Challenges in the Identification of Discrete Time Block Oriented Models for Continuous Time Nonlinear Systems

Abstract

Block oriented nonlinear models capture the dynamics of a nonlinear system with linear dynamic sub-systems (L), the nonlinear behavior is modeled using static nonlinear subblocks (N). In this paper we focus on three important theoretical and practical challenges that need to be addressed when the class of systems is generalized from the simple but very popular Wiener, Hammerstein, Hammerstein-Wiener or Wiener-Hammerstein systems to more complex nonlinear systems, including nonlinear feedback loops: 1) Dealing with complex blockoriented models: initial (structure revealing) tests; 2) Testing of candidate semi-physical blockoriented models; and 3) Approximating continuous time nonlinear systems by a discrete time recursive model. Experimental illustrations and verifications are shown.