A method for stacking by a bucket-wheel stacker-reclaimer for optimizing yard utilization

Abstract

The application relates to the technical field of control, and discloses a bucket-wheel stacker-reclaimer stacking method for optimizing yard utilization, which comprises the following steps: establishing a yard three-dimensional coordinate system and setting a reference point; obtaining three-dimensional point cloud data of a material pile by using a laser radar, screening first mapping three-dimensional points, and determining coordinate data of the first mapping three-dimensional points; sequentially connecting primary stacking points to form a stacking path; performing first-time stacking according to the stacking path, and performing stacking work of a next primary stacking point after the material pile reaches a stacking height; updating the stacking height, and repeating a round of stacking work from the first primary stacking point; determining a bearable parameter between at least two adjacent primary stacking points, screening secondary stacking points, and moving a stacker-reclaimer to the secondary stacking points to perform stacking. The next round of stacking is performed according to the stacking path and staggered from the stacking positions of the primary stacking points, and multi-point stacking is performed around one primary stacking point, so that the space utilization rate of the region around each primary stacking point is improved.

Description

Technical Field

[0001] This invention relates to the field of control technology, and more specifically to a method for optimizing stockpile utilization using a bucket wheel stacker-reclaimer. Background Technology

[0002] Stacker cranes are lifting and transport machinery that transfer bulk materials from conveyor belts and stack them in a stockyard according to certain procedures. Stacker cranes usually use a row-by-row stacking method. The slewing angle is changed and the next row is switched only when the boundary position of the planned area is reached. After the first stacking point of the next row reaches the predetermined stacking height, only the position of the trolley is moved to switch to the next stacking point. In this way, the slewing mechanism is only operated at the boundary position, and only the trolley is moved when switching stacking points in the same row.

[0003] Materials from the same batch need to be stacked together. If the stacking area is too short or too long, it will lead to high planning difficulty. To solve the above problems, the invention patent with publication number CN107324075B in the prior art provides a stacking method based on the lateral movement of the stacker. It adopts the column stacking method, stacking materials at each stacking point one by one along the column direction.

[0004] In the stockpile, materials come in various forms such as granules and powders. As the materials fall naturally, the size and type of the particles will cause different angles of repose in the stockpile. During the stockpiling process, each stockpile stops stockpiling after reaching its maximum height. Due to the existence of the angle of repose, there is a large space between adjacent stockpiles where the height corresponding to the space has not reached the maximum height, resulting in low space utilization of the entire stockpile. Summary of the Invention

[0005] To address this issue, the present invention provides a method for stacking materials using a bucket wheel stacker-reclaimer to optimize the utilization rate of the stockyard. This method effectively solves the technical problem in the prior art where the height of adjacent stockpiles does not reach the maximum stockpile height due to the large space between them, resulting in low utilization of the entire stockyard space.

[0006] To solve the above-mentioned technical problems, the present invention specifically provides the following technical solution: a method for stacking materials using a bucket wheel stacker-reclaimer to optimize stockpile utilization, comprising the following steps: Establish a three-dimensional coordinate system O0-X0Y0Z0 for the stockyard, and set several reference points in an array on the X0Y0 plane within the stockyard area based on the three-dimensional coordinate system of the stockyard; The three-dimensional point cloud data of the stockpile is obtained by scanning the stockpile with lidar. The first mapping three-dimensional point with a mapping relationship with the reference point is selected based on the three-dimensional point cloud data, and the coordinate data of each first mapping three-dimensional point is determined. Several primary stockpiling points are arrayed on the X0Y0 plane within the stockyard area, and the primary stockpiling points are connected sequentially to form a stockpiling path; Set the stacking height, and start the first stacking operation from the position near the stockyard entrance and stacker according to the stacking path. After the stacking height is reached, proceed to the next primary stacking point until the last primary stacking point is reached. Update the stacking height, starting from the first primary stacking point and repeating the stacking operation with staggered primary stacking point positions until the maximum stacking height is reached; Based on the coordinate data of the first mapped three-dimensional point, determine the accommodating parameters between at least two adjacent primary stacking points, select the center point corresponding to the maximum accommodating parameter as the secondary stacking point, move the stacker to the secondary stacking point to stack the material until the maximum stacking height is reached, and repeat the above steps until all reference points reach the maximum stacking height.

[0007] Furthermore, each primary stockpile point coincides with a reference point, and the distances between adjacent primary stockpile points are the same, as are the distances between adjacent reference points. Where L = nl, n is an integer, L is the distance between adjacent primary stacking points, and l is the distance between adjacent reference points.

[0008] Furthermore, the lidar is placed on the boom of the stacker; With the stacker as the origin, construct the stacker coordinate system O1-X1Y1Z1, and the X1OZ1 plane rotates following the rotation of the stacker boom; A radar coordinate system O-XYZ is constructed with the lidar as the origin.

[0009] Furthermore, the coordinates of each first mapped 3D point in the 3D coordinate system O0-X0Y0Z0 of the stockyard are calculated using the following formula from the 3D point cloud data acquired by the lidar. ; In the formula, R1 is the rotation matrix of the O-XYZ coordinate system relative to the O1-X1Y1Z1 coordinate system. Let O be the translation of the O-XYZ coordinate system relative to the O1-X1Y1Z1 coordinate system. , L is the length of the stacker boom, H is the height of the stacker's rotation center, θ is the pitch angle of the stacker boom, and R2 is the rotation matrix of the O1-X1Y1Z1 coordinate system relative to the O0-X0Y0Z0 coordinate system. Let Δ be the translation of the O1-X1Y1Z1 coordinate system relative to the O0-X0Y0Z0 coordinate system. This is the distance from the center of rotation of the stacker to the origin of the stockyard coordinate system.

