Enhancement of Vehicle Handling using Four Wheel Steering Control Strategy

This paper describes the use of a designed Fuzzy Logic Control for the purpose of integrating the driver’s steering input together with the four-wheel steering system (4WS) in order to improve the vehicle’s dynamic behavior with respect to yaw rate and body sideslip angle. The control objective is to obtain zero body sideslip angle by a two-dimensional rule table, which is created based on the error and on the change in the error of sideslip angle that is to be minimized. The dynamics of the model is developed with a three-degree of freedom nonlinear vehicle model including roll dynamics. The Magic Formula is applied in order to formulate the nonlinear characteristics of the tires. A lane change and steady state cornering simulations are performed to show the effectiveness of the control on transient motion body sideslip angle and yaw rate response time behaviors. During simulations, comparisons are done with the two-wheel steered vehicle and the control techniques studied previously.