Title: The relationship between vehicle yaw acceleration response and steering velocity for steering control

Authors: M.J. Thoresson; T.R. Botha; P.S. Els

Addresses: Department of Mechanical and Aeronautical Engineering, University of Pretoria, Pretoria 0002, South Africa ' Department of Mechanical and Aeronautical Engineering, University of Pretoria, Pretoria 0002, South Africa ' Department of Mechanical and Aeronautical Engineering, University of Pretoria, Pretoria 0002, South Africa

Abstract: This paper proposes a novel concept for the modelling of a vehicle steering driver model for path following. The proposed steering driver reformulates and applies the Magic Formula, used for tyre lateral force vs. slip angle modelling as a function of vertical force, to the vehicle's yaw acceleration vs. steering velocity response as a function of vehicle speed. The path-following driver model was developed for use in gradient-based mathematical optimisation of vehicle suspension characteristics for handling. Successful application of gradient-based optimisation depends on the availability of good gradient information. This requires a robust driver model that can ensure completion of the required handling manoeuvre, even when the vehicle handling is poor. The steering driver is applied to a nonlinear full vehicle model of a sports utility vehicle, performing a severe double lane change manoeuvre. Simulation results show excellent correlation with test results. The proposed driver model is robust and well suited to gradient-based optimisation of vehicle handling.

Keywords: driver modelling; magic formula; steering response; tyre characteristics; vehicle handling; mathematical optimisation; yaw acceleration response; steering velocity; vehicle design; tyre lateral force; slip angle modelling; vehicle speed; vehicle suspension; nonlinear modelling; sports utility vehicles; SUVs; double lane changing; lane change manoeuvres; simulation; gradient-based optimisation; full vehicle models.

DOI: 10.1504/IJVD.2014.058487

International Journal of Vehicle Design, 2014 Vol.64 No.2/3/4, pp.195 - 213

Accepted: 02 Jul 2012
Published online: 31 Dec 2013 *

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