Conveyance amount calculation method

Abstract

To enable low-cost and highly accurate calculation of a conveyance amount of a conveyance object converted by a belt conveyor.SOLUTION: A conveyance amount calculation device 100 comprises a conveyance amount calculation unit 113 that calculates a cross-sectional area of a conveyance object on the basis of belt point cloud data indicating a shape of a belt of a belt conveyor that conveys the conveyance object, conveyance object point cloud data indicating the shape of the conveyance object, and calculates a volumetric conveyance amount of the conveyance object on the basis of the cross-sectional area and a belt speed of the belt conveyor. The conveyance amount calculation device 100 further comprises a detection unit that calculates a position of the belt on the basis of point cloud data indicating end points of the belt included in the conveyance object point cloud data, and the conveyance amount calculation unit 113 may calculate the belt point cloud data on the basis of the position of the belt.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a transport amount calculation method for measuring the transport amount of an object transported by a belt conveyor. [Background technology]

[0002] A volume measurement system described in Patent Document 1 is a technology for measuring the volume of transported objects (transported objects) such as soil, sand, gravel, and aggregates transported by a belt conveyor. The volume measurement system is a volume measurement system for measuring the volume of the transported objects flowing on the belt conveyor, and includes at least a line laser that irradiates the transported object with laser light from above, a digital camera that captures an image of the contour line of the transported object drawn by the irradiation of the laser light from an angle different from the irradiation direction of the line laser, a movement amount sensor that measures the movement amount of the belt conveyor, and an analysis device that calculates the volume of the transported object from the image data captured by the digital camera and the movement amount of the belt conveyor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-133478 A Summary of the Invention [Problem to be solved by the invention]

[0004] According to the volume measurement system described in Patent Document 1, it is possible to measure the volume with an accuracy according to the resolution of the digital camera. However, since a line laser and a digital camera are used as sensors, the cost is high, including the labor required for installation and adjustment. In addition, the contour line drawn on the transported object by the laser light is photographed by the digital camera, and the cross-sectional area of ​​the transported object is calculated by image analysis, which makes the processing complicated and costly. The present invention has been made in consideration of the above background, and has an object to provide a conveying amount calculation method that enables low-cost, highly accurate calculation of the conveying amount of an object conveyed by a belt conveyor. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, the conveying amount calculation method of the present invention includes a step in which a conveying amount calculation device calculates a cross-sectional area of ​​the conveyed object based on belt point cloud data indicating the shape of the belt of a conveyor belt that conveys the conveyed object and conveyed object point cloud data indicating the shape of the conveyed object, and a step in which a volumetric conveying amount of the conveyed object is calculated based on the cross-sectional area and the belt speed of the conveyor belt. Effect of the Invention

[0006] According to the present invention, it is possible to provide a method for calculating the amount of transport of an object transported by a belt conveyor at low cost and with high accuracy. Problems, configurations, and effects other than those described above will become apparent from the description of the following embodiments. [Brief description of the drawings]

[0007] [Figure 1] 1 is an overall configuration diagram of a transport amount calculation system according to an embodiment of the present invention. [Diagram 2] FIG. 13 is a diagram showing an output of a sensor when there is no article to be conveyed according to the embodiment. [Diagram 3] FIG. 13 is a diagram showing an output of a sensor when an object is present according to the embodiment. [Figure 4] 2 is a functional block diagram of a transport amount calculation device according to the embodiment. FIG. [Diagram 5] 5A to 5C are diagrams for explaining deviation of a belt according to the embodiment. [Figure 6] 4 is a diagram for explaining a cross-sectional area of ​​a transported object according to the embodiment; FIG. [Figure 7] 10 is a flowchart of a transport amount calculation process according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] A conveyance amount calculation device in a form (embodiment) for carrying out the present invention will be described below. Two-dimensional point cloud data acquired by a sensor installed on a belt conveyor is input to the conveyance amount calculation device. The sensor is, for example, LiDAR (Light Detection And Ranging or Laser Imaging Detection and Ranging), and can measure the distance to an object using laser light and acquire the (cross-sectional) shape of the conveyed object as two-dimensional point cloud data. The cross section is in the width direction (transverse section).

