  One way to analyze Cyber-Physical Systems is by modeling them as hybrid
automata. Since reachability analysis for hybrid nonlinear automata is a very
challenging and computationally expensive problem, in practice, engineers try
to solve the requirements falsification problem. In one method, the
falsification problem is solved by minimizing a robustness metric induced by
the requirements. This optimization problem is usually a non-convex non-smooth
problem that requires heuristic and analytical guidance to be solved. In this
paper, functional gradient descent for hybrid systems is utilized for locally
decreasing the robustness metric. The local descent method is combined with
Simulated Annealing as a global optimization method to search for unsafe
behaviors.
