A parking brake method and system for a maglev train

Abstract

This invention relates to a parking braking method and system for maglev trains. The method includes: when the maglev train's speed is at the electro-hydraulic conversion speed point, determining the stage operation sequence according to a corresponding relationship; passing the electro-hydraulic conversion speed point by successively decreasing the stage operation sequence; then acquiring the current state information of the maglev train from the ATO in real time; determining the target deceleration value based on the current state information; determining the stage ratio according to the corresponding relationship and the target deceleration value; applying the stage ratio to the maglev train in a periodic square wave form until the target deceleration value is reached; if the distance between the maglev train and the parking point is a first predetermined distance, then re-determining the target deceleration value; otherwise, when the distance between the maglev train and the parking point is a second predetermined distance, gradually increasing the stage to achieve a fixed-point stop. This invention enables precise stopping of maglev trains under hydraulic braking, ensuring parking comfort and improving the passenger experience.

Description

Technical Field

[0001] This invention relates to the field of maglev train parking technology, and in particular to a maglev train parking braking method and system. Background Technology

[0002] Due to the inherent characteristics of maglev trains, their braking system consists of both electric and mechanical braking. At low speeds, mechanical braking is required, with hydraulic braking being the most widely used method. Therefore, braking a maglev train involves switching between electric and hydraulic braking. Electric and hydraulic braking differ in their mechanisms; the time delay from initial application to braking response differs, and the deceleration produced at the same speed level is also inconsistent.

[0003] The varying delay times pose significant challenges to ATO (Automatic Train Control) vehicle control, making the braking force output a variable-delay system during electro-hydraulic conversion. As the proportion of hydraulic braking increases, the braking delay time also lengthens, necessitating more flexible parking braking strategies. Furthermore, the deceleration corresponding to the same braking level differs between electric and hydraulic braking. Due to the inherent characteristics of hydraulic braking, the deceleration difference between adjacent braking levels can be greater than with electric braking, making it impossible to achieve a target deceleration value by applying a fixed braking level. Additionally, hydraulic braking exhibits a slow start; the delay time from initial hydraulic braking to actual application is significantly longer than the reaction time for level switching once hydraulic braking connection is established.

[0004] Therefore, a key issue is how to achieve smooth and precise stopping of maglev trains by optimizing the level application strategy while fully considering the conversion between electric braking and hydraulic braking; and a standardized stopping scheme needs to be developed for the characteristics of maglev trains to achieve a satisfactory stopping result.

[0005] In addition, since most maglev trains currently use a graded braking system, they often cannot directly provide the ideal braking deceleration when following the ideal braking curve set offline, which results in the inability to achieve the ideal speed tracking effect and thus fails to meet the requirements of comfort and precise stopping. Summary of the Invention

[0006] The purpose of this invention is to provide a parking braking method and system for maglev trains, which can achieve precise stopping of maglev trains under hydraulic braking, while ensuring parking comfort and improving the passenger experience.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] A method for stopping and braking a maglev train includes:

[0009] Based on the test data and vehicle parameter characteristics of the maglev train, the corresponding relationship between the braking level and acceleration during electric braking and hydraulic braking, as well as the electro-hydraulic conversion speed point, are determined; the electro-hydraulic conversion speed point is when the speed of the maglev train equals a set speed threshold.

[0010] When the speed of the maglev train is the electro-hydraulic conversion speed point, the stage operation sequence is determined according to the correspondence between stage position and acceleration; and the electro-hydraulic conversion speed point is passed by successively decreasing the stage operation sequence.

[0011] After electro-hydraulic conversion, the maglev train enters the hydraulic braking stage, and obtains the current status information of the maglev train in real time from the ATO; and determines the target deceleration value based on the current status information; the current status information includes: current train speed, current position, and distance from the stopping point;

[0012] The stage ratio is determined based on the correspondence between stage and acceleration, as well as the target deceleration value.

