Method and system for detecting axial filling rate of cylindrical mixer

Abstract

The invention discloses an axial filling rate detection method for a cylindrical mixer, and the method comprises the following steps: a three-dimensional laser radar scans an unfilled material and a mixer after material filling from an outlet end, and obtains a three-dimensional point cloud A and a three-dimensional point cloud B respectively; extracting a data point cloud C and an inlet centroid O of an inlet, and a data point cloud C'and an outlet centroid O 'of an outlet from the three-dimensional point cloud A; calculating a vertical rotation angle theta and a flat rotation angle gamma of the cylindrical mixer based on the inlet centroids O and O ', and rotating the three-dimensional point cloud A and the three-dimensional point cloud B based on the vertical rotation angle theta and the flat rotation angle gamma; according to a set step length u, the mixer barrel rotation correction data set A'and the mixer barrel rotation correction data set B 'are cut into multiple groups of vertical surface patches in the axial direction of the mixer barrel; and calculating the axial filling rate of the barrel of the mixer at the corresponding position based on each group of vertical patches. The axial filling rate of the cylindrical mixer is calculated through the three-dimensional point cloud, periodically scanned by the three-dimensional laser, of the cylindrical mixer, and instant and accurate detection of the axial filling rate of the cylindrical mixer is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of steel sintering, and more specifically, relates to a method and system for detecting the filling rate in the axial direction of a cylindrical mixer. Background Art

[0002] In the whole sintering process, the granulation process is an important part of iron ore sintering. The quality of sintering mixed granulation is inseparable from the drum mixer and various process parameters in the mixing granulation process. The filling rate is a major factor affecting the granulation effect of the mixture.

[0003] The filling rate refers to the percentage of the material volume within a drum mixer to the drum volume. This has a significant impact on output, mixing, and pelletizing performance. When the filling rate is too low, the interaction forces between materials are too weak, making it difficult for adherent fine powder to adhere to the pellet cores, resulting in slow pellet growth and unfavorable pelletizing. This also results in low productivity and fails to meet production requirements. Increasing the filling rate, while maintaining the same mixing time, not only increases the output of the drum mixer but also increases the proportion of material in a rolling state, increasing the interaction forces between materials, promoting the adhesion of fine powder to the pellet cores and the gradual growth of pellets. This improves pelletizing performance and increases the average particle size of the sintered mix. However, if the filling rate of a drum mixer is too high, while output increases, the thickened material layer restricts and disrupts material movement, affecting the otherwise optimal motion trajectory, hindering mixing and pelletizing, and worsening pelletizing performance. Therefore, the actual filling rate of the mixer is directly related to the efficiency of the sintering process and the effectiveness of pelletizing the sintered raw materials.

[0004] In the prior art, the filling rate of a cylindrical mixer is calculated based on parameters such as the mixture flow rate, static bulk density, mixer size and mixing time. Since the static method is used to determine the mixture bulk density, the actual bulk density of the mixture after mixing and granulation in the mixer is significantly different from the static bulk density, and the mixing time of the mixture is also difficult to accurately determine, which leads to a large error in the calculated filling rate of the cylindrical mixer. Moreover, the above method can only determine the overall filling rate of the cylindrical mixer and cannot reflect changes in the axial filling rate of the cylindrical mixer. Summary of the Invention

[0005] The present invention provides a method for detecting the axial filling rate of a cylindrical mixer, aiming to improve at least one of the above problems.

