MODELING AND CONTROL OF A STEER-BY-WIRE VEHICLE

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 de velop 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 extende d so that the yaw response also becomes a first order system of which the bandwidth can be prescribed. In order to independently control the se two modes one needs to make use of two inputs, front and rear steer ing. This leads to a full four-wheel-steer-by-wire control strategy. T he resultant controller improves the dynamics of the vehicle so that i t can negotiate a single lane change at a faster velocity, with improv ed yaw and sideslip response over the original Whitehead controller.