[0009] The conveying amount calculation device calculates the cross-sectional area of ​​the transported goods by calculating the difference with two-dimensional point cloud data that shows the shape of the belt when there is no transported goods, and then calculates the transport amount (volume) by multiplying it by the belt speed of the conveyor belt. The belt of a belt conveyor can be made of rubber, resin, metal, etc., but unlike roller conveyors, the belt can "deflect" and in some cases "shift left and right." This will be described later.

[0010] The belt of a belt conveyor may shift left and right (horizontally) relative to the direction of travel. The transport amount calculation device detects the belt's shift by detecting the belt's end points based on two-dimensional point cloud data, and corrects the two-dimensional point cloud data (point cloud data showing the belt's shape) when there is no transported object, thereby calculating point cloud data showing the shape of the shifted belt and acquiring the cross-sectional area. In this way, the transport amount calculation device can calculate the transport amount with high accuracy even if the belt is shifted.

[0011] <Overall configuration of the transport amount calculation system> 1 is an overall configuration diagram of a transport amount calculation system 10 according to this embodiment. The transport amount calculation system 10 includes a transport amount calculation device 100 and a sensor 200. In the following description, a three-dimensional coordinate system 380 is referred to. The Z axis is the traveling direction of a belt conveyor 300 (belt 310), the X axis is the horizontal (left-right) direction, and the Y axis is the up-down direction.

[0012] The sensor 200 is installed on the belt conveyor 300, measures the shape of the surface of the transported object seen from above by the belt conveyor 300, and outputs two-dimensional point cloud data, which is the measurement result, to the transport amount calculation device 100. The two-dimensional point cloud data indicates the shape of the surface of the transported object in an XY plane including the sensor 200 (a plane that is parallel to a plane including the X-axis and the Y-axis and includes the sensor 200).

[0013] The amount of deflection of the belt 310 increases according to the weight (transport amount) of the transported object. In this embodiment, the sensor 200 is installed on a portion (support portion 320 supporting the belt 310 from below) where the belt 310 does not deflect (the amount of deflection does not change) even if the weight increases, and two-dimensional point cloud data of the cross-sectional shape is acquired. Misalignment data is also acquired.

[0014] <2D point cloud data> 2 is a diagram showing an output of the sensor 200 when there is no transported object according to this embodiment. A dotted line 510 indicates a two-dimensional point cloud (two-dimensional point cloud data) corresponding to the surface of the belt 310. End points 511 and 512 of the dotted line 510 indicate the ends of the belt 310. 3 is a diagram showing the output of sensor 200 when an object is present according to this embodiment. Dotted line 520 indicates a two-dimensional point cloud corresponding to the surface of the object on belt 310. For ease of explanation, the position of each point in the two-dimensional point cloud is shown using a coordinate system with the lower left as the origin, the lower side as the X-axis, and the left side as the Y-axis. The X-axis and Y-axis correspond to the X-axis and Y-axis, respectively, of three-dimensional coordinate system 380 (see FIG. 1).

[0015] <Configuration of the transport amount calculation device> 4 is a functional block diagram of the transport amount calculation device 100 according to this embodiment. The transport amount calculation device 100 is a computer, and includes a control unit 110, a storage unit 120, and an input / output unit 180. User interface devices such as a display, keyboard, and mouse are connected to the input / output unit 180. The input / output unit 180 includes a communication device, and is capable of transmitting and receiving data to and from the sensor 200.

[0016] <<Transport amount calculation device: storage unit>> The storage unit 120 includes storage devices such as a read only memory (ROM), a random access memory (RAM), a solid state drive (SSD), etc. The storage unit 120 stores a measurement value database 130, a reference value 140, a transport amount database 150, and a program 128. The program 128 includes a description of a transport amount calculation process (see FIG. 7) to be described later.

[0017] The measurement value database 130 stores time series data of the two-dimensional point cloud data acquired from the sensor 200 in association with the acquisition time. The two-dimensional point cloud data is acquired, for example, at one-second intervals, and is a collection (coordinate group) of coordinates (XY coordinates) of points that indicate the shape of the surface of the transported object or the belt 310.

[0018] The reference value 140 is two-dimensional point cloud data (see FIG. 2) when there is no load, and is a coordinate group of points indicating the dotted line 510. As described later, the reference value 140 is (a coordinate group of) two-dimensional point cloud data indicating the surface of the belt 310 when the belt 310 is not misaligned left or right (in the X-axis direction). The transport amount database 150 is time-series data of the calculated transport amounts (transport amounts per unit time).

