Fault monitoring method and system for vehicle-mounted optical cable

Abstract

The invention relates to a fault monitoring method and system for a vehicle-mounted optical cable, and the method comprises the steps: segmenting the vehicle-mounted optical cable according to the arrangement position of the vehicle-mounted optical cable in a vehicle body, and forming a plurality of segment intervals and segment nodes; performing temperature detection at each segment node position outside the vehicle-mounted optical cable, and performing fitting by using multi-point temperature detection information to form a fitting temperature curve outside the vehicle-mounted optical cable; detecting the temperature of the optical fiber in the vehicle-mounted optical cable by using an optical fiber temperature measurement technology to form an actual temperature curve in the vehicle-mounted optical cable; comparing the change trends of the fitting temperature curve and the actual temperature curve in real time, and judging whether the vehicle-mounted optical cable breaks down or not; and comparing the fitting temperature curve with the actual temperature curve in an equal proportion, determining a segment interval where the fault occurs, and calculating the distance from the fault point to the nearest segment node. Real-time monitoring and fault diagnosis of the vehicle-mounted optical cable are realized through segmented monitoring, temperature curve fitting, internal and external temperature curve comparison and fault positioning.

Description

Technical Field

[0001] The present invention relates to the technical field of monitoring vehicle-mounted optical cables, and in particular to a fault monitoring method and system for vehicle-mounted optical cables. Background Art

[0002] With the development of automobile intelligence and networking, optical cables play an increasingly important role in automobile communication systems. Due to the complex vehicle operating environment, optical cables are easily affected by mechanical damage, high temperature, electromagnetic interference and other factors, leading to failures. Once an optical cable fails, it will seriously affect the normal operation of the vehicle.

[0003] Generally, when an optical cable fails, the short circuit caused by the failure will cause the temperature at the fault location to rise sharply. Taking advantage of this feature, the existing technology uses optical fiber temperature measurement technology to monitor the temperature of the optical cable along the length direction, so as to determine the location of the fault. However, the existing optical fiber temperature measurement technology cannot be directly applied to the measurement field of vehicle-mounted optical cables. There are two main problems: 1. When displaying the fault location, the fiber optic temperature measurement technology can only determine the distance between the fault and the test equipment. However, in the vehicle-mounted optical cable, its layout is determined according to the structure of the vehicle body and the needs of the electrical equipment. The layout of the vehicle-mounted optical cable is more complicated than that of the traditional transmission optical cable. It is impossible to accurately determine the location of the fault only by the length distance. During maintenance, if the fault location cannot be accurately determined, all parts covering the vehicle-mounted optical cable in the vehicle body need to be disassembled, which makes maintenance difficult and costly.

[0004] 2. When the vehicle-mounted optical cable is actually used, the temperature changes of the vehicle-mounted optical cables in different installation positions are also different. For example, the temperature of the vehicle-mounted optical cable near the engine will rise rapidly after the engine is started. If the fault is judged only based on the single monitoring indicator of optical fiber temperature measurement technology, on the one hand, the judgment threshold cannot be accurately set. On the other hand, due to the influence of external environmental factors, there will also be a high misjudgment rate. Summary of the invention

[0005] To this end, the technical problem to be solved by the present invention is to overcome the problems of high misjudgment rate and inability to accurately locate the vehicle-mounted optical cable that cannot be overcome by only using optical fiber temperature measurement technology in the prior art due to environmental factors. A fault monitoring method and system for a vehicle-mounted optical cable are provided, which realizes real-time monitoring and fault diagnosis of the vehicle-mounted optical cable through segmented monitoring, temperature curve fitting, internal and external temperature curve comparison and fault location.

