Online monitoring device and method for the condition of circular link chain in mining scraper conveyors

Abstract

This invention discloses an online monitoring device and method for the condition of a circular link chain in a mining scraper conveyor, belonging to the field of online monitoring technology for mining scraper conveyors. The device includes a support frame, an X-ray detector, an X-ray emitter, a light source base, and a rotary encoder. The support frame is fixed to the tail of the scraper conveyor and supports the various components of the monitoring device. An X-ray detector is positioned above the circular link chain and is fitted to the lower surface of the support frame. An X-ray emitter is positioned opposite the X-ray detector below the middle plate at the tail, and is fixedly mounted via the light source base. The X-ray emitter emits X-rays upwards. A rotary encoder is installed on the sprocket shaft, which detects changes in the sprocket shaft's rotation angle in real time. This invention uses X-ray scanning to obtain information about damage and cracks in the circular link chain, solving the problem of crack detection and demonstrating sensitivity to vertical cracks. It also provides high imaging accuracy for the circular link chain.

Description

Technical Field

[0001] This invention belongs to the field of online monitoring technology for mining scraper conveyors, and relates to an online monitoring device and method for the status of the circular link chain of a mining scraper conveyor. Background Technology

[0002] Scraper conveyors are one of the key pieces of equipment in modern underground coal mining operations, and their safe operation is a crucial factor determining whether a coal mine can operate normally. With the development of modern underground coal mines, scraper conveyors are being laid for increasingly longer lengths and have higher conveying power. However, the circular link chain is the least reliable key component in a scraper conveyor, making online monitoring of the circular link chain essential for ensuring the safe operation of the scraper conveyor.

[0003] The primary failure mode of circular link chains is chain breakage. Chain breakage is caused by two main factors: firstly, wear and plastic deformation at the meshing point between the chain link and the sprocket teeth; and secondly, the formation and development of micro-cracks during chain use. These two factors lead to a decrease in the breaking strength of the circular link chain during service, resulting in chain breakage accidents and causing significant economic losses and risks to equipment and personal safety.

[0004] Currently, methods for monitoring the condition of circular link chains are as follows: Chinese patents (CN118387559A, CN115818158A) disclose methods for online acquisition of circular link chain images using machine vision and analysis of the chain's condition using these images. However, this method suffers from limitations due to residual coal affecting the chain, making it difficult to obtain high-quality images. More importantly, the areas of the chain and sprocket meshing failure are obstructed because they face downwards towards the scraper conveyor's middle plate, thus preventing image acquisition. Furthermore, the camera's image resolution is insufficient to detect minute cracks or internal chain cracks. Therefore, this type of visual monitoring can only monitor the state after chain breakage and more obvious faults such as scraper misalignment and chain stacking. It lacks direct and effective control over chain breakage accidents. Chinese patent CN119429571A proposes using a stereo camera to acquire three-dimensional image information of the circular link chain as a model for scraper conveyor chain monitoring. However, for the same reasons, this method cannot effectively monitor the state before a chain breakage accident because it cannot obtain information about the damaged areas and cracks in the chain-sprocket meshing. Chinese patents (CN116803867A, CN118183218A) relate to the identification and capture of the state after the chain has broken, thereby stopping the scraper conveyor and preventing the accident from escalating further.

[0005] For the reasons mentioned above, there is an urgent need for a method to monitor the condition of circular links chains, which can promptly monitor cracks and damage before a chain breakage accident. Summary of the Invention

[0006] In order to detect damage and cracks in the circular link chain before chain breakage, this invention aims to provide an online monitoring device and method for the condition of the circular link chain in a mining scraper conveyor.

