Fractional order active disturbance rejection control with the idea of cascaded fractional order integrator equivalence

Pengchong Chen; Ying Luo; WeiJia Zheng; Zhiqiang Gao; YangQuan Chen

doi:10.1016/j.isatra.2020.12.030

Fractional order active disturbance rejection control with the idea of cascaded fractional order integrator equivalence

ISA Trans. 2021 Aug:114:359-369. doi: 10.1016/j.isatra.2020.12.030. Epub 2020 Dec 23.

Authors

Pengchong Chen¹, Ying Luo², WeiJia Zheng³, Zhiqiang Gao⁴, YangQuan Chen⁵

Affiliations

¹ Department of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430070, China.
² Department of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430070, China. Electronic address: ying.luo@hust.edu.cn.
³ School of Mechatronic Engineering and Automation, Foshan University, 33 Guangyun Road, Foshan, China.
⁴ Department of Electrical and Computer Engineering, Cleveland State University, OH 44115, USA.
⁵ School of Engineering, University of California, 5200 N.Lake Road, Merced, CA, 95343, USA.

PMID: 33422333
DOI: 10.1016/j.isatra.2020.12.030

Abstract

This paper presents a fractional order (FO)-active disturbance rejection control (ADRC) with a FO extended state observer (FOESO) design. Applying this FOESO, a typical second order motion plant can be converted into a cascadedfractionalorderintegrator(1∕s^2r;0<r<1) with considering all other dynamics and internal/external disturbances as totaldisturbances. Therefore, a single proportional controller which is not sensitive to system noise can realize a stable control system. According to the frequency characteristics of equivalent FO system model, the FO-ADRC control system is robust to systematic uncertain dynamics and disturbances. Furthermore, without differential action which is needed for the typical double integrator plant control, the proposed control system achieves good robustness to high-frequency noise. Simulation and experiments on PMSM speed servo system are performed, showing that the proposed FO-ADRC behaves better than integer order ADRC (IO-ADRC) and FOPI controller. This FO-ADRC methodology can be simply extended to general control plants.

Keywords: ADRC; FOESO; Fractional order control; PMSM servo system; Robustness.