Adaptive dynamic surface control of a class of uncertain nonlinear systems in pure-feedback form using fuzzy backstepping approach

This paper presents an adaptive fuzzy controller for the robust backstepping control of a class of uncertain nonlinear systems in pure-feedback form. The proposed approach incorporates the Nussbaum gain function (NGF) and the dynamic surface control (DSC) into the existing adaptive fuzzy control scheme. The major features of the proposed method are that: 1) the two problems, control directions and control singularity, are well solved by use of the NGF; 2) the problem of ldquoexplosion of complexityrdquo inherent to the existing backstepping methods is eliminated by introducing the DSC technique; 3) the proposed control scheme has the adaptive mechanism with fewer adaptive laws, which results in less computation time burden. The performance of the proposed approach is demonstrated through a simulation example.