Pre-derailment detection method and system

Abstract

The invention discloses a pre-derailment detection method, which comprises the following steps of: A1, receiving information of an included angle between a bearing and the ground sensed by a six-axis sensor and an acceleration value in a vertical direction; a2, when the included angle between the bearing and the ground is larger than a preset threshold value, whether the acceleration in the vertical direction is larger than the preset threshold value or not is judged, and if yes, a derailment alarm signal is output. The invention further discloses a pre-derailment detection system which comprises the six-axis sensor, the six-axis sensor is installed at the axial end of the bogie and the dead center position of the bearing and used for collecting the angle and acceleration information of the bearing; the monitoring host is arranged in a compartment shielding cabinet or a seat cabinet and is used for receiving the information of the included angle between the bearing and the ground sensed by the six-axis sensor and sent by the preprocessor and the acceleration value in the vertical direction; and the preprocessor is mounted at the bottom of the vehicle body and is used for collecting signals acquired by the six-axis sensor. Compared with the prior art, pre-judgment diagnosis before train derailment can be achieved.

Description

Technical Field

[0001] The present invention relates to the field of rail transit technology, and in particular to a pre-derailment detection method and system. Background Art

[0002] With the improvement of the safety of domestic rail transit vehicles, various operating companies have paid more and more attention to safety accidents, among which train derailment is a major safety accident. The derailment detection system currently installed in China can only realize emergency braking after the train derails. Emergency braking after the train derails can only reduce losses. In addition, the time interval from derailment to emergency braking of the current derailment detection system is generally about 2s. This time interval cannot guarantee that there will be no casualties. Therefore, it is necessary to conduct pre-derailment diagnosis and apply emergency braking.

[0003] However, the existing derailment detection system can only apply emergency braking after the derailment alarm, and the interval period is generally about 2 seconds.

[0004] There are currently two derailment detection solutions. One is a passive derailment detection device, which is installed on the inner side of the vehicle wheelset, similar to a caliper device. When the wheelset derails and falls off the track, the displacement of the wheelset will trigger the caliper device to apply emergency braking, and at the same time send a signal to the leading and trailing vehicles and control the TCMS to apply emergency braking to the entire vehicle. This solution is expensive, and emergency braking can only be implemented after the vehicle derails. If the vehicle speed is too fast, it may cause significant losses.

[0005] Another solution is to integrate it into the running gear monitoring system, collect the impact signal of the vehicle wheels in real time through the composite sensor installed at the axle end, and make a real-time judgment on the detected vibration signal through the set threshold. If it exceeds the threshold and meets the derailment characteristics, the derailment signal is output to the running gear monitoring host, and the running gear monitoring host sends the derailment signal to EB (emergency braking system) and ATC (automatic driving system) in the form of a dry node. Since this solution is integrated into the running gear monitoring system, the overall cost is low, but there is a certain probability of false triggering (such as signal interference, or sensor failure, etc.) in the function realization, and the triggering braking time is long, which will also cause greater losses.

[0006] In view of this, a pre-derailment detection method and system are proposed. Summary of the invention

[0007] The object of the present invention is to provide a pre-derailment method and system, which can realize pre-diagnosis before train derailment.

[0008] The above technical objectives of the present invention are achieved through the following technical solutions:

[0009] A pre-derailment detection method comprises the steps of:

[0010] A1, receiving the angle information between the bearing and the ground and the acceleration value in the vertical direction sensed by the six-axis sensor;

[0011] A2. When the angle between the bearing and the ground is greater than the preset threshold, determine whether the acceleration in the vertical direction is greater than the preset threshold. If so, output a derailment alarm signal.

[0012] In a preferred embodiment, A2 specifically includes: when the angle between the bearing and the ground is greater than a preset threshold, determine whether the acceleration in the vertical direction is greater than the preset threshold, if greater, define this time as time A, define the acceleration in the vertical direction at time A as data A, and use time A as the starting point to search for the sudden increase moment of acceleration forward along time, the time corresponding to the maximum acceleration in the time period in which the acceleration in the vertical direction is continuously greater than the preset threshold is the sudden increase moment, and this acceleration is defined as data B, and when (data B-data A) / (time A-sudden increase moment) is less than the preset value, output a derailment alarm signal.

