Disturbance attenuation-based sliding mode control with disturbance observer for mismatched uncertain system

A disturbance attenuation-based sliding mode control approach with an extended disturbance observer is proposed for systems with mismatched uncertainties. A novel adaptive sliding surface consisting of the disturbance estimation is presented to eliminate the effect of mismatched disturbance in the sliding mode. The proposed method exhibits the following two attractive features. First, the asymptotical stability of adaptive sliding mode can be guaranteed even if the disturbance estimation error of the disturbance observer exists. Second, the nominal performance of the proposed approach is close to that of the traditional sliding mode control method in the absence of uncertainties. Finally, simulation results of the numerical and application examples show that the proposed nonlinear sliding mode control approach has the better dynamic performance as well as robustness and chattering reduction compared with other nonlinear sliding mode control methods.