Abstract: In order to improve the stability and safety of the vehicle during steering,an active steering controller considering the yaw angle velocity and the centroid side declination angle was designed on the basis of the feed-forward control of the ideal transmission ratio.According to the error between the actual value and the ideal value of the state parameter,the active steering controller calculates an additional additional turning angle independent of the driver through the adaptive sliding mode controller to compensate for the front wheel rotation angle,so that the actual response of the car follows the ideal value to improve the stability of the car.Finally,a co-simulation model of steer-by-wire was established in Matlab/Simulink software and Carsim software,and the proposed active steering control strategy was tested under the conditions of double line shift,sinusoidal input,high and low road adhesion coefficients,respectively.The results show that the active steering controller can significantly reduce the error between yaw angular velocity and centroid deflection angle and the ideal value,and improve the stability of the vehicle during steering.

Key words: steer-by-wire system, active front wheel steering, sliding mode control, adaptive approach law