Vehicle lateral stability control based on sliding mode control

In view of the vehicle cornering or path changing under ultimate handling maneuver, a 4-DOF nonlinear vehicle dynamics model which takes the longitudinal velocity, lateral velocity, yaw rate and body roll angle as the state variables is presented. Based on the dynamic analysis, the method which using additional yaw moment produced by different longitudinal braking force among each wheels to improving vehicle handling stability in emergency situations is discussed. Considering the sup angle of the centroid as the one of the vehicle state variables is difficult to measuring, the slip angle estimation method based on vehicle dynamic model and kinematics is designed. And then, based on the theory of sliding model control, the combining sliding mode control system is founded, which taking the vehicle yaw rate and body centroid slip angle errors between the estimated and the real as the input variables, and taking the braking torque and the steering angle as control aims. The simulation results indicate that the control method can effectively improve the vehicle lateral handling stability.