A control method for in-platoon safety protection of a virtual coupled train control system and a storage medium

Abstract

The application discloses a kind of virtual coupling train control system formation inside safety protection control method and storage medium, method includes: step S11: train is according to electronic map, trackside equipment and speed measurement system calculates the position, speed information of train, and the equivalent brake rate of brake stage is calculated according to the average deceleration of emergency braking;Step S12: rear car real-time obtains front car information;Step S13: rear car is according to the real-time state of front car, and plans front car brake model;Step S14: rear car is according to the real-time state of car, and calculates the safety brake curve under the most adverse situation of car;Step S15: rear car will front car most favorable situation's safety brake curve and the safety brake curve of the most adverse situation of car, and relative brake distance's tracking curve is calculated by combining space-time collision avoidance rules.This storage medium stores the computer program used to execute the above method.The application has the advantages of simple principle, can improve the safety between formation inside train and the like.

Description

TECHNICAL FIELD

[0001] The present application mainly relates to the field of virtual coupling technology in urban rail transit, and particularly relates to a control method for in-formation safety protection of a virtual coupling train control system and a storage medium. BACKGROUND

[0002] With the continuous increase of traffic line scale and the increasing passenger flow, the contradiction between the supply of operation capacity and the demand of passenger flow in some lines or local areas is more prominent, and the pain points in the operation scenarios such as tidal passenger flow, collinear lines and express trains at large stations are increasingly highlighted.

[0003] At present, fixed formation trains are used for single line operation in traffic lines, and the control system operates according to fixed intervals, which is difficult to meet the demand of different operation capacities by flexibly deploying the number of vehicles of the train, and there is a situation of insufficient operation capacity in some lines or sections and waste of operation capacity in some lines or sections.

[0004] To solve the above problems, virtual coupling technology emerges as the times require. Virtual coupling refers to that the trains obtain the cooperative perception messages of adjacent trains through wireless communication transmission and active perception, break the existing block limit, and realize the coupling of train-to-train without physical couplings. The train can dynamically change its "composition" during operation, flexibly configure the formation according to the passenger flow, and change the train formation according to the passenger flow demand of different sections and time periods, so as to better adapt to the time and space distribution law of passenger flow. Virtual coupling will build dynamic and flexible train formation based on passenger flow changes, realize the cooperative control operation of multiple trains under intelligent scheduling, and virtual coupling has become the recognized innovative development direction of train operation control system in the future.

[0005] In the virtual coupling system, the tracking interval between the member trains is further reduced, and the ultimate goal is to replace the physical coupling mechanism between two or more trains to improve the line capacity. The core technology of virtual coupling is to further shorten the interval between formation member trains on the basis of safety protection. The control mode based on absolute braking distance cannot further shorten the tracking interval between trains, and the control mode based on relative braking distance is the basic idea of train tracking between formations.

[0006] The model of relative braking distance relies on the information interaction between the two vehicles, uses the speed and other information of the front vehicle to estimate the position of the front vehicle at the parking time, and considers a certain protection distance margin. The rear vehicle protection point is set to a certain position before the current tail position of the front vehicle. In the existing literature and patents, the relative braking distance model is mentioned and studied. According to the distance relationship between the front and rear vehicles, a tracking model is established, or the difference in braking performance between the front and rear trains is considered to increase the time dimension and establish a tracking model. The safety protection model of the rear vehicle is obtained based on the basic safety braking model of IEEE-1474. When planning the safety protection model of the rear vehicle, the braking distance of the front vehicle under the most favorable conditions is generally only considered during the braking phase.

[0007] Some practitioners have proposed a Chinese patent application "Train braking method, device, electronic equipment and storage medium" (CN113401183 A). The invention provides a train braking method, device, electronic equipment and storage medium, wherein the method comprises: determining the ATP protection curve of the current train, the ATP protection curve is determined based on the minimum value in the roof EB speed limit curve, the target EB speed limit curve and the tracking EB speed limit curve of the current train, wherein the EB speed limit curve reflects the corresponding relationship between each position point and the emergency braking trigger speed, the emergency braking trigger speed in the target EB speed limit curve is the trigger speed when braking from the corresponding position point to the target parking position point to reach the preset target speed, and the emergency braking trigger speed in the tracking EB speed limit curve is the trigger speed when braking from the corresponding position point to the target parking position point to stop; based on the ATP protection curve, the current train is controlled to brake, so that the current train can run according to the minimum tracking interval between trains, on the basis of ensuring the running density, the traffic volume is improved, the traction energy consumption is reduced, and energy saving and emission reduction are realized. The deficiency of this technical solution is that: although the basic idea of calculating the safety protection model of the rear vehicle according to the relative braking distance when the train is tracking is proposed. However, this model is still based on the safety braking model of IEEE-1474, only considers the speed characteristics of the front vehicle, i.e. the safety protection model of the rear vehicle when tracking the front vehicle under the condition that the speed of the front vehicle is not zero, and does not conduct in-depth analysis on the entire process of train braking. The obtained model is not the optimal model.

