Hierarchical Plan Repair via Plan Recognition and Plan Correction

Hierarchical planning extends classical planning by introducing a hierarchy of tasks describing how tasks decompose into subtasks until primitive tasks -- actions -- forming a plan are obtained. Plan repair deals with plans that failed to execute due to a sudden state change. In particular, plan repair modifies the not-yet executed suffix of the plan to achieve the original goal. Hierarchical plan repair aims to modify a partially executed plan while respecting the task hierarchy. This paper describes how hierarchical plan repair can be realized by solving closely related hierarchical plan recognition and correction problems.