[0019] <<Transport amount calculation device: control unit>> The control unit 110 includes a CPU (Central Processing Unit), and is provided with a measurement unit 111, a detection unit 112, and a transport amount calculation unit 113. The measurement unit 111 stores the two-dimensional point cloud data, which is the output of the sensor 200, in the measurement value database .

[0020] <Control unit: Detection unit> The detector 112 detects deviation in the left-right direction (X-axis direction) with respect to the traveling direction (Z-axis direction) of the belt 310. Fig. 5 is a diagram for explaining deviation of the belt 310 according to this embodiment. The position in the X-axis direction of an end point 531 of a dotted line 530 indicating the surface of the belt 310 or the conveyed object is deviated from the position of the end point 511 at the reference value 140 (see Fig. 2).

[0021] Such a state occurs when belt 310 is misaligned in the positive direction of the X-axis. In such a state, the end of belt 310 on the negative side of the X-axis is detected as end point 531 of dotted line 530. Detection unit 112 detects such misalignment of belt 310 and calculates the amount of misalignment. The amount of misalignment can be calculated by comparing the X-coordinate of end point 531 with the X-coordinate of end point 511 at reference value 140.

[0022] As described above, the conveyance amount calculation device 100 includes the detection unit 112 that calculates the position of the belt 310 in the horizontal direction (X-axis direction) perpendicular to the traveling direction of the belt 310. The detection unit 112 calculates the position of the belt 310 in a horizontal direction (X-axis direction) perpendicular to the traveling direction of the belt 310 based on point cloud data (see end point 531) indicating the end point of the belt 310 included in the transported item point cloud data (see dotted line 530 in Figure 5).

[0023] <Control unit: Transport amount calculation unit> The conveyance amount calculation unit 113 calculates the cross-sectional area of ​​the conveyed object, and calculates the conveyance amount by multiplying it by the belt speed of the belt 310. Fig. 6 is a diagram for explaining the cross-sectional area of ​​the conveyed object according to this embodiment. A dotted line 540 indicates a two-dimensional point cloud corresponding to the surface of the conveyed object on the belt 310. Note that a left end point 541 of the dotted line 540 is shifted to the right (the positive side of the X-axis) compared to the X-coordinate of the end point 511 at the reference value 140.

[0024] Dotted line 550 is a two-dimensional point cloud obtained by shifting the two-dimensional point cloud indicated by reference value 140 (see dotted line 510) in the X-axis direction according to the position of belt 310 calculated by detection unit 112 based on dotted line 540. In other words, dotted line 550 indicates a two-dimensional point cloud corresponding to the surface of belt 310 in a state where there is no transported object when the two-dimensional point cloud indicated by dotted line 540 is acquired. Then, the area sandwiched between dotted lines 510 and 540 becomes the cross section of the transported object. Transport amount calculation unit 113 calculates the area of ​​this cross section and regards it as the cross section of the transported object.

[0025] As described above, the conveying amount calculation device 100 includes a conveying amount calculation unit 113 that calculates the cross-sectional area of ​​the conveyed object based on belt point cloud data (see dotted line 550) indicating the shape of the belt 310 of the belt conveyor 300 that conveys the conveyed object, and conveyed object point cloud data (see dotted line 540) indicating the shape of the conveyed object. The conveyance amount calculation unit 113 calculates the volume conveyance amount of the conveyed object based on the cross-sectional area and the belt speed of the belt conveyor 300.

[0026] The conveyance amount calculation unit 113 calculates belt point cloud data (see dotted line 550) based on the position of the belt 310. The conveyance amount calculation unit 113 calculates belt point cloud data (see dotted line 550) based on point cloud data indicating a preset belt shape (see reference value 140, dotted line 510) and the belt position calculated by the detection unit 112.

[0027] A method for calculating the cross-sectional area will be described below. The conveyance amount calculation unit 113 regards the dotted lines 510 and 540 as line graphs, calculates the area between the two line graphs, and sets the cross-sectional area as the area. Next, the conveyance amount calculation unit 113 multiplies the cross-sectional area by the belt speed of the belt 310 to calculate the conveyance amount per unit time at the time when the dotted line 540 is acquired. The belt speed can be acquired from the control device of the belt conveyor 300.

