Railway wagon overload and unbalanced load detection method and device

Abstract

The invention discloses a vehicle overload and unbalanced load detection method and device, and the method comprises the steps: S1, setting the length of a photosensitive surface of a position sensitive detector based on an uneven amplitude; s2, placing a laser transmitter and a position sensitive detector in a measurement interval on the track to form a laser offset; s3, based on the downward pressure borne by the rail and the temperature stress in the rail, measuring the laser offset when the rail wagon passes through any measurement interval; s4, the laser offset is converted into an electric signal, the waveform effective value of the electric signal is calculated, and the wheel weights of the left side and the right side are calculated based on the waveform effective value; and S5, calculating weight parameters of the railway wagon, and evaluating a wheel tread state and a wheel-rail acting force condition. According to the invention, the existing line is not damaged, the detection sensitivity degree is high, and the railway wagon can be detected without deceleration; meanwhile, the influence of uneven track height and internal temperature stress is considered, and the stability and effectiveness of detection are ensured.

Description

Technical Field

[0001] The invention relates to the technical field of laser measurement, and in particular to a method and a device for detecting overloading and unbalanced loading of railway freight cars. Background Art

[0002] Overloading and unbalanced loading of railway freight cars are the main factors causing operation accidents. Detection of overloading and unbalanced loading can effectively improve the safety of railway freight car operation.

[0003] In the existing technology, the overload detection of railway freight cars is often achieved by letting railway freight cars pass through the rails in the detection area, and then using weighing sensors to detect the deformation of the rails. However, the shortcomings of this method are also very obvious. Special sleepers must be used for the detection area, which requires digging its foundation for construction, and the construction period itself is relatively long. In addition, this detection method requires railway freight cars to pass through the detection area slowly, which causes certain interference to the driving speed. At the same time, it is impossible to eliminate the impact of the unevenness of the railway track and the internal temperature stress. Summary of the invention

[0004] In view of this, the present invention proposes a method for detecting overloading and unbalanced loading of railway freight cars, comprising:

[0005] S1: Based on the height irregularity amplitude between two adjacent sleepers, the photosensitive surface length of the position sensitive detector is set;

[0006] S2: placing the laser emitter and the position sensitive detector in the measuring section on the track, so that the laser emitted by the laser emitter forms a laser offset on the photosensitive surface,

[0007] There are multiple groups of measurement intervals, each group of measurement intervals includes left and right tracks, and the left and right tracks of each group of measurement intervals are provided with the laser emitter and position sensitive detector;

[0008] S3: Based on the downward pressure on the track and the internal temperature stress of the track, measuring the laser offset when the railway freight car passes through any of the measurement intervals;

[0009] S4: converting the laser offset into an electrical signal, calculating a waveform effective value of the electrical signal, and calculating the wheel weights on the left and right sides of the railway freight car when the railway freight car passes through any of the measurement intervals based on the waveform effective value;

[0010] S5: Calculate the weight parameter of the railway freight car based on the wheel weights on the left and right sides, and evaluate the wheel tread state and wheel-rail force conditions based on the weight parameter.

[0011] Further, in S1, based on the height unevenness amplitude H2 between two adjacent sleepers, the length of the photosensitive surface is set, and the calculation expression of H2 is: Wherein L1 is the total length of the track in the unevenness area, H1 is the maximum unevenness amplitude allowed in the unevenness area, and L2 is the distance between two adjacent sleepers.

[0012] Furthermore, in S2, in any of the measurement intervals, the laser emitter and the position sensitive detector on the left or right side thereof are located between two adjacent sleepers.

[0013] Furthermore, in S3, at temperature t, the elastic coefficient k and constant coefficient b of the track are solved based on the front weight F of the railway freight car and its laser offset Δx, and the solution formula is: F=kΔx+b. The weight of the remaining carriages is calculated based on this elastic coefficient k and constant coefficient b; when the temperature change exceeds the set threshold, the elastic coefficient k and constant coefficient b are recalculated.

