Modelling and Control of a Steer-By-Wire Vehicle

Abstract

In this paper some aspects of the modelling and control of a steer-by-wire vehicle are discussed. A nonlinear simulation model is used to develop an observer which is then used to implement a full sate feedback controller based on that of Whitehead [8]. The Whitehead controller, which decouples sideslip by making use of rear wheel steer, is extended so that the yaw response also becomes a first order system of which the bandwidth can be prescribed. In order to independently control these two modes one needs to make use of two inputs, front and rear steering. This leads to a full four-wheel-steer-by-wire control strategy. The resultant controller improves the dynamics of the vehicle so that it can negotiate a single lane change at a faster velocity, with improved yaw and sideslip response over the original Whitehead controller.