Reliability model construction and analysis method of train control system based on operation task division

Abstract

The application provides a train control system reliability model construction and analysis method based on operation task division. The method comprises the following steps: determining a plurality of stage sub-tasks of a train according to a train transport organization process and a train operation task; establishing a plurality of stage reliability models of a train control system with the train as the core according to the plurality of stage sub-tasks; constructing a fault tree of a basic task reliability model of each stage, and converting the fault tree into a binary decision diagram (BDD) representation; obtaining a failure path leading to a basic task of each stage according to the BDD representation of the basic task of each stage, and calculating the reliability of the basic task of each stage according to the failure path of the basic task of each stage and a fault distribution of each specific device; and calculating a reliability index of the entire train transport task based on the reliability of the basic task of each stage. The method can process system behaviors under real-time dynamic running of a train, and can also perform reliability evaluation on the entire train running process, thereby providing technical support for efficient completion of a train transport task.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of train control system analysis, and particularly relates to a train control system reliability model construction and analysis method based on operation task division. BACKGROUND

[0002] How to analyze and evaluate the reliability of the train control system has been a research focus in the field. In order to improve the reliability, the current trend is to create a new generation of train control system which can simplify a large number of ground devices. In 2003, ERTMS (European Railway Traffic Management System) proposed a new train control system ERTMS-Rigional suitable for low-density lines, and its typical feature is to simplify a large number of ground devices. The train-centered train control system transfers part of the control logic of the original ground controller to the on-board device for execution, so as to achieve the purpose of simplifying a large number of ground devices. Of course, this also brings new problems to the system. Compared with the traditional train control system, the train-centered train control system has a dynamic evolution of the interactive environment, and the interface with the ground device changes with the change of the train transportation task, resulting in dynamic adjustment of the system structure.

[0003] At present, the reliability analysis method of the train control system in the prior art is often carried out for a specific set of hardware systems, and is based on the failure probability of components to construct a reliability model of the system and to analyze it through fault tree analysis and other technologies.

[0004] The disadvantages of the above-mentioned reliability analysis method of the train control system in the prior art include that the control mode of the train-centered train control system (the system structure dynamically changes with the train running process) makes it very difficult to construct and analyze the reliability model thereof, and there is a lack of effective means for reliability analysis of the train-centered train control system.

[0005] Most of the reliability analysis methods of the train control system in the prior art adopt static reliability analysis methods. However, the running process of the train is completed by continuous communication and cooperation of multiple train control devices, and single reliability analysis of a device cannot evaluate the reliability of the entire running process. At the same time, the static analysis method cannot handle the change of the number and type of specific devices in the system running process, and there is no reliability evaluation method for the real-time dynamic running process of the system, especially for the train-centered train control system, the control process of the entire system is different with the change of the train position. SUMMARY

[0006] The embodiments of the present application provide a train control system reliability model construction and analysis method based on operation task division, so as to realize reliability evaluation of the entire train running process and provide technical support for efficient completion of the train transportation task.

[0007] To achieve the above object, the present application adopts the following technical solutions.

[0008] A method for constructing and analyzing reliability model of train control system based on operation task division, comprising:

[0009] determining multiple-stage sub-tasks of the train according to train transportation organization process and train operation task;

[0010] establishing a multiple-stage reliability model of train control system with the train as the core according to the multiple-stage sub-tasks;

[0011] constructing a fault tree of reliability model of each stage basic task, and converting the fault tree into a binary decision diagram (BDD) representation;

[0012] obtaining failure paths leading to each stage basic task according to the BDD representation of each stage basic task, calculating the reliability of each stage basic task according to the failure paths of each stage basic task and the failure distribution of each specific device, and calculating the reliability index of the entire train transportation task based on the reliability of each stage basic task.