[0006] In order to solve the above technical problems, the present invention provides a fault monitoring method for a vehicle-mounted optical cable, comprising the following steps: The vehicle-mounted optical cable is segmented according to the layout position in the vehicle body to form a plurality of segment intervals and segment nodes; Perform temperature detection at each segment node position outside the vehicle optical cable, and use multi-point temperature detection information to fit a fitting temperature curve outside the vehicle optical cable; The optical fiber temperature measurement technology is used inside the vehicle optical cable to detect the temperature of the optical fiber and form the actual temperature curve inside the vehicle optical cable; Compare the changing trends of the fitted temperature curve and the actual temperature curve in real time. When it is found that the heating rate of the actual temperature curve at a certain position exceeds the heating rate of the fitted temperature curve, it is judged that the vehicle optical cable has a fault at that position. Otherwise, it is judged that the vehicle optical cable is in normal use. After determining that the on-board optical cable has a fault, the fitted temperature curve and the actual temperature curve are compared in proportion, and the segmented node position of the external temperature detection module is mapped to the actual temperature curve. Based on this, the segmented interval where the fault occurs is determined and the distance from the fault point to the nearest segmented node is calculated.

[0007] In one embodiment of the present invention, the segmentation standards of the vehicle-mounted optical cable include: The vehicle body components are grouped based on each other, and a segment node is set between two adjacent groups of vehicle body components, wherein the vehicle body components are independently detachable components; In each group of vehicle body components, a segment node is arranged at a bending position of each vehicle-mounted optical cable; In each group of vehicle body components, when the vehicle-mounted optical cable has no bend, a plurality of segment nodes are arranged with equidistant lengths.

[0008] In one embodiment of the present invention, the steps of fitting the temperature curve of the exterior of the vehicle optical cable by using the multi-point temperature detection information are as follows: Assuming segment node positions x 1, x 2… x n Measured temperatures T1, T2…T n Construct a polynomial regression model: T ( x )= β 0+ β 1 x + β 2 x 2 + β 3 x 3 +…+ β k x k + ε ; in: T ( x ) is the temperature with respect to position x Function of β 0, β 1, β 2,… β k are the coefficients of the polynomial; ε is the error term, which represents the random error that cannot be explained by the model; Collect location points x i and the corresponding temperature measurement value T i , the location point x i Convert to polynomial features and get the feature matrix X: ; Solving for the coefficients of a polynomial using the least squares method β 0, β 1, β 2,… β k To minimize the residual sum of squares, the solution of the least squares method can be obtained by the following formula: ; Where: X is the feature matrix, each row contains x i The power of ; T is a column vector of temperature measurements; are estimates of the polynomial coefficients.

[0009] In one embodiment of the present invention, infrared temperature measurement technology is used to perform contactless temperature detection at each segment node position outside the vehicle-mounted optical cable.

[0010] In one embodiment of the present invention, temperature detection is performed on each segment node position outside the vehicle-mounted optical cable under different ambient temperatures, a model of the impact of ambient temperature on the temperature of the optical cable is established, and the formed fitting temperature curve is dynamically corrected in combination with the ambient temperature.

[0011] In one embodiment of the present invention, a distributed optical fiber temperature measurement technology is used in a vehicle-mounted optical cable to obtain the temperature distribution along the optical fiber path by measuring the intensity change of the optical signal of Rayleigh scattering or Raman scattering in the optical fiber.

[0012] In one embodiment of the present invention, when comparing the changing trends of the fitted temperature curve and the actual temperature curve in real time, a threshold is set to determine whether the temperature difference between the fitted temperature curve and the actual temperature curve exceeds the normal range, wherein: the threshold is determined by the temperature change trend when an actual simulated vehicle optical cable fails.

[0013] In one embodiment of the present invention, when the fitted temperature curve and the actual temperature curve are compared in proportion, a visualization processing method is used to draw the fitted temperature curve and the actual temperature curve on the same scale.

[0014] In one embodiment of the present invention, the following steps are also included: When it is determined that the on-board optical cable fails, the time and location of the failure are recorded, and an alarm signal is sent to the central control system; Establish a fault database and collect data on each fault that occurs.

