Identification of nonlinear systems having hard function

In this work, an identification approach of nonlinear systems is studied. Presently, the nonlinear system can be described by Wiener-Hammerstein model. This latter is composed of a nonlinearity surrounded by two linear blocks. The linear blocks can be nonparametric. The nonlinear element is allowed to be discontinuous, specifically it can be of hard element (e.g. Preload, Coulomb friction, Dead-zone). Roughly, it is very difficult to model these types of nonlinearities by orthogonal decompositions (e.g. polynomial).