A Chattering Free Sliding Mode Observer with Application to DC Motor Speed Control

The main drawback of the classical sliding mode observer is the chattering problem which eliminated in the present via replacing the signum function with an approximation to get approximate classical sliding mode observer. When the signum function is replaced with an approximating one, the estimation error will not go to zero anymore, but it will go to the bounded region around the origin. In this paper, the bounded region is obtained and controlled by adjusting the parameters of the proposed observer. The DC motor system suffers from a perturbation vector, and unmeasured angular acceleration is utilized as an application to a nonlinear controller based on the proposed observer.