How does the information chain looks like in the motor control

edit

Hello everybody,

i want to find out how ROS generates new motion control orders for example by dynamixel motors. How does the infromation chain looks like? In addition i put the overview picture for the navigation stack used in Turtlebot. Can anyone explain me how the base controller exactly works? i just get him velocity commands to interact with the local planner ![image description] ( http://wiki.ros.org/navigation/Tutori... )