Study On Vehicle Stability Control System

With the upping of average velocity and density of vehicles, urgent interests were put on vehicle safety. As the latest control techniques, vehicle stability control is the international research focus on the vehicle active safety field. Vehicle stability control can improve handling performance under any situations, and enhance the security at high speed to avoid traffic design and field test validation.As one of the main techniques of vehicle stability control, Direct-yaw-moment control is the latest method of chassis control. By independent controlling training and braking force of four tires, additional yaw moment is generated to make vehicle to follow the driver's command. In this paper, the vehicle system dynamic model consists of 7 DOFs vehicle model, four-wheel-driver power train model, brake system model, H.B.Pacejke tire model. PID control method and fuzzy control method are used to research the system of based on Direct-yaw-moment control. And with the software of Matlab, a simulation analysis is done for proving validate of Direct-yaw-moment control to vehicle stability on theory.Basing on theory analysis, using MC9S12DP256 MCU, hardware of the vehicle stability controller is developed, and using the software development system Code Warrior IDE of Freescale MCU, the vehicle stability controller's software is developed. Using HCS12 of Singhua university and labotatory debice such as signal accur and oscillograph, software and hardware debugging and signal modeling test are done. The debugging and test results analysis prove that the ECU that have been designed can implement the control function basicly.In all, the research results have proven the feasibility and the validity of Direct-yaw-moment control systerm of co-control of PID to vehicle stability. It can be used to develop vehicle stability control system. And all of work have been achieve will be base of a test on real vehicle.