[0013] The stage ratio is applied to the maglev train in the form of a periodic square wave until the target deceleration value is reached;

[0014] Determine whether the distance between the maglev train and the stopping point is the first preset distance;

[0015] If the first set distance is selected, return to the step of determining the target deceleration value based on the current state information;

[0016] If the distance is not the first set distance, then when the distance between the maglev train and the parking point is the second set distance, the distance will be gradually increased to achieve fixed-point parking.

[0017] Optionally, determining the target deceleration value based on the current state information specifically includes:

[0018] Using formula Determine the target deceleration value;

[0019] in, For the target deceleration value, This is the current train speed value. This is the distance from the parking spot.

[0020] Optionally, determining the stage ratio based on the correspondence between stage and acceleration and the target deceleration value specifically includes the following formula:

[0021] ;

[0022] Where x1 and x2 are the acceleration values ​​corresponding to different levels, and b1 and b2 are the proportions of x1 and x2 allocated to each other. This represents the number of sampling points within 1 second.

[0023] Optionally, the test data includes: real-time data on level, speed, acceleration, and travel distance during the maglev train test.

[0024] A parking brake system for a maglev train includes:

[0025] The module for determining the correspondence and electro-hydraulic conversion speed point is used to determine the correspondence between the level and acceleration during electric braking and hydraulic braking, as well as the electro-hydraulic conversion speed point, based on the test data and vehicle parameter characteristics of the maglev train; the electro-hydraulic conversion speed point is when the speed of the maglev train equals a set speed threshold.

[0026] The electro-hydraulic conversion speed point control module is used to determine the stage operation sequence based on the correspondence between stage position and acceleration when the speed of the maglev train is at the electro-hydraulic conversion speed point; and to pass the electro-hydraulic conversion speed point by successively decreasing the stage operation sequence.

[0027] The target deceleration value determination module is used to obtain the current status information of the maglev train in real time from the ATO after the electro-hydraulic conversion and when the maglev train enters the hydraulic braking stage; and to determine the target deceleration value based on the current status information; the current status information includes: current train speed, current position, and distance from the stopping point;

[0028] The stage ratio determination module is used to determine the stage ratio based on the correspondence between stage and acceleration and the target deceleration value;

[0029] The periodic square wave control module is used to apply the stage ratio to the maglev train in the form of a periodic square wave until the target deceleration value is reached.

[0030] The judgment module is used to determine whether the distance between the maglev train and the parking point is the first preset distance;

[0031] The loop module is used to return the target deceleration value determination module if the first set distance is reached;

[0032] The parking module is used to achieve fixed-point parking by gradually increasing the distance between the maglev train and the parking point if the distance is not the first preset distance, but the second preset distance.

[0033] Optionally, the target deceleration value determination module specifically includes:

[0034] Using formula Determine the target deceleration value;

[0035] in, For the target deceleration value, This is the current train speed value. This is the distance from the parking spot.

[0036] A maglev train parking braking system includes: at least one processor, at least one memory, and computer program instructions stored in the memory, which implement the maglev train parking braking method when the computer program instructions are executed by the processor.

[0037] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0038] (1) The maglev train parking braking method and system provided by the present invention fully considers the characteristics of electric braking and hydraulic braking during the switching process. The correspondence between the electric braking and hydraulic braking levels and deceleration is obtained by comparing actual data. When applying the level, it is fully considered. Without adding any other equipment, the strategy optimization effectively avoids drastic fluctuations in deceleration value and improves passenger comfort.

[0039] (2) The maglev train parking braking method and system provided by the present invention achieves the output of target deceleration by switching between two levels during the hydraulic braking process, avoiding the problems of unresponsive level caused by frequent level switching and poor comfort caused by constant level electro-hydraulic.