[0013] A pre-derailment detection system, comprising:

[0014] The six-axis sensor is installed at the axial end of the bogie, at the exact center of the bearing, to collect the angle and acceleration information of the bearing;

[0015] The monitoring host is installed in the carriage shielding cabinet or the seat cabinet, and is used to receive the bearing-ground angle information and the vertical acceleration value sensed by the six-axis sensor sent by the pre-processor; when the bearing-ground angle is greater than the preset threshold, it is determined whether the vertical acceleration is greater than the preset threshold, and if so, a derailment alarm signal is output;

[0016] The pre-processor is installed at the bottom of the vehicle body and is used to collect the signals collected by the six-axis sensor;

[0017] The six-axis sensor is communicatively connected to the preprocessor, and the preprocessor is communicatively connected to the monitoring host.

[0018] In a preferred embodiment, the monitoring host is installed in a carriage shielding cabinet or a seat cabinet, and is used to receive the bearing-ground angle information and the vertical acceleration value sent by the preprocessor via the six-axis sensor; when the bearing-ground angle is greater than a preset threshold, it is determined whether the vertical acceleration is greater than the preset threshold. If it is greater, this time is defined as time A, and the vertical acceleration at time A is defined as data A. The time A is used as the starting point to search for the sudden increase moment of acceleration forward along time. The time period in which the vertical acceleration is continuously greater than the preset threshold is the sudden increase moment. This acceleration is defined as data B. When (data B-data A) / (time A-sudden increase moment) is less than the preset value, a derailment alarm signal is output.

[0019] In a preferred embodiment, the six-axis sensor and the preprocessor are transmitted via CAN bus or RS485 digital signals, and the preprocessor and the monitoring host are transmitted via Ethernet.

[0020] In a preferred embodiment, a shock-absorbing box is arranged on the signal transmission line of the six-axis sensor, and the shock-absorbing box includes a box body, a filling material and a plurality of line clips. The box body is provided with a plurality of fixing plates, and the fixing plates are provided with a plurality of fixing through holes. The box body is fixed to the axle box by passing bolts through the fixing through holes. An intermediate mounting block is arranged in the box body, and a plurality of the line clips fix the signal transmission line to the intermediate mounting block. The signal transmission line located between the two line clips is bent, and the bending angle is not less than 180°. The filling material is filled in the box body.

[0021] In a preferred embodiment, the shock absorbing box is 3-5 cm away from the six-axis sensor.

[0022] In a preferred embodiment, the filling material is polyurethane foam or polystyrene foam.

[0023] In a preferred embodiment, the box body is penetrated by the signal transmission line, and a flexible portion is provided at a position of the box body where the signal transmission line penetrates, and the flexible portion is made of rubber material.

[0024] In a preferred embodiment, two independent processors MCU1 and MCU2 are provided in the preprocessor.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. Solve the problem of large delay in derailment alarm. Since the current derailment detection system outputs an alarm signal within 2 seconds after detecting a train derailment, it can only play a role in reducing losses and is of little significance. The present invention can achieve early warning before derailment and instant alarm of train derailment, greatly improving the safety of vehicle operation;

[0027] 2. By detecting the bearing posture, the operating status of the train can be determined more accurately. Compared with impact detection, the judgment logic is simpler and the accuracy is higher. Compared with the passive derailment detection device, the vehicle layout is simpler, the cost is lower, and the derailment diagnosis output is more timely.

[0028] 3. The derailment detection system can be integrated into the bogie comprehensive monitoring system as an auxiliary function, which can reduce system costs and increase product added value. At the same time, the three-axis vibration acceleration and three-axis angular velocity data collected by the six-axis sensor can be used for comprehensive analysis of vehicle dynamics and provide data support for vehicle component life prediction;

[0029] 4. Pre-derailment detection can realize all-round monitoring of vehicle status through the collected data, so as to adjust the derailment warning angle threshold in real time. The system architecture is simple, the diagnosis is accurate, and the safety is greatly improved.

[0030] 5. The three-axis angle data collected by the six-axis sensor can be used to develop other vehicle control system functions. At the same time, the angle data can better grasp the real-time operating status of the vehicle, which is of great help to vehicle positioning and vehicle status control. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The present invention relates to a flow chart of a pre-derailment detection method.

[0032] Figure 2 The invention relates to a pre-derailment detection system topology diagram.

[0033] Figure 3 It refers to the contact between wheelset and track in straight running state.

[0034] Figure 4 It is the wheel-to-rail contact condition when the lift threshold h is reached in the straight-line running state.

[0035] Figure 5 It refers to the contact between wheelset and track when running on a curve.

[0036] Figure 6 It refers to the contact condition between wheelset and track when the high rail is at the lifting threshold h in the curved running state.

