Frequency Response Analysis of Linear Active Disturbance Rejection Control

In this paper, the design of linear active disturbance rejection control (LADRC) for high order systems is presented and the frequency response is analyzed. First, the LADRC for minimum-phase processes is introduced, and the parameterization of tuning paramters, which reduces the tuning parameters to controller bandwidth and observer bandwidth, is given. With the transfer function of the LADRC, the closed-loop transfer function, disturbance channel as well as sensitivity transfer function are derived, followed by the frequency response analysis. An illustrative example for an eighth order process is given to demonstrate the effectiveness of LADRC