• Below is an example of how tasks can be composed for Robotic Behavior
• It shows how tasks and skills can be composed flexibly
• Several tasks can be composed to be executed in sequence or in parallel (horizontal composition)
• A task can be refined with other tasks (vertical composition): Abstract tasks are refined to more concrete tasks.
• Refinement of tasks may be static or dynamic
  • Static: The tasks and eventually the order is known. E.g. making coffee always involves approaching the machine, putting a cup into the machine, pressing the button, etc.
  • Dynamic: The tasks and the order are not known in advance (i.e. to be solved by symbolic planning): E.g. it is not known what is the best way to clean up the table after customers left (what order, what to stack into each other, what to carry at once/first/next/last, etc.)
• Skills will finally translate to configurations of one or more components (lower right). E.g. moving the manipulator requires to configure the component for collision-free manipulation-planning in a certain environment and the manipulator component to move along these collission-free trajectories.
• Grasp cup relies on the existence of a task “recognize-object” which is later bound to “recognize-cup”.
• There are constraints that have to be maintained during the execution of a task, for example: the robot is not moving while manipulating.
• There are results of a task that effect execution of other tasks, even after the current task was finished. For example, grasping a cup means that the cup still is in the gripper after the execution is done.

• Architectural Pattern for Task-Plot Coordination (Robotic Behaviors)
• Architectural Pattern for Component Coordination
• Robotic Behavior Metamodel

This document contains material from:

• Lotz2018 Alex Lotz, "Managing Non-Functional Communication Aspects in the Entire Life-Cycle of a Component-Based Robotic Software System", Dissertation, Technische Universität München, München 2018.
• Lutz2017 Matthias Lutz, “Model-Driven Behavior Development for Service Robotic Systems: Bridging the Gap between Software- and Behavior-Models,” 2017. (unpublished work)
• Stampfer2018 Dennis Stampfer, "Contributions to System Composition using a System Design Process driven by Service Definitions for Service Robotics". Dissertation, Technische Universität München, München, Germany, 2018.