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

Fuzzy Logic (FL) controllers for the robust back stepping control of a clas s of nonlinear systems in both continuous and discrete-time are presented. Control action is employed to achieve tracking performance for unknown nonl inear system. Novel parameter tuning algorithms are obtained that are simil ar to E-modification in the case of continuous-time adaptive control. Unifo rm ultimate boundedness of the tracking error and the fuzzy parameter estim ates are presented without using the persistency of excitation (PE) conditi on. Initialization of the fuzzy parameters is straightforward. Simulation r esults justify the theoretical conclusions. (C) 2000 Published by Elsevier Science Inc. All rights reserved.