[0015] In order to solve the above technical problems, the present invention also provides a vehicle-mounted optical cable fault monitoring system, which is used to implement the above vehicle-mounted optical cable fault monitoring method, comprising: A segmentation module is used to divide the vehicle-mounted optical cable into multiple segment intervals according to the layout position in the vehicle body, and define segment nodes between each segment; The external temperature detection module is arranged at each segment node, and is used to detect the temperature outside the vehicle optical cable and collect multi-point temperature data to form a fitting temperature curve; The internal temperature detection module is integrated inside the vehicle-mounted optical cable and uses optical fiber temperature measurement technology to detect the optical fiber temperature and generate an actual temperature curve; The monitoring and analysis module is used to compare the changing trends of the fitted temperature curve and the actual temperature curve in real time, and identify the potential fault location by analyzing the difference between the two. When it is found that the heating rate of the actual temperature curve at a certain location exceeds the heating rate of the fitted temperature curve, it is judged that the vehicle optical cable has a fault at that location. Otherwise, it is judged that the vehicle optical cable is in normal use. After confirming the fault, the fault location module can map the segmented nodes of the external temperature detection module to the actual temperature curve according to the proportional relationship between the fitted temperature curve and the actual temperature curve, thereby determining the specific segmented interval where the fault occurs and its precise distance from the nearest segmented node.

[0016] The above technical solution of the present invention has the following advantages compared with the prior art: The invention discloses a fault monitoring method and system for a vehicle-mounted optical cable, which realizes real-time monitoring and fault diagnosis of the vehicle-mounted optical cable through segmented monitoring, temperature curve fitting, internal and external temperature curve comparison and fault location.

[0017] Among them: In view of the problem that the prior art only uses optical fiber temperature measurement technology in vehicle-mounted optical cables and cannot overcome the high misjudgment rate caused by environmental factors, the present invention combines external temperature detection and internal optical fiber temperature measurement technology to judge the fault by comparing the changing trends of the internal and external temperatures at a certain position. It is more accurate than traditional single temperature detection or temperature difference detection, and can improve the accuracy of fault judgment. In addition, during actual monitoring, it is impossible to continuously measure the external temperature of the vehicle-mounted optical cable. In order to compare it with the actual temperature curve generated by the optical fiber temperature measurement technology, the present application adopts point measurement to generate a continuous fitting temperature curve through fitting.

[0018] In view of the problem that the fiber optic temperature measurement technology used in the prior art cannot accurately locate the fault position in the vehicle body, the present invention adopts a proportional comparison method to calibrate the node positions in the external fitting temperature curve on the internal actual temperature curve. When the actual temperature curve shows that a fault occurs at a certain position, the segmented interval where the fault occurs can be determined in the fitting temperature curve accordingly, and the distance between the fault point and the nearest segmented node can be calculated according to the proportion, which is very helpful for quickly repairing the fault. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein: Figure 1 is a flow chart of a fault monitoring method for a vehicle-mounted optical cable of the present invention; Figure 2 It is a structural block diagram of the fault monitoring system of the vehicle-mounted optical cable of the present invention. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0021] Example 1

[0022] There are two main aspects to consider when monitoring faults in vehicle-mounted optical cables: one is to determine whether a fault occurs, and the other is to determine the exact location of the fault. Compared with traditional directly buried or overhead optical cables, vehicle-mounted optical cables are short in overall length, and the lines arranged in the vehicle body are mostly curved according to the distribution of electrical equipment in the vehicle. In addition, their temperature changes greatly due to the influence of vehicle functions depending on the location of the arrangement. Therefore, as mentioned above, the optical fiber temperature detection technology used in directly buried or overhead optical cables using the existing technology is not applicable to determine faults in vehicle-mounted optical cables.

[0023] Reference Figure 1As shown, in view of the above problems, the present invention discloses a fault monitoring method for a vehicle-mounted optical cable, comprising: Step 1: segment the vehicle-mounted optical cable according to its layout position in the vehicle body to form multiple segment intervals and segment nodes.

[0024] Specifically, in actual applications, when setting segmentation intervals and segmentation nodes, segmentation standards are formulated according to actual conditions: The vehicle body components are grouped based on each other, and a segmentation node is set between two adjacent groups of vehicle body components, wherein the vehicle body components are independently detachable components. In the present embodiment, the purpose of segmenting the vehicle optical cable is to accurately find the fault point when judging the fault, and to repair the fault point. The independently detachable vehicle body components are used as segmentation nodes. When it is judged that a certain area between two segmentation nodes has a fault, the vehicle body components in the area can be directly disassembled, and the vehicle optical cable in the area can be repaired without disassembling the vehicle body components in other positions. This can reduce the maintenance and disassembly work.