[0010] Furthermore, the method of connecting the primary stockpiling points to form a stockpiling path includes the following steps: Arrange all primary stacking points in columns along the direction perpendicular to the translation of the stacker; Connect the primary stacking points in each column sequentially; Connect the primary stockpiling point at the end of the first column to the primary stockpiling point at the end of the second column, connect the primary stockpiling point at the beginning of the second column to the primary stockpiling point at the beginning of the third column, and so on, until a continuous curved stockpiling path is formed.

[0011] Furthermore, before stockpiling, a stockpiling height h1 is set, and the first stockpiling is carried out from the position near the stockyard entrance and the stockpile machine according to the stockpiling path. After the stockpile reaches the stockpiling height h1, the stockpiling work of the next primary stockpiling point is carried out until the last primary stockpiling point is reached, thus completing the first round of stockpiling. Update the stockpile height to h1+h0. Start the second round of stockpiling from the position near the stockyard entrance and the stockpile machine according to the stockpiling path. After the stockpile reaches the stockpile height h1+h0, proceed to the next primary stockpile point until the last primary stockpile point is reached, completing the second round of stockpiling. ...and so on, until the Nth round of material stacking is completed, h1+Nh0≤A and h1+(N+1)h0≥A, and the curved material stacking work is stopped after the Nth round of material stacking is completed; Where A is the maximum stacking height, and the stacking position of each round is staggered from the stacking position of the primary stacking point and the stacking position of the previous round.

[0012] Further, based on the coordinate data of the first mapped three-dimensional points, the allowable parameters between at least two adjacent primary stockpiling points are determined, and the center point corresponding to the maximum allowable parameter is selected as the secondary stockpiling point, including the following steps: Establish a line between two adjacent primary stockpiling points, and use the midpoint of the line as the base point; With the base point as the center and R as the radius, draw a circular containment area, obtain the height value Q of the second mapped 3D point corresponding to each reference point within the circular containment area, and filter out the reference point with the largest height value. in, L is the distance between adjacent primary stockpiling points, the second mapped three-dimensional point has a mapping relationship with the corresponding reference point, and Q is the vertical coordinate of the corresponding second mapped three-dimensional point in the stockpile three-dimensional coordinate system O0-X0Y0Z0. Using the reference point with the largest height value as the center and R as the radius, redraw the circular containment area, obtain the height value Q of the second mapped 3D point corresponding to each reference point within the circular containment area, and then select the reference point with the largest height value as the center point. The selected center points are aggregated and their corresponding accommodateable parameters within the circular containment range are calculated. The center point corresponding to the maximum accommodateable parameter is selected as the secondary stacking point.

[0013] Furthermore, the reference point and the first mapped three-dimensional point that has a mapping relationship with it have the same horizontal and vertical coordinates in the three-dimensional coordinate system O0-X0Y0Z0 of the stockpile. The reference point and the second mapped three-dimensional point that has a mapping relationship with it have the same horizontal and vertical coordinates in the three-dimensional coordinate system O0-X0Y0Z0 of the stockyard.

[0014] Furthermore, for one of the center points, obtain all reference points within its corresponding circular containment area and the height values ​​Q1, Q2, Q3, ..., Q of the corresponding second mapped 3D points. n The accommodability parameter S is calculated using the following formula:

[0015] Where n is the number of reference points within the circular area, and K is a constant.

[0016] Furthermore, after selecting the secondary stockpiling points, materials are stockpiled at the secondary stockpiling points until the secondary stockpiling points reach the maximum stockpiling height; If the stacker does not completely unload during a single stacking operation, select the nearest center point to continue the stacking process.

[0017] Compared with the prior art, the present invention has the following advantages: In this invention, the first round of material stacking is carried out sequentially according to the stacking path. Then, the next round of material stacking is carried out according to the stacking path but staggered from the primary stacking point. This process is repeated multiple times until the maximum stacking height is reached. Multiple stacking points are stacked around a primary stacking point. In this way, by using a multi-round staggered stacking method, multiple rounds of stacking are carried out around the same primary stacking point. The stacking position of each round is staggered from the previous round and the primary point position, which reduces the space idle caused by the angle of repose at a single point and improves the space utilization rate of the area around each primary stacking point. Furthermore, after the stockpiling work at the primary stockpiling points is completed, the capacity parameters between at least two adjacent primary stockpiling points are calculated, and secondary stockpiling points are selected based on the capacity parameters. Then, the stockpiling work at the secondary stockpiling points is carried out, which effectively utilizes the low-lying areas between the primary stockpiling points and effectively improves the overall utilization rate of the stockyard. Attached Figure Description

