Underground belt conveyor speed regulation control system and method based on vision assistance

Abstract

The invention discloses an underground belt conveyor speed regulation control system and method based on vision assistance, and the system comprises an image collection device which is used for collecting a coal flow image; the ground control center is used for obtaining a coal flow detection result according to the coal flow image; the driving device is used for driving a belt of the belt conveyor to move; the speed regulation control device is connected with the explosion-proof frequency converter, and the speed regulation control device is used for adjusting the running speed of the belt conveyor according to the coal flow detection result; and the comprehensive protection device is connected with the speed regulation control device, and the comprehensive protection device is used for monitoring the running state of the belt conveyor. Real-time coal flow is calculated based on machine vision, and according to the change state of the coal flow, the PLC control unit adjusts the rotating speed of the explosion-proof motor by controlling the explosion-proof frequency converter, so that the running speed of the belt conveyor can be automatically adjusted according to the coal flow, and the optimized energy-saving control of the mine coal conveying system is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of underground belt conveyors, and in particular to a visually assisted underground belt conveyor speed control system and a control method. Background Art

[0002] Most of the belt conveyors in coal mines use explosion-proof frequency converters as soft-start drive units. However, during the stable operation stage, the frequency converter does not adjust the speed of the belt conveyor, but keeps running at the industrial power frequency. It is impossible to achieve variable frequency speed control according to changes in the load coal volume, which greatly affects the economic operation of the coal flow transportation system.

[0003] To achieve variable frequency control of belt conveyors, the key is to accurately detect the coal flow on the belt conveyor in real time and to safely control the coal flow with variable frequency speed control. Traditional coal flow detection mainly uses electronic tape scales, nuclear tape scales, etc. to weigh the coal on the belt, which requires a large installation space, complex equipment maintenance, and low safety and reliability. With the popularization and application of image processing methods, visual-assisted coal flow detection methods have emerged. However, due to the particularity of the underground environment of coal mines, traditional image processing methods cannot fully and effectively detect coal flow, which poses more challenges to the realization of variable frequency control of belt conveyors.

[0004] Therefore, exploring a new method for detecting the coal flow on belt conveyors that is suitable for underground coal mine environments, and then realizing automatic adjustment of the belt conveyor operating speed according to the coal flow, is of great significance for reducing equipment wear and energy consumption, and is an urgent need for the efficient and economical operation of mine coal transportation systems. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a speed control system and a control method for an underground belt conveyor based on vision assistance.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a visually assisted underground belt conveyor speed control system, comprising:

[0007] An image acquisition device is arranged above the belt conveyor and is used to acquire coal flow images; the image acquisition device transmits the coal flow images to a ground control center through a ring network exchange cabinet; the ground control center is used to obtain coal flow detection results according to the coal flow images;

[0008] A driving device, comprising: an explosion-proof motor and an explosion-proof frequency converter, wherein the explosion-proof motor is connected to the belt conveyor, the explosion-proof frequency converter is connected to the explosion-proof motor, and the driving device is used to drive the belt of the belt conveyor to move;

[0009] A speed control device, the speed control device is connected to the explosion-proof frequency converter, and the speed control device is used to adjust the running speed of the belt conveyor according to the coal flow detection result;

[0010] A comprehensive protection device is connected to the speed control device, and is used to monitor the operating status of the belt conveyor.

[0011] Furthermore, the speed control device includes: a PLC control unit, a digital input unit, an analog input unit, a power supply, a communication unit and a power monitoring unit. The PLC control unit is connected to the explosion-proof inverter through the communication unit, the digital input unit and the analog input unit are both connected to the comprehensive protection device, the power monitoring unit is connected to the explosion-proof motor, and the power supply is used for power supply.

[0012] The present invention also provides a control method for an underground belt conveyor speed control system based on visual assistance, which is characterized by comprising the following steps:

[0013] S1. During the operation of the belt conveyor, the image acquisition device is used to collect coal flow images in real time, and the images are transmitted to the ground control center through the ring network exchange cabinet;

[0014] S2, the ground control center processes the coal flow image to obtain the coal flow at the current moment;

[0015] S3. Send the calculated coal flow rate to the speed control device, and the speed control device performs speed control on the belt conveyor according to the coal flow rate.