[0028] Alternatively, the conveyance amount calculation unit 113 may calculate the difference between the average values ​​of the heights (Y coordinate value) of the dotted lines 510, 540, and use this difference as the cross-sectional area by multiplying it by the width of the belt 310. The width of the belt 310 is the width of the dotted lines 510, 540 (the length in the X coordinate). The conveyance amount calculation unit 113 may calculate the weight conveyance amount by multiplying the conveyance amount by the specific gravity of the conveyed object. Note that the specific gravity means the bulk specific gravity (bulk density) in the case of an object having voids therein, such as a powder or granular material.

[0029] As described above, the conveyance amount calculation unit 113 calculates the area between the polygonal line (see dotted line 540) indicated by the conveyed object point cloud data and the polygonal line (see dotted line 510) indicated by the belt point cloud data as the cross-sectional area. The conveying amount calculation unit 113 calculates the cross-sectional area as the product of the difference between the average height calculated from the conveyed item point cloud data (see dotted line 540) and the average height calculated from the belt point cloud data (see dotted line 510) and the width of the belt 310 (the width of dotted lines 510, 540 (length at the X coordinate)). The conveyance amount calculation unit 113 calculates the weight conveyance amount by multiplying the volume conveyance amount by the specific gravity of the object to be conveyed.

[0030] <Transport amount calculation process> 7 is a flowchart of the transport amount calculation process according to the present embodiment. The process in FIG. In step S11, the measurement unit 111 acquires two-dimensional point cloud data that is the output of the sensor 200, and stores the data in the measurement value database .

[0031] In step S12, the detection unit 112 detects the end points of the two-dimensional point group indicated by the two-dimensional point group data and compares them with the reference value 140 to calculate the deviation of the belt 310. In step S13, if the deviation calculated in step S12 is equal to or smaller than a predetermined value, the detection unit 112 determines that there is no deviation (step S13→NO) and proceeds to step S15. If the deviation exceeds the predetermined value, the detection unit 112 determines that there is a deviation (step S13→YES) and proceeds to step S14.

[0032] In step S14, the transport amount calculation unit 113 adjusts the reference value 140. To explain in detail, the transport amount calculation unit 113 shifts the reference value 140 in the X-axis direction in accordance with the deviation. In step S15, the transport amount calculation unit 113 calculates a cross-sectional area based on the two-dimensional point group (see dotted line 510) of the reference value 140 adjusted in step S14 and the two-dimensional point group (see dotted line 540) acquired in step S11.

[0033] In step S16, the conveying amount calculation unit 113 multiplies the cross-sectional area calculated in step S15 by the belt speed of the belt 310 to calculate the conveying amount per unit time (volumetric conveying amount), and stores the calculated amount in the conveying amount database 150 in association with the acquisition time of the two-dimensional point cloud data (see step S11). The conveying amount calculation unit 113 may multiply the conveying amount per unit time by the specific gravity of the transported object to calculate the weight conveying amount per unit time, and store the weight conveying amount in the conveying amount database 150 together with the volume conveying amount.

[0034] <Features of the transport amount calculation device> The conveying amount calculation device 100 calculates the cross-sectional area of ​​the conveyed object based on a two-dimensional point cloud (see dotted line 540) showing the shape of the conveyed object surface and a two-dimensional point cloud (see dotted line 550) showing the shape of the belt 310 without the conveyed object, and calculates the volume by multiplying it by the belt speed. Furthermore, the conveying amount calculation device 100 calculates the weight. In this way, the conveying amount calculation device 100 can calculate the conveying amount with simpler equipment than the conventional technology.

[0035] Furthermore, the conveying amount calculation device 100 detects the end points of the belt 310, calculates the deviation in the left-right direction (X-axis direction), and adjusts the two-dimensional point cloud (see reference value 140, dotted line 510) that indicates the shape of the belt 310, which is the basis for calculating the cross-sectional area. In this way, the conveying amount calculation device 100 can calculate the conveying amount with high accuracy even if the belt 310 is deviated.

