A coal gangue separation system and method based on multi-stage screening and inclined plane separation

Abstract

The application provides a coal and gangue separating system and method based on multi-stage screening and inclined plane separation, and belongs to the field of underground intelligent coal and gangue separation. The system comprises a coal and gangue particle size multi-stage screening subsystem, an inclined plane coal and gangue separating subsystem and a high-precision coal and gangue identifying and separating subsystem. Firstly, the coal and gangue particle size multi-stage screening subsystem performs multi-stage screening according to the particle sizes of coal and gangue, and the screened coal and gangue is conveyed to the inclined plane coal and gangue separating subsystem. Secondly, the inclined plane coal and gangue separating subsystem utilizes the physical characteristic differences of coal and gangue of different particle sizes on the inclined plane belt conveyor, controls the key parameters of the inclined plane belt conveyor, and realizes the preliminary separation of coal and gangue. Finally, the high-precision coal and gangue identifying and separating subsystem adopts a Relief-MRMR-SVM model to accurately identify coal and gangue, controls a mechanical arm to sort, and realizes deep optimization separation. The application realizes the accurate separation of coal and gangue through the three closely coordinated subsystems and methods.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of intelligent coal gangue sorting underground, and in particular to a multi-stage screening and inclined surface separation type coal gangue sorting system and method. BACKGROUND

[0002] The traditional coal gangue sorting method has the problem of low intelligence, which is difficult to meet the green and intelligent transformation of modern coal industry. At present, some coal gangue separation technologies have been proposed and applied, such as physical screening, gravity separation, flotation, etc. However, these technologies often have problems such as unstable separation effect, complex equipment, etc. in actual application, and are easily affected by environmental factors in actual application, which limits the sorting effect and cannot realize comprehensive and fine processing of coal and gangue.

[0003] Some early sorting equipment can only perform simple rough sorting and cannot identify and separate coal and gangue in depth, so that a certain amount of gangue may still be mixed in the sorted coal product, so that the gangue cannot be fully separated and effectively utilized. Therefore, a new type of coal gangue sorting system is urgently needed to solve the problems existing in the prior art, realize intelligent and accurate separation of coal and gangue, improve the efficiency and quality of coal sorting, reduce the labor cost in the sorting process, and has important significance for the rational utilization of coal resources and environmental protection. SUMMARY

[0004] The purpose of the present application is to provide a multi-stage screening and inclined surface separation type coal gangue sorting system and method, which realizes intelligent and accurate separation of coal and gangue by the cooperation of multi-stage screening, inclined surface separation technology, high-precision coal gangue identification model and mechanical arm, and improves the efficiency and quality of sorting.

[0005] To achieve the above purpose, the present application provides a multi-stage screening and inclined surface separation type coal gangue sorting system, which comprises:

[0006] The coal gangue particle size multi-stage screening subsystem comprises one main belt conveyor, one steel plate frame and n screening units; wherein the n screening units are arranged in a ladder shape on the steel plate frame, the ends of the n screening units are connected with the inclined surface coal gangue sorting subsystem, any two adjacent screening units are connected through an inclined channel, each screening unit is provided with one auxiliary belt conveyor, the first n-1 auxiliary belt conveyors are provided with one roller shaft screen, the distance between the roller shafts on the first n-1 auxiliary belt conveyors decreases in turn, and the first screening unit is connected with the main belt conveyor;

[0007] The inclined coal gangue sorting subsystem comprises n descending belt conveyors, n inclined belt conveyors and one programmable logic controller; the end of the descending belt conveyor is connected with the head of the inclined belt conveyor, each inclined belt conveyor is driven by a servo motor and is provided with a force sensor, and the head of each descending belt conveyor is connected with the end of the auxiliary belt conveyor;

[0008] The high-precision coal gangue identification and sorting subsystem comprises n gangue conveying belt conveyors, n coal conveying belt conveyors, one server and one DeltaV distributed control system; wherein the n gangue conveying belt conveyors and the n coal conveying belt conveyors are arranged in sequence along the conveying direction of the n inclined belt conveyors, and the image acquisition equipment and the mechanical arm are arranged on one side of each gangue conveying belt conveyor and coal conveying belt conveyor.

[0009] The application further provides a coal gangue sorting method based on multi-stage screening and inclined separation, which adopts the coal gangue sorting system based on multi-stage screening and inclined separation.