[0018] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0019] Figure 1 A flowchart of a bucket wheel stacker-reclaimer stacking method for optimizing stockpile utilization is provided in an embodiment of the present invention; Figure 2 This is a schematic diagram showing the distribution of reference points and primary stockpiling points on the X0Y0 plane in an embodiment of the present invention; Figure 3 This is a schematic diagram showing the distribution of the O0-X0Y0Z0 coordinate system, the O1-X1Y1Z1 coordinate system, and the O-XYZ coordinate system in an embodiment of the present invention. Figure 4 This is a schematic diagram showing the positions of the reference point and the first mapped three-dimensional point in an embodiment of the present invention. Figure 5 This is a schematic diagram of the material stacking path in an embodiment of the present invention; Figure 6 This is a schematic diagram of the multiple stacking positions in the primary stacking point in an embodiment of the present invention; Figure 7 This is a schematic diagram illustrating the construction of a circular containment area between adjacent primary stockpiling points according to the present invention. Figure 8 This is a schematic diagram illustrating the reconstruction of the circular accommodating area according to the present invention; Figure 9 This is a schematic diagram of the bucket wheel stacker-reclaimer of the present invention; Figure 10 This is the main control interface for using the method of the present invention; Figure 11 This is the main control interface for using the method of the present invention; Figure 12 The plant area status is displayed on the main control interface using the method of this invention; The components include: 1. Traveling mechanism; 2. Rotating platform; 3. Pitching mechanism; 4. Boom; 5. Bucket wheel mechanism; 6. Counterweight; 7. LiDAR; 8. Angle encoder; 9. North... Dou sensor. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] like Figure 1 As shown, the present invention provides a method for optimizing stockpile utilization using a bucket wheel stacker-reclaimer, comprising the following steps: Establish a three-dimensional coordinate system O0-X0Y0Z0 for the stockyard, and set several reference points in an array on the X0Y0 plane within the stockyard area based on the three-dimensional coordinate system of the stockyard; The three-dimensional point cloud data of the stockpile was obtained by scanning the stockpile with a LiDAR 7. Based on the three-dimensional point cloud data, the first mapping three-dimensional points that have a mapping relationship with the reference points were selected, and the coordinate data of each first mapping three-dimensional point was determined. Several primary stockpiling points are arrayed on the X0Y0 plane within the stockyard area. The primary stockpiling points are connected sequentially to form a stockpiling path. The stockpiling height is set, and the first stockpiling is carried out according to the stockpiling path, starting from the position near the stockyard entrance and the stockpile machine. After the stockpile reaches the stockpiling height, the stockpiling work of the next primary stockpiling point is carried out until the last primary stockpiling point is reached. Update the stacking height, starting from the first primary stacking point and repeating the stacking operation with staggered primary stacking point positions until the maximum stacking height is reached; The three-dimensional point cloud data of the material pile is scanned and updated in real time. Based on the coordinate data of the first mapped three-dimensional point and the material repose angle, the accommodating parameters between adjacent primary stacking points are dynamically determined. The center point corresponding to the maximum accommodating parameter is selected as the secondary stacking point. The stacker moves to the secondary stacking point to stack the material until the maximum stacking height is reached. The above steps are repeated until all reference points reach the maximum stacking height.

[0022] In this invention, the first round of material stacking is carried out sequentially according to the stacking path. Then, the next round of material stacking is carried out according to the stacking path but staggered from the primary stacking point. This process is repeated multiple times until the maximum stacking height is reached. Multiple stacking points are carried out around a primary stacking point, which improves the space utilization rate of the area around each primary stacking point. Furthermore, after the stockpiling work at the primary stockpiling points is completed, the capacity parameters between at least two adjacent primary stockpiling points are calculated, and secondary stockpiling points are selected based on the capacity parameters. Then, the stockpiling work at the secondary stockpiling points is carried out, which effectively utilizes the low-lying areas between the primary stockpiling points and effectively improves the overall utilization rate of the stockyard.

[0023] The number of reference points is much greater than the number of primary stockpiling points. The purpose of setting up reference points is to obtain the height values ​​of various locations on the stockpile, thereby determining the low-lying conditions of the area surrounding the stockpile.

[0024] Each primary stockpile point coincides with a reference point, which is equivalent to setting a primary stockpile point within the reference point. The distance between adjacent primary stockpile points is the same, and the distance between adjacent reference points is the same. Where L = nl, n is an integer, L is the distance between adjacent primary stockpiling points, and l is the distance between adjacent reference points.

[0025] by Figure 2 For example, in the figure, solid dots represent primary stockpiling points and reference points, while hollow dots represent reference points. A primary stockpiling point is set for every four reference points. In practical applications, to obtain a more comprehensive understanding of the state of the surrounding area of ​​each stockpile, more reference points should be set to correspond to a primary stockpiling point. In the figure, the value of n is 4.

[0026] Since the midpoint between adjacent primary stockpiles needs to be obtained, and the height of that midpoint needs to be determined, the value of n should be set to an even number. This way, the midpoint between adjacent primary stockpiles will necessarily correspond to a reference point, making it easier to obtain the height of the midpoint.

[0027] In this invention, the coordinate data of the first mapped three-dimensional point corresponding to each reference point in the three-dimensional coordinate system O0-X0Y0Z0 of the stockpile is obtained based on the lidar 7. Generally, it is assumed that the X0Y0 plane in the three-dimensional coordinate system O0-X0Y0Z0 of the stockpile coincides with the ground of the stockpile. If the coordinate data of the first mapped three-dimensional point corresponding to a certain reference point is (X0, Y0, Z0), then the height value of the first mapped three-dimensional point corresponding to the reference point is Z0. The first mapped three-dimensional point can be regarded as a point on the surface of the stockpile.

[0028] In the above embodiments, such as Figure 4 As shown, the reference point is located on the X0Y0 plane, and the first mapped 3D point is located on the surface of the stockpile. The reference point and the first mapped 3D point that have a mapping relationship with it have the same horizontal and vertical coordinates in the stockpile 3D coordinate system O0-X0Y0Z0. It can be seen that the reference point is only to pre-create a uniform set of positions on the X0Y0 plane, and to obtain the height value of the stockpile at the corresponding position based on this uniform set of positions. By using the height values ​​of multiple sets of stockpile at different positions, the approximate shape of the stockpile can be determined.

[0029] In this invention, the process of converting the three-dimensional point cloud data acquired by the lidar 7 into the coordinate data of the first mapped three-dimensional point is as follows: Place the lidar 7 on the stacker boom 4; like Figure 3 As shown, with the stacker as the origin, a stacker coordinate system O1-X1Y1Z1 is constructed, and the X1OZ1 plane rotates following the rotation of the stacker boom 4; With lidar 7 as the origin, a radar coordinate system O-XYZ is constructed.

[0030] The coordinates of each first-mapped three-dimensional point in the three-dimensional coordinate system O0-X0Y0Z0 of the stockyard are calculated using the following formula based on the three-dimensional point cloud data acquired by the lidar 7.

[0031] In the formula, R1 is the rotation matrix of the O-XYZ coordinate system relative to the O1-X1Y1Z1 coordinate system. Let O be the translation of the O-XYZ coordinate system relative to the O1-X1Y1Z1 coordinate system. , L is the length of the stacker boom, H is the height of the stacker's rotation center, θ is the pitch angle of the stacker boom, and R2 is the rotation matrix of the O1-X1Y1Z1 coordinate system relative to the O0-X0Y0Z0 coordinate system. Let Δ be the translation of the O1-X1Y1Z1 coordinate system relative to the O0-X0Y0Z0 coordinate system. This is the distance from the center of rotation of the stacker to the origin of the stockyard coordinate system.

