Freight train long and large downhill cyclic braking method and device and medium

Abstract

The invention discloses a freight train long and large downhill circular braking method and device and a medium, and the method comprises the specific steps: determining a long and large downhill section, and determining the safety limiting speed of a train; determining the starting point of the braking interval and the entrance speed of the starting point, and determining the condition that the train leaves the braking interval after braking is cancelled; according to the starting point of the braking interval and the entrance speed of the starting point, the braking starting moment of the train is determined, and the train is braked at the braking starting moment; judging whether the speed of the braked train meets the running speed requirement of the train or not; when the train speed meets the train running speed requirement, whether the train speed meets the condition that braking is cancelled and the train runs out of the braking section or not is judged; when the speed of the train does not meet the condition that the train runs out of the braking section after braking is cancelled, whether the train needs to be braked or cancelled is judged according to the safety limiting speed; and the judgment process of the train speed is repeated until the train speed meets the condition that the train runs out of the braking section after braking is cancelled.

Description

Technical Field

[0001] The invention relates to the field of rail transportation, and in particular to a method, equipment and medium for cyclic braking of a freight train downhill. Background Art

[0002] When a heavy-loaded train is running on a long downhill slope, it will be affected by the gravity component and its speed will gradually increase. To ensure safety, the Automatic Train Operation (ATO) system needs to control the speed in a timely and reasonable manner during freight transportation. If the train brakes are not timely enough, it may cause safety hazards such as train speeding or hook breakage; conversely, if the braking time is too long, the braking force will gradually weaken, and there is a risk of brake shoe overheating. At the same time, too long braking time will also affect operating efficiency.

[0003] In the long downhill scenario, heavy-loaded trains usually adopt a cyclic braking strategy, but the timing of applying brakes and relieving them often depends on the driving experience summarized in the past (i.e., brake spectrum), and there is a lack of automatic braking control methods based on dynamic model-related models. Therefore, there is currently a lack of a method that can support automatic driving of heavy-loaded trains on long downhill slopes. Summary of the invention

[0004] The purpose of the present invention is to provide a method, equipment and medium for cyclic braking of freight trains on a long downhill slope, so as to realize automatic driving of the cyclic braking-coasting process of the train on a long downhill section, improve the accuracy and real-time performance of the "cyclic braking-coasting" planning strategy, and effectively avoid the risk of train speeding.

[0005] In order to achieve the above object, in a first aspect, the present invention provides a method for cyclically braking a freight train on a long downhill slope, the specific steps comprising:

[0006] Step S1, determining a long downhill section and determining a safe speed limit of the train;

[0007] Step S2, determining the starting point of the braking section and the entrance speed of the starting point, and determining the conditions for the train to cancel the braking and exit the braking section;

[0008] Step S3, determining the time when the train starts braking according to the starting point of the braking section and the entrance speed of the starting point, and the train brakes at the time when braking starts;

[0009] Step S4, judging whether the speed of the train after braking meets the train running speed requirement; when the train speed meets the train running speed requirement, judging whether the train speed meets the condition of cancelling the braking and leaving the braking section; when the train speed does not meet the condition of cancelling the braking and leaving the braking section, the coasting model is built through the train speed point after braking, and judging whether the train needs to brake or cancel the brake according to the safety limit speed;

[0010] Repeat step S4 until the speed of the train meets the condition for canceling the brakes and leaving the braking section.

[0011] Optionally, in step S2, the method for determining the starting point of the braking interval and the entrance speed of the starting point includes:

[0012] The distance and speed point of the train when the train starts braking according to the brake spectrum is taken as the starting point of the original braking interval. The train speed corresponding to the starting point of the original braking interval is the initial speed v of the original starting point. 0 ;

[0013] According to the equivalent slope conditions of the line, calculate the train entrance speed v at the original starting point 0 The coasting time Δt required for the train to coast to the safety limit speed 0 , and plot the train's coasting time Δt 0 The first coasting curve in the embodiment; wherein the safety limit speed is the maximum safety speed of the train set according to the long downhill section;

[0014] By comparing the train braking time t 加压 and coasting time Δt 0 , determine whether it is necessary to correct the starting point of the braking interval and the entrance speed of the starting point; when the braking time is less than the coasting time, there is no need to correct the braking interval, the starting point of the braking interval is the original braking interval starting point, and the entrance speed v of the starting point is 1 is the original starting point entrance velocity v 0 .

