Ella M. Atkins, Edmund H. Durfee, Kang G. Shin
The degree to which a planner succeeds and meets response deadlines depends on the correctness and completeness of its modelstwhich describe events and actions that change the world state. It is often unrealistic to expect perfect models, so a planner must detect and respond to states it had not planned to handle. In this paper, we characterize different classes of these "unhandled" states and describe planning algorithms to build tests for, and later respond to them. We have implemented these unhandled state detection and response algorithms in the Cooperative Intelligent Real-time Control Architecture (CIRCA), and present experiments from flight simulation that show how the new algorithm enables a fully-automated aircraft to react appropriately to certain classes of unhandled states, averting failure and giving the aircraft a new chance to achieve its goals.