[0032] In the above embodiments, in order to obtain the pitch angle of the stacker boom 4, an angle encoder 8 can be installed at the rotation point of the stacker boom 4. In order to obtain the distance from the stacker rotation center to the origin of the stockyard coordinate system, a Beidou sensor 9 can be installed at the stacker rotation center.

[0033] After the above steps, the coordinate data of each first mapped 3D point can be determined. The height value of the first mapped 3D point corresponding to the reference point can be obtained through the coordinate data, so as to facilitate subsequent data processing.

[0034] The path planning in this invention mainly involves two processes: a primary path planning process and a secondary path planning process.

[0035] The initial path planning process involves stacking materials in columns, specifically, as follows: Figure 5 As shown, the method of connecting primary stockpiling points to form a stockpiling path includes the following steps: Arrange all primary stacking points in columns along the direction perpendicular to the stacker's translation; Connect the primary stacking points in each column sequentially; Connect the primary stockpiling point at the end of the first column to the primary stockpiling point at the end of the second column, connect the primary stockpiling point at the beginning of the second column to the primary stockpiling point at the beginning of the third column, and so on, until a continuous curved stockpiling path is formed.

[0036] In this context, the Y0 direction is the translational direction of the stacker, the column direction is the X0 direction, and the ends of each column are connected to form the final curved stacking path. Initially, the stacking operation is carried out by stacking materials one by one according to the stacking path.

[0037] Once the material is stacked according to the stacking path, it is considered that one round of regular stacking work is completed. In order to improve the utilization rate of the stockyard space, the present invention performs multiple rounds of the above-mentioned regular stacking work. Specifically, before stacking, the stacking height h1 is set, and the first stacking is carried out according to the stacking path, starting from the position near the stockyard entrance and the stacker. After the material pile reaches the stacking height h1, the stacking work of the next primary stacking point is carried out until the last primary stacking point is reached, thus completing the first round of stacking. Update the stockpile height to h1+h0. Start the second round of stockpiling from the position near the stockyard entrance and the stockpile machine according to the stockpiling path. After the stockpile reaches the stockpile height h1+h0, proceed to the next primary stockpile point until the last primary stockpile point is reached, completing the second round of stockpiling. ...and so on, until the Nth round of material stacking is completed, h1+Nh0≤A and h1+(N+1)h0≥A, and the curved material stacking work is stopped after the Nth round of material stacking is completed; Where A is the maximum stacking height, and the stacking position of each round is staggered from the stacking position of the primary stacking point and the stacking position of the previous round.

[0038] In the above embodiments, multiple rounds of regular material stacking are performed, such as... Figure 6 As shown, the solid point is the primary stockpiling point, and the points around the solid point are the stockpiling points for the second, third, and so on. The stockpiling position of the first round is directly opposite the primary stockpiling point, while the stockpiling position of the second round is offset from the primary stockpiling point. The stockpiling position of the third round is offset from the primary stockpiling point and the stockpiling position of the second round, and so on. After multiple rounds of stockpiling, a relatively evenly distributed stockpile can be formed at a certain primary stockpiling point.

[0039] After the Nth round of material stacking, if the current stacking height has not yet reached or has just reached the maximum stacking height, and the stacking height in the next round will inevitably be greater than the maximum stacking height, then after this round of material stacking, the regular material stacking work is stopped, and subsequent decentralized material stacking work begins.

[0040] After completing multiple rounds of regular material stacking based on the results of the primary path planning, secondary path planning is required.

[0041] Secondary path planning mainly involves identifying low-lying areas for stockpiling, in order to fully utilize the low-lying areas in the stockpile that have not yet reached their maximum stockpiling height. Specifically, based on the coordinate data of the first mapped 3D points, the allowable parameters between at least two adjacent primary stockpiling points are determined, and the center point corresponding to the maximum allowable parameter is selected as the secondary stockpiling point. This includes the following steps: Establish a line between two adjacent primary stockpiling points, and use the midpoint of the line as the base point; With the base point as the center and R as the radius, draw a circular containment area, obtain the height value Q of the second mapped 3D point corresponding to each reference point within the circular containment area, and filter out the reference point with the largest height value. in, L is the distance between adjacent primary stockpile points. The second mapped three-dimensional point has a mapping relationship with the corresponding reference point. Q is the vertical coordinate of the corresponding second mapped three-dimensional point in the stockpile three-dimensional coordinate system O0-X0Y0Z0. Using the reference point with the largest height value as the center and R as the radius, redraw the circular containment area, obtain the height value Q of the second mapped 3D point corresponding to each reference point within the circular containment area, and then select the reference point with the largest height value as the center point. The selected center points are aggregated and their corresponding accommodateable parameters within the circular containment range are calculated. The center point corresponding to the maximum accommodateable parameter is selected as the secondary stacking point.

[0042] Among them, the reference point and the second mapped three-dimensional point that has a mapping relationship with it have the same horizontal and vertical coordinates in the three-dimensional coordinate system O0-X0Y0Z0 of the stockyard.

[0043] Taking several adjacent primary stockpiling points as an example, such as Figure 7 As shown, firstly, a line is established between two primary stockpiling points a and b. The midpoint e of the line is taken as the base point. With the base point e as the center and R as the radius, a circular containment range is drawn. The height value Q of the second mapped three-dimensional point corresponding to each reference point within the circular containment range is obtained. The reference point f with the largest height value is then selected. like Figure 8 As shown, with the reference point f with the largest height value as the center and R as the radius, the circular containment area is redrawn. The height value Q of the second mapped 3D point corresponding to each reference point within the circular containment area is obtained. Then, the reference point f with the largest height value is selected as the center point f.

