Fuzzy approximate disturbance decoupling of MIMO nonlinear systems by backstepping approach

The concept of fuzzy approximate disturbance decoupling is introduced for a class of MIMO nonlinear systems with unknown nonlinearities. Based on the backstepping technique, a direct adaptive fuzzy almost disturbance decoupling control scheme is proposed. The proposed fuzzy controllers guarantee internal uniform ultimate boundedness of the closed-loop adaptive systems and render a bounded approximate L2 gain from the disturbance input to the output. The main characteristics of the proposed algorithm is that the adaptive fuzzy controllers have a simple structure, and less adaptive parameters than the existing results. At last, the developed design scheme is applied to control a two continuous stirred tank reactor process. The simulation results illustrate the effectiveness of the method proposed in this paper. © 2007 Elsevier B.V. All rights reserved.