Space-time coordinated collision avoidance method for heavy-load train group operation considering air brake delay

Abstract

The present invention discloses a space-time coordinated collision avoidance method for heavy-load train group operation considering air brake delay. The real-time absolute braking distance including the speed-mileage-time dynamic change characteristics is calculated by collecting the position and speed information of each train in the group in real time. Then, space and time collision avoidance detection is performed according to whether the train spacing is greater than zero, and the following distance is corrected according to the detection result. That is, the changing relationship between the spatial relative position and the absolute braking time is considered, and the actual relative position and running speed of the train before braking are dynamically adjusted according to the collision avoidance detection result, so that the train spacing is always greater than zero. The present invention establishes a universal space-time coordinated collision avoidance protection method for heterogeneous heavy-load train group operation considering air brake delay.

Description

Technical Field

[0001] The invention belongs to the technical field of rail transit, and in particular relates to a space-time coordinated collision avoidance method for heavy-load train group operation taking into account air brake delay. Background Art

[0002] The increase in demand for railway transportation has significantly promoted the progress of train operation control technology. Virtual coupling, group operation and other advanced communication technologies based on shortening the headway to improve transportation capacity have become highly anticipated representative technologies. These advanced technologies have long been the focus of attention in the passenger transportation field with short formation, high mobility and good service environment such as subways and high-speed railways. In recent years, their importance in the field of heavy-duty railway freight has gradually been recognized, and large-scale experimental research has also been carried out simultaneously.

[0003] Collision avoidance is the core function of the train operation control system. In the group operation mode, the safety distance between adjacent trains is compressed to the relative braking distance. Existing studies focusing on passenger transport generally believe that as long as the head of the rear train does not exceed the tail of the front train after stopping and a certain safety margin can be retained, it can be judged as able to avoid collision. Obviously, the extremely low delay and extremely strong maneuverability ensure that this target-distance-based collision avoidance protection method that only focuses on the starting and ending positions of the train is correct and reasonable. In contrast, air brake delay is a typical attribute inherent in heavy-duty trains, which directly affects the response time and braking distance of train braking. In heterogeneous heavy-duty train groups, the difference in braking performance between different trains will lead to delay accumulation, resulting in a special phenomenon, that is, it can be judged as able to avoid collision only from the starting and ending positions of the trains, but in fact, they have already collided during the braking process. This result makes the traditional collision avoidance protection method based on target-distance challenged in the operation control of heterogeneous heavy-duty train groups. Considering the air brake delay attribute of heavy-duty trains, it becomes a basic requirement to establish a space-time coordinated collision avoidance protection method.

[0004] Existing studies on the air brake delay of heavy-haul trains generally focus on the control of single trains. Representative research contents include: synchronous control technology of 20,000-ton long-haul combined trains considering air brake delay, electronically controlled air brake (ECP) technology of heavy-haul trains, air brake application strategy on long and long slopes, the influence of air brake delay on the longitudinal dynamics of heavy-haul trains, and research on automatic driving technology of heavy-haul trains based on refined air brake models. The common feature of these studies is that they expect to apply more reasonable control strategies such as electronically controlled air brakes and introduce more advanced auxiliary equipment such as controllable tails to reduce air brake delays to achieve stable control of single trains. Group operation refers to a high-density transportation organization mode based on relative braking distances between units using 5,000-ton or 10,000-ton heavy-haul trains as basic units through vehicle-to-vehicle communication. Its basic attribute of containing multiple train units causes air brake delays to accumulate within the group, especially when heterogeneous trains form a group, the difference in air brakes will be greater, which directly affects the collision avoidance safety of shorter distance tracking operation based on relative braking distances within the group. At present, there is very little research on the collision avoidance protection method for heterogeneous heavy-load trains taking into account air brake delay in group operation mode. This patent is guided by the urgent needs of engineering experiments and practical applications, and designs a space-time coordinated collision avoidance protection method for heterogeneous heavy-load train group operation taking into account air brake delay, in order to provide theoretical guidance and technical support for improving the operating efficiency, safety level and emergency response level of heavy-load train groups. Summary of the invention

[0005] In order to overcome the above-mentioned deficiencies, the inventors of the present invention have continuously reformed and innovated through long-term exploration and attempts, multiple experiments and efforts, and proposed a space-time coordinated collision avoidance method for heavy-load train group operation taking into account air brake delay. This solves the key problem that the existing traditional collision avoidance protection methods based on the starting and ending positions of trains and based on target-distance cannot fully achieve collision avoidance protection when heterogeneous heavy-load train groups with significant differences in air brake delays are running. This establishes a universal space-time coordinated collision avoidance protection method for heterogeneous heavy-load train group operation taking into account air brake delay.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is to provide a space-time coordinated collision avoidance method for heavy-load train group operation taking into account air brake delay. The steps include:

[0007] S1: Status information collection: collect the information about the position and speed of each train in the group in real time, and send the collected position and speed information of the front and rear adjacent trains in the group to the on-board computer of the rear train synchronously;

[0008] S2: Real-time absolute braking distance calculation: The onboard computer of the rear train calculates the real-time absolute braking distances of the front and rear trains including the dynamic change characteristics of speed-mileage-time based on the received position and speed information of the two trains, taking into account the air braking delay and the dynamic changes of mileage and time during the train braking process. The final real-time absolute braking distance includes the dynamic change characteristics of speed-mileage-time.

[0009] S3: Collision avoidance detection: Collision detection is performed based on whether the train spacing is greater than zero. The train spacing is equal to the real-time absolute braking distance of the front vehicle minus the real-time absolute braking distance of the rear vehicle minus the length of the front vehicle minus the additional safety margin. Collision avoidance detection is carried out from the following two aspects:

[0010] S3.1 Spatial collision avoidance detection: Based on the speed-mileage change relationship during the braking process of the front and rear trains, determine whether the train spacing between the two adjacent trains at the braking stop position is greater than zero. If it is greater than zero, perform time collision avoidance detection, otherwise perform following distance correction;

[0011] S3.2 Time collision avoidance detection: Based on the speed-time variation relationship during the braking process of the front and rear trains, determine whether the train spacing is greater than zero in the entire time range from the start of braking to the completion of braking. If it is greater than zero, it is determined that space-time coordinated collision avoidance can be achieved, otherwise the following distance is corrected;

[0012] S4: Following distance correction: Considering the changing relationship between the spatial relative position and the absolute braking time, the actual relative position and running speed of the train before braking are dynamically adjusted according to the collision avoidance detection results, so that the train spacing is always greater than zero; the adjustment means are:

[0013] When the distance in the spatial collision avoidance detection is not greater than zero, collision avoidance is achieved by increasing the train following distance before braking in advance; when the distance in the temporal collision avoidance detection is not greater than zero, collision avoidance is achieved by reducing the running speed of the rear vehicle before braking in advance.

[0014] According to the space-time coordinated collision avoidance method for heavy-load train groups taking into account air brake delay described in the present invention, a further preferred technical solution is: in step S1, the information on the position and speed of the train comes from the on-board train automatic protection system equipment.

[0015] According to the space-time coordinated collision avoidance method for heavy-loaded train groups taking into account air brake delay described in the present invention, a further preferred technical solution is: in step S2, the calculation of the air brake delay needs to take into account the number of train sets before and after the train, the brake type, the train pipe set pressure and the train pipe decompression. The number of train sets is updated manually, the brake type and the train pipe set pressure data are obtained according to the actual air brake device of the train, and the train pipe decompression is taken as 60kPa or 100kPa based on empirical values.

[0016] According to the space-time coordinated collision avoidance method for heavy-loaded train groups taking into account air braking delay described in the present invention, a further preferred technical solution is: in step S4, the method for determining the increase in the train following distance is: in the speed-mileage-time dynamic change curve of the real-time absolute braking distance, taking the speed-mileage profile projection as a reference, by translating the speed-mileage curve of the rear vehicle in the direction of decreasing mileage to ensure that the train spacing is greater than zero, and the absolute value of the change in mileage value before and after the translation is the increase in the relative position in the train following time distance.

[0017] According to the space-time coordinated collision avoidance method for heavy-loaded train groups taking into account air braking delay described in the present invention, a further preferred technical solution is: in step S4, the method for determining the reduction in the running speed of the rear vehicle is: in the speed-mileage-time dynamic change curve of the real-time absolute braking distance, taking the speed-time profile projection as a reference, by translating the speed-mileage curve of the rear vehicle along the speed reduction direction to ensure that the train spacing is greater than zero, the absolute value of the speed value change before and after the translation is the reduction in the running speed in the train following time distance.

