(16) COPLAS, a Conditional Planner with Sensing Actions

Title of the Research Project, Principal Investigator

(1) Title of the Research Project

COPLAS, a Conditional Planner with Sensing Actions

(2) Principal Investigator

Dr. Jorge LOBO, Associate Professor,
University of Illinois at Chicago

Contents

In this project we are developing a domain independent, logic programming-based planner for domain descriptions that include: sensing actions, actions with non-deterministic effects and actions with conditional effects. The domain description language is a simplified version of the language Ak presented at AAAI97. The major modifications of the language has been in its semantics. The original semantics was based on structures similar to Kripke models in order to capture knowledge (required for sensing actions). We have developed a new semantics based on sets of pairs of sets representing the true and false statements that the planner will know about the world. This limits the the disjunctive reasoning of the planner but greatly improves its performance.

In our original proposal we planned to use the system CORAL to write our implementation. However, during the development of the system we have found that the developers of CORAL have decided to stop its support. Thus, for portability reasons, we have decided to finish our implementation in SICSTUS prolog. We will continue a parallel implementation of the system in CORAL but our final deliverable will be in Prolog.

In the proposal we restricted the sensing actions to have no conditions. The current design will be able to handle conditions as long as all the propositions associated with a sensing action share the same preconditions. Our plan is to have completed the planner (with no while-loops) by the end January. We will prepare the report plus a small collection of examples to accompany the software during February.