Fuzzy direct adaptive control for a class of nonlinear systems

A direct adaptive tracking control architecture is proposed for a class of continuous-time nonlinear dynamic systems, for which an explicit linear par ameterization of the uncertainty in the dynamics is either unknown or impos sible. The architecture employs fuzzy systems to approximate the optimal co ntroller which is designed on the assumption that all the dynamics in the s ystem are known, develops fuzzy sliding controller to compensate for the pl ant uncertainties, smooth the control signals and increase robustness. Glob al asymptotic stability is established in the Lyapunov sense, with the trac king errors converging to a neighborhood of zero. The simulation results ve rify the effectiveness of the proposed control algorithm. (C) 1999 Elsevier Science B.V. All rights reserved.