A method for identifying water coal based on multi-line lidar scanning

Abstract

The present invention relates to a method for identifying water in coal based on multi-line lidar scanning, including: collecting data; scanning the falling material; constructing a simulated coal pile; analyzing and judging the shape of the pile; judging the slope of the pile; analyzing the water content; and ending the detection. The present invention determines the position coordinates of the point cloud to identify the shape of the coal pile and then judge the water content in the coal, and uses the reflectivity of the laser to water in the coal and the previously recorded water content data of the coal to accurately determine the water content in the coal, providing a solution for water content measurement for the complete automation of the loading station.

Description

Technical Field

[0001] The invention relates to a water-coal identification method based on multi-line laser radar scanning, which is a detection method and a method for real-time online detection in the coal shipping process. Background Art

[0002] In the storage area of ​​the coal preparation plant, if the product coal is stored for a long time, the moisture in the stored coal will sink to the bottom of the warehouse, resulting in a high moisture content in the first coal transported and accumulated at the bottom of the warehouse. Excessive moisture content in the coal not only reduces product quality and affects economic benefits, but also, if the flowing water coal is not specially treated, the water coal rushing down from the coal unloading port will strongly impact the body of the carriage to be loaded, causing damage to the carriage. According to convention, the first 10 cars a day are operated by the loader to conduct trial loading operations with a small opening of the unloading gate, and observe with the naked eye whether there is water coal. If there is water coal, the material is discharged slowly to avoid impacting the carriage, and then the driver is notified to unload the water coal into the coal yard and reload it, until there is no water coal, and then the car is continuously loaded for transportation.

[0003] With the increasing demand for automated coal loading, how to judge the moisture content in the coal to determine whether it can be loaded is a problem that needs to be solved. Summary of the invention

[0004] In order to overcome the problems of the prior art, the present invention proposes a method for identifying water-coal based on multi-line laser radar scanning. The method uses the reflection of laser by water to replace manual judgment of the water content in coal, thus realizing the automation of water-coal judgment.

[0005] The object of the present invention is achieved as follows: a method for identifying water coal based on multi-line laser radar scanning, the system used in the method includes: at least one multi-line laser radar installed above and behind the coal material discharge port of the product bin of the loading workshop for scanning the pile shape of the coal material below the discharge port, and an information analysis device with a database, the information analysis device is connected to the upper computer of the product bin, and the steps of the method are as follows:

[0006] Step 1, data collection: obtain various information of the coal currently loaded, including the normal fluidity of the coal currently loaded, the normal stockpile slope, and the reflectivity of different water contents;

[0007] Step 2: Scan the coal-bearing material: The coal-loading vehicle enters the unloading port of the loading room and opens the car to unload the coal. During the unloading process, the laser radar scans the unloading area below the unloading port in real time, and selects the laser point cloud data shot on the coal pile surface. The point cloud data includes the spatial coordinates and reflectivity information of each laser point;

[0008] Step 3: Build a simulated coal pile: Use the spatial coordinates of the point cloud data to build a simulated coal pile in the carriage in real time and monitor the changes of the coal pile;

[0009] Step 4, stockpile shape analysis and judgment: Judge the water content in the coal stockpile according to the shape of the coal stockpile: When the coal enters the carriage and quickly levels the bottom of the carriage and cannot be piled up, it is judged that the water content in the coal is very high; When the coal enters the carriage and is in a viscous state with poor fluidity, the pile surface is steep and irregular, then it is judged that the water content of the coal is relatively high; When the coal can form a pile with a stacking slope of 30-45° after entering the carriage, it is considered that the water content of the coal is close to or has reached the normal water content.

[0010] Step 5, stockpile slope judgment: Extract the stacking slope of the normal water content of the current coal and compare it with the currently measured stacking slope to judge whether the current coal meets the standard of normal water content.

[0011] Step 6, water content analysis: Use the laser point reflectivity in the point cloud data for data analysis and analogy to accurately determine the water content in the coal.

