Surface emissivity measuring method, system and train

Abstract

The invention provides a surface emissivity measuring method and system and a train. Relates to the technical field of emissivity measurement and the technical field of rail trains. Under the condition that the temperature of the brake component meets the preset temperature distribution characteristic, the following operations are executed: determining a temperature measurement area on the surface of the brake component; performing temperature measurement on the temperature measurement area by using an infrared temperature measurement instrument, and calibrating the emissivity of the infrared temperature measurement instrument in the temperature measurement process; and determining the calibrated emissivity as the surface emissivity of the braking component.

Description

Technical Field

[0001] The present disclosure relates to the technical fields of emissivity measurement and rail trains, and particularly, to a method, a system, and a train for measuring surface emissivity. Background Art

[0002] Infrared thermometers have the advantages of fast response speed, non-contact, non-interference with the temperature field, and suitability for measurement in harsh environments. When using an infrared thermometer to measure the surface temperature of an object, the emissivity of the measured surface needs to be set in advance. The emissivity of an object's surface is related to factors such as the material, texture, roughness, color, temperature of the object's surface, and the relative position between the thermometer and the surface.

[0003] In the process of implementing the concept of the present disclosure, the inventors found that there are at least the following problems in the related art: If the wheel or brake disc part of a vehicle is cut off and then the surface emissivity of the object is measured, the material, texture, roughness, temperature field, and working state of the surface of the cut sample may change, making it difficult to ensure the accuracy of emissivity measurement. Summary of the Invention

[0004] In view of this, the present disclosure provides a method, a system, and a train for measuring surface emissivity.

[0005] One aspect of the present disclosure provides a method for measuring surface emissivity, including: performing multiple pure air brakings during the running of the train to raise the overall temperature of the braking member of the train; when the temperature of the braking member satisfies a predetermined temperature distribution characteristic, perform the following operations: determine the temperature measurement area on the surface of the braking member; use an infrared thermometer to measure the temperature of the temperature measurement area, and during the temperature measurement process, calibrate the emissivity of the infrared thermometer; determine the emissivity obtained by calibration as the surface emissivity of the braking member.

[0006] According to an embodiment of the present disclosure, the predetermined temperature distribution characteristic is that the difference between the surface temperature and the central temperature of the braking member is less than a predetermined threshold, and the surface temperature and the central temperature are within a predetermined temperature range.

[0007] According to an embodiment of the present disclosure, performing multiple pure air brakings includes: performing multiple consecutive pure air brakings, and the time interval between two adjacent pure air brakings is greater than a preset time threshold.

[0008] According to an embodiment of the present disclosure, the braking member includes a wheel and / or a brake disc.

[0009] According to an embodiment of the present disclosure, the surface emissivity measurement method further includes: arranging a surface temperature measuring instrument on the surface of the brake shoe and / or brake pad, wherein the brake shoe rubs against the wheel pair during pure air braking, and the brake pad rubs against the brake disc during pure air braking; during multiple pure air brakings, collecting multiple sets of first monitored temperatures by using the surface temperature measuring instrument; and determining whether the temperature of the braking member satisfies a predetermined temperature distribution characteristic according to the multiple sets of first monitored temperatures.

[0010] According to an embodiment of the present disclosure, the surface emissivity measurement method further includes: establishing a braking simulation model for the wheel and / or brake disc; based on the braking simulation model, simulating the pure air braking process of the wheel and / or brake disc under N braking strategies, and outputting N sets of simulated temperature change data corresponding to the wheel and / or brake disc under the N braking strategies; and determining a target braking strategy from the N braking strategies based on the N sets of simulated temperature change data.

[0011] According to an embodiment of the present disclosure, the surface emissivity measurement method further includes: assigning a reference emissivity to the infrared thermometer based on historical measurement data of the braking member; during multiple pure air brakings, measuring the temperature of the wheel and / or brake disc by using the infrared thermometer based on the reference emissivity, and obtaining multiple sets of second monitored temperatures; and determining whether the temperature of the braking member satisfies a predetermined temperature distribution characteristic according to the multiple sets of second monitored temperatures.

[0012] According to an embodiment of the present disclosure, calibrating the emissivity of the infrared thermometer includes: measuring the true temperature of the temperature measurement area; measuring the first temperature of the temperature measurement area based on a first emissivity set for the infrared thermometer; in the case where the first temperature and the true temperature do not satisfy a predetermined numerical condition, adjusting the first emissivity to a second emissivity, and completing the calibration of the emissivity of the infrared thermometer in the case where the second temperature of the temperature measurement area measured based on the second emissivity and the true temperature satisfy the predetermined numerical condition, wherein the second emissivity is the calibrated emissivity.

[0013] According to an embodiment of the present disclosure, determining the temperature measurement area on the surface of the braking member includes: determining the temperature measurement area on the surface of the braking member based on the installation position of the infrared thermometer installed near the braking member.

[0014] According to an embodiment of the present disclosure, determining the temperature measurement area on the surface of the braking member based on the installation position of the infrared thermometer installed near the braking member includes: determining a center point based on the intersection point of the extension line of the detection head of the infrared thermometer along the detection direction on the surface of the braking member; determining a measurement radius according to the linear distance between the detection head and the center point; and determining the temperature measurement area based on the center point and the measurement radius.

[0015] Another aspect of the present disclosure provides a surface emissivity measurement system, including: a braking device for performing multiple pure air brakings during the train's travel to raise the overall temperature of the braking member of the train; a measurement device for performing the following operations when the temperature of the braking member satisfies a predetermined temperature distribution characteristic: a first determination sub-module for determining a temperature measurement area on the surface of the braking member; a measurement sub-module for measuring the temperature of the temperature measurement area using an infrared thermometer and calibrating the emissivity of the infrared thermometer during the temperature measurement process; a second determination sub-module for determining the emissivity obtained by calibration as the surface emissivity of the braking member.

[0016] Another aspect of the present disclosure provides a train, including: a car body, a braking device, and a measurement device.