[0013] Preferably, the determination of the multiple-stage sub-tasks of the train according to the train transportation organization process and the train operation task comprises:

[0014] dividing the train transportation task into several basic tasks, each basic task being from departure from a station to parking at an adjacent station, and each basic task being divided into three links of station departure, interval operation and adjacent station receiving during train operation along the line, and the basic task being confirmed to be completed when the train sequentially completes the station departure, the interval operation and the adjacent station receiving, and the entire train transportation task being confirmed to be completed when the train sequentially completes all the basic tasks.

[0015] Preferably, the establishment of the multiple-stage reliability model of the train control system with the train as the core according to the multiple-stage sub-tasks comprises:

[0016] constructing the reliability model of different links of the train transportation basic task based on the train control system structure with the train as the core, defining Ph i to represent the failure of the i-th basic task during train operation, and defining the failure of the entire train transportation task as Ph M :

[0017] Ph M = Ph1+ Ph2+…+ Ph i

[0018] that is, the failure of any basic task will lead to the failure of the entire train transportation task;

[0019] defining the i-th basic task Phi Three links failure of the train transport task are: failure to depart from the origin station Ph 1i , failure to run between the origin station and the terminal station Ph 2i , failure to arrive at the terminal station Ph 3i , and the calculation is carried out according to the following formula:

[0020] Ph 1i = F 1i

[0021]

[0022]

[0023] Wherein F ji represents the jth link failure condition of the ith basic task is met, represents the failure condition of Ph 1i link is not met, represents the failure condition of Ph 2i link is not met;

[0024] The calculation formula of the failure probability of the whole train transport task is as follows:

[0025]

[0026] Wherein Q ji represents the failure probability of the jth link of the ith basic task.

[0027] Preferably, the fault tree for constructing the reliability model of each stage basic task is converted into BBD representation, including:

[0028] The failure probability of a specific device x n is calculated by its failure probability distribution: the Boolean function h of variable (x1, x2,..., x n ) is determined by the following formula:

[0029]

[0030] Wherein represents the Boolean function when the value of variable x i is 1, represents the Boolean function when the value of variable x i is 0, and the combination of the two Boolean functions h and g is determined by the following formula:

[0031]

[0032] Wherein represents the logical operator, which takes the value of "and" or "or", and the function index(x i) represents the position in the sequence of BDD variables, if index(x i ) < index(x j ), it means the position of x j in the sequence is after x i . The above formula calculates the value of BDD by loop until there is a terminal point 0 or 1 in the BDD.

[0033] Preferably, the failure path of each stage basic task is obtained according to the BDD representation of each stage basic task, the reliability of each stage basic task is calculated according to the failure path of each stage basic task and the failure distribution of each specific device, and the reliability index of the whole train transportation task is calculated based on the reliability of each stage basic task, including:

[0034] The start time of the basic task i is the end time of the basic task i-1, and the start and end times of the basic task i are denoted as t i-1 and t i . For a specific device x, its failure can occur in different basic tasks, and the calculation is simplified by the following formula:

[0035] x(t i , t j ) = 0, if t i > t j

[0036] x(t i1 , t j1 ). x(t i2 , t j2 ) = x(max(t i1 , t i2 ), min(t j1 , t j2 ))

[0037] Where t i1 and t j1 represent the start and end times of the first basic task, t i2 and t j2 represent the start and end times of the second basic task, and x(t i1 , t j1 ) represents an event variable in the BDD, the value of which can be calculated by the following formula:

[0038]

[0039] The failure probability of the device x is calculated by the following formula:

[0040]

[0041] Where fx (t) is a failure density function of the device x;

[0042] According to the BDD representation of the basic tasks of each stage, failure paths leading to the basic tasks of each stage are obtained, devices included in each failure path are acquired, failure probabilities of each failure path are calculated according to the failure probability distribution of the devices, failure probabilities of each failure path corresponding to the basic tasks are summed, failure probabilities of the basic tasks are obtained, and failure probabilities of the entire train transportation task are obtained by summing the failure probabilities of the basic tasks, so that the reliability index of the entire train transportation task is acquired.

