Monitoring the Execution of Plans in SIPE (System for Interactive Planning and Execution Monitoring).

摘要

In real-world domains (a mobile robot is used as a motivating example), things do not always proceed as planned. Therefore it is important to develop better execution-monitoring techniques and replanning capabilities. This paper describes the execution-monitoring and replanning capabilities of the SIPE planning system. (SIPE assumes that new information to the execution monitor is in the form of predicates, thus avoiding the difficult problem of how to generate these predicates from information provided by sensors.) The execution-monitoring module takes advantage of the rich structure of SIPE plans (including a description of the plan rationale), and is intimately connected with the planner, which can be called as a subroutine. The major advantages of embedding the replanner within the planning system itself area: (1) The replanning module can take advantage of the efficient frame reasoning mechanisms in SIPE to quickly discover problems and potential fixes; (2) The deductive capabilities of SIPE are used to provide a reasonable solution to the truth maintenance problem; and (3) The planner can be called as a subroutine to solve problems after the replanning module has inserted new goals in the plan. Another important contribution is the development of a general set of replanning actions that will form the basis for a language capable of specifying error-recovery operators, and a general replanning capability that has been implemented using these actions. (Author).