Title: Vehicle stability during braking manoeuvres

Authors: M. El-Gindy, L. llosvai

Addresses: Department of Automobile Engineering, Budapest University of Technology, Hungary. ' Department of Automobile Engineering, Budapest University of Technology, Hungary

Abstract: This paper is concerned with the description of the criterion for vehicle stability during disturbed rectilinear braking manoeuvres. The vector principle is employed in deriving the vehicle equations of motion. The vehicle is represented as a four-wheeled rigid body, constrained to move in the horizontal plane. Small disturbances in longitudinal, lateral velocities and yaw rate are introduced into the vehicle equations of motion. Then, solutions of the resulting system of linear differential equations are examined from the point of view of stability theory. The analysis of results shows that the known stability criterion of the slip ratio of the front wheels being greater than that of the rear wheels is a necessary condition for stability, but if the slip-ratio of the rear wheels is greater than that of the front wheels, the vehicle remains stable provided the vehicle speed is not greater than a critical speed. This critical speed is a new added stability criterion. Effect of tyre characteristics, road surface, and tyre-slip ratio on the critical speed are investigated.

Keywords: vehicle stability; vehicle handling; vehicle modelling; braking manoeuvres; tyre slip ratio; tyre characteristics; road surface; critical speed; vehicle speed.

DOI: 10.1504/IJVD.1980.061067

International Journal of Vehicle Design, 1980 Vol.1 No.3, pp.231 - 238

Published online: 25 May 2014 *

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