🤖 DiffDriveRobot

🧭 Overview

DiffDriveRobot is the first open-source platform in the Project Gradus series,
implementing a fundamental two-wheel differential-drive structure.

▲ Figure 1. Front and side views of the DiffDriveRobot prototype

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🚀 Future Development

This section tracks the ongoing and upcoming development stages of DiffDriveRobot.
Each item will be updated with relevant commits and documentation as progress is made.

📁 Hardware & Design

• Upload full CAD and STL design files
• Complete commercial parts list under hardware/assembly/

⚙️ Control System

• Upload microcontroller code (ESP32 firmware)
• Upload ROS 2 bring-up code (communication nodes & launch files)

🧠 Simulation & Navigation

• Upload Gazebo simulation environment (URDF, world, and launch)
• Integrate Nav2 (Navigation2) stack for autonomous navigation
• Validate navigation stack with odometry and LiDAR data

🧩 Documentation

• Add wiring diagrams and connection guide in hardware/assembly/
• Add usage examples for real-world and simulation setups

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📁 Directory Description

Folder	Description
hardware/design/	Original CAD models and 3D-printable STL files
hardware/assembly/	Assembly guide, wiring diagrams, and commercial parts list
hardware/microcontroller/	ESP32 / micro-ROS firmware for motor control and encoder handling
hardware/bringup/	ROS 2 bring-up scripts and nodes for /cmd_vel ↔ /odom communication
simulation/	Gazebo setup for virtual testing
images/	Visual resources used in README or documentation
docs/	Technical notes, system diagrams, and development records

💡 The hardware/ directory unifies every step of real-world implementation — from design → assembly → microcontroller → ROS 2 bring-up — ensuring reproducibility and modular hardware development.

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⚙️ Key Features

• 🧩 ROS 2 Integration: Fully compatible with ROS 2 Humble and later

• 🧠 Odometry / Encoder Support: Real-time velocity and pose estimation

• 🎮 Velocity Control Interface: /cmd_vel topic for teleop and autonomous control

• 🪶 Lightweight 3D-Printed Chassis: Low-cost, easily modifiable body

  • The list of commercial off-the-shelf parts is available under Hardware → Assembly

• 🧱 Gazebo Simulation Environment: URDF + world files provided

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🧪 Simulation & Real-World Operation

🔹 Real-World Setup

ESP32 (MCU)

• Publishes /odom topic → encoder-based odometry data
• Subscribes to /cmd_vel → velocity commands from workstation

Laptop / Workstation

• Publishes /cmd_vel → drives the robot
• Subscribes to /odom → receives pose feedback for control and visualization

⚙️ Firmware under hardware/microcontroller/ handles the real-time control logic, while hardware/bringup/ contains the ROS 2 nodes and launch files used to operate the robot.

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🔹 Gazebo Simulation (Coming Soon)

Run the robot in Gazebo with:

ros2 launch diffdrive_robot simulation.launch.py

Keyboard teleoperation example:

ros2 run teleop_twist_keyboard teleop_twist_keyboard /cmd_vel:=/cmd_vel

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🛠️ Commercial Parts List

(to be detailed in hardware/assembly/)

Component	Model / Link	Description
BLDC Motor	TBD	3 N·m torque
Encoder	TBD	Wheel rotation feedback for odometry
Motor Driver	TB6612 / L298N	BLDC control
Battery	TBD	24 V · 20 Ah LiFePO₄ battery pack
Caster Wheel	TBD	Front and rear stabilizer wheels
LiDAR	Velodyne VLP-16	16-channel 3D LiDAR sensor for environment perception
Camera	Intel RealSense D435i	RGB-D camera for visual sensing
MCU	ESP32	Microcontroller
SBC	Jetson Orin NX	Single-board computer
IMU	TBD	--

🧩 This list is under continuous update.

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📜 License

This project follows an open-source philosophy. All resources are freely available for research and educational use. (Specific license details can be found in the LICENSE file.)

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