Title: Kinematics of a steering tyre with adjustable caster

Authors: Dai Vo; Reza Nakhaie Jazar; Mohammad Fard

Addresses: School of Engineering, RMIT University, Melbourne, VIC 3000, Australia ' School of Engineering, RMIT University, Melbourne, VIC 3000, Australia ' School of Engineering, RMIT University, Melbourne, VIC 3000, Australia

Abstract: This paper presents the kinematics of a steerable tyre with a variable caster. It serves as a first step towards developing the theory of variable caster steering in which wheel camber is controlled by the variable caster. The homogeneous transformation was utilised as a tool to develop the kinematics. The wheel camber, extracted from the kinematics, was expressed as a function of steering angle and suspension parameters in general case. The movement of the ground-contact point along the tyre perimeter was also taken into account. The kinematics was developed without small-angle-approximation. Therefore, the kinematic model is applicable to the case of the variable caster. A practical mechanism for the variable caster was also suggested to introduce the idea of the task. The required kinematics of such suspensions is derived from the general case to provide a visual understanding. The kinematics was then validated by a multi-body model built in ADAMS software.

Keywords: variable caster; variable caster steering; kingpin inclination; kingpin axis; steerable tyre kinematics; side slip; lateral force; homogeneous transformation.

DOI: 10.1504/IJVD.2017.085448

International Journal of Vehicle Design, 2017 Vol.74 No.2, pp.134 - 152

Received: 28 Nov 2015
Accepted: 20 Nov 2016
Published online: 26 Jul 2017 *

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