[0016] Furthermore, in step S2, the coal flow at the current moment is obtained, including:

[0017] Obtaining the complete laser stripe center line of the belt conveyor in an unloaded state and a fully loaded state; and obtaining the complete laser stripe center line of the belt conveyor in a loaded state;

[0018] Calculate the number of pixel points N in the closed envelope formed by the superposition of the center line of the laser stripe in the no-load state and the center line of the laser stripe in the loaded state;

[0019] Calculate the number of pixel points M in the closed envelope formed by the superposition of the center line of the laser stripe in the no-load state and the center line of the laser stripe in the full-load state;

[0020] Calculate the coal flow ratio P = N / M and calculate the coal flow rate Q at the current moment s =Q*P; Q represents the coal transportation volume when the belt conveyor is fully loaded.

[0021] Furthermore, the speed control device adjusts the running speed of the belt conveyor according to a speed control rule.

[0022] Furthermore, the speed control rule is:

[0023] When 0 s ≤Q min When the belt conveyor belt running speed v = v min ;

[0024] When Q min s ≤Q min +ΔQ s When the belt conveyor belt running speed v = (Q min +ΔQ s ) / 3.6q m ;

[0025] When Q min +ΔQ s s ≤Q min +2ΔQ s , the belt conveyor belt running speed v = (Q min +2ΔQ s ) / 3.6q m ;

[0026] When Q min +2ΔQ s s ≤Q min +3ΔQ s , the belt conveyor belt running speed v = (Q min +3ΔQ s ) / 3.6q m ;

[0027] By analogy, when Q min +(n-1)ΔQ s s ≤Q min +nΔQ s , the belt conveyor belt running speed v = (Q min +nΔQ s ) / 3.6q m ;

[0028] Among them, v min =Q / 3.6q m ,q m Indicates the maximum load-bearing linear density of the belt, ΔQ s Indicates the increase in coal flow, Q min Represents the empirical value of minimum coal flow rate.​​​​​

[0029] Furthermore, in step S2, the coal flow image is processed, including:

[0030] The coal flow image is preprocessed, and the laser stripe center line of the preprocessed coal flow image is extracted to obtain a complete laser stripe center line of the coal flow image.

[0031] Further, the preprocessing includes:

[0032] The coal flow image is converted into a coal flow grayscale image, and the coal flow grayscale image is filtered and smoothed using a bilateral filtering algorithm to obtain a coal flow filtered image;

[0033] The maximum inter-class variance method is used to synthesize the grayscale information of all pixels in the coal flow filtering image, and the image is binarized and segmented by setting a grayscale threshold to obtain a coal flow segmentation image;

[0034] The abnormal light spots in the coal flow segmentation image are removed by a contour search method to obtain a preprocessed image containing only laser stripes.

[0035] Further, the laser stripe centerline extraction includes:

[0036] The geometric center points of the upper and lower edges of the laser stripes in the preprocessed image are extracted in order from left to right and from top to bottom, and the adjacent geometric center points are connected to obtain the complete center line of the laser stripes.

[0037] Furthermore, the speed control rule is stored in the PLC control unit. When the PLC control unit receives the current coal flow rate Q of the belt conveyor, s Then, query the coal flow Q s The corresponding belt running speed is converted into the output frequency of the corresponding explosion-proof inverter, thereby changing the speed of the explosion-proof motor to adjust the running state of the belt conveyor.

[0038] The beneficial effect of the present invention is that the vision-assisted underground belt conveyor speed control system and control method of the present invention utilizes a laser transmitter to assist a high-definition digital camera to obtain real-time coal flow images of the belt conveyor, and calculates the real-time coal flow rate. According to the changing state of the coal flow rate, the PLC control unit adjusts the speed of the explosion-proof motor by controlling the explosion-proof frequency converter, so that the operating speed of the belt conveyor can be automatically adjusted according to the coal flow rate, thereby realizing optimized energy-saving control of the mine coal transportation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0040] Figure 1It is a structural schematic diagram of the underground belt conveyor speed control system based on vision assistance of the present invention.

