Variable-structure-based fuzzy-logic identification of a class of nonlinear systems

A novel approach for identification of a class of nonlinear systems is introduced. It implements a variable-structure based fuzzy-logic identifier (VSFI) model. The proposed approach adopts a serial-parallel structure and, unlike most fuzzy identifiers, does not require measurements of all the system´s states. Based on output measurements, the system states are estimated using a recently developed scheme of a high-gain observer. It is shown that the proposed VSFI is stable provided that the system identified is stable. Furthermore, it can be shown that the estimator state-errors tend exponentially to an arbitrarily small ball of convergence. Simulation results illustrate that the identification scheme proposed might serve as a potential candidate for nonlinear system identification.