Research On Modeling And Algorithm Of The Length Of Safety Siding For Urban Rapid Rail Transit Based On Analytic Hierarchy Process

With the deepening of urban construction,more and more cities begin to build urban rapid rail transit lines.As an important distribution line in the city express line,the length of the safety siding has not been clearly calculated.In the code for design of urban rapid rail transit,the fixed value of the length of safety siding cannot adapt to different stations and the regulations of "measures can be taken to shorten the safety siding in special circumstances" also do not give a definite quantifiable calculation method of shortening length.It is a difficult problem for line designers whether the value of safety siding length can be changed with the demand or how to shorten the length of safety siding under special conditions under different lines and different operation scenarios.Therefore,this paper first analyzes and studies the function and types of safety siding from two aspects of basic definition and design specification,and obtains six basic types of safety siding.By analyzing the similar wiring(refuge line and safety distance),we can get the root cause of safety line setting,that is,the signal of train failure.Aiming at the train fault,this paper studies and discusses the fault conditions of ATP system and braking system,takes the brake failure of train braking system as the main influencing factor of safety siding length,and obtains that the calculation of safety siding length is essentially the calculation of train fault braking distance.Secondly,the safety siding length model is calculated,including the research and calculation of ATP protection curve,train braking starting point and braking distance.The typical IEEE safety braking model is used to calculate the ATP protection curve,and the back algorithm is used to calculate the starting point of the train.According to the type of safety siding,it can be divided into two basic models: the safety siding connected with the main line and the safety siding in the form of the turn back line.Through the analysis of the train working conditions before the model triggers emergency braking,the calculation models of safety siding length under four working conditions of traction,braking,cruise and coasting are obtained.The analytic hierarchy process is used to make decisions on the four models,and the main calculation model of safety siding length is obtained.Thirdly,the safety siding length model is calculated,mainly including the research and calculation of train ATP protection curve,train braking distance in case of train braking failure.According to the braking distance of train braking failure,the failure ratio of train braking is proposed.Based on the distribution principle of braking force,the fuzzy-PID control algorithm is used to control the distribution of it in the failure process,and the fault braking distance of train is calculated by Simulink simulation.At the same time,for the demand of shortening the length of safety siding in special circumstances,the effect of braking failure ratio,braking initial speed,line slope and train load on the value range of safety siding length is explored,and a variety of factors are analyzed by using grey relational analytic hierarchy process.Combined with the auxiliary model of safety siding,the length is calculated comprehensively,and the simulation method of random failure is used to verify that the calculated length has 78.6% probability to ensure the safety of train stopping.Finally,according to the above research on the safety siding length model and algorithm,the software designs the calculation software of the length of the safety siding.The software can calculate the length according to the user input data,simulate the train operation,get the safety siding length under the specific requirements,and provide technical reference for the actual line safety siding design.76 figures,18 tables,70 references.