Reachability analysis of complex planar hybrid systems

• We transform two-dimensional non-linear control systems to a class of hybrid systems.
• We present a sound, complete, terminating transformation algorithm.
• We give a sound, complete, terminating over-approximation reachability algorithm.
• An implementation of the theoretical results is introduced with case studies.

Hybrid systems are systems that exhibit both discrete and continuous behavior. Reachability, the question of whether a system in one state can reach some other state, is undecidable for hybrid systems in general. In this paper we are concerned with GSPDIs, 2-dimensional systems generalizing SPDIs (planar hybrid systems based on “simple polygonal differential inclusions”), for which reachability have been shown to be decidable. GSPDIs are useful to approximate 2-dimensional control systems, allowing the verification of safety properties of such systems.In this paper we present the following two contributions: (i) an optimized algorithm that answers reachability questions for GSPDIs, where all cycles in the reachability graph are accelerated. (ii) An algorithm by which more complex planar hybrid automata are over-approximated by GSPDIs subject to two measures of precision. We prove soundness, completeness, and termination of both algorithms, and discuss their implementation.