A method and device for safety protection in a virtual hitched platoon and a storage medium

Abstract

The application discloses a kind of virtual coupling platoon safety protection method, device and storage medium, it includes: step S1: based on car-car communication, the state information of main car and front sequence car is obtained;Step S2: based on autonomous perception, the relative state information of main car and front sequence car is obtained;Step S3: based on the safety braking model of IEEE-1474, in combination with the actual braking characteristics of vehicle, the safety interval between trains in platoon is calculated using target-based safety braking model;Step S4: the actual interval of train in platoon is judged by logic, dynamically adjusted, and output control command.The device and storage medium are both based on the above method.The application has the advantages of simple principle, can improve the safety between trains in platoon, can improve the operation efficiency of platoon train, etc.

Description

Technical Field

[0001] This invention mainly relates to the field of virtual linkage technology, specifically a method, device, and storage medium for security protection within a virtual linkage formation. Background Technology

[0002] As the scale of transportation lines continues to expand and passenger flow increases, the contradiction between the supply of transportation capacity and the demand for passenger flow is becoming more prominent on some lines or in some areas. Pain points in operation scenarios such as tidal passenger flow, shared lines, and express trains with large stops are becoming increasingly apparent.

[0003] Currently, most transportation lines operate on single-line trains with fixed formations, and the control system operates at fixed intervals. This makes it difficult to meet the demand for different transport capacities by flexibly adjusting the number of trains, resulting in insufficient transport capacity on some lines and sections, and wasted transport capacity on others.

[0004] To address these issues, virtual coupling technology has emerged. Virtual coupling refers to the use of wireless communication and proactive sensing to acquire collaborative sensing messages between adjacent trains, breaking down existing block restrictions and enabling car-to-car coupling without physical couplers. Trains can dynamically change their configuration during operation, flexibly configuring formations based on passenger flow and adapting to different sections and time periods, thus better accommodating the temporal and spatial distribution of passenger traffic. Virtual coupling will construct dynamic and flexible train formations based on passenger flow changes, enabling multi-car collaborative control operation under intelligent scheduling. Virtual coupling has become an industry-recognized innovative development direction for future train operation control systems.

[0005] The fundamental purpose of urban rail transit signaling systems is to control the safe and efficient operation of trains. Therefore, virtual train coupling systems inevitably need to address the issues of "safety" and "efficiency." How to ensure the safety of trains within a virtual train coupling platoon, and how to make the virtual train coupling platoon operate more efficiently and improve the line's throughput capacity, have all become technical challenges and hot topics to be solved. Summary of the Invention

[0006] 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 method, device and storage medium for virtual coupling convoy safety protection that is simple in principle, can improve the safety between trains in the convoy and can improve the convoy operation efficiency.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] A method for security protection within a virtual linked fleet, comprising:

[0009] Step S1: Based on vehicle-to-vehicle communication, obtain the status information of the master vehicle and the preceding vehicles;

[0010] By utilizing point-to-point communication between vehicles within a virtual trailer platoon, the slave vehicles within the virtual trailer platoon can obtain the status information of the vehicle in front of them in real time, as well as the status information of the master vehicle of the virtual trailer platoon in real time.

[0011] Step S2: Based on autonomous perception, obtain the relative state information of the master vehicle and the preceding vehicles;

[0012] By utilizing autonomous sensing technology, the slave vehicles in the virtual convoy can obtain the relative status information of the vehicle in front of them in real time.

[0013] Step S3: Based on the IEEE-1474 safety braking model and combined with the actual braking characteristics of the vehicles, the target-based safety braking model is used to calculate the safe separation between trains in the formation.

[0014] Step S4: Logically determine the actual interval between trains in the formation, make dynamic adjustments, and output control commands.

[0015] As a further improvement to the method of the present invention: point-to-point communication is established between adjacent trains in the virtual coupling formation, the master train in the virtual coupling formation broadcasts the overall formation information to the slave trains, and the slave trains report the slave train information to the train in front of them or the master train.

[0016] As a further improvement to the method of the present invention: the overall formation information includes one or more of the following: formation train number, trackside resources applied for by the formation, formation status, formation integrity, and main vehicle characteristic parameters.