[0014] Accordingly, the present invention also provides a railway freight car overload detection device, comprising:

[0015] A collection unit, including a rail-mounted device, wherein the rail-mounted device includes a laser emitter and a position sensitive detector, wherein the laser emitter and the position sensitive detector are clamped on the rail by a fixture and are located between two adjacent sleepers;

[0016] The laser emitted by the laser emitter generates a laser offset Δx on the photosensitive surface of the position sensitive detector based on F and σt, F is the downward pressure on the track, and σt is the internal temperature stress of the track at temperature t;

[0017] Wherein, the length of the photosensitive surface of the position sensitive detector is set based on the amplitude of the height irregularity between the two adjacent sleepers;

[0018] The control and analysis unit is used to receive and analyze the collected data of the position sensitive detector.

[0019] According to a preferred embodiment, the laser emitters and position sensitive detectors are arranged in several groups on the left and right tracks, and each group is arranged at a certain distance from each other;

[0020] Each group of the laser emitters and position sensitive detectors is arranged longitudinally or transversely, and the number of the groups of the laser emitters and position sensitive detectors arranged longitudinally is greater than that of the groups of the laser emitters and position sensitive detectors arranged transversely.

[0021] According to a preferred embodiment, the acquisition unit further includes a trackside installation device, and the trackside installation device includes:

[0022] Wheel sensors, used to detect the position status of railway freight cars;

[0023] A monitoring camera, used to film the inspection process of the railway freight car and archive it;

[0024] A control box is connected to the acquisition unit and the wheel sensor and is used to transmit data to the control and analysis unit.

[0025] According to a preferred implementation, the control and analysis unit includes an industrial computer, a server, a UPS, a PDU, a KVM, and a switch, which are integrated in an electric control cabinet.

[0026] Furthermore, the electric control cabinet is placed close to or far away from the rails, and the electric control cabinet communicates with the collection unit via optical fiber.

[0027] Furthermore, the position sensitive detector is composed of three layers of semiconductor materials of different types stacked on a planar silicon substrate, including:

[0028] A P-type layer located on the surface, wherein the photosensitive surface is located on the P-type layer;

[0029] The type I layer is located in the middle;

[0030] The N-type layer at the bottom;

[0031] The P-type layer, the I-type layer and the N-type layer form a measuring electric field. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a flow chart of a method for detecting overloading and unbalanced loading of railway freight cars in the present invention;

[0033] Figure 2 It is a schematic diagram of the longitudinal installation of the laser emitter and the position sensitive detector in the present invention;

[0034] Figure 3 It is a schematic diagram of the horizontal installation of the laser emitter and the position sensitive detector in the present invention;

[0035] Figure 4 It is a schematic diagram of the composition of a railway freight car overload and unbalanced load detection device in the present invention;

[0036] Figure 5 It is a schematic diagram of the internal electric field of the position sensitive detector in the present invention.

[0037] Explanation of the reference numerals: 1 - laser transmitter, 2 - position sensitive detector, 3 - sleeper. DETAILED DESCRIPTION

[0038] Overloading and unbalanced loading of railway freight cars are the main factors causing operation accidents. Detection of overloading and unbalanced loading can effectively improve the safety of railway freight car operation.

[0039] In the existing technology, the overload detection of railway freight cars is often achieved by letting railway freight cars pass through the rails in the detection area, and then using weighing sensors to detect the deformation of the rails. However, the shortcomings of this method are also very obvious. Special sleepers must be used for the detection area, which requires digging its foundation for construction, and the construction period itself is relatively long. In addition, this detection method requires railway freight cars to pass through the detection area slowly, which causes certain interference to the driving speed. At the same time, it is impossible to eliminate the impact of the unevenness of the railway track and the internal temperature stress.

