Constraint-Based Controller Synthesis in Non-Deterministic and Partially Observable Domains

Controller synthesis consists in automatically building controllers taking as inputs observation data and returning outputs guaranteeing that the controlled system satisfies some desired properties. In system specification, these properties may be safety properties specifying that some conditions must always hold. In planning, they express that the evolution of the controlled system must terminate in a goal state. In this paper, we propose a generic approach able to synthesize memoryless or finite-memory controllers for both safety-oriented and goal-oriented control problems. This approach relaxes some restrictive assumptions made by existing work on controller synthesis with non-determinism and partial observability and is shown to induce potentially significant gains. The proposed "Simulate and Branch" algorithm consists in exploring the possible evolutions of the controlled system and in adding new control elements when uncovered states are discovered. The approach developed is constraint-based in the sense that control problems are formulated using the flexibility of constraint programming languages and that our implementation uses the Gecode constraint programming library.