[0015] Optionally, in step S2, the method for determining the starting point of the braking interval and the entrance speed of the starting point further includes:

[0016] When the braking time t 加压 Greater than or equal to the coasting time Δt 0 When the train needs to brake in advance, the braking section needs to be corrected, and the starting point and the entrance speed of the braking section need to be corrected;

[0017] Methods for correcting the starting point and the entrance speed of the braking interval include:

[0018] The train braking time is at least (t 加压 -Δt 0 ); according to the time of early braking of the train, the first coasting curve is extended in the opposite direction of the train running, and a second coasting curve corresponding to the time of early braking of the train is drawn; the left end point of the second coasting curve is taken as the starting point of the train braking section, and the train speed v corresponding to this point 0 ' is the inlet velocity v at the starting point 1 .

[0019] Optionally, in step S2, the method for determining the condition for the train to cancel braking and exit the braking section includes:

[0020] The final speed of the train after the long downhill section is taken as the speed v at the end of the braking section. 2 and at the speed v at the end of the braking interval 2 Perform differential calculation in the opposite direction of train movement and plot the speed v at the end of the braking section. 2 The terminal coasting curve is the end point; the condition for the train to cancel the brakes and leave the braking section is that the speed of the train is less than or equal to the speed corresponding to the terminal coasting curve.

[0021] Optionally, in step S3, the method for determining the time when the train starts braking includes:

[0022] The entrance speed v from the starting point of the braking zone 1 Perform differential calculation along the train running direction, draw the third coasting curve, and record the time when the train speed reaches the safety limit speed when the train runs along the third coasting curve as t 1 The time when the train starts braking is (t 1 -t 加压 ).

[0023] Optionally, in step S4, the method for determining whether the train speed meets the train running speed requirement includes:

[0024] Set the minimum relief speed for trains on long downhill sections;

[0025] When the train is at (t 1 -t 加压 ) and the braking has been maintained for the minimum braking time t 最小制动 After that, if the train speed is less than or equal to the minimum relief speed, the train will continue to brake until it stops; when the train is at (t 1 -t 加压 ) and the braking has been maintained for the minimum braking time t 最小制动 After that, if the speed of the train is greater than the minimum relief speed, the train determines whether to brake or coast based on the terminal coasting curve.

[0026] Optionally, in step S4, the method for determining whether the train speed satisfies the condition for canceling the brake and exiting the braking section includes:

[0027] The train is at (t 1 -t 加压 ) and the braking has been maintained for the minimum braking time t 最小制动After that, it is determined whether the train speed and the distance traveled at this time meet the conditions for canceling the brake and leaving the braking section, and the train is moved to the next stop (t 1 -t 加压 ) and maintain the minimum braking time t 最小制动 The time after is recorded as t 2 time;

[0028] When t 2 When the train speed at a certain moment satisfies the conditions for cancelling the brakes and exiting the braking section, the train will immediately cancel the brakes and coast out of the braking section.

[0029] Optionally, in step S4, the method for judging whether the train needs to brake or cancel the brake according to the safety limit speed includes:

[0030] When t 2 When the train speed at time t does not meet the conditions for canceling the brake and leaving the braking zone, 2 The train speed and distance at the time point are used to model the coasting, so that t 2 The train speed and distance at the time are differentiated along the train running direction to obtain (t 缓解 +t 惰行 +t 加压 ) time; where t 缓解 The time required for the train to release the brakes; t 惰行 The minimum operating mode conversion time required to be maintained as specified in the train operating regulations;

[0031] When the fourth coasting curve reaches the train's safety limit speed, the train will 2 Keep braking at all times; when the fourth coasting curve does not reach the train safety limit speed, the train 2 Immediately release the brakes and let the train coast. 2 +t 缓解 +t 惰行 ) and re-evaluate the train's position at (t 2 +t 缓解 +t 惰行 ) moment and maintain the minimum braking time t 最小制动 Check whether the speed after braking meets the conditions for canceling the braking and exiting the braking zone.

[0032] Optionally, in step 4, the method of repeatedly determining whether the train speed meets the train running speed requirement includes:

[0033] The time when the train releases the brakes each time is recorded as t i , and i>2; when the train is at (t i +t 缓解 +t 惰行) and maintain the minimum braking time t 最小制动 When the speed after the train is less than or equal to the minimum relief speed, the train will brake until the train stops. i +t 缓解 +t 惰行 ) and maintain the minimum braking time t 最小制动 When the subsequent speed is greater than the minimum relief speed, it is further determined whether the train speed meets the conditions for canceling the brakes and exiting the braking zone.

