An Improved Fractional-Order Active Disturbance Rejection Control: Performance Analysis and Experiment Verification

Abstract

This paper presents an improved active disturbance rejection control scheme (IFO-ADRC) with an improved fractional-order extended state observer (IFO-ESO). The structural information of the system is utilized in IFO-ESO rather than buried as in the typical fractional-order extended state observer (FO-ESO) and help significantly improve the performance of IFO-ESO and closed-loop system. Compared with the integerorder active disturbance rejection controller (IO-ADRC), the auxiliary tracking controller of IFO-ADRC has a simpler form and fewer parameters need to be tuned. Frequency-domain analysis shows that IFO-ESO has better performance over the larger frequency band than FO-ESO, and time-domain simulation shows that IFO-ADRC has better transient performance and is more robust against the parameter variations than traditional fractional-order active disturbance rejection controller (FO-ADRC) and IO-ADRC. The IFO-ADRC is applied to permanent magnet synchronous motor (PMSM) servo control system and demonstrates its capability in the real-world application.

Internal Model Principle-Based Extended State Observer for the Uncertain Systems with Nonconstant Disturbances

“…Subsequently, Professor Zhiqiang Gao of Cleveland State University in the United States proposed Linear Active Disturbance Rejection Control (LADRC) and its parameter tuning method, introducing the concepts of observer bandwidth and controller bandwidth for LADRC design [11]. The Expansion State Observer (ESO), as a core component of ADRC control technology, has also been widely utilized [12][13][14][15][16]. ESO treats the model mismatch (uncertainty) and external disturbances as new states in the system and extends the state space to observe these new system states, thereby estimating the total disturbance [17].…”