Here - Agents Lab - University of Nottingham

[10], distributed middleware [11], and autonomic computing [12]. These works,however, do not address the same type of problem considered here: functional coordinationof a robotic ecology, in which the components of the system exchangecontinuous streams of data and can interact with the physical world.Although classical AI planning such as STRIPS based operators can easilybe extended to take the role of high-level coordinators for robotic ecologies [13][14], these planning methods suffer from a number of challenges that make themless than ideal.The first of these challenges is due to the demands on robustness combinedwith a demand of combinatorial generality where the possible combinationsof devices should be able to provide functionalities to assist other devices isexpected to grow superlinearly as more devices are added to the ecology. Computingwhich actions are to be performed by individual devices are traditionallydelegated to an action planner that reasons about the possible outcomes of differentactions on a given model of the environment. As the environments becomeincreasingly complex, unstructured and with increasing demands of methods foraccurately handling errors in perception or actuation these planning models tendto increase in complexity and to become intractable.Fig. 1. A simple PEIS-Ecology (taken from [6]). Left: The ceiling cameras provideglobal positioning to the robot. The robot performs the door opening action by askingthe refrigerator to do it. Right: Corresponding functional configuration of the devicesinvolvedWe call the set of devices that are actively exchanging data in a collaborativefashion at any given time the configuration of the ecology. The task of computingthe configuration to be used at any given time in order to accomplish the actionsgenerated by an action planner can also be modelled explicitly as a search problemand solved either in a dedicated configuration planner or as an integral stepof the action planners. For this purpose such configuration planners typicallyrely on introspection and semantic descriptions of the available components inorder to create a domain description that includes all the available devices andthe actions and data-exchange functionalities that they support. This is illustratedFigure 2 where a configurator plans for a subset of the available devices toperform specific localization tasks in order to assist the robot Astrid to navigateand open a refrigerator door.72