[0017] As a further improvement to the method of the present invention: the vehicle information includes vehicle characteristic parameters, which include one or more of the following: vehicle speed, position, acceleration, braking rate, and integrity.

[0018] As a further improvement to the method of the present invention: in step S3, the calculation of the safety interval is performed by the virtual coupling safety protection logic of the slave vehicle in the target-based safety braking model; the process of the virtual coupling safety protection logic includes:

[0019] Step S301: Based on the status information of the master vehicle and the preceding vehicle obtained from T2T communication and autonomous perception module, the slave vehicle calculates the safe braking distance, position and speed of its master vehicle or the preceding vehicle under the "most favorable condition";

[0020] Step S302: Calculate the safe braking distance under the "most unfavorable condition" based on the vehicle's safety braking model as specified in the IEEE 1474.1 standard;

[0021] Step S303: The difference between the safe braking distance of the lead vehicle or preceding vehicle under the "most favorable condition" and the safe braking distance of the following vehicle under the "most unfavorable condition" is the minimum safe separation of the current formation;

[0022] Step S304: Based on continuous and periodic calculations, when the actual distance exceeds the relative safe distance, the slave vehicle reduces its speed or accelerates to correct its position, and follows the master vehicle or the preceding vehicle at a safe interval; if it is too far from the preceding vehicle, the distance is reduced, and the slave vehicle accelerates to pull. 。

[0023] As a further improvement to the method of the present invention: In step S302, upon receiving an emergency braking command from the main train or the preceding train, the following train fully considers the time from the change of traction status of the train to the actual effectiveness of the emergency braking, the communication delay between the preceding and following trains, the speed measurement error of the train, and the initial positioning error, in order to form a control.

[0024] As a further improvement to the method of the present invention: In the target-based safety braking model, the safety braking decision for the main train or the preceding train is made according to the segmented and case-specific train speed values ​​as follows:

[0025] (a) Train speed is higher than T and not in the braking phase: If an emergency braking command is received, the safety braking model considers segment D + segment E; the T value is the speed threshold for the train to switch from electric braking to air braking, which is determined according to the actual train characteristics.

[0026] (b) When the train speed is higher than T and it is in the braking phase, there are three possible scenarios:

[0027] (b1) If an emergency braking command is received and the vehicle has not yet applied the air brakes, the safety braking model considers segment D + segment E.

[0028] (b2) If an emergency braking command is received and the vehicle's air brakes have not yet been fully established, the safety braking model considers part of segment D + segment E.

[0029] (b3) If an emergency braking command is received and the vehicle's air brakes are fully engaged, the safety braking model only considers segment E.

[0030] (c) Train speed below T value: Regardless of whether the vehicle is in the braking phase, the safe braking model considers section D + section E. 。

[0031] As a further improvement to the method of the present invention: In the target-based safety braking model, after receiving an emergency braking command from the master vehicle or the preceding vehicle, the slave vehicle adopts a slave vehicle safety braking decision:

[0032] (a) Using a combination of serial and parallel structures, after receiving an emergency braking command from the signal system, the train vehicle implements traction blocking and emergency braking establishment in parallel.

[0033] (b) Traction cut-off time decision: The time from the hard-wired output of the traction cut-off command from the signal system to the implementation of traction cut-off by the train traction system can be optimized to 80ms-120ms (the specific time depends on the actual train characteristics).

[0034] (c) The deceleration in segment D is linearly related to time as a(t) = kt - 0.1A. This formula is the relationship function between deceleration a and time t during the stage when the braking force is applied from 10% to 90%.

[0035] The present invention further provides a device for security protection within a virtual linked formation for implementing the above method, comprising:

[0036] The T2T communication module is used for real-time point-to-point communication between trains to obtain real-time status information of trains in the formation.

[0037] The autonomous perception module is used to autonomously perceive the relative state information of the preceding vehicles;

[0038] The logic processing module is used to calculate the safe interval between trains in the formation and the optimal speed.

[0039] The control output module is used to output control commands to the traction and braking systems.

[0040] 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.