[0017] According to the embodiments of the present disclosure, by measuring the braking member during the train's travel, destructive behaviors such as cutting objects are avoided. This not only maintains the integrity and original working state of the braking member but also directly obtains its temperature and emissivity information during actual operation, ensuring that the measurement results accurately and real-time reflect the true characteristics of the braking member. Compared with the measurement method of cutting the braking member in the related art, the convenience and efficiency of measurement are improved, and the normal operation rhythm of the train is not affected. Among them, multiple brakings can ensure that the overall temperature of the braking component gradually increases. Compared with single braking or local heating that may cause local overheating or uneven temperature distribution, multiple pure air brakings can allow heat to fully conduct inside the braking member, enabling the braking member to reach a more stable and uniform temperature distribution state, which is conducive to accurately determining the temperature measurement area, avoiding temperature measurement errors caused by uneven temperature, and improving the accuracy of emissivity calibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Through the following description of the embodiments of the present disclosure with reference to the drawings, the above and other objects, features, and advantages of the present disclosure will become clearer. In the drawings:

[0019] Figure 1 Schematically shows a schematic diagram of the surface emissivity measurement method according to an embodiment of the present disclosure;

[0020] Figure 2 Schematically shows a flowchart of the surface emissivity measurement method according to an embodiment of the present disclosure;

[0021] Figure 3 Schematically shows a flowchart of monitoring the temperature of the braking member under multiple pure air brakings according to an embodiment of the present disclosure;

[0022] Figure 4A Schematically shows a schematic diagram of installing a surface thermometer on the brake shoe surface according to an embodiment of the present disclosure;

[0023] Figure 4B Schematically shown respectively is a schematic diagram of a surface temperature measuring instrument installed on the surface of a brake pad according to an embodiment of the present disclosure;

[0024] Figure 5A and Figure 5B Schematically shown is a schematic diagram of the relative installation position of a surface temperature measuring instrument and a braking member according to an embodiment of the present disclosure;

[0025] Figure 6A Schematically shown is a graph of the overall temperature change of a brake shoe after multiple pure air brakings according to an embodiment of the present disclosure;

[0026] Figure 6B Schematically shown is a graph of the local temperature change of a brake shoe after multiple pure air brakings according to an embodiment of the present disclosure;

[0027] Figure 7 Schematically shown is a flowchart of monitoring the temperature of a braking member during multiple pure air brakings according to another embodiment of the present disclosure;

[0028] Figure 8A Schematically shown is a schematic diagram of a simulation model of the temperature fields of a wheel and an axle during a tread braking process according to an embodiment of the present disclosure.

[0029] Figure 8B Schematically shown is a schematic diagram of a simulation model of the temperature fields of a brake disc, a wheel, and an axle during a wheel disc braking process according to an embodiment of the present disclosure;

[0030] Figure 9 Schematically shown is a flowchart of a method for determining a target braking strategy based on a simulation model according to an embodiment of the present disclosure;

[0031] Figure 10A Schematically shown is a graph of the overall temperature change of a wheel tread after multiple pure air brakings according to an embodiment of the present disclosure;

[0032] Figure 10B Schematically shown is a graph of the local temperature change of a wheel tread after multiple pure air brakings according to an embodiment of the present disclosure. Detailed implementation manners

[0033] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the following detailed description, for the sake of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, obviously, one or more embodiments can also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily obscuring the concepts of the present disclosure.

[0034] The terms used herein are merely for describing specific embodiments and are not intended to limit the present disclosure. The terms "including", "comprising", etc. as used herein indicate the presence of the described features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0035] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted to have a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0036] In cases where expressions similar to "at least one of A, B, and C, etc." are used, generally, it should be interpreted according to the meaning commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include, but is not limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0037] In the embodiments of the present disclosure, in aspects such as the collection, update, analysis, processing, use, transmission, provision, disclosure, storage, etc. of the involved data (for example, including but not limited to user personal information), they all comply with the provisions of relevant laws and regulations, are used for legal purposes, and do not violate public order and good customs. In particular, necessary measures are taken for user personal information to prevent illegal access to user personal information data and to safeguard user personal information security, network security, and national security.

[0038] In the embodiments of the present disclosure, before obtaining or collecting user personal information, the authorization or consent of the user has been obtained.

[0039] Any object as long as its temperature is higher than absolute zero will continuously radiate infrared rays into the surrounding space. The higher the temperature of the object, the greater the infrared ray energy radiated. An infrared thermometer receives the infrared rays emitted by an object, converts them into electrical signals, and then through a series of processing and calculations, finally displays the temperature of the object.

[0040] The ability of an object to emit infrared rays is represented by the emissivity, which is a value between 0 and 1. An infrared thermometer calculates the temperature based on the infrared energy emitted by an object, and the emissivity determines the proportional relationship between the actual infrared energy emitted by the object and the energy emitted by a theoretical blackbody (an ideal object with an emissivity of 1). The emissivity of an object's surface is related to factors such as the material, texture, roughness, color, temperature of the object's surface, and the relative position between the thermometer and the surface. Objects with different materials and surface states have different emissivities. If the emissivity is set inaccurately, it will lead to a deviation in the measured temperature.

[0041] However, during the heat capacity type test of a vehicle, the overall assessment of the heat capacity type test requires simulating the temperature field distribution of the wheels and brake discs during the actual operation of the train. If a part of the wheel or brake disc is cut to measure the emissivity, the microscopic structure of the specimen surface material will change, affecting the thermal radiation characteristics and emissivity, and destroying the original texture to change the law of thermal radiation emission and reflection. At the same time, cutting introduces additional heat to change the temperature field, which deviates from the actual temperature field of the components during the operation of the rail vehicle. Since the emissivity is related to temperature, the change in the temperature field will inevitably lead to inaccurate determination of the emissivity. If the local heating method using heating sheets is used for simulation testing, only the local temperature of the component surface can be increased, and it is difficult to simulate the complex temperature field changes of the entire wheel and brake disc under different operating conditions of the train.