[0040] In view of this, the present invention proposes a method and device for detecting overloading and unbalanced loading of railway freight cars. In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0041] like Figure 1 As shown, the present invention discloses a method for detecting overloading and unbalanced loading of railway freight cars, comprising:

[0042] S1: Based on the height irregularity amplitude H2 between two adjacent sleepers, the photosensitive surface length of the position sensitive detector is set;

[0043] S2: placing the laser emitter and the position sensitive detector in the measuring section on the track, so that the laser emitted by the laser emitter forms a laser offset Δx on the photosensitive surface,

[0044] There are multiple groups of measurement intervals, each group of measurement intervals includes left and right tracks, and the left and right tracks of each group of measurement intervals are provided with the laser emitter and position sensitive detector;

[0045] S3: Based on the downward pressure F exerted on the track and the internal temperature stress σt of the track, measuring the laser offset Δx when the railway freight car passes through any of the measurement intervals;

[0046] S4: converting the laser offset Δx into an electrical signal, calculating a waveform effective value of the electrical signal, and calculating the wheel weights on the left and right sides of the railway freight car when the railway freight car passes through any of the measurement intervals based on the waveform effective value;

[0047] S5: Calculate the weight parameter of the railway freight car based on the wheel weights on the left and right sides, and evaluate the wheel tread state and wheel-rail force conditions based on the weight parameter.

[0048] The photosensitive surface of the position sensitive detector refers to the area that can respond to and sense the incident laser energy. In this area, when the laser is irradiated, an electrical signal related to the laser position is generated, thereby realizing sensitive detection of the spot position.

[0049] Among them, since the distance between adjacent sleepers is relatively fixed, this can be used as a distance reference, and the laser transmitter and the position sensitive detector can be clamped between two adjacent sleepers on the track using a fixture.

[0050] In one embodiment, a four-axle eight-wheel truck is taken as an example to illustrate the detection and evaluation process:

[0051] When the first set of two front wheels begin to pass through the first measurement interval, the laser offsets on the left and right sides are measured and converted into electrical signals;

[0052] For the first left front wheel, WL1_P1=v*(HL1_P1), where WL1_P1 represents the weight of the first left front wheel on the left side of area P1, v is the wheel weight correction coefficient, and HL1_P1 is the effective value of the electrical signal corresponding to the laser offset Δx on the left side of area P1;

[0053] For the first right front wheel, WR1_P1=v*(HR1_P1), where WR1_P1 represents the weight of the first right front wheel on the right side of area P1, v is the wheel weight correction coefficient, and HR1_P1 is the effective value of the electrical signal corresponding to the laser offset Δx on the right side of area P1;

[0054] Repeat the above steps for n areas in sequence to obtain WL1_P2, WL1_P3...WL1_Pn, then the first left front wheel average wheel weight WL1 = (WL1_P1 + WL1_P2...WL1_Pn) / n can be calculated. Similarly, the first right front wheel average wheel weight WR1 can be calculated.

[0055] Repeat the above steps to calculate other average wheel weights WL2, WL3, WL4, WR2, WR3, and WR4.

[0056] Based on the above average wheel weight, weight parameters can be obtained, including:

[0057] The gross weight of the truck is:

[0058] W=WL1+WL2+WL3+WL4+WR1+WR2+WR3+WR4,

[0059] Weight difference between front and rear bogies of a freight car:

[0060] W=WL1+WL2+WR1+WR2-WL3-WL4-WR3-WR4,

[0061] Load eccentricity of front bogie of freight car:

[0062] RF=(WL1+WL2-WR1-WR2) / (WL1+WL2+WR1+WR2),

[0063] Eccentricity rate of rear bogie of freight car:

[0064] RB=(WL3+WL4-WR3-WR4) / (WL3+WL4+WR3+WR4),

[0065] Load eccentricity of the truck:

[0066] RT=(WL1+WL2+WL3+WL4-WR1-WR2-WR3-WR4) / (WL1+WL2+WL3+WL4+WR1+WR2+WR3+WR4),

[0067] Based on the above weight parameters, the wheel tread condition and wheel-rail force conditions are evaluated.