[0037] Figure 7 It is the wheel-rail contact condition when the lower rail is at the lift threshold h in the curved running state.

[0038] Figure 8 The invention relates to a structural schematic diagram of a shock absorbing box used in a pre-derailment detection system.

[0039] Fig. 9 The present invention relates to a schematic diagram of a signal transmission line in a shock-absorbing box used in a pre-derailment detection system.

[0040] In the figure

[0041] Signal transmission line 1; box body 2; filling material 3; line card 4; fixing plate 5; fixing through hole 6; middle mounting block 7; flexible part 8. DETAILED DESCRIPTION

[0042] The present invention is further described in detail below in conjunction with the accompanying drawings.

[0043] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

[0044] Embodiment 1:

[0045] At present, the forms of wheel derailment can be roughly divided into five situations: climbing rail derailment, sliding rail derailment, jumping rail derailment, wheel suspension derailment, and track damage derailment. Among them, climbing rail derailment and sliding rail derailment are both caused by excessive axial angle deflection, causing the wheel flange to slide to the top of the rail and derail. In this case, one side of the wheelset will be higher than the other side of the wheelset. The lateral acceleration value can be used to infer whether the vehicle is in a cornering state at this moment, and then the bearing and the ground angle threshold are synchronized to trigger the derailment warning; jumping rail derailment, wheel suspension derailment, and track damage derailment all occur when one side of the wheelset bounces up or falls off the rail. Similarly, the lateral acceleration value can be used to infer whether the vehicle is in a cornering state at this moment, and then the bearing and the ground angle threshold are synchronized to trigger the derailment warning. After the derailment warning is triggered, if the vehicle derails, the wheel will be subjected to a severe impact signal in the vertical direction. By collecting the vertical acceleration value, after the derailment warning is triggered, the vertical direction large impact threshold is met at the same time, and the derailment alarm signal is directly output. By adding the derailment warning function, the accuracy of the derailment alarm will be greatly improved. Based on this, the present embodiment is produced.

[0046] like Figure 1 As shown, a pre-derailment detection method comprises the steps of:

[0047] A1, receiving the angle information between the bearing and the ground and the acceleration value in the vertical direction sensed by the six-axis sensor;

[0048] A2. When the angle between the bearing and the ground is greater than the preset threshold, determine whether the acceleration in the vertical direction is greater than the preset threshold. If so, output a derailment alarm signal.

[0049] Through the above method, it is possible to achieve predictive diagnosis of train derailment before derailment occurs, and send the signal to the train control system, so that predictive processing can be done in advance to avoid vehicle derailment. At the same time, from a cost perspective, it can be integrated into other systems to achieve the availability of the solution.

[0050] Further, A2 specifically includes: when the angle between the bearing and the ground is greater than a preset threshold, determine whether the acceleration in the vertical direction is greater than the preset threshold, if greater, define this time as time A, define the acceleration in the vertical direction at time A as data A, and use time A as the starting point to search for the sudden increase moment of acceleration forward along time, within the time period when the acceleration in the vertical direction is continuously greater than the preset threshold, the time corresponding to the maximum acceleration is the sudden increase moment, and this acceleration is defined as data B, and when (data B-data A) / (time A-sudden increase moment) is less than the preset value, output a derailment alarm signal.

[0051] Through the above steps, the accuracy of the alarm signal can be effectively improved. The main principle is that if when a severe impact signal occurs, when the angle between the bearing and the ground is greater than the preset threshold, the acceleration in the vertical direction changes greatly, so that the derailment can be controlled, then no alarm signal is issued. If the acceleration changes little, it means that the future derailment is uncontrollable, so an alarm signal is issued, thereby deleting some signals that will not eventually cause derailment, avoiding false triggering of alarms.

[0052] Embodiment 2:

[0053] like Figures 2 to 9 As shown, a pre-derailment detection system comprises:

[0054] The six-axis sensor is installed at the axial end of the bogie, at the exact center of the bearing, to collect the angle and acceleration information of the bearing. One sensor is installed on each shaft. To improve the detection accuracy, the bearings are installed diagonally on the bogie. The six-axis sensor includes an XYZ three-axis accelerometer and an XYZ three-axis gyroscope sensor. The sensor is powered by DC12V, and power isolation is done inside the sensor to ensure that the output signal does not interfere with the input signal.