[0043] As can be seen from the technical solutions provided by the above embodiments of the present application, the embodiments of the present application propose a real-time dynamic reliability evaluation method suitable for train-centered train control systems based on the multi-stage system theory, compared with the existing train control system reliability analysis method, the method can process the system behavior under the real-time dynamic operation of the train and can evaluate the reliability of the entire train operation process. The method can perform reliability analysis from the train transportation task level, and is not limited to a specific train control device, thereby providing technical support for efficient completion of the train transportation task.

[0044] Additional aspects and advantages of the present application will be described in the following description and will be apparent from the following description and the organization of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0045] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0046] Figure 1 A process flow diagram of a train control system reliability model construction and analysis method based on operation task division provided by the embodiments of the present application;

[0047] Figure 2 A structure diagram of a train-centered train control system provided by the embodiments of the present application;

[0048] Figure 3 A fault tree model schematic diagram of the first, second and third links of a basic task provided by the embodiments in the present application;

[0049] Figure 4 A BDD schematic diagram of the first, second and third links of a basic task provided by the embodiments in the present application. DETAILED DESCRIPTION

[0050] Embodiments of the present application are described in detail below with reference to several specific embodiments, examples of which are illustrated in the accompanying drawings, wherein the same or similar elements are denoted by the same or similar reference signs throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be interpreted as a limitation on the present application.

[0051] Those skilled in the art can understand that, unless specifically stated otherwise, the singular forms "a", "an", and "the" as used herein include plural referents. It should be further understood that the use of the term "include" in the specification of the present application means that the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say that an element is "connected" or "coupled" to another element, it can be directly connected or coupled to the other element, or there can be intermediate elements. In addition, "connected" or "coupled" as used herein can include wireless connection or coupling. The phrase "and / or" as used herein includes any one or more of the associated listed items, and all combinations thereof.

[0052] Those skilled in the art can understand that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as that generally understood by those skilled in the art to which the present application belongs. It should also be understood that terms such as those defined in a general dictionary should be understood to have meanings consistent with those in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as such.

[0053] In order to facilitate the understanding of the embodiments of the present application, the following will be further explained and described with reference to the accompanying drawings in conjunction with several specific embodiments, and each embodiment does not constitute a limitation on the embodiments of the present application.

[0054] The embodiments of the present application provide a train core-based train control system reliability model construction and analysis method, which solves the problem that in the train core-based train control system, the device interaction dynamically changes with the real-time change of train position, which leads to the inability to evaluate the reliability of train operation process.

[0055] The processing flow of the train control system reliability model construction and analysis method based on operation task division provided by the embodiments of the present application is shown in Figure 1 as follows:

[0056] Step (1), determining the multi-stage sub-tasks of the train according to the train transportation organization process and the train operation task;

[0057] Step (2), establishing a multi-stage reliability model of the train-centered train control system according to the multi-stage sub-tasks;

[0058] Step (3), constructing a fault tree of the reliability model of each stage basic task and converting the fault tree into a binary decision diagram (BDD) representation;

[0059] Step (4), obtaining failure paths of each stage basic task according to the BDD representation of each stage basic task, calculating the reliability of each stage basic task according to the failure paths of each stage basic task and the fault distribution of each specific device, and calculating the reliability index of the entire train transportation task based on the reliability of each stage basic task.

[0060] Specifically, step (1) of the method divides the train transportation task into multi-stage sub-tasks according to the train transportation organization process and the train operation task, and the specific process is as follows:

[0061] The railway transportation task is to use the railway line to make the train carrying passengers or goods run along the line to realize the displacement of passengers and goods. The railway line is divided into stations and sections according to the needs of operation organization. Therefore, the train transportation task is divided into several basic tasks, i.e., from one station to the adjacent station to stop; the train runs only when the corresponding basic task is completed in sequence, and the entire transportation task is completed; each basic task is divided into three links of station departure, section running and adjacent station arrival during the train running process, and the basic task is completed only when the train completes the station departure, section running and adjacent station arrival in sequence.