[0034] Optionally, in step 4, the method of repeatedly determining whether the train speed satisfies the condition for canceling the brake and traveling out of the braking section includes:

[0035] When (t i +t 缓解 +t 惰行 ) The train passes the minimum braking time t 最小制动 When the speed after braking meets the conditions for canceling the brake and exiting the braking section, the train cancels the brake and coasts out of the braking section; when (t i +t 缓解 +t 惰行 ) The train passes the minimum braking time t 最小制动 When the speed after braking does not meet the conditions for canceling the brake and leaving the braking zone, the train is i +t 缓解 +t 惰行 ) and maintain the minimum braking time t 最小制动 The coasting model is built based on the train speed and distance points after the coasting, and a coasting curve is drawn. It is judged whether the speed of the train along the coasting curve exceeds the safety limit speed. When the train speed exceeds the safety limit speed, the train continues to brake. When the train speed does not exceed the safety limit speed, it is repeatedly judged whether the train speed meets the conditions for canceling the brakes and moving out of the braking interval, until the train speed meets the conditions for canceling the brakes and moving out of the braking interval, so that the train coasts out of the braking interval.

[0036] Optionally, in step S1, the method for determining the long downhill section includes: a method for calculating an equivalent slope;

[0037] Methods for calculating equivalent slope include:

[0038] According to the actual line slope, the line is divided into multiple sections; multiple sampling points are evenly set in each section, and the arrival of the train head at the sampling point is used as the sampling standard to calculate the slope resistance encountered by the train at each sampling point; according to the number of sampling points in the section, the average slope resistance of the section is calculated; and according to the average slope resistance and the total mass of the train, the line section is converted into an equivalent slope section; wherein, the train slope resistance at each sampling point is the sum of the slope resistances calculated for each carriage according to the slope at which it is located when the train head arrives at the sampling point.

[0039] Optionally, in step S1, the method for calculating the safety speed limit includes:

[0040] According to the brake spectrum, the braking decompression of the train at the maximum equivalent slope in the long downhill section is obtained, and the relationship between the speed and the travel distance of the train when the train is under maximum full-train braking corresponding to the braking decompression is calculated; according to the relationship between the speed and the travel distance of the train and the protection curve, a decompression protection curve is drawn; the speed point on the decompression protection curve is the safe limit speed of the train.

[0041] Optionally, the method for drawing a protection curve includes:

[0042] The train protection curve is drawn based on the calculated slope and length of the equivalent slope section and the relationship between the speed of the train under the maximum braking commonly used for trains under the equivalent slope and the travel distance; wherein the speed point on the protection curve is the speed limit of the train.

[0043] Optionally, the safety limit speed of the train does not exceed the speed limit.

[0044] In a second aspect, the present invention provides an electronic device, comprising a processor and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, any of the methods described in the first aspect is implemented.

[0045] In a third aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed, any of the methods described in the first aspect can be implemented.

[0046] Compared with the prior art, the technical solution of the present invention has at least the following beneficial effects:

[0047] The present invention sets the minimum relief speed of the train and the terminal speed of the braking section, and uses the train coasting model to determine the starting point of the braking section, the entrance speed of the starting point, the conditions for the train to exit the braking section, and the moment when the train applies braking force in the braking section. A real-time planning algorithm is used to timely determine whether the train needs to stop, brake or coast, thereby realizing automatic driving of the train in a cyclic braking-coiling process on a long downhill section.

[0048] The present invention does not need to use an accurate train braking model, and adopts a real-time planning algorithm based on a single differential calculation to avoid a highly complex iterative optimization process, thereby making the "cyclic braking-coasting" planning strategy have higher control accuracy and real-time performance.

[0049] The "cyclic braking-coiling" strategy formulated in the present invention fully considers the high efficiency of automatic operation of trains in long downhill scenarios. By drawing a braking decompression protection curve corresponding to the long downhill section, the safe limit speed of the train during cyclic braking-coiling is limited, which effectively avoids the risk of overspeeding of the train during the long downhill process and ensures the safety of train operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 The present invention is a flow chart of the long downhill cyclic braking method for freight trains.

[0051] Figure 2 The present invention is a schematic diagram of a method for determining a starting point of a braking interval in a long downhill cyclic braking method for a freight train.

[0052] Figure 3 It is a schematic diagram of the "cyclic braking-coasting" planning strategy of the long downhill cyclic braking method for freight trains of the present invention. DETAILED DESCRIPTION

[0053] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] In the description of the present invention, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0055] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" 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; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0056] like Figure 1 As shown, the present invention provides a method for cyclic braking of a freight train on a long downhill slope, and the specific steps include:

[0057] Step 1: Identify the long downhill section, calculate the equivalent slope, and draw the protection curve.

[0058] According to the line slope conditions and the train model based on multiple particles, the actual line equivalent slope under single particle is converted to determine whether the equivalent slope meets the conditions of the long downhill section.