[0012] Step 7, end detection: Repeat steps 2-6, and appropriately adjust the unloading and transportation vehicles until it is determined that the coal discharged from the chute reaches the normal water content, and end the water coal detection.

[0013] Furthermore, the steps of the water content analysis include the following sub-steps:

[0014] Sub-step 1: Select the point cloud data of an area below the material dropping port and on the side opposite to the vehicle traveling direction.

[0015] Sub-step 2: Remove the data with too high and too low reflectivity, and calculate the average reflectivity data of the selected laser point cloud.

[0016] Sub-step 3: Use coals similar to the current coal with different moisture reflectivities for analogy to determine the water content in the current coal.

[0017] The advantages and beneficial effects of the present invention are: The present invention determines the position coordinates of the point cloud to identify the shape of the coal stockpile and then judge the water content in the coal, and uses the reflectivity of the laser to the water in the coal and the previously recorded coal moisture data to accurately determine the water content in the coal, providing a solution for moisture measurement for fully automated loading. Description of the Drawings

[0018] The present invention will be further described below with reference to the drawings and embodiments.

[0019] Figure 1 is the system structure schematic diagram used in the method of Embodiment 1 of the present invention;

[0020] Figure 2 is the flow chart of the method of Embodiment 1 of the present invention. DETAILED DESCRIPTION

[0021] Embodiment 1:

[0022] This embodiment is a method for identifying wet coal based on multi-line laser radar scanning. The wet coal identification system used in the method includes: at least one multi-line laser radar 4 installed above and behind the coal material discharge port 2 of the loading workshop product bin 1 for scanning the pile 3 of the coal material below the discharge port, and an information analysis device 5 with a database 501, the information analysis device is connected to the upper computer 6 of the product bin, such as Figure 1 shown.

[0023] The water-coal identification system described in this embodiment is mainly composed of a multi-line laser radar and an information analysis device. The multi-line laser radar can be a general device, with multiple laser lines covering the width of the carriage, and scanning in a straight line along the longitudinal direction (front and back) of the carriage to form a scan of the entire carriage 7 plane. Figure 1 The information analysis device is an electronic device with digital processing capabilities, which is used to analyze and judge the information obtained by the laser radar to identify water coal. The information analysis device can be a separate hardware device or software installed in the product warehouse master control system. The host computer is a product warehouse master control electronic device, which has a product warehouse master control system inside, and is used to control the blanking of the product warehouse. It is an electronic device with computing and storage functions such as an industrial PC.

[0024] The specific steps of the method described in this embodiment are as follows: Figure 2 As shown:

[0025] Step 1, data collection: obtain various information of the coal currently loaded, including the normal fluidity of the coal currently loaded, the normal stockpile slope, and the reflectivity of different water contents.

[0026] Normal coal also has a certain amount of water content. Its fluidity will be affected by the different water content, which will in turn affect the slope of the coal pile (the angle between the inclined surface and the horizontal surface formed when the coal is naturally piled up). At the same time, the particle size of various coals will also affect the fluidity of the coal, as well as the reflectivity of the current coal at different water contents. These data should be obtained before loading, or measured in advance, for comparison and judgment.

[0027] Step 2, scanning the falling materials: the coal-loading vehicle enters the unloading port of the loading room and opens the car to unload the materials. During the unloading process, the laser radar scans the falling material area below the unloading port in real time, and selects the laser point cloud data shot on the coal pile surface. The point cloud data includes the spatial coordinates and reflectivity information of each laser point.

[0028] The vehicle for loading coal is usually a truck (it can also be a railway carriage). The loading area is the position where a chute and a discharge opening are set below the storage bin, that is, the actual loading position. The lidar scans continuously from the rear of the vehicle to the front or vice versa for the coal material falling into the carriage. The point positions in the point cloud can be determined according to the requirements of detection accuracy and the amount of calculation.

[0029] Step 3, construct a simulated coal pile: Utilize the spatial coordinates of the point cloud data to establish a simulated coal pile in the carriage in real time and monitor the changes of the coal pile.