[0041] Compared with the prior art, the advantages of the present invention are as follows:

[0042] 1. The method, device, and storage medium for safety protection within the virtual coupled train formation of the present invention are simple in principle, can improve the safety between trains within the formation, can improve the train operation efficiency of the formation, and improve the system reliability by integrating autonomous perception. The above-mentioned method of the present invention can fully consider the actual state and braking distance of the main train in the formation, ensure the safety within the virtual coupled train formation, and can shorten the train interval as much as possible, improve the line transportation efficiency, and promote the development of urban rail transit signal control system.

[0043] 2. The method, device and storage medium for safety protection within the virtual coupling formation of the present invention, compared with the traditional safety braking distance model, effectively shortens the train tracking distance while ensuring safety by optimizing the traction cut-off time.

[0044] 3. The method, device and storage medium for safety protection within the virtual coupled train formation of the present invention, compared with the traditional "collision with soft walls" tracking and protection method, creates a new phased processing model, which not only ensures the safety between trains within the virtual coupled train formation (avoiding collisions between trains within the formation), but also improves efficiency in all aspects. Attached Figure Description

[0045] Figure 1 This is a flowchart illustrating the method of the present invention.

[0046] Figure 2 This is a schematic diagram of the topological structure of the device of the present invention. Detailed Implementation

[0047] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] This invention proposes a method for safety protection within a virtual train coupling formation. After the virtual train coupling is completed and a virtual train coupling formation is formed, this method 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 within the virtual train coupling formation to avoid rear-end collisions.

[0049] To more clearly illustrate the content of the method of the present invention, the following technical features of virtual linked formations are first described:

[0050] 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.

[0051] From the train: The following train behind the main train in a virtual convoy.

[0052] Leading vehicle: A vehicle in front of another vehicle in a virtual trailer convoy, but not the lead vehicle. 。

[0053] 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:

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] For vehicle braking, it generally consists of electric braking and air braking. Train braking methods vary depending on the operating scenario, including electric braking, air braking, and a combination of both. Under normal circumstances, when the train speed exceeds a specified value (T, the speed threshold for switching from electric braking to air braking, which depends on the actual train characteristics), braking is achieved by electric braking. However, in abnormal situations such as skidding, the train will switch from electric braking to air braking. When the train speed is below T, braking is achieved by air braking. Emergency braking is always achieved by air braking. If the train is in an electric braking phase and receives an emergency braking command, it will disconnect the current electric braking and reapply emergency braking. Furthermore, electric braking has a shorter application time, while air braking has a longer application time.

[0059] Traditional signaling systems all adopt the safety braking model based on the IEEE 1474.1 standard. Sections A and B are the stages from when the ATP sends the traction cut-off command to when the vehicle actually cuts off the traction. Section C is the stage from 0 to 10% of the emergency braking force, which is the coasting stage of the train. Section D is the stage from when the emergency braking is applied to when the braking force is applied to 90% of the braking force. Section E is the stage when the emergency braking is applied.

[0060] like Figure 1 As shown, the method for security protection within a virtual linked formation according to the present invention includes:

[0061] Step S1: Based on vehicle-to-vehicle communication, obtain the status information of the master vehicle and the preceding vehicles;

[0062] By utilizing point-to-point communication between vehicles within a virtual trailer platoon, the slave vehicles within the virtual trailer platoon can obtain the status information of the vehicle in front of them in real time, as well as the status information of the master vehicle of the virtual trailer platoon in real time.

[0063] Step S2: Based on autonomous perception, obtain the relative state information of the master vehicle and the preceding vehicles;

[0064] By utilizing autonomous sensing technology, the slave vehicles in the virtual convoy can obtain the relative status information of the vehicle in front of them in real time.

[0065] Step S3: Based on the IEEE-1474 safety braking model and combined with the actual braking characteristics of the vehicles, the target-based safety braking model is used to calculate the safe separation between trains in the formation.

[0066] Step S4: Logically determine the actual interval between trains in the formation, make dynamic adjustments, and output control commands.

[0067] In the above method of the present invention, the present invention is based on vehicle-to-vehicle communication technology, and performs real-time point-to-point transmission of train status information between vehicles to achieve status interaction between trains and realize safety protection between trains in virtual coupling formation.

