Fuzzy logic approach to four-wheel steering of motor vehicle

The paper presents the results of numerical simulation of two concepts of the steering system - a passive (2WS) and a four wheel steering one (4WS). A process of modelling of a vehicle behaviour going along the curvilinear path is described. A full, four wheel car model is used, which performances in time domain are shown. Non-linear relations of the friction forces are taken into consideration. A model of a driver enables two principles of motion: a lane change and a steady state cornering. The realisation of the 4WS control is proposed by means of a fuzzy logic controller. The purpose of this control is to minimise the side-slip angle at the centre of gravity, which finally improves the stability of a vehicle. The results of numerical calculation of a curvilinear motion of a vehicle with 2WS and 4WS steering systems are presented.