[0040] (3) The maglev train parking braking method and system provided by the present invention mainly gives the operation strategy of applying the level position based on the actual data characteristics. No other hardware equipment needs to be added. The train runs smoothly and parking comfort is improved by improving the level position application strategy. All the parameters involved can be obtained by precise calculation, which has great guiding significance for engineering implementation and engineering improvement. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of a parking and braking method for a maglev train provided by the present invention;

[0043] Figure 2 A schematic diagram of a parking braking method for a maglev train provided by the present invention;

[0044] Figure 3 A diagram showing the deceleration variation of the electro-hydraulic section during actual operation of a maglev train parking braking method provided by the present invention;

[0045] Figure 4 The ideal speed diagram calculated during train operation for a maglev train parking braking method provided by the present invention;

[0046] Figure 5 The present invention provides a method for stopping and braking a maglev train, which obtains a speed-distance curve by applying a periodic square wave stage during train operation. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] To address the issues of poor braking comfort and insufficient consideration of the braking characteristics of maglev trains in existing parking braking strategies, this invention provides a parking braking method and system for maglev trains. This system enables precise stopping of maglev trains under hydraulic braking while ensuring parking comfort and improving the passenger experience.

[0049] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0050] The mechanical braking commonly used in maglev trains mainly includes air-to-liquid braking and hydraulic braking. Air-to-liquid braking, as the name suggests, uses air-to-liquid conversion to achieve pressurization and thus braking. Air-to-liquid braking systems are complex in structure, heavy in mass, and occupy a lot of space under the train. Currently, the more commonly used system is the hydraulic braking system, which is more compact than air-to-liquid braking.

[0051] Vehicles typically have traction levels (acceleration, usually 10 levels) and braking levels (deceleration, usually 10 levels excluding coasting). Each level corresponds to a different proportion of traction and braking force; the larger the level value, the greater the traction and braking force. This invention only relates to braking levels.

[0052] Whether it's traction or braking, it takes time for the force to be applied and then reflected in the train's acceleration and speed. During the braking phase of a maglev train, due to the existence of different braking methods (electric braking, hydraulic braking) and the switching between different braking methods, the delay time is not a constant value.

[0053] Figure 1 This is a schematic diagram of a parking and braking method for a maglev train provided by the present invention. Figure 2The schematic diagram of a parking and braking method for a maglev train provided by the present invention is as follows: Figure 1 and Figure 2 As shown, the present invention provides a method for stopping and braking a maglev train, comprising:

[0054] S101, based on the test data and vehicle parameter characteristics of the maglev train, determine the correspondence between the braking level and acceleration during electric braking and hydraulic braking, as well as the electro-hydraulic conversion speed point; the electro-hydraulic conversion speed point is when the speed of the maglev train equals a set speed threshold; the speed of the maglev train decreases to the set speed threshold. The process of switching from electric braking to hydraulic braking begins at this time. The test data includes real-time data on level, speed, acceleration, and travel distance during the maglev train test.

[0055] The correspondence between braking levels and acceleration is based on the analysis of train operation data according to a time series at the electro-hydraulic conversion speed point. Speeds above this level indicate the electric braking phase, while speeds below this level indicate the electro-hydraulic hybrid / hydraulic braking phase. During electric braking and electro-hydraulic hybrid / hydraulic braking phases, the correspondence between each braking level and acceleration is determined sequentially by reading the time difference between the application of the braking level and the onset of acceleration response. For example, if the braking level was previously 0 and the speed was... Immediately begin applying a -2 level bit operation to read from the data. After acceleration jumps from 0 to This allows us to determine the current speed. Below, the acceleration corresponding to level 0 is in The delay time for left and right positions and levels from 0 to -2 is in about.

[0056] S102, when the speed of the maglev train is the electro-hydraulic conversion speed point, the stage operation sequence is determined according to the correspondence between stage position and acceleration; and the stage operation sequence is successively reduced to pass the electro-hydraulic conversion speed point, so that the train passes through the electro-hydraulic conversion speed point smoothly, and the deceleration change is maintained within a certain fluctuation range, thereby improving passenger comfort.