[0059] The long downhill section refers to a section where the line slope exceeds 6‰ and the line length is 8km or more; a section where the line slope exceeds 12‰ and the line length is 5km or more; a section where the line slope exceeds 20‰ and the line length is 2km or more.

[0060] According to the actual line slope, the line can be divided into multiple sections and their equivalent slopes can be calculated separately.

[0061] When calculating the equivalent slope, multiple sampling points are evenly set on each section that needs to be equivalent, and the arrival of the train head at the sampling point is used as the sampling standard to calculate the slope resistance of the train at each sampling point; according to the number of sampling points on the section, the average slope resistance of the section is calculated; and according to the average slope resistance and the total mass of the train, the line section is converted into an equivalent slope section. Among them, the train slope resistance at each sampling point is the sum of the slope resistance calculated for each carriage according to the slope it is on when the train head arrives at the sampling point.

[0062] According to the calculated slope and length of the equivalent slope section, determine whether the line meets the conditions of a long downhill section. When the line meets the conditions of a long downhill section, draw the train protection curve based on the relationship between the speed of the train and the travel distance under the maximum braking commonly used by the train under the equivalent slope, such as Figure 2 The Zhongyuan protection curve shows that the speed limit of the train is obtained when it moves in a long downhill section. When the train runs in the protection curve, the train will have the risk of overspeeding if it uses less braking.

[0063] At the same time, according to the brake spectrum, draw the existing speed curve of the train in the long downhill section, such as Figure 2 As shown in the Zhongyuan speed curve.

[0064] Step 2, draw a pressure reduction protection curve.

[0065] According to the brake spectrum, the braking decompression of the train at the maximum equivalent slope in the long downhill section is obtained, and the relationship between the speed and the travel distance of the train when the train is under the maximum full-train braking corresponding to the braking decompression is calculated. The decompression is the maximum braking force that the train can generate under the braking decompression, and the braking force can slow down the train.

[0066] According to the relationship between the speed and travel distance of the train and the protection curve in step 1, draw a pressure reduction protection curve, such as Figure 2 As shown in the protection curve redrawn according to the braking level, it is ensured that the speed of the train running at the decompression protection curve (i.e. the safe limit speed of the train) will not exceed the limit speed, and there is no risk of exceeding. At this time, the speed point on the decompression protection curve is called the safe limit speed.

[0067] Step 3: Determine the starting point of the braking interval and the entrance speed v at the starting point 1 .

[0068] The distance from the start of braking in the long downhill section to the exit of the long downhill section is marked as the braking interval, and the distance and speed point of the train when the train starts braking according to the brake spectrum is taken as the starting point of the original braking interval. Figure 2 The speed of the original speed curve at the starting point of the original braking interval is taken as the original starting point entrance speed v 0 .

[0069] The coasting model is used to determine whether the braking interval of the train needs to be corrected. The coasting model is a process in which the train is coasting (i.e., the train is traveling without applying braking force). The relationship between the speed and the distance traveled is calculated by differentiation, and a coasting curve can be drawn based on the relationship between the speed and the distance traveled.

[0070] According to the equivalent slope conditions of the line, calculate the train entrance speed v at the original starting point0 The coasting time Δt required for the train to coast to the safety limit speed 0 ,Right now Figure 2 In the original velocity curve, the original starting point entrance velocity v 0 Perform differential calculation from the starting point forward (i.e. the direction of train operation), draw the first coasting curve of the train, until the first coasting curve intersects with the protection curve redrawn according to the braking level, and record the time the train takes to run in the first coasting curve as the coasting time Δt 0 .

[0071] The time required from the start of braking to the time when the brake cylinder pressure of all carriages reaches the maximum value (that is, the braking force of the train reaches the maximum value) is recorded as the braking time t 加压 , by comparing the braking time t 加压 and coasting time Δt 0 The relationship between the starting point of the braking interval is further determined to complete the correction of the starting point of the braking interval and the starting point entrance speed.

[0072] When the braking time is less than the coasting time, the train can reach the maximum braking force during the coasting time, so the train can start braking during the coasting process to control the train speed not to exceed the safety limit speed. At this time, the braking interval remains unchanged, and the starting point of the train braking interval is the original braking interval starting point (i.e. Figure 2 The left end point of the first coasting curve in the figure), the inlet velocity v at the starting point 1 is the original starting point entrance velocity v 0 .

[0073] When the braking time t 加压 Greater than or equal to the coasting time Δt 0 If the train starts braking at the starting point of the original braking section during coasting, the braking force of the train does not reach the maximum value when the train speed reaches the safety limit speed, that is, the train cannot complete the braking speed control, which may cause the train speed to exceed the speed limit, causing the risk of overspeeding and causing safety hazards. Therefore, it is necessary to correct the braking section and re-determine the starting point of the braking section and the entrance speed of the starting point.

