Title: Dynamic behaviour of a tractor/quadaxle trailer with variable length drawbar

Authors: M. El-Gindy

Addresses: Vehicle Dynamics Laboratory, National Research Council of Canada, Canada

Abstract: This paper describes the results of a study of the directional performance of a common Canadian log-hauling truck making use of a tridem-axle tractor, equipped both with and without a forced-steering tag-axle or pusher-axle, in comparison to the conventional fixed tandem-axle tractor. The entire vehicle chosen for analysis consists of a tractor/quadaxle trailer combination; it includes a tractor, a dolly, and a trailer joined to the tractor by a long payload (logs). The dolly, too, is joined to the tractor by a variable length drawbar. The objective is to develop and apply a mathematical model to examine the influence on the vehicle|s directional performance of different steering ratios between the tractor|s front wheels and the tag-axle or pusher-axle. Different methods for selecting the steering ratios are discussed. The vehicle|s directional performance is evaluated against selected performance measures, namely, friction demand at the tractor drive axles, degree of understeer, offtracking, and rearward amplification.

Keywords: directional behaviour; vehicle dynamics; geometric analysis; forced steering axles; logging trucks; modelling; tractor-quadaxle trailer; variable length drawbar; log-hauling trucks; mathematical modelling; friction; understeer; offtracking; rearward amplification; vehicle design.

DOI: 10.1504/IJVD.1992.061722

International Journal of Vehicle Design, 1992 Vol.13 No.2, pp.182 - 200

Published online: 27 May 2014 *

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