A suspension system with a variable roll centre for the improvement of vehicle handling characteristics

Abstract

In this paper, the improvement of vehicle handling characteristics using variable roll centre suspension (VRCS) is investigated. A vehicle with VRCS can improve stability and ride comfort by automatically controlling suspension geometry in accordance with the running conditions of the vehicle. To achieve this, a variable roll centre concept in the McPherson strut suspension system is suggested, while the two parts most sensitive for controlling the roll centre are suggested. One is between the vehicle body-side connecting portion or the lower arm and the vehicle body (control input, LCZ), and the other is between the vehicle body-side connecting portion of the strut and the vehicle body (control input, STY). Kinematic roll centre analysis, based on the analytic half-car model, shows that the use of two control inputs, LCZ and STY, can decrease migration of the roll centre and centre of gravity according to the side force. In order to quantify the relationship between roll centre and geometry control input and evaluate handling performance, it full vehicle model of 15 degrees of freedom (DOF) is constructed using multi-body dynamic analysis software, ADAMS. In step steering and double lane change manoeuvres, simulation results demonstrate that a vehicle with VRCS adjusts roll centre migration, and handling characteristics such its roll angle, lateral acceleration and yaw rate are much improved.