[0008] Another practitioner proposes a Chinese patent application for a cooperative platoon train safety protection method, device, equipment, system and medium (CN 114132366 A), which discloses a cooperative platoon train safety protection method, device, equipment, system and medium. The method includes: obtaining the running state information and distance information of the first train and the second train, and the collision speed of the corresponding platoon of the first train and the second train, wherein the first train and the second train are the adjacent two trains in the platoon; in the case that the first train is in the emergency braking stage, a safety protection model is established according to the running state information, distance information and collision speed of the second train in the driving stage; the safety protection speed of the second train is determined according to the safety protection model, wherein the safety protection speed is used for the second train not to collide with the first train, or to collide at a speed not greater than the collision speed. According to the embodiment of the present application, the problem of the time interval between the front and rear vehicles becoming long and the efficiency of the platoon train entering and leaving the station being low can be solved. The deficiency of this technical solution is that it is based on the safety protection model of IEEE-1474, and different scenarios are distinguished according to the state of the protection curve of the front vehicle and the time required for stopping in the current state, and the state of the rear vehicle and the time required for stopping. In different scenarios, the distance between the front and rear vehicles is calculated in real time. When the distance is greater than 0, the front and rear vehicles will not collide. This processing method is theoretically feasible, but in the actual execution process, the signal does not know which stage of the braking model it is currently in, so it cannot be implemented in practice.

[0009] Another industry practitioner has filed a Chinese patent application entitled "A Train Safety Tracking and Protection Method and Device Based on Relative Speed" (CN 111845862 A). This invention provides a train safety tracking and protection method and device based on relative speed. The method includes: Step 1, tracking the preceding and following trains and using electronic maps and autonomous speed measurement and positioning information combined with train performance to obtain the safe spatiotemporal trajectory information of the train during its stopping process; Step 2, using inter-vehicle communication, the following train obtains the safe spatiotemporal trajectory information of the preceding train; Step 3, the following train, combining the safe spatiotemporal trajectory information of the preceding and following trains, establishes safety conditions based on the constraint that the position of the following train cannot exceed the position of the preceding train at any given time, and solves for the emergency braking trigger EBI speed of the following train; Step 4, the following train compares whether its current measured speed v2(t0) exceeds its EBI speed E2(t0); if v2(t0) > E2(t0), an emergency braking command is output to decelerate the following train to a stop. The shortcoming of this technical solution lies in the fact that: it models the position wave functions of the front and rear vehicles as piecewise functions based on their braking performance, and then analyzes the positions of the two vehicles based on possible combinations of front and rear vehicles, ensuring that the real-time positions of the two vehicles do not collide to guarantee the tracking safety of the two vehicles. However, in actual implementation, due to the communication delay between the front and rear vehicles, the actual spatiotemporal state and the current stage of the train cannot be obtained, thus limiting its practical guiding significance.

[0010] Another researcher proposed "Research on Train Control Technology for Virtual Train Formation, Railway Standard Design (2019.6: 156-159)". This article introduces the research background and basic concepts of virtual train formation, analyzes the problems faced by the existing European Train Control System (ETCS) when applying this technology, and aims to propose a train control technology implementation scheme for virtual train formation. Depending on whether train interval control is protected by the train control system, two schemes are proposed, and their basic principles and the changes required in the existing ETCS specifications are described. In the scheme based on train control system protection, the concept of relative braking distance is introduced, and a method for calculating the speed limit curve based on relative braking distance is proposed, providing a reference for the research of next-generation train control systems. The shortcomings of this technical scheme are: the relative braking distance model for two-car tracking is modeled from both spatial and temporal dimensions, and the minimum value of the two models is taken as the safety protection curve for the following car. As a basic model for two-car tracking, it only considers the speed of the preceding car and does not conduct an in-depth analysis of the entire braking process of the train; the resulting model still has room for improvement. Summary of the Invention

[0011] The technical problem to be solved by this invention is: in view of the technical problems existing in the prior art, this invention provides a control method and storage medium for safety protection within a virtual coupled train control system that is simple in principle, can improve the safety between trains in a formation, and can improve the efficiency of train operation in a formation.

[0012] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0013] A control method for safety protection within a convoy of a virtual coupled train control system includes:

[0014] Step S11: The train calculates its position and speed information based on the electronic map, trackside equipment and speed measurement system, and calculates the equivalent braking rate during the braking phase based on the average deceleration during emergency braking.

[0015] Step S12: The following vehicle obtains real-time information on the position, speed, acceleration, traction / braking status, emergency braking implementation status, and brake cylinder related parameters of the preceding vehicle;

[0016] Step S13: The following vehicle plans the braking model of the preceding vehicle by judging the braking method, braking status, and braking equipment information of the preceding vehicle based on the real-time status of the preceding vehicle.

[0017] Step S14: The following vehicle calculates the safe braking curve under the most unfavorable condition based on the real-time status of the following vehicle;

[0018] Step S15: The following vehicle combines the safe braking curve of the preceding vehicle under the most favorable condition with the safe braking curve of its own vehicle under the most unfavorable condition, and calculates the tracking curve of the relative braking distance by combining the spatiotemporal collision avoidance rules.

[0019] As a further improvement to the method of the present invention: in step S13, when planning the braking model of the preceding vehicle, determining the braking distance of the preceding vehicle under the most favorable condition includes:

[0020] When the following vehicle calculates the most favorable braking distance for the preceding vehicle based on its current position according to the preceding vehicle's speed, acceleration, traction / braking status, and emergency braking status, it determines whether the braking method used by the train is air braking or electric braking based on the train's braking mechanism.

[0021] The following train determines the braking model of the preceding train based on the current speed of the preceding train and the braking method of the preceding train.

[0022] As a further improvement to the method of the present invention, the situation includes:

[0023] The first scenario: The preceding train issues an emergency braking command, and the train is in the early stage of emergency braking establishment; at this time, the braking model of the preceding train is calculated using two stages: the complete emergency braking establishment stage and the emergency braking implementation stage.

