependency of ROS 2 Humble (ros-humble-ros-gz).
• Colcon: The standard ROS 2 build tool.
• Git: For cloning the repository.

2. Build Instructions

1. Create a Colcon Workspace: If you do not have one already, create a new ROS 2 workspace.

   mkdir -p ~/ros2_ws/src
   cd ~/ros2_ws

2. Clone the Repository: Clone this repository into your workspace's src directory.

   git clone <your-repository-url> src/ohms_sim

3. Install Dependencies: Use rosdep to install any missing dependencies.

   rosdep install -i --from-path src -y --rosdistro humble

4. Build the Workspace: Build the ohms_sim package using colcon.

   colcon build --packages-select ohms_sim

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Getting Started: Running a Simulation

Once the package has been built successfully, you can run the various simulation scenarios.

1. Source the Workspace: Before running any ROS 2 commands, you must source the workspace's setup file in every new terminal.

   source ~/ros2_ws/install/setup.bash

2. Launch a Simulation: Use the ros2 launch command to start a simulation. Several pre-configured scenarios are available.

   • Example 1: Single UGV in a Forest This will launch a single Husky UGV in the forest world.

     ros2 launch ohms_sim single_robot_sim.launch.py world:=forest

   • Example 2: Dual UGV-UAV Team This launches a team consisting of one Husky UGV and one X4 UAV.

     ros2 launch ohms_sim dual_robot_uav_ugv_sim.launch.py world:=forest

   • Example 3: Large Heterogeneous Team This launches a team of two UGVs and two UAVs in a larger, denser forest environment.

     ros2 launch ohms_sim multi_robot_2uav_2ugv_sim.launch.py world:=forest5x

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Project Structure

The repository is organised to allow for easy customisation and extension.

• /launch: Contains the top-level ROS 2 launch files for starting different simulation scenarios.
• /config: Holds the YAML files used to configure the parameters for each simulation, such as robot names, initial poses, and sensor loadouts.
• /worlds: Contains the Gazebo .sdf world files.
• /models: Contains the Gazebo .sdf model files for the robots and other objects in the world.
• /src: Contains the C++ source code for the CommsEmulatorHelper Gazebo plugin.
• /docs: Contains detailed project documentation, including the project roadmap.

To create a new scenario, you can create a new YAML file in the /config directory and a corresponding launch file in the /launch directory.

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Community and Contribution

We welcome contributions from the community! Whether you are reporting a bug, suggesting a new feature, or submitting code, your input is valuable. Please consult our community guidelines to get started.

• Project Roadmap: Outlines our phased release plan, from the current prototype to future stable versions.
• Contribution Guidelines: Explains how to contribute to the project.
• Code of Conduct: Our commitment to a welcoming and inclusive community.

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Citation

If you use OHMS-NetSim in your research, please cite our work. (Please add your publication details here once available)

@inproceedings{your-lastname-2025-ohms,
  title     = {OHMS-NetSim: An Outdoor Heterogeneous Multi-Robot System Simulator for Communication-Aware Robotics},
  author    = {Your Name and Co-authors},
  booktitle = {Name of Conference or Journal},
  year      = {2025},
  address   = {City, Country}
}

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Acknowledgements

The simulation worlds marsyard2020, marsyard2020forest, and marsyard2020forest5x are adapted from the leo_simulator-ros2 package, developed by the Mars Society Polska and the Leo Rover team. We extend our gratitude for their excellent work.

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