[0010] Step S1, in a trial operation stage, the related equipment of each subsystem and the parameters thereof are adjusted and determined;

[0011] Step S11, the roller spacing of the roller screen in the first n-1 screening units of the coal gangue particle size multi-stage screening subsystem is adjusted, and the roller spacing is sequentially reduced from the first auxiliary belt conveyor to the n-1 auxiliary belt conveyors;

[0012] Step S12, the inclination angle θ of the inclined belt conveyor in the inclined coal gangue sorting subsystem is determined: 0 < θ < min{arctan μ1, arctan μ2}, wherein μ1 represents the friction coefficient of coal on the inclined belt conveyor, and μ2 represents the friction coefficient of gangue on the inclined belt conveyor;

[0013] Step S13, the speed V1 of the inclined belt conveyor in the inclined coal gangue sorting subsystem is determined: V1 > V2, V1 > V3, wherein V2 represents the speed of coal leaving the inclined belt conveyor, and V3 represents the speed of gangue leaving the inclined belt conveyor;

[0014] Step S14, the length S of the inclined belt conveyor in the inclined coal gangue sorting subsystem is determined: Wherein a1 represents the acceleration of coal moving on the inclined belt conveyor, a2 represents the acceleration of gangue moving on the inclined belt conveyor, and V0 represents the speed of coal and gangue reaching the head of the inclined belt conveyor;

[0015] Step S15, the positions of the gangue conveying belt conveyor and the coal conveying belt conveyor in the high-precision coal gangue identification and sorting subsystem are determined: Wherein, L1 represents the distance between the coal gangue belt conveyor and the inclined belt conveyor, L2 represents the distance between the coal belt conveyor and the inclined belt conveyor, and g represents the acceleration of gravity;

[0016] Step S2, the system is formally operated, and the coal and gangue of different particle sizes are screened by the coal gangue particle size multi-level screening subsystem;

[0017] Step S21, the main belt conveyor conveys the coal and gangue to the first screening unit of the coal gangue particle size multi-level screening subsystem;

[0018] Step S22, when the coal and gangue pass through the roller screen on the first screening unit, the coal and gangue larger than the roller spacing pass through the roller screen, and then are conveyed into the inclined coal and gangue separation subsystem through the auxiliary belt conveyor, and the coal and gangue smaller than the roller spacing pass through the roller spacing and finally leak into the next screening unit, and then are screened at the next particle size, until the remaining coal and gangue fall into the nth screening unit;

[0019] Step S3, the inclined coal and gangue separation subsystem preliminarily separates the coal and gangue of the same particle size range;

[0020] Step S31, the coal and gangue of each particle size screened out through step S22 are transitioned to the corresponding inclined belt conveyor through the descending belt conveyor;

[0021] Step S32, the coal and gangue are conveyed to the first end of the corresponding inclined belt conveyor at a speed of V0, and start to make accelerated motion in the inclined direction;

[0022] Step S33, under the difference in physical properties of the coal and gangue of different particle sizes, the coal and gangue make inclined projectile motion with different initial velocities respectively through the speed, length and inclination angle of each inclined belt conveyor, and fall into the coal belt conveyor with a distance L2 from the inclined belt conveyor and the gangue belt conveyor with a distance L1 from the inclined belt conveyor respectively;

[0023] Step S4, the high-precision coal and gangue identification and separation subsystem implements deep optimization separation on the preliminarily separated coal and gangue;

[0024] Step S41, the image acquisition device acquires the images of the coal and gangue on the gangue belt conveyor and the coal belt conveyor;

[0025] Step S42, the images are transmitted to the server for pretreatment, including gray scale, smoothing and sharpening processing of the images, to obtain the pretreated images;

[0026] Step S43, using the image processing module of the MATLAB library in the server, based on the pre-processed image, using the gray level co-occurrence matrix, extracting the contrast, angular second moment feature parameters, using the gray information, extracting the gray mean and gray variance feature parameters; the output texture and gray feature are fused to form the contrast, angular second moment, gray mean, gray variance feature as the feature vector data set;

[0027] Step S44, the feature vector data set is input as the input, and the actual coal and gangue real label is output as the output, and is input into the Relief-MRMR-SVM model, and the model is trained, and the weight parameters of the Relief-MRMR-SVM model are obtained, and the weight parameters of the Relief-MRMR-SVM model are embedded in the server;

[0028] Step S45, the coal and gangue images newly collected by the image acquisition device are transmitted to the server for processing and feature extraction, and then the trained Relief-MRMR-SVM model is used for classifying the extracted features;

[0029] Step S46, the server receives the identification result of coal and gangue, and transmits the classification information to the DeltaV distributed control system, and the DeltaV distributed control system controls the mechanical arm to optimize the separation of coal and gangue according to the classification information and instructions.

[0030] Therefore, the application adopts the above-mentioned coal and gangue separation system and method based on multi-stage screening and inclined separation, and has the following beneficial technical effects:

[0031] (1) The coal and gangue are finely classified according to the particle size range by the coal and gangue particle size multi-stage screening sub-system, combined with the preliminary separation of the inclined coal and gangue separation sub-system and the deep optimization separation of the high-precision coal and gangue identification separation sub-system, so that the intelligent and accurate separation of coal and gangue is realized.