[0062] Step (2) of the method establishes a multi-stage reliability model of the train-centered train control system according to the multi-stage sub-tasks, which includes:

[0063] According to the above sub-task division and the basic principle of train operation control, the reliability model of different links of the train transportation basic task is constructed based on the train-centered train control system structure. Ph i is defined as the failure of the i-th basic task h i during the train running process, and the entire train transportation task can be defined as Ph M :

[0064] Ph M = Ph1+ Ph2+…+ Ph i

[0065] That is, the failure of any basic task will cause the failure of the entire train transportation task.

[0066] For each basic task Ph i, the failure of the third link of the i-th basic task defined by the present application is that the train fails to depart from the starting station Ph 1i , the failure of the third link of the i-th basic task defined by the present application is that the train fails to depart from the starting station Ph 2i , the failure of the third link of the i-th basic task defined by the present application is that the train fails to depart from the starting station Ph 3i , which can be calculated according to the following formula:

[0067] Ph 1i = F 1i

[0068]

[0069]

[0070] wherein F ji represents that the j-th link failure condition of the i-th basic task is met, represents that the failure condition of the Ph 1i link is not met, represents that the failure condition of the Ph 2i link is not met;

[0071] The entire train transportation task failure probability Q M can be calculated by constructing a fault tree model, as shown in the following formula:

[0072]

[0073] wherein Q ji represents the failure probability of the j-th link of the i-th basic task.

[0074] The calculation of the specific fault tree failure probability needs to rely on the specific equipment involved in the specific link and the composition relationship between the equipment. In step (3), first, the reliability model fault tree of each stage basic task needs to be constructed to determine the fault correlation relationship between the specific equipment involved in the task, and then the fault tree is converted into BDD representation for specific solution.

[0075] Step (3), constructing the fault tree of the reliability model of each stage basic task, and converting the fault tree into BDD representation;

[0076] According to the reliability model of each basic task link obtained in step 2 and the specific train control system equipment involved in each basic task link, the BDD of the reliability model is constructed to calculate the failure probability of the specific task. Specifically, the failure probability of a specific device x n can be calculated by its failure probability distribution:

[0077] Variables (x1, x2,..., x nThe Boolean function h of ) is determined by the following formula:

[0078]

[0079] in Indicates when variable x i A Boolean function when the value is 1. Indicates when variable x i The Boolean function when the value of is 0. In BDD, it is also necessary to calculate the failure probability of an "AND" and "OR" relationship between two devices in BDD. The calculation method is as follows: The combination of the two Boolean functions h and g can be determined by the following formula:

[0080]

[0081] Where ◇ represents the logical operator in the fault tree, its value can be "AND" or "OR". The function index(x) i ) represents the position in the BDD variable sequence. If index(x) i ) < index(x) j ), indicating that x in the sequence j The position is at x i The formula above iteratively calculates the value of BDD until a terminal point of 0 or 1 is found. At this point, we can obtain the failure probability of a path in the BDD. If there are multiple failure paths in the component, the failure probability Q of the component can be obtained by summing the results of all failure paths. ji Finally, the failure probability Q of the entire task is calculated by summing the failure probabilities of each stage. M .

[0082] Step (4): Calculate the reliability of the basic tasks at each stage based on the fault distribution of each specific device, and calculate the reliability index of the entire train transportation task based on this.

[0083] To perform quantitative reliability calculations, it is also necessary to consider the time range of different basic tasks (stages). The completion of the entire task must be achieved by completing several basic tasks sequentially. Therefore, the start time of basic task i is the end time of basic task i-1. Based on this, the start and end times of basic task i are denoted as t. i-1 With t i For a specific device x, its failure may occur in different basic tasks (stages). In this case, the calculation can be simplified using the following formula:

[0084] x(t i , t j ) = 0, if t i >t j

[0085] x(t i1 , t j1 ). x(t i2 , t j2 ) = x(max(t i1 , t i2 ), min(t j1 , t j2 ))

[0086] where t i1 and t j1 denote the start and end time of the first basic task (phase), and t i2 and t j2 denote the start and end time of the second basic task (phase). x(t i1 , t j1 ) denotes an event variable in the BDD, the value of which can be calculated by the following formula:

[0087]

[0088] The failure probability of a specific device can be calculated by the following formula:

[0089]

[0090] where f x (t) is the failure density function of device x. Based on the above method, the failure probability of the entire BDD can be calculated, which is the sum of the failure probabilities of each possible failure path in the BDD.

