Robustness enhancement of DC drives with a smooth optimal sliding-mode control

A quantitative analysis of the robustness of a DC drive system under sliding-mode control is presented. Analytic solutions in the time domain of the drive transient speed deviation and its maximum value due to a step load application are obtained. The new design approach developed here for the third-order optimal sliding-mode control system effectively enhances the system robustness against external disturbance. The differences in design concept between the new robust design and the classical control approach are highlighted. The fast response speed and robust performance of the drive system are both achievable by the new design method without the necessity of compromise. Digital simulations verify the design and results. Practical system implementation based on a low-cost 16 bit CHMOS microcontroller are briefly addressed