[0068] In the present invention, a laser emitter and a position sensitive detector are installed on the track on which a railway freight car passes by using a clamp, which is convenient to install and does not damage the rails and spring buckle system of the existing line; the laser emitter and the position sensitive detector are highly sensitive, and the railway freight car can be detected without slowing down; the elastic deformation of the rail is used as a direct detection quantity, and the calculation accuracy of the wheel-rail force is high, which can accurately reflect the overload and eccentricity state of the railway freight car; at the same time, the influence of the track height unevenness amplitude and the internal temperature stress is taken into consideration, thereby ensuring the stability and effectiveness of the detection.

[0069] According to a preferred embodiment, in S1, based on the height unevenness amplitude H2 between two adjacent sleepers, the length of the photosensitive surface is set, and the calculation expression of H2 is: Wherein L1 is the total length of the track in the unevenness area, H1 is the maximum unevenness amplitude allowed in the unevenness area, and L2 is the distance between two adjacent sleepers.

[0070] The ballasted track on which railway freight and passenger cars run, that is, the gravel ballast track, has complex geological conditions and poor ballast stability. Under the complex environment and long-term action of train loads, large dynamic stress will be generated on the roadbed surface, which is prone to excessive roadbed deformation and uneven roadbed settlement, affecting the track structure, changing the relative position of the sleepers and the mechanical properties of the track; the resulting uneven fluctuations are called track unevenness, among which the vertical unevenness is called height unevenness.

[0071] When the distance between two adjacent sleepers is L2 in a track with a length of L1, consider the extreme case: the maximum allowable height irregularity amplitude is H1. Since the height irregularity can be approximately regarded as uniformly distributed, the height irregularity amplitude H2 between two adjacent sleepers can be calculated as follows: Then, according to H2, the length of the photosensitive surface of the position sensitive detector is set to ensure that within the maximum allowable range, the deformation of the rail caused by the roadbed settlement is always within the measurable area of ​​the position sensitive detector.

[0072] Below is an example of calculating the amplitude of 16mm unevenness within 10m as specified in the "Rules for Repair of Conventional Railway Lines" (TG / GW102-2019): Assuming the sleeper spacing is 600mm, the 16mm unevenness within 10m is converted to the spacing between two adjacent sleepers to be approximately 0.95mm. Considering that the 0.95mm deformation is still within the elastic deformation of the rail, and the rail deformation caused by settlement will not change in the short term, the photosensitive surface length of the position sensitive detector is designed to be 3.5mm when designing the laser-position sensitive detector.

[0073] Furthermore, there are several groups of laser emitters and position sensitive detectors, and each group is arranged at a certain distance.

[0074] By setting up multiple sets of laser emitters and position-sensitive detectors, multi-point measurements can be performed on different locations of the truck passing through the detection section. This multi-point measurement method can more comprehensively capture the force exerted by the truck on the track at different locations, reducing the error that may be caused by a single measurement point; the setting of multiple sets of equipment also constitutes a redundant design. When a set of equipment fails or the measurement data is abnormal, the data of other sets of equipment can still be used as a reference to ensure the continuity and reliability of the entire detection system.

[0075] Each group is set at a certain distance apart. You can refer to the above and use the adjacent sleepers with relatively fixed distance as a benchmark to ensure the accuracy of the measurement results.

[0076] Specifically, considering the length of common railway freight cars and the distance between adjacent sleepers, 14 sets of laser emitters and position sensitive detectors may be selected, with 7 sets for each of the left and right tracks.

[0077] According to a preferred embodiment, in S3, at temperature t, the elastic coefficient k and constant coefficient b of the track are solved based on the head weight F of the railway freight car and its laser offset Δx, and the solution formula is:

[0078] F=kΔx+b, the weight of the remaining carriages is calculated based on the elastic coefficient k and the constant coefficient b; when the temperature change exceeds the set threshold, the elastic coefficient k and the constant coefficient b are recalculated.

[0079] The threshold value can be set according to actual conditions, and the setting standard is: this temperature change will obviously affect the elastic coefficient k and constant coefficient b of the track.