[0024] The second scenario: The preceding vehicle is in a certain stage of emergency braking establishment, but the emergency braking has not yet been fully established. In this case, the relevant parameters of the brake cylinder synchronized with the preceding vehicle's status are used to accurately calculate which stage of emergency braking establishment the train is in. The braking model of the preceding vehicle adopts two stages for calculation: partial emergency braking establishment and emergency braking implementation.

[0025] The third scenario: The emergency braking of the vehicle in front has been established. The braking model of the vehicle in front is calculated in two stages using emergency braking, and finally the braking distance and stopping position of the vehicle in front under the most favorable conditions are obtained.

[0026] As a further improvement to the method of the present invention: the speed model of the preceding vehicle is as follows:

[0027]

[0028] Wherein, the speed of the preceding vehicle is V, V1 is the speed value corresponding to the end of the first stage of the preceding vehicle, V2 is the speed value corresponding to the end of the second stage of the preceding vehicle, V3 is the speed value corresponding to the end of the third stage of the preceding vehicle, the corresponding acceleration is α, the speed measurement error is θ, and the equivalent emergency braking rate is B. e The equivalent gradient acceleration of the vehicle in front is γ; k is the emergency braking proportional coefficient; t0 is the end time of the traction cut-off phase; t1 is the end time of the coasting phase; t2 is the end time of the emergency establishment phase.

[0029] As a further improvement to the method of the present invention: In the first case, the vehicle in front has a complete emergency braking establishment phase and a complete emergency braking phase:

[0030]

[0031] Where L is the total distance traveled by the preceding vehicle during the emergency braking application and braking phase, the speed measurement error is θ, V2 is the speed value of the preceding vehicle at the end of the second phase, V3 is the speed value of the preceding vehicle at the end of the third phase, and the equivalent emergency braking rate is B. e The equivalent gradient acceleration of the vehicle in front is γ; k is the emergency braking proportional coefficient; t1 is the time when the coasting phase ends; t2 is the time when the emergency establishment phase ends.

[0032] The speed model of the vehicle in front is:

[0033]

[0034] Wherein, the speed of the preceding vehicle is V, V1 is the speed value corresponding to the end of the first stage of the preceding vehicle, V2 is the speed value corresponding to the end of the second stage of the preceding vehicle, V3 is the speed value corresponding to the end of the third stage of the preceding vehicle, the corresponding acceleration is α, the speed measurement error is θ, and the equivalent emergency braking rate is B. eThe equivalent gradient acceleration of the vehicle in front is γ; k is the emergency braking proportional coefficient; t0 is the end of the traction cut-off phase; t1 is the end of the coasting phase; t2 is the end of the emergency braking establishment phase; the initial speed of the emergency braking phase is the instantaneous speed at the end of the emergency braking establishment phase, and t is taken as t2.

[0035] As a further improvement to the method of the present invention: In the second case, the vehicle in front has a partial emergency braking initiation phase and a complete emergency braking phase:

[0036]

[0037] t1<Δt <t2

[0038] Where l is the travel distance of the train during the traction phase and the partial emergency braking phase, Δt is the time required for the train's emergency braking to fully establish, V3 is the speed value of the preceding train at the end of the third phase, and the equivalent emergency braking rate is B. e The equivalent gradient acceleration of the preceding vehicle is γ; the speed of the preceding vehicle is V; and k1 is the emergency braking proportional coefficient, calculated based on the real-time braking parameters of the train.

[0039] As a further improvement to the method of the present invention: in the third case, the vehicle in front only has an emergency braking phase, without traction, coasting, and emergency braking establishment phases.

[0040]

[0041] Where L is the train travel distance in the last stage of emergency braking, V3 is the speed value of the preceding train at the end of the third stage, the emergency speed measurement error is θ, and the equivalent emergency braking rate is B. e The equivalent gradient acceleration of the vehicle in front is γ. The initial velocity during the braking phase is the instantaneous velocity at the end of the emergency braking initiation phase, so t is taken as t2.

[0042] As a further improvement to the method of the present invention: in step S11, the virtual coupled member cars calculate their own position information and speed information based on the stored electronic map data and speed measurement and positioning system; and calculate the equivalent emergency braking rate of the train during the braking phase from the average deceleration of the train during emergency braking given in the vehicle performance parameters.

[0043] As a further improvement to the method of the present invention: in step S14, the following vehicle is considered according to the braking distance of the following vehicle under the most unfavorable condition, including track conditions; information on traction cut-off delay, coasting delay and braking establishment delay in the train performance parameters; and then the braking distance of the following vehicle in all stages is calculated according to the IEEE1474 safe braking model.

[0044] The present invention further provides a storage medium that can be read by a computer or processor, wherein the storage medium stores a computer program for executing any of the above methods.

[0045] Compared with the prior art, the advantages of the present invention are as follows:

[0046] 1. The present invention relates to a control method and storage medium for safety protection within a virtual coupled train control system. The principle is simple, and it can improve the safety between trains within the formation and improve the efficiency of train operation. The present invention optimizes the safety protection model of the rear train based on the safety protection model derived from the spatiotemporal position relationship between the front and rear trains, and further shortens the interval between trains in the formation.

