Title: Study on parameters affecting steering feel of column assist electric power steering

Authors: Yijun Li; Taehyun Shim; Dexin Wang; Timothy Offerle

Addresses: Department of Mechanical Engineering, University of Michigan-Dearborn, 4901 Evergreen Road, Dearborn, MI 48128, USA ' Department of Mechanical Engineering, University of Michigan-Dearborn, 4901 Evergreen Road, Dearborn, MI 48128, USA ' Ford Motor Company, 20000 Rotunda Drive, Dearborn, MI 48124, USA ' Ford Motor Company, 20000 Rotunda Drive, Dearborn, MI 48124, USA

Abstract: In recent years, the electric power assist steering (EPAS) system, because of its fuel efficiency, cost effectiveness, and additional safety and convenience features, has rapidly replaced the conventional hydraulic power assist steering (HPAS) system. However, there is still need for improvement of the steering feel of EPAS systems compared to HPAS systems. In this paper, the steering feel of the EPAS system is studied by investigating the steering feel metrics. We first introduce a comprehensive model of a column-assisted EPAS (C-EPAS) system consisting of the major components in the system. The steering feel of the C-EPAS system is then investigated through simulation of on-centre steering tests based on the proposed mechanical model with basic power assist control strategies. Various factors affecting the steering feel responses are identified. Finally, by using this knowledge, it is shown that on-centre steering feel can be improved by adjusting the proper parameters in the C-EPAS system.

Keywords: electric power steering; steering feel; steering system; vehicle steering systems; steering friction; steering model.

DOI: 10.1504/IJVD.2018.098941

International Journal of Vehicle Design, 2018 Vol.77 No.3, pp.153 - 179

Received: 16 Jan 2018
Accepted: 31 Dec 2018

Published online: 09 Apr 2019 *

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