  A piecewise constant Mayer cost function is used to model optimal control
problems in which the state space is partitioned into several regions, each
having its own Mayer cost value. In such a context, the standard numerical
methods used in optimal control theory naturally fail, due to the
discontinuities and the null gradients associated with the Mayer cost function.
In this paper an hybrid numerical method, based on both derivative-free
optimization and smooth optimization techniques, is proposed to solve this
class of problems. Numerical simulations are performed on some standard control
systems to show the efficiency of the hybrid method, where NOMAD and IPOPT are
used as, respectively, derivative-free optimization and smooth optimization
solvers.