[0047] 2. This invention discloses a control method and storage medium for safety protection within a virtual coupled train control system. It fully utilizes vehicle-to-vehicle communication among virtual coupled train members to acquire real-time information such as the speed, position, traction / braking status, and real-time status of key braking equipment of the preceding vehicle. It determines the real-time status of the preceding vehicle (i.e., acceleration or braking). If the preceding vehicle is braking, based on the different braking implementation methods under different scenarios, the braking status is refined into air braking or electric braking. Finally, according to the braking method and stage of the preceding vehicle, the braking curve is refined into the travel distance of the braking stage or the travel distance of the braking establishment stage plus the braking implementation stage. The refined processing of the preceding vehicle's braking model in the relative braking distance model, recreating the tracking scenario of the two vehicles based on the actual braking mechanism of the train, ensures that the two vehicles will not collide due to the preceding vehicle's braking, while further shortening the tracking interval.

[0048] 3. The present invention provides a control method and storage medium for safety protection within a convoy of a virtual coupled train control system. It refines the safety protection model based on relative braking distance, further shortening the distance between trains and improving the system's kinetic energy while satisfying spatiotemporal collision avoidance.

[0049] 4. The control method and storage medium for safety protection within the formation of a virtual coupled train control system of the present invention, although mainly based on the train control system or virtual coupled system based on car-to-car communication, are also applicable to the traditional CBTC architecture. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the IEEE-1474 train safety braking model.

[0051] Figure 2 This is a schematic diagram illustrating the principle of the relative braking distance model based on spatiotemporal collision avoidance in a specific application example of the present invention.

[0052] Figure 3 This is a schematic diagram of the optimized relative braking distance model of the present invention in a specific application example.

[0053] Figure 4 This is a flowchart illustrating the method of the present invention in a specific application example. Detailed Implementation

[0054] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0055] This invention proposes a method for safety protection within a virtual train coupling formation. After the virtual coupling of trains is completed and a virtual coupling formation is formed, it is used to ensure that the lead car and slave cars, as well as the slave cars and their preceding trains, maintain a safe distance to avoid rear-end collisions.

[0056] To more clearly illustrate the content of the method of the present invention, the following technical features of virtual linked formations are first described:

[0057] The lead car: The car in a virtual coupled convoy responsible for external communication, internal collaborative protection, and collaborative operation; it is the first train in the convoy.

[0058] From the train: The following train behind the main train in a virtual convoy.

[0059] Preceding vehicle: A vehicle in front of another vehicle in a virtual trailer convoy, but not the lead vehicle.

[0060] The core of the safety protection proposed in this invention refers to the following: During the operation of a virtual convoy, when the lead vehicle or the preceding vehicle brakes, the following vehicles can maintain a certain safe distance from the lead vehicle or the preceding vehicle when they come to a complete stop, thus avoiding rear-end collisions. Specifically, it is the minimum safe distance obtained through logical calculation when the lead vehicle or the preceding vehicle brakes fastest under the "most favorable condition" and the following vehicle brakes slowest under the "most unfavorable condition." Wherein:

[0061] The most favorable situation for the train refers to the situation where the train uses the maximum braking rate, the optimal gradient, and the optimal system response.

[0062] The worst-case scenario for a train refers to a situation where the train's brakes are worn out, the braking rate is at its minimum, the gradient is the most unfavorable, and the delays in various systems are significant.

[0063] The optimal gradient refers to the gradient acceleration of the train during braking when it is on the maximum uphill slope (the acceleration that makes the train stop faster). When there is no uphill slope but there is a flat slope, it is treated as a flat slope; otherwise, it is treated as the minimum value among all downhill slopes.

[0064] The most unfavorable gradient refers to the situation during train braking where, if there is an uphill slope, it is treated as a level slope; if there is no uphill slope but there is a level slope, it is treated as a level slope; otherwise, it is treated as the maximum value among all downhill slopes.

[0065] For vehicle braking, it generally consists of electric braking and air braking. Train braking methods vary depending on the operating scenario, and can be categorized into three types: electric braking, air braking, and a combination of both. Under normal circumstances, when the train speed exceeds a specified value (T), braking is achieved through electric braking. However, in abnormal situations such as skidding, the system switches from electric braking to air braking. When the train speed is below T, braking is achieved through air braking. Emergency braking is always achieved through air braking. If the train is initially braking electrically and receives an emergency braking command, it will disengage the current electric braking and reapply emergency braking. Furthermore, electric braking has a shorter application time, while air braking has a longer application time.

[0066] This invention further optimizes the relative braking distance model between virtual trailer platoon members based on time and position relationships. Specifically, it optimizes the braking model of the preceding vehicle in the relative braking distance model calculated for the following vehicle, thereby further shortening the distance between the two vehicles while ensuring the safety of the platoon members and preventing collisions. Therefore, this invention is of great significance to virtual trailer systems.

[0067] The theoretical basis of the relative braking distance model remains the IEEE-1474 safe braking distance model. This model fully considers the time from the change in train traction state to the actual effectiveness of train braking, the train's travel distance during this time, and forms the train's safety protection curve accordingly. Sections A and B represent the period from when the ATP sends the traction cut-off command to when the vehicle actually cuts off the traction; section C is the coasting phase after traction cut-off; section D is the period from the application of emergency braking to when the braking force reaches 90%; and section E is the emergency braking phase. (See...) Figure 1 .

[0068] In the aforementioned relative braking distance model, the differences in speed and braking performance of the preceding vehicle are fully considered, and a safety protection model is derived based on the spatiotemporal position relationship. Furthermore, the braking model for the following vehicle is the most unfavorable safety braking model, while the braking model for the preceding vehicle is the most favorable braking model. That is, the following vehicle uses the full-stage model from the IEEE-1474 safety braking model, while the preceding vehicle only considers the final stage (braking stage). (See...) Figure 2 .

