Equivalence of nonlinear systems under dynamic state feedback

Nonlinear dynamic compensators are classified and the subclass of dynamic state feedback laws is identified. Dynamic state feedback is defined and some structural properties are established, like the fact that a dynamic compensator preserves the structure at infinity of the original system if, and only if, it is a dynamic state feedback. Dynamic equivalence, i.e., the problem of compensating a given nonlinear system by regular dynamic state feedback, so that its output exactly coincides with that of a second given system, is investigated. The notion of an interactor is introduced for general nonlinear systems and its relation to compensation by regular dynamic state feedback is established for input-output linearizable systems