Learn ROS-ROS2 with Real Code Examples

ROS uses a node-based architecture where each node performs a specific task, communicating via topics, services, and actions.

ROS2 improves on ROS1 by adding real-time capabilities, DDS-based communication, and better security and multi-robot support.

Both ROS and ROS2 abstract hardware through device drivers and hardware interfaces, allowing platform-independent programming.

Supports simulation, visualization, and testing through tools like Gazebo, RViz, and rqt.

Widely used in academic research, industrial robotics, autonomous vehicles, and robotic middleware development.

Pub-sub messaging system for asynchronous communication

Service calls for synchronous operations

Action interfaces for long-running tasks

Parameter server and configuration management

Integration with Gazebo, RViz, and other visualization/simulation tools

Nodes - independent processes performing tasks

Topics - asynchronous message communication

Services - synchronous request/response calls

Actions - preemptable long-running tasks

Parameters - runtime configuration values

src/ - source code of nodes

msg/ - custom message definitions

srv/ - custom service definitions

launch/ - launch files for starting multiple nodes

CMakeLists.txt & package.xml - build configuration and dependencies

Create a workspace and packages

Write nodes in Python or C++

Define messages and services as needed

Build the package using `catkin_make` or `colcon build`

Run and test nodes individually and in combination

Beginner: Create a talker/listener node

Intermediate: Implement simple navigation or sensor processing

Advanced: Multi-robot coordination with ROS2 DDS

Expert: Real-time perception and control on embedded platforms

Architect: Design full-stack robotics middleware with ROS2

ROS1 vs ROS2: ROS2 adds real-time support, DDS communication, and security

ROS vs custom C++ robotics frameworks: ROS provides standard middleware and ecosystem

ROS2 vs microcontroller firmware: ROS2 handles high-level logic; low-level drivers run on embedded firmware

ROS2 vs proprietary robot SDKs: ROS2 is open-source, modular, and flexible

ROS2 vs MATLAB Robotics Toolbox: ROS2 is runtime, open-source middleware; MATLAB is simulation and prototyping

2007–2009 - ROS1 created at Stanford and Willow Garage

2010 - ROS1 community adoption begins

2014 - ROS2 development starts by Open Robotics

2017 - ROS2 Ardent release with improved QoS and security

2019 - ROS2 Dashing and Eloquent release with LTS support

2022 - ROS2 Humble release stabilizes multi-platform support

2025 - ROS2 widely adopted in industrial and autonomous systems

Node - independent process performing tasks

Topic - asynchronous message channel

Service - synchronous request-response

Action - long-running preemptable task

DDS - Data Distribution Service (ROS2 communication middleware)