[0069] The present invention discloses a control method for safety protection within a convoy in a virtual coupled train control system, which optimizes the leading vehicle braking model in the relative braking distance model. Specifically, the real-time status of the leading vehicle is accurately determined based on the real-time acquired position, speed, traction / braking status, and status of key braking equipment of the leading vehicle. When the leading vehicle is braking, the method of braking used by the leading vehicle is accurately distinguished as electric braking or air braking. Based on the braking method implemented by the leading vehicle, the braking model of the leading vehicle is further planned into several cases: a braking establishment phase plus an emergency braking phase, a partial emergency braking establishment phase plus an emergency braking phase, or only an emergency braking phase.

[0070] The value of the emergency braking establishment segment needs to be further determined based on the degree of braking applied by the preceding vehicle; therefore, the emergency braking establishment segment can also be called a variable segment. The optimized relative braking distance model, obtained by refining the braking process of the preceding vehicle, will further shorten the safe distance between the two vehicles. (See...) Figure 3 .

[0071] Based on the above principles, the relative braking distance safety model can be expressed in three ways depending on the actual state of the vehicle in front:

[0072] Let the speed of the vehicle in front be V, the speed measurement error be θ, and the equivalent emergency braking rate be B. e The equivalent gradient acceleration of the preceding train is γ; the speed of the following train is v, the speed measurement error is ε, the equivalent emergency braking rate is ζ, the equivalent gradient acceleration is η, the corresponding acceleration is a, the traction cut-off time is t0, the coasting time is t1, the emergency braking establishment time is t2, and f(t) is the minimum safe distance between the two trains.

[0073] f(t) = f1(t) - f2(t) + e(t)

[0074] Where f1(t) is the calculated distance when the following vehicle applies emergency braking, f2(t) is the calculated distance when the preceding vehicle applies emergency braking, and e(t) is the error and margin.

[0075]

[0076]

[0077] e(t)=Δtv(1+ε)+(a-η)Δt 2 / 2+E

[0078] Let the speed of the vehicle in front be V, the speed measurement error be θ, and the equivalent emergency braking rate be B. eThe equivalent gradient acceleration of the preceding train is γ; the speed of the following train is v, the speed measurement error is ε, the equivalent emergency braking rate is ζ, the equivalent gradient acceleration is η, the corresponding acceleration is a, the traction cut-off time is t0, the coasting time is t1, the emergency braking establishment time is t2, f(t) is the minimum safe distance between the two trains, and Δt is the time of partial emergency braking of the train.

[0079] f(t) = f1(t) - f2(t) + e(t)

[0080] Where f1(t) is the measured distance when the following vehicle applies emergency braking, f2(t) is the measured distance when the preceding vehicle applies emergency braking, and e(t) is the error and margin.

[0081]

[0082]

[0083] e(t)=Δtv(1+ε)+(a-η)Δt 2 / 2+E

[0084] Let the speed of the vehicle in front be V, the speed measurement error be θ, and the equivalent emergency braking rate be B. e The equivalent gradient acceleration of the preceding train is γ; the speed of the following train is v, the speed measurement error is ε, the equivalent emergency braking rate is ζ, the equivalent gradient acceleration is η, the corresponding acceleration is a, the traction cut-off time is t0, the coasting time is t1, the emergency braking establishment time is t2, f(t) is the minimum safe distance between the two trains, and Δt is the time of partial emergency braking of the train.

[0085] f(t) = f1(t) - f2(t) + e(t)

[0086] Where f1(t) is the calculated distance when the following vehicle applies emergency braking, f2(t) is the calculated distance when the preceding vehicle applies emergency braking, and e(t) is the model error and margin.

[0087]

[0088]

[0089] e(t)=Δtv(1+ε)+(a-η)Δt 2 / 2+E

[0090] Where k is the emergency braking proportionality coefficient, k1 is the emergency braking ratio coefficient of the preceding train, and k2 is the emergency braking ratio coefficient of the following train. A is the train's emergency braking performance parameter. Δt is the communication delay between the preceding and following trains; E is the initial safe distance, taking into account environmental factors, positioning errors, etc.

[0091] SeeFigure 4 The present invention discloses a control method for safety protection within a convoy of a virtual coupled train control system, the specific process of which includes:

[0092] Step S11: The train calculates its position, speed, and other information based on the electronic map, trackside equipment, and speed measurement system; and calculates the equivalent braking rate during the braking phase based on the average deceleration during emergency braking.

[0093] That is, the virtual coupled member cars calculate their own position and speed information based on the stored electronic map data and speed measurement and positioning system; and calculate the equivalent emergency braking rate of the train during the braking phase from the average deceleration of the train during emergency braking given in the vehicle performance parameters.

[0094] Step S12: The following vehicle obtains real-time information such as the position, speed, acceleration, traction / braking status, emergency braking implementation status, and brake cylinder parameters of the preceding vehicle;

[0095] Step S13: The following vehicle plans the braking model of the preceding vehicle by judging the braking method, braking status, and braking equipment information of the preceding vehicle based on the real-time status of the preceding vehicle.

[0096] Step S14: The following vehicle calculates the safe braking curve under the most unfavorable condition based on the real-time status of the following vehicle;

[0097] Step S15: The following vehicle combines the safe braking curve of the preceding vehicle under the most favorable condition with the safe braking curve of its own vehicle under the most unfavorable condition, and calculates the tracking curve of the relative braking distance by combining the spatiotemporal collision avoidance rules.