[0032] (2) The system and method improve the efficiency and quality of coal separation, effectively reduce the energy consumption and labor cost in the separation process, and have important significance for the rational use of coal resources and environmental protection. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 It is a structure schematic view of the first embodiment of the coal and gangue separation system based on multi-stage screening and inclined separation of the application;

[0034] Figure 2 It is a multi-stage roller shaft screen structure schematic view of the first embodiment of the coal and gangue separation system based on multi-stage screening and inclined separation of the application;

[0035] Figure 3This is a schematic diagram of the information transmission process in an embodiment of the coal and gangue separation system based on multi-stage screening and inclined plane separation according to the present invention.

[0036] Figure 4 This is a schematic flowchart of a second embodiment of the coal and gangue separation method based on multi-stage screening and inclined plane separation of the present invention;

[0037] Figure 5 This is a force analysis diagram of coal or gangue on an inclined belt conveyor according to Embodiment 2 of the present invention.

[0038] Figure Labels

[0039] 1. Main belt conveyor; 2. Gangue; 3. Coal; 4. Secondary belt conveyor; 5. Roller screen; 6. Inclined chute; 7. Steel plate frame; 8. Descending belt conveyor; 9. Inclined belt conveyor; 10. Servo motor; 11. Force sensor; 12. Gangue conveyor belt conveyor; 13. Coal conveyor belt conveyor; 14. Robotic arm; 15. Image acquisition equipment; 16. Programmable logic controller; 17. Server; 18. DeltaV distributed control system. Detailed Implementation

[0040] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0041] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0042] Example 1

[0043] like Figure 1 The diagram shown is a structural schematic of a coal and gangue separation system based on multi-stage screening and inclined plane separation according to the present invention, comprising:

[0044] A multi-stage molecular sieve system for coal gangue particle size is used to classify coal 3 and gangue 2 according to particle size.

[0045] The multi-stage screening molecular system for coal gangue particle size includes n screening units arranged in a stepped manner from top to bottom on a steel plate frame 7 (in this embodiment, n is set to 4).

[0046] The four screening units are a primary screening unit, a secondary screening unit, a tertiary screening unit, and a quaternary screening unit. Each of the primary, secondary, and tertiary screening units includes one auxiliary belt conveyor 4 and one roller screen 5, with the roller screen 5 mounted on the auxiliary belt conveyor 4. The quaternary screening unit includes one auxiliary belt conveyor 4. Any two adjacent auxiliary belt conveyors 4 are connected by an inclined chute 6. The ends of all four screening units are connected to an inclined plane coal and gangue separation subsystem. The primary screening unit is also connected to the main belt conveyor 1.

[0047] In this embodiment, one roller screen 5 consists of three rollers.

[0048] like Figure 2 As shown, the main belt conveyor 1 transports gangue 2 and coal 3 to a multi-stage screening system for coal gangue particle size set up by a certain mine. Coal 3 and gangue 2 fall into the first-stage screening unit. According to the actual sorting requirements of the mine, the roller spacing of the roller screen 5 on the first-stage screening unit is adjusted to 60mm. Coal 3 and gangue 2 with a particle size greater than 60mm will continue to be transported along the auxiliary belt conveyor 4 to the inclined coal gangue sorting subsystem for the next step of sorting. Coal 3 and gangue 2 with a particle size less than 60mm will fall to the second-stage screening unit through the roller spacing.

[0049] Similarly, the screening processes in the secondary and tertiary screening units are similar to those in the primary screening unit. In the secondary screening unit, the roller spacing of the roller screen 5 is adjusted to 40mm. Coal 3 and gangue 2 with a particle size greater than 40mm will continue to be conveyed along the auxiliary belt conveyor 4 to the inclined coal and gangue separation subsystem, while coal 3 and gangue 2 with a particle size less than 40mm will fall into the tertiary screening unit. In the tertiary screening unit, the roller spacing of the roller screen 5 is adjusted to 20mm. Coal 3 and gangue 2 with a particle size greater than 20mm will continue to be conveyed along the auxiliary belt conveyor 4 to the inclined coal and gangue separation subsystem, while coal 3 and gangue 2 with a particle size less than 20mm will fall into the quaternary screening unit.

[0050] After multi-stage screening, coal 3 and gangue 2 are separated into four ranges according to particle size: greater than 60mm, 40-60mm, 20-40mm, and 0-20mm. Each type of coal 3 and gangue 2 enters its corresponding inclined plane coal and gangue separation subsystem for subsequent sorting and processing.

[0051] Inclined coal and gangue separation subsystem is used to initially separate coal 3 and gangue 2.

[0052] The inclined coal and gangue sorting subsystem includes four descending belt conveyors 8, four inclined belt conveyors 9, and one programmable logic controller 16 (PLC).

[0053] Each inclined belt conveyor 9 is driven by a servo motor 10 and equipped with a force sensor 11. The head end of the descending belt conveyor 8 is connected to the end of each screening unit.

[0054] The inclined belt conveyor 9 can better separate coal 3 and gangue 2 with similar particle size ranges. Coal 3 and gangue 2 with the same particle size range are similar in morphology, so the difference in their physical properties on the inclined belt conveyor 9 can be used to separate them more effectively, reducing the influence of volume and other irrelevant factors. At the same time, it is convenient to meet the specific needs of coal mines for the particle size range of coal 3 and gangue 2, which is beneficial to the subsequent processing of coal 3 and gangue 2.