[0042] According to the embodiments of the present disclosure, when a new train line is launched or a new vehicle model is put into use, the road conditions, gradients, curves, etc. of the new line are different from those of the existing line, and the performance of the new vehicle model and the coordinated operation between components also need to be verified. By allowing the train to run and brake multiple times on the new line, the wheels and brake discs experience temperature changes under various actual operating conditions, which can comprehensively evaluate the thermal performance of the train in the new environment or new design, providing accurate basic data for subsequent operation and maintenance. For example, when a new mountain line is opened, the train needs to brake and start frequently, and in this way, the heat generation, wear, etc. of the wheels and brake discs when dealing with large gradients and frequent braking can be understood.

[0043] In view of this, the embodiments of the present disclosure provide a surface emissivity measurement method, including: performing multiple pure air brakes during the train's travel to increase the overall temperature of the train's braking components; when the temperature of the braking components satisfies a predetermined temperature distribution characteristic, perform the following operations: determine the temperature measurement area on the surface of the braking components; use an infrared thermometer to measure the temperature of the temperature measurement area, and during the temperature measurement process, calibrate the emissivity of the infrared thermometer; determine the emissivity obtained by calibration as the surface emissivity of the braking components.

[0044] Figure 1 Schematically shows the schematic diagram of the surface emissivity measurement method of the embodiments of the present disclosure. Figure 2The following schematically shows a flow chart of a surface emissivity measurement method according to an embodiment of the present disclosure. Figure 1 , Figure 2 , the surface emissivity measurement method of the embodiment of the present disclosure is described.

[0045] like Figure 1 As shown, the infrared thermometer 101 is installed near the wheel 102 so that the detection head of the infrared thermometer 101 can face the wheel 102. When the vehicle brakes, the wheel 102 rubs and the temperature rises, and the infrared thermometer 101 measures the temperature of the wheel 102.

[0046] like Figure 2 As shown, the surface emissivity measurement method includes operations S210 to S220.

[0047] In operation S210 , pure air braking is performed multiple times during the traveling of the train to increase the overall temperature of the brake components of the train.

[0048] According to the embodiments of the present disclosure, for trains that have been put into production and are about to be delivered for use or put into operation, the vehicles are operated in an actual working environment, and pure air braking is performed multiple times during the movement to increase the overall temperature of the brake components (such as wheels, brake discs, etc.), simulating the heating conditions of the brake components when the train brakes frequently during actual operation, and providing suitable temperature conditions for subsequent measurements and other operations.

[0049] According to the embodiments of the present disclosure, when the train needs to brake, the air brake system will control the flow direction and pressure of compressed air to press the brake pads tightly against the brake disc, or press the brake shoes against the wheel tread, and use the friction between the brake pads and the brake disc, and between the brake shoes and the wheel tread to hinder the rotation of the wheels, thereby achieving the deceleration and stopping of the train. In this process, the braking force is generated by the brake device driven by air pressure only, without the help of other auxiliary braking methods such as electric braking, which is pure air braking. For example, after the train has been running at a certain speed for a period of time, pure air braking is performed to slow down and stop the train, and then the train is accelerated to the set speed again. After maintaining constant speed for a period of time, pure air braking is performed again, and this cycle is repeated many times. The purpose of this is to allow the brake disc to generate heat due to braking friction, so that the overall temperature of the brake disc is increased.

[0050] In operation S220 , when the temperature of the brake member satisfies a predetermined temperature distribution characteristic, the following operations S221 to S223 are performed.

[0051] According to an embodiment of the present disclosure, the predetermined temperature distribution characteristic may be that the temperature reaches a certain range, or the temperature distribution in different parts conforms to a specific law, etc. For example, the overall temperature distribution on the surface of the brake disc is relatively uniform, and the temperature range is between 150 and 200 degrees Celsius (the specific temperature range may be preset according to factors such as the material properties of the brake disc and the train operation conditions).

[0052] In operation S221, determine the temperature measurement area on the surface of the braking member.

[0053] In operation S222, use an infrared thermometer to measure the temperature of the temperature measurement area, and calibrate the emissivity of the infrared thermometer during the temperature measurement process.

[0054] In operation S222, determine the surface emissivity of the braking member as the emissivity obtained by calibration.

[0055] According to an embodiment of the present disclosure, when the temperature of the braking member satisfies the predetermined temperature distribution characteristic, a specific temperature measurement area is determined on the surface of the braking member. Whether it is an infrared thermometer or other temperature measuring instruments, they all measure the temperature of this temperature measurement area to ensure the accuracy of the measurement position. Use an infrared thermometer to measure the temperature of the selected temperature measurement area, and adjust and calibrate the emissivity of the infrared thermometer. By continuously adjusting the emissivity setting, the temperature measured by the infrared thermometer is made as close as possible to the actual temperature, thereby improving the measurement accuracy.

[0056] According to an embodiment of the present disclosure, infrared thermometers are mainly divided into: short-wave infrared thermometers, mid-wave infrared thermometers, and long-wave infrared thermometers according to the wavelength range they detect. Since the braking member is usually made of metal, and the wheel or brake disc is in a high-speed rotating state in the actual application scenario, the short-wave infrared thermometer is more sensitive to the emissivity of metal oxides, and is suitable for dynamic monitoring of the surface of high-temperature metals, with a faster response and the ability to capture instantaneous temperature changes.

[0057] According to an embodiment of the present disclosure, by measuring the braking component during the train's travel, destructive behaviors such as cutting objects are avoided. This not only maintains the integrity and original working state of the braking component but also directly obtains its temperature and emissivity information during actual operation, ensuring that the measurement results accurately and real-time reflect the true characteristics of the braking component. Compared with the measurement method of cutting the braking component in the related art, the convenience and efficiency of the measurement are improved, and the normal operation rhythm of the train is not affected. Among them, multiple brakings can ensure that the overall temperature of the braking component gradually increases. Compared with the local overheating or uneven temperature distribution that may be caused by single braking or local heating, multiple pure air brakings can allow heat to fully conduct inside the braking component, enabling the braking component to reach a more stable and uniform temperature distribution state to meet the measurement requirements of subsequent emissivity calibration measurement, avoiding temperature measurement errors caused by too rapid temperature drop or uneven temperature distribution, and improving the accuracy of emissivity calibration. Further, by adopting a method of calibrating the emissivity of the infrared thermometer to determine the surface emissivity of the component, it is easy to operate and has a relatively high measurement accuracy.

