rs1_environment

A ROS 2 package providing custom Gazebo Ignition v6.17 simulation environments and models for use in 41068 Robotics Studio 1.

Overview

This package contains custom worlds, models, and launch configurations for Gazebo Ignition simulations. It includes AprilTags and environmental elements designed for autonomous robot navigation and perception testing.

Package Structure

rs1_environment/
├── config/          # Configuration files (YAML, etc.)
├── launch/          # Python launch scripts for starting simulations
├── models/          # Custom Gazebo models and assets
├── worlds/          # Custom world files (.sdf) for Gazebo Ignition
├── images/          # Photos of the custom world 
├── CMakeLists.txt   # Build configuration
├── package.xml      # Package metadata
└── README.md        # This file

Quick Start

1. Build the Package

cd ~/your_workspace
colcon build --packages-select rs1_environment
source install/setup.bash

2. Launch Simulation

# Launch the simulated environment
ros2 launch rs1_environment spawn_environment.launch.py

# Launch with specific world
ros2 launch rs1_environment spawn_environment.launch.py world:=world_name # Check Launch file for options

3. View in RQT

# Launch RQT - Check if you're subscribed to image topics for the drone (rs1_drone_n/front/image)
rqt 

Models

AprilTags

• Location: models/tags/
• Families: tag36h11
• IDs: 0-99 available
• Usage: Autonomous detection and localization - respond to "scenario"

Environment Objects

• Location: models/
• Types: Obstacles, landmarks, terrain features

Launch Files

The launch/ directory contains Python launch scripts:

• spawn_environment.launch.py : Launches the default world, world_1

The world argument can be edited to change world selection.

Launch Arguments

Common arguments supported by launch files:

• world: Specify which world file to load

Example:

ros2 launch rs1_environment spawn_environment.launch.py world:=world_1 # By Default, it is world_1 anyway

Development

Adding New Worlds

1. Create your world file in worlds/:

   <?xml version="1.0" ?>
   <sdf version="1.9">
     <world name="world_name_goes_here">
       <!-- Your world content and properties -->
     </world>
   </sdf>

2. Create or edit corresponding launch file in launch/:

   • Check launch/ for spawn_environment.launch.py example.
   • Worlds can be added to launch by including in the following section below:

   # Start Gazebo to simulate the robot in the chosen world
           world_launch_arg = DeclareLaunchArgument(
           'world',
           default_value='world_1',
           description='Which world to load',
           choices=['mountain_forest', 'test', 'world_1'] # Add more worlds here , seperated by commas
           )

Adding New Models

1. Create model directory: models/model_name/
2. Add required files:
   • model.sdf: Model definition
   • model.config: Model metadata
   • materials/: Textures and materials (For AprilTags, other models have the texture in the meshes directory)

Creating Custom AprilTags

1. Generate tag images using online generators i.e. using https://chev.me/arucogen/
2. Place converted PNG files in models/tags/tag_X/materials/textures/
3. Update albedo map referencing in your AprilTag model SDF files

Environment/World Photos

• World_1 AprilTag cube with the size 3x3x3 compared to 1x1x1

• World_1 Top_Down View

Troubleshooting

Common Issues

Gazebo Mesh not Found

• Verify mesh files if it is valid and not corrupt, re-export mesh file into the meshes directory of the model

Gazebo Doesn't load texture

• Verify texture for the mesh is in the same directory or is mapped properly in Blender.
• Import the exported .dae mesh to verify if texture is properly mapped to mesh and loads.
• Ensure file name referencing are correct in .dae - check using VsCode

Gazebo Doesn't Run / is Frozen

• Reset Gazebo GUI

Acknowledgments

• AprilTag library by University of Michigan and AprilTag generation using https://chev.me/arucogen/
• Gazebo Ignition simulation framework
• ROS 2 community and 41068 Ignition Bringup Package from 41068 RS1 2025 Spring