Title: Fixed-order H_∞ control of an electric power steering system

Authors: Ai Ping Pang; Hui Zhu; Hong Bo Zhou; Tao Qin; Jing Yang; Dao Yin Long

Addresses: School of Electrical Engineering, Guizhou University, Guiyang 550025, China ' School of Electrical Engineering, Guizhou University, Guiyang 550025, China ' School of Electrical Engineering, Guizhou University, Guiyang 550025, China ' School of Electrical Engineering, Guizhou University, Guiyang 550025, China ' School of Electrical Engineering, Guizhou University, Guiyang 550025, China ' PowerChina Guizhou Engineering Co., Ltd., Guiyang 550025, China

Abstract: The electric power steering (EPS) system has a very small phase margin and it is particularly easy to start oscillation. Therefore, a stable controller is needed to improve the stability margin. In addition, the gain of the torsional moment diagram of the EPS system in different situations exhibits parameter perturbation, which requires the control design to have certain robustness performance and consider all the stability margin, robust performance of the system and the bandwidth requirement of the system. In this paper, the fixed-order H_∞ control design is adopted to form an H_∞ optimisation matrix with multi-dimensional performance output and a third-order fixed-order H_∞ controller is designed. The controller has good robustness performance, high stability margin, and relatively low order compared to the conventional H_∞ controller design, which is convenient for practical applications.

Keywords: fixed-order controller; H_∞ control; electric power steering system; robust stability.

DOI: 10.1504/IJMIC.2021.121831

International Journal of Modelling, Identification and Control, 2021 Vol.37 No.3/4, pp.258 - 266

Received: 27 Sep 2020
Accepted: 06 Jan 2021
Published online: 07 Apr 2022 *

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