[0058] According to an embodiment of the present disclosure, the predetermined temperature distribution characteristic is that the difference between the surface temperature and the central temperature of the braking component is less than a predetermined threshold, and the surface temperature and the central temperature are within a predetermined temperature range.

[0059] According to an embodiment of the present disclosure, the surface temperature refers to the temperature of the outer surface of the braking component that is in direct contact with the external environment. The central temperature refers to the temperature at the central part or near the central part inside the braking component. During the braking process of the braking component, heat conducts from the generation site (such as the friction surface) to the inside. Since the internal heat conduction is relatively slow and does not directly exchange heat with the external environment like the surface, the central temperature is usually different from the surface temperature. The central temperature reflects the heat accumulation situation inside the braking component. The difference between the central temperature and the surface temperature can be used to measure the temperature distribution uniformity of the braking component. If the central temperature is too low compared to the surface temperature, it indicates that less heat is absorbed at the center of the braking component and is mainly concentrated on the surface, and the heat has not been fully absorbed and conducted inside, which may be due to a relatively short braking process of the train or a small number of braking times.

[0060] According to an embodiment of the present disclosure, the braking component is usually made of metal, and the metal itself has good thermal conductivity, which makes its heat dissipation speed relatively fast. During the braking process, a large amount of heat is generated due to friction on the braking component, and the surface temperature rises rapidly. However, it takes a certain amount of time for the heat to conduct to the central part, resulting in a significant increase in the difference between the surface temperature and the central temperature. After the braking stops, the surface heat will quickly dissipate to the surrounding environment, not only causing the surface temperature to drop sharply but also increasing the temperature gradient between the surface and the center. This rapid temperature change makes it difficult to capture a relatively stable and representative temperature value during the measurement process, seriously affecting the accuracy of temperature measurement.

[0061] According to an embodiment of the present disclosure, after performing multiple pure air brakings, multiple heat conductions can make the difference between the surface temperature and the central temperature of the braking member reach a relatively small value, less than a predetermined threshold, such as less than 10 degrees Celsius. The surface temperature and the central temperature are close, so that the temperature of the object to be measured is in a relatively high state and the temperature distribution is relatively uniform. Since a certain amount of time is required in the subsequent emissivity calibration process, and the surface temperature of the member to be measured needs to be basically maintained unchanged during this period, if the temperature difference between the surface and the center of the member is too large, the surface temperature will drop rapidly, affecting the emissivity calibration. On the contrary, if the temperature difference between the surface and the center of the member is close, the surface temperature will be maintained in a relatively constant range, which is convenient for subsequent emissivity calibration. The temperature signal received by the infrared thermometer can truly reflect the actual temperature state of the temperature measurement area or even the entire braking member, thus ensuring the accuracy of temperature measurement.

[0062] According to an embodiment of the present disclosure, during the process of increasing the temperature of the wheel and / or the brake disc by performing multiple pure air brakings, the number of brakings needs to be controlled within a reasonable range. If the number of brakings is too large, the surface temperature of the wheel or the brake disc will be too high, which will not only prolong the test time and increase the test cost, but also may cause oxidation discoloration or phase change of the material due to the temperature being higher than the oxidation or phase change temperature of the material, thereby causing a large change in the surface emissivity. If the number of brakings is too small, on the one hand, the temperature difference between the inside and outside of the wheel or the brake disc is too large, resulting in too rapid a change in the surface temperature and inaccurate measurement. On the other hand, in the embodiment of the present disclosure, a short-wave infrared measuring instrument is selected to measure the surface temperature of the wheel or the brake disc. However, when the surface temperature of the wheel or the brake disc is low, the wavelength of the infrared radiation emitted by it may become longer. Since the short-wave infrared measuring instrument can only receive infrared radiation within a specific short-wave wavelength range, the longer-wavelength infrared radiation emitted by the low-temperature object may exceed the wavelength range that the measuring instrument can receive, resulting in the measuring instrument being unable to receive sufficient radiation signals to accurately measure the emissivity of the object surface. Based on this, the short-wave infrared measuring instrument has a higher measurement accuracy in the high-temperature range and a lower measurement accuracy in the low-temperature range. For example, when the temperature is lower than 50 degrees Celsius, accurate temperature values cannot be measured. Therefore, not only the difference between the surface temperature and the central temperature needs to be less than the predetermined threshold, but also the surface temperature and the central temperature need to meet the requirement that the minimum temperature is within a predetermined temperature range, such as higher than 50°C.

[0063] According to an embodiment of the present disclosure, multiple consecutive pure air brakings are performed, and the time interval between two adjacent pure air brakings is greater than a preset time threshold, such as greater than 4 minutes, or greater than 5 minutes, etc.

[0064] According to an embodiment of the present disclosure, multiple brakings can ensure that the overall temperature of the braking component gradually increases. Compared with single braking or local heating, which may cause local overheating or uneven temperature distribution, multiple pure air brakings can allow heat to fully conduct inside the braking component, enabling the braking component to reach a more stable and uniform temperature distribution state, which is conducive to accurately determining the temperature measurement area, avoiding temperature measurement errors caused by uneven temperature, and improving the accuracy of emissivity calibration.

[0065] According to an embodiment of the present disclosure, if the time interval between two adjacent brakings is too short, the heat generated by the new braking will be superimposed on the heat that has not been fully conducted, resulting in uneven heat distribution. On the contrary, a longer and reasonable time interval can allow the heat generated by the first braking to have enough time to fully conduct from the surface of the braking component to the center and other parts, making the temperature distribution of the entire braking component more uniform and avoiding local overheating.