[0025] In each group of vehicle body components, multiple segment nodes can be set according to the actual wiring situation. For example, a segment node is set at the bending position of each vehicle-mounted optical cable. This is because the vehicle-mounted optical cable is prone to bending at the bending position, which may lead to short circuits. When the vehicle-mounted optical cable is not bent, in order to ensure the accuracy of the test, multiple segment nodes can also be set at equidistant lengths. For example, in actual wiring, a segment node is set every 10 to 20 cm. Specifically, the more segment nodes are set, the more accurate the fitted temperature measurement curve constructed, and thus, the more accurate the fault occurrence and fault location monitored.

[0026] Step 2: Perform temperature detection at each segment node position outside the vehicle optical cable, and use multi-point temperature detection information to fit a fitting temperature curve outside the vehicle optical cable.

[0027] During actual monitoring, it is impossible to continuously measure the external temperature of the vehicle-mounted optical cable. In order to compare it with the actual temperature curve generated by the optical fiber temperature measurement technology, this application adopts a point measurement method to generate a continuous fitting temperature curve through fitting.

[0028] Specifically, in order to improve the accuracy of fitting the temperature curve, in this embodiment, a polynomial regression model is established, and the model's fitting ability for nonlinear data is enhanced by introducing high-order terms of independent variables. x 1, x 2… x n Measured temperatures T1, T2…T n Construct a polynomial regression model: T ( x )= β 0+ β 1 x + β 2 x 2 + β 3 x 3 +…+ β k x k + ε in: T ( x ) is the temperature with respect to position x Function of β 0, β 1, β 2,… β k are the coefficients of the polynomial; ε is the error term, which represents the random error that cannot be explained by the model; Using the above polynomial regression model, collect location points x i and the corresponding temperature measurement value T i , that is, collecting the actual measured temperature at each segment node position, for example: in this embodiment, the following data points are set: x 1. Measurement temperature 20℃, x 2Measurement temperature 22℃, x 3. Measurement temperature: 25℃, x 4Measurement temperature 28℃, x 5. Measurement temperature: 30℃; The location point x i Convert to polynomial features and get the feature matrix X and temperature vector T:

[0029] Right now:

[0030] Solving for the coefficients of a polynomial using the least squares method β 0, β 1, β 2,… β k To minimize the residual sum of squares, the solution of the least squares method can be obtained by the following formula:

[0031] Where: X is the feature matrix, each row contains x i The power of ; T is a column vector of temperature measurements; are estimates of the polynomial coefficients.

[0032] After calculation, the fitting quadratic polynomial can be obtained: T ( x )=19.8+2.2 x +0.5 x 2 A fitting temperature curve can be drawn based on the quadratic polynomial.

[0033] Specifically, when measuring the temperature of each segment node outside the vehicle-mounted optical cable, infrared temperature measurement technology is used, and infrared temperature measurement sensors are used to perform non-contact temperature detection, which can reduce the temperature impact of the vehicle-mounted optical cable of the temperature measurement sensor and further improve the measurement accuracy.

[0034] Specifically, when an infrared temperature sensor is used to measure the actual temperature of the vehicle optical cable, because it is a non-contact measurement, the actual temperature measured will be affected by the ambient temperature, resulting in a certain deviation. Therefore, in order to ensure that the temperature measured in this embodiment is the actual temperature outside the vehicle optical cable, when constructing a fitting temperature curve to collect data, the influence of the ambient temperature must also be considered; Therefore, in order to eliminate the influence of ambient temperature, temperature detection is carried out on each segment node position outside the vehicle-mounted optical cable under different ambient temperatures, a model of the influence of ambient temperature on the temperature of the optical cable is established, and the formed fitting temperature curve is dynamically corrected in combination with the ambient temperature.

[0035] Step 3: Use optical fiber temperature measurement technology in the vehicle-mounted optical cable to detect the temperature of the optical fiber and form an actual temperature curve inside the vehicle-mounted optical cable.

[0036] Specifically, fiber optic temperature measurement technology mainly measures temperature based on the changes in the physical properties of light when it propagates in the optical fiber. Common fiber optic temperature measurement technologies include: Distributed Temperature Sensing (DTS): The temperature distribution along the optical fiber path is obtained by measuring the changes in the intensity of the optical signal caused by Rayleigh scattering or Raman scattering in the optical fiber.