[0018] Compared with the prior art, the technical solution of the present invention has the following advantages / benefits:

[0019] 1. A space-time coordinated collision avoidance protection method for heterogeneous heavy-load train groups considering air brake delay is proposed. This overcomes the technical defect that the traditional target-distance-based collision avoidance protection method cannot fully achieve collision avoidance protection when heterogeneous heavy-load train groups are running. A universal space-time coordinated collision avoidance protection method for heterogeneous heavy-load train groups considering air brake delay is established.

[0020] 2. The basic data required by this method is more general and easier to obtain, the calculation process is simpler, and the correction method is more intuitive, which significantly reduces the cost of measurement equipment, labor cost and operation and maintenance cost.

[0021] 3. It can calculate and evaluate in real time whether the train can achieve space-time coordinated collision avoidance protection, and correct the train spacing and running speed based on the calculation and evaluation results, thereby improving the collision avoidance safety of train group operation at a lower cost.

[0022] 4. Directly obtain basic data information from the on-board ATP, which is more general and universal, and is applicable to many actual scenarios such as high-speed railways, heavy-load freight railways, urban rail transit, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 It is a flow chart of the space-time coordinated collision avoidance method for heavy-load train group operation taking into account air brake delay of the present invention.

[0025] Figure 2 This is an actual line data diagram of Example 2 of the present invention.

[0026] Figure 3 This is a train speed diagram of embodiment 2 of the present invention.

[0027] Figure 4 This is a real-time absolute braking distance diagram of embodiment 2 of the present invention.

[0028] Figure 5 This is a typical result diagram of a collision occurring in the spatial collision avoidance detection of Example 2 of the present invention.

[0029] Figure 6 This is a typical result diagram of a collision occurring in the time collision avoidance detection in Example 2 of the present invention.

[0030] Figure 7 This is a diagram showing the results of the space-time coordinated collision avoidance analysis of the front and rear train braking after the correction of the following distance in Example 2 of the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention.

[0032] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and thus, once an item is defined in one drawing, it may not be further defined or explained in the subsequent drawings.

[0033] Embodiment 1:

[0034] like Figure 1As shown, a method for space-time coordinated collision avoidance of a heavy-load train group operation considering air brake delay is provided. The steps include:

[0035] S1: Status information collection: collect the information about the train position and speed of each train in the group in real time, and send the collected position and speed information of the front and rear adjacent trains in the group to the on-board computer of the rear train synchronously. The information of train position and speed comes from the on-board train automatic protection system equipment (train on-board ATP;

[0036] S2: Real-time absolute braking distance calculation: The onboard computer of the rear train calculates the real-time absolute braking distances of the front and rear trains based on the received position and speed information of the two trains, taking into account the air brake delay. The real-time absolute braking distance calculation takes into account the dynamic changes of mileage and time during the train braking process. The final real-time absolute braking distance contains the dynamic change characteristics of speed-mileage-time. The calculation of air brake delay needs to consider the number of marshalings, brake machine type, train pipe set pressure and train pipe decompression of the front and rear trains. The number of marshalings is updated manually, and the brake machine type and train pipe set pressure data are obtained according to the actual air brake device of the train. The train pipe decompression is taken as 60kPa or 100kPa based on the empirical value.

[0037] S3: Collision avoidance detection: Collision detection is performed based on whether the train spacing is greater than zero. The train spacing is equal to the real-time absolute braking distance of the front vehicle minus the real-time absolute braking distance of the rear vehicle minus the length of the front vehicle minus the additional safety margin (train spacing = real-time absolute braking distance of the front vehicle - real-time absolute braking distance of the rear vehicle - length of the front vehicle - additional safety margin). Collision avoidance detection is carried out from the following two aspects:

[0038] S3.1 Spatial collision avoidance detection: Based on the speed-mileage change relationship during the braking process of the front and rear trains, determine whether the distance between the two adjacent trains at the braking and stopping positions is greater than zero. If it is greater than zero, perform time collision avoidance detection, otherwise perform following distance correction; S3.2 Temporal collision avoidance detection: Based on the speed-time change relationship during the braking process of the front and rear trains, determine whether the distance between the two trains is greater than zero in the entire time range from the start of braking to the completion of braking. If it is greater than zero, it is determined that space-time coordinated collision avoidance can be achieved, otherwise perform following distance correction;

[0039] S4: Following distance correction: Considering the changing relationship between the spatial relative position and the absolute braking time, the actual relative position and running speed of the train before braking are dynamically adjusted according to the collision avoidance detection results, so that the train spacing is always greater than zero; the adjustment means are:

