ROS2

ROS2 is the successor to [[ros]]. Where ROS1 had a single master node and a custom transport, ROS2 is built on DDS (Data Distribution Service) — an industrial-grade pub/sub middleware used in aerospace and defence for two decades. No master, real-time support, security built in, and multi-robot is native.

The four communication patterns

• Topics — pub/sub. Sensor data, continuous streams. /scan, /cmd_vel.
• Services — request/response. Short queries.
• Actions — long-running goals with feedback and cancellation. Nav2 uses these heavily.
• Parameters — per-node configuration values that can be read and set at runtime.

What makes it different from ROS1

Lifecycle nodes

A ROS2 lifecycle node has explicit states: unconfigured → inactive → active → inactive → finalized. You can configure() and cleanup() cleanly. Critical for safety-critical robots — your motor controller comes up only after sensors are validated.

In India

[[ISRO]]'s robotic-servicing prototypes run ROS2 for lifecycle guarantees. Ideaforge uses it on drones because DDS handles flaky wireless. GreyOrange, Ati Motors, Asimov Robotics, and Systemantics all build their products on ROS2 Humble or Iron. Indian university robotics programmes (IIT Madras, IIT Bombay, IIIT-H, BITS Pilani) have switched curricula from ROS1 to ROS2.

See it in action

A minimal ROS2 publisher in Python — the entire stack discovers, connects, and starts streaming with no config:

import rclpy
from rclpy.node import Node
from std_msgs.msg import String

class Talker(Node):
    def __init__(self):
        super().__init__('talker')
        self.pub = self.create_publisher(String, '/chatter', 10)
        self.create_timer(1.0, lambda: self.pub.publish(String(data='hello')))

rclpy.init()
rclpy.spin(Talker())

Open a second terminal: ros2 topic echo /chatter. Messages appear. No master, no config, no glue.

Related concepts

[[ros]] · [[lidar]] · [[slam]] · [[computer-vision]] · [[edge-computing]]

Start the Wire track to learn ROS2 hands-on.