[0068] In the above method of the present invention, the present invention adopts autonomous sensing technology to obtain information such as the relative speed, relative acceleration, and relative position of the preceding trains in real time through autonomous sensing, and integrates them for safety protection between trains.

[0069] In specific application examples, point-to-point communication (the specific communication method is not limited) is established between adjacent trains in a virtual coupled train formation. The master train in the virtual coupled train formation broadcasts overall formation information to its slave trains, and the slave trains report their slave information to the train ahead of them or the master train. The overall formation information includes one or more of the following: train number, trackside resources obtained by the formation, formation status, formation integrity, and master train characteristic parameters. The slave train information includes slave train characteristic parameters, which include one or more of the following: slave train speed, position, acceleration, braking rate, and integrity.

[0070] In specific application examples, the slave vehicles in the virtual convoy use autonomous sensing modules to obtain information such as the relative speed, relative acceleration, and relative position of the vehicles in front of them.

[0071] In the above method of the present invention, in step S3, the target-based safety braking model is based on the information obtained above, and performs logical calculations and processing.

[0072] In a specific application example, the calculation of the safety interval in step S3 is performed by the virtual coupling safety protection logic of the slave vehicle in the target-based safety braking model; the process of the virtual coupling safety protection logic includes:

[0073] Step S301: Based on the status information of the master vehicle and the preceding vehicle obtained from the T2T communication and autonomous perception module, the slave vehicle calculates the safe braking distance, position and speed of its master vehicle or the preceding vehicle under the "most favorable condition"; please refer to the modeling description below for details, and perform case-by-case modeling.

[0074] Step S302: Calculate the safe braking distance under the "most unfavorable condition" based on the safe braking model specified in the IEEE 1474.1 standard.

[0075] Step S303: The difference between the safe braking distance of the lead vehicle or preceding vehicle under the "most favorable condition" and the safe braking distance of the following vehicle under the "most unfavorable condition" is the minimum safe separation of the current formation. Considering formation stability, this value can fluctuate appropriately within a fixed range.

[0076] Step S304: Based on continuous and periodic calculations, when the actual distance exceeds the relative safe distance, the slave vehicle reduces its speed or accelerates to correct its position, and follows the master vehicle or the preceding vehicle at a safe interval; if it is too far from the preceding vehicle, the distance is reduced, and the slave vehicle accelerates to pull. 。

[0077] In step S302, upon receiving an emergency braking command from the main train or the preceding train, the following train must fully consider the time from the change in traction status to the actual effectiveness of the emergency braking (the entire stage of the safety braking model), communication delays between the preceding and following trains, speed measurement errors, and initial positioning errors. Sufficient margin must be considered throughout the entire train control process to ensure safety.

[0078] The safe braking distance of the lead car or preceding car in a virtual coupled train formation is typically calculated using the safe braking model specified in the IEEE 1474.1 standard. Given the need to calculate the safe braking distance under the "most favorable condition," only segment E of the standard model is usually used. However, in reality, considering train braking characteristics, this is not the case. Therefore, this invention further proposes a model that divides the process into segments and cases based on train speed values. After fully considering the current train state and actual braking characteristics, the safe braking model for the lead car or preceding car is as follows:

[0079] (a) If the train speed is higher than T (the speed threshold for the train to switch from electric braking to air braking, which is determined according to the actual train characteristics) and is not in the braking phase: if an emergency braking command is received, the safety braking model considers the D-section + E-section.

[0080] (b) If the train speed is higher than T and it is in the braking phase, then there are three possible scenarios:

[0081] (b1) If an emergency braking command is received and the vehicle has not yet applied the air brakes, the safety braking model considers segment D + segment E.

[0082] (b2) If an emergency braking command is received and the vehicle's air brakes have not yet been fully established, the safety braking model considers part of segment D + segment E.

[0083] (b3) If an emergency braking command is received and the vehicle's air brakes are fully engaged, the safety braking model only considers segment E.

