Research Of Vehicle's Rollover Prevention Based On Semi-active Steering Technology

Vehicle's rollover is one of the common accidents. But it brings much greater damage than ordinary one. In order to reduce the probability of vehicle rollover, advanced anti-rollover devices need to be designed. The cause of rollover is mostly due to fast speed or oversteering. So the quality of vehicle's steering system is critical to driving stability.In this paper, a new type of steering technology is proposed based on the traditional steering system. It is called semi-active steering. Its strong trait is taking place of the traditional high stiffness torsion shaft with a flexible shaft. So the direct motor could easily modulate the angle of output shaft and achieve variable steering ratio to enhance vehicle stability and avoid vehicle's rollover. The characters of traditional steering system and control method of motor are analyzed by building mathematical model and calculating with software Matlab. A new style of steering system is proposed. The structure and working principle of semi-active steering system are illustrated. The request of the most crucial part flexible shaft and whole system are designed. By using the co-simulation of Amesim and Simulink software, the control algorithm of semi-active steering system is compiled base on the theory of vehicle's rollover. The simulation results show this system and control strategy can effectively enhance vehicle's stability and prevent vehicle's rollover. Opitimazation of the control strategy is the combination control of semi-active steering and differential braking. Simulation result shows it is the optimal control way for vehicles. A vehicle's rollover platform based on semi-active steering sytem is also established. With equipments Labview and some other hardware, experiments are excuted. The testing results show the effectiveness of semi-active system for preventing vehicle's rollover and the data is coincident with theory analysis.In this paper, the semi-active steering system,motor control strategy,simulation and experiments results are very useful for vehicle's anti-rollover analysis work.