[0007] This invention provides an online monitoring device for the status of the circular link chain of a mining scraper conveyor, comprising a support frame, an X-ray source detector, an X-ray source emitter, a light source base, and a rotary encoder;

[0008] The entire device is installed at the tail end of the scraper conveyor. A support frame, an inverted U-shaped frame, is fixed to the tail end of the scraper conveyor and supports the various components of the monitoring device. An X-ray source detector is installed above the circular chain, fitted to the lower surface of the support frame, to receive the transmission signal formed after X-rays penetrate the circular chain. An X-ray source emitter is installed below the middle plate at the tail end, opposite the X-ray source detector. The X-ray source emitter is fixedly mounted via a light source base and emits X-rays upwards.

[0009] To allow X-rays to pass smoothly through the middle plate and irradiate the circular chain, a transmission window is provided on the middle plate at the position corresponding to the X-ray source. This window contains a polytetrafluoroethylene (PTFE) plate that transmits X-rays, keeping the surface of the middle plate flat. This ensures the continuity and smoothness of the middle plate of the scraper conveyor, without affecting the normal operation of the scraper and the material.

[0010] To obtain displacement information of the circular chain in the running direction, a rotary encoder is installed on the sprocket shaft. The rotary encoder is used to detect changes in the rotation angle of the sprocket shaft in real time.

[0011] A power supply and a computer are located on top of the support frame. The computer is connected to the rotary encoder and the X-ray source detector. The power supply provides power to the X-ray source detector, the computer, and the rotary encoder through a second power line, a third power line, and a first power line. The rotary encoder transmits the detected angle change information to the computer via signal lines, and the X-ray source detector transmits the acquired image data to the computer for processing via signal lines.

[0012] This invention provides a method for online monitoring of the status of the circular link chain in a mining scraper conveyor, comprising the following steps:

[0013] The first step involves the circular chain operating normally. A rotary encoder on the sprocket shaft triggers a photograph based on constant displacement. During the meshing process between the circular chain and the sprocket, a polygonal effect occurs, causing the instantaneous running speed to change periodically. If a fixed time interval is used for line scanning, it can easily lead to stretching or compression distortion of the image in the chain's running direction. Therefore, this invention uses an absolute rotary encoder mounted on the sprocket shaft to monitor the sprocket rotation angle in real time and convert the sprocket angle increment into the displacement increment of the circular chain, thus achieving line scanning triggered by displacement.

[0014] The second step is to perform edge sharpening and contrast enhancement preprocessing on the formed two-dimensional transmission image to improve the recognizability of the circular ring chain boundary and defect area.

[0015] The third step is to assess the wear of the circular link chain at the meshing position with the sprocket, and the depth and extent of the damage are determined by the difference between the gray value of this area and the gray value of other normal areas of the circular link chain.

[0016] Cracks inside a circular chain appear as strip-shaped or line-shaped grayscale anomalies in a two-dimensional image. Their length and shape in the image are used to characterize the size and depth of the crack.

[0017] Fourthly, the above-mentioned wear and crack identification can also be performed using the YOLO target detection algorithm to automatically identify and classify the wear areas and crack images in the two-dimensional transmission image.

[0018] The first step, the specific scanning process, is as follows:

[0019] Let θ be the rotation angle of the sprocket during the k-th encoder read. k The angle increment between two consecutive reads is:

[0020]

[0021] in, This represents the sprocket's rotation angle increment during the kth sampling period.

[0022] The sprocket pitch circle radius is R, and the number of sprocket teeth is N. Considering the polygonal effect, the displacement increment of the circular chain along the running direction within this angular increment is... It can be represented as:

[0023]

[0024] exist In very small cases, γ k Approximately equal to β k ,therefore:

[0025]

[0026] in, This represents the displacement increment of the inner circular chain at the k-th angular step.

[0027] R is the distance from the center point of the regular polygon to one of its endpoints;

[0028] β k γ represents the angle (phase angle) between the tangential velocity direction at the sprocket pitch circle and the linear running direction of the chain at the k-th sampling time. kThis represents the angle between the line connecting the sprocket apex and the horizontal direction at the k-th and (k-1)-th sampling times.

