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Action

Action is the stage where the robot executes planned commands on physical systems.

At this point, abstract plans and trajectories are translated into real-world movements, such as motor control, steering, or actuator commands.

1. Motion Execution​

  • Goal: Execute movement based on planned trajectories

  • Input:

    • Path / trajectory
    • Velocity commands

  • Output:

    • Motor control signals
    • Wheel velocities

  • ROS 2 Topics Example:

    /cmd_vel

2. Control Systems​

  • Goal: Ensure accurate and stable execution of motion
  • Common Methods:
    • PID Control
    • Model Predictive Control (MPC)
    • Feedback control using sensor data
  • Examples:
    • Maintaining a straight path
    • Smooth acceleration and deceleration
    • Precise positioning

3. Hardware Interface​

  • Goal: Bridge software commands to physical hardware
  • Components:
    • Motor drivers
    • Robot base controllers
    • Robotic arm controllers
    • Drone flight controllers
  • ROS 2 Framework:
    • ros2_control → Standard interface for robot hardware
    • Hardware interface plugins

4. Practical Implementation (ROS 2)​

  • Action modules subscribe to planning outputs: 
    /cmd_vel
    /trajectory
  • And interact with hardware through: 
    /joint_states
    /odom
  • Common tools:
    • ros2_control → Hardware abstraction and control
    • RViz2 → Monitor robot state
    • rqt_graph → Verify control pipeline

Action brings the robot’s decisions into the real world through precise and controlled execution.

Pipeline Summary:

  • Sensing → Perception → Planning → Action