[0055] The monitoring host is installed in the carriage shielding cabinet or the seat cabinet, and is used to receive the bearing and ground angle information and the vertical acceleration value sensed by the six-axis sensor sent by the pre-processor; when the bearing and ground angle is greater than the preset threshold, it is judged whether the vertical acceleration is greater than the preset threshold. If it is greater, a derailment alarm signal is output. When the alarm signal is issued, the monitoring host outputs a derailment dry node signal to the train control system, and the train control system applies emergency braking to the vehicle to reduce the loss caused by derailment.

[0056] The preprocessor is installed at the bottom of the car body and is used to collect the signals collected by the six-axis sensor. The preprocessor is powered by DC24V. One preprocessor is responsible for collecting the signals collected by four six-axis sensors in one car.

[0057] The six-axis sensor is communicatively connected to the preprocessor, and the preprocessor is communicatively connected to the monitoring host.

[0058] Through a pre-derailment detection system of the present embodiment, it is possible to implement pre-diagnosis before a train derails, and send the signal to the train control system, so that pre-diagnosis processing can be performed in advance to avoid vehicle derailment. At the same time, from a cost perspective, it can be integrated into other systems to achieve the availability of the solution.

[0059] Furthermore, the monitoring host is installed in the carriage shielding cabinet or the seat cabinet, and is used to receive the bearing and ground angle information and the vertical acceleration value sent by the preprocessor via the six-axis sensor; when the bearing and ground angle is greater than the preset threshold, it is determined whether the vertical acceleration is greater than the preset threshold. If it is greater, this time is defined as time A, and the vertical acceleration at time A is defined as data A. The time A is used as the starting point to search for the sudden increase moment of acceleration forward along the time. The time period in which the vertical acceleration is continuously greater than the preset threshold is the sudden increase moment. This acceleration is defined as data B. When (data B-data A) / (time A-sudden increase moment) is less than the preset value, a derailment alarm signal is output.

[0060] In this embodiment, the axial acceleration signal collected by the six-axis sensor 1 can be filtered through a low-pass filter of 0 to 5 Hz to obtain the current bearing lateral acceleration a. According to the relationship between the turning radius and the height difference between the inner and outer rails hx = 11.8a, the height difference between the inner and outer rails hx can be calculated. According to the parameters such as the bearing length and the track width, the angle αx° between the track and the horizontal plane can be obtained through the trigonometric function. According to the preset wheel lift threshold h of the research conclusion, the bearing angle threshold ±α1° can be calculated. For example, under the working conditions of the inner and outer rail height difference hx = 120mm, the track width is 1435mm, and the wheelbase is 2300mm, by calculation, in the case of a height difference of 120mm, the angle between the bearing and the horizontal plane is about ±3°, and the current pre-derailment threshold interval is ±(α1+3)°. This threshold changes all the time according to the vehicle operation status and line conditions.

[0061] The six-axis sensor and the preprocessor are transmitted via CAN bus or RS485 digital signals, which can ensure that the long-distance transmission signal is not distorted. The preprocessor and the monitoring host are transmitted via Ethernet. The collected data are aggregated and transmitted to the monitoring host via Ethernet. The monitoring host is responsible for diagnosing and storing the data.

[0062] Furthermore, the six-axis sensor can use analog signal transmission, and the ADC is placed in the pre-processor, which improves the sampling rate of the data at each measuring point, improves the accuracy of diagnosis, and shortens the early warning and alarm cycle.

[0063] A shock-absorbing box is arranged on the signal transmission line 1 of the six-axis sensor, and the shock-absorbing box includes a box body 2, a filling material 3 and a plurality of line clips 4. A plurality of fixing plates 5 are arranged on the box body 2, and a plurality of fixing through holes 6 are arranged on the fixing plates 5. The box body 2 is fixed in the axle box by passing bolts through the fixing through holes 6. An intermediate mounting block 7 is arranged in the box body 2, and a plurality of the line clips 4 fix the signal transmission line 1 on the intermediate mounting block 7. The signal transmission line 1 located between the two line clips 4 is bent, and the bending angle is not less than 180°.

[0064] The shock-absorbing box effectively reduces the impact of the vibration of the signal transmission line 1 on the six-axis sensor through its structural design, and effectively improves the accuracy of the six-axis sensor sensing signal. This is crucial for devices or systems that rely on six-axis sensor data for precise operation, ensuring the stable operation and precise control of related equipment.