[0029] The β k It can be determined by the periodic relationship between the current rotation angle of the sprocket and the tooth pitch angle β, and its expression is:

[0030]

[0031] in, θ is the tooth pitch angle, and N is the number of sprocket teeth. `wrap` represents the modulus operation, indicating that the angle θ detected by the encoder in real time is used to perform the modulus operation. k Map the complementary angle to [0, β), and calculate the phase angle β at this point. k ,ensure , will β k Substitute into the formula At the same time, combined The conclusion is At this point, ΔS is calculated. k The encoder increment Δθ is converted into displacement increment ΔS. k The displacement calculation process accurately reflects the displacement fluctuations caused by the polygonal effect of the sprocket.

[0032] The cumulative displacement of the circular chain is obtained by summing the displacement increments:

[0033]

[0034] Among them, S k This represents the cumulative displacement of the circular chain along the running direction up to the kth sampling point.

[0035] During the detection process, the spatial sampling interval along the running direction of the circular chain is pre-set as follows: When the cumulative displacement S k achieve At that time, the linear array detector is triggered to perform a line scan and acquire the nth line scan data; where n represents the nth linear array scan.

[0036] The linear array detector outputs one line of pixel data each time it is triggered. Arranging the line scans line by line in the trigger sequence forms a two-dimensional transmission image in a circular chain. For ease of subsequent processing, a certain number of lines are pre-defined as one two-dimensional image, and the next line forms another image.

[0037] By using the above-mentioned equal displacement triggering method, even if the running speed of the circular chain changes due to the polygon effect, the spatial sampling of the two-dimensional image in the direction of chain running still maintains equal spacing, thereby ensuring the geometric consistency of the imaging.

[0038] The beneficial effects of this invention are:

[0039] This invention proposes to use X-ray scanning to obtain damage and cracks in circular link chains. Compared with visual imaging, its advantages are: (1) X-ray uses transmission imaging, so the damaged part of the circular link chain meshing with the sprocket can be imaged even on the back of the detector; this provides conditions for further evaluation of the strength impact of the damage at this location; (2) X-ray scanning imaging solves the problem of crack detection. Since the circular link chain is only sensitive to cracks in the vertical links, and vertical cracks are also prone to occur during manufacturing and use, X-ray scanning is most sensitive to vertical crack detection; (3) X-ray is not sensitive to residual coal and slurry, and has high imaging accuracy for circular link chains. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the online monitoring device for the status of the circular link chain of a mining scraper conveyor according to the present invention;

[0041] Figure 2 This is a schematic diagram of the internal structure of a scraper conveyor;

[0042] Figure 3 This is a schematic diagram of the online monitoring device for the circular link chain status of a mining scraper conveyor according to the present invention.

[0043] Figure 4 A polygonal effect diagram of the sprocket;

[0044] Figure 5 A schematic diagram for calculating chain speed using the sprocket rotation angle;

[0045] Figure 6 This is a process diagram of the online monitoring method for the status of the circular link chain in a mining scraper conveyor according to the present invention;

[0046] Figure 7 This is a grayscale distribution curve obtained from a single linear array scan in an embodiment of the present invention;

[0047] Figure 8 This is a two-dimensional transmission image formed by stitching together multiple X-ray array scan data in an embodiment of the present invention;

[0048] Figure 9 This is a diagram showing the results of identifying defects in a circular chain based on the YOLOv8 target detection model in an embodiment of the present invention.

[0049] In the diagram: 1 is the support frame, 2 is the tail of the scraper conveyor, 3 is the circular chain, 4 is the X-ray detector, 5 is the middle plate, 6 is the light source base, 7 is the X-ray emitter, 8 is the polytetrafluoroethylene plate, 9 is the sprocket shaft, 10 is the rotary encoder, 11 is the power supply, 12 is the computer, 13 is the first signal line, 14 is the first power supply line, 15 is the second signal line, 16 is the second power supply line, 17 is the third power supply line, and 18 is the X-ray. Detailed Implementation

[0050] The present invention will be further illustrated by the following embodiments, but is not limited to the following embodiments.

