Robust backstepping control of a class of nonlinear systems using fuzzy logic

Fuzzy Logic (FL) controllers for the robust back stepping control of a class of nonlinear systems in both continuous and discrete-time are presented. Control action is employed to achieve tracking performance for unknown nonlinear system. Novel parameter tuning algorithms are obtained that are similar to E-modification in the case of continuous-time adaptive control. Uniform ultimate boundedness of the tracking error and the fuzzy parameter estimates are presented without using the persistency of excitation (PE) condition. Initialization of the fuzzy parameters is straightforward. Simulation results justify the theoretical conclusions. (C) 2000 Published by Elsevier Science Inc. All rights reserved.