[0066] According to an embodiment of the present disclosure, the braking component may include a wheel and / or a brake disc.

[0067] According to an embodiment of the present disclosure, determining the temperature measurement area on the surface of the braking component includes: determining the temperature measurement area on the surface of the braking component based on the installation position of an infrared thermometer installed near the braking component.

[0068] According to an embodiment of the present disclosure, the measurement range and angle of the infrared thermometer are limited, and it can only measure the surface temperature of an object within its field of view. Therefore, it is necessary to determine the area on the surface of the braking component that it can measure according to the installation position of the infrared thermometer. Specifically, it includes Step 11 to Step 13.

[0069] Step 11, determine the center point based on the intersection point of the extension line of the detection head of the infrared thermometer along the detection direction on the surface of the braking component.

[0070] According to an embodiment of the present disclosure, the detection head of the infrared thermometer emits an infrared radiation detection signal along a specific direction.

[0071] One embodiment of determining the center point is that when the extension line of this detection direction intersects with the surface of the braking component, an intersection point will be generated. This intersection point is selected as the center point for subsequent determination of the temperature measurement area. This center point is in the "directly in front" position of the detection by the infrared thermometer and is representative for measuring the surface temperature of the braking component. Using it as the center point to delimit the temperature measurement area can better reflect the main temperature information detected by the infrared thermometer.

[0072] Another embodiment for determining the center point is to install a cross slide rail composed of two mutually perpendicular slide rails at a suitable position near the braking member. Two measuring devices (positioning components) that can slide freely on the slide rails are respectively installed on the two slide rails. These two positioning components can be equipped with components such as high-precision positioning sensors or pointers for accurately indicating positions. The operator controls one of the positioning components to slide along one slide rail to approach the surface of the braking member until the positioning component (such as a pointer) on the positioning component contacts the surface of the braking member, and records the position data of the positioning component on this slide rail at this time. Control the other positioning component to slide along the slide rail perpendicular to it, also making it approach the surface of the braking member, so that this positioning component contacts the surface of the braking member, and at the same time records the position data of this measuring device on this slide rail at this time. Since the two slide rails are mutually perpendicular, the two perpendicular lines determined by the contact points of the two measuring devices on the surface of the braking member will intersect on the surface of the braking member. According to the position data recorded by these two positioning components, the intersection position of these two perpendicular lines on the surface of the braking member is determined through calculation, that is, the center point. Through this cross-measurement method based on the cross slide rail, the center point can be determined more accurately, providing a reliable basis for determining the temperature measurement area of the infrared thermometer based on this center point in the subsequent process.

[0073] Step 12: Determine the measurement radius according to the straight-line distance between the detection head and the center point.

[0074] According to the embodiments of the present disclosure, in the working principle of the infrared thermometer, its measurement range is related to the distance from the detection head to the target object. For example, if the detection head is closer to the center point, the measurement radius may be relatively smaller, and vice versa. This is a mapping relationship set based on the characteristics of the infrared thermometer and to ensure measurement accuracy. Through this mapping relationship and the distance from the detection head to the center point, the measurement radius is determined, thereby determining a fixed and reasonable area where the infrared thermometer can measure the temperature of this area relatively accurately. Among them, the mapping relationship between the distance from the detection head to the surface of the target object and the measurement range can be determined according to the standard instruction manual of the infrared thermometer.

[0075] Step 13: Determine the temperature measurement area based on the center point and the measurement radius.

[0076] According to an embodiment of the present disclosure, after obtaining the center point and the measurement radius, the temperature measurement area can be determined. Taking the center point as the center and the measurement radius as the radius, a circle is drawn on the surface of the braking member (in the ideal case on a two-dimensional plane, which may vary in actual situations due to factors such as the shape of the braking member, but the principle is similar) or a corresponding area range. This area is the area where the infrared thermometer can effectively measure the temperature. In this way, the specific range measured by the infrared thermometer is clarified, making the temperature measurement more targeted and accurate, and facilitating the analysis and evaluation of the surface temperature of the braking member.

[0077] According to an embodiment of the present disclosure, calibrating the emissivity of the infrared thermometer includes steps 21 to 23.

[0078] Step 21, measure the true temperature of the temperature measurement area.

[0079] According to an embodiment of the present disclosure, the true temperature of the temperature measurement area is measured using a surface thermometer. The surface thermometer selects a high-precision, calibrated standard temperature measurement device, such as a thermocouple thermometer, a resistance thermometer, etc. This measurement method is a contact measurement, which can measure the true temperature of the temperature measurement area more accurately and provide a benchmark for subsequent comparison with the measurement results of the infrared thermometer.

[0080] Step 22, based on the first emissivity set for the infrared thermometer, measure the first temperature of the temperature measurement area.

[0081] According to an embodiment of the present disclosure, an initial emissivity value, that is, the first emissivity, is first set for the infrared thermometer. Then, the infrared thermometer is used to measure the temperature of the same temperature measurement area, and the obtained temperature value is the first temperature. Since the emissivity set at this time may be inaccurate, the first temperature may deviate from the true temperature.

[0082] Step 23, in the case where the first temperature and the true temperature do not meet the predetermined numerical conditions, adjust the first emissivity to the second emissivity. In the case where the second temperature of the temperature measurement area measured based on the second emissivity and the true temperature meet the predetermined numerical conditions, the calibration of the emissivity of the infrared thermometer is completed, where the second emissivity is the calibrated emissivity.

[0083] According to an embodiment of the present disclosure, it is judged whether the first temperature and the true temperature meet the predetermined numerical conditions. The predetermined numerical conditions are a judgment standard set in advance according to factors such as measurement accuracy requirements, for example, the difference between the two is within a certain range, or the ratio of the two is within a certain specific interval, etc.

