Analysis and Design of Control System with Equivalent-Input-Disturbance Estimation

Abstract — This paper examines the mechanism of distur-bance rejection in control systems employing a technique called equivalent-input-disturbance estimation. Analysis of the mechanism shows that the filter in the control system strongly affects the disturbance rejection performance. A new method of designing such control systems that employs H ∞ control theory and linear matrix inequalities is presented; and simulations of a magnetic levitation system demonstrate its validity. I