[0057] S103, After the electro-hydraulic conversion, the maglev train enters the hydraulic braking stage, and obtains the current status information of the maglev train in real time from the ATO; and determines the target deceleration value based on the current status information; the current status information includes: current train speed, current position, and distance from the stopping point;

[0058] S103 specifically includes:

[0059] Using formula Determine the target deceleration value;

[0060] in, For the target deceleration value, This is the current train speed value. This is the distance from the parking spot.

[0061] Because the stopping distance within the station is short, the deceleration differences between the smaller hydraulic braking levels are significant. The required deceleration value within the station is generally... Furthermore, applying a constant hydraulic braking level cannot achieve the desired deceleration. Therefore, it is considered to switch between the two levels by applying a periodic square wave, so as to achieve an average deceleration equal to the target deceleration while fully considering the hydraulic braking delay, which can further enable the maglev train to stop smoothly and accurately.

[0062] S104, determine the stage ratio based on the correspondence between stage and acceleration and the target deceleration value;

[0063] S104 specifically includes the following formulas:

[0064] ;

[0065] Where x1 and x2 are the acceleration values ​​corresponding to different levels, and b1 and b2 are the proportions of x1 and x2 allocated to each other. This represents the number of sampling points within 1 second.

[0066] Based on the correspondence between level and acceleration, we can... Each sampling point is proportionally assigned the corresponding acceleration values ​​x1 and x2 for different levels, and the number of times b1 and b2 are continuously applied.

[0067] S105 applies the stage ratio to the maglev train in the form of a periodic square wave until the target deceleration value is reached.

[0068] The form of a periodic square wave refers to the periodicity of the output of the stages. For example, in order to make the average deceleration reach the desired deceleration value, it is calculated that 2 -2 stages and 5 -3 stages need to be applied. In this case, 2 -2 stages and 5 -3 stages can be regarded as a period, and the stages are applied in this sequence until the train reaches the calibration point.

[0069] S106, determine whether the distance between the maglev train and the parking point is the first set distance; if it is the first set distance, return to the step of determining the target deceleration value based on the current status information; that is, perform secondary calculation and apply the ratio level.

[0070] As a specific example, at the distance from the parking point The deceleration value required for stopping is recalculated. The level ratio is recalculated before application. To calibrate the vehicle control error, at a distance of 10m or 5m from the parking point, the required target deceleration value is recalculated based on the current speed and distance from the parking point. The level ratio is then recalculated, and the level is applied using a periodic square wave so that the average deceleration over the last 10m or 5m distance tends to the target deceleration.

[0071] , ;

[0072] S107, if not the first set distance, then when the distance between the maglev train and the parking point is the second set distance, the level is gradually increased to achieve fixed-point parking.

[0073] As a specific example, the output level is gradually increased from a distance of Cm from the parking point to a constant level, so that the vehicle can be stopped smoothly and accurately.

[0074] When the train speed is V and the distance from the stopping point is S, applying certain level sequences step by step after the square wave level can enable the train to stop at a fixed point. The calculation of the level sequence still uses... This is achieved through a table showing the relationship between acceleration and position. A train stopping at a fixed point means that after braking, the train's speed is zero, and the positional deviation is within a reasonable range (generally, a deviation of [value missing] is required). This meets the industry's parking requirements.

[0075] The functions and technical effects achieved by the present invention are explained in detail below through specific implementations:

[0076] The relationship between braking level and acceleration involved in this embodiment is as follows:

[0077] Level 0 corresponds to the deceleration range ;

[0078] deceleration range corresponding to level -2 ;

[0079] deceleration range corresponding to level -3 ;

[0080] deceleration range corresponding to level -4 ;

[0081] deceleration range corresponding to level -5 ;

[0082] deceleration range corresponding to level -6 ;

[0083] deceleration range corresponding to level -9 .