[0074] Due to the braking time t 加压 Longer, so the train should brake in advance, and the time for the train to brake in advance is at least (t 加压 -Δt 0 ), to ensure that the train can reach the maximum braking force from the beginning of braking and complete the speed control of the train within the time when its speed reaches the safety limit speed during the coasting process. Figure 2 The starting point v of the original braking section in the first coasting curve 0Perform a differential calculation backward to extend it in the opposite direction of the s axis (i.e. the opposite direction of the train running) to obtain the second coasting curve corresponding to the time of early braking of the train. At this time, the left end point of the second coasting curve is the starting point of the train braking section, and the train speed v corresponding to this point is 0 ' is the inlet velocity v at the starting point 1 ; The time required for the train to run in the first and second coasting curves is greater than or equal to the braking time t 加压 , so that the train can generate maximum braking force before the speed reaches the safety limit speed during coasting, thereby achieving speed control of the train.

[0075] Step 4, set the speed at the end point of the braking interval, and draw the end point coasting curve of the speed at the end point of the braking interval.

[0076] According to the project requirements, the final speed of the train after the long downhill section is taken as the speed v at the end of the braking section. 2 and at the speed v at the end of the braking interval 2 Perform differential calculation backward (i.e., in the opposite direction of the train's running) and draw the train's terminal coasting curve in the reverse direction along the s axis. The terminal coasting curve indicates that the final speed of the train leaving the braking zone without braking is v 2 The relationship between the speed of the train and the distance traveled.

[0077] At the same time, the train speed is less than or equal to the speed corresponding to the terminal coasting curve (that is, the train speed and distance point fall on the terminal coasting curve or below the terminal coasting curve) as a condition for the train to cancel braking and exit the braking section.

[0078] Step 5: Develop a “cyclic braking-coasting” planning strategy for the train.

[0079] According to project requirements, set the minimum relief speed v of the train in the long downhill section 缓解 , when the train speed is lower than the minimum relief speed v in the braking section due to weather or equipment failure 缓解 The train will brake until it stops and restart after stopping to ensure safe running of the train. 缓解 The train further determines whether braking or coasting is required.

[0080] like Figure 3 As shown, the entrance speed v from the starting point of the braking interval 1 Perform differential calculation forward (i.e., the direction of train operation), draw the third coasting curve along the s-axis direction, and determine the relationship between the third coasting curve and the decompression protection curve (i.e. Figure 3 The intersection of the protection curve redrawn according to the braking force level in the figure) and the time when the train corresponding to the intersection is running in the long downhill section is recorded as t 1time.

[0081] In order to achieve the maximum braking force before the train speed reaches the safety limit speed when the train is running along the third coasting curve, the train should be 1 -t 加压 ) moment, and start planning the train's "cyclic braking-coasting" strategy. 1 -t 加压 The distance traveled by the train at time ) is denoted as s 1 At this time, the braking force applied by the train is the same as the braking force corresponding to the decompression protection curve.

[0082] In (t 1 -t 加压 ) The time for which the train applies the braking force is at least the minimum braking time t allowed by the braking operation 最小制动 . In (t 1 -t 加压 ) The braking time of the train reaches the minimum braking time t 最小制动 After that, through the minimum relief speed v 缓解 , judge the train after the minimum braking time (ie (t 1 -t 加压 +t 最小制动 ) is the speed greater than the minimum relief speed v 缓解 . And (t 1 -t 加压 +t 最小制动 ) is recorded as t 2 time.

[0083] When the train speed is less than or equal to the minimum relief speed v 缓解 , the train will continue to brake until it stops. When the speed of the train is greater than the minimum relief speed v 缓解 , the train determines whether to brake or coast based on the terminal coasting curve.

[0084] When t 2 The train speed and travel distance at the time satisfy the terminal coasting curve, that is, Figure 3 At this moment, the train's distance speed point (v, s) falls on the terminal coasting curve, and the train cancels the brakes and coasts until it leaves the braking zone. 2 If the speed and travel distance of the train at this moment do not meet the terminal coasting curve, then t 2 The train speed at the time is differentiated from the point (v, s) forward (i.e. the direction of train movement) and plotted along the s-axis (t 缓解 +t 惰行 +t 加压 ) time, ensuring that the train can 缓解 +t惰行 +t 加压 ) time that the train can complete the process of canceling the brake and re-braking the train. Among them, v 缓解 The time interval from the beginning of train braking relief to full relief, that is, the time required for the train to cancel the brake; t 惰行 It is the minimum operating state conversion time that needs to be maintained as specified in the train operating regulations, that is, the minimum idling time that the train maintains between two braking applications.