[0044] The second circular containment range encompasses reference points a, b, c, and d. Therefore, the selected center point f can be regarded as the center point between reference points a, b, c, and d. Following the above steps, the center point between each pair of adjacent primary stockpiling points is selected. Then, the containment parameters within the circular containment range corresponding to all center points are calculated, and the center point corresponding to the maximum containment parameter is selected as the secondary stockpiling point.

[0045] In the above embodiments, if the point with the largest height value found after drawing the circular containment area for the second time is inconsistent with the point with the largest height value found in the first time, the circular containment area can be drawn again with the point with the largest height value found in the second time as the center and R as the radius. The point with the largest height value is searched for a third time, and so on, until the point with the largest height value found is consistent with the point with the largest height value found in the previous search. The search is then stopped, and the point with the largest height value is used as the center point. This step is to find the lowest depression position in a certain area.

[0046] The R value is used to form a circular containment area that can just encompass the four adjacent primary stockpiles. In actual operation, the lowest position is usually at the center of the four adjacent primary stockpiles. This value can better find the low-lying position between the four adjacent primary stockpiles, which is more convenient for path planning. The R value can also be adjusted according to the actual situation.

[0047] In this invention, the accommodateability parameter can be considered as a reference value for a accommodating volume within a circular accommodating range. The larger the accommodateability parameter, the lower the depression in the region. Specifically, for one center point, all reference points within its corresponding circular accommodating range and the height values ​​Q1, Q2, Q3, ..., Q6 corresponding to the second mapped three-dimensional points are obtained. n The accommodability parameter S is calculated using the following formula:

[0048] Where n is the number of reference points within the circular area, and K is a constant.

[0049] In the above embodiments, the value of K can be any constant. The lower the depression within the circular containment area, the lower the height value Q, and the smaller the calculated height value. Then the final containment parameter S is larger. The larger the value of S, the greater the difference between the current height and the maximum stacking height in the area, and the more suitable it is for priority stacking. This confirms that the containment parameter can well characterize the containment volume and depression degree within a certain circular containment area.

[0050] After the above steps, the center point corresponding to the maximum accommodative parameter can be selected, which is the center point of the lowest depression area. This center point is used as the secondary material stacking point. After selecting the secondary material stacking point, material is stacked at the secondary material stacking point until the secondary material stacking point reaches the maximum stacking height.

[0051] Therefore, secondary path planning aims to identify the lowest depression area to reduce the number of times materials are piled up in a dispersed manner. Assuming that the amount of material unloaded at one time is fixed, piling up materials in the lowest depression area can effectively place the material directly in that depression area. However, in higher (non-depression) areas, the piling location may need to be changed after a period of time to find the next piling location.

[0052] In the above implementation scenarios, it is also possible that material cannot be discharged in one go in low-lying areas. After the material is piled up to the required height in low-lying areas, it is necessary to match a new material pile point. In response to this, the present invention makes the following design: when the stacker has not completely unloaded the material in a single material pile, a nearby center point is selected to continue the material pile work. This design can complete the material pile work of the stacker more efficiently in a single pile.

[0053] When the stacker has not completely unloaded the material during a single stacking operation, the center point is selected from which the straight-line distance from the current secondary stacking point is less than 1 / 2 of the distance between the adjacent primary stacking points, thus achieving the selection of the nearest center point.

[0054] In practice, if the material stacking height in all low-lying areas has reached the standard, but the height values ​​at all reference points still do not reach the maximum stacking height, the following two methods can be used for subsequent material stacking planning: The first method is to set a value d, take the reference point that does not meet the standard as the base point, and calculate the height values ​​of the d nearest reference points around it as the intolerable parameter of the area. The reference point with the lowest intolerant parameter is selected as the third-level stockpiling point, and the next stockpiling operation is carried out at the third-level stockpiling point; The second method: directly compare the height values ​​of each reference point; The reference point with the lowest height value is selected as the third-level stacking point, and the next stacking operation is carried out at the third-level stacking point.

[0055] While the above two approaches can further optimize the utilization rate of the stockpile based on the present invention, they also make the stockpiling steps more numerous and the process more complicated. Therefore, the stockpiling work can be paused after the secondary path planning is completed. In addition, a threshold for the capacity parameter can be set. When the capacity parameter of a certain circular capacity range is lower than the threshold, the secondary path planning can continue to carry out the subsequent stockpiling. When all the capacity parameters are higher than the threshold, the stockpiling work is paused.

[0056] Once the material in a certain area has been cleared, the primary path planning for that stockpile area can be restarted to carry out multiple rounds of regular stockpiling operations.

[0057] The following example, using coal storage in a port bulk cargo yard, provides a concrete illustration of the patented technology's practical application: A coal storage yard at a port is a rectangular area, 100m long and 50m wide, where coal needs to be stacked (angle of repose approximately 35°), with a maximum stacking height A=8m. The stacker crane has a boom length L=15m, a slewing center height H=3m, and is equipped with a LiDAR 7, an angle encoder 8, and BeiDou positioning.

[0058] Step 1: Establish coordinate system and reference points Establish a three-dimensional coordinate system O0-X0Y0Z0 for the stockyard: the origin O0 is the lower left corner of the stockyard, the X0 axis is along the length of the stockyard (0-100m), the Y0 axis is along the width (0-50m), and the Z0 axis is the vertical height (0-8m).

[0059] Set reference points: Distribute them in an array at 2m intervals in the X0Y0 plane, that is, the coordinates of the reference points are (2i,2j,0), where i=0,1,...,50 (X0 direction) and j=0,1,...,25 (Y0 direction), for a total of 51×26=1326 reference points.

[0060] Step 2: Primary Stockpiling Point and Path Planning Primary stockpiling point setting: n=4 (i.e., L=4×2.5=10m), the primary stockpiling point coincides with the reference point, and the coordinates are (10a,10b,0), where a=1,2,...,9 (X0 direction, 10-90m), b=1,2,...,4 (Y0 direction, 10-40m), for a total of 9×4=36 primary stockpiling points.

