Vehicle Yawing Stability Control Based On Fuzzy Variable Structure Control

With the popularity of the vehicle, the car has become the important transport for car owners to go out for traveling, visiting friends and relatives. The car is convenient for people to travel and also there is a huge security risk. Especially at high speed or low adhesion coefficient road conditions, when the car subjected to emergency steering, emergency brake and external interference, it is easy to lose stability control. And it may lead to major traffic accidents. There is a growing emphasis on the car’s handling stability. The development of stability system with independent property rights has important research value and social significance to the development of China’s automobile industry.Access to a large of relevant information and establish the control object model. On the basis of magic formula, select nonlinear tire model which has an important impact on the automobile steering characteristic. Then establish a two degrees of freedom linear reference model and two degrees of freedom Vehicle Dynamics Model.In-depth analysis of why the car is instability. It is concluded that the cross swing speed and the sideslip angle are two important control variables affecting the yawing stability of the vehicle. According to an additional yaw moment control stability theory and basing on variable structure control theory, design yaw rate and sideslip angle Variable Structure Controller. Aiming at the chattering problem in sliding mode control, a fuzzy sliding mode control strategy is proposed.Based on the above model, the control variables and control strategy, built the simulation module in Matlab/Simulink. Through input the front wheel angle sinusoidal input and step input. Under the condition of high adhesion coefficient and low adhesion coefficient. The vehicle model of sliding mode control and the vehicle model of fuzzy model control are established, and the model is compared with the whole vehicle model without control. The results show that the fuzzy sliding mode variable structure control strategy is feasible to improve the vehicle handling and stability. This paper has important theory and reference value.