[0051] Example:

[0052] like Figures 1-2 As shown, this embodiment provides an online monitoring device for the status of the circular link chain of a mining scraper conveyor, including a support frame 1, an X-ray source detector 4, an X-ray source emitter 7, a light source base 6, and a rotary encoder 10;

[0053] The entire device is installed at the tail end 2 of the scraper conveyor. A support frame 1, an inverted U-shaped support frame, is fixed to the tail end 2 of the scraper conveyor and supports the various components of the monitoring device. An X-ray source detector 4 is installed above the circular chain 3, fitted to the lower surface of the support frame 1 and secured with screws. It receives the transmission signal formed after X-rays penetrate the circular chain. An X-ray source emitter 7 is installed below the middle plate 5 at the tail end, opposite the X-ray source detector 4. The X-ray source emitter 7 is fixedly installed via a light source base 6 and emits X-rays upwards.

[0054] To allow X-rays to pass smoothly through the middle plate 5 and irradiate the circular chain 3, a transmission window is provided on the middle plate 5 at the position corresponding to the X-ray source. A polytetrafluoroethylene plate 8 that can transmit X-rays is embedded in this window, keeping the surface of the middle plate flat, thereby ensuring the continuity and smoothness of the middle plate of the scraper conveyor and not affecting the normal operation of the scraper and materials.

[0055] To obtain the displacement information of the circular chain 3 in the running direction, a rotary encoder 10 is installed on the sprocket shaft 9. The rotary encoder 10 is used to detect the angular change of the sprocket shaft in real time.

[0056] A power supply 11 and a computer 12 are located on top of the support frame 1. The power supply 11 supplies power to the X-ray source detector 4, the computer 12, and the rotary encoder 10 through the second power line 16, the third power line 17, and the first power line 14, respectively. The X-ray source detector 4 transmits the acquired image data to the computer 12 for processing through the first signal line 13, and the rotary encoder 10 transmits the detected angle change information to the computer 12 through the second signal line 15.

[0057] The working principle of this invention is as follows: Figure 3 As shown:

[0058] 1. An X-ray source emits a fan-shaped X-ray 18, with a fan angle α that allows the X-ray 18 to cover the area of ​​the two circular chains 3. After passing through the circular chains 3, the X-ray 18 forms an image on the X-ray source detector 4.

[0059] When X-rays penetrate the circular chain, their attenuation in the material follows an exponential decay relationship, and the transmission intensity can be expressed as:

[0060]

[0061] in:

[0062] I0 is the intensity of the X-rays before they hit the circular chain;

[0063] I represents the intensity of the X-rays reaching the detector after penetrating the circular chain;

[0064] μ is the linear attenuation coefficient of the circular link chain steel at the corresponding X-ray energy;

[0065] x represents the effective penetration thickness of X-rays inside the circular chain.

[0066] According to formula (1), the image grayscale of the circular chain formed on the detector is related to the effective penetration thickness of the circular chain. Therefore, when the circular chain wears down during meshing with the sprocket, the local thickness of the circular chain decreases. Let the reduced equivalent thickness be... Then the intensity of the transmitted rays at that point becomes:

[0067]

[0068] In the formula, I wear This indicates the intensity of transmitted rays at the corresponding location when the circular link chain is worn or cracked.

[0069] As can be seen from equation (2), the reduction in thickness caused by wear of the circular chain 3 will cause an increase in the intensity of transmitted rays, which will be reflected in the image of the detector 4 as a change in the gray level of the corresponding area.

[0070] When a crack exists inside the circular chain 3, part of the path of X-ray 18 changes from steel to air or a low-density medium within the crack region, which can be equivalent to a reduction in the thickness of the steel it penetrates. The intensity change of the transmitted rays also satisfies equation (2). Therefore, cracks appear as locally continuous or discontinuous grayscale anomalies in transmission images, and their length and distribution can be used to detect the size and extent of cracks.

