jarabot-simulator-slam

A ROS 2 Humble–based Jarabot simulator with Cartographer SLAM integration.

Author

Yonguk Cho
Robotics Developer / ROS 2 Engineer
Creator of Jarabot Simulator

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This repository extends the original Jarabot Simulator by adding Cartographer SLAM, enabling real-time map building and localization using simulated LiDAR data.

It is designed for ROS 2 SLAM education, simulation-based testing, and algorithm development without real hardware.

Keywords: ROS2 Simulator, Mobile Robot Simulator, LiDAR, RViz2, Odometry, TF, SLAM, Navigation2, Cartographer

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Image of the actual JaraBot

Image of the Jarabot simulator operating in RViz

Image of the Jarabot simulator operating in RViz with Cartographer

Features

• 2D differential-drive mobile robot simulator
• Simulated 2D LiDAR (/scan)
• Encoder-based odometry (/odom)
• TF tree broadcasting (odom → base_link)
• Cartographer SLAM integration
• RViz2 visualization
• Keyboard teleoperation
• Safety stop node for collision protection

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Requirements

• Ubuntu 22.04
• ROS 2 Humble
• RViz2

ros2 -h
echo $ROS_DISTRO   # should output: humble

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Workspace Structure

This repository follows the standard ROS 2 colcon workspace layout:

jarabot_sim_ws
├── src
│   ├── jarabot_sim
│   ├── jarabot_sim_cartographer
│   ├── jarabot_sim_interfaces
│   ├── jarabot.png
│   ├── jarabot_sim_rviz.png
│   └── README.md
├── build
├── install
└── log

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⚠️ build/, install/, and log/ directories are generated by colcon and are not required to be pushed to GitHub.

Packages Overview

1. jarabot_sim

• Core simulator package.
• LiDAR simulation
• Encoder & odometry
• TF publishing
• RViz marker & path visualization
• Safety stop node

2. jarabot_sim_cartographer

• Cartographer SLAM integration package.
• Cartographer configuration
• SLAM launch files
• Map generation in RViz

3. jarabot_sim_interfaces

Custom message definitions for Jarabot.

Required Tools

These are needed to build and manage ROS workspaces.

sudo apt update
sudo apt install -y \
  git \
  python3-colcon-common-extensions \
  python3-rosdep \
  build-essential

Required ROS 2 Packages (Simulator)

Required for simulation, TF handling, and RViz visualization.

sudo apt install -y \
  ros-humble-rviz2 \
  ros-humble-tf2-ros ros-humble-tf-transformations \
  ros-humble-robot-state-publisher \
  ros-humble-joint-state-publisher \
  ros-humble-nav-msgs \
  ros-humble-sensor-msgs \
  ros-humble-geometry-msgs \
  ros-humble-teleop-twist-keyboard

Cartographer SLAM (Required for Mapping)

Used to generate a 2D map from simulated LiDAR data.

sudo apt install -y \
  ros-humble-cartographer \
  ros-humble-cartographer-ros

Installation

mkdir -p ~/jarabot_sim_ws/src
cd ~/jarabot_sim_ws/src
git clone https://github.com/playros/jarabot-simulator-slam.git .

Build

cd ~/jarabot_sim_ws
colcon build
source install/setup.bash

Running the Simulator + SLAM

This project is designed to be run using 5 separate terminals.

Terminal 1 – Jarabot Simulator

source ~/jarabot_sim_ws/install/setup.bash
ros2 launch jarabot_sim jarabot_simulator.launch.py

Terminal 2 – Cartographer SLAM

source ~/jarabot_sim_ws/install/setup.bash
ros2 launch jarabot_sim_cartographer cartographer_slam.launch.py

Terminal 3 – RViz2

source ~/jarabot_sim_ws/install/setup.bash
rviz2

Terminal 4 – Keyboard Teleoperation

source ~/jarabot_sim_ws/install/setup.bash
ros2 run teleop_twist_keyboard teleop_twist_keyboard \
  --ros-args -r cmd_vel:=/cmd_vel_raw

Terminal 5 – Safety Stop Node

source ~/jarabot_sim_ws/install/setup.bash
ros2 run jarabot_sim jarabot_sim_safety_stop

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Post-Launch Checklist (Quick Verification)

Nodes are running

ros2 node list

Expected:

• jara_sim_* nodes (encoder, odometry, lidar, marker, path)
• cartographer_node
• cartographer_occupancy_grid_node

📌 If Cartographer nodes are missing, SLAM is not running.

Required topics exist

ros2 topic list | grep -E "/cmd_vel|/scan|/odom|/map|/tf"

Topic	Purpose
/cmd_vel	Robot velocity command
/scan	Simulated LiDAR
/odom	Odometry
/map	SLAM-generated map
/tf	Coordinate transforms

Topics are publishing data

ros2 topic hz /scan
ros2 topic hz /odom
ros2 topic hz /map

✔ If frequency is not zero, the system is working.

TF tree is connected (MOST IMPORTANT)

ros2 run tf2_ros tf2_echo map base_link

Expected TF chain:

map → odom → base_link

📌 If this is broken, the map will not appear correctly in RViz.

Robot movement test

ros2 topic pub --once /cmd_velros2 topic pub --once /cmd_vel_raw geometry_msgs/msg/Twist "{linear: {x: 0.2}, angular: {z: 0.0}}" geometry_msgs/msg/Twist \
"{linear: {x: 0.2}, angular: {z: 0.0}}"

• Robot moves
• Odometry changes
• Map updates in RViz

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Keyboard Control (teleop_twist_keyboard)

Key	Action
i	Move forward
,	Move backward
j	Rotate left
l	Rotate right
k	Stop
q / z	Increase / decrease speed
Ctrl + C	Exit

Main Topics

Topic	Type	Description
/scan	sensor_msgs/LaserScan	Simulated LiDAR
/odom	nav_msgs/Odometry	Odometry
/tf	TF	Coordinate transforms
/cmd_vel_raw	geometry_msgs/Twist	Raw velocity command
/map	nav_msgs/OccupancyGrid	SLAM-generated map

Visualization

RViz2 can be used to visualize:

• Robot model & markers
• LiDAR scan
• SLAM map
• Robot trajectory
• TF tree

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Use Cases

• ROS 2 SLAM education
• Cartographer configuration testing
• Navigation2 pre-integration testing
• Simulation-only robotics training

Summary

• This project provides a ROS 2 Humble–based 2D mobile robot simulator
• Includes virtual LiDAR, odometry, TF, and Cartographer SLAM
• Designed for education, SLAM testing, and algorithm development

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License

MIT License

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• Developed and maintained by Yonguk Cho
• Jarabot Simulator (also known as jarabot-simulator or jarabot simulator)