A BLDCM servo system using a variable structure controller with an adaptive switching slope

This paper presents a study of a brushless DC motor (BLDCM) servo system using a variable structure controller (VSC). This method keeps a small slope of switching surface at the early control stage and gradually increases it as the tracking error decreases when the system approaches the steady state. In such a way, the method enhances the inherent robustness of the VSC system by reducing its sensitivity to disturbances as the duration of the reaching phase is reduced. Results from simulations on the BLDCM servo system are included to illustrate the effectiveness of the proposed method