A Simulation & Research On Vehicle Stability Control System Based On Variable Structure Control System With Sliding Mode

Focusing on the yaw moment control for Automotive Stability Control System, the control logic and algorithm of vehicle stability control system (VSC&VDC) on Variable Structure Control System with Sliding Mode are studied, and the simulations are made through some typical cases, and provide the theoretical basis for designing VSC system. Automotive stability control system was developed from ABS. The system goes into effect in condition of great lateral acceleration or big sideslip angle, such as spinning when former axle sideslips or drifting out when after axle sideslip. It prevents vehicle from spinning and drifting out by controlling brakes independently and adjusting yaw moment on vehicle directly. Vehicle model is the foundation of the research on the Automobile Stability Control System. The whole vehicle math model is founded in this paper, and a three-dimensional vehicle model is build by ADAMS software also, it is build model with dynamics of Multi-rigid-body System with Lagrange Method. Based on whole vehicle math model and sliding-mode theory, three control logics and algorithms are built in this paper, they are side-slip sliding-mode control,yaw rate sliding-mode control and modified side-slip angle sliding-mode control. Simulative test are operated in different conditions, such as ice/snow road,wettest road and dry road. From the result, some research has been done to find out the different between sideslip angle sliding-mode control and yaw rate sliding-mode control. All these will be a base for united control of yaw rate and sideslip angle; also a conceptive is established: (1) Sideslip sliding-mode control is superior to yaw rate sliding-mode control due to nonlinear tire characteristics. (2) Comparing to Sideslip sliding-mode control, the control moment of yaw rate sliding-mode control is more small; (3) When sideslip angle is big, the value of sideslip angle and yaw rate in yaw rate sliding-mode control system will appear un-known numerical value. (4) Comparing to Sideslip sliding-mode control, the peak value of control moment of yaw rate sliding-mode control will appear before the peak value of sideslip angle. (5) In yaw rate sliding-mode control system, yaw rate response delay, while sideslip angle response delay in Sideslip sliding-mode control system. (6) When vehicle is steady, Comparing to Sideslip sliding-mode control, sideslip angle is bigger in yaw rate sliding-mode control. Yaw rate is contrarily. (7) When vehicle is un-steady, Comparing to Sideslip sliding-mode control, sideslip angle is smaller in yaw rate sliding-mode control. Yaw rate is contrarily. It also can be found that the VDC can improve the steady-state steering performance and active safety property of vehicle through the research in this paper. And it is an ideal active safety control technology.