[0061] Stacking path: Arranged in columns (columns along the X0 direction, perpendicular to the stacker's translation direction Y0), the primary stacking points of each column are connected sequentially, and the beginning and end of the columns are connected to form a curved path, such as the first column (10,10) → (10,20) → (10,30) → (10,40), the end (10,40) connects to the end (20,40) of the second column, the beginning (20,10) of the second column connects to the beginning (30,10) of the third column, and so on, forming a continuous operation path.

[0062] Step 3: Multiple rounds of primary stockpiling Set the initial height h1=2m, the increment h0=1.5m, and the maximum height A=8m.

[0063] Round 1: Starting from (10,10) along the path, pile up to 2m at each primary stockpile point, and complete 36 points in sequence.

[0064] Second round: Update the stockpile height to h1+h0=3.5m, and offset the stockpile position from the initial stockpile point by a certain amount (e.g., X0+2.5m, Y0+2.5m) to avoid overlapping with the position from the previous round. Complete all points in this round in sequence.

[0065] Repeat until the 4th round: height h = 2 + 3 × 1.5 = 6.5m (≤ 8m). Since 2 + 4 × 1.5 = 8m has reached the maximum stacking height A, according to the patent logic, the primary stacking stops after the 4th round. At this time, each primary stacking point is surrounded by staggered stacks in 4 rounds to form an approximately frustum-shaped material pile, reducing the space idle caused by the angle of repose.

[0066] Step 4: Secondary stockpile point screening (solving low-lying areas between adjacent stockpiles) Taking adjacent primary stockpile points P1 (10,10,0) and P2 (20,10,0) as an example: 1. Determine the base point: The midpoint e of the line connecting P1 and P2 is (15, 10, 0). With e as the center,

[0067] Draw a circle containing 12 reference points, including (14,8,0) and (16,12,0).

[0068] 2. Filter the point with the maximum height: Obtain the height Q of the second mapped 3D point corresponding to the reference point inside the circle using LiDAR 7, and filter out the reference point with the maximum height value, assuming it is point f(16,12,0), whose height Q=4.1m.

[0069] 3. Re-filtering: Using the highest point f(16,12,0) as the center, redraw the circular area with the same radius R=7.07m. Obtain the height values ​​Q of all reference points within the new area, and filter again to select the reference point with the largest height value. Assuming the result is still f(16,12,0), determine it as the center point of the area.

[0070] 4. Calculate the accommodating parameter S: Obtain the height values ​​Q1~Q12 of all 12 reference points within the circular accommodating range corresponding to the center point f.

[0071] Q1=4.1m, Q2=3.8m, Q3=3.5m, Q4=3.2m, Q5=3.0m, Q6=3.4m, Q7=3.6m, Q8=3.3m, Q9=2.9m, Q10=3.1m, Q11=3.7m, Q12=2.9m.

[0072] The summation yields 38.5m. Taking a constant K=150, calculate the total height:

[0073] Step 5: Summary of Implementation Results Through primary and secondary stockpiling, the coal storage capacity of this stockpile is increased by about 25% compared to the traditional column stockpiling method. The low-lying areas of 0.5-1.5m in height between adjacent stockpiles, which were originally formed by the angle of repose, are fully utilized. The effective stockpile volume is increased from about 26,000m³ to about 34,000m³, an increase of more than 30%, maximizing the utilization of the stockpile space. The stockpiling path is rationally planned, reducing the idle running and turning waiting time of equipment.

[0074] In addition to the above methods, the present invention can also utilize a stacker system for optimizing stockpile utilization to implement the above methods, including a sensing structure, a positioning structure, a path planning system, and a PLC control system. The sensing structure is used to acquire the status data of the stockpile, the positioning system is used to acquire the position information of the stacker, and the path planning system mainly performs the above-mentioned primary path planning and secondary path planning based on the sensing structure and the positioning system. After the path planning is completed, the PLC control system controls the corresponding drive structure of the stacker to drive to the corresponding target position, thereby realizing the execution of the planned path.

[0075] In addition, level gauges can be used to directly measure the height of each stockpile.

[0076] After the path planning is completed and the current target position is obtained, the PLC control system determines whether the current stacking point position is the target position. If not, the PLC control system controls the boom slewing motor and the trolley traveling motor of the stacker to move the stacking point to the target position. If it is, the stacking operation is carried out at the target position. When the real-time stacking height reaches the originally set stacking height, the stacking at the target position is stopped.

[0077] To achieve the above-mentioned optimized stockpile utilization method, the mechanical structure of the bucket wheel stacker-reclaimer involved in this embodiment is as follows, and please refer to the appendix. Figure 9 (Due to the large size of the pusher, only the approximate installation location of some parts can be marked.)

[0078] The stacker mainly consists of a traveling mechanism 1, a slewing platform 2, a pitching mechanism 3, a boom 4, a bucket wheel mechanism 5, a counterweight 6, and a sensing system integrated thereon. The traveling mechanism 1 is mounted on a track on the stockpile ground and drives the entire stacker to move along the length of the stockpile (i.e., the Y0 axis), enabling large-scale positional transfers within the stockpile. The slewing platform 2 is mounted on the traveling mechanism 1 and can rotate around a vertical axis (Z1 axis). Its function is to support the upper structure (such as the boom and counterweight) and drive its horizontal rotation to adjust the lateral position of the stacking point. The pitching mechanism 3 typically uses a hydraulic cylinder or wire rope winch system, connected between the slewing platform 2 and the boom 4; it drives the boom 4 to pitch around a horizontal axis, thereby changing the pitch angle θ of the boom 4 and adjusting the working height of the bucket wheel mechanism 5. One end of the boom 4 is hinged to the slewing platform 2, serving as the main cantilever beam structure. Its front end supports the bucket wheel mechanism 5, and a conveyor belt is usually installed inside. The bucket wheel mechanism 5 is installed at the free end of the boom 4 and is the core component that directly performs material handling and stacking operations. It continuously digs up materials through the rotating bucket wheel and transports the materials to the designated stacking point via a belt inside the boom. The counterweight 6 is set on the slewing platform 2 and arranged opposite to the boom 4. It is used to balance the overturning moment generated by the boom 4 and the bucket wheel mechanism 5 to ensure the stability of the whole machine.