[0084] This embodiment uses a square wave strategy to apply phase-wise braking to a maglev train, reducing the train speed to 13. At this point, the train begins to switch from electric braking to hydraulic braking, and the distance between the train and the stopping point is 23 meters. For example... Figure 3 As shown, when a constant pressure of -9 is applied during the electro-hydraulic conversion speed point, a sudden change in deceleration occurs. According to model analysis, this sudden change is due to the excessively rapid decrease in the electric braking current during the electro-hydraulic conversion. Due to the delay in hydraulic braking, the corresponding hydraulic braking force is not replenished in time, resulting in the deceleration value first decreasing and then increasing.

[0085] To reduce abrupt changes in deceleration during the electro-hydraulic process, a level of -9 is applied at the beginning of the electro-hydraulic transition, followed by a gradual decrease from level -9 to levels -6 and -4, thus transitioning from electric braking to hydraulic braking in a gradual manner.

[0086] After the hydraulic brakes were applied, the train speed was 8.8 km / h. It's about 15 meters from the parking spot. According to... Calculation yields Then from the formula Therefore, we can obtain The train is braked by periodically applying two -2 level positions and five -3 level positions of square wave positions (since the deceleration value corresponding to the level obtained from the data is a range, the average value of the numbers in this range is taken to represent the deceleration value corresponding to the level for ease of calculation).

[0087] The speed was 4 at a distance of 5m from the parking spot. According to the calculation, it can be obtained The train is braked by periodically applying a square wave sequence of 6 -2 level bits and 2 -3 level bits.

[0088] Finally, at a distance of 3 meters from the parking point (based on actual test drive data), the speed value was 2. The output level is gradually increased from left to right, from -4, -6 to -12, to stop the train. The resulting ideal speed-distance curve and the speed-distance curve obtained according to the operation strategy are shown below. Figure 4 , Figure 5 As shown.

[0089] In view of the above method, the present invention also provides a maglev train parking braking system, comprising:

[0090] The module for determining the correspondence and electro-hydraulic conversion speed point is used to determine the correspondence between the level and acceleration during electric braking and hydraulic braking, as well as the electro-hydraulic conversion speed point, based on the test data and vehicle parameter characteristics of the maglev train; the electro-hydraulic conversion speed point is when the speed of the maglev train equals a set speed threshold.

[0091] The electro-hydraulic conversion speed point control module is used to determine the stage operation sequence based on the correspondence between stage position and acceleration when the speed of the maglev train is at the electro-hydraulic conversion speed point; and to pass the electro-hydraulic conversion speed point by successively decreasing the stage operation sequence.

[0092] The target deceleration value determination module is used to obtain the current status information of the maglev train in real time from the ATO after the electro-hydraulic conversion and when the maglev train enters the hydraulic braking stage; and to determine the target deceleration value based on the current status information; the current status information includes: current train speed, current position, and distance from the stopping point;

[0093] The stage ratio determination module is used to determine the stage ratio based on the correspondence between stage and acceleration and the target deceleration value;

[0094] The periodic square wave control module is used to apply the stage ratio to the maglev train in the form of a periodic square wave until the target deceleration value is reached.

[0095] The judgment module is used to determine whether the distance between the maglev train and the parking point is the first preset distance;

[0096] The loop module is used to return the target deceleration value determination module if the first set distance is reached;

[0097] The parking module is used to achieve fixed-point parking by gradually increasing the distance between the maglev train and the parking point if the distance is not the first preset distance, but the second preset distance.

[0098] The target deceleration value determination module specifically includes:

[0099] Using formula Determine the target deceleration value;

[0100] in, For the target deceleration value, This is the current train speed value. This is the distance from the parking spot.

[0101] In order to execute the methods corresponding to the above embodiments and achieve the corresponding functions and technical effects, the present invention provides a maglev train parking braking system, comprising: at least one processor, at least one memory, and computer program instructions stored in the memory, wherein the maglev train parking braking method is implemented when the computer program instructions are executed by the processor.