[0098] In a specific application example, step S13, when planning the braking model of the preceding vehicle, determines the braking distance of the preceding vehicle under the most favorable condition. The specific process may include:

[0099] When the following train calculates the most advantageous braking distance for the preceding train based on its current position, according to the preceding train's speed, acceleration, traction / braking status, and emergency braking status, it first determines whether the train is using air braking or electric braking based on the train's braking mechanism.

[0100] Furthermore, in practical applications, the following train determines the braking model of the preceding train based on the current speed and braking method of the preceding train, which can be divided into three cases:

[0101] The first scenario: The preceding train issues an emergency braking command, and the train is in the early stage of emergency braking establishment; at this time, the braking model of the preceding train is calculated using two stages: the complete emergency braking establishment stage and the emergency braking implementation stage.

[0102] The second scenario: The preceding vehicle is in a certain stage of emergency braking establishment, but the emergency braking has not yet been fully established. In this case, the exact stage of emergency braking establishment that the train is in is calculated based on the relevant parameters of the brake cylinder synchronized with the preceding vehicle's status. The braking model of the preceding vehicle uses a two-stage calculation: partial emergency braking establishment + emergency braking implementation.

[0103] The third scenario: The emergency braking of the vehicle in front has been established. The braking model of the vehicle in front is calculated in two stages using emergency braking, and finally the braking distance and stopping position of the vehicle in front under the most favorable conditions are obtained.

[0104] Let the speed of the vehicle in front be V, the corresponding acceleration be α, the speed measurement error be θ, and the equivalent emergency braking rate be B. e The equivalent gradient acceleration of the vehicle in front is γ;

[0105] The speed model of the vehicle in front is:

[0106]

[0107] Wherein, the initial speed of the preceding vehicle is V, V1 is the speed value corresponding to the end of the first stage of the preceding vehicle, V2 is the speed value corresponding to the end of the second stage of the preceding vehicle, V3 is the speed value corresponding to the end of the third stage of the preceding vehicle, the acceleration is α, and the equivalent emergency braking rate is B. e The equivalent gradient acceleration of the vehicle in front is γ; k is the emergency braking proportional coefficient; t0 is the end time of the traction cut-off phase; t1 is the end time of the coasting phase; t2 is the end time of the emergency establishment phase.

[0108] Therefore, the braking models for the vehicle in front in the above three situations are as follows:

[0109] In the first scenario, the vehicle in front has a complete emergency braking initiation phase and a complete emergency braking phase:

[0110]

[0111] Where L is the total distance traveled by the preceding vehicle during the emergency braking application and braking phase, the speed measurement error is θ, V2 is the speed value of the preceding vehicle at the end of the second phase, V3 is the speed value of the preceding vehicle at the end of the third phase, and the equivalent emergency braking rate is B. e The equivalent gradient acceleration of the vehicle in front is γ; k is the emergency braking proportional coefficient; t1 is the time when the coasting phase ends; t2 is the time when the emergency establishment phase ends.

[0112] The initial velocity during the emergency braking establishment phase is the instantaneous velocity at the end of the coasting phase, so t is taken as t1; the initial velocity during the emergency braking phase is the instantaneous velocity at the end of the emergency braking establishment phase, so t is taken as t2.

[0113] In the second scenario, the vehicle in front exhibits both a partial emergency braking initiation phase and a complete emergency braking phase:

[0114]

[0115] t1<Δt <t2

[0116] Where V3 is the speed value corresponding to the end of the third stage of the preceding vehicle, the speed measurement error is θ, and the equivalent emergency braking rate is B. e Δt is the time required for the train's emergency braking to fully establish, the equivalent gradient acceleration of the preceding train is γ, k is the emergency braking application proportional coefficient, t1 is the time when emergency braking begins, and t is the time when emergency braking is applied, calculated based on the train's real-time braking parameters.

[0117] Δt is the time required for the train's emergency braking to fully establish, calculated based on the train's real-time braking parameters;

[0118] In the third scenario, the vehicle in front only has an emergency braking phase, without traction, coasting, or emergency braking initiation phases:

[0119]

[0120] Where V3 is the speed value corresponding to the end of the third stage of the preceding vehicle, the speed measurement error is θ, and the equivalent emergency braking rate is B. e The equivalent gradient acceleration of the vehicle in front is γ.

[0121] The initial velocity during the emergency braking phase is the instantaneous velocity at the end of the emergency braking establishment phase, so t is taken as t2.

[0122] In a specific application example, in step S14, the following vehicle considers the braking distance of the following vehicle under the most unfavorable condition, including track conditions such as gradient, track speed limit, and curvature; information such as traction cut-off delay, coasting delay, and brake establishment delay in the train performance parameters; and calculates the braking distance of the following vehicle at all stages according to the IEEE 1474 safe braking model.

[0123] The braking model of the rear vehicle is:

[0124] L = L1 + L2 + L3

[0125] Where L is the travel distance under emergency braking conditions of the following vehicle, L1 is the travel distance of the traction cut-off segment and coasting segment, L2 is the travel distance of the emergency braking segment, and L3 is the travel distance of the variable segment.

[0126]

[0127]

[0128]

[0129] Where k is the emergency braking application ratio coefficient; t0 is the end time of the traction cut-off phase; t1 is the end time of the coasting phase; and t2 is the end time of the emergency braking establishment phase. The following vehicle speed is v, the speed measurement error is ε, the equivalent emergency braking rate is ζ, the equivalent gradient acceleration is η, the corresponding acceleration is a, the traction cut-off time is t0, the coasting time is t1, and the emergency braking establishment time is t2.

