  This paper examines the verification of stability, a control requirement,
over discrete control systems represented as Simulink diagrams, using different
model checking approaches and tools. Model checking comprises the (exhaustive)
exploration of a model of a system, to determine if a requirement is satisfied.
If that is not the case, examples of the requirement's violation within the
system's model are provided, as witnesses. These examples are potentially
complementary to previous work on automatic theorem proving, when a system is
not proven to be stable, but no proof of instability can be provided.
  We experimentally evaluated the suitability of four model checking approaches
to verify stability on a set of benchmarks including linear and nonlinear,
controlled and uncontrolled, discrete systems, via Lyapunov's second method or
Lyapunov's direct method. Our study included symbolic, bounded, statistical and
hybrid model checking, through the open-source tools NuSMV, UCLID, S-TaLiRo and
SpaceEx, respectively. Our experiments and results provide an insight on the
strengths and limitations of these model checking approaches for the
verification of control requirements for discrete systems at Simulink level. We
found that statistical model checking with S-TaLiRo is the most suitable option
to complement our previous work on automatic theorem proving.