[0037] Fiber Bragg Grating (FBG): Temperature is measured by measuring the change in wavelength of light reflected by a fiber Bragg grating.

[0038] In this embodiment, distributed fiber temperature measurement (DTS) technology is used to monitor the temperature change of the vehicle-mounted optical cable: the optical fiber in the vehicle-mounted optical cable is directly used as a fiber optic sensor, the laser is connected to one end of the optical fiber to ensure that the output power and wavelength of the laser meet the requirements, and the photodetector is connected to the other end of the optical fiber to ensure that the detector can accurately receive the returned optical signal; a data acquisition card is used to collect the optical signal returned from the optical fiber, and the optical signal is converted into temperature data through a Raman scattering signal processing algorithm, and the temperature data is integrated to form an actual temperature curve.

[0039] Step 4: Compare the changing trends of the fitted temperature curve and the actual temperature curve in real time. When it is found that the heating rate of the actual temperature curve at a certain position exceeds the heating rate of the fitted temperature curve, it is judged that the vehicle optical cable has a fault at that position. Otherwise, it is judged that the vehicle optical cable is in normal use.

[0040] In this embodiment, in order to solve the problem that the existing technology only uses optical fiber temperature measurement technology in vehicle-mounted optical cables and cannot overcome the high misjudgment rate caused by environmental factors, external temperature detection and internal optical fiber temperature measurement technology are combined to judge the fault by comparing the changing trends of the internal and external temperatures at a certain position. This is more accurate than traditional single temperature detection or temperature difference detection, and can improve the accuracy of fault judgment.

[0041] In practical applications, temperature changes are mainly caused by two factors, changes in external ambient temperature and changes in temperature caused by internal short circuits. When the external ambient temperature changes, because the on-board optical cable has a certain thermal insulation effect, the heating rate of the fitting temperature curve constructed by external detection will definitely be greater than the heating rate of the actual internal temperature curve. At this time, due to the difference in heating rates, a certain temperature difference is also formed. However, in this case, the fault will not be judged to have occurred, thereby reducing the misjudgment of faults caused by environmental changes. When the temperature changes due to an internal short circuit, because the on-board optical cable has a certain thermal insulation effect, at the location where the fault occurs, the heating rate of the actual internal temperature curve will definitely be greater than the heating rate of the fitting temperature curve constructed by external detection. Therefore, by detecting this situation, it can be determined that a short circuit has occurred in the on-board optical cable at this location.

[0042] Specifically, in the existing data statistics, there will be no other situation that causes the heating rate of the actual internal temperature curve to be greater than the heating rate of the fitting temperature curve constructed by external detection. As long as this situation occurs, it can be determined that the vehicle optical cable has completed a short circuit fault. However, in actual applications, in order to reduce the misjudgment rate of faults, when comparing the changing trends of the fitting temperature curve and the actual temperature curve in real time, a threshold is set to determine whether the temperature difference between the fitting temperature curve and the actual temperature curve exceeds the normal range, where: the threshold is determined by the temperature change trend of the actual simulated vehicle optical cable when a fault occurs.

[0043] Step 5. After determining that the on-board optical cable has a fault, compare the fitted temperature curve and the actual temperature curve in proportion. By comparing the proportional relationship between the fitted temperature curve and the actual temperature curve, map the segmented node position of the external temperature detection module to the actual temperature curve, and determine the specific segmented interval where the fault occurs and calculate the distance from the fault point to the nearest segmented node.

[0044] In view of the problem that the fiber optic temperature measurement technology used in the prior art cannot accurately locate the fault position in the vehicle body, this embodiment adopts a proportional comparison method to calibrate the node positions in the external fitting temperature curve on the internal actual temperature curve. When the actual temperature curve shows that a fault occurs at a certain position, the segmented interval where the fault occurs can be determined in the fitting temperature curve accordingly, and the distance between the fault point and the nearest segmented node can be calculated according to the proportion, which is very helpful for quickly repairing the fault.