[0085] When the fourth coasting curve and the pressure protection curve intersect, then at t 2 After the time, the train continues to brake to prevent the train speed from exceeding the safety limit speed; when the fourth coasting curve and the pressure protection curve have no intersection, the train is at t 2 Immediately release the brakes and allow the train to coast until the train reaches (t 2 +t 缓解 +t 惰行 ) moment, the distance speed point of the train is (v 2 ,s 2 ) and apply the brakes again. At the same time, the minimum release speed v 缓解 , End point coasting curve judgment (t 2 +t 缓解 +t 惰行 ) The train brakes and maintains the minimum braking time t 最小制动 Check whether you need to stop, brake or coast.

[0086] The time when the train releases the brakes each time is recorded as t i (i>2), (t i +t 缓解 +t 惰行 The distance travelled by the train at the time ) is denoted as s i . Re-judge the train at (t i +t 缓解 +t 惰行 ) and maintain the minimum braking time t 最小制动 Is the train speed after the test greater than the minimum relief speed v 缓解 When the train is at (t i +t 缓解 +t 惰行 ) and maintain the minimum braking time t 最小制动 The train speed after is greater than the minimum relief speed v 缓解 , the train speed and travel distance at this moment will be re-judged to see whether they meet the terminal coasting curve; otherwise, the train will continue to brake until it stops. i +t 缓解 +t 惰行 ) The train passes the minimum braking time t 最小制动The speed and travel distance after braking satisfy the end-point coasting curve, that is, Figure 3 The distance and speed of the train at this moment (v i ,s i ) falls on the terminal coasting curve, the train cancels the brakes and coasts out of the braking zone. i +t 缓解 +t 惰行 ) The train passes the minimum braking time t 最小制动 If the speed and travel distance after braking do not meet the terminal coasting curve, it is necessary to recalibrate (t i +t 缓解 +t 惰行 ) The train passes the minimum braking time t 最小制动 The train speed and distance after braking are used to draw a coasting curve, and the relationship between the coasting curve pressure protection curve is re-evaluated until the train (t i +t 缓解 +t 惰行 ) and maintain the minimum braking time t 最小制动 The speed and travel distance of the mine car meet the terminal coasting curve.

[0087] When (t i +t 缓解 +t 惰行 ) and the train brakes at the minimum braking time t 最小制动 When the final speed is less than or equal to the speed corresponding to the terminal coasting curve, the train brakes are immediately cancelled to allow the train to coast out of the braking zone.

[0088] The electronic device provided by the present invention includes: a processor and a memory. The memory stores a computer program, and the computer program can realize the calculation of the equivalent slope, the drawing of the pressure reduction protection curve, the correction of the starting point of the braking section and the entrance speed of the starting point, the determination of the conditions for the train to cancel the brake and exit the braking section, and the formulation of the train's "cyclic braking-coasting" planning strategy. The processor is connected to the memory signal, and can generate instructions for controlling the running state of the train by calling the computer program stored in the memory, thereby controlling the braking or coasting of the train, and realizing the various steps of the long downhill cyclic braking method of the freight train. In addition, the present invention also provides a computer-readable storage medium, on which a computer program is stored, and the various steps of the long downhill cyclic braking method of the freight train can be realized by executing the computer program.

[0089] In summary, the present invention adopts a real-time planning algorithm based on differential calculation and utilizes the train coasting model to formulate a "cyclic braking-coiling" planning strategy for the train in a long downhill section, thereby realizing automatic driving of the train in a long downhill scenario and improving the accuracy and real-time performance of the "cyclic braking-coiling" planning strategy; at the same time, by drawing a decompression protection curve, the risk of train speeding is effectively avoided and the safety of train operation is ensured.

[0090] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A method for cyclic braking of a freight train on a long downhill slope, characterized in that: The specific steps include: Step S1, determining a long downhill section and determining a safe speed limit of the train; Step S2, determining the starting point of the braking section and the entrance speed of the starting point, and determining the conditions for the train to cancel the braking and exit the braking section; Step S3, determining the time when the train starts braking according to the starting point of the braking section and the entrance speed of the starting point, and the train brakes at the time when braking starts; Step S4, judging whether the speed of the train after braking meets the train running speed requirement; when the train speed meets the train running speed requirement, judging whether the train speed meets the condition of cancelling the braking and leaving the braking section; when the train speed does not meet the condition of cancelling the braking and leaving the braking section, the coasting model is built through the train speed point after braking, and judging whether the train needs to brake or cancel the brake according to the safety limit speed; Repeat step S4 until the speed of the train meets the condition for canceling the brakes and leaving the braking section.