[0130] The following train stops at the most advantageous position for the preceding train, while also taking into account the train's communication delay, signal system processing delay, speed measurement error, installation error, etc.

[0131] f(t)=Δtv(1+ε)+(a-η)Δt 2 / 2+E

[0132] Wherein, Δt is the communication delay between the front and rear vehicles, including transmission delay and signal processing delay, which is calculated in real time according to the actual situation.

[0133] Based on the above process, a safety protection model for following vehicles during virtual platoon member vehicle tracking is derived, which can be divided into three cases:

[0134] Scenario 1: The vehicle in front is in the emergency braking phase, while the vehicle behind is in the full braking phase.

[0135] f(t) = f1(t) - f2(t) + e(t)

[0136] Where f1(t) is the calculated distance when the following vehicle applies emergency braking, f2(t) is the calculated distance when the preceding vehicle applies emergency braking, and e(t) is the model error and margin.

[0137]

[0138]

[0139] e(t)=Δtv(1+ε)+(a-η)Δt 2 / 2+E

[0140] Where k1 is the emergency braking ratio coefficient of the preceding vehicle, and k2 is the emergency braking ratio coefficient of the following vehicle; t0 is the end time of the traction cut-off phase; t1 is the end time of the coasting phase; and t2 is the end time of the emergency braking establishment phase. The following vehicle's speed is v, its speed measurement error is ε, its equivalent emergency braking rate is ζ, its equivalent gradient acceleration is η, its corresponding acceleration is a, the traction cut-off time is t0, the coasting time is t1, and the emergency braking establishment time is t2.

[0141] Scenario 2: The braking model of the preceding vehicle represents the partial stage of emergency braking setup and the emergency braking implementation stage, while the following vehicle represents the full braking stage.

[0142] f(t) = f1(t) - f2(t) + e(t)

[0143] Where f1(t) is the calculated distance when the following vehicle applies emergency braking, f2(t) is the calculated distance when the preceding vehicle applies emergency braking, and e(t) is the model error and margin.

[0144]

[0145]

[0146] e(t)=Δtv(1+ε)+(a-η)Δt 2 / 2+E

[0147] The speed of the vehicle in front is V, the speed measurement error is θ, and the equivalent emergency braking rate is B. e The equivalent gradient acceleration of the vehicle in front is γ; the speed of the vehicle behind is v, the speed measurement error is ε, the equivalent emergency braking rate is ζ, the equivalent gradient acceleration is η, the corresponding acceleration is a, the traction cut-off time is t0, the coasting time is t1, the emergency braking establishment time is t2, k1 is the emergency braking ratio coefficient of the vehicle in front, and k2 is the emergency braking ratio coefficient of the vehicle behind.

[0148] Scenario 3: The braking model of the preceding vehicle is in the emergency braking setup and emergency braking implementation phases, while the following vehicle is in the full braking phase.

[0149] f(t) = f1(t) - f2(t) + e(t)

[0150] Where f1(t) is the calculated distance when the following vehicle applies emergency braking, f2(t) is the calculated distance when the preceding vehicle applies emergency braking, and e(t) is the model error and margin.

[0151]

[0152]

[0153] e(t)=Δtv(1+ε)+(a-η)Δt 2 / 2+E

[0154] The speed of the vehicle in front is V, the speed measurement error is θ, and the equivalent emergency braking rate is B. e The equivalent slope acceleration of the vehicle in front is γ; the speed of the vehicle behind is v, the speed measurement error is ε, the equivalent emergency braking rate is ζ, the equivalent slope acceleration is η, the corresponding acceleration is a, the traction cut-off time is t0, the coasting time is t1, and the emergency braking establishment time is t2; k1 is the emergency braking ratio coefficient of the vehicle in front, and k2 is the emergency braking ratio coefficient of the vehicle behind.

[0155] As a preferred embodiment, the constraint condition for the above three cases in this invention is B. e >ζ.

[0156] Using the method of this invention, in the safety protection model based on relative braking distance calculated within a virtual coupled platoon, the leading vehicle considers the most favorable scenario, and the trailing vehicle considers the most unfavorable scenario. The braking phase of the leading vehicle does not consider the delay of the traction cut-off phase or the coasting phase delay.

[0157] Furthermore, this is reflected in the processing of train performance parameters, including treating the preceding train as if its braking system has just been calibrated, and the following train using the calculated equivalent emergency braking, taking into account the braking performance under the condition of partial loss of braking force, the braking performance of the preceding train is better than that of the following train.

[0158] Furthermore, this is reflected in the track conditions: the preceding vehicle is in the most advantageous track condition, and the following vehicle is in the most unfavorable track condition; this includes the following: when calculating the braking distance of the preceding vehicle within the effective range, only the calculated minimum downhill equivalent acceleration value is included; when the effective range only includes flat slopes and downhill slopes, the braking model is treated as flat slopes; when the effective range includes uphill slopes, the gradient acceleration is treated as uphill slopes. The gradient of the following vehicle is selected as the worst gradient value within the range from the rear of the vehicle to the target point.

[0159] The present invention further provides a storage medium that can be read by a computer or processor, wherein the storage medium stores a computer program for performing the above-described method.

