Research On Anti-rollover Ccontrol Of Vehicle With Air Suspensions

As a daily means of transportation,buses are closely related to people’s lives.Large buses have a large number of passengers,a high center of mass,and heavy weight.They are prone to rollover under high-speed driving and emergency steering conditions.The number of casualties caused by bus rollovers also ranks first in traffic accidents throughout the year.Therefore,the active safety technology of the bus has always been one of the key and difficult points in the vehicle field,and the anti-rollover performance of the bus is also of great significance.The specific research content of this paper is as follows:First,the structure of the air suspension system is introduced.According to the thermodynamic characteristics of the air spring and the working principle of the air suspension system,the mathematical model of the air suspension system is established in MATLAB/Simulink.On this basis,a 1/4 vehicle model is combined to establish a 1/4model of an air suspension vehicle.At the same time,an air suspension 1/4 vehicle model was built in AMEsim,and the correctness of the MATLAB/Simulink model was verified by comparison.Secondly,a six-degree-of-freedom passenger car model is built on the basis of the air suspension model,and the air suspension force is used as the suspension force input of the rollover model.Combined with the characteristics of the height adjustment of the air suspension vehicle,the change of the roll arm length of the bus is considered in the six-degree-of-freedom model,and the mathematical model of the roll arm length of the bus is established.At the same time,this paper studies the rollover evaluation index lateral load transfer rate,and based on the factor of roll arm length,establishes an early warning time model based on the lateral load transfer rate.In the early warning time model,Kalman filter is used to estimate the body roll angle.And built a Trucksim simulation model,and verified its MATLAB/Simulink model according to the dynamic rollover test test and the angle step test.Finally,based on the early warning time and the vehicle rollover model,the anti-rollover control algorithm and vehicle height switching rules of the air suspension bus are studied,and the overall structure of the anti-rollover control system is constructed.Based on the principle of incremental PID control,the principle of PWM pulse width modulation and the reasonable range of air spring error,an incremental active anti-rollover controller is established.Take the pre-warning time as the feedback signal,once the pre-warning time is less than the set value,the active anti-rollover controller will be triggered immediately.The dynamic rollover test and the angle step test are used to verify the active anti-rollover controller and the bus early warning algorithm.In this paper,the air suspension model and the vehicle rollover model are established,and the relationship between the air suspension height change and the rollover model is established through the roll boom length.Established a bus early warning algorithm based on the early warning time and an incremental active anti-rollover controller.The real-time performance of the anti-rollover control system and early warning algorithm is analyzed.