[0055] A high-precision coal and gangue identification and sorting subsystem is used for fine sorting of the initially separated coal 3 and gangue 2.

[0056] The high-precision coal gangue identification and sorting subsystem includes four gangue conveyor belts 12, four coal conveyor belts 13, one server 17, and one DeltaV distributed control system 18, as well as eight robotic arms 14 and eight image acquisition devices 15 set on both sides of the gangue conveyor belts 12 and the coal conveyor belts 13.

[0057] The gangue conveyor belt 12 and the coal conveyor belt 13 are arranged in front of the inclined belt conveyor 9 in sequence.

[0058] In this embodiment, the mine employs a pseudo dual-energy X-ray transmission image acquisition device—a portable dual-energy X-ray flat panel detector—to acquire clear images of coal 3 and gangue 2, respectively. During image acquisition, the device not only utilizes its high-precision dual-energy X-ray technology but also ensures accuracy and efficiency through intelligent operation. Furthermore, to further enhance the level of automation, the mine is also equipped with a robotic arm 14, which works in conjunction with the image acquisition device 15 to complete the entire process from sample placement to image acquisition.

[0059] like Figure 3 As shown, the programmable logic controller 16 is used to receive and process the data of the inclined belt conveyor 9 collected by the force sensor 11, and then transmit the processing result to the servo motor 10. The servo motor 10 drives the inclined belt conveyor 9 to adjust the inclination angle and speed of the inclined belt conveyor 9.

[0060] Server 17 is used to collect and process image information from image acquisition device 15, run recognition algorithms to accurately identify coal 3 and gangue 2, and then transmit the processing results to DeltaV distributed control system 18. DeltaV distributed control system 18 is used to control parallel SCARA robotic arm 14 to complete the deep optimization sorting of coal 3 and gangue 2 based on the recognition results of server 17.

[0061] Example 2

[0062] like Figure 4As shown, based on the sorting system of example one, this example provides a coal and gangue sorting method based on multi-stage screening and inclined separation, including the following steps:

[0063] Step S1, commissioning phase, adjust and determine the related equipment and parameters of each subsystem.

[0064] Step S11, adjust the roller spacing of the roller screen 5 in the first-stage screening unit, the second-stage screening unit and the third-stage screening unit in the multi-stage screening subsystem of coal and gangue particle size, which are 60mm, 40mm and 20mm respectively, and divide the screened coal 3 and gangue 2 into four levels according to particle size, i.e. extra-large particle size, large particle size, medium particle size and small particle size.

[0065] Step S12, in order to ensure that the coal 3 and gangue 2 can make accelerated motion along the slope upward on the inclined belt conveyor 9, and realize the maximum difference in horizontal displacement after the coal 3 and gangue 2 are thrown out, the inclination angle θ of the inclined belt conveyor 9 needs to be determined.

[0066] As shown, Figure 5 For force analysis of the coal 3 and gangue 2, we can get:

[0067] G=mg;

[0068] f=μ×F N ;

[0069] F N =G×cosθ;

[0070] f-G×sinθ=ma;

[0071] Where G represents the gravity of the coal 3 or gangue 2 on the inclined belt conveyor 9, m represents the mass of the coal 3 or gangue 2, g represents the acceleration of gravity, f represents the friction of the coal 3 or gangue 2 on the inclined belt conveyor 9, a represents the acceleration of the coal 3 or gangue 2 on the inclined belt conveyor 9, and μ represents the friction coefficient of the coal 3 or gangue 2 on the inclined belt conveyor 9.

[0072] In order for the coal 3 or gangue 2 to make accelerated motion along the slope upward on the inclined belt conveyor 9, the following relationship needs to be met: the force of the coal 3 or gangue 2 along the inclined belt conveyor 9 upward needs to be greater than the force downward, i.e. it is required that:

[0073] f>G×sinθ;

[0074] Therefore we can get:

[0075] μ>tanθ;

[0076] The friction coefficient value of the coal 3 on the inclined belt conveyor 9 is 0.5, and the friction coefficient value of the gangue 2 on the inclined belt conveyor 9 is 0.4.

[0077] The inclination angle θ of the inclined belt conveyor 9 is calculated as follows:

[0078] 0 < θ < min{arctan μ1, arctan μ2};

[0079] Wherein, μ1 represents the friction coefficient of the coal 3 on the inclined belt conveyor 9, and the value is 0.5; μ2 represents the friction coefficient of the gangue 2 on the inclined belt conveyor 9, and the value is 0.4.

[0080] The four inclined belt conveyors 9 are respectively arranged at the right lower side of each auxiliary belt conveyor 4 at a horizontal distance of 3.00 m, and the coal 3 and the gangue 2 are transferred to the four inclined belt conveyors 9 through the 5.00 m descending belt conveyor 8.

