Nantrobot Robot Simulation

A ROS2 simulation package for differential drive robots using Gazebo.

Installation

Prerequisites

• ROS2 jazzy (not tested on other versions, probably works on kilted and that's it)
• Gazebo

Clone the repositories

cd ~/ros_ws/src
git clone https://github.com/ECN-Nantrobot/nantrobot_robot_sim.git
git clone https://github.com/ECN-Nantrobot/nantrobot_rviz_panel.git

install dependencies

cd ~/ros_ws
rosdep install --from-paths src --ignore-src -r -y

Build the workspace

cd ~/ros_ws
colcon build

Quick start

To test if everything is working well

source ~/ros_ws/install/setup.bash
ros2 launch nantrobot_robot_sim two_robot_sim.launch.py

in another terminal

# Move the MainRobot forward
ros2 topic pub /MainRobot/cmd_vel geometry_msgs/msg/Twist '{linear: {x: 0.2, y: 0.0, z: 0.0}, angular: {x: 0.0, y: 0.0, z: 0.0}}'

Launch Files

Main Launch Files

two_robot_sim.launch.py

• Complete two-robot simulation setup with Gazebo, RViz, and all components
• The two robots are in the MainRobot and Opponent namespaces and are spawned at predefined positions
• Arguments:
  • button_config (optional): Path to button configuration file for RViz panels

if everything works weel it should look like this

start_sim.launch.py

• Launches Gazebo environment with RViz visualization and table mesh
• Arguments:
  • world (optional): Path to custom Gazebo world file
  • button_config (optional): Path to button configuration file for RViz panels
  • rviz_config (optional): Path to RViz configuration file
  • namespace (optional): Namespace for nodes (default: empty string)

spawn_robot.launch.py

• Spawns a single robot in an existing Gazebo simulation with all components
• Arguments:
  • robot_namespace (required): Namespace for the robot (e.g., "robot1", "robot2")
  • teleport_x (optional, default: 0.3): Initial X position
  • teleport_y (optional, default: 1.8): Initial Y position

rsp.launch.py

• Robot State Publisher launch file for broadcasting robot state and transforms
• Arguments:
  • use_sim_time (optional, default: false): Use simulation time if true
  • use_namespace (optional, default: ''): Namespace to launch the node into

Node Graph

Topic Interface

This package provides a complete robot simulation with the following topic interface:

Input Topics (Commands)

• /{robot_namespace}/cmd_vel (geometry_msgs/msg/Twist) - Direct velocity commands (highest priority in twist_mux) for something like a controller or teleoperation
• /{robot_namespace}/cmd_vel_tracker (geometry_msgs/msg/Twist) - Tracker velocity commands (medium priority)
• /{robot_namespace}/cmd_vel_diff_count (geometry_msgs/msg/Twist) - Navigation velocity commands (lowest priority) the topic that should be used by the navigation stack
• /{robot_namespace}/set_robot_position (geometry_msgs/msg/PoseStamped) - Teleport robot to specified pose for resetting or initialization

Output Topics (Sensor Data & State)

• /{robot_namespace}/scan (sensor_msgs/msg/LaserScan) - LIDAR scan data
• /{robot_namespace}/odom (nav_msgs/msg/Odometry) - Corrected odometry data
• /{robot_namespace}/joint_states (sensor_msgs/msg/JointState) - Joint positions and velocities
• /{robot_namespace}/robot_description (std_msgs/msg/String) - Robot URDF description
• /{robot_namespace}/camera/image_raw (sensor_msgs/msg/Image) - Camera image data (not working yet)
• /{robot_namespace}/camera/camera_info (sensor_msgs/msg/CameraInfo) - Camera calibration info (not working yet)

Visualization Topics

• /table_mesh (visualization_msgs/msg/Marker) - Table mesh to display the table in rviz

TODO

The following features and improvements are planned for future development:

• Physics tuning: When stopping the robot, it continues to move a bit due to momentum, but the Gazebo controller doesn't register this movement properly
• World file enhancement: Add a world file with the table geometry to simulate physical walls for collision detection
• Opponent robot behavior: Add a small node to make the opponent robot move randomly for more realistic simulation scenarios