[0084] According to an embodiment of the present disclosure, if the first temperature and the true temperature do not meet the predetermined numerical conditions, it indicates that the currently set first emissivity is inaccurate and needs to be adjusted. The first emissivity is adjusted to the second emissivity, and then the infrared thermometer is used again to measure the temperature of the temperature measurement area based on the second emissivity, obtaining the second temperature.

[0085] According to an embodiment of the present disclosure, it is determined whether the second temperature and the true temperature meet the predetermined numerical conditions. If they meet, it means that by adjusting the emissivity, the measurement result of the infrared thermometer has been able to reach the accuracy requirement consistent with the true temperature. At this time, the calibration of the emissivity of the infrared thermometer is completed, and the second emissivity is determined as the finally calibrated emissivity. In this way, when measuring the temperature of the braking component using this infrared thermometer subsequently, this calibrated emissivity can be used to obtain a more accurate measurement result.

[0086] According to an embodiment of the present disclosure, in order to ensure the measurement accuracy of the emissivity, it is necessary to ensure that the temperature of the braking component meets the predetermined temperature distribution characteristics during the emissivity measurement, and the temperature of the braking component can be determined whether it reaches the test requirements by means of real-time monitoring of the temperature change of the braking component.

[0087] Figure 3 Schematically shows a flowchart of monitoring the temperature of a braking component during multiple pure air brakings according to an embodiment of the present disclosure. Figure 4A and Figure 4B Schematically show schematic diagrams of a surface temperature measuring instrument installed on the surfaces of a brake shoe and a brake pad according to an embodiment of the present disclosure. Figure 5A and Figure 5B Schematically show schematic diagrams of the relative installation positions of the surface temperature measuring instrument and the braking component according to an embodiment of the present disclosure. The following will describe the surface emissivity measurement method of the embodiment of the present disclosure in conjunction with Figure 3 , Figure 4A , Figure 4B , Figure 5A , Figure 5B .

[0088] As Figure 3 shown, the method for monitoring the temperature of the braking component includes operation S310 to operation S330.

[0089] In operation S310, a surface temperature measuring instrument is arranged on the surface of the brake shoe and / or the brake pad, where the brake shoe rubs against the wheel pair during the pure air braking process, and the brake pad rubs against the brake disc during the pure air braking process.

[0090] According to an embodiment of the present disclosure, the brake shoe and the brake pad are important braking components in the train braking system. As Figure 5A shown, during braking, the brake shoe 402 contacts the tread surface of the wheel 102 and generates frictional force to decelerate the train; asFigure 5B As shown, the brake pad 403 and the brake disc 404 rub against each other to achieve the braking function. In order to be able to use the surface temperature measuring instrument 401 to measure the temperature of these braking components during braking, the surface temperature measuring instrument 401 (such as a thermocouple, a resistance thermometer) is installed on the surface of the brake shoe 402 and / or the brake pad 403.

[0091] It should be noted that the surface temperature measuring instrument 401 cannot be installed on the surface where the brake shoe or the brake pad contacts the wheel or the brake disc to prevent damage to the surface temperature measuring instrument 401. The surface temperature measuring instrument 401 can be installed on the surface that does not contact the wheel or the brake disc. For example Figure 5A the back or side of the brake shoe 402 as shown, and Figure 5B the back or side of the brake pad 403 as shown. During braking, the brake shoe and the brake pad are in direct contact with the component to be measured, and through the heat conduction of the brake shoe and the brake pad themselves, the temperature change caused by braking can be indirectly measured.

[0092] In operation S320, during multiple pure air brakings, multiple sets of first monitored temperatures are collected by using the surface temperature measuring instrument.

[0093] Exemplarily, for the first pure air braking: from the 1st second to the 10th second of the start of braking, the surface temperature measuring instrument collects temperature data every 1 second. These 10 temperature data (such as 50°C, 53°C, 56°C, 58°C, 60°C, 62°C, 65°C, 67°C, 68°C, 70°C in sequence) constitute the first set of first monitored temperatures, which reflects the surface temperature change of the brake shoe or the brake pad during the period from the 1st second to the 10th second in the first pure air braking process. For the second pure air braking: only one temperature value is collected at the 5th second after the start of braking. Assuming this temperature value is 80°C, then this one temperature value constitutes the second set of first monitored temperatures, corresponding to the surface temperature value of the brake shoe or the brake pad at the 5th second in the second pure air braking process. For the third pure air braking: the measuring instrument collects temperature data at the 3rd second, the 6th second, and the 9th second after the start of braking, which are 75°C, 82°C, and 85°C in sequence. These three temperature data form the third set of first monitored temperatures, indicating the surface temperature values of the brake shoe or the brake pad at the 3rd second, the 6th second, and the 9th second in the third pure air braking process.

[0094] According to the embodiments of the present disclosure, during each pure air braking process, a large amount of heat is generated due to the rubbing between the brake shoe 402 and the wheel 102, and between the brake pad 403 and the brake disc 404, resulting in an increase in the temperature of the brake shoe 402 and the brake pad 403. The surface temperature measuring instrument arranged on their surfaces collects temperature data in real time, and each set of first monitored temperatures corresponds to the surface temperature value of the brake shoe or the brake pad at a certain moment or a certain time period during a pure air braking process.

[0095] Figure 6A Schematically shows the overall temperature change curve of the brake shoe after multiple pure air brakings according to an embodiment of the present disclosure. Figure 6B Schematically shows the local temperature change curve of the brake shoe after multiple pure air brakings according to an embodiment of the present disclosure. Among them, Figure 6B The shown temperature change curve is Figure 6A The local enlarged view at the dashed box in

[0096] As Figure 6A and Figure 6B shown, the temperature change curve of the thermocouple measuring the brake shoe during 19 tread brakings of a certain type of subway vehicle is shown. It can be seen that the thermocouple in the brake shoe can reflect the temperature value and its change characteristics of the near-friction surface of the brake shoe in real time, and indirectly reflects the temperature value and its change of the wheel tread surface. By observing this temperature curve in real time, the number of pure air brakings can be adjusted to control the wheel temperature. As Figure 6A shown, if it is judged that the wheel temperature has met the temperature range of the predetermined temperature distribution characteristics according to the temperature rise situation, the increase in the number of brakings can be stopped and the heating can be stopped. Since the braking process of the brake pad and the brake disc is similar to the above process, its temperature change characteristics are similar and will not be elaborated here.

