Research On Electric Vehicle Stability Control System Based On Sliding Mode Variable Structure Control Theory

Electric vehicle stability control system is an active safety technology of vehicle. It can improve the controllability and stability of vehicle by restraining the overturning and underturning of vehicle. This paper gives the research of electric vehicle turning stability control and hardware-in-the-loop simulation (HILS) test platform. The object of the research is the dual-rear-wheel independent drive electric vehicle. Using direct yaw moment control method (DYC), an algorithm based on sliding-mode variable structure control theory has been proposed to enhance the handling and stability of electric vehicles. The overall structure of the vehicle handing and stability control hardware-in-the-loop simulation test platform was proposed and experiments were, carried out on this platform.In this paper, a two-degree-of-freedom (2DOF) dynamics model and a perfect linear model of 2DOF were established on the basis of the H.B.Pacejka tire model (Magic Formula). Sideslip angle and yaw rate were chosen to be the main control variables, then the relations between the two variables and stability were analyzed.To improve the electric vehicle stability, the direct yaw moment control method was introduced to enhance curve accelerating (or braking) capability at limiting behavior. Using sliding-mode variable structure control theory, three different kinds of stability control strategies have been designed, they are sideslip angle sliding-mode variable structure control, yaw rate sliding-mode variable structure control, combine control of sideslip angle and yaw rate.In the Matlab/Simulink simulation platform, simulation was conducted to validate the performance of the designed controller by comparing with or without controller, and which control algorithms should be applied in different specifically vehicle working conditions, how the control parameters impact the control quality, how to eliminate vibration in the sliding-mode variable structure control theory have been discussed. The validity and the robustness of the control strategies were proved through the simulation results.Based on dSPACE, hardware-in-the-loop simulation test platform of the electric vehicle handing and stability control has been developed. On this test platform, experimental study for the electric vehicle stability control system designed for this paper was carried out. Experimental results show that the control algorithm designed in this paper has a certain precision and practicality, and lays the solid foundation for the future actual car experiment.