[0160] Those skilled in the art will understand that the above embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-readable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It should be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create an implementation for the process. Figure 1 One or more processes and / or boxes Figure 1The computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The functions specified in one or more boxes. These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable apparatus for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0161] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A control method for safety protection within a convoy of a virtual coupled train control system, characterized in that, include: Step S11: The train calculates its position and speed information based on the electronic map, trackside equipment and speed measurement system, and calculates the equivalent braking rate during the braking phase based on the average deceleration during emergency braking. Step S12: The following vehicle obtains real-time information on the position, speed, acceleration, traction / braking status, emergency braking implementation status, and brake cylinder related parameters of the preceding vehicle; Step S13: The following vehicle plans the braking model of the preceding vehicle by judging the braking method, braking status, and braking equipment information of the preceding vehicle based on the real-time status of the preceding vehicle. When planning the braking model of the preceding vehicle, determine the braking distance of the preceding vehicle under the most favorable conditions, including: When the following vehicle calculates the most favorable braking distance for the preceding vehicle based on its current position according to the preceding vehicle's speed, acceleration, traction / braking status, and emergency braking status, it determines whether the braking method used by the train is air braking or electric braking based on the train's braking mechanism. The following train determines the braking model of the preceding train based on the current speed of the preceding train and the braking method of the preceding train, depending on the situation. The most favorable situation for the vehicle ahead includes: The first scenario: The preceding train issues an emergency braking command, and the train is in the early stage of emergency braking establishment; at this time, the braking model of the preceding train is calculated using two stages: the complete emergency braking establishment stage and the emergency braking implementation stage. The second scenario: The preceding vehicle is in a certain stage of emergency braking establishment, but the emergency braking has not yet been fully established. In this case, the relevant parameters of the brake cylinder synchronized with the preceding vehicle's status are used to accurately calculate which stage of emergency braking establishment the train is in. The braking model of the preceding vehicle adopts two stages for calculation: partial emergency braking establishment and emergency braking implementation. The third scenario: The emergency braking of the vehicle in front has been established. The braking model of the vehicle in front is calculated in two stages using emergency braking, and finally the braking distance and stopping position of the vehicle in front under the most favorable conditions are obtained. In the first scenario, the vehicle in front has a complete emergency braking initiation phase and a complete emergency braking phase: Where L is the total distance traveled by the vehicle during the emergency braking application and braking phase, and the speed measurement error is θ. This represents the speed value corresponding to the end of the second stage for the preceding vehicle. The speed value corresponding to the end of the third stage of the preceding vehicle is B, and the equivalent emergency braking rate is B. e The equivalent gradient acceleration of the vehicle in front is γ; k is the proportional coefficient for emergency braking. This marks the end of the lazy phase; This marks the end of the emergency setup phase; The speed model of the vehicle in front is: Wherein, the initial speed during the emergency braking initiation phase is the instantaneous speed at the end of the coasting phase, and V is the initial speed of the preceding vehicle. This represents the speed value corresponding to the end of the first stage for the preceding vehicle. This represents the speed value corresponding to the end of the second stage for the preceding vehicle. The speed value corresponding to the end of the third stage of the preceding vehicle is t1, the initial speed of the emergency braking stage is t2, and the equivalent emergency braking rate is B. e， The equivalent gradient acceleration of the vehicle in front is γ, and k is the proportional coefficient for emergency braking. Step S14: The following vehicle calculates the safe braking curve under the most unfavorable condition based on the real-time status of the following vehicle; Step S15: The following vehicle combines the safe braking curve of the preceding vehicle under the most favorable condition with the safe braking curve of its own vehicle under the most unfavorable condition, and calculates the tracking curve of the relative braking distance by combining the spatiotemporal collision avoidance rules.

2. The control method for safety protection within the formation of the virtual coupled train control system according to claim 1, characterized in that, In the second scenario, the vehicle in front undergoes both a partial emergency braking initiation phase and a complete emergency braking phase: in, The speed value corresponding to the end of the third stage of the preceding vehicle is given, the speed measurement error is θ, and the equivalent emergency braking rate is B. e， The time required for the train's emergency braking to fully activate is given by γ, where the equivalent gradient acceleration of the preceding train is γ, and k is the proportionality coefficient for emergency braking application. The time when the emergency begins to be applied, The timing of emergency braking is calculated based on the train's real-time braking parameters.

3. The control method for safety protection within the formation of the virtual coupled train control system according to claim 1, characterized in that, In the third scenario, the vehicle in front only has an emergency braking phase, without traction, coasting, or emergency braking initiation phases. in, The speed value corresponding to the end of the third stage of the preceding vehicle is given, the speed measurement error is θ, and the equivalent emergency braking rate is B. e The equivalent gradient acceleration of the vehicle in front is γ. The initial velocity of the emergency braking phase is the instantaneous velocity at the end of the emergency braking establishment phase, so t is taken as t2.

4. The control method for safety protection within the formation of the virtual coupled train control system according to any one of claims 1-3, characterized in that, In step S11, the virtually linked member vehicles calculate their own position and speed information based on the stored electronic map data and the speed measurement and positioning system. The equivalent emergency braking rate of the train during the braking phase is calculated from the average deceleration during emergency braking given in the vehicle performance parameters.

5. The control method for safety protection within the formation of the virtual coupled train control system according to any one of claims 1-3, characterized in that, In step S14, the following vehicle is considered to have the braking distance under the most unfavorable condition of the vehicle itself, including track conditions; information on traction cut-off delay, coasting delay and braking establishment delay in the train performance parameters; Then, the braking distance of the rear vehicle at all stages is calculated based on the IEEE 1474 safety braking model.

6. A storage medium capable of being read by a computer or processor, characterized in that, The storage medium stores a computer program for executing any one of the methods of claims 1-5.

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