Research On The Longitudinal Braking Coordination Control Between Tractor And Semi-Trailer Of Dangerous Goods Semi-Trailer Based On The Electronical Controlled Pneumatic Brake System

Dangerous goods semi-trailer is a kind of large-scale dangerous goods transportation vehicle.Due to the particularity of the goods,its safety is particularly important.The dangerous goods semi-trailer tractor and semi-trailer braking coordination is an important factor to maintain the safety and stability of the vehicle braking process.Dangerous goods semi-trailer is equipped with electronical controlled pneumatic brake system(ECPBS)according to the national standard,which makes the coordinated control of longitudinal braking of tractor and semi-trailer have the basis of implementation.Therefore,based on the ECPBS,this paper researches the longitudinal braking coordination between tractor and semi-trailer of the dangerous goods semitrailer to improve the safety and driving stability of the semi-trailer truck,which has important theoretical significance and engineering application value.The main research work of this paper is as follows:(1)On the basis of introducing the structure and working process of the electronical controlled pneumatic brake system of dangerous goods semi-trailer,taking liquid dangerous goods as an example,the influence of physical characteristics of dangerous goods on the longitudinal braking stability of the vehicle is analyzed.Through analysis,the problem of longitudinal braking uncoordination in the braking process of dangerous goods semi-trailer truck is proposed.In this paper,the analysis of braking dynamics of dangerous goods semi-trailer is used,and the longitudinal force at the traction pin of the dangerous goods semi-trailer is proposed as the evaluation index of longitudinal braking coordination between tractor and semi-trailer of the dangerous goods semi-trailer.(2)Taking a certain type of dangerous goods semi-trailer as an example,the forces on the semi-trailer in the braking process are analysed and a theoretical model of the braking dynamics of the semi-trailer considering the impact of the liquid inside the tank is established.MATLAB/Simulink software and AMESim were used to establish a simulation model of the braking dynamics of a dangerous goods semi-trailer and a simulation model of the pneumatic braking system of a semi-trailer respectively,and a joint simulation model of the longitudinal draft brake coordination of a dangerous goods semi-trailer was established based on the above two simulation models.Finally,Truck Sim software was used to carry out a joint simulation with a liquid longitudinal sway model to verify the correctness of the joint simulation model for longitudinal draft brake coordination on semi-trailers carrying dangerous goods.(3)Based on the electronical controlled pneumatic brake system,the vehicle state estimation technology is adopted to estimate the longitudinal force at the traction pin by using the existing information on the tractor of the dangerous goods semi-trailer,and the estimation algorithm of the longitudinal force of the traction pin of the dangerous goods semi-trailer is proposed.Based on the principle of sliding mode variable structure control,the braking force of a semi-trailer is controlled and a coordinated control method for longitudinal draft braking of a dangerous goods semitrailer is proposed.The effectiveness of the control method is verified through simulation experiments.The research results of this paper have important guiding significance for solving the uncoordinated problem between tractor and semi-trailer in the braking process of dangerous goods semi-trailer,and can effectively improve the braking safety of dangerous goods semi-trailer,which has important engineering application value.