A Study of Vehicle Dynamics Stability Based on Fuzzy Control

Electronic Stability Program (ESP) has become the focus of the study in the field of automotive active safety and chassis control in recent years, which was developed from ABS and TCS. ESP mainly works through adjusting the size and the distribution of the longitudinal tire force. ESP can make vehicle produce effective yaw moment to restrain oversteering or understeering, However, ESP is a typical nonlinear, time-delay, time-varying parameter system and its mathematical model is very complex. It is difficult to design the control model by traditional control theory. Fuzzy control does not depend on a precise mathematical model. It is employed to handle complicated questions of nonlinear dynamics. First, in this paper, the 7-DOF of vehicle dynamics model based on the H. B. Pacejka tyre model (magic formula) and vehicle reference model were established by using the MATLAB/SIMULINK. Then by using fuzzy control principle to direct at the nonlinear, time varying characteristics of the ESP system, a controller of yaw rate based on fuzzy control was designed. An analysis of the simulation results of J-turn and lane change on slippery road surface shows that the present stability control system based on the yaw rate is effective in maintaining the yaw rate and the sideslip angle within the optimal range, thus improving the vehicle stability.