[0084] (c) Train speed below T value: Regardless of whether the vehicle is in the braking phase, the safe braking model considers section D + section E. 。

[0085] After receiving an emergency braking command from the master train or the preceding train, the slave train must fully consider the time from the change in traction status to the actual effectiveness of the emergency braking (completing all stages of the safety braking model), the communication delay between the master and slave trains, the train's speed measurement error, and the initial positioning error. The entire train control process should fully consider safety margins to ensure safety.

[0086] Traditional signaling systems all adopt the safety braking model based on the IEEE 1474.1 standard. Sections A and B are the stages from when the ATP sends the traction cut-off command to when the vehicle actually cuts off the traction. Section C is the stage from 0 to 10% of the emergency braking force, which is the coasting stage of the train. Section D is the stage from when the emergency braking is applied to when the braking force is applied to 90% of the braking force. Section E is the stage when the emergency braking is applied.

[0087] Since signaling system manufacturers lack understanding of vehicle braking systems, they typically calculate safe braking distances sequentially using five segments: A, B, C, D, and E. To simplify processing, segments A and B are often combined into an acceleration segment, and segments C and D into a coasting segment. This approach fails to accurately reflect train characteristics; it merely ensures safety by increasing the safe braking distance and reducing operational efficiency.

[0088] Therefore, this invention further proposes an optimized safety braking model that fully considers the actual characteristics of the train.

[0089] (a) Optimize the serial structure and change it to partial parallelism. That is, after the train receives the emergency braking command from the signal system, it implements traction blocking and emergency braking establishment in parallel;

[0090] (b) Optimize traction cut-off time. The time from the hard-wired output of the traction cut-off command from the signaling system to the implementation of traction cut-off by the train traction system (the traction cut-off relay is activated) can be optimized to 80ms-120ms (the specific time depends on the actual train characteristics). 80ms is the optimal choice. Traditional signaling system processing methods consider significant network delays and transmission / reception, failing to accurately reflect the actual train status.

[0091] (c) Optimize Section D. Currently, traditional signal system safety braking models combine sections C and D into a train inertia phase. However, in reality, section D represents the stage where the braking force of the braking system increases from 10% to 90%, meaning there is still braking force and it is not completely inertial. In this case, the deceleration of the present invention has a linear relationship with time as a(t) = kt - 0.1A (this formula is the relationship function between the deceleration a and time t during the stage where the braking force is applied from 10% to 90%).

[0092] The method described above can fully consider the actual state and braking distance of the main train in the formation, ensure the safety of the virtual coupled formation, and shorten the train interval as much as possible, improve the line transportation efficiency, and promote the development of urban rail transit signal control systems.

[0093] like Figure 2 As shown, the present invention further provides a device for security protection within a virtual linked formation used to implement the above method, comprising:

[0094] The T2T communication module is used for real-time point-to-point communication between trains to obtain real-time status information of trains in the formation.

[0095] The autonomous perception module is used to autonomously perceive the relative state information of the preceding vehicles;

[0096] The logic processing module is used to calculate the safe interval between trains in the formation and the optimal speed.

[0097] The control output module is used to output control commands to the traction and braking systems.

[0098] 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.

[0099] 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.

