Research On The Establishment Of Fluid-solid Model Of Tank Truck And The Control Of Anti-rollover

As the main means of highway transportation of liquefied petroleum products,liquid tank vehicles undertake very important highway transportation tasks.However,as liquid tank vehicles often have high mass,large volume,large cargo capacity,liquid impact inside the tank,it is easy to cause vehicle rollover accidents when making emergency lane change or high-speed curve movement,which causes serious casualties and economic losses.With the rapid development of intelligent assisted driving technology in recent years,the industry has gradually increased the research on anti-rollover control of liquid tank vehicles,and continuously improved the judgment and control effect of the rollover state of liquid tank vehicles.Considering the characteristics of the liquid impact dynamics inside the tank,this thesis takes the elliptical cylindrical liquid tanker as the carrier,equates the motion of the liquid inside the tank to mechanical motion,and a refined mathematical model of the equivalent sloshing of the trammel pendulum is established,then builds the liquid tanker fluid-solid coupling whole vehicle model,finally carries out the reliability of the tank car rollover status identification and the corresponding control strategy research.This thesis mainly focuses on the following aspects:(1)For the characteristics of the elliptical cylindrical tanker under study,firstly,the grid division of the liquid tank and the numerical calculation of the liquid sloshing are carried out based on the FLUENT liquid sloshing numerical model,which provides a comparison model and parameter identification for the accuracy verification of the equivalent model of the liquid in the tank established in this thesis.Secondly,the equivalent liquid lateral sloshing law of the trammel pendulum mathematical model is used,and the sloshing force and sloshing moment of the trammel pendulum equivalent model are derived and calculated,and the accuracy of the equivalent mathematical model established in this thesis is verified by comparing with the FLUENT numerical model under different lateral acceleration excitation.Finally,based on the mathematical model of the liquid lateral nonlinear equivalent sloshing,the mathematical model of the equivalent sloshing of the liquid longitudinal trammel pendulum is further constructed,and the liquid mass transfer model between the chambers in the tank with perforated partitions is derived in depth,and the established mathematical model of liquid longitudinal elliptical pendulum equivalent sway is verified by comparing with the FLUENT simulation numerical model under different longitudinal acceleration excitation.(2)Establish the fluid-solid coupling dynamics model of the tanker truck based on Trucksim software.Firstly,add the sloshing dynamics and sloshing moments of the tanker to Matlab after FLUENT calculations,and then build a sub-model of the equivalent liquid trammel pendulum in the Simulink module,so as to establish a fluid-solid coupling model of the tanker truck,which provides a rapid calculation and a reasonable model foundation for the research on the rollover state recognition and control of the tank truck.(3)Taking the lateral load transfer rate as the rollover index,the KNN classification algorithm is used to build the rollover state discrimination model of the liquid tank vehicle simply and quickly.Meanwhile,based on the reliability theory of Monte Carlo and radius importance sampling,the overturning probability of liquid tank vehicle is calculated.Then,through two typical operating conditions,the overturning probability of discontented liquid tanker and ordinary truck under equal mass is compared and verified,and finally the overturning risk identification of liquid tanker vehicle is achieved.(4)Establish a differential braking control algorithm under the framework of the vehicle electronic stability control system(ESC).By obtaining the real-time steady-state value of the vehicle in the driving process,a simplified three-degree-of-freedom model of the vehicle is established,and the linear quadratic regulator(LQR)is used to obtain the best additional yaw moment when the vehicle responds to the risk of rollover,and this is input to the brake wheel cylinder of the target vehicle to achieve differential braking.Finally using the Trucksim kinematics simulation software and the control module designed in Matlab/Simulink to simulate and verify the limitation of the differential braking control strategy.