[0041] Figure 2 It is a schematic diagram of the comprehensive protection device and the speed control device of the present invention.

[0042] Figure 3a It is a schematic diagram of a grayscale image of a coal flow image of the present invention.

[0043] Figure 3b It is a schematic diagram of the coal flow filtering image of the present invention.

[0044] Figure 3c It is a schematic diagram of the coal flow segmentation image of the present invention.

[0045] Figure 3d It is a preprocessed image of the coal flow image of the present invention.

[0046] Figure 3e Schematic diagram of the center line of the laser stripe of the present invention.

[0047] Figure 4 It is a schematic diagram of the coal flow calculation of the present invention.

[0048] In the figure: 1. Belt conveyor; 2. Ring network switching cabinet; 3. Ground control center; 41. Explosion-proof motor; 42. Explosion-proof inverter; 5. Speed ​​control device; 6. Comprehensive protection device; 71. Laser transmitter; 72. High-definition digital camera. DETAILED DESCRIPTION

[0049] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0050] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0051] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0052] like Figure 1 to Figure 2 As shown, the visually assisted underground belt conveyor speed control system of the present invention comprises: an image acquisition device, which is arranged above the belt conveyor 1 and is used to acquire coal flow images; the image acquisition device transmits the coal flow images to the ground control center 3 through the ring network exchange cabinet 2; the ground control center 3 is used to obtain the coal flow detection result according to the coal flow image. A driving device, comprising: an explosion-proof motor 41 and an explosion-proof frequency converter 42, the explosion-proof motor 41 is connected to the belt conveyor 1, the explosion-proof frequency converter 42 is connected to the explosion-proof motor 41, and the driving device is used to drive the belt of the belt conveyor 1 to move. A speed control device 5, the speed control device 5 is connected to the explosion-proof frequency converter 42, and the speed control device 5 is used to adjust the running speed of the belt conveyor 1 according to the coal flow detection result. A comprehensive protection device 6, the comprehensive protection device 6 is connected to the speed control device 5, and the comprehensive protection device 6 is used to monitor the running state of the belt conveyor 1.

[0053] It should be noted that the image acquisition device includes: a laser emitter 71 and a high-definition digital camera 72. The laser emitter 71 is vertically irradiated on the belt of the belt conveyor 1. The laser emitter is about 1m to 1.2m away from the belt, so that the laser stripes can cover the entire width of the belt. The high-definition digital camera 72 is located about 0.9m to 1m above the belt conveyor 1 and forms a certain angle with the vertical direction, so that the laser stripes of the belt conveyor 1 when it is empty and fully loaded can be located at a suitable position close to the center of the image. As the belt transports coal, the image acquisition device can collect coal flow images in real time, and the coal flow images contain belts, coal and laser stripes.

[0054] Specifically, the speed control device 4 includes: a PLC control unit, a digital input unit, an analog input unit, a power supply, a communication unit and a power monitoring unit. The PLC control unit is connected to the explosion-proof frequency converter 42 through the communication unit. The digital input unit and the analog input unit are both connected to the comprehensive protection device 6. The power monitoring unit is connected to the explosion-proof motor 41. The power supply is used for power supply. The comprehensive protection device 6 includes: a coal pile sensor, a deviation sensor, a tear sensor, a speed sensor, etc., which are used to collect the operating status of the belt conveyor 1 in real time.