[0006] The present invention is achieved by providing a method for detecting the axial filling rate of a cylindrical mixer, the method being specifically as follows:

[0007] (1) The 3D laser radar scans the unfilled cylindrical mixer and the filled mixer from the outlet to obtain 3D point clouds A and B, respectively;

[0008] (2) Extracting the data point cloud C and the inlet mass center O of the cylindrical mixer inlet, and the data point cloud C′ and the outlet mass center O′ of the cylindrical mixer outlet from the three-dimensional point cloud A;

[0009] (3) The vertical rotation angle θ and the horizontal rotation angle γ of the cylindrical mixer are calculated based on the inlet mass center O and the outlet mass center O′ of the cylindrical mixer. The three-dimensional point cloud A and the three-dimensional point cloud B are rotated based on the vertical rotation angle θ and the horizontal angle γ to form the mixer cylinder rotation dataset A′ and the mixer cylinder rotation dataset B′ respectively;

[0010] (4) Cutting the mixer barrel rotation data set A′ and the mixer barrel rotation data set B′ into multiple groups of vertical slices along the axial direction of the mixer barrel according to the set step length u;

[0011] (5) Based on each group of vertical slices, the axial filling rate of the mixer barrel at the corresponding position is calculated.

[0012] Furthermore, the extraction process of data point cloud C and data point cloud C′ is as follows:

[0013] (21) Based on the set scanning angle step α, the three-dimensional point cloud A is divided into a set of sectors SA.

[0014] (22) Calculate the i-th sector SA i The angle between each point and the o″yz plane is calculated, and the point cloud with the maximum angle or close to the maximum angle is identified as the import point cloud C of the i-th sector on the mixer. i (x c ,y c ,z c ), point cloud C i (x c ,y c ,z c ) into the data point cloud C, and the point cloud with the minimum angle and the point cloud close to the minimum angle is identified as the exit point cloud C of the i-th sector of the mixer i ′(x c ,y c ,z c ), point cloud C i ′(x c ,y c ,z c )Input the data point cloud C′;

[0015] (23) Traverse all sectors in the set of sectors SA.

[0016] Furthermore, the calculation formula of the inlet center of mass O of the cylindrical mixer based on the data point cloud C is as follows:

[0017]

[0018] Among them, J1 is the total number of data points in the data point cloud C.

[0019] Furthermore, the calculation formula of the outlet center of mass O′ of the cylindrical mixer based on the data point cloud C′ is as follows:

[0020]

[0021] Where J2 is the total number of data points in the data point cloud C′.

[0022] Furthermore, the calculation formulas for the vertical rotation angle θ and horizontal rotation angle γ of the mixer are:

[0023]

[0024] Among them, (x o ,y o ,z o ) is the coordinate of the inlet mass center O of the cylindrical mixer, (x o′ ,y o′ ,z o ') is the coordinate of the inlet center of mass O' of the cylindrical mixer.

[0025] Furthermore, the mixer barrel rotation data set A′ is expressed as follows:

[0026]

[0027] Furthermore, the mixer barrel rotation data set B′ is expressed as follows:

[0028]

[0029] Furthermore, the process of obtaining the filling rate of the kth group of vertical slices is as follows:

[0030] On the horizontal plane o"yz of the 3D laser scanning point, set the grid with y-axis spacing v and z-axis spacing r, and divide the vertical slice VA k , vertical surface VB k The point cloud is mapped to the divided grid cells, and the centroid of each grid is calculated to form a gridded point cloud dataset WA k and gridded point cloud dataset WB k ;

[0031] WA based point cloud dataset k Calculate vertical slice VA k Area: R k=uv∑|z agg |,(x agg′ ,y agg′ ,z agg′ )∈WA k , based on the gridded point cloud dataset WB k Calculate the vertical slice VB k Area: R′ k =uv∑|z bgg |,(x bgg′ ,y bgg′ ,z bgg′ )∈WB k , where u is the grid spacing of the vertical slices in the x-axis direction, and v is the grid spacing in the y-axis direction;

[0032] Calculate the axial filling rate of the kth group of vertical slices

[0033] The present invention also provides an axial filling rate detection system for a cylindrical mixer, the system comprising:

[0034] The processing unit is communicatively connected to the three-dimensional laser radar. The three-dimensional laser radar sends the three-dimensional point cloud B currently scanned to the processing unit. The processing unit stores the three-dimensional point cloud A scanned when the cylindrical mixer is not filled with material. The processing unit calculates the current axial filling rate of the cylindrical mixer based on the above-mentioned axial filling rate detection method of the cylindrical mixer.

