Research On Auxiliary Positioning Of Urban Rail Transit Trains In Signal System Fault Environment

In urban rail transit,the signal system is an important system to ensure the safety of line transportation,improve transportation efficiency and improve working conditions.It can realize the functions of train safety interval control,precise positioning and fixed-point parking.When signal equipment or system failures need to be removed from automatic train protection(ATP)operation mode,train operation depends entirely on manual operation and management,which greatly reduces the efficiency of line transportation and increases the risk of accidents.In view of this,this paper studies the scheme of the auxiliary positioning system for urban rail transit trains to ensure the stability and emergency capability of the whole rail transit system under the failure of the signal system.Firstly,the working principle,structure,function and control mode of urban rail transit signal system are comprehensively analyzed.On this basis,the common faults of each subsystem and the serious faults of signal system are analyzed,and the causes,phenomena and effects of various faults on train operation command are summarized,which can provide demand support for the design of train auxiliary positioning system.In the aspect of scheme design of train auxiliary positioning system,this paper analyses the advantages and disadvantages of common train positioning technology,and combines the functional requirements of train auxiliary positioning system and the characteristics of urban rail transit train line,chooses to use inertial navigation technology,radio frequency identification technology and infrared positioning technology for integrated positioning.On this basis,the overall structure of the train auxiliary positioning system is designed,and the functional modules of the system are divided.The functional requirements of each module are further refined,and the working principle of the system is explained.The design of the system scheme and the selection of positioning technology lay the foundation for the establishment of the layout model of auxiliary positioning equipment suitable for the actual needs of the system.In the aspect of building the layout model of auxiliary positioning equipment,this paper analyses the layout objectives and principles of auxiliary positioning equipment based on the functional requirements of the train auxiliary positioning system and the model of train tracking interval.Based on this,a multi-objective optimization model of auxiliary positioning equipment layout is proposed.The model considers two objectives: maximizing the line passing capacity and minimizing the construction cost.On this basis,this paper analyses and compares the common algorithms for solving multi-objective optimization problems,and chooses simulated annealing algorithm and tabu search algorithm as the optimization algorithms for solving this paper,so as to facilitate the comparison of the results.Finally,taking Nanjing Metro Line 4 as an example,a case study is carried out,and the equipment layout scheme under the efficiency strategy and economic strategy is obtained.Through the analysis of the results of the two algorithms,it is found that both algorithms have certain accuracy.Simulated annealing algorithm can solve better optimization scheme,and compare the optimization scheme with the signal system scheme.It is concluded that the optimization scheme in this paper can greatly reduce the construction and operation cost of the system while guaranteeing the metro operation demand.