Analyzing Failure Recovery to Improve Planner Design

Plans fail for many reasons. During planner development, failure can often be traced to actions of the planner itself. Failure recovery analysis is a procedure for analyzing execution traces of failure recovery to discover how the planner's actions may be causing failures. The four step procedure involves statistically analyzing execution data for dependencies between actions and failures, mapping those dependencies to plan structures, explaining how the structures might produce the observed dependencies, and recommending modi cations. The procedure is demonstrated by applying it to explain how a particular recovery action may lead to a particular failure in the Phoenix planner. The planner is modi ed based on the recommendations of the analysis, and the modifcations are shown to improve the planner's performance by removing a source of failure and so reducing the overall incidence of failure. This research was supported by DARPA-AFOSR contract F49620-89-C-00113, by the National Science Foundation under an Issues in Real-Time Computing grant, CDA-8922572, and by a grant from the Texas Instruments