Development of the active front steering control strategy for the enhancement of the vehicle cornering performance

This paper presents the active front steering control strategy for the enhancement of the vehicle cornering performance. Unlike the conventional yaw rate-based lateral controller, our approach does not depend on the tire-road friction, by defining a new state variable, that is, slip angle difference between the front and rear wheels. Because the maximum cornering performance of the vehicle is physically limited by the given road friction, this friction information that is nearly difficult to measure or estimate in real time should be predefined when designing the controller. In this study, such a technical difficulty is mainly treated by formulating the model predictive controller that considers the constraints of the state and control. Without defining the varying target state variable according to the driver command, the controller is designed in such a way to track the constant target value, enabling the road friction dependency. The effectiveness of the proposed method was verified through simulation studies.