[0071] Furthermore, since the polytetrafluoroethylene plate 8 has extremely weak absorption capacity for X-rays, X-rays 18 can almost completely penetrate the plate, and its influence on the circular chain image formed on the X-ray source detector 4 can be ignored.

[0072] This invention provides a method for online monitoring of the condition of the circular link chain in a mining scraper conveyor, such as... Figure 6 As shown, it includes the following steps:

[0073] In the first step, the circular chain 3 operates normally. The encoder on the sprocket shaft 9 triggers the image to be taken at the same displacement. During the meshing process between the circular chain and the sprocket, there is a polygonal effect, which causes the instantaneous running speed to change periodically. If a fixed time interval is used for line scanning, it is easy to cause stretching or compression distortion of the image in the direction of chain running. Therefore, this invention uses an absolute rotary encoder installed on the sprocket shaft 9 to monitor the sprocket rotation angle in real time and convert the sprocket angle increment into the displacement increment of the circular chain to realize line scanning triggered by displacement.

[0074] The linear array detector acquires X-ray transmission line scan data for one circular chain each time it is triggered. As the circular chain moves, it continuously acquires multiple line scan data, and the acquired line scan data is buffered and counted.

[0075] When the number of line scan data reaches the preset number of rows, the line scan data are arranged row by row in the order of acquisition to generate a two-dimensional X-ray transmission image of the circular chain; if the preset number of rows is not reached, the line scan data acquisition continues.

[0076] The second step involves preprocessing the formed two-dimensional transmission image by sharpening the edges and enhancing the contrast to improve the recognizability of the circular chain boundary and defect areas.

[0077] The third step is to assess the depth and extent of damage caused by wear on the circular chain at the meshing point with the sprocket, since the image grayscale value is directly related to the thickness of the material penetrated by X-rays. This is done by comparing the grayscale value of the area with that of other normal areas of the circular chain.

[0078] Cracks inside a circular chain appear as strip-shaped or line-shaped grayscale anomalies in a two-dimensional image. Their length and shape in the image are used to characterize the size and depth of the crack.

[0079] Fourthly, the above-mentioned wear and crack identification can also be performed using the YOLO target detection algorithm to automatically identify and classify the wear areas and crack images in the two-dimensional transmission image.

[0080] The first step, the specific scanning process, is as follows:

[0081] like Figure 4 and Figure 5 As shown, let θ be the rotation angle of the sprocket when the encoder is read for the kth time. k The angle increment between two consecutive reads is:

[0082]

[0083] in, This represents the sprocket's rotation angle increment during the kth sampling period.

[0084] like Figure 5As shown: The sprocket pitch circle radius is R, and the number of sprocket teeth is N. Considering the polygonal effect, the displacement increment of the circular chain along the running direction within this angular increment is... It can be represented as:

[0085]

[0086] exist In very small cases, γ k Approximately equal to β k ,therefore:

[0087]

[0088] in, This represents the displacement increment of the inner circular chain at the k-th angular step.

[0089] R is the distance from the center point of the regular polygon to one of its endpoints;

[0090] β k γ represents the angle (phase angle) between the tangential velocity direction at the sprocket pitch circle and the linear running direction of the chain at the k-th sampling time. k This represents the angle between the line connecting the sprocket apex and the horizontal direction at the k-th and (k-1)-th sampling times.

[0091] The phase angle β k The relationship between the current rotation angle of the sprocket and the periodicity of the tooth pitch angle β is determined by the following expression:

[0092]

[0093] in, θ is the tooth pitch angle, and N is the number of sprocket teeth. `wrap` represents the modulus operation, indicating that the angle θ detected by the encoder in real time is used to perform the modulus operation. k Map the complementary angle to [0, β), and calculate the phase angle β at this point. k ,ensure , will β k Substitute into the formula At the same time, combined The conclusion is At this point, ΔS is calculated. k The encoder increment Δθ is converted into displacement increment ΔS. k Equation (5) can accurately reflect the displacement fluctuations caused by the polygon effect.

