| The prosperous development of the hazardous chemical industry at the same time,the proportion of road transport mode of tank vehicle in the hazardous chemical logistics market is also increasing year by year,and the ensuing road safety problems of tank vehicle can not be ignored.When the tank truck transportation of hazardous chemical goods,tank vehicle accidents will not only lead to casualties and property damage to the accident vehicle,may also lead to leakage,volatilization and explosion of hazardous chemicals to the local personnel,the environment again bring harm.The most serious safety problem faced by the tank vehicle driving process is the vehicle rollover,so this paper focuses on the turning process due to improper operation of the driver,so that the lateral acceleration is too large to cause the problem of rollover.Commercial vehicles generally have the characteristics of high mass and large loading capacity,and these characteristics are the reasons why commercial vehicles are prone to rollover.Compared with ordinary cargo vehicles,when the liquid cargo loaded in the tank vehicle is not fully loaded,the liquid in the tank also has sloshing characteristics during the driving process,so this paper explores the influence of the lateral sloshing of the liquid on the side tilt stability during the steering process,and on this basis the corresponding active control strategy is studied for the problem of side tilt instability during the driving process.The main research work and conclusions of this paper are as follows:(1)The lateral slosh dynamics model of the tank vehicle was constructed.Considering the lateral slosh of the liquid inside the tank during the steering process,an elliptical gauge pendulum model is established for the liquid inside the tank,and a four-degree of freedom model is established for the longitudinal,lateral,transverse and lateral tilt of the tank vehicle as a whole,and the elliptical gauge pendulum model of the liquid and the car model are coupled with the tank as the "link".The validity of the model is verified by comparing the model of the tank vehicle with that of a common cargo vehicle.(2)The lateral stability of the automobile tank truck is analyzed and the vehicle rollover stability evaluation index is constructed.Based on the constructed dynamics model of the tank vehicle,the angular step simulation test of the tank vehicle is carried out with the help of MATLAB simulation tool to obtain the dynamics response of the vehicle under different test conditions.The simulation test compares the dynamic response of the tank vehicle with that of an ordinary truck in terms of tank shape,liquid filling ratio,vehicle input speed and front wheel turning angle respectively,so as to obtain the influence of liquid shaking on the lateral rollover stability of the tank vehicle and lay a theoretical foundation for active safety control.In addition,the new evaluation index constructed by combining the basic stability evaluation index of lateral load transfer rate with Hidden Markov Model has both the role of rollover prediction and can be used as a controller trigger device for active safety control.(3)A study on the control of tank vehicle roll stability based on active front wheel steering and acceleration vector control.The active front-wheel steering control system is used to control the rollover of the vehicle.The control system uses the LTR predicted by CHMM as the trigger device of the controller,combined with a neural network PID controller,which controls the active front-wheel steering mechanism to suppress the rollover tendency of the vehicle when the risk of rollover is predicted.However,since the active front wheel control rollover control principle is to superimpose the steering wheel turning angle in the opposite direction on the basis of the driver’s input,which brings the biggest problem that it will change the driver’s original driving intention,a control strategy needs to be introduced to solve the problem of driving trajectory change-speed control.The control of speed introduces acceleration vector control(GVC),which is designed to imitate the turning operation proposed by the expert driver and can improve the sensitivity and comfort in the turning process.Therefore,using the acceleration vector method to control the speed can not only improve the driving stability and avoid the trajectory change of the vehicle when the vehicle is about to be destabilized,but also improve the turning stability of the vehicle in the case of stable driving.(4)Research on the integrated control system for the roll stability of a tank vehicle.Through the study of two control strategies of active front wheel steering as well as acceleration vector control and the design of the control system,it can be found that the advantages between the two control strategies can be complementary and joint based on their respective control objectives,so in this part the two control strategies are integrated to jointly ensure the safety of driving.The integrated controller designed in this paper is a hierarchical control,which is divided into decision layer,controller assignment layer and execution layer.The main role of the decision layer is to analyze whether the vehicle currently needs stability control,and when it is judged that the vehicle needs the corresponding control system to start intervention,the control signal is passed to the controller allocation layer.After receiving the respective control target,the controller distribution layer calculates the required control amount to pass to the corresponding actuator.Finally,the vehicle actuator in the execution layer reacts to the received control command and converts it into a control action applied to the vehicle. |
