Title: Static and dynamic wheel alignment analysis of steering drift under straight braking

Authors: Y.G. Cho

Addresses: Hyundai Motor Company, 772-1 Jangduk-Dong, Hwaseong-Si, Gyeonggi-Do 445-706, Korea

Abstract: This paper aims to identify the steering drift of a small passenger vehicle under severe straight braking. Steering drift is analysed by gyro and wheel tracker measurements of dynamic wheel alignments, and when compliance is done by Kinematic and Compliance (K&C) machine of static wheel alignment. After braking force is applied at high speed, the toe angle at the front wheel is initially in a toe-in direction owing to longitudinal braking force; subsequently, the toe angle becomes toe-out owing to the wheel bump stroke. To investigate the contribution of suspension parameters that may be difficult to control in field tests, bushing stiffness of the lower control arm, kingpin offset at the ground, caster angle, bump toe angle and wheel weight are simulated in a multi-body software environment. The results show that the dominant factors are the bump toe, caster and the wheel weight difference between the left and right wheels. This approach is useful in setting proper suspension geometry at the stage of conceptual chassis design.

Keywords: steering drift; straight-ahead stability; vehicle braking; wheel alignment; toe angle; vehicle dynamics; small passenger vehicles; severe braking; straight braking; braking force; vehicle suspension; multibody dynamics; simulation; conceptual design; chassis design.

DOI: 10.1504/IJVD.2011.043270

International Journal of Vehicle Design, 2011 Vol.56 No.1/2/3/4, pp.4 - 18

Received: 18 Aug 2010
Accepted: 15 Nov 2010
Published online: 10 Apr 2015 *

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