[0079] The stacker's sensing system is integrated into the aforementioned mechanical structure to provide real-time data for the stacking method. This includes: a lidar 7 fixedly mounted at the end of the boom 4 or near the bucket wheel mechanism 5, used to synchronously scan the surface morphology of the stockpile within the stockpile yard as the boom moves, acquiring real-time 3D point cloud data; an angle encoder 8 installed at the hinge point between the boom 4 and the slewing platform 2, used to accurately measure the real-time pitch angle θ of the boom 4; and a Beidou sensor 9 installed at the stacker's rotation center (usually located on the upper part of the slewing platform 2), used to link with the stockpile yard coordinate system O0-X0Y0Z0, acquiring the stacker's global position coordinates within the stockpile yard in real-time, particularly for determining the translation amount Δy1.

[0080] Through the coordinated operation of the aforementioned mechanical structure and sensing system, the stacker can accurately execute the target position and actions calculated by the path planning system, thereby efficiently and automatically completing the primary and secondary stacking operations.

[0081] like Figures 10 to 12 As shown, this invention also provides a digital control interface for bulk cargo yards based on the aforementioned optimized yard utilization stacking method. This interface integrates functional modules such as digital twin, real-time data monitoring, business statistics, and video linkage, serving as the human-computer interaction hub for achieving fully automated control and visualized management of the stacking method.

[0082] like Figure 10As shown, the main control interface features a 3D digital twin window in the central area. This window is constructed based on the 3D coordinate system O0-X0Y0Z0 of this invention, and renders the stockpile terrain, stockpile shape, boom posture of the bucket wheel stacker-reclaimer, and the position of the traveling mechanism in real time. This window visually displays the spatial distribution formed by the primary stockpile points and secondary stockpile points, allowing operators to verify the execution progress of the curved stockpile path and the forming effect of multiple rounds of staggered stockpiling.

[0083] The right side of the interface features a real-time video monitoring wall, which includes video streams from different perspectives such as the "stacker boom camera" and the "stacker boom overhead camera," creating a virtual-real contrast with the central 3D scene to ensure accurate monitoring of on-site equipment movements even in remote control mode.

[0084] The left and bottom of the interface contain panels displaying equipment status and operating parameters. Top left: Real-time refresh of alarm logs and device operating status (such as "warning" or "normal" status of devices like SR2.4 and SR2.1); Bottom left: Data charts showing recent equipment workload statistics to help determine the efficiency of yard inbound / outbound operations; Bottom: Work order execution list, which records key parameters such as "location", "flow rate" and "actual height" of the current stockpiling task in real time, and communicates with the calculation process of dynamically determining the accommodating parameters between adjacent primary stockpiling points in the claims, ensuring that operators can always grasp the difference between the actual height of the stockpile and the target height.

[0085] like Figure 11 As shown, the system also has a separate data management interface to support fine-grained scheduling and historical data backtracking of the yard. This interface mainly includes: Work Order Information Management Area: Located in the upper middle part, it displays information such as "Work Order Number", "Equipment", "Task Name", and "Materials Yard" for different work orders, making it easy to understand the stacking area of ​​different goods.

[0086] Operational statistics chart area: Located on the right, it uses pie charts, bar charts and other forms to intuitively analyze "inbound and outbound" and "operation volume of each piece of equipment", which makes it easier for yard managers to evaluate the improvement of yard space utilization after completing multiple rounds of primary stacking and secondary stacking point screening.

[0087] like Figure 12 As shown, the main control system has an independent 3D digital twin scene module. The secondary interface of this module's main control interface focuses entirely on the spatial morphology of the storage yard. The figure clearly illustrates the following distinguishing features compared to traditional solutions: Reference point array: Marker lines or points distributed in a grid on the surface of the stacking site, namely, a number of reference points set by the array described in this patent, which are used to guide the data benchmark for subsequent screening of the first mapped three-dimensional points; The system displays the real-time movement of multiple stackers, showing their visible movement paths. Operators can use this scenario to directly determine whether the stackers are stacking materials sequentially according to the stacking path or whether they have accurately moved to the selected secondary stacking points for replenishment operations.

[0088] The digital main control operating interface of this invention is achieved through Figure 10 , Figure 11 Main control interface Figure 12 The visualization of the plant area transforms complex spatial stacking algorithms, such as primary path planning, multi-round staggered stacking, and dynamic selection of secondary stacking points, into intuitive and clear operation guidance and data feedback, thereby maximizing the space utilization of large bulk cargo yards under low intervention and high precision conditions.

[0089] The above embodiments are merely exemplary embodiments of this application and are not intended to limit this application. The scope of protection of this application is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to this application within its substance and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of this application.

