Robust adaptive fuzzy dynamic surface control of uncertain nonlinear for systems

A robust adaptive fuzzy dynamic surface control design procedure is presented for a class of perturbed strict feedback nonlinear systems with both unknown virtual control coefficients and unknown nonlinearities via backstepping technique. The unknown nonlinearities comprise two types of nonlinear functions: one naturally satisfies the ldquotriangularity conditionrdquo and can be approximated by fuzzy logic systems, while the other is assumed to be partially known and consists of parametric uncertainties and known ldquobounding functionsrdquo, which of the influence is minified by using continuous robust. In this paper, by incorporating dynamic surface control technique into the fuzzy adaptive control design framework, the ldquoexplosion of complexityrdquo problem is avoided. By theoretical analysis, the closed loop signals uniformly ultimate boundedness is guaranteed, and the tracking error converges to a small neighbourhood around zero. At last, a simple simulation is included to illustrate the effectiveness of the proposed approach.