Frequency-domain characteristics analysis of linear active disturbance rejection control for second-order systems

Active Disturbance Rejection Control (ADRC) is a quiet different design concept that shows much promise in obtaining a consistent response in a control system with many uncertainties. For the lack of frequency-domain analysis, in this paper, starting from the frequency domain methods, the tracking ability of linear extended state observer (LESO) and the disturbance rejection quality of linear ADRC with the changing of the ADRC parameters are analyzed based on the closed-loop transfer function and frequency response. So the relationship between the system dynamics characteristics and the control parameters is obtained, contributing to the tuning parameters. Finally, the proposed method is applied to the strip tension control of Stainless Steel Strip Processing Line, in order to verify the effectiveness of this method.