[0094] The cumulative displacement of the circular chain is obtained by summing the displacement increments:

[0095]

[0096] Among them, S kThis represents the cumulative displacement of the circular chain along the running direction up to the kth sampling point.

[0097] During the detection process, the spatial sampling interval along the running direction of the circular chain is pre-set as follows: When the cumulative displacement S k achieve At time (n represents the nth trigger linear array scan), the linear array detector is triggered to perform a line scan and acquire the nth line scan data.

[0098] The linear array detector outputs one line of pixel data each time it is triggered. Arranging the line scans line by line in the trigger sequence forms a two-dimensional transmission image in a circular chain. For ease of subsequent processing, a certain number of lines are pre-defined as one two-dimensional image, and the next line forms another image.

[0099] By using the above-mentioned equal displacement triggering method, even if the running speed of the circular chain changes due to the polygon effect, the spatial sampling of the two-dimensional image in the direction of chain running still maintains equal spacing, thereby ensuring the geometric consistency of the imaging.

[0100] This embodiment uses the defect detection of chain links in a scraper conveyor as an example. The chain speed is 1.4 m / s, and the nominal size and pitch of the chain links are 42 × 146 mm.

[0101] The detection system in this embodiment includes a rotary encoder, an X-ray source, an X-ray source detector, and an industrial computer. The rotary encoder is mounted on the sprocket shaft of the scraper conveyor to collect sprocket rotation angle information; the X-ray source and X-ray source detector are respectively arranged on both sides of the chain link for X-ray imaging; the industrial computer is used to receive signals from the rotary encoder, control the triggering of the X-ray source, and perform image processing and defect identification.

[0102] The main hardware devices and parameters used in this embodiment are as follows:

[0103] (1) Rotary encoder

[0104] The rotary encoder used in this embodiment is a Baumer HMG10-B-CANopen. This encoder uses the magnetic induction measurement principle and has a single-turn resolution of 13 bits (8192 positions / turn). Based on a sprocket diameter of 180 mm, the theoretical circumferential displacement corresponding to each encoded position is approximately: π×180 / 8192 ≈ 0.069 mm. Therefore, it meets the requirements for sprocket angle acquisition and chain displacement calculation. The encoder is connected to an industrial computer via the CANopen bus and calculates the chain link displacement based on the sprocket polygon effect.

[0105] (2) X-ray detection system

[0106] This embodiment uses an industrial X-ray inspection device to perform radiographic inspection of the chain links. The X-ray inspection system includes an X-ray source and an X-ray source detector.

[0107] The parameters of the X-ray inspection system can be determined according to the actual inspection equipment. In this embodiment, they are set as follows:

[0108] X-ray source parameters: Brand and model: comet (Switzerland); Model: XRS-600; Setting parameters: Tube voltage 600kV; Tube current: 10 mA.

[0109] (3) X-ray source detector parameters:

[0110] Brand and Model: X-Card from Detection Technology, with a detector resolution of 0.4mm.

[0111] The monitoring process in this embodiment is as follows:

[0112] During the operation of the scraper conveyor, the industrial computer acquires the sprocket rotation angle information output by the rotary encoder in real time, and calculates the chain link displacement based on the polygonal effect of the sprocket.

[0113] When the calculated chain movement distance reaches the set trigger distance (the distance the chain needs to move for X-ray trigger linear array scanning), the industrial computer sends a trigger signal to the X-ray source, causing the X-ray source to emit X-rays, with an exposure time of 0.1ms.

