Finite State Controllers (FSCs) are an effective way/nto represent sequential plans compactly. By imposing/nappropriate conditions on transitions, FSCs/ncan also represent generalized plans that solve a/nrange of planning problems from a given domain./nIn this paper we introduce the concept of hierarchical/nFSCs for planning by allowing controllers/nto call other controllers. We show that hierarchical/nFSCs can represent generalized plans more compactly/nthan individual FSCs. Moreover, our call/nmechanism makes it possible to generate hierarchical/nFSCs in a modular fashion, or even to apply/nrecursion. We also introduce a compilation that/nenables a classical planner to generate hierarchical/nFSCs that solve challenging generalized planning/nproblems. The compilation takes as input a set of/nplanning problems from a given domain and outputs/na single classical planning problem, whose solution/ncorresponds to a hierarchical FSC.

This work is partially supported by grant TIN2015-67959 and the/nMaria de Maeztu Units of Excellence Programme MDM-2015-/n0502, MEC, Spain. Sergio Jimenez is partially supported by the /nJuan de la Cierva program funded by the Spanish government.