[0040] When the spacing in the spatial collision avoidance detection is not greater than zero, collision avoidance is achieved by increasing the train following distance before braking in advance. The method for determining the increase in the train following distance is as follows: in the speed-mileage-time dynamic change curve of the real-time absolute braking distance, the speed-mileage profile projection is used as a reference, and the speed-mileage curve of the rear vehicle is translated in the direction of decreasing mileage to ensure that the train spacing is greater than zero. The absolute value of the change in mileage value before and after the translation is the increase in the relative position in the train following distance; When the spacing in the temporal collision avoidance detection is not greater than zero, collision avoidance is achieved by reducing the running speed of the rear vehicle before braking in advance. The method for determining the reduction in the running speed of the rear vehicle is as follows: in the speed-mileage-time dynamic change curve of the real-time absolute braking distance, the speed-time profile projection is used as a reference, and the speed-mileage curve of the rear vehicle is translated in the direction of decreasing speed to ensure that the train spacing is greater than zero. The absolute value of the change in speed value before and after the translation is the reduction in the running speed in the train following distance.

[0041] Embodiment 2:

[0042] Take the actual line and train data of China's Baoshen Railway as an example:

[0043] S1: Status information collection: Real-time collection of train position and speed information from the onboard ATP (Automatic Train Protection System) equipment of each train in the group, and synchronously send the collected position and speed information of the front and rear adjacent trains in the group to the onboard computer of the rear train. Actual line data such as Figure 2 As shown, the train running speed is Figure 3 shown.

[0044] S2: Real-time absolute braking distance calculation: The onboard computer of the rear train calculates the real-time absolute braking distance of the front and rear trains based on the received position and speed information of the two trains, taking into account the air brake delay. Among them: (1) The calculation of air brake delay needs to take into account the number of trains in front and behind, the type of brake, the train pipe set pressure and the train pipe decompression. The number of trains is updated manually, the brake type and the train pipe set pressure data are obtained based on the actual air brake device of the train, and the train pipe decompression is an empirical value, usually 60kPa or 100kPa; (2) When calculating the real-time absolute braking distance, it is necessary to consider the dynamic changes of mileage and time during the train braking process. The final real-time absolute braking distance includes the dynamic change characteristics of speed-mileage-time. Figure 4 The real-time absolute braking distance of a 5000-ton heavy-load train is given when the train pipe constant pressure is 500 kPa and the train pipe reduced pressure is 60 kPa.

[0045] S3: Collision avoidance detection: Collision detection is performed based on whether the distance between trains is greater than zero. The distance between trains is equal to the real-time absolute braking distance of the front train minus the real-time absolute braking distance of the rear train minus the length of the front train minus the additional safety margin. Collision avoidance detection is carried out from the following two aspects: (1) Spatial collision avoidance detection: Based on the speed-mileage change relationship during the braking process of the front and rear trains, it is determined whether the distance between trains at the braking and stopping positions of the two adjacent trains is greater than zero. If it is greater than zero, a time collision avoidance detection is performed, otherwise a following distance correction is performed; (2) Temporal collision avoidance detection: Based on the speed-time change relationship during the braking process of the front and rear trains, it is determined whether the distance between trains is greater than zero in the entire time range from the start of braking to the completion of braking. If it is greater than zero, it is determined that space-time coordinated collision avoidance can be achieved, otherwise a following distance correction is performed.

[0046] Figure 5 The typical representative results of collisions in space collision avoidance detection are given. Figure 6 Typical representative results are given that satisfy spatial collision avoidance detection but collision occurs in temporal collision avoidance detection.

[0047] S4: Following distance correction: Following distance correction refers to considering the changing relationship between the spatial relative position and the absolute braking time, and dynamically adjusting the actual relative position and running speed of the train before braking based on the collision avoidance detection results, so that the train spacing is always greater than zero. (1) When the distance in spatial collision avoidance detection is not greater than zero, collision avoidance is achieved by increasing the following distance of the train before braking in advance. The method for determining the increase in the following distance is as follows: in the speed-mileage-time dynamic change curve of the real-time absolute braking distance, the speed-mileage profile projection is used as the reference, and the speed-mileage curve of the rear vehicle is translated backward along the mileage axis (i.e., in the direction of mileage reduction) to ensure that the train distance is greater than zero. The absolute value of the mileage value change before and after the translation is the increase in the relative position in the train following distance. (2) When the distance in temporal collision avoidance detection is not greater than zero, collision avoidance is achieved by reducing the running speed of the rear vehicle before braking in advance. The method for determining the reduction in the running speed of the rear vehicle is as follows: in the speed-mileage-time dynamic change curve of the real-time absolute braking distance, the speed-time profile projection is used as the reference, and the speed-mileage curve of the rear vehicle is translated downward along the speed axis (i.e., in the direction of speed reduction) to ensure that the train distance is greater than zero. The absolute value of the speed value change before and after the translation is the reduction in the running speed in the train following distance.