[0114] After X-rays penetrate the chain, they reach the X-ray source detector. The detector converts the received X-ray intensity into grayscale data, forming a sequence of grayscale values ​​arranged along the scanning direction. This sequence of grayscale values ​​is then plotted as a grayscale distribution curve, such as... Figure 7 As shown in the figure, the black lines represent grayscale values.

[0115] The multiple bumps appearing in the grayscale curve are the locations where the grayscale value increases, that is, the grayscale change characteristics formed when the X-ray scan reaches the location of the chain structure.

[0116] As the scraper conveyor continues to operate, when the chain link travels a distance that reaches the set trigger distance again, the X-ray source is triggered to emit X-rays again, thereby continuously acquiring multiple sets of grayscale data.

[0117] Once the number of collected data sets reaches the preset limit, the grayscale data sets are stitched together in the order of collection to form a chain of X-ray images, such as... Figure 8 As shown, the outer contour of the chain link can be observed, and its boundary position corresponds to the area with obvious grayscale changes. Due to the use of equal displacement trigger sampling, the chain link structure maintains a uniform proportion. It can be seen that the scanning method used in this invention can effectively obtain X-ray transmission images with clear structure and good continuity.

[0118] The stitched image is preprocessed, including image denoising, edge sharpening, and contrast enhancement, and then input into the trained YOLOv8 object detection model for defect identification. The identification results are as follows: Figure 9 As shown, by Figure 9 As can be seen, the image contains two parallel circular chains. The upper chain represents a normal chain, while the lower chain represents a defective chain. The upper normal chain exhibits a uniform grayscale distribution, clear boundaries between chain segments, and no obvious abrupt grayscale changes; therefore, the YOLOv8 object detection model did not label it as a defect. The lower chain, however, shows strip-shaped grayscale anomalies in the cracked area. The YOLOv8 model can effectively detect this type of crack defect and accurately pinpoint its location.

[0119] At the same time, due to Figure 9 The image was acquired using X-ray imaging, so the image quality is not affected by dust, water mist, or ambient light at the scene, resulting in high image quality and high monitoring reliability.

[0120] In summary, the monitoring device and method provided by the present invention can also be applied to the monitoring of faults such as complete breakage of circular chain, chain stacking, and broken scraper.

Claims

1. An online monitoring device for the condition of a circular link chain in a mining scraper conveyor, characterized in that, Includes a support frame, X-ray detector, X-ray emitter, light source base, and rotary encoder; A support frame, an inverted U-shaped support frame, is fixed to the tail of the scraper conveyor and is used to support the various components of the monitoring device. An X-ray source detector is installed above the circular chain and is fitted to the lower surface of the support frame to receive the transmission signal formed after X-rays penetrate the circular chain. An X-ray source emitter is installed opposite the X-ray source detector on the middle plate below the tail and is fixedly installed by a light source base. The X-ray source emitter is used to emit X-rays upwards. A rotary encoder is installed on the sprocket shaft to detect changes in the rotation angle of the sprocket shaft in real time.

2. The online monitoring device for the status of the circular link chain of a mining scraper conveyor according to claim 1, characterized in that, A transmission window is provided on the middle plate at the position corresponding to the X-ray source. A polytetrafluoroethylene plate that can transmit X-rays is embedded in the transmission window, so that the surface of the middle plate remains flat and does not affect the normal operation of the scraper and the material.

3. The online monitoring device for the status of the circular link chain of a mining scraper conveyor according to claim 1, characterized in that, A power supply and a computer are located on the top of the support frame. The computer is connected to the rotary encoder and the X-ray source detector. The power supply supplies power to the X-ray source detector, the computer, and the rotary encoder through the second power line, the third power line, and the first power line, respectively.

4. The online monitoring device for the status of the circular link chain of a mining scraper conveyor according to claim 1, characterized in that, The rotary encoder transmits the detected angle change information to the computer via signal lines, and the X-ray detector transmits the acquired image data to the computer for processing via signal lines.