2. The method for long downhill cyclic braking of a freight train according to claim 1, characterized in that: In step S2, the method for determining the starting point of the braking interval and the entrance speed of the starting point includes: The distance and speed point of the train when the train starts braking according to the brake spectrum is taken as the starting point of the original braking interval, and the train speed corresponding to the starting point of the original braking interval is the initial speed v0 of the original starting point; According to the equivalent gradient formation conditions of the line, the coasting time Δt0 required for the train to coast at the original starting point entrance speed v0 until the train speed reaches the safety limit speed is calculated, and the first coasting curve of the train in the coasting time Δt0 is drawn; wherein the safety limit speed is the maximum safe speed of the train set according to the long downhill section; By comparing the train braking time t 加压 and the coasting time Δt0, determine whether it is necessary to correct the starting point of the braking interval and the entry speed of the starting point; when the braking time is less than the coasting time, there is no need to correct the braking interval, the starting point of the braking interval is the original starting point of the braking interval, and the entry speed v1 of the starting point is the original entry speed v0 of the starting point.

3. The method for long downhill cyclic braking of a freight train according to claim 2, characterized in that: In step S2, the method for determining the starting point of the braking interval and the entrance speed of the starting point also includes: When the braking time t 加压 When the time is greater than or equal to the coasting time Δt0, the train needs to brake in advance, the braking section needs to be corrected, and the starting point of the braking section and the entrance speed of the starting point need to be corrected; Methods for correcting the starting point and the entrance speed of the braking interval include: The train braking time is at least (t 加压 -Δt0); according to the time of advance braking of the train, the first coasting curve is extended in the opposite direction of the train running, and a second coasting curve corresponding to the time of advance braking of the train is drawn; the left endpoint of the second coasting curve is taken as the starting point of the train braking section, and the train speed v0' corresponding to this point is the entry speed v1 of the starting point.

4. The long downhill cyclic braking method for freight trains according to claim 1, characterized in that: In step S2, the method for determining the condition for the train to cancel braking and exit the braking section includes: The final speed of the train when it exits the long downhill section is taken as the speed v2 at the end of the braking section, and the speed v2 at the end of the braking section is differentiated in the opposite direction of the train operation to draw a terminal coasting curve with the speed v2 at the end of the braking section as the end point; the condition for the train to cancel braking and exit the braking section is that the speed of the train is less than or equal to the speed corresponding to the terminal coasting curve.

5. The method for long downhill cyclic braking of a freight train according to claim 3, characterized in that: In step S3, the method for determining the time when the train starts braking includes: The differential calculation is performed from the entrance speed v1 at the starting point of the braking section along the train running direction, and the third coasting curve is drawn. The time when the train speed reaches the safety limit speed when the train travels along the third coasting curve is recorded as time t1; the time when the train starts braking is (t1-t 加压 ).

6. The method for long downhill cyclic braking of a freight train according to claim 5, characterized in that: In step S4, the method for determining whether the train speed meets the train running speed requirement includes: Set the minimum relief speed for trains on long downhill sections; When the train is at (t1-t 加压 ) and the braking has been maintained for the minimum braking time t 最小制动 After that, if the train speed is less than or equal to the minimum relief speed, the train will continue to brake until it stops; when the train is at (t1-t 加压 ) and the braking has been maintained for the minimum braking time t 最小制动 After that, if the speed of the train is greater than the minimum relief speed, the train determines whether to brake or coast based on the terminal coasting curve.

7. The method for long downhill cyclic braking of a freight train according to claim 6, characterized in that: In step S4, the method for determining whether the train speed satisfies the condition for canceling the brake and exiting the braking section includes: The train is at (t1-t 加压 ) and the braking has been maintained for the minimum braking time t 最小制动 After that, it is determined whether the train speed and the distance traveled at this time meet the conditions for canceling the brake and leaving the braking section, and the train is moved to the next stop (t1-t 加压 ) and maintain the minimum braking time t 最小制动 The moment after is recorded as moment t2; When the train speed at time t2 meets the conditions for canceling the brakes and exiting the braking section, the train immediately cancels the brakes and coasts out of the braking section.

