Planning and Acting While the Clock Ticks

Andrew Coles, Erez Karpas, Andrey Lavrinenko, Wheeler Ruml, Solomon Eyal Shimony, Shahaf S. Shperberg

Keywords: Temporal Planning, Execution, Real Time Search, Metareasoning

TL;DR: We propose a new problem, called concurrent planning and execution, in which actions can be dispatched (executed) before planning terminates, and propose an algorithm for solving it.

Abstract:

Standard temporal planning assumes that planning takes place offline, and then execution starts at time 0. Recently, situated temporal planning was introduced, where planning starts at time 0, and execution occurs after planning terminates. Situated temporal planning reflects a more realistic scenario where planning is online. However, in situated temporal planning a complete plan must be generated before any action is executed. In some problems with extreme time pressure, timing is too tight to complete planning before the first action must be executed. For example, an autonomous car which has a truck backing towards it should probably move out of the way now, and plan how to get to its destination later.
In this paper, we propose a new problem, called concurrent planning and execution, in which actions can be dispatched (executed) before planning terminates. Unlike previous settings, we must handle wall clock deadlines that affect action applicability and goal achievement (as in situated planning) while also supporting dispatching actions before a complete plan has been found. We extend previous work on metareasoning for situated temporal planning to develop an algorithm for this new setting. Our empirical evaluation shows that when there is extreme time pressure, our approach outperforms situated temporal planning.

Primary Keywords: Temporal Planning

Category: Long

Student: No

Submission Number: 9