[0035] Furthermore, the three-dimensional laser radar periodically scans the three-dimensional point cloud A of the drum mixer that is not filled with materials, and updates the three-dimensional point cloud A stored in the processing unit.

[0036] The present invention obtains three-dimensional point clouds of the cylindrical mixer and the mixture in the cylinder through three-dimensional laser periodic scanning, calculates the axial filling rate of the cylindrical mixer based on the scanned three-dimensional point cloud, and realizes instant and accurate detection of the axial filling rate of the cylindrical mixer, providing key technical support for further optimization of the mixing and granulation link in the sintering control process, thereby laying a solid foundation for improving the granulation effect and quality of the mixture. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A flow chart of a method for detecting the axial filling rate of a drum mixer provided in an embodiment of the present invention;

[0038] Figure 2 A schematic diagram of segmenting a three-dimensional point cloud into sectors according to an embodiment of the present invention;

[0039] Figure 3 A schematic diagram of extracting the inlet and outlet points of a mixer based on a sector point cloud provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0040] The specific implementation methods of the present invention will be further explained in detail below by describing the embodiments with reference to the accompanying drawings, so as to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention.

[0041] In actual sintering industrial production, the filling rate along the central axis of the cylindrical mixer is not uniform due to the influence of the inclination angle of the cylindrical mixer. Generally, the filling rate decreases from large to small from the feed end to the discharge end, especially at the outlet of the cylindrical mixer, where the change is more obvious. In addition, with the increase and uneven distribution of adhered materials on the inner wall of the cylindrical mixer, the axial filling rate of the mixer will also be uneven, which will affect the granulation effect of the mixer. The present invention provides a key technical basis for controlling the mixing and granulation process of sintering (such as: controlling the changes in the adhered materials on the inner wall and the timing of removing the adhered materials) and further optimizing (such as: improving the mixer liner, improving the uniformity of the axial filling rate, etc.) by real-time detection of changes in the axial filling rate of the cylindrical mixer.

[0042] Figure 1 This is a flow chart of a method for detecting the axial filling rate of a cylindrical mixer provided by an embodiment of the present invention. The method is specifically as follows:

[0043] (1) The 3D laser radar scans the unfilled cylindrical mixer and the filled mixer from the outlet to obtain 3D point clouds A and B, respectively;

[0044] The 3D laser radar scans the cylindrical mixer without material from the outlet end to obtain 3D point cloud A and 3D point cloud B. The 3D laser radar scans the cylindrical mixer filled with material from the outlet end to obtain 3D point cloud B. Of course, the point cloud data obtained by the 3D laser radar scanning contains some background point clouds, which need to be removed to form 3D point cloud A and 3D point cloud B.

[0045] (2) Extracting the data point cloud C of the cylindrical mixer inlet and the data point cloud C′ of the cylindrical mixer outlet from the three-dimensional point cloud A;

[0046] In the embodiment of the present invention, the extraction process of the data point cloud C and the data point cloud C′ is as follows:

[0047] (21) Based on the set scanning angle step α, the three-dimensional point cloud A is divided into a set of sectors SA.

[0048] In z a ≥0, the i-th sector SA i The specific meaning is as follows:

[0049]

[0050] In z a <0, the i-th sector SA i The specific meaning is as follows:

[0051]

[0052] Among them, (x a ,y a ,z a ) is the coordinate of the point in the three-dimensional point cloud A in the laser radar coordinate system, and the fan SA i like Figure 2 shown.

