The Study Of The Yaw Moment Control Strategy On The Bus Anti-rollover Stability

In recent years, with the rapid development of national economy in our country,and the increasing need for people to travel,the bus provide a convenient travel, at the same time, there have been serious security issues, that the rollover accident occur repeatedly on the tourist bus and school bus. There has brought a serious threat to the people’s life and property security. Bus with their large capacity, high center of gravity,etc. Rollover accident occurred easily in high speed turning. The study of anti rollover control on the bus has important practical significance to improve the driving safety.First of all, the multiple degree of freedom system model of the bus was established, and the two degree of freedom ideal model and the Dugoff nonlinear tire model. Analysis the reason of the bus rollover, and select the relevant control indicators that can reflect the running status. This article using the lateral load transfer rate as the evaluation index of rollover risk status. Through the comparison of the bus lateral load transfer rate of actual value and the preset threshold value, to detect the potential dangerous situation of rollover.Based on the anti-rollover control mechanism of differential braking and active steering control technology, for the rollover risk situation of the bus when turning at high speed, according to the two control modes have different corrective yaw moment in the anti-rollover control, this article formulated the optimal yaw moment control strategy by using two kinds of control mode at the same time, and reach the purpose of anti rollover control within the shortest time. The target yawing moment fuzzy controller is designed, and the braking torque fuzzy controller. According the target yaw moment to determine the size of the braking torque of each wheel, the control system applying different braking torque on four wheels at the same time, together with the stack angle of active steering, the anti rollover control was implemented on the bus quickly and efficiently.This article use Matlab/Simulink software to establish the optimal yaw moment anti-rollover control system simulation model. The bus turn left as an example, when it is detected that the lateral load transfer rate beyond the preset threshold value, the control system was started. The simulation was carried out at high or low adhesion road and the bus no-load or load condition. The results show that,the yaw moment anti-rollover optimal control strategy established in this article, can control the busrollover in a timely manner. The objective has been achieved that quickly to prevent rollover. It has a certain robustness and adaptive ability.