[0055] The speed control device 4 is based on the PLC control unit, and is connected to the sensor of the comprehensive protection device 6 through the signal (digital signal and analog signal) input unit to monitor the actual operating state of the belt conveyor 1, and collect the real-time power of the explosion-proof motor 41 through the power monitoring unit. At the same time, the PLC control unit uses the communication module to connect with the explosion-proof inverter 42 to adjust the actual operating speed of the belt conveyor 1 according to the real-time coal flow information sent by the ground control center 3 and the speed control rules. Through innovative improvements, the present invention enables the operating speed of the belt conveyor 1 to be automatically adjusted according to the coal flow, thereby realizing optimized energy-saving control of the mine coal transportation system.

[0056] The present invention also provides a control method for an underground belt conveyor speed control system based on visual assistance, comprising the following steps: S1. During the operation of the belt conveyor 1, an image acquisition device is used to collect coal flow images in real time, and the images are transmitted to the ground control center 3 through the ring network exchange cabinet 2. S2. The ground control center 3 processes the coal flow images to obtain the coal flow at the current moment. S3. The calculated coal flow is sent to the speed control device 5, and the speed control device 5 controls the speed of the belt conveyor 1 according to the coal flow.

[0057] Specifically, in step S2, the coal flow image is processed, including: preprocessing the coal flow image, extracting the laser stripe center line of the preprocessed coal flow image, and obtaining the complete laser stripe center line of the coal flow image. The preprocessing includes: converting the coal flow image into a coal flow grayscale image (such as Figure 3a As shown in the figure), the coal flow grayscale image is filtered and smoothed using the bilateral filtering algorithm to obtain the coal flow filtered image (as shown in the figure). Figure 3b As shown in Figure 2 ); the coal flow filtering image uses the grayscale information of all pixels in the c comprehensive image, and the image is binarized by setting the grayscale threshold to obtain the coal flow segmentation image (as shown in Figure 2 ). Figure 3c The abnormal light spots in the coal flow segmentation image are removed by contour search method to obtain a preprocessed image containing only laser stripes (as shown in Figure 3d The laser stripe centerline extraction includes: extracting the geometric center points of the upper and lower edges of the laser stripes in the preprocessed image in a sequence from left to right and from top to bottom, and connecting adjacent geometric center points to obtain a complete laser stripe centerline (as shown in Figure 3e shown).

[0058] It should be noted that filtering and smoothing the coal flow grayscale image can blur a large range of coal flow and belt information and remove noise points in the image, while highlighting the edge information of the laser stripes in the coal flow grayscale image. After the image is binarized and segmented, the information of the laser stripes can be made more obvious. After preprocessing, the preprocessed image only contains laser stripes, but the laser stripes in the preprocessed image are not a complete line. The geometric center points of the upper and lower edges of the laser stripes in the preprocessed image are extracted from left to right and from top to bottom, and the adjacent geometric center points are connected to obtain a complete laser stripe center line. Since the laser triangulation method is applied to large-viewing-range and long-distance measurement tasks, the impact of the size change of the measured object is far greater than the impact of the laser stripe center extraction accuracy on the result, and the measurement resolution requirement is not high. Therefore, the laser stripes with a certain width in the preprocessed image can be directly processed quickly, and the geometric center points of the upper and lower edges of the laser stripes are taken to represent their true center position, and the two adjacent points are connected to finally obtain the laser stripe center line of the belt conveyor 1 under load.

[0059] After extracting the laser stripe center line of the coal flow image, the real-time coal flow rate can be calculated. Obtaining the coal flow rate at the current moment includes: obtaining the complete laser stripe center line of the belt conveyor 1 in the no-load state and the full-load state; and obtaining the complete laser stripe center line of the belt conveyor 1 in the loaded state; calculating the number of pixels N in the closed envelope formed by the superposition of the laser stripe center line in the no-load state and the laser stripe center line in the loaded state; calculating the number of pixels M in the closed envelope formed by the superposition of the laser stripe center line in the no-load state and the laser stripe center line in the full-load state; calculating the coal flow ratio P = N / M, and calculating the coal flow rate Q at the current moment. s =Q*P; Q represents the coal transportation volume of the belt conveyor 1 when it is fully loaded.