[0053] (22) Calculate the i-th sector SA i The angle between each point and the o″yz plane is calculated, and the point cloud with the maximum angle and the point cloud close to the maximum angle is identified as the i-th sector import point cloud C on the mixer. i (x c ,y c ,z c ), point cloud C i (x c ,y c ,z c ) into the data point cloud C, and the point cloud with the minimum angle and the point cloud close to the minimum angle is identified as the exit point cloud C of the i-th sector of the mixer i ′(x c ,y c ,z c ), point cloud C i ′(x c ,y c ,z c )Input the data point cloud C′;

[0054]

[0055] Due to the sector SA i There may be several points located at the inlet of the cylindrical mixer, whose angles with the o″yz plane are very close to the maximum angle, so the points whose difference with the maximum angle is less than the set difference threshold are identified as the points at the inlet of the cylindrical mixer. Similarly, due to the sector SA i There may be several points at the outlet of the cylindrical mixer, whose angles with the o"yz plane are very close to the minimum angle. Therefore, the points whose difference with the minimum angle is less than the set difference threshold are identified as the points at the outlet of the cylindrical mixer. Figure 3 Given sector SA i Schematic diagram of the extraction of the import point cloud and export point cloud in , o"x′ is the fan SA i The projection line of the line connecting the entry point, exit point and coordinate origin on the o″yz plane.

[0056] (23) Traverse all sectors in the set of sectors SA.

[0057] (3) Calculate the inlet centroid O of the mixer based on the inlet data point cloud C, and calculate the outlet centroid O′ of the mixer based on the outlet data point cloud C′;

[0058] In the embodiment of the present invention, the calculation formula of the center of mass O of the mixer volume inlet is as follows:

[0059]

[0060] Among them, J1 is the total number of data points in the data point cloud C.

[0061] In the embodiment of the present invention, the calculation formula of the outlet center of mass O' of the mixer is as follows:

[0062]

[0063] Where J2 is the total number of data points in the data point cloud C′.

[0064] (4) Calculate the vertical rotation angle θ and horizontal rotation angle γ of the mixer based on the inlet center of mass O and outlet center of mass O′ of the mixer;

[0065] In the embodiment of the present invention, the vertical rotation angle θ of the mixer is calculated as follows: The calculation formula of the horizontal rotation angle γ is:

[0066] (5) Rotate the three-dimensional point cloud A and the three-dimensional point cloud B based on the vertical rotation angle θ and the horizontal rotation angle γ to form the mixer barrel rotation dataset A′ and the mixer barrel rotation dataset B′ respectively;

[0067] In the embodiment of the present invention, the mixer barrel rotation data set A′ is represented as follows:

[0068]

[0069] In the embodiment of the present invention, the mixer barrel rotation data set B′ is represented as follows:

[0070]

[0071] (6) According to the set step length u, the mixer barrel rotation data set A′ and the mixer barrel rotation data set B′ are divided into multiple groups of vertical slices along the axial direction of the mixer barrel. The kth group of vertical slices is composed of the kth vertical slice VA of the mixer barrel. k and vertical piece VB k composition;

[0072] Slice the mixer cylinder rotation dataset A′ along the axial direction of the mixer cylinder according to the set step length u to form multiple vertical slices VA. The kth vertical slice VA k The details are as follows:

[0073] VA k (x′ ak ,y′ ak ,z′ ak )={(x′ ak ,y′ ak ,z′ ak )|x′ a ∈[ku,(k+1)u),k∈N,(x′ a ,y′ a ,z′ a )∈A′}, where N is a natural number.

[0074] Slice the mixer cylinder rotation dataset B′ along the axial direction of the mixer cylinder according to the set step length u to form multiple vertical slices VB. The kth vertical slice VB k The details are as follows:

[0075] VB k (x′ bk ,y′ bk ,z′ bk )={(x′ bk ,y′ bk ,z′ bk )|x′ b ∈[ku,(k+1)u),k∈N,(x′ b ,y′ b ,z′ b )∈B′}, where N is a natural number.

[0076] (7) The axial filling rate of the mixer barrel is calculated based on each group of vertical slices.

