Research On Control Strategy Of Vehicle Electronic Stability Program

The electronic stability program is an electronic device which is developed in recent years. It is inheritance and further expanding of functions of the ABS (antilock brake system) and TCS (traction control system).By control of vehicle yaw moment, ESP system improves the deficiency of ABS and TCS in the lateral stability control. ESP system analyzes and identifies the driver’s driving intentions through monitoring of the sensor and calculation of the electronic control unit, and intervenes and controls to the dangerous driving states to maintain the stability of the vehicle and avoid accidents. The current domestic research on the stability control of automobile driving is still at the starting stage. Thus, to develop stability control system with independent property right is of great significance and value to the development of China’s auto industry.Firstly, because of the nonlinear characteristics of tire which has a great influence on vehicle steering stability, a tire model using the magic formula is built in this paper, and then a two-degree-of-freedom vehicle model and a linear two-degree-of-freedom vehicle reference model are built, as an ideal vehicle driving reference model.As well, through vehicle instability analysis, the two main parameters yaw rate and side slip angle which influence vehicle stability are obtained in this paper, and the relations of the two main parameters and vehicle stability are further studied. Yaw rate and side slip angle are determined as main control parameters of vehicle stability control.Then, the control algorithm of vehicle stability is studied. According to the selection of control parameters and the ideas of PID control and fuzzy control, three control strategies are obtained:PID control based on yaw rate, PID control based on side slip angle and fuzzy PID control based on the two control parameters.In the end, by means of model building, vehicle instability analysis, selection of control parameters and study of control algorithm, MATLAB/SIMULINK simulation module are built. Through front wheel step input and multi-period sinusoidal input, methods of yaw rate PID control, side slip angle PID control and fuzzy PID control are simulated and verified. The results indicate the three control methods can well improve the vehicle stability, while fuzzy control effects are more obvious.