[0060] That is to say, the position and shape of the center line of the laser stripes extracted by the belt conveyor 1 in the no-load, loaded and fully loaded states are different. The number of pixel points M contained in the closed envelope formed by the superposition of the center lines of the laser stripes in the no-load state and the fully loaded state can be calibrated in advance. In the process of real-time detection, the number of pixel points N in the closed envelope formed by the superposition of the center lines of the laser stripes in the no-load state and the laser stripes in the loaded state is determined, and the coal flow ratio can be calculated, and then the current coal flow rate can be calculated after conversion. The calculation method of the present invention is simple and fast, and the accuracy of the calculation result is high.

[0061] For example, Figure 4As shown, in order to calculate the coal flow ratio P, first collect the belt image of the belt conveyor 1 in the no-load state, and use the aforementioned laser stripe processing method to process the belt image in the no-load state to obtain the complete laser stripe center line in the no-load state. Then collect the coal flow image of the belt conveyor 1 in the full load (i.e. rated load) state, and use the same laser stripe processing method to process it, and obtain the complete laser stripe center line in the full load (i.e. rated load) state. Then collect the coal flow image of the belt conveyor 1 in the loaded state, and use the same laser stripe processing method to obtain the complete laser stripe center line in the loaded state. Then calculate the number of pixels N in the closed envelope curve formed by the superposition of the complete laser stripe center line in the no-load state and the complete laser stripe center line in the loaded state (i.e. the oblique line shaded area in Figure 3), and the number of pixels M in the closed envelope curve formed by the superposition of the complete laser stripe center line in the no-load state and the complete laser stripe center line in the full load state (i.e. the dotted shaded area in Figure 3), and finally calculate the coal flow ratio P, and then calculate the current coal flow Q s .

[0062] The ground control center 3 calculates the current coal flow Q s Then, the coal flow Q s The PLC control unit stores the speed control rules. When the PLC control unit receives the current coal flow Q of the belt conveyor 1, s Then, query the coal flow Q s The corresponding belt running speed is converted into the output frequency of the corresponding explosion-proof inverter 42, thereby changing the rotation speed of the explosion-proof motor 41 to adjust the running state of the belt conveyor 1.

[0063] Specifically, the speed control rule is: when 0 s ≤Q min When the belt conveyor 1 has a running speed v=v min ; When Q min s ≤Q min +ΔQ s When the belt conveyor 1 has a running speed v = (Q min +ΔQ s ) / 3.6q m ; When Q min +ΔQ s s ≤Q min +2ΔQ s , the belt running speed v of the belt conveyor 1 = (Q min +2ΔQ s ) / 3.6q m ; When Q​​​min +2ΔQ s s ≤Q min +3ΔQ s , the belt running speed v of the belt conveyor 1 = (Q min +3ΔQ s ) / 3.6q m ; Similarly, when Q min +(n-1)ΔQ s s ≤Q min +nΔQ s , the belt running speed v of the belt conveyor 1 = (Q min +nΔQ s ) / 3.6q m Among them, v min =Q / 3.6q m ,q m Indicates the maximum load-bearing linear density of the belt, ΔQ s Indicates the increase in coal flow, Q min Indicates the empirical value of the minimum coal flow rate. If the actual coal flow rate is less than Q min , then the belt running speed of belt conveyor 1 maintains the minimum running speed v min constant.

