ROS2 Actions — Complete Guide for Robotics
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ROS2 actions handle long-running, cancellable tasks like navigation or arm trajectory execution — with progress feedback during the goal.
The concept concept: ROS2 actions handle long-running, cancellable tasks like navigation
Difficulty 3/5 · ClassroomA ROS2 action is a goal-oriented communication pattern for long-running tasks. A client sends a goal, the server accepts it, sends periodic feedback, and finally returns a result. The client can cancel at any time.
💡 Think of it like…
Think of it like a household object that does the same job — the underlying idea is the same, just adapted for robots.
Why it matters
Without ros2 actions — complete guide for robotics, many concept systems in robotics simply couldn't work.
ROS2 Actions
What is it?
A ROS2 action is a goal-oriented communication pattern for long-running tasks. A client sends a goal, the server accepts it, sends periodic feedback, and finally returns a result. The client can cancel at any time.
How it works
An action has three sub-types: goal, feedback, and result. Under the hood, an action is built from several services and a topic — but rclcpp_action and rclpy_action give you a clean API. Common actions are NavigateToPose (move base) and FollowJointTrajectory (arm motion).
Real-world example
Nav2 uses NavigateToPose as its action. MoveIt2 uses FollowJointTrajectory for arm planning. A delivery robot might expose Deliver(parcel_id) as a custom action with feedback like 'percent complete'.
Why it matters for robotics
Actions are essential whenever a task is long, cancellable, or needs progress reporting. Building well-designed actions is the mark of a senior ROS2 engineer.
See also
Ask R2 Co-pilot anything you didn't understand about ROS2 Actions — Complete Guide for Robotics. It'll explain it plainly.
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Last updated · 2026-05-21
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