[0065] The box body 2 of the shock-absorbing box is fixed to the axle box by bolts through the fixing through holes 6 on the fixing plate 5, which ensures the stability of its installation and provides a solid foundation for subsequent shock-absorbing work. The middle mounting block 7 in the box body 2 cooperates with multiple line cards 4 to fix the signal transmission line 1, and the signal transmission line 1 is bent between the two line cards 4, with a bending angle of not less than 180°. This bending method effectively interrupts the transmission of vibration, making it difficult for external vibration to be transmitted to the six-axis sensor through the signal transmission line 1.

[0066] The shock absorbing box is 3-5cm away from the six-axis sensor. From the perspective of shock absorption effect, the closer distance can ensure that the vibration on the signal transmission line 1 is suppressed to the maximum extent by the shock absorbing box before it is transmitted to the sensor, effectively reducing the signal interference and error caused by the vibration, and ensuring that the six-axis sensor stably and accurately senses the signal. In terms of installation, such a distance setting provides sufficient installation space for the six-axis sensor and the shock absorbing box. Neither will the two interfere with each other during installation due to the close distance, affecting the assembly of the equipment, nor will the shock absorption effect be weakened due to the long distance.

[0067] The filling material 3 is polyurethane foam or polystyrene foam, which has good cushioning and flame retardant effects, and is conducive to ensuring safety and achieving good cushioning and shock absorbing effects.

[0068] In order to further improve the buffering and shock absorbing effect, the signal transmission line 1 passes through the box body 2, and a flexible portion 8 is provided at the position where the signal transmission line 1 passes through the box body 2, and the flexible portion 8 is made of rubber material.

[0069] The preprocessor is provided with two independent processors MCU1 and MCU2, which are mutually redundant. MCU1 is used for processing in a normal state, and MCU2 automatically takes over when MCU1 fails. The collected data is aggregated and transmitted to the monitoring host 3 via Ethernet, and the monitoring host 3 is responsible for diagnosing and storing the data.

[0070] Furthermore, the vertical measurement range of the three-axis acceleration in the six-axis sensor can be expanded to 1000g. Due to the huge impact force when a vehicle derails, when the pre-derailment is triggered, setting the corresponding impact threshold based on the actual situation of the line will greatly improve the accuracy of the derailment alarm.

[0071] Furthermore, to improve the accuracy of diagnosis, six-axis sensors can be installed at both ends of the same shaft. The absolute value of the bearing transverse axis angle data collected by the six-axis sensors on the left and right sides is averaged to more accurately determine the inclination angle of the bearing. At the same time, two independent ADCs are set inside the preprocessor to control the six-axis sensors at both ends of the bearing to collect data. At the same time, two central processors MCU1 and MCU2 are connected in parallel inside the preprocessor to receive the six-axis data of the six-axis sensors collected by the two ADCs. When all the equipment is normal, MCU1 calculates the data and outputs the derailment diagnosis results. When MCU1 fails, MCU2 automatically takes over. If one of the sensors fails, it will not affect the overall system function.

[0072] Furthermore, the diagnostic algorithm can be placed in the preprocessor, the monitoring host is responsible for receiving and storing the collected data, the preprocessor diagnoses the derailment warning and derailment alarm signals and transmits them to the monitoring host through hard lines, the monitoring host collects the derailment warning and derailment alarm signals of all preprocessors, performs OR logic, and outputs the signals to the train TCMS (train control system), EB (emergency braking system) and ATC (automatic driving system),

[0073] Furthermore, the pre-processor or the diagnostic host can access the vehicle speed pulse signal and associate the set angle warning threshold with the vehicle speed, thereby further improving the accuracy of the derailment warning or derailment alarm.

[0074] Furthermore, the pre-derail detection system can be integrated into the running gear monitoring system, sharing the existing pre-processor and running gear monitoring host of the running gear monitoring system, and becoming an optional function of the running gear monitoring system, thereby improving the accuracy of derailment alarms, adding derailment warning functions, and further reducing costs.

[0075] Furthermore, the data collected by the six-axis sensor can be used to carry out functional expansion such as vehicle dynamics analysis, life prediction, and vehicle health status monitoring.

[0076] Alternatively, the six-axis sensor can be split into a three-axis vibration sensor and a three-axis gyroscope sensor, and the configuration can be increased or decreased according to different customer needs.

[0077] Alternatively, the six-axis sensor can be directly connected to the monitoring host, thereby deleting the configuration of the pre-processor and reducing the equipment components, but at the same time increasing the difficulty of wiring.

[0078] Alternatively, a temperature sensor can be added inside the six-axis sensor to detect the axle box temperature, replacing the axle box composite sensor in the existing running gear monitoring system. By changing the installation interface without adding any additional equipment, the derailment warning function and the data collection of the bearing angle status can be achieved.

