Car Esp System Simulation And Research

ESP(Electronic Stability Program) is also named VDC(Vehicle Dynamics Control), it has become the focus of the study in the field of automotive active safety in recent years. It can through the comprehensive regulation of the engine torque and wheels braking control to prevent the car from dangerous situations such as the over-steering and under-steering too much which are beyond the scope of the driver’s manipulation. It can realize ideal trajectory travelling, and improve the car’s directional stability and handling characteristics at the same time.The nonlinear "Magic Formula" tire model was adopted in this paper, the vehicle model with seven degrees of freedom and two degrees of freedom model were built by using Matlab/Simulink. Fist, the basic principles and the stability control strategy of vehicle stability control were researched theoretically, including the influence on vehicle stability the road surface status, steering angle and velocity. The yaw rate and vehicle side slip angle are the control variables to be considered in the paper. Vehicle stability control is realized by properly deciding the objective wheel to brake actively. Directing against the nonlinear, time-varying characteristics of ESP system, a kind of self-adaptive fuzzy ESP controller was designed based on fuzzy control theory, which adapted to the changes of the vehicle speed and the road adhesion coefficient according to vehicle information. The results of simulation showed this control method can control vehicle stability at some critical situations such as steering on the low coefficient of friction of road surface at a high speed, make the vehicle run according to the driver’s intention and improve the vehicle handling stability significantly.