Pure Coordination Using the Coordinator-Configurator Pattern
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This document presents the Coordinator-Configurator pattern for pure coordination in component-based robotic systems. The pattern splits the traditional "rich" coordinator into a pure coordinator and a configurator. The coordinator communicates with the configurator only through events, while the configurator applies configurations to execute actions. This separation improves reusability, determinism, and robustness compared to traditional approaches. The document also describes how domain-specific languages can be used to define configurations and discusses how deployment can be viewed as a form of runtime coordination.
![Coordination Statechart (subset)
unsynchronized and coupling coordination
synchronized model
unsynchronized
whether the communication
quality is sufficient or not.
e_QoS_OK e_QoS_NOTOK
Switch between
gravity comp and copying synchronized
depending on the current forces.
gravity_comp
Impedance control and gravity
[ above_force_thres() ]
compensation are enabled upon [ ! above_force_thres() ]
entering and exiting copying copying
respectively. entry: enable_copying(true)
exit: disable_copying(false)
National Institute of
Advanced Industrial Science
and Technology
Pure Coordination using the Coordinator–Configurator Pattern
AIST](https://image.slidesharecdn.com/3-purecoordinationusingthecoordinator-configuratorpattern-121120145626-phpapp01/85/Pure-Coordination-Using-the-Coordinator-Configurator-Pattern-8-320.jpg)
Pure Coordination Using the Coordinator-Configurator Pattern
- 1. Pure Coordination using the Coordinator–Configurator Pattern 3rd International Workshop on Domain-Specific Languages and models for ROBotic systems M. Klotzbuecher1 Geoffrey Biggs2 Herman Bruyninckx1 1 Department of Mechanical Engineering Katholieke Universiteit Leuven Belgium 2 Intelligent Systems Research Institute AIST, Japan. November 5, 2012 National Institute of Advanced Industrial Science and Technology Pure Coordination using the Coordinator–Configurator Pattern AIST
- 2. Introduction Context: coordination in component based systems. Coordination supervises and monitors functional computations. Commonly used coordination models: FSM, Petri-nets, Statecharts, SFCs. Common practice: in a Coordination FSM: Call methods/operations (move to) Change parameters (e.g. set a gain) Start and stop components ... National Institute of Advanced Industrial Science and Technology Pure Coordination using the Coordinator–Configurator Pattern AIST
- 3. Problem Statement The common practice of tightly integrating the action execution within the Coordinator has three disadvantages: 1 Reduced resuability of Coordinator due to pollution with platform dependent information. 2 Reduced determinism of Coordinator Logical (no separation between logical and platform specific error). Temporal (due to blocking calls). ... 3 Reduced robustness of Coordinator: crashing or indefinite blocking of calls will render Coordinator inoperative. National Institute of Advanced Industrial Science and Technology Pure Coordination using the Coordinator–Configurator Pattern AIST
- 4. Approach: Coordinator-Configurator Pattern Split “rich” coordinator into Coordinator Pure Coordinator and Configurator. command events status events Coordinator commands and Configurator call monitors via events only. start/stop Configurator is configured with computation configure a set of Configurations that it applies upon receiving the computation respective event. computation Success or failure is likewise reported via events. National Institute of Advanced Industrial Science and Technology Pure Coordination using the Coordinator–Configurator Pattern AIST
- 5. The Role of the DSL Formalization: A language to express the Configurator–Configuration; Shields Coordinator from: Software platform specific details (e.g. how to change a property) Hardware platform specific details (e.g. how a specific gripper is opened) Encourages construction of reusable Coordinators by introducing: A dedicated language to model change The Configurator as a dedicated entity to apply change The approach is independent of the specific coordination model used. National Institute of Advanced Industrial Science and Technology Pure Coordination using the Coordinator–Configurator Pattern AIST
- 6. Case study: dual youbot coupling Two KuKA YouBots coupled using impedance control. Safe behavior: switch to gravity compensation upon exceeding a force threshold or communication breakdown. National Institute of Advanced Industrial Science and Technology Pure Coordination using the Coordinator–Configurator Pattern AIST
- 7. Component structure youbot_coupling Coordinator command events status events Configurator e_force_thres_exceeded/below computation connected to CartPosMsr CartPosDsr of peer Youbot Cart_Impedance CartForceDes CartPosMsr Connected to CartPosDsr of peer Youbot Dynamics eQoS_change heartbeat_in youbot_driver commlat heartbeat_out National Institute of Advanced Industrial Science and Technology Pure Coordination using the Coordinator–Configurator Pattern AIST
- 8. Coordination Statechart (subset) unsynchronized and coupling coordination synchronized model unsynchronized whether the communication quality is sufficient or not. e_QoS_OK e_QoS_NOTOK Switch between gravity comp and copying synchronized depending on the current forces. gravity_comp Impedance control and gravity [ above_force_thres() ] compensation are enabled upon [ ! above_force_thres() ] entering and exiting copying copying respectively. entry: enable_copying(true) exit: disable_copying(false) National Institute of Advanced Industrial Science and Technology Pure Coordination using the Coordinator–Configurator Pattern AIST
- 9. The DSL implementation: Configurator–Configuration Configuration { disable_copying = Configuration{ port_write("Cart_Impedance.ext_ref_mode", false) }, enable_copying = Configuration { port_write("Cart_Impedance.ext_ref_mode", true) }, eight_DOF = Configuration { property_set("Dynamics.force_gain", {0.1, 0.1, 0.1}) }, five_DOF = Configuration { property_set("Dynamics.force_gain", {0, 0, 0}) }, National Institute of } Advanced Industrial Science and Technology Pure Coordination using the Coordinator–Configurator Pattern AIST
- 10. Side node: Unifying Deployment and Coordination Observation: By extending the Configurator with primitives for instantiating components, create_components deployment and startup can be naturally e_create_components_OK expressed as just another case of runtime Coordination. configure_components e_configure_components_OK start_components National Institute of Advanced Industrial Science and Technology Pure Coordination using the Coordinator–Configurator Pattern AIST
- 11. Conclusions The coordinator-configurator pattern enables: Reusability, by encapsulating software and hardware platform specifics in the Configurator–Configuration. Increased determinism, by separating commanding and execution. Higher robustness of the Coordinator, by shielding it from the execution of actions. Deployment is reduced to just an other case of run-time coordination. National Institute of Advanced Industrial Science and Technology Pure Coordination using the Coordinator–Configurator Pattern AIST
- 12. Thanks Questions? Acknowledgements This research was funded by the European Community under grant agreements FP7-ICT-231940 (Best Practice in Robotics), and FP7-ICT-230902(ROSETTA), and by K.U.Leuven’s Concerted Research Action Global real-time optimal control of autonomous robots and mechatronic systems. National Institute of Advanced Industrial Science and Technology Pure Coordination using the Coordinator–Configurator Pattern AIST