[0080] Due to the significant extension of the rail length, a particular track line, especially a seamless long track line, is characterized by a significant extension of the rail length. When the ambient temperature changes, the rail will tend to expand and contract due to the thermal expansion and contraction effect. However, due to the existence of external constraints, this expansion and contraction is limited, and significant axial thermal stress accumulates inside the rail. The change in this stress state will directly lead to the deviation of the elastic coefficient k and the constant coefficient b, which will have an adverse effect on the accuracy of the detection system.

[0081] Therefore, the starting point of the above implementation is that, since the detection time is short (about 15s), it can be considered that the temperature has not changed during the detection process, and the wheel-rail force and the offset measured by the laser still maintain a linear relationship. It’s just that the values ​​of the elastic coefficient k and the constant coefficient b are different under different temperature conditions. For railway freight cars, the weight of the locomotive head is relatively fixed. The wheel-rail force elastic coefficient k and the constant coefficient b can be calculated based on the known weight and the laser offset, and then the wheel weight of the remaining cars is calculated based on this. And every time a car passes, it is dynamically calibrated using the known locomotive head weight to solve the elastic coefficient k and the constant coefficient b at the current temperature to obtain the correct wheel-rail force measurement value.

[0082] Correspondingly, such as Figure 2 As shown, the present invention also provides a railway freight car overload detection device, comprising:

[0083] The collection unit includes a rail-mounted device, wherein the rail-mounted device includes a laser emitter and a position sensitive detector, wherein the laser emitter and the position sensitive detector are clamped on the rail by a fixture. Specifically, multiple groups of laser emitters and position sensitive detectors are symmetrically arranged on the left and right rails, and there are two setting methods: longitudinal setting and transverse setting. As a preferred setting method, 14 groups of laser emitters and position sensitive detectors can be selected, wherein 7 groups are arranged on the left and right rails, and the 7 groups include 6 groups arranged longitudinally and one group arranged transversely.

[0084] The laser emitted by the laser emitter generates a laser offset Δx on the photosensitive surface of the position sensitive detector based on F and σt, F is the downward pressure on the track, and σt is the internal temperature stress of the track at temperature t;

[0085] Wherein, the length of the photosensitive surface of the position sensitive detector is set based on the amplitude of the height irregularity between the two adjacent sleepers;

[0086] The control and analysis unit is used to receive and analyze the collected data of the position sensitive detector. The control and analysis unit includes an industrial computer, a server, a UPS, a PDU, a KVM, and a switch, which are integrated in an electric control cabinet.

[0087] Further, such as Figure 3 and Figure 4As shown, the laser emitters and position sensitive detectors are arranged longitudinally and transversely, and the number of the laser emitters and position sensitive detectors arranged longitudinally is greater than that of the laser emitters and position sensitive detectors arranged transversely.

[0088] In the above, the longitudinal setting refers to that the laser emitter and the position sensitive detector are relatively set in the vertical direction, and the transverse setting refers to that the laser emitter and the position sensitive detector are relatively set in the vertical and horizontal directions. Both settings can improve the accuracy of the detection results.

[0089] In the above, the number of the laser emitters and position sensitive detectors arranged longitudinally is greater than the number of the laser emitters and position sensitive detectors arranged transversely.

[0090] Furthermore, the acquisition unit further includes a trackside installation device, and the trackside installation device includes:

[0091] Wheel sensors are used to detect the position status of railway freight cars;

[0092] A monitoring camera, used to film the inspection process of the railway freight car and archive it;

[0093] A control box is connected to the acquisition unit and the wheel sensor and is used to transmit data to the control and analysis unit.

[0094] The above-mentioned trackside installation equipment is specifically installed within a certain range from the track so as not to affect the operation of railway freight cars and to ensure that it is in good working condition.

[0095] Furthermore, the electric control cabinet is placed close to or far away from the rails, and the electric control cabinet communicates with the collection unit via optical fiber.