[0102] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0103] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for stopping and braking a maglev train, characterized in that, include: Based on the test data and vehicle parameter characteristics of the maglev train, the corresponding relationship between the braking level and acceleration during the electric braking and hydraulic braking processes, as well as the electro-hydraulic conversion speed point, are determined. The electro-hydraulic conversion speed point is when the speed of the maglev train equals a set speed threshold; the test data includes: real-time data on the stage, speed, acceleration, and travel distance during the maglev train test; each stage corresponds to a different proportion of traction and braking force; When the speed of the maglev train is the electro-hydraulic conversion speed point, the stage operation sequence is determined according to the correspondence between stage position and acceleration; and the electro-hydraulic conversion speed point is passed by successively decreasing the stage operation sequence. After electro-hydraulic conversion, the maglev train enters the hydraulic braking stage, and obtains the current status information of the maglev train in real time from the ATO; and determines the target deceleration value based on the current status information; the current status information includes: current train speed, current position, and distance from the stopping point; The stage ratio is determined based on the correspondence between stage and acceleration, as well as the target deceleration value. The stage ratio is applied to the maglev train in the form of a periodic square wave until the target deceleration value is reached; Determine whether the distance between the maglev train and the stopping point is the first preset distance; If the first set distance is selected, return to the step of determining the target deceleration value based on the current state information; If the distance is not the first set distance, then when the distance between the maglev train and the parking point is the second set distance, the distance will be gradually increased to achieve fixed-point parking.

2. The method for stopping and braking a maglev train according to claim 1, characterized in that, Determining the target deceleration value based on the current state information specifically includes: Using formula Determine the target deceleration value; in, For the target deceleration value, This is the current train speed value. This is the distance from the parking spot.

3. The method for stopping and braking a maglev train according to claim 1, characterized in that, The determination of the stage ratio based on the correspondence between stage and acceleration, and the target deceleration value, is specifically... Including the following formulas: ； in, x 1. x 2 represents the acceleration values ​​corresponding to different pressure levels. b 1. b 2 are allocated according to proportions x 1. x The number of items in a 2:1 ratio 1 s Number of sampling points within, The target deceleration value.

4. A parking brake system for a maglev train, characterized in that, include: The module for determining the correspondence and electro-hydraulic conversion speed point is used to determine the correspondence between the level and acceleration during electric braking and hydraulic braking, as well as the electro-hydraulic conversion speed point, based on the test data and vehicle parameter characteristics of the maglev train. The electro-hydraulic conversion speed point is when the speed of the maglev train equals a set speed threshold; the test data includes: real-time data on the stage, speed, acceleration, and travel distance during the maglev train test; each stage corresponds to a different proportion of traction and braking force; The electro-hydraulic conversion speed point control module is used to determine the stage operation sequence based on the correspondence between stage position and acceleration when the speed of the maglev train is at the electro-hydraulic conversion speed point; and to pass the electro-hydraulic conversion speed point by successively decreasing the stage operation sequence. The target deceleration value determination module is used to obtain the current status information of the maglev train in real time from the ATO after the electro-hydraulic conversion and when the maglev train enters the hydraulic braking stage; and to determine the target deceleration value based on the current status information; the current status information includes: current train speed, current position, and distance from the stopping point; The stage ratio determination module is used to determine the stage ratio based on the correspondence between stage and acceleration and the target deceleration value; The periodic square wave control module is used to apply the stage ratio to the maglev train in the form of a periodic square wave until the target deceleration value is reached. The judgment module is used to determine whether the distance between the maglev train and the parking point is the first preset distance; The loop module is used to return the target deceleration value determination module if the first set distance is reached; The parking module is used to achieve fixed-point parking by gradually increasing the distance between the maglev train and the parking point if the distance is not the first preset distance, but the second preset distance.

5. A maglev train parking braking system according to claim 4, characterized in that, The target deceleration value determination module specifically includes: Using formula Determine the target deceleration value; in, For the target deceleration value, This is the current train speed value. This is the distance from the parking spot.

6. A parking brake system for a maglev train, characterized in that, include: The system comprises at least one processor, at least one memory, and computer program instructions stored in the memory, which, when executed by the processor, implement a maglev train parking braking method as described in any one of claims 1-3.

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