5. A method for online monitoring of the condition of a circular link chain in a mining scraper conveyor, comprising the online monitoring device for the condition of a circular link chain in a mining scraper conveyor as described in any one of claims 1 to 4, characterized in that... Includes the following steps: The first step involves the circular chain operating normally. A rotary encoder on the sprocket shaft triggers a photograph based on constant displacement. During the meshing process between the circular chain and the sprocket, a polygonal effect occurs, causing the instantaneous running speed to change periodically. An absolute rotary encoder mounted on the sprocket shaft is used to monitor the sprocket rotation angle in real time and convert the sprocket angle increment into the displacement increment of the circular chain, thus achieving line scanning triggered by displacement. The second step is to perform edge sharpening and contrast enhancement preprocessing on the formed two-dimensional transmission image to improve the recognizability of the circular ring chain boundary and defect area. The third step is to assess the wear of the circular link chain at the meshing position with the sprocket, and the depth and extent of the damage are determined by the difference between the gray value of this area and the gray value of other normal areas of the circular link chain. Fourthly, the above-mentioned wear and crack identification can also be performed using the YOLO target detection algorithm to automatically identify and classify the wear areas and crack images in the two-dimensional transmission image.

6. The online monitoring method for the status of the circular link chain of a mining scraper conveyor according to claim 5, characterized in that, The specific scanning process in the first step is as follows: Let θ be the rotation angle of the sprocket during the k-th encoder read. k The angle increment between two consecutive reads is: in, This represents the sprocket's rotation angle increment during the kth sampling period; The sprocket pitch circle radius is R, and the number of sprocket teeth is N; considering the polygonal effect, the displacement increment of the circular chain along the running direction within this angular increment is... Represented as: exist In very small cases, γ k Approximately equal to β k ,therefore: in, This represents the displacement increment of the inner circular chain at the k-th angular step. R is the distance from the center point of the regular polygon to one of its endpoints; β k γ represents the angle between the tangential velocity direction at the sprocket pitch circle and the linear running direction of the chain at the k-th sampling time. k This represents the angle between the line connecting the sprocket apex and the horizontal direction at the k-th and (k-1)-th sampling times. The cumulative displacement of the circular chain is obtained by summing the displacement increments: Among them, S k This represents the cumulative displacement of the circular chain along the running direction up to the kth sampling point; During the detection process, the spatial sampling interval along the running direction of the circular chain is pre-set as follows: When the cumulative displacement S k achieve At that time, the linear array detector is triggered to perform a line scan and acquire the nth line scan data; where n represents the nth linear array scan.

7. The online monitoring method for the condition of the circular link chain of a mining scraper conveyor according to claim 6, characterized in that, The β k The relationship between the current rotation angle of the sprocket and the periodicity of the tooth pitch angle β is determined by the following expression: in: θ represents the tooth pitch angle, N is the number of sprocket teeth; wrap represents the modulus operation, indicating that the angle θ detected by the encoder in real time is used to calculate the modulus. k Map the complementary angle to [0, β), and calculate the phase angle β at this point. k ,ensure , will β k Substitute into the formula At the same time, combined The conclusion is At this point, ΔS is calculated. k The encoder increment Δθ is converted into displacement increment ΔS. k The displacement calculation process accurately reflects the displacement fluctuations caused by the polygonal effect of the sprocket.

8. The online monitoring method for the status of the circular link chain of a mining scraper conveyor according to claim 7, characterized in that, The linear array detector outputs a line of pixel data each time it is triggered. The line scans are arranged line by line according to the triggering order to form a two-dimensional transmission image of a circular chain.

9. The online monitoring method for the condition of the circular link chain of a mining scraper conveyor according to claim 5, characterized in that, In the third step, the internal cracks of the circular chain appear as strip-shaped or line-shaped gray-scale anomalies in the two-dimensional image, and their length and shape in the image are used to characterize the size and depth of the cracks.

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