[0091] According to the BDD representation of the basic tasks of each stage, the failure paths leading to the basic tasks of each stage are obtained, the devices included in each failure path are obtained, the failure probability of each failure path is calculated according to the failure probability distribution of the device, the failure probability of each failure path corresponding to the basic task is summed, the failure probability of the basic task is obtained, and the failure probability of each basic task is summed to obtain the failure probability of the entire train transportation task, and then the reliability index of the entire train transportation task is obtained.

[0092] Embodiment One

[0093] This method is illustrated with the vehicle as the core system structure in Figure 2 , ATS represents the ground control center device, OCU represents the object controller, the blue dashed line curve represents the wireless communication between devices, and the dashed line polyline represents the wireless communication mode between the on-board device and the transponder.

[0094] Step 1: Determine multi-stage sub-tasks based on the train transportation organization process and train operation tasks. This invention divides the train transportation task into several basic tasks, namely, departure from one station to stopping at an adjacent station; the entire transportation task is completed only when the corresponding basic tasks are completed sequentially during train operation; each basic task's train operation along the line is divided into three stages: station departure, section operation, and receiving at an adjacent station. The basic task is completed only when the train sequentially completes station departure, section operation, and receiving at an adjacent station.

[0095] Step 2: Establish a multi-stage reliability model for the system based on the multi-stage sub-tasks. This method takes two adjacent railway stations (Station A and Station B) and the section of track between them as an example. The entire transportation task involves transporting passengers or goods from Station A to Station B. The failure of this task can be divided into three stages: failure to depart from Station A (Ph1), failure to operate within the section between Stations A and B (Ph2), and failure to receive the train at Station B (Ph3). Therefore, the failure of the entire transportation task can be represented as:

[0096] Ph M =Ph1 + Ph2 + Ph3

[0097] Ph1 = F1

[0098]

[0099]

[0100] The failure probability of the entire train transportation mission can be calculated using the following formula:

[0101]

[0102] Step (3): Construct the fault tree of the basic task reliability model for each stage, and convert the fault tree into BDD representation;

[0103] Based on the train control system structure centered on the train, corresponding fault tree models are constructed for the three stages of train departure at the station, operation between sections, and train reception at the station, such as... Figure 3 As shown in (a), (b), and (c), in a train control system centered on the train, logic control commands are all executed by onboard equipment. Therefore, a failure to depart from the station may be due to improper control of the switches. Figure 3 (B9), wireless communication failure with other devices ( Figure 3 (B10), failed to execute driving orders ( Figure 3 (B3). Failure to control the switches was caused by the incorrect rotation of the relevant switches required for train operation. Figure 3 (B11), any turnout ( Figure 3 (B13) or Object Controller (OCU) fault (Figure 3 If the failure of the wireless communication cannot control the switch, the system can control the switch directly through the standby ATS, so as to realize the control of the switch. The failure to execute the driving command can be caused by the logic calculation error of the on-board unit, the display error of the DMI or the misoperation of the driver.

[0104] The train interval operation failure is similar to the first link. Compared with the first link failure, the train interval operation does not need to control the switch. The receiving train at the adjacent station in the third link is consistent with the first link.

[0105] The construction of the fault tree is closely related to the actual running position of the train and the layout of the station. For example, when the train departs from station A, the related switches will be included in the fault tree, and the switches unrelated to the departure will not be included in the calculation. For the same reason, since the train is the core of the train control system, the train needs to communicate with other trains on the line to complete the positioning function. Therefore, during the train interval operation task, the establishment of the fault tree is related to the number of trains running on the line at the same time.

