Fuzzy adaptive sliding-mode control for a class of nonlinear systems

A direct and an indirect adaptive fuzzy state feedback approximation are considered for a class of nonlinear systems. In this work the control system consists of sliding- mode control and an adaptive fuzzy logic control. An adaptive fuzzy approximation plays a dominant role to maintain the closed- loop stability. The sliding- mode control is inserted to handle the influence of external disturbance and fuzzy approximation error instead of upper bound of the plant. In this work a stable direct and an indirect fuzzy adaptive sliding-mode controller for a class of nonlinear system are developed. The developed algorithms guarantee the asymptotic stability of the closed-loop system. Two simulation examples are given to illustrate the performance of the proposed methods. Computer simulation results confirm that effect of both external disturbance and fuzzy approximation error can be compensated by the developed methods. A comparative study is also conducted for both algorithms.