A Relay Feedback Method for the Tuning of Linear Active Disturbance Rejection Controllers

Wenqing Cui,Wen Tan,Donghai Li,Yutong Wang,Shuqing Wang

doi:10.1109/access.2019.2963419

Abstract

Active disturbance rejection control (ADRC) is a new control method that estimates the total disturbance by an extended state observer and compensates it by a state feedback law, and good disturbance rejection performance is expected compared to traditional PID control method. However, the parameters of ADRC are hard to tune, even for linear ADRC (LADRC). This paper proposes a new tuning method for second-order LADRC based on relay feedback, which is simple to implement without knowing the information of the controlled plant. Simulation examples show that the proposed method can achieve good performance in disturbance rejection and robust performance. The tuning rule is also tested for the control of a steam condenser. Compared with PID, the proposed method has smaller overshoot and shorter settling time.

Highlights

Tuning of controllers for plants with uncertainties are important and challenging for control systems design
The rest of the paper is arranged as follows: The basic theory of second-order linear ADRC (LADRC) and relay feedback is introduced in Section 2; Section 3 reviews [23] briefly and the tuning formula is derived; In Section 4, some benchmark systems are used to verify the applicability of the proposed method; In Section 5, the tuning formula is applied to a close-to-real steam condenser
CLOSE-TO-REAL SIMULATION To further verify the effectiveness of the proposed method, we will use a steam condenser model to illustrate the advantage of relay-tuning method which can obtain the initial value of parameters of LADRC quickly without knowing the information of plant

Summary

INTRODUCTION

Tuning of controllers for plants with uncertainties are important and challenging for control systems design. A relay is used in the feedback loop connected to the process and after that the parameters of PID are obtained by Ziegler-Nichols tuning rules Luyben extended this method in [27], and showed that it is a good way to obtain plant information and to design controllers in process control by the method of relay feedback [28]–[31]. The rest of the paper is arranged as follows: The basic theory of second-order LADRC and relay feedback is introduced in Section 2; Section 3 reviews [23] briefly and the tuning formula is derived; In Section 4, some benchmark systems are used to verify the applicability of the proposed method; In Section 5, the tuning formula is applied to a close-to-real steam condenser.

BACKGROUND

RELAY FEEDBACK

SIMULATIONS

CONCLUSION