[0064] That is, the PLC control unit receives the current coal flow Q s After that, the speed control rules can be queried in its own memory to find the coal flow Q s Corresponding belt running speed. When the belt conveyor 1 is unloaded, the belt running speed should be zero. Considering that in the actual production process of the coal mine, the frequent start and stop of the belt conveyor 1 will cause a greater impact on the power grid and cause greater damage to the drive motor, therefore, when the real-time coal flow rate is lower than the empirical value Q min (obtained through experiment), take the minimum design value v of belt running speed min As the belt running speed, considering the dynamic characteristics of the belt conveyor, if it is steplessly regulated, it will affect the service life of the mechanical equipment. In order to avoid disturbance of the coal flow and ensure the safety and stability of the system, the coal flow is divided into n equal intervals ΔQ s , take the minimum belt running speed corresponding to the upper limit value of each coal flow interval as the belt running speed in this section of coal flow interval. For example, when the coal flow Q on the belt conveyor 1 is s Between the interval (Q min +(n-1)ΔQ s ,Q min +nΔQ s ], the belt running speed should be adjusted to (Q min+ nΔQ​​s ) / 3.6q m The speed control rules of the belt conveyor 1 are designed according to the actual operating conditions of the working conditions and are stored in the storage card of the PLC control unit in the form of a table to avoid the loss of the speed control rules due to unexpected power failures, thereby affecting the normal operation of the system. After receiving the real-time coal flow information each time, the PLC control unit determines the desired belt running speed by querying the belt conveyor speed control rule table, and converts the desired belt running speed into the corresponding output frequency of the explosion-proof inverter 42, and adjusts the operating state of the conveyor by changing the actual speed of the explosion-proof motor 41. m Depending on the type of belt used, the number of equal division intervals n of the coal flow rate needs to be determined according to actual application requirements.

[0065] In summary, the vision-assisted underground belt conveyor speed control system and control method of the present invention utilizes a laser transmitter 71 to assist a high-definition digital camera 72 to obtain a real-time coal flow image of the belt conveyor 1, and calculates the real-time coal flow rate. According to the changing state of the coal flow rate, the PLC control unit adjusts the speed of the explosion-proof motor 41 by controlling the explosion-proof frequency converter 42, so that the operating speed of the belt conveyor 1 can be automatically adjusted according to the coal flow rate, thereby realizing optimized energy-saving control of the mine coal transportation system.

[0066] The present invention combines machine vision, PLC control technology and variable frequency speed regulation technology to develop a speed regulation control system and control method for an underground belt conveyor with four dimensions of perception, transmission, decision-making and execution. This changes the state in which the underground belt conveyor always runs at the rated speed, realizes the intelligent perception, autonomous speed regulation and energy-saving operation of the belt conveyor 1, and promotes the intelligent application and development of the belt conveyor 1.

[0067] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A speed control system for underground belt conveyor based on visual assistance, characterized in that: include: An image acquisition device is arranged above the belt conveyor (1) and is used to acquire coal flow images; the image acquisition device transmits the coal flow images to a ground control center (3) through a ring network exchange cabinet (2); The ground control center (3) is used to obtain a coal flow detection result according to the coal flow image; A driving device, comprising: an explosion-proof motor (41) and an explosion-proof frequency converter (42), wherein the explosion-proof motor (41) is connected to the belt conveyor (1), and the explosion-proof frequency converter (42) is connected to the explosion-proof motor (41), and the driving device is used to drive the belt of the belt conveyor (1) to move; A speed control device (5), the speed control device (5) being connected to the explosion-proof frequency converter (42), and the speed control device (5) being used to adjust the running speed of the belt conveyor (1) according to the coal flow detection result; A comprehensive protection device (6), the comprehensive protection device (6) is connected to the speed control device (5), and the comprehensive protection device (6) is used to monitor the operating status of the belt conveyor (1).

2. The visually assisted underground belt conveyor speed control system according to claim 1, characterized in that: The speed control device (4) comprises: a PLC control unit, a digital input unit, an analog input unit, a power supply, a communication unit and a power monitoring unit. The PLC control unit is connected to the explosion-proof frequency converter (42) via the communication unit. The digital input unit and the analog input unit are both connected to the comprehensive protection device (6). The power monitoring unit is connected to the explosion-proof motor (41). The power supply is used for power supply.

3. A control method for a speed control system of an underground belt conveyor based on visual assistance as claimed in claim 2, characterized in that: The following steps are involved: S1, during the operation of the belt conveyor (1), using the image acquisition device to acquire coal flow images in real time, and transmitting the images to the ground control center (3) through the ring network exchange cabinet (2); S2, the ground control center (3) processes the coal flow image to obtain the coal flow at the current moment; S3. Send the calculated coal flow rate to the speed control device (5), and the speed control device (5) controls the speed of the belt conveyor (1) according to the coal flow rate.

