my_bot

A differential drive mobile robot built with ROS 2 Jazzy and simulated in Gazebo Harmonic. The robot features a 2D lidar (RPLidar), two drive wheels with a caster wheel, and supports keyboard teleoperation.

Features

• Differential Drive — Two-wheeled robot with caster wheel, controlled via cmd_vel twist messages
• 2D Lidar — 360-degree laser scanner (simulated as GPU lidar in Gazebo, RPLidar A1/A2 on hardware)
• Gazebo Harmonic Simulation — Full physics simulation with sensor plugins, diff-drive control, and joint state publishing
• RViz2 Visualization — Real-time robot model and sensor data visualization
• Keyboard Teleoperation — Drive the robot using teleop_twist_keyboard
• ROS 2 / Gazebo Bridge — Clock, odometry, transforms, joint states, and laser scan all bridged between Gazebo and ROS 2

Project Structure

my_bot/
├── config/                  # RViz config and parameter files
├── description/             # Robot URDF/Xacro model files
│   ├── robot.urdf.xacro     # Main robot description (includes all xacro files)
│   ├── robot_core.xacro     # Chassis, wheels, caster, materials
│   ├── lidar.xacro          # Lidar sensor link, joint, and Gazebo plugin
│   ├── gazebo_control.xacro # Diff-drive and joint state publisher plugins
│   └── inertial_macros.xacro# Inertia calculation macros
├── launch/
│   ├── launch_sim.launch.py # Launch simulation (Gazebo + RViz + bridges)
│   ├── rsp.launch.py        # Robot state publisher
│   └── rplidar.launch.py    # Physical RPLidar hardware launch
├── worlds/                  # Gazebo world files
├── CMakeLists.txt
└── package.xml

Dependencies

• ROS 2 Jazzy
• Gazebo Harmonic
• ros_gz_sim, ros_gz_bridge
• robot_state_publisher, xacro
• teleop_twist_keyboard (for keyboard control)
• rplidar_ros (for physical lidar only)

Build

cd ~/Robot_simulation
colcon build --symlink-install
source install/setup.bash

Usage

Launch Simulation (Gazebo + RViz)

ros2 launch my_bot launch_sim.launch.py

Keyboard Control

In a separate terminal:

ros2 run teleop_twist_keyboard teleop_twist_keyboard

Launch Physical RPLidar

ros2 launch my_bot rplidar.launch.py
# Or specify the serial port:
ros2 launch my_bot rplidar.launch.py serial_port:=/dev/ttyUSB0

Robot Specs

Parameter	Value
Chassis	0.3 x 0.3 x 0.15 m
Wheel Radius	0.05 m
Wheel Separation	0.35 m
Caster Wheel Radius	0.05 m
Lidar Range	0.3 – 12 m, 360 samples
Max Linear Velocity	0.5 m/s
Max Angular Velocity	1.0 rad/s

License

MIT License — see LICENSE.md