Adaptive sliding mode control with nonlinear disturbance observer for uncertain nonlinear system based on backstepping method

A chattering reduction sliding mode control (SMC) via backstepping scheme is proposed for a class of mismatched uncertain nonlinear systems. The most significant property of SMC system is its robustness, but SMC has some difficulties to handling mismatched uncertainties. Backstepping method doesn't need matching conditions. The method of combination of SMC and backstepping become effective in solving the mismatched uncertainties. The robust of the systems is guaranteed. But chattering caused by using SMC is not good for system. A nonlinear disturbance observer is used to estimate disturbance. Whole disturbance of the closed-loop systems is reduced. The chattering of sliding controller is reduced clearly. The proposed method is validated by simulation.