[0096] The electric control cabinet and the acquisition unit communicate via optical fiber, so the site selection can be flexibly selected according to actual needs.

[0097] Furthermore, the position sensitive detector is composed of three layers of semiconductor materials of different types stacked on a planar silicon substrate, including:

[0098] The P-type layer located on the surface, the photosensitive surface is located in the P-type layer, and the P-type layer refers to the area where holes are the majority in the material through doping such as boron. The role of the P-type layer here is the main working area of ​​the photoelectric effect. When the laser is irradiated, the photon energy is absorbed by the silicon atoms in the P-type layer, causing electrons to be excited and form electron-hole pairs. These electrons and holes will separate and move under the action of the electric field, thereby generating electrical signals;

[0099] The I-type layer in the middle is a pure silicon layer without doping. Its main function is to serve as a transmission channel for electrons and holes, while providing a high-resistance area so that electrons and holes can be more effectively separated and move to both ends under the action of the electric field;

[0100] The N-type layer at the bottom is opposite to the P-type layer. The N-type layer is a region where electrons are the majority in the material through doping (such as phosphorus). A PN junction is formed between the N-type layer and the P-type layer, which is the key structure for generating an electric field. When an external voltage (usually a reverse bias voltage) is applied to the PN junction, a strong electric field is generated in the junction area. This electric field causes the electrons generated in the P-type layer to move to the N-type layer, while the holes move to the P-type layer, thereby forming a current. Since the position of the incident light spot affects the separation position of the electrons and holes, the position of the light spot can be determined by measuring the magnitude and direction of the current.

[0101] The holes reaching the P layer are divided into two parts: one part flows along the surface resistor R1 to the 1 end to form the photocurrent I1, and the other part flows along the surface resistor R2 to the 2 end to form the photocurrent I2. This is the signal conditioning process.

[0102] Furthermore, the internal resistance in the measurement circuit is RN, the external resistance is RL, the length L of the internal resistance is the length L of the photosensitive surface, the group value of the internal resistance RN is directly proportional to the length, and the laser offset Δx is the distance from the laser incident point to the midpoint of the photosensitive surface, satisfying the relationship Δx=f(RN, RL, V1, V2), where V1 and V2 are the voltages across the internal resistance RN.

[0103] Specifically, Figure 5 As shown, R1+R2=RN is the internal resistance of the position sensitive detector, which is a fixed value; the external resistance RL is known; the voltages across the two load resistors R1 and R2 of the position sensitive detector are V1 and V2 respectively, which can be obtained through the acquisition card and can be regarded as known conditions. Then I0=I1+I2 is constant,

[0104] Assuming that the midpoint of the position sensitive detector is the origin, the total length of the photosensitive surface of the position sensitive detector is L, the group value of the internal resistance RN is directly proportional to the length, so R1 and R2 satisfy the following relationship:

[0105] get According to the voltage relationship:

[0106] That is, we can finally get:

[0107]

[0108] Based on the above formula, the following conclusions can be drawn: the position information is only related to the laser incident point and has nothing to do with the light intensity; the resistance value of the resistor layer of the position sensitive detector sensor will affect the signal size of the two P ends.

[0109] The above is a detailed introduction to a wireless level ruler measurement auxiliary device and system provided by an embodiment of the present invention. The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, the present invention can also be improved and modified in a number of ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0110] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0111] The steps of the method or algorithm described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, a software module executed by a processor, or a combination of the two. The software module may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

Claims

1. A method for detecting overloading and unbalanced loading of railway freight cars, characterized in that: include: S1: Based on the height irregularity amplitude between two adjacent sleepers, the photosensitive surface length of the position sensitive detector is set; S2: placing the laser emitter and the position sensitive detector in the measuring section on the track, so that the laser emitted by the laser emitter forms a laser offset on the photosensitive surface, There are multiple groups of measurement intervals, each group of measurement intervals includes left and right tracks, and the left and right tracks of each group of measurement intervals are provided with the laser emitter and position sensitive detector; S3: Based on the downward pressure on the track and the internal temperature stress of the track, measuring the laser offset when the railway freight car passes through any of the measurement intervals; S4: converting the laser offset into an electrical signal, calculating a waveform effective value of the electrical signal, and calculating the wheel weights on the left and right sides of the railway freight car when the railway freight car passes through any of the measurement intervals based on the waveform effective value; S5: Calculate the weight parameter of the railway freight car based on the wheel weights on the left and right sides, and evaluate the wheel tread state and wheel-rail force conditions based on the weight parameter.