[0081] Through the trial operation, the related parameters are adjusted, the force sensor 11 monitors the data of the inclined belt conveyor 9 in real time, and the data is transmitted to the editable logic controller 16. The editable logic controller 16 calculates according to the above principle, and then obtains the accurate optimal inclination angle of the inclined belt conveyor 9. The inclination angle θ of the four inclined belt conveyors 9 is <arctan(0.4) = 21.8°, and the inclination angle θ of the four inclined belt conveyors 9 is 21°.

[0082] Step S13, determining the running speed V1 of the inclined belt conveyor 9:

[0083] In order to realize the speed difference of the coal 3 and the gangue 2 on the inclined belt conveyor 9 and enhance the separation effect, the running speed V1 of the inclined belt conveyor 9 is determined. If the coal 3 and the gangue 2 reach the same speed as the inclined belt conveyor 9 before reaching the tail end of the inclined belt conveyor 9, the initial speed of the two inclined throwing motions will be the same, and then the coal 3 and the gangue 2 cannot be effectively separated. Therefore, the formula is as follows:

[0084] V1 > V2, V1 > V3;

[0085] Wherein, V2 represents the speed required for the coal 3 to separate from the inclined belt conveyor 9, and V3 represents the speed required for the gangue 2 to separate from the inclined belt conveyor 9.

[0086] According to the formula:

[0087] a1 = μ1gcosθ - g sinθ;

[0088] a2 = μ2gcosθ - g sinθ;

[0089] Wherein, a1 represents the acceleration of coal 3 on the inclined belt conveyor 9, and a2 represents the acceleration of gangue 2 on the inclined belt conveyor 9.

[0090] The servo motor 10 receives the speed requirement and the inclination angle requirement, and adjusts the speed of the inclined belt conveyor 9.

[0091] The accelerations of the coal 3 and the gangue 2 on the inclined belt conveyor 9 can be calculated as 1.08 m / s 2 and 0.16 m / s 2 respectively, so the initial speeds of the coal 3 and the gangue 2 off the inclined belt conveyor 9 are V2=4.76 m / s and V3=2.01 m / s respectively, which are less than the running speed V1 of the inclined belt conveyor 9, so it can be ensured that the coal 3 and the gangue 2 can always accelerate on the inclined belt conveyor 9 until they fall off, so the running speed V1 of the four inclined belt conveyors 9 in the mine is set to 5 m / s.

[0092] The optimal inclination angle and the optimal speed are transmitted to the programmable logic controller 16, which adjusts the inclination angle of the inclined belt conveyor 9 by controlling the servo motor 10 to match the optimal inclination angle, and adjusts the speed of the inclined belt conveyor 9 to match the optimal speed.

[0093] Step S14, determine the length S of the inclined belt conveyor 9:

[0094] In order to avoid the coal 3 and the gangue 2 reaching the end of the inclined belt conveyor 9 before being equal to the speed of the inclined belt conveyor 9, the coal 3 and the gangue 2 cannot be sorted, so the length S of the inclined belt conveyor 9 needs to be determined:

[0095]

[0096] Wherein, V0 represents the speed of the coal and the gangue when they reach the beginning of the inclined belt conveyor 9.

[0097] Through the above calculation, the length of the inclined belt conveyor 9 can be determined as 10 m.

[0098] Step S15, determine the positions of the gangue conveying belt conveyor 12 and the coal conveying belt conveyor 13:

[0099]

[0100] Wherein, L1 represents the distance between the gangue conveying belt conveyor 12 and the inclined belt conveyor 9, and L2 represents the distance between the coal conveying belt conveyor 13 and the inclined belt conveyor 9.

[0101] The distance d between the coal belt conveyor 13 and the gangue belt conveyor 12:

[0102] d = L1-L2;

[0103] After derivation, it can be obtained that:

[0104] d = 4sinθcos 2 θ(μ1-μ2)S;

[0105] The distance d between the coal 3 and the gangue 2 is affected by the inclination angle θ of the inclined belt conveyor 9, the length S, and the friction coefficients of the coal 3 and the gangue 2. Under the condition that θ, μ1 and μ2 are constant, increasing S can increase the distance between the coal 3 and the gangue 2, so as to achieve better separation effect.

[0106] The inclination angle θ of the inclined belt conveyor 9 that meets the actual separation requirements of the mine is 21°, and it is known that μ1 = 0.5, μ2 = 0.4, and S = 10 m. Therefore, the calculation can obtain that the distance L1 between the gangue belt conveyor 12 and the inclined belt conveyor 9 is 0.27 m, the distance L2 between the coal belt conveyor 13 and the inclined belt conveyor 9 is 1.52 m, and thus the distance d between the coal belt conveyor 13 and the gangue belt conveyor 12 is 1.25 m, which can achieve the effect of separating the coal belt conveyor 13 and the gangue belt conveyor 12.

[0107] Step S2, the system is formally operated, and the multi-level coal and gangue particle size screening subsystem is used to complete the screening of coal 3 and gangue 2 with different particle sizes.

