A frequency domain comparison of disturbance observer based control schemes

Abstract

In this article, an analysis and synthesis of widely used linear disturbance observer based robust control approaches are presented. The main objective of this article is to provide an exhaustive comparison of disturbance observer based robust control approaches and to handle the structural details of each approach for gaining insight about the complexity of each approach. Toward this goal, nine performances and robustness equations portraying useful insights for understanding and analyzing control systems are derived by examining their common and equivalent block diagrams. Four of them are selected as gang of four equations, namely complementary sensitivity function, sensitivity function, disturbance sensitivity function and noise sensitivity function. Robustness and disturbance rejection performance analysis of all linear disturbance observer based control schemes and classical feedback control scheme are done using gang of four equations. With these representations, two tables discussing all prime issues and facilitating the selection of the best approach are obtained. Our research stipulates critical facts and figures of each scheme by considering the derived gang of four equations, which can be used for choosing the most appropriate disturbance observer based control approach for a given robust control problem. It is concluded that the uncertainty disturbance estimator approach is superior when time delay type uncertainty is involved in the model. Unfolding this is critical as time delay is an inevitable fact in most industrial control systems. The findings also emphasize that time domain disturbance observer based control approach is proficient if there is no process time delay.

An Assessment of Active Disturbance Rejection Technique From a Theoretical Perspective

“…Some recent contributions on DOB techniques can be summarized as follows. A detailed survey is presented by Chen et al (Chen, Yang, Guo, & Li, 2016), wherein Bayrak and Efe compare the frequancy domain approaches of linear disturbance observer techniques (Bayrak & Efe, 2021). Furthermore, a nonlinear disturbance observer control shceme is proposed in (Efe & Kasnakoğlu, 2021), where the controlled plant has a discrete-time model.…”

Disturbance Observer-Based PID Control System Using DNA Strand Displacement and Its Application in Exponential Gate

“…Research on CRN-based control systems is currently primarily concerned with exploiting error signals to reduce the impact of outside disturbances, and controller design complexity is significant. In addition to being able to successfully suppress external disturbances, the disturbance observer-based control system(DOB) [29] also allows for the easy division of its overall control structure into two control loops. The outer loop controller is independently built to provide good setpoint tracking characteristics, while the compensation of the equivalent disturbance by the inner loop disturbance observer can enhance the disturbance suppression features of the system.…”

Attitude Autopilot Design Based on Fuzzy Linear Active Disturbance Rejection Control

“…To achieve the goal of stable control and improve the accuracy of disturbance rejection, disturbance observer-based control [24][25][26][27][28] has been widely proposed. Generally speaking, this kind of control method based on the disturbance observer can observe the disturbance on the one hand, and compensate for the disturbance on the other hand, which can effectively improve the tracking stability and disturbance rejection of the flight control.…”