2. The method for detecting overloading and unbalanced loading of railway freight cars according to claim 1, characterized in that: In S1, based on the height unevenness amplitude H2 between two adjacent sleepers, the length of the photosensitive surface is set, and the calculation expression of H2 is: Wherein L1 is the total length of the track in the unevenness area, H1 is the maximum unevenness amplitude allowed in the unevenness area, and L2 is the distance between two adjacent sleepers.

3. The method for detecting overloading and unbalanced loading of railway freight cars according to claim 1, characterized in that: In S2, within any of the measuring intervals, the laser emitter and the position sensitive detector on the left or right side thereof are located between two adjacent sleepers.

4. The method for detecting overloading and unbalanced loading of railway freight cars according to claim 1, characterized in that: In S3, at temperature t, the elastic coefficient k and constant coefficient b of the track are solved based on the front weight F of the railway freight car and its laser offset Δx, and the solution formula is: F=kΔx+b. The weight of the remaining carriages is calculated based on this elastic coefficient k and constant coefficient b; when the temperature change exceeds the set threshold, the elastic coefficient k and constant coefficient b are recalculated.

5. A railway freight car overload detection device, characterized in that: include: A collection unit, including a rail-mounted device, wherein the rail-mounted device includes a laser emitter and a position sensitive detector, wherein the laser emitter and the position sensitive detector are clamped on the rail by a fixture and are located between two adjacent sleepers; The laser emitted by the laser emitter generates a laser offset Δx on the photosensitive surface of the position sensitive detector based on F and σt, F is the downward pressure on the track, and σt is the internal temperature stress of the track at temperature t; Wherein, the length of the photosensitive surface of the position sensitive detector is set based on the amplitude of the height irregularity between the two adjacent sleepers; The control and analysis unit is used to receive and analyze the collected data of the position sensitive detector.

6. The railway freight car overload detection device according to claim 5, characterized in that: There are several groups of laser emitters and position sensitive detectors, which are arranged on the left and right tracks, and each group is arranged at a certain distance. Each group of the laser emitters and position sensitive detectors is arranged longitudinally or transversely, and the number of the groups of the laser emitters and position sensitive detectors arranged longitudinally is greater than that of the groups of the laser emitters and position sensitive detectors arranged transversely.

7. The railway freight car overload detection device according to claim 5, characterized in that: The acquisition unit further includes a trackside installation device, and the trackside installation device includes: Wheel sensors are used to detect the position status of railway freight cars; A monitoring camera, used to film the inspection process of the railway freight car and archive it; A control box is connected to the acquisition unit and the wheel sensor and is used to transmit data to the control and analysis unit.

8. The railway freight car overload detection device according to claim 5, characterized in that: The control and analysis unit includes an industrial computer, a server, a UPS, a PDU, a KVM, and a switch, which are integrated in an electric control cabinet.

9. The railway freight car overload detection device according to claim 8, characterized in that: The electric control cabinet is placed close to or far away from the rails, and the electric control cabinet communicates with the collection unit via optical fiber.

10. The railway freight car overload and unbalanced load detection device according to claim 5, characterized in that: The position sensitive detector is composed of three layers of different types of semiconductor materials stacked on a planar silicon substrate, including: A P-type layer located on the surface, wherein the photosensitive surface is located on the P-type layer; The type I layer is located in the middle; The N-type layer at the bottom; The P-type layer, the I-type layer and the N-type layer form a measuring electric field.

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