Owing to the nonlinearity of the tire, it is difficult to obtain high handling and stability by any one of the existing individual control systems. As an integrated system is necessary to solve this problem, an intelligent vehicle system is expected to be able to adapt to the changing environment, such as changes in the friction coefficient of the road surface, and assist the driver's steering under certain critical driving situations. This paper proposes an intelligent integrated four-wheel-steer and yaw moment control system for this purpose. The system is designed on a model-following basis. The parameters of the vehicle are identified for the calculation of its inverse dynamics. The control inputs to the vehicle are then calculated by using the inverse dynamics. A decision-making part which contains linguistic rules is also designed to determine how the integrated system should be configured. The effectiveness of the proposed system is verified by some results of computer simulation using a nonlinear tire model. The simulation results show that it can reduce the burden of the driver in certain critical driving situations by autonomously adapting to the changing environment, and that the handling and stability of the vehicle are improved significantly. (A)
Abstract