[0045] Specifically, when comparing the fitted temperature curve and the actual temperature curve in proportion, a visual processing method is used to draw the fitted temperature curve and the actual temperature curve on the same scale, and a graphical user interface is used to display the two temperature curves and their corresponding relationship, so as to facilitate intuitive judgment by operators and to make intuitive comparisons, thereby quickly determining the distance between the fault location and the segmentation node. After positioning, it is only necessary to remove the vehicle body components between the two segmentation nodes at the fault location. After finding the corresponding segmentation node, the corresponding proportional calculation can quickly find the fault location, open the skylight at the fault location, and repair the on-board optical cable where the fault occurred.

[0046] Specifically, in practical application, it also includes: Step 6. Fault recording and alarm: record the time and location information of the fault, send an alarm signal to the central control system, establish a fault database, and collect data on each fault for subsequent analysis and improvement.

[0047] Example 2

[0048] Reference Figure 2As shown, the present invention further discloses a vehicle-mounted optical cable fault monitoring system based on the above-mentioned embodiment 1, comprising: A segmentation module is used to divide the vehicle-mounted optical cable into multiple segment intervals according to the layout position in the vehicle body, and define segment nodes between each segment; The external temperature detection module is arranged at each segment node, and is used to detect the temperature outside the vehicle optical cable and collect multi-point temperature data to form a fitting temperature curve; The internal temperature detection module is integrated inside the vehicle-mounted optical cable and uses optical fiber temperature measurement technology to detect the optical fiber temperature and generate an actual temperature curve; The monitoring and analysis module is used to compare the changing trends of the fitted temperature curve and the actual temperature curve in real time, and identify the potential fault location by analyzing the difference between the two. When it is found that the heating rate of the actual temperature curve at a certain location exceeds the heating rate of the fitted temperature curve, it is judged that the vehicle optical cable has a fault at that location. Otherwise, it is judged that the vehicle optical cable is in normal use. After confirming the fault, the fault location module can map the segmented nodes of the external temperature detection module to the actual temperature curve according to the proportional relationship between the fitted temperature curve and the actual temperature curve, thereby determining the specific segmented interval where the fault occurs and its precise distance from the nearest segmented node.

[0049] The fault monitoring system for the vehicle-mounted optical cable disclosed in the embodiment of the present invention realizes real-time monitoring and fault diagnosis of the vehicle-mounted optical cable through segmented monitoring, temperature curve fitting, internal and external temperature curve comparison and fault location. The technical effect that can be achieved is as described in the above embodiment 1 and will not be repeated here.

[0050] Specifically, in actual application, a fault recording and alarm module is also set up to record the time and location information of the fault, send an alarm signal to the central control system, establish a fault database, and collect data on each fault for subsequent analysis and improvement.

[0051] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0052] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0053] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0054] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0055] Obviously, the above embodiments are merely examples for the purpose of clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A method for fault monitoring of a vehicle-mounted optical cable, characterized in that: The following steps are involved: The vehicle-mounted optical cable is segmented according to the layout position in the vehicle body to form a plurality of segment intervals and segment nodes; Perform temperature detection at each segment node position outside the vehicle optical cable, and use multi-point temperature detection information to fit a fitting temperature curve outside the vehicle optical cable; The optical fiber temperature measurement technology is used inside the vehicle optical cable to detect the temperature of the optical fiber and form the actual temperature curve inside the vehicle optical cable; Compare the changing trends of the fitted temperature curve and the actual temperature curve in real time. When it is found that the heating rate of the actual temperature curve at a certain position exceeds the heating rate of the fitted temperature curve, it is judged that the vehicle optical cable has a fault at that position. Otherwise, it is judged that the vehicle optical cable is in normal use. After determining that the on-board optical cable has a fault, the fitted temperature curve and the actual temperature curve are compared in proportion, and the segmented node position of the external temperature detection module is mapped to the actual temperature curve. Based on this, the segmented interval where the fault occurs is determined and the distance from the fault point to the nearest segmented node is calculated.

2. The fault monitoring method of the vehicle-mounted optical cable according to claim 1, characterized in that: The segmentation standards for on-board optical cables include: The vehicle body components are grouped based on each other, and a segment node is set between two adjacent groups of vehicle body components, wherein the vehicle body components are independently detachable components; In each group of vehicle body components, a segment node is arranged at a bending position of each vehicle-mounted optical cable; In each group of vehicle body components, when the vehicle-mounted optical cable has no bend, a plurality of segment nodes are arranged with equidistant lengths.

