Enhanced Vehicle Lateral Stability in Crosswind by Limited State Kalman Filter Four Wheel Steering System

In this work, a theoretical investigation of four-wheel steering (or shortly 4WS) system is presented using a linear model to simulate vehicle handling characteristics. This model incorporates driver';s operation. The simulation concerns the vehicle in straight running while the vehicle is subjected to side wind excitation. Limitations of measurements in practice are supporting the implementation of limited state feedback systems instead of those which are based on full state feedback information. Therefore, the well known Kalman filter algorithm is used in this work to design a practical 4WS control strategy. This practical system uses only feedback signals of lateral acceleration and front steering angle to obtain the control law. Measurement noise is taken into account and results are generated to obtain the step response of the outputs of interest. Comparison between this system, classical 4WS system with LQR feedback gains and the conventional 2WS system are obtained and conclusions are drawn on the benefits and practical implications of these intelligent 4WS.