[0100] 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 method for security protection within a virtual linked formation, characterized in that, include: Step S1: Based on vehicle-to-vehicle communication, obtain the status information of the master vehicle and the preceding vehicles; By utilizing point-to-point communication between vehicles within a virtual trailer platoon, the slave vehicles within the virtual trailer platoon can obtain the status information of the vehicle in front of them in real time, as well as the status information of the master vehicle of the virtual trailer platoon in real time. Step S2: Based on autonomous perception, obtain the relative state information of the master vehicle and the preceding vehicles; By utilizing autonomous sensing technology, the slave vehicles in the virtual convoy can obtain the relative status information of the vehicle in front of them in real time. Step S3: Based on the IEEE-1474 safety braking model and combined with the actual braking characteristics of the vehicles, the target-based safety braking model is used to calculate the safe separation between trains in the formation. Step S4: Logically determine the actual interval between trains in the formation, make dynamic adjustments, and output control commands; In step S3, the calculation of the safety interval is performed by the vehicle virtual coupling safety protection logic in the target-based safety braking model. The process of the virtual vehicle linkage security protection logic processing includes: Step S301: Based on the status information of the master vehicle and the preceding vehicle obtained from T2T communication and autonomous perception module, the slave vehicle calculates the safe braking distance, position and speed of its master vehicle or the preceding vehicle under the "most favorable condition"; Step S302: Calculate the safe braking distance under the "most unfavorable condition" based on the vehicle's safety braking model specified in the IEEE 1474.1 standard; Step S303: The difference between the safe braking distance of the lead vehicle or preceding vehicle under the "most favorable condition" and the safe braking distance of the following vehicle under the "most unfavorable condition" is the minimum safe separation of the current formation; Step S304: Based on continuous and periodic calculations, when the actual distance exceeds the relative safe distance, the slave vehicle reduces its speed or accelerates to correct its position, and the slave vehicle follows the master vehicle or the preceding sequence vehicle at a safe interval; if it is too far from the preceding sequence vehicle, the distance should be reduced and the slave vehicle should accelerate to pull it. In the target-based safety braking model, the safety braking decision for the main train or the preceding train is made according to the segmented and case-specific train speed values ​​as follows: (a) Train speed is higher than T and not in the braking phase: If an emergency braking command is received, the safety braking model considers segment D + segment E; the T value is the speed threshold for the train to switch from electric braking to air braking; (b) When the train speed is higher than T and it is in the braking phase, there are three possible scenarios: (b1) If an emergency braking order is received and the vehicle has not yet applied the air brakes, the safety braking model considers segment D + segment E; (b2) If an emergency braking command is received and the vehicle's air brakes have not yet been fully established, the safety braking model considers part of segment D + segment E. (b3) If an emergency braking command is received and the vehicle's air brakes are fully engaged, the safety braking model only considers segment E; (c) Train speed is below T value: Regardless of whether the vehicle is in the braking phase, the safety braking model considers the D section + E section.

2. The method for security protection within a virtual linked formation according to claim 1, characterized in that, Point-to-point communication is established between adjacent trains in the virtual coupling formation. The master train in the virtual coupling formation broadcasts the overall formation information to the slave trains, and the slave trains report their information to the train in front of them or the master train.

3. The method for security protection within a virtual linked formation according to claim 2, characterized in that, The overall formation information includes one or more of the following: formation train number, trackside resources applied for by the formation, formation status, formation integrity, and main vehicle characteristic parameters.

4. The method for security protection within a virtual linked formation according to claim 2, characterized in that, The vehicle information includes vehicle characteristic parameters, which include one or more of the following: vehicle speed, position, acceleration, braking rate, and integrity.

5. The method for security protection within a virtual linked formation according to claim 1, characterized in that, In step S302, upon receiving an emergency braking command from the main train or the preceding train, the following train fully considers the time from the change in traction status of the train to the actual effectiveness of the emergency braking, the communication delay between the preceding and following trains, the speed measurement error of the train, and the initial positioning error, in order to form a control mechanism.

6. The method for security protection within a virtual linked formation according to claim 1, characterized in that, In the target-based safety braking model, after receiving an emergency braking command from the master vehicle or the preceding vehicle, the slave vehicle makes a safety braking decision: (a) Using a combination of serial and parallel structures, after receiving an emergency braking command from the signal system, the train vehicles implement traction blocking and emergency braking establishment in parallel; (b) Traction cut-off time decision: The time from the hard-wired output of the traction cut-off command from the signal system to the implementation of traction cut-off by the train traction system is optimized to 80ms-120ms; (c) The deceleration in segment D is linearly related to time. This formula is a function relating the deceleration 'a' to time 't' during the braking force application phase from 10% to 90%.

7. A device for implementing the method of any one of claims 1-6 for security protection within a virtual linked formation, characterized in that, include: The T2T communication module is used for real-time point-to-point communication between trains to obtain real-time status information of trains in the formation. The autonomous perception module is used to autonomously perceive the relative state information of the preceding vehicles; The logic processing module is used to calculate the safe interval between trains in the formation and the optimal speed. The control output module is used to output control commands to the traction and braking systems.

8. 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 1-6.

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