[0030] Since the lidar scans the carriage with multiple lines, the width and length scanned form a height difference on the plane, and a three-dimensional pile is formed based on this height difference. This pile shape is real-time and continuously changes as the amount of coal material falling into the carriage increases. The water content of the water coal can be judged by the formation of the coal pile.

[0031] Step 4, analyze and judge the pile shape: Judge the water content in the coal material according to the shape of the coal pile: When the coal material quickly flattens the bottom of the carriage after entering the carriage and cannot be piled up, it is judged that the water content in the coal material is very large; when the coal material is in a viscous state after entering the carriage, with poor fluidity, a steep and irregular pile surface, it is judged that the water content of the coal material is relatively large; when the coal material can form a pile with a stacking slope of 30 - 45 degrees after entering the carriage, it is considered that the water content of the coal material is close to or has reached the normal water content.

[0032] During the process of the coal material discharging downward, the coal material accumulates and slides to form a pile surface. The pile surface morphology is different for different water contents of the coal material, mainly including three types: a. Abnormal liquid coal material, in the form of a water-like fluid, with a very large water content and fast fluidity, which can quickly spread flat on the bottom of the carriage; b. Normal coal material, with good fluidity, in the form of a pile surface inclined at a certain angle, and this pile surface angle is related to the coal variety (density, particle size); c. Abnormal viscous coal material, in the form of jelly, with a relatively large water content and poor fluidity, and a steep and irregular pile surface. From the three coal material forms of a, b, and c, it is not difficult to draw the conclusion: Measuring the pile slope of the coal material below the discharge opening in real time can judge whether the coal material is water coal. The coal material with a pile slope in the range of about 30 - 45 degrees can be identified as normal coal, and the coal without a slope (spreading flat on the carriage) or with a slope close to a right angle and irregular is identified as water coal.

[0033] Step 5, judge the pile slope: Extract the stacking slope of the normal water content of the current coal material and compare it with the currently measured stacking slope to judge whether the current coal material meets the standard of normal water content;

[0034] The slope of the coal pile surface can be used to calculate the inclination angle of the coal pile surface based on the spatial coordinates (horizontal and height values) of each laser point on the coal pile surface. Select the multi-point data of the laser line that longitudinally cuts the coal pile surface, and perform linear fitting on the horizontal and height coordinate values of each point data using the least squares method to calculate the coal pile surface curve y = bx + a. When the coal pile slope (slope) b is close to 30 - 45 degrees, it indicates normal material, and when it is close to 0 degrees or 90 degrees, it indicates that the coal is water coal. After a relatively complete coal pile is formed, the measured and calculated stacking slope should be compared with the normal stacking slope of the current coal to determine whether the moisture content of the coal being loaded has reached the normal standard.

[0035] Step 6, moisture content analysis: Use the laser point reflectivity in the point cloud data for data analysis and analogy to accurately determine the moisture content in the coal.

[0036] Perform data analysis on the laser point cloud reflectivity of the coal pile surface: Since the coal is black in color, has good light absorption, and a low reflectivity, when the coal contains more moisture, its reflectivity increases accordingly. Therefore, it is not difficult to determine the moisture content of water coal by comparing the laser point reflectivity in the point cloud data.

[0037] Step 7, end detection: Repeat steps 2 - 6, and appropriately adjust the unloading and transportation vehicles until it is determined that the coal discharged from the chute has reached the normal moisture content, and then end the water coal detection.

[0038] During the process of the chute discharging coal, the lidar continuously scans the coal entering the carriage, continuously conducts detection, and timely notifies the product warehouse total control system to transport and process the coal with more moisture, and then continue to discharge coal until the moisture content in the coal meets the requirements and the detection ends.

[0039] Embodiment 2:

[0040] This embodiment is an improvement of Embodiment 1 and a refinement of Embodiment 1 regarding moisture content analysis. The steps of the moisture content analysis include the following sub-steps:

[0041] Sub-step 1: Select the point cloud data of an area below the material discharge port and on the side opposite to the vehicle traveling direction.