8. The method for long downhill cyclic braking of a freight train according to claim 7, characterized in that: In step S4, the method for judging whether the train needs to brake or cancel the brake according to the safety limit speed includes: When the train speed at time t2 does not meet the conditions for canceling the brake and leaving the braking zone, the train speed and distance point at time t2 are modeled for coasting, and the train speed and distance point at time t2 are differentiated along the train running direction to obtain (t 缓解 +t 惰行 +t 加压 ) time; where t 缓解 The time required for the train to release the brakes; t 惰行 The minimum operating mode conversion time required to be maintained as specified in the train operating regulations; When the fourth coasting curve reaches the train's safety limit speed, the train keeps braking at time t2; when the fourth coasting curve does not reach the train's safety limit speed, the train immediately cancels the brakes at time t2, allowing the train to coast, and at (t2+t 缓解 +t 惰行 ) and re-evaluate the train's position at (t2+t 缓解 +t 惰行 ) moment and maintain the minimum braking time t 最小制动 Check whether the speed after braking meets the conditions for canceling the braking and exiting the braking zone.

9. The method for cyclic braking of a freight train on a long downhill slope according to claim 8, characterized in that: In step 4, the method of repeatedly determining whether the train speed meets the train running speed requirement includes: The time when the train releases the brakes each time is recorded as t i , and i>2; when the train is at (t i +t 缓解 +t 惰行 ) and maintain the minimum braking time t 最小制动 When the speed after the train is less than or equal to the minimum relief speed, the train will brake until the train stops. i +t 缓解 +t 惰行 ) and maintain the minimum braking time t 最小制动 When the subsequent speed is greater than the minimum relief speed, it is further determined whether the train speed meets the conditions for canceling the brakes and exiting the braking zone.

10. The method for long downhill cyclic braking of a freight train according to claim 9, characterized in that: In step 4, the method of repeatedly determining whether the train speed satisfies the condition for canceling the brake and traveling out of the braking section includes: When (t i +t 缓解 +t 惰行 ) The train passes the minimum braking time t 最小制动 When the speed after braking meets the conditions for canceling the brake and exiting the braking section, the train cancels the brake and coasts out of the braking section; when (t i +t 缓解 +t 惰行 ) The train passes the minimum braking time t 最小制动 When the speed after braking does not meet the conditions for canceling the brake and leaving the braking zone, the train is i +t 缓解 +t 惰行 ) and maintain the minimum braking time t 最小制动 The coasting model is built based on the train speed and distance points after the coasting, and a coasting curve is drawn. It is judged whether the speed of the train along the coasting curve exceeds the safety limit speed. When the train speed exceeds the safety limit speed, the train continues to brake. When the train speed does not exceed the safety limit speed, it is repeatedly judged whether the train speed meets the conditions for canceling the brakes and moving out of the braking interval, until the train speed meets the conditions for canceling the brakes and moving out of the braking interval, so that the train coasts out of the braking interval.

11. The method for long downhill cyclic braking of a freight train according to claim 1, characterized in that: In the step S1, the method for determining the long downhill section includes: a method for calculating the equivalent slope; Methods for calculating equivalent slope include: According to the actual line slope, the line is divided into multiple sections; multiple sampling points are evenly set in each section, and the arrival of the train head at the sampling point is used as the sampling standard to calculate the slope resistance encountered by the train at each sampling point; according to the number of sampling points in the section, the average slope resistance of the section is calculated; and according to the average slope resistance and the total mass of the train, the line section is converted into an equivalent slope section; wherein, the train slope resistance at each sampling point is the sum of the slope resistances calculated for each carriage according to the slope at which it is located when the train head arrives at the sampling point.

12. The method for long downhill cyclic braking of a freight train according to claim 1, characterized in that: In step S1, the method for calculating the safety limited speed includes: According to the brake spectrum, the braking decompression of the train at the maximum equivalent slope in the long downhill section is obtained, and the relationship between the speed and the travel distance of the train when the train is under maximum full-train braking corresponding to the braking decompression is calculated; according to the relationship between the speed and the travel distance of the train and the protection curve, a decompression protection curve is drawn; the speed point on the decompression protection curve is the safe limit speed of the train.

13. The method for long downhill cyclic braking of a freight train according to claim 12, characterized in that: The method for drawing a protection curve comprises: The train protection curve is drawn according to the calculated slope and length of the equivalent slope section and the relationship between the speed of the train and the travel distance under the maximum braking commonly used by the train under the equivalent slope; Among them, the speed point on the protection curve is the speed limit of the train.

14. The method for long downhill cyclic braking of a freight train according to claim 13, characterized in that: The safety limit speed of the train does not exceed the limit speed.

15. An electronic device, characterized in that: The method comprises a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the long downhill cyclic braking method for a freight train as described in claims 1-14 is implemented.

16. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed, the long downhill cyclic braking method for a freight train as described in claims 1-14 can be implemented.

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