[0097] In operation S330, according to multiple sets of first monitored temperatures, determine whether the temperature of the braking member meets the predetermined temperature distribution characteristics.

[0098] According to an embodiment of the present disclosure, by analyzing and processing multiple sets of first monitored temperatures collected, these parameters are compared with the predetermined temperature distribution characteristics. If the analysis result shows that the temperature distribution of the braking member reflected by these temperature data meets the predetermined temperature distribution characteristics, it means that the temperature state of the braking member is normal and meets the requirements; on the contrary, if it does not meet the predetermined temperature distribution characteristics, it may mean that there are problems such as local overheating and uneven heating of the braking member. Analyzing and processing multiple sets of first monitored temperatures can be calculating the average value, maximum value, minimum value, temperature gradient, etc. of the temperature, which will not be elaborated here.

[0099] Figure 7 Schematically shows a flowchart for monitoring the temperature of a braking member under multiple pure air brakings according to another embodiment of the present disclosure.

[0100] As Figure 7 shown, the method for monitoring the temperature of the braking member includes operation S710 to operation S730.

[0101] In operation S710, based on the historical measurement data for the braking member, assign a reference emissivity to the infrared thermometer.

[0102] In operation S720, during multiple pure air brakings, based on the reference emissivity, the temperature of the wheel and / or brake disc is measured using an infrared thermometer to obtain multiple sets of second monitored temperatures.

[0103] In operation S730, based on the multiple sets of second monitored temperatures, it is determined whether the temperature of the braking component satisfies the predetermined temperature distribution characteristics.

[0104] According to an embodiment of the present disclosure, an emissivity value is estimated based on the states of the wheel tread and brake disc surfaces (including materials, textures, roughness, colors, etc.) and historical measurement data as the reference emissivity. The temperature of the wheel tread or brake disc surface is directly measured using an infrared thermometer installed on the vehicle to obtain multiple sets of second monitored temperatures that can characterize the temperature change of the wheel tread or brake disc surface. Although there is an error between the estimated emissivity and the true emissivity, on the one hand, the temperature required for measuring the emissivity is in a relatively large range (for subway vehicles, the temperature for measuring the emissivity of the wheel and brake disc surfaces can be selected between 60 - 300 °C). On the other hand, the test temperature difference caused by inaccurate emissivity setting is generally not large (for example, for a surface with a true temperature of 300 °C, if the true emissivity is 0.75 and the estimated emissivity is 0.5, the measured temperature may be around 260 °C). Therefore, the temperature value measured by the infrared thermometer with the estimated emissivity can approximately reflect the change of the true temperature of the wheel and brake disc surfaces, thus helping to formulate a braking strategy for emissivity measurement. Figure 8A Schematically shows a schematic diagram of the temperature field simulation model of the wheel and axle during the tread braking process according to an embodiment of the present disclosure. Figure 8B Schematically shows a schematic diagram of the temperature field simulation model of the brake disc, wheel, and axle during the disc braking process according to an embodiment of the present disclosure. Figure 9 Schematically shows a flowchart of the method for determining the target braking strategy according to the simulation model according to an embodiment of the present disclosure.

[0105] As Figure 9 shown, the method for determining the target braking strategy according to the simulation model includes operation S910 to operation S930.

[0106] In operation S910, a braking simulation model for the wheel and / or brake disc is established.

[0107] According to an embodiment of the present disclosure, as Figure 8A and Figure 8B shown, through a computer program and related algorithms, a model that can simulate various physical phenomena of the wheel and / or brake disc during braking is constructed. This model takes into account various factors such as friction force, heat generation and conduction, and material properties during braking to simulate the actual braking process as accurately as possible.

[0108] In operation S920, based on the braking simulation model, the pure air braking process of the wheel and / or brake disc under N braking strategies is simulated, and N sets of simulated temperature change data of the wheel and / or brake disc corresponding to the N braking strategies are output.

[0109] According to an embodiment of the present disclosure, using the established braking simulation model, a computer simulation of the pure air braking process of the wheel and / or brake disc under different braking strategies is performed. Wherein, N is a positive integer greater than or equal to 1. Each braking strategy has its specific parameter settings, such as the magnitude of the braking pressure, the time interval for applying the brake, etc. During the simulation process, the model calculates and outputs the data of the temperature change of the wheel and / or brake disc over time under this braking strategy, so that N sets of simulated temperature change data corresponding to the N braking strategies are obtained.

[0110] According to an embodiment of the present disclosure, multiple braking strategies can be formulated based on different time intervals. Exemplarily, the braking strategies may include: Strategy One, Strategy Two, Strategy Three, and Strategy Four.

[0111] Strategy One: Apply the brake at the same time interval.

[0112] During the train operation, the first braking instruction is issued at the 3rd minute, the second braking instruction is issued after the 6th minute, the third braking instruction is issued after the 9th minute, and so on, maintaining a stable braking force output. This cycle continues until the train stops steadily at the platform.

[0113] Strategy Two: Apply the brake at random time intervals, but ensure that the average braking time interval is maintained within a certain range.

[0114] The preset average braking time interval is set to 5 minutes, but the braking time interval is random each time. The first braking interval is 3 minutes, the next is 8 minutes, and the next is 6 minutes, etc. Simulate the braking situation when the vehicle starts and stops frequently.

[0115] Strategy Three: Apply the brake at gradually shortening time intervals.

[0116] At the initial stage of train braking, the brake is applied once every 10 minutes. After running for a period of time, it is shortened to once every 8 minutes, and after another period of time, it becomes once every 6 minutes. As the braking process progresses, the time interval gradually decreases, which can gradually increase the braking intensity and simulate the braking strategy in a scenario that requires rapid deceleration.