[0106] The three-link fault tree is converted into a BDD representation according to the ite rule in step 3 above (see formula (1)), as shown in Figure 4 where the terminal node 1 represents the occurrence of the event, and 0 represents the non-occurrence of the event. The fault trees of different links can be generated by combining the fault trees of the corresponding links. For example, Ph1 is the first link, so its BDD is consistent with the fault tree of this link, as shown in Figure 3 (a) in (a); the second link BDD is based on the successful completion of the first link task, so the BDD of Ph2 is generated by combining (a) and (b) in Figure 3 (b), and the specific method is to rewrite the terminal nodes 0 and 1 of the fault tree of the first link (originally 1 is rewritten as 0, and originally 0 is rewritten as 1) to represent the non-occurrence of the first stage failure, and then combine it with the BDD of Figure 3 (b) to obtain the BDD representation of Ph2, as shown in Figure 4 (a). Similarly, we can obtain the BDD representation of the third link Ph3, as shown in Figure 4 (b).

[0107] Step (4), calculate the reliability of each stage basic task according to the failure distribution of each specific device, and calculate the reliability index of the entire train operation task based on this.

[0108] Taking Ph1 as an example, combining the BDD representation of Ph1 in Figure 3 (a) ( Figure 4 (a)), the paths leading to the failure of Ph1 task are as follows:

[0109] Ph1:

[0110] 1. P1(t0, t1)

[0111] 2.

[0112] 3.

[0113] 4.

[0114] 5.

[0115] 6.

[0116] 7.

[0117] Combination Figure 4 As shown in (a), P1(t0, t1) indicates that device P1 has failed (via edge "1" to node 1). This indicates that device P1 has not failed (through edge 0 to the next node OCU1(t0, t1)), and so on, we can obtain 7 failed paths for this task.

[0118] Therefore, the failure probability of Ph1 is:

[0119]

[0120] in It can be determined by the formula in step 4, that is:

[0121]

[0122] This represents the probability of device x failing. Let λ represent the failure probability density function of the device. x This represents the failure rate of device x. If t0 = 0, then...

[0123] As mentioned above, the specific probability value of device P1 failing (denoted as P1(t0, t1)) can be obtained from... Calculations show that device P1 has not failed (denoted as P1). The specific probability of ) can be determined by The calculation yields the probability of failure for each of the aforementioned paths.

[0124] Similarly, we can calculate the failure probabilities Q2 and Q3 of the second and third stages, and thus obtain the failure probability Q of the entire task. M =Q1+Q2+Q3.

[0125] In the method, the failure rates of the related devices in the system are assumed as shown in the following table, there are 5 groups of related switches when the train departs from the A station, and there are 9 groups of related switches when the train arrives at the B station. M = Q1+ Q2+ Q3= 2.23 x 10 -5 + 1.33 x 10 -5 + 2.25 x 10 -4 = 2.606 x 10 -4 .

[0126] Table 1. Device failure rate (* indicates that the current device has no such function, and the failure rate is assumed)

[0127]

[0128] Compared with the existing train control system reliability analysis method, the embodiment of the application can process the system behavior under the real-time dynamic operation of the train, and can also evaluate the reliability of the whole train operation process. The method can analyze the reliability from the train transportation task level, and is not limited to a specific train control device, thereby providing technical support for efficient completion of the train operation task.

[0129] Those skilled in the art can understand that the drawings are only schematic diagrams of an embodiment, and the modules or processes in the drawings are not necessarily necessary for implementing the application.