[0042] Analysis using the reflectivity data in the point cloud data can use only a part of the data. In this embodiment, an area on the side opposite to the vehicle traveling direction ( Figure 1 area A in the figure) is selected as the research object, and the reflectivity data of this area is calculated.

[0043] Sub-step 2: Remove the too high and too low reflectivity data, and calculate the average reflectivity data of the selected laser point cloud.

[0044] For example: Select 300 reflectivity data points, remove the 100 points with relatively high reflectivity and the 100 points with relatively low reflectivity, and only perform an average calculation on the 100 points in the middle value range to obtain the reflectivity of the coal material.

[0045] Sub-step 3: Use the reflectivity of coal materials similar to the current coal material at different moisture contents for analogy to determine the moisture content in the current coal material.

[0046] For various coal materials, the emissivity under different moisture content states should be recorded in advance and stored in the database as scale data. During actual measurement, the reflectivity of the coal material being loaded and lowered in real time is detected and compared with the scale data to quantify the moisture content of the coal material and determine the moisture amount in the coal material.

[0047] By using the detection of the magnitude of the reflectivity of the coal material, it is possible to effectively judge the moisture content of the coal material during pre-discharging, thereby adjusting the size of the discharge port and avoiding the impact damage of the water-containing coal material on the carriage.

[0048] Finally, it should be noted that the above is only used to illustrate the technical solution of the present invention and not to limit it. Although the present invention has been described in detail with reference to the preferred arrangement, those of ordinary skill in the art should understand that the technical solution of the present invention (such as the type or form of the loading station, the form of the lidar and the information analysis device, the sequence of steps, etc.) can be modified or equivalently replaced without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for identifying water coal based on multi-line lidar scanning, and the system used in the method includes: At least one multi-line lidar installed above the rear of the coal discharge opening of the product bin in the loading workshop for scanning the stacking form of the coal material below the discharge opening, and an information analysis device with a database, the information analysis device is connected to the upper computer of the product bin, and it is characterized in that the steps of the method are as follows: Step 1, collect data: Obtain various information of the current coal material for loading, including the normal fluidity, normal stacking slope, and reflectivity of different water contents of the current coal material for loading; Step 2, scan the falling material: When the coal loading vehicle enters the discharge opening of the loading workshop and starts to discharge materials into the carriage, during the discharging process, the lidar scans the falling material area below the discharge opening in real time, and selects the laser point cloud data projected on the coal material heap surface. The point cloud data includes the spatial coordinates and reflectivity information of each laser point; Step 3, construct a simulated coal material heap: Use the spatial coordinates of the point cloud data to establish a simulated coal material heap in the carriage in real time and monitor the changes of the coal material heap; Step 4, analyze and judge the shape of the material heap: Judge the water content in the coal material according to the shape of the coal material heap: When the coal material quickly levels the bottom of the carriage after entering the carriage and cannot be stacked, it is judged that the water content in the coal material is very high; When the coal material is in a viscous state after entering the carriage, with poor fluidity, a steep and irregular heap surface, it is judged that the water content of the coal material is relatively high; When the coal material can form a pile with a stacking slope of 30-45 after entering the carriage, it is considered that the water content of the coal material is close to or has reached the normal water content; Step 5, judge the stacking slope: Extract the stacking slope of the normal water content of the current coal material and compare it with the currently measured stacking slope to judge whether the current coal material meets the standard of normal water content; Step 6, water content analysis: Use the reflectivity of the laser points in the point cloud data for data analysis and analogy to accurately determine the water content in the coal material; Step 7, end the detection: Repeat steps 2-6, and appropriately adjust the discharging and transportation vehicles until it is determined that the coal material discharged from the chute reaches the normal water content, and end the detection of water coal; 2. The method according to claim 1, wherein The steps of the water content analysis include the following sub-steps: Sub-step 1: Select the point cloud data of an area below the falling material opening and on the side opposite to the direction of vehicle travel; Sub-step 2: Remove the data of too high and too low reflectivity, and calculate the average reflectivity data of the selected laser point cloud; Sub-step 3: Use the reflectivity of coal materials similar to the current coal material with different water contents for analogy to determine the water content in the current coal material.

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