[0079] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or terminal device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of further restrictions, the elements defined by the sentence "include..." or "comprise..." do not exclude the existence of other elements in the process, method, article or terminal device including the elements. In addition, in this article, "greater than", "less than", "exceed" and the like are understood to exclude the number itself; "above", "below", "within" and the like are understood to include the number itself.

[0080] The above description of the embodiments is to facilitate the understanding and use of the present invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to the embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

1. A pre-derailment detection method, characterized in that: Includes steps: A1, receiving the angle information between the bearing and the ground and the acceleration value in the vertical direction sensed by the six-axis sensor; A2. When the angle between the bearing and the ground is greater than the preset threshold, determine whether the acceleration in the vertical direction is greater than the preset threshold. If so, output a derailment alarm signal.

2. A pre-derailment detection method according to claim 1, characterized in that: The A2 specifically includes: when the angle between the bearing and the ground is greater than a preset threshold, determine whether the acceleration in the vertical direction is greater than the preset threshold, if greater, define this time as time A, define the acceleration in the vertical direction at time A as data A, and use time A as the starting point to search for the sudden increase moment of acceleration along time forward, and within the time period when the acceleration in the vertical direction is continuously greater than the preset threshold, the time corresponding to the maximum acceleration is the sudden increase moment, and this acceleration is defined as data B, and when (data B-data A) / (time A-sudden increase moment) is less than a preset value, output a derailment alarm signal.

3. A pre-derailment detection system, characterized in that: include: The six-axis sensor is installed at the axial end of the bogie, at the exact center of the bearing, to collect the angle and acceleration information of the bearing; The monitoring host is installed in the carriage shielding cabinet or the seat cabinet, and is used to receive the bearing-ground angle information and the vertical acceleration value sensed by the six-axis sensor sent by the pre-processor; when the bearing-ground angle is greater than the preset threshold, it is determined whether the vertical acceleration is greater than the preset threshold, and if so, a derailment alarm signal is output; The pre-processor is installed at the bottom of the vehicle body and is used to collect the signals collected by the six-axis sensor; The six-axis sensor is communicatively connected to the preprocessor, and the preprocessor is communicatively connected to the monitoring host.

4. A pre-derailment detection system according to claim 3, characterized in that: The monitoring host is installed in the carriage shielding cabinet or the seat cabinet, and is used to receive the bearing and ground angle information and the vertical acceleration value sent by the pre-processor via the six-axis sensor; when the bearing and ground angle is greater than the preset threshold, it is judged whether the vertical acceleration is greater than the preset threshold. If it is greater, this time is defined as time A, and the vertical acceleration at time A is defined as data A. The time A is used as the starting point to find the sudden increase moment of acceleration forward along the time. The time period in which the vertical acceleration is continuously greater than the preset threshold is the sudden increase moment. This acceleration is defined as data B. When (data B-data A) / (time A-sudden increase moment) is less than the preset value, a derailment alarm signal is output.

5. A pre-derailment detection system according to claim 3, characterized in that: The six-axis sensor and the preprocessor are transmitted via CAN bus or RS485 digital signals, and the preprocessor and the monitoring host are transmitted via Ethernet.

6. A pre-derailment detection system according to claim 3, characterized in that: A shock-absorbing box is arranged on the signal transmission line of the six-axis sensor, and the shock-absorbing box includes a box body, a filling material and a plurality of line clips. The box body is provided with a plurality of fixing plates, and the fixing plates are provided with a plurality of fixing through holes. The box body is fixed to the axle box by passing bolts through the fixing through holes. An intermediate mounting block is arranged in the box body, and a plurality of the line clips fix the signal transmission line to the intermediate mounting block. The signal transmission line between the two line clips is bent, and the bending angle is not less than 180°. The filling material is filled in the box body.

7. A pre-derailment detection system according to claim 6, characterized in that: The shock absorbing box is 3-5 cm away from the six-axis sensor.

8. A pre-derailment detection system according to claim 6, characterized in that: The filling material is polyurethane foam plastic or polystyrene foam plastic.

9. A pre-derailment detection system according to claim 6, characterized in that: The signal transmission line passes through the box body, and a flexible portion is provided at a position of the box body where the signal transmission line passes through, and the flexible portion is made of rubber material.

10. A pre-derailment detection system according to claim 3, characterized in that: Two independent processors MCU1 and MCU2 are arranged in the preprocessor.

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