Claims

1. A method for stacking materials using a bucket wheel stacker-reclaimer to optimize stockpile utilization, characterized in that, Includes the following steps: Establish a three-dimensional coordinate system O0-X0Y0Z0 for the stockyard, and set several reference points in an array on the X0Y0 plane within the stockyard area based on the three-dimensional coordinate system of the stockyard; The three-dimensional point cloud data of the stockpile is obtained by scanning the stockpile with lidar. The first mapping three-dimensional point with a mapping relationship with the reference point is selected based on the three-dimensional point cloud data, and the coordinate data of each first mapping three-dimensional point is determined. Several primary stockpiling points are arrayed on the X0Y0 plane within the stockyard area, and the primary stockpiling points are connected sequentially to form a stockpiling path; Set the stacking height, and start the first stacking operation from the position near the stockyard entrance and stacker according to the stacking path. After the stacking height is reached, proceed to the next primary stacking point until the last primary stacking point is reached. Update the stacking height, starting from the first primary stacking point and repeating the stacking operation with staggered primary stacking point positions until the maximum stacking height is reached; Based on the coordinate data of the first mapped three-dimensional point, determine the accommodating parameter between at least two adjacent primary stacking points, select the center point corresponding to the maximum accommodating parameter as the secondary stacking point, move the stacker to the secondary stacking point to stack material until the maximum stacking height is reached, and repeat the above steps until all reference points reach the maximum stacking height. Place the lidar on the stacker boom; With the stacker as the origin, construct the stacker coordinate system O1-X1Y1Z1, and the X1OZ1 plane rotates following the rotation of the stacker boom; Construct a radar coordinate system O-XYZ with the lidar as the origin; The coordinates of each first-mapped 3D point in the 3D coordinate system O0-X0Y0Z0 of the stockyard are calculated using the following formula from the 3D point cloud data acquired by the lidar. ； In the formula, R1 is the rotation matrix of the O-XYZ coordinate system relative to the O1-X1Y1Z1 coordinate system. Let O be the translation of the O-XYZ coordinate system relative to the O1-X1Y1Z1 coordinate system. , L is the length of the stacker boom, H is the height of the stacker's rotation center, θ is the pitch angle of the stacker boom, and R2 is the rotation matrix of the O1-X1Y1Z1 coordinate system relative to the O0-X0Y0Z0 coordinate system. Let Δ be the translation of the O1-X1Y1Z1 coordinate system relative to the O0-X0Y0Z0 coordinate system. This is the distance from the center of rotation of the stacker to the origin of the stockyard coordinate system. Based on the coordinate data of the first mapped 3D points, determine the allowable parameters between at least two adjacent primary stockpiling points, and select the center point corresponding to the maximum allowable parameter as the secondary stockpiling point, including the following steps: Establish a line between two adjacent primary stockpiling points, and use the midpoint of the line as the base point; With the base point as the center and R as the radius, draw a circular containment area, obtain the height value Q of the second mapped 3D point corresponding to each reference point within the circular containment area, and filter out the reference point with the largest height value. in, L is the distance between adjacent primary stockpiling points, the second mapped three-dimensional point has a mapping relationship with the corresponding reference point, and Q is the vertical coordinate of the corresponding second mapped three-dimensional point in the stockpile three-dimensional coordinate system O0-X0Y0Z0. Using the reference point with the largest height value as the center and R as the radius, redraw the circular containment area, obtain the height value Q of the second mapped 3D point corresponding to each reference point within the circular containment area, and then select the reference point with the largest height value as the center point. The selected center points are aggregated and their corresponding accommodateable parameters within the circular containment range are calculated. The center point corresponding to the maximum accommodateable parameter is selected as the secondary stacking point.

2. The method for optimizing stockpile utilization using a bucket wheel stacker-reclaimer according to claim 1, characterized in that, Each primary stockpile point coincides with a reference point, and the distances between adjacent primary stockpile points are the same, as are the distances between adjacent reference points. Where L = nl, n is an integer, L is the distance between adjacent primary stacking points, and l is the distance between adjacent reference points.

3. The method for optimizing stockpile utilization using a bucket wheel stacker-reclaimer according to claim 1, characterized in that, The method of connecting the primary stockpiling points to form a stockpiling path includes the following steps: Arrange all primary stacking points in columns along the direction perpendicular to the translation of the stacker; Connect the primary stacking points in each column sequentially; Connect the primary stockpiling point at the end of the first column to the primary stockpiling point at the end of the second column, connect the primary stockpiling point at the beginning of the second column to the primary stockpiling point at the beginning of the third column, and so on, until a continuous curved stockpiling path is formed.

4. The method for optimizing stockpile utilization using a bucket wheel stacker-reclaimer according to claim 3, characterized in that, Before stockpiling, set the stockpiling height h1, and start the first stockpiling from the position near the stockyard entrance and the stockpile machine according to the stockpiling path. After the stockpile reaches the stockpiling height h1, the stockpiling work of the next primary stockpiling point will be carried out until the last primary stockpiling point is reached, thus completing the first round of stockpiling. Update the stockpile height to h1+h0. Start the second round of stockpiling from the position near the stockyard entrance and the stockpile machine according to the stockpiling path. After the stockpile reaches the stockpile height h1+h0, proceed to the next primary stockpile point until the last primary stockpile point is reached, completing the second round of stockpiling. ...and so on, until the Nth round of material stacking is completed, h1+Nh0≤A and h1+(N+1)h0≥A, and the curved material stacking work is stopped after the Nth round of material stacking is completed; Where A is the maximum stacking height, and the stacking position of each round is staggered from the stacking position of the primary stacking point and the stacking position of the previous round.

5. The method for optimizing stockpile utilization using a bucket wheel stacker-reclaimer according to claim 1, characterized in that, The reference point and the first mapped three-dimensional point that has a mapping relationship with it have the same horizontal and vertical coordinates in the three-dimensional coordinate system O0-X0Y0Z0 of the stockyard. The reference point and the second mapped three-dimensional point that has a mapping relationship with it have the same horizontal and vertical coordinates in the three-dimensional coordinate system O0-X0Y0Z0 of the stockyard.

6. The method for optimizing stockpile utilization using a bucket wheel stacker-reclaimer according to claim 1, characterized in that, For one of the center points, obtain all reference points within its corresponding circular containment area and the height values ​​Q1, Q2, Q3, ..., Q of the corresponding second mapped 3D points. n The accommodability parameter S is calculated using the following formula: Where n is the number of reference points within the circular area, and K is a constant.

7. The method for optimizing stockpile utilization using a bucket wheel stacker-reclaimer according to claim 1, characterized in that, After identifying the secondary stockpiling points, materials are stockpiled at these points until they reach their maximum stockpiling height. If the stacker does not completely unload during a single stacking operation, select the nearest center point to continue the stacking process.

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