[0130] From the above description of the embodiments, those skilled in the art can clearly understand that the application can be implemented by means of software and the necessary general hardware platform. Based on such understanding, the technical solutions of the application can be embodied in the form of a software product, and the computer software product can be stored in a storage medium, such as a ROM / RAM, a magnetic disk, an optical disk, etc., and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0131] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for apparatus or system embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The apparatus and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0132] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for constructing and analyzing a reliability model of a train control system based on operational task division, characterized in that, include: The train's multi-stage sub-tasks are determined based on the train transportation organization process and train operation tasks. A multi-stage reliability model of the train control system with the car as the core is established based on the aforementioned multi-stage sub-tasks. Construct a fault tree for the reliability model of the basic tasks at each stage, and convert the fault tree into a binary decision graph (BBD) representation. The failure paths leading to the basic tasks of each stage are obtained based on the BDD representation of the basic tasks of each stage. Based on the failure paths of the basic tasks of each stage and the fault distribution of each specific device, the reliability of the basic tasks of each stage is calculated. Based on the reliability of the basic tasks of each stage, the reliability index of the entire train transportation task is calculated. The establishment of a multi-stage reliability model for the train control system centered on the car based on the multi-stage sub-tasks includes: Based on the train control system structure with the train as the core, a reliability model is constructed for different stages of the basic tasks of train transportation, and the following definitions are made. Indicates the first train in operation If any one of the basic tasks fails, then the failure of the entire train transportation task is defined as follows: : That is, the failure of any one basic task will lead to the failure of the entire train transportation task. Define the i-th basic task The three failures were: failure to depart from the originating station. It failed to operate in the section between the originating station and the terminal station. Unable to pick up the car at the terminal station The following formula can be used to calculate: in This indicates that the failure condition of the j-th stage of the i-th basic task is met. express The failure conditions of the process are not met. express The failure conditions of the process are not met; The formula for calculating the failure probability of the entire train transportation mission is as follows: in This represents the failure probability of the j-th stage of the i-th basic task.

2. The method according to claim 1, characterized in that, The aforementioned determination of the train's multi-stage sub-tasks based on the train transportation organization process and train operation tasks includes: The train transportation task is divided into several basic tasks. Each basic task is to depart from one station and stop at an adjacent station. The train's operation along the line for each basic task is divided into three stages: departure from the station, operation between stations, and receiving at the adjacent station. The basic task is considered complete when the train completes the departure from the station, operation between stations, and receiving at the adjacent station in sequence. The entire train transportation task is considered complete when the train completes all the basic tasks in sequence.

3. The method according to claim 2, characterized in that, The construction of the fault tree for the basic task reliability model at each stage, and the conversion of the fault tree into BBD representation, includes: A specific device The failure probability is calculated using its failure probability distribution: variables Boolean functions Determined by the following formula: in Indicates when the variable A Boolean function when the value is 1. Indicates when the variable The Boolean function whose value is 0, then the two Boolean functions and The combination is determined by the following formula: in This represents logical operators, whose values ​​are "AND" or "OR", and functions. Indicates the position in the BDD variable sequence, if , indicating that in the sequence The location is The above formula then uses a loop to calculate the value of BDD until it reaches an endpoint of 0 or 1.

4. The method according to claim 3, characterized in that, The method involves obtaining the failure paths leading to the basic tasks at each stage based on their BDD representations, calculating the reliability of each stage's basic tasks based on these failure paths and the fault distribution of each specific device, and then calculating the overall reliability index of the train transportation task based on the reliability of each stage's basic tasks. The start time of basic task i is the same as the end time of basic task i-1. Let the start and end times of basic task i be denoted as... and For a specific device In other words, its failure may occur in different basic tasks, which can be simplified by the following formula: in and This indicates the start and end times of the first basic task. and This indicates the start and end times of the second basic task. The event variable in BDD can be calculated using the following formula: equipment The failure probability is calculated using the following formula: in Let x be the failure density function of device x; Based on the BDD representation of the basic tasks at each stage, the failure paths leading to the basic tasks at each stage are obtained. The equipment included in each failure path is obtained, and the failure probability of each failure path is calculated based on the failure probability distribution of the equipment. The failure probabilities of each failure path corresponding to the basic task are summed to obtain the failure probability of the basic task. The failure probabilities of each basic task are summed to obtain the failure probability of the entire train transportation task, and thus the reliability index of the entire train transportation task is obtained.

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