[0117] Strategy Four: Apply the brake at gradually lengthening time intervals.

[0118] When the train starts braking, braking is applied every 3 minutes. When the speed drops to a certain level, the braking time interval is extended to 5 minutes. When the speed further drops to a certain level, the braking time interval is further extended to 8 minutes. This is applicable to the braking process before the train enters the station.

[0119] Figure 10A Schematically shows a graph of the overall temperature change of the wheel tread after multiple pure air brakings according to an embodiment of the present disclosure. Figure 10B Schematically shows a graph of the local temperature change of the wheel tread after multiple pure air brakings according to an embodiment of the present disclosure. Among them, Figure 10B The shown temperature change graph is Figure 10A The local enlarged view at the dashed box in

[0120] From Figure 10A and Figure 10B it can be seen that through simulation calculation, the temperature change of the wheel tread under different braking conditions can be obtained quickly and conveniently. Therefore, when the temperature requirement for emissivity measurement is determined, a braking strategy that meets the requirement can be determined through simulation calculation for application to the actual working conditions of the vehicle. Since the braking process with the brake disc is similar to the above process and its temperature change characteristics are similar, it will not be elaborated here.

[0121] In operation S930, based on N sets of simulated temperature change data, a target braking strategy is determined from N braking strategies.

[0122] According to an embodiment of the present disclosure, analyzing these N sets of simulated temperature change data, the most suitable braking strategy that meets the expectation is selected from N braking strategies as the target braking strategy according to preset conditions. For example, a strategy that can make the temperature of the wheel and / or brake disc rise relatively gently, does not exceed the safety temperature threshold, and can ensure a good braking effect at the same time is selected as the target braking strategy.

[0123] According to an embodiment of the present disclosure, by simulating the temperature change under different braking strategies through a simulation experiment, a target braking strategy that can control the temperature of the wheel and brake disc within a reasonable range during braking and can achieve a good braking effect at the same time can be found, thereby optimizing the braking performance of the train and ensuring that the train can stop safely and quickly. Avoid the situation where unreasonable braking strategies cause excessive wear or damage to braking components, increasing the frequency and cost of maintenance and replacement. During the actual research and development process of the train braking system, through computer simulation, multiple braking strategies can be quickly tested in a virtual environment without conducting a large number of actual tests, saving research and development time and cost.

[0124] The embodiments of the present disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although the embodiments have been described separately above, this does not mean that the measures in each embodiment cannot be used advantageously in combination. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, and all such substitutions and modifications should fall within the scope of the present disclosure.

Claims

1. A surface emissivity measurement method, comprising: Performing multiple pure air brakings during the train's movement to raise the overall temperature of the braking components of the train; When the temperature of the braking components satisfies a predetermined temperature distribution characteristic, perform the following operations: Determine the temperature measurement area on the surface of the braking components; Use an infrared thermometer to measure the temperature of the temperature measurement area, and during the temperature measurement process, calibrate the emissivity of the infrared thermometer; Determine the surface emissivity of the braking components as the emissivity obtained by calibration.

2. The method according to claim 1, wherein: The predetermined temperature distribution characteristic is that the difference between the surface temperature and the central temperature of the braking components is less than a predetermined threshold, and the surface temperature and the central temperature are within a predetermined temperature range.

3. The method according to claim 1, wherein Performing multiple pure air brakings includes: Performing multiple consecutive pure air brakings, and the time interval between two adjacent pure air brakings is greater than a preset time threshold.

4. The method according to any one of claims 1-3, wherein, The braking components include wheels and / or brake discs.

5. The method according to claim 4, further comprising: Arranging surface temperature measuring instruments on the surface of brake shoes and / or brake pads, wherein the brake shoes rub against the wheels during pure air braking, and the brake pads rub against the brake discs during pure air braking; During the multiple pure air brakings, use the surface temperature measuring instruments to collect multiple sets of first monitored temperatures; Based on the multiple sets of first monitored temperatures, determine whether the temperature of the braking components satisfies the predetermined temperature distribution characteristic.

6. The method according to claim 4, further comprising: Establishing a braking simulation model for the wheels and / or the brake discs; Based on the braking simulation model, simulate the pure air braking process of the wheels and / or the brake discs under N braking strategies, and output N sets of simulated temperature change data corresponding to the wheels and / or the brake discs under the N braking strategies; Based on the N sets of simulated temperature change data, determine the target braking strategy from the N braking strategies.

7. The method according to claim 4, further comprising: Assigning a reference emissivity to the infrared thermometer based on historical measurement data for the braking components; During the multiple pure air brakings, based on the reference emissivity, use the infrared thermometer to measure the temperature of the wheels and / or the brake discs to obtain multiple sets of second monitored temperatures; Based on the multiple sets of second monitored temperatures, determine whether the temperature of the braking components satisfies the predetermined temperature distribution characteristic.

8. The method according to claim 1, wherein Calibrating the emissivity of the infrared thermometer includes: Measuring the true temperature of the temperature measurement area; Based on a first emissivity set for the infrared thermometer, measuring the first temperature of the temperature measurement area; In the case where the first temperature and the true temperature do not meet the predetermined numerical conditions, adjust the first emissivity to a second emissivity. When the second temperature of the temperature measurement area measured based on the second emissivity and the true temperature meet the predetermined numerical conditions, complete the calibration of the emissivity of the infrared thermometer, where the second emissivity is the emissivity obtained by calibration.

9. The method according to claim 1, wherein Determining the temperature measurement area on the surface of the braking member includes: Based on the installation position of the infrared thermometer installed near the braking member, determine the temperature measurement area on the surface of the braking member.

10. The method according to claim 1, wherein determining the temperature measurement area on the surface of the braking member based on the installation position of the infrared thermometer installed near the braking member includes: Based on the intersection point of the extension line of the detection head of the infrared thermometer along the detection direction on the surface of the braking member, determine the center point; According to the straight-line distance between the detection head and the center point, determine the measurement radius; Based on the center point and the measurement radius, determine the temperature measurement area.

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