[0048] Figure 7 The analysis results of space-time coordinated collision avoidance of the leading and trailing trains after correction of the following distance are given.

[0049] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0050] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0052] The above are only preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be regarded as limiting the present invention, and the protection scope of the present invention should be based on the scope defined by the claims. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A method for space-time coordinated collision avoidance of heavy-load train groups considering air brake delay, characterized in that: The steps include: S1: Status information collection: collect information about the position and speed of each train in the group in real time, and synchronously send the collected position and speed information of the front and rear adjacent trains in the group to the on-board computer of the rear vehicle; S2: Real-time absolute braking distance calculation: The on-board computer of the rear vehicle calculates the real-time absolute braking distances of the front and rear trains including the dynamic change characteristics of speed-mileage-time based on the received position and speed information of the two trains, taking into account the air braking delay and the dynamic changes of mileage and time during the train braking process. The final real-time absolute braking distance includes the dynamic change characteristics of speed-mileage-time; S3: Collision avoidance detection: perform collision detection based on whether the train spacing is greater than zero. The train spacing is equal to the real-time absolute braking distance of the front vehicle minus the real-time absolute braking distance of the rear vehicle minus the length of the front vehicle minus the additional safety margin; the collision avoidance detection is carried out from the following two aspects: S3.1 Spatial collision avoidance detection: judge whether the train spacing at the braking and stopping positions of the two adjacent trains is greater than zero based on the speed-mileage change relationship during the braking process of the front and rear trains. If it is greater than zero, perform time collision avoidance detection, otherwise perform following distance correction; S3.2 Time collision avoidance detection: judge whether the train spacing is greater than zero in the entire time range from the start of braking to the completion of braking based on the speed-time change relationship during the braking process of the front and rear trains. If it is greater than zero, it is determined that space-time coordinated collision avoidance can be achieved, otherwise the following distance is corrected; S4: Following distance correction: consider the changing relationship between the spatial relative position and the absolute time of braking, and dynamically adjust the actual relative position and running speed of the train before braking according to the collision avoidance detection results to ensure that the train spacing is always greater than zero; the adjustment method is: when the spacing is not greater than zero in the spatial collision avoidance detection, collision avoidance is achieved by increasing the train following distance before braking in advance; when the spacing is not greater than zero in the time collision avoidance detection, collision avoidance is achieved by reducing the running speed of the rear vehicle before braking in advance.

2. The space-time coordinated collision avoidance method for heavy-load train group operation considering air brake delay according to claim 1 is characterized in that: In step S1, the information of train position and speed comes from the on-board automatic train protection system equipment.

3. The space-time coordinated collision avoidance method for heavy-load train group operation considering air brake delay according to claim 1, characterized in that: In step S2, the calculation of air brake delay needs to take into account the number of train sets, brake type, train pipe set pressure and train pipe decompression of the front and rear trains. The number of train sets is updated manually, and the brake type and train pipe set pressure data are obtained based on the actual air brake device of the train. The train pipe decompression is taken as 60kPa or 100kPa based on empirical values.

4. The space-time coordinated collision avoidance method for heavy-load train group operation considering air brake delay according to claim 1, characterized in that: In step S4, the method for determining the increase in the train following distance is: in the speed-mileage-time dynamic change curve of the real-time absolute braking distance, taking the speed-mileage profile projection as the reference, by translating the speed-mileage curve of the rear vehicle in the direction of decreasing mileage to ensure that the train spacing is greater than zero, the absolute value of the change in mileage value before and after the translation is the increase in the relative position in the train following time distance.

5. The space-time coordinated collision avoidance method for heavy-load train group operation considering air brake delay according to claim 1, characterized in that: In step S4, the method for determining the amount of reduction in the running speed of the rear vehicle is as follows: in the speed-mileage-time dynamic change curve of the real-time absolute braking distance, the speed-mileage curve of the rear vehicle is translated along the speed reduction direction based on the speed-time profile projection to ensure that the train spacing is greater than zero. The absolute value of the speed change before and after the translation is the amount of reduction in the running speed during the train following distance.

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