[0108] Step S21, the main belt conveyor 1 conveys the coal 3 and the gangue 2 to the first screening unit of the multi-level coal and gangue particle size screening subsystem.

[0109] Step S22, the coal 3 and the gangue 2 fall from the main belt conveyor 1 to the first screening unit, and when passing through the roller screen 5 on the first screening unit, the coal 3 and the gangue 2 larger than 60 mm will pass through the roller screen 5 and enter the descending belt conveyor 8, and then be sent to the inclined belt conveyor 9. The coal 3 and the gangue 2 smaller than 60 mm will fall into the second screening unit, and then be screened for the second time by the roller screen 5 on the second screening unit. The coal 3 and the gangue 2 smaller than 40 mm fall into the third screening unit and are screened again. Finally, the coal 3 and the gangue 2 are divided into four parts, i.e., large particle size larger than 60 mm, large particle size larger than 40 mm and smaller than 60 mm, medium particle size larger than 20 mm and smaller than 40 mm, and small particle size smaller than 20 mm, completing the multi-level screening of the coal 3 and the gangue 2, and then being conveyed to the corresponding four inclined belt conveyors 9.

[0110] Step S3, the inclined coal and gangue separation subsystem preliminarily separates the coal 3 and the gangue 2 with the same particle size range.

[0111] Step S31, each particle size of coal 3 and gangue 2 screened out through step S22 is transferred to the corresponding inclined belt conveyor 9 through the descending belt conveyor 8;

[0112] Step S32, coal 3 and gangue 2 are conveyed to the bottom of the corresponding inclined belt conveyor 9 at a speed of V0, and start to move in the direction of the slope at an accelerated speed;

[0113] Step S33, due to the difference in physical properties of different particle sizes of coal 3 and gangue 2, the coal 3 and gangue 2 leave the inclined belt conveyor 9 at different initial speeds through the speed, length and inclination angle set by each inclined belt conveyor 9, and respectively fall into the coal conveying belt conveyor 13 which is 1.52 m away from the inclined belt conveyor 9 and the gangue conveying belt conveyor 12 which is 0.27 m away from the inclined belt conveyor 9.

[0114] Step S4, the high-precision coal and gangue recognition and separation subsystem implements deep optimization separation on the preliminarily separated coal 3 and gangue 2;

[0115] Step S41, the image acquisition device 15 acquires 2000 images of coal 3 and gangue 2 on the gangue conveying belt conveyor 12 and the coal conveying belt conveyor 13;

[0116] Step S42, the images are transmitted to the server 17 for preprocessing, including grayscale, smoothing and sharpening processing of the images, to obtain preprocessed images;

[0117] Step S43, using the image processing module of the MATLAB library in the server 17, based on the preprocessed images, using the gray level co-occurrence matrix, extracting the contrast and angular second moment feature parameters, using the gray level information, extracting the gray level mean and gray level variance feature parameters; fusing the output texture and gray level features to form the contrast, angular second moment, gray level mean and gray level variance features as the feature vector data set;

[0118] Using the gray level co-occurrence matrix, the contrast and angular second moment feature parameters are extracted, and the calculation is as follows:

[0119]

[0120] Wherein, N represents the contrast, E represents the angular second moment, P(i,j,d,q) represents the gray level co-occurrence matrix, i and j respectively represent the gray level values of two pixel points, d and q respectively represent the distance and orientation of two pixel points;

[0121] Based on the gray level information, the gray level mean and gray level variance are extracted, and the calculation is as follows:

[0122]

[0123] wherein m represents the mean value of the gray scale, L represents the number of gray scale, z i represents the discrete random variable of the image gray scale, P(z i ) represents the probability distribution estimation value; then the center distance s n and the gray scale variance σ 2 are calculated:

[0124] s n (z) = (z i -m) n P(z i );

[0125] σ 2 = s2(z);

[0126] wherein n represents the order of the moment; s2(z) represents the center distance with the order of 2.

[0127] Tables 1-4 show the characteristic parameters of 5 images of coal 3 and gangue 2 processed by the MATLAB library image processing module.

[0128] Table 1 Gray scale characteristic parameters of coal

[0129]

[0130] Table 2 Gray scale characteristic parameters of gangue

[0131]

[0132] Table 3 Texture characteristic parameters of coal

[0133]

[0134]

[0135] Table 4 Texture characteristic parameters of gangue

[0136]

[0137] Table 5 Construction table of related characteristic data set of coal and gangue (part)

[0138]

[0139] Step S44, input the characteristic vector data set (Table 5) as input and the actual coal 3 and gangue 2 true label as output into the Relief-MRMR-SVM model, train the model, obtain the weight parameters of the Relief-MRMR-SVM model, and embed the weight parameters of the Relief-MRMR-SVM model into the server;

[0140] The specific process of training the Relief-MRMR-SVM model is as follows:

[0141] In order to construct the recognition model of coal 3 and gangue 2, the gray feature and the texture feature are first fused to form a data set containing 2000 groups of data. The data set includes four input features: gray mean, gray variance, contrast and angular second moment, and an output label, that is, the actual coal 3 or gangue 2 classification. In this data set, 80% of the data is used as the training set, and the remaining 20% is used as the verification set. Next, the feature vector composed of contrast, angular second moment, gray mean and gray variance is input into the Relief-MRMR-SVM model as the input feature for the recognition of coal 3 and gangue 2. In the training stage, 80% of the data in the training set is used to train the Relief-MRMR-SVM model to learn the mapping relationship from features to labels. After training, the remaining 20% of the verification set data is used to verify the model, and the performance of the model is evaluated by comparing the recognition results of the model with the true labels of the verification set. When the correct samples of the verification set are highly consistent with the recognition results of the model, it is considered that the model has learned effective weight parameters and can be used for accurate recognition of coal 3 and gangue 2.

[0142] Step S45, the newly collected coal 3 and gangue 2 images of the image acquisition device 15 are transmitted to the server 17 for processing and feature extraction, and then the trained Relief-MRMR-SVM model is used for classification of the extracted features;

[0143] Step S46, the server 17 receives the recognition results of coal 3 and gangue 2, and transmits the classification information to the DeltaV distributed control system 18, and the DeltaV distributed control system 18 controls the mechanical arm 14 to finely sort coal 3 and gangue 2 according to the classification information and instructions.

[0144] The test results show that the gangue picking rate of the coal conveying belt conveyor 13 and the coal picking rate of the gangue conveying belt conveyor 12 are both more than 90% on average, and the mispicking rate is less than 5%, which meets the specified requirements of high-precision coal-gangue separation.

[0145] It is worth noting that the contents not elaborated in the present application are all prior art and are well known to those skilled in the art.

[0146] Therefore, the present application adopts the above-mentioned multi-stage screening and inclined separation type coal-gangue separation system and method, which realizes intelligent and accurate separation of coal and gangue through the cooperation of multi-stage screening, inclined separation technology, high-precision coal-gangue recognition model and mechanical arm, and improves the efficiency and quality of separation.

[0147] It should be pointed out finally that the above examples are only used to illustrate the technical solutions of the present application but not to limit it, and although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can still be modified or replaced equivalently, and these modifications or equivalent replacements should not make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A coal and gangue separation system based on multi-stage screening and inclined surface separation, characterized in that, The application relates to a coal-gangue separating system based on multi-stage screening and slope separation. A multi-stage screening system for coal gangue particle size distribution includes one main belt conveyor, one steel plate frame, and... There are several screening units; among them... The screening units are arranged in a stepped manner on the steel plate frame. The end of each screening unit is connected to the inclined plane coal and gangue separation subsystem. Any two adjacent screening units are connected by inclined chute. Each screening unit is equipped with an auxiliary belt conveyor. Each auxiliary belt conveyor is equipped with a roller screen, and from the first auxiliary belt conveyor to... The roller spacing on the auxiliary belt conveyor decreases sequentially. The first screening unit is connected to the main belt conveyor, and the roller spacing is adjustable. A coal gangue sorting subsystem comprises a descending belt conveyor, a descending belt conveyor, a sloping belt conveyor and a programmable logic controller; the end of the descending belt conveyor is connected with the head of the sloping belt conveyor, each sloping belt conveyor is driven by a servo motor and is provided with a force sensor, and the head of each descending belt conveyor is connected with the end of a secondary belt conveyor; the programmable logic controller is used for accepting and processing data of the sloping belt conveyor collected by the force sensor, and then transmitting the processing result to the servo motor, so that the servo motor drives the sloping belt conveyor to adjust the inclination angle and speed of the sloping belt conveyor. A high-precision coal and gangue recognition and separation subsystem comprises a gangue belt conveyor, a coal belt conveyor, a server and a DeltaV distributed control system; wherein, the gangue belt conveyor and the coal belt conveyor are arranged along a conveying direction of the gangue belt conveyor and the coal belt conveyor respectively, and an image acquisition device and a mechanical arm are arranged on one side of each of the gangue belt conveyor and the coal belt conveyor; the server is used to collect and process image information of the image acquisition device, run a recognition algorithm to recognize coal and gangue, and then transmit the processing result to the DeltaV distributed control system; the DeltaV distributed control system is used to control the parallel SCARA type mechanical arms to complete deep optimization separation of coal and gangue according to the recognition result of the server.