[0036] <Modification: Calculation of conveyance amount without calculating cross-sectional area> In the above embodiment, the conveyance amount calculation device 100 calculates the conveyance amount by obtaining the cross-sectional area of ​​the conveyed object, but the conveyance amount may be calculated without obtaining the cross-sectional area. The conveyance amount calculation unit 113 may calculate the conveyance weight using a correlation equation created from the relationship between the average height of the conveyed object calculated from the conveyance object point cloud data (see dotted line 530) and the conveyance weight (weight conveyance amount) measured by another means such as a Merrick belt scale. For example, the following linear equation (1) is created from the conveyance weight per unit time measured by the Merrick belt scale and the average value per unit time of the average height of the conveyance object calculated from the conveyance object point cloud data. The conveyance amount calculation unit 113 calculates the conveyance weight based on the average height of the conveyance object using the equation (1). Transport weight per unit time = (average height of transported goods per unit time) × A + B (1)

[0037] When calculating the average value of the average height of the transported objects per unit time, it is preferable to use the unit time measured by a different means and used to calculate the transported weight. The constants A and B in formula (1) are constants that differ depending on the type of transported object and the moving speed of the belt conveyor 300. In addition, the formula does not need to be a linear formula as long as it can obtain the correlation between the average height and transported weight of the transported objects. By using such a method, it is possible to calculate the conveyance amount without calculating the cross-sectional area of ​​the conveyed object.

[0038] As described above, the conveying amount calculation unit 113 calculates the average height of the transported object based on the transported object point cloud data (see dotted line 530) indicating the shape of the transported object transported by the belt conveyor 300, and calculates the weight conveying amount or volume conveying amount of the transported object based on the calculated average height using the correlation between the average height of the transported object and the weight conveying amount or volume conveying amount of the transported object (see equation (1)).

[0039] Other Modifications Although several embodiments of the present invention have been described above, these embodiments are merely illustrative and do not limit the technical scope of the present invention. The present invention can take various other embodiments, and various modifications such as omissions and substitutions can be made without departing from the gist of the present invention. These embodiments and their modifications are included in the scope and gist of the invention described in this specification, etc., and are included in the scope of the invention described in the claims and their equivalents. [Explanation of symbols]

[0040] 100 Transport amount calculation device 111 Measuring section 112 Detection unit 113 Transport amount calculation unit 128 Programs 130 Measurement Database 140 Reference value (point cloud data showing the pre-set belt shape) 150 Transport volume database 200 Sensors 300 Conveyor Belt 310 Belt 510 Dotted line (Point cloud data showing the pre-defined belt shape) 540 Dotted line (transport point cloud data) 550 Dotted line (Belt point cloud data)

Claims

1. The transport volume calculation device, A step of calculating the position of the belt in a direction perpendicular to the direction of travel and horizontally, based on point cloud data indicating the endpoints of the belt of the belt, which is included in the point cloud data of the conveyed object that shows the shape of the conveyed object being transported by the belt conveyor, A step of calculating belt point cloud data that shows the shape of the belt based on the position of the belt, A step of calculating the cross-sectional area of ​​the conveyed object based on the belt point cloud data and the conveyed object point cloud data, The process involves calculating the volume of the conveyed object based on the cross-sectional area and the belt speed of the belt conveyor. Method for calculating transport volume.

2. The step of calculating the belt point cloud data is performed based on the point cloud data representing the pre-set shape of the belt and the calculated position of the belt. The method for calculating the amount of material to be transported according to claim 1.

3. The step of calculating the area between the polyline shown by the transported object point cloud data and the polyline shown by the belt point cloud data as the cross-sectional area is performed. The method for calculating the amount of material to be transported according to claim 1.

4. The step of calculating the cross-sectional area is performed by multiplying the difference between the average height calculated from the conveyed object point cloud data and the average height calculated from the belt point cloud data, and the width of the belt. The method for calculating the amount of material to be transported according to claim 1.

5. The step of calculating the weight-based transport amount is performed by multiplying the volume-based transport amount by the specific gravity of the transported object. The method for calculating the amount of material to be transported according to claim 1.

6. The transport volume calculation device, A step of calculating the average height of an object being transported by a belt conveyor, based on point cloud data of the object showing its shape, The process involves a step of calculating the weight or volume of the conveyed object based on the calculated average height, using the correlation between the average height of the conveyed object and the weight or volume of the conveyed object. Method for calculating transport volume.

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