Formal Verification of abstract digital controllers for hybrid systems

This project proposes extensions of formal verification techniques, so as to bring finite state controllers of hybrid systems within the ambit of the verification framework. These controllers are represented using Kripke Structures whose states are labelled with Predicates Over Real Variables(PORVs). An extension to LTL is proposed, for representing the properties, and two model checking approaches one automata theoretic and the other symbolic are proposed for verifying such properties over PORV labelled Kripke Structures. The automata theoretic approach is based on the existing on-the-fly verification technique. Using SMT solvers, the symbolic approach reduces the verification problem into a usual model checking problem with propositions, which can be solved using industrial model checking tools. This project also addresses the problem of model checking under assume properties which may themselves contain PORVs. Correctness of the proposed model checking approaches are proven, and case studies are presented for illustrating the toolflow.