2. A coal and gangue separation method based on multi-stage screening and inclined surface separation, characterized in that, The application relates to a coal-gangue separating system based on multi-stage screening and slope separation. Step S1, a trial operation stage, in which relevant devices and parameters of each subsystem are adjusted and determined; Step S11, adjusting the roller spacing of the roller screen on the first screening unit in the coal gangue particle multi-stage screening subsystem, and the roller spacing of the roller screen on the first screening unit is gradually reduced from the first auxiliary belt conveyor to the last auxiliary belt conveyor. the roller spacing of the roller screen on the first screening unit is gradually reduced from the first auxiliary belt conveyor to the last auxiliary belt conveyor.​ Step S12, determining the inclination angle of the inclined belt conveyor in the inclined coal and gangue separation subsystem : wherein, represents the friction coefficient of coal on the inclined belt conveyor, represents the friction coefficient of gangue on the inclined belt conveyor; Step S13, determining the speed of the inclined belt conveyor in the inclined coal and gangue separation subsystem : wherein, represents the speed of coal leaving the inclined belt conveyor, represents the speed of gangue leaving the inclined belt conveyor; Step S14, determining the length of the inclined belt conveyor in the inclined coal and gangue sorting subsystem S : wherein, denotes the acceleration of the coal moving on the inclined belt conveyor, denotes the acceleration of the gangue moving on the inclined belt conveyor, denotes the speed of the coal and gangue when reaching the head end of the inclined belt conveyor; Step S15, determining the position of the gangue conveying belt conveyor and the coal conveying belt conveyor in the high-precision coal and gangue recognition and separation subsystem: wherein, represents the distance between the gangue conveying belt conveyor and the inclined belt conveyor, represents the distance between the coal conveying belt conveyor and the inclined belt conveyor, represents the acceleration of gravity; Step S2, formal operation of the system, in which the coal-gangue particle size multi-stage screening subsystem is used to complete screening of coal and gangue with different particle sizes; Step S21, the main belt conveyor is used to convey the coal and gangue to the first screening unit of the coal-gangue particle size multi-stage screening subsystem; Step S22, when the coal and gangue pass through the roller screen on the first screening unit, the coal and gangue larger than the roller spacing pass through the roller screen, and then are transported into the inclined coal-gangue separation subsystem through the auxiliary belt conveyor. The coal and gangue smaller than the roller spacing pass through the roller spacing into the inclined channel and finally leak into the next screening unit, and then are screened by the next level of particle size, until the remaining coal and gangue fall into the first screening unit. Step S23, when the coal and gangue pass through the roller screen on the second screening unit, the coal and gangue larger than the roller spacing pass through the roller screen, and then are transported into the inclined coal-gangue separation subsystem through the auxiliary belt conveyor. The coal and gangue smaller than the roller spacing pass through the roller spacing into the inclined channel and finally leak into the next screening unit, and then are screened by the next level of particle size, until the remaining coal and gangue fall into the first screening unit. Step S24, when the coal and gangue pass through the roller screen on the third screening unit, the coal and gangue larger than the roller spacing pass through the roller screen, and then are transported into the inclined coal-gangue separation subsystem through the auxiliary belt conveyor. The coal and gangue smaller Step S3, the slope-type coal-gangue separating subsystem is used to preliminarily separate the coal and gangue with the same particle size range; Step S31, the coal and gangue with different particle sizes screened in step S22 are transferred to the corresponding slope-type belt conveyor through the descending belt conveyor; Step S32, coal and gangue are conveyed to the respective first end of the inclined belt conveyors at a speed of , and start to accelerate in the direction of the slope. Step S33, under the difference of physical properties of coal and gangue with different particle sizes, the coal and gangue leave the inclined belt conveyor to make inclined throwing motion with different initial speeds respectively through the speed, length and inclination angle of each inclined belt conveyor, and fall into the coal belt conveyor with a distance of from the inclined belt conveyor and the gangue belt conveyor with a distance of from the inclined belt conveyor respectively. Step S4, the high-precision coal-gangue identifying and separating subsystem is used to implement deep optimization separation of the preliminarily separated coal and gangue; Step S41, the image acquisition device is used to acquire images of the coal and gangue on the gangue conveying belt conveyor and the coal conveying belt conveyor; Step S42, the images are transmitted to the server for pretreatment, including gray-scale processing, smoothing and sharpening of the images, so as to obtain the pretreated images; Step S43, the image processing module of the MATLAB library in the server is used to extract the contrast and angular second moment characteristic parameters based on the pretreated images by using the gray level co-occurrence matrix, and the gray mean and gray variance characteristic parameters are extracted by using the gray information; the output texture and gray characteristics are fused to form the contrast, angular second moment, gray mean and gray variance characteristics as the characteristic vector data set; Step S44, the characteristic vector data set is input, and the actual coal and gangue real labels are output, and then the input is input into the Relief-MRMR-SVM model, the model is trained, the weight parameters of the Relief-MRMR-SVM model are obtained, and the weight parameters of the Relief-MRMR-SVM model are embedded in the server; Step S45, the newly acquired coal and gangue images of the image acquisition device are transmitted to the server for processing and feature extraction, and then the trained Relief-MRMR-SVM model is used to classify the extracted features; Step S46, the server receives the coal and gangue identification results, transmits the classification information to the DeltaV distributed control system, and the DeltaV distributed control system controls the mechanical arm to perform deep optimization separation of the coal and gangue according to the classification information and instructions.

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