TGA-Based Controllers for Flexible Plan Execution

Plans synthesized by Temporal Planning and Scheduling systems may be temporally flexible hence they identify an envelope of possible solutions. Such flexibility can be exploited by an executive systems for robust on-line execution. Recent works have addressed aspects of plan execution using a quite general approach grounded on formal modeling and formal methods. The present work extends such an approach by presenting the formal synthesis of a plan controller associated to a flexible temporal plan. In particular, the controller synthesis exploits Timed Game Automata (TGA) for formal modeling and UPPAAL-TIGA as a model checker. After presenting a formal extension, the paper introduces a detailed experimental analysis on a real-world case study that demonstrates the viability of the approach. In particular, it is shown how the controller synthesis overhead is compatible with the performance expected from a short-horizon planner.