HOTRiDE: Hierarchical Ordered Task Replanning in Dynamic Environments

One of the assumptions in classical planning is that the environment is static: i.e., the planner is the only entity that can induce changes in the environment. A more realistic assumption is that the environment is dynamic; that is, there are other entities in the world and the actions generated by the planner may fail due to the operations of these entitites. In this paper, we describe a planning system, called HOTRiDE (Hierarchical Ordered Task Replanning in Dynamic Environments), which interleaves plan generation, execution, and repair in order to work under such circumstances. Our approach is an extension of SHOP (Simple Hierarchical Ordered Planner) (Nau et al. 1999), which is a well-known Hierarchical Task Network planning system. Our experiments with HOTRiDE in an abstracted version of a military-planning domain demonstrates the potential of our approach.