[0077] In the embodiment of the present invention, the filling rate of each group of vertical face sheets is calculated. The filling rates of all groups of vertical face sheets constitute the axial filling rate of the mixer barrel. The filling rate of the kth group of vertical face sheets is obtained as follows:

[0078] (71) The vertical slices VA k , vertical surface VB k Gridding

[0079] On the horizontal plane o″yz of the 3D laser scanning point, set a grid with a y-axis spacing of v and a z-axis spacing of r, and divide the vertical slice VA k , vertical surface VB kThe point cloud on the grid is mapped to the divided grid cells, and the centroid of each grid is calculated. o″ is the center of the laser radar coordinate system. The gridded point cloud dataset WA k The specific meaning is as follows:

[0080]

[0081] Among them, WA k (x agg′ ,y agg′ ,z agg′ ) indicates vertical slice VA k The point cloud on the y-axis is mapped to the g-th grid and the g′-th grid in the z-axis direction to form the centroid coordinates, G k1 Indicates VA in the vertical slice k The number of points mapped to the g-th grid in the y-axis direction and the g′-th grid in the z-axis direction.

[0082] In the embodiment of the present invention, the gridded point cloud dataset WB k The specific meaning is as follows:

[0083]

[0084] Among them, WB k (x bgg′ ,y bgg′ ,z bgg′ ) indicates vertical slice VB k The point cloud on the y-axis is mapped to the g-th grid and the g′-th grid in the z-axis direction to form the centroid coordinates, G k2 Indicates VB in the vertical slice k The number of points mapped to the g-th grid in the y-axis direction and the g′-th grid in the z-axis direction.

[0085] (72) Grid-based point cloud dataset WA k Calculate vertical slice VA k Area: R k =uv∑|z agg′ |,(x agg′ ,y agg′ ,z agg′ )∈WA k , based on the gridded point cloud dataset WB k Calculate the vertical slice VB k Area: R′ k =uv∑|z bgg′ |,(x bgg′ ,y bgg′ ,z bgg′ )∈WB k , where u is the grid spacing of the vertical slices in the x-axis direction, and v is the grid spacing in the y-axis direction;

[0086] (73) Calculate the axial filling rate of the kth group of vertical slices

[0087] The present invention also provides an axial filling rate detection system for a cylindrical mixer, the system comprising:

[0088] A three-dimensional laser radar is installed at the outlet of the cylindrical mixer;

[0089] The processing unit is connected to the three-dimensional laser radar for communication. The three-dimensional laser radar sends the three-dimensional point cloud B currently scanned to the processing unit. The processing unit stores the three-dimensional point cloud A scanned when the cylindrical mixer is not filled with material. The processing unit calculates the current axial filling rate of the cylindrical mixer based on the above-mentioned cylindrical mixer axial filling rate detection method.

[0090] The present invention uses periodic 3D laser scanning to obtain a 3D point cloud of the cylindrical mixer and the mixture inside the drum. Based on the scanned 3D point cloud, the axial filling rate of the cylindrical mixer is calculated. This enables real-time and accurate detection of the axial filling rate of the cylindrical mixer, providing key technical support for further optimization of the mixing and granulation process in the sintering control process, thereby laying a solid foundation for improving the granulation effect and quality of the mixture.

[0091] The present invention has been described exemplarily. Obviously, the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the scope of protection of the present invention.

Claims

1. A method for detecting the axial filling rate of a cylindrical mixer, characterized in that: The method is specifically as follows: (1) The 3D laser radar scans the unfilled cylindrical mixer and the filled mixer from the outlet to obtain 3D point clouds A and B, respectively; (2) Extracting the data point cloud C and the inlet mass center O of the cylindrical mixer inlet, and the data point cloud C′ and the outlet mass center O′ of the cylindrical mixer outlet from the three-dimensional point cloud A; (3) The vertical rotation angle θ and the horizontal rotation angle γ of the cylindrical mixer are calculated based on the inlet mass center O and the outlet mass center O′ of the cylindrical mixer. The three-dimensional point cloud A and the three-dimensional point cloud B are rotated based on the vertical rotation angle θ and the horizontal angle γ to form the mixer cylinder rotation dataset A′ and the mixer cylinder rotation dataset B′ respectively; (4) Cutting the mixer barrel rotation data set A′ and the mixer barrel rotation data set B′ into multiple groups of vertical slices along the axial direction of the mixer barrel according to the set step length u; (5) Based on each group of vertical slices, the axial filling rate of the mixer barrel at the corresponding position is calculated.