3. The fault monitoring method of the vehicle-mounted optical cable according to claim 1, characterized in that: The steps of fitting the temperature curve of the vehicle optical cable exterior using multi-point temperature detection information are as follows: Assuming segment node positions x 1, x 2… x n Measured temperatures T1, T2…T n Construct a polynomial regression model: T ( x )= β 0+ β 1 x + β 2 x 2 + β 3 x 3 +…+ β k x k + ε ； in: T ( x ) is the temperature with respect to position x Function of β 0, β 1, β 2,… β k are the coefficients of the polynomial; ε is the error term, which represents the random error that cannot be explained by the model; Collect location points x i and the corresponding temperature measurement value T i , the location point x i Convert to polynomial features and get the feature matrix X: ； Solving for the coefficients of a polynomial using the least squares method β 0, β 1, β 2,… β k To minimize the residual sum of squares, the solution of the least squares method can be obtained by the following formula: ； Where: X is the feature matrix, each row contains x i The power of ; T is a column vector of temperature measurements; are estimates of the polynomial coefficients.

4. The fault monitoring method of the vehicle-mounted optical cable according to claim 1, characterized in that: Infrared temperature measurement technology is used to perform contactless temperature detection at each segment node outside the on-board optical cable.

5. The fault monitoring method of the vehicle-mounted optical cable according to claim 4, characterized in that: Under different ambient temperatures, the temperature of each segmented node outside the vehicle-mounted optical cable is detected, a model of the impact of ambient temperature on the temperature of the optical cable is established, and the formed fitting temperature curve is dynamically corrected in combination with the ambient temperature.

6. The fault monitoring method of the vehicle-mounted optical cable according to claim 1, characterized in that: Distributed optical fiber temperature measurement technology is used in vehicle-mounted optical cables to obtain the temperature distribution along the optical fiber path by measuring the changes in the intensity of the optical signal of Rayleigh scattering or Raman scattering in the optical fiber.

7. The fault monitoring method of the vehicle-mounted optical cable according to claim 1, characterized in that: When comparing the changing trends of the fitted temperature curve and the actual temperature curve in real time, a threshold is set to determine whether the temperature difference between the fitted temperature curve and the actual temperature curve exceeds the normal range, wherein: the threshold is determined by the temperature changing trend when the actual simulated vehicle optical cable fails.

8. The fault monitoring method of a vehicle-mounted optical cable according to claim 1, characterized in that: When comparing the fitted temperature curve and the actual temperature curve in proportion, a visualization method is used to draw the fitted temperature curve and the actual temperature curve on the same scale.

9. The fault monitoring method of the vehicle-mounted optical cable according to claim 1, characterized in that: The following steps are also included: When it is determined that the on-board optical cable fails, the time and location of the failure are recorded, and an alarm signal is sent to the central control system; Establish a fault database and collect data on each fault that occurs.

10. A vehicle-mounted optical cable fault monitoring system, used to implement the vehicle-mounted optical cable fault monitoring method according to any one of claims 1 to 9, characterized in that: include: A segmentation module is used to divide the vehicle-mounted optical cable into multiple segment intervals according to the layout position in the vehicle body, and define segment nodes between each segment; The external temperature detection module is arranged at each segment node, and is used to detect the temperature outside the vehicle optical cable and collect multi-point temperature data to form a fitting temperature curve; The internal temperature detection module is integrated inside the vehicle-mounted optical cable and uses optical fiber temperature measurement technology to detect the optical fiber temperature and generate an actual temperature curve; The monitoring and analysis module is used to compare the changing trends of the fitted temperature curve and the actual temperature curve in real time, and identify the potential fault location by analyzing the difference between the two. When it is found that the heating rate of the actual temperature curve at a certain location exceeds the heating rate of the fitted temperature curve, it is judged that the vehicle optical cable has a fault at that location. Otherwise, it is judged that the vehicle optical cable is in normal use. After confirming the fault, the fault location module can map the segmented nodes of the external temperature detection module to the actual temperature curve according to the proportional relationship between the fitted temperature curve and the actual temperature curve, thereby determining the specific segmented interval where the fault occurs and its precise distance from the nearest segmented node.

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