Research On The Integrated Control Strategy Of Minibus Anti Rollover

Recently,with the rapid development of automobile industry,vehicle rollover accident has become an important safety problem of growing concern.It is essential to develop the research of anti-rollover control because the vehicle is easy to roll over in a short time when driving at a high speed or turning in an emergency.As the main means of delivery on the highway in China,the passenger safety of minibus is the top priority of the current traffic safety.Therefore,in order to improve the anti-rollover ability,it studies the integrated control strategy based on active suspension and differential braking.First of all,it analyzes the mechanism and influencing factors of vehicle rollover in accordance with the structure characteristics of minibus.The parametric model of minibus is established,including suspension,brake,tire,steering system and other subsystem.At the same time,the ideal linear 2-dof reference model of minibus and 9-dof dynamic model of whole vehicle are established.The lateral-load transfer rate(LTR)is set as the evaluation index of vehicle rollover,the threshold value of rollover is determined,and the vehicle anti rollover control system is triggered.An anti-rollover control subsystem is developed in accordance with the working principle of active suspension.The difference between vehicle rollover angle and its ideal value is selected as the input of the fuzzy PI controller,and the output is the active control force applied to the suspension,so as to correct the body attitude and enhance its roll stability.Meanwhile,a differential braking anti rollover control subsystem is established in accordance with its control principle.The fuzzy PID control is designed with the control variables of vehicle yaw rate and centroid sideslip angle to present the vehicle from rollover,and to verify the effectiveness of the typical test conditions for the control strategy of subsystem.In order to select a more suitable control method under different driving conditions,the anti-rollover integrated control strategy based on active suspension and differential braking is proposed to design the corresponding integrated control system.The appropriate lower control subsystem in real time is selected by the upper coordination controller according to the running state of the vehicle,that is to say,the vehicle can be controlled by the active suspension control subsystem and the differential braking control subsystem.In the end,the joint simulation model of minibus is established.Based on the related test standard,the proposed anti-rollover integrated control strategy is simulated and verified by three typical test conditions of fishhook,double shift line and angle step.Compared with the vehicle motion parameters under the conditions of integrated control,no control,active suspension control and differential braking control,the results indicate that this anti-rollover integrated control strategy can effectively reduce the rollover angle and yaw rate under extreme conditions,enhance the rollover stability of minibus and decrease the probability of rollover.