2. The method for detecting the axial filling rate of a cylindrical mixer according to claim 1, wherein: The extraction process of data point cloud C and data point cloud C′ is as follows: (21) Based on the set scanning angle step α, the three-dimensional point cloud A is divided into a set of sectors SA. (22) Calculate the i-th sector SA i The angle between each point and the o″yz plane is calculated, and the point cloud with the maximum angle or close to the maximum angle is identified as the import point cloud C of the i-th sector on the mixer. i (x c ,y c ,z c ), point cloud C i (x c ,y c ,z c ) into the data point cloud C, and the point cloud with the minimum angle and the point cloud close to the minimum angle is identified as the exit point cloud C of the i-th sector of the mixer i ′(x c ,y c ,z c ), point cloud C i ′(x c ,y c ,z c )Input the data point cloud C′; (23) Traverse all sectors in the set of sectors SA.

3. The method for detecting the axial filling rate of a cylindrical mixer according to claim 2, wherein: The calculation formula of the inlet center of mass O of the cylindrical mixer based on the data point cloud C is as follows: Among them, J1 is the total number of data points in the data point cloud C.

4. The method for detecting the axial filling rate of a cylindrical mixer according to claim 2, wherein: The calculation formula of the outlet center of mass O′ of the cylindrical mixer based on the data point cloud C′ is as follows: Where J2 is the total number of data points in the data point cloud C′.

5. The method for detecting the axial filling rate of a cylindrical mixer according to claim 1, wherein: The calculation formulas for the vertical rotation angle θ and horizontal rotation angle γ of the mixer are: Among them, (x o ,y o ,z o ) is the coordinate of the inlet mass center O of the cylindrical mixer, (x o′ ,y o′ ,z o′ ) is the coordinate of the inlet center of mass O' of the cylindrical mixer.

6. The method for detecting the axial filling rate of a cylindrical mixer according to claim 1, wherein: The mixer barrel rotation data set A′ is expressed as follows:

7. The method for detecting the axial filling rate of a drum mixer according to claim 1, wherein: The mixer barrel rotation data set B′ is expressed as follows:

8. The method for detecting the axial filling rate of a cylindrical mixer according to claim 1, wherein: The process of obtaining the filling rate of the kth group of vertical slices is as follows: On the horizontal plane o"yz of the 3D laser scanning point, set the grid with y-axis spacing v and z-axis spacing r, and divide the vertical slice VA k , vertical surface VB k The point cloud is mapped to the divided grid cells, and the centroid of each grid is calculated to form a gridded point cloud dataset WA k and gridded point cloud dataset WB k ; WA based point cloud dataset k Calculate vertical slice VA k Area: R k =uv∑|z agg′ |,(x agg′ ,y agg′ ,z agg′ )∈WA k , based on the gridded point cloud dataset WB k Calculate the vertical slice VB k Area: R′ k =uv∑|z bgg′ |,(x bgg′ ,y bgg′ ,z bgg′ )∈WB k , where u is the grid spacing of the vertical slices in the x-axis direction, and v is the grid spacing in the y-axis direction; Calculate the axial filling rate of the kth group of vertical slices 9. A system for detecting the axial filling rate of a cylindrical mixer, characterized in that: The system comprises: The processing unit is communicatively connected to the three-dimensional laser radar. The three-dimensional laser radar sends the three-dimensional point cloud B currently scanned to the processing unit. The processing unit stores the three-dimensional point cloud A scanned when the cylindrical mixer is not filled with material. The processing unit calculates the current axial filling rate of the cylindrical mixer based on the axial filling rate detection method of the cylindrical mixer described in any one of claims 1 to 8.

10. The axial filling rate detection system of a drum mixer according to claim 9, characterized in that: The three-dimensional laser radar periodically scans the three-dimensional point cloud A of the drum mixer that is not filled with materials, and updates the three-dimensional point cloud A stored in the processing unit.

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