4. The control method of the underground belt conveyor speed control system based on visual assistance according to claim 3 is characterized in that: In step S2, the coal flow rate at the current moment is obtained, including: Obtaining the complete laser stripe center line of the belt conveyor (1) in an unloaded state and a fully loaded state; and obtaining the complete laser stripe center line of the belt conveyor (1) in a loaded state; Calculate the number of pixel points N in the closed envelope formed by the superposition of the center line of the laser stripe in the no-load state and the center line of the laser stripe in the loaded state; Calculate the number of pixel points M in the closed envelope formed by the superposition of the center line of the laser stripe in the no-load state and the center line of the laser stripe in the full-load state; Calculate the coal flow ratio P = N / M and calculate the coal flow rate Q at the current moment s =Q*P; Q represents the coal transportation volume of the belt conveyor (1) under full load.

5. The control method of the underground belt conveyor speed control system based on visual assistance according to claim 4 is characterized in that: The speed control device (5) adjusts the running speed of the belt conveyor (1) according to a speed control rule.

6. The control method of the underground belt conveyor speed control system based on visual assistance according to claim 5 is characterized in that: The speed control rule is: When 0 s ≤Q min When the belt conveyor (1) has a belt running speed v=v min ;​ When Q min s ≤Q min +ΔQ s When the belt conveyor (1) has a belt running speed v = (Q min +ΔQ s ) / 3.6q m ;​ When Q min +ΔQ s s ≤Q min +2ΔQ s The belt conveyor (1) has a belt running speed v = (Q min +2ΔQ s ) / 3.6q m ;​ When Q min +2ΔQ s s ≤Q min +3ΔQ s The belt conveyor (1) has a belt running speed v = (Q min +3ΔQ s ) / 3.6q m ;​ By analogy, when Q min +(n-1)ΔQ s s ≤Q min +nΔQ s The belt conveyor (1) has a belt running speed v = (Q min +nΔQ s ) / 3.6q m ;​ Among them, v min =Q / 3.6q m ,q m Indicates the maximum load-bearing linear density of the belt, ΔQ s Indicates the increase in coal flow, Q min Represents the empirical value of minimum coal flow rate.

7. The control method of the underground belt conveyor speed control system based on visual assistance according to claim 6 is characterized in that: In step S2, the coal flow image is processed, including: The coal flow image is preprocessed, and the laser stripe center line of the preprocessed coal flow image is extracted to obtain a complete laser stripe center line of the coal flow image.

8. The control method of the underground belt conveyor speed control system based on visual assistance according to claim 7 is characterized in that: The pre-processing comprises: The coal flow image is converted into a coal flow grayscale image, and the coal flow grayscale image is filtered and smoothed using a bilateral filtering algorithm to obtain a coal flow filtered image; The maximum inter-class variance method is used to synthesize the grayscale information of all pixels in the coal flow filtering image, and the image is binarized and segmented by setting a grayscale threshold to obtain a coal flow segmentation image; The abnormal light spots in the coal flow segmentation image are removed by a contour search method to obtain a preprocessed image containing only laser stripes.

9. The control method of the underground belt conveyor speed control system based on visual assistance according to claim 8, characterized in that: Laser stripe centerline extraction, including: The geometric center points of the upper and lower edges of the laser stripes in the preprocessed image are extracted from left to right and from top to bottom, and the adjacent geometric center points are connected to obtain the complete center line of the laser stripes.

10. The control method of the underground belt conveyor speed control system based on visual assistance according to claim 6, characterized in that: The speed control rule is stored in the PLC control unit. When the PLC control unit receives the current coal flow rate Q of the belt conveyor (1), s Then, query the coal flow Q s The corresponding belt running speed is converted into the output frequency of the corresponding explosion-proof frequency converter (42), thereby changing the rotation speed of the explosion-proof motor (41) to adjust the running state of the belt conveyor (1).

Images