A method for determining the flatness of a bulkhead surface

Abstract

The application provides a determination method for flatness of a bulkhead surface, comprising the following steps: S1, dividing the bulkhead surface into multiple regions according to preset requirements, and obtaining measured height data of each region; S2, selecting a region to be calculated and setting a region range, and extracting multiple groups of regions in the set region range; S3, determining whether there is a blank region in each group of regions, if there is a blank region in each group of regions, returning the flatness data of the region to be calculated as 0, if there is no blank region in each group of regions, or only some groups of regions have blank regions, then removing the groups with blank regions, and using formula (2): Δ = |B-(A+C) / 2| to calculate the difference between each straightness data and the measured height data of the region to be calculated, and screening out the maximum value in the difference as the flatness data of the region to be calculated; and S4, repeating S2-S3 until the flatness data of all regions on the bulkhead surface is calculated. The method greatly reduces the calculation amount and makes up for the limitations of the traditional method.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bulkhead surface flatness calculation, in particular to a determination method of bulkhead surface flatness. BACKGROUND

[0002] The fuel tank of a large container ship and the liquid cargo tank of a large LNG ship both adopt a membrane type containment system. Based on the installation characteristics of the membrane type containment system, the flatness of each bulkhead needs to be strictly controlled during the segmented manufacturing and general assembly stages of the ship. That is, the flatness of each bulkhead needs to be comprehensively measured and evaluated after the tank is formed and before the containment system is installed, in order to meet the installation requirements of the membrane type containment system.

[0003] The traditional method is to measure the actual flatness with a simulation caliper to determine whether the local bulkhead surface needs to be modified. This traditional flatness measurement method is time-consuming, has a high error rate, and has the problems of low efficiency and high operation difficulty. In the prior art, there is also a flatness measurement method that measures the height data of the actual position of the bulkhead surface as flatness data, which can be seen in the application patent with application number 202111272229.7. However, this flatness determination method that uses the height data of the actual position as flatness data has the problem of being unable to quickly and accurately identify risk points.

[0004] Therefore, there is an urgent need for a determination method of bulkhead surface flatness. SUMMARY

[0005] The purpose of the embodiments of the present application is to provide a determination method of bulkhead surface flatness, which solves the problems of low efficiency and high operation difficulty of the flatness measurement method, and the problem of being unable to quickly and accurately identify risk points in the prior art flatness determination method that uses the height data of the actual position as flatness data.

[0006] The present application provides a determination method of bulkhead surface flatness, comprising:

[0007] S1, dividing the bulkhead surface into multiple regions according to predetermined requirements, and obtaining the measured height data of each region;

[0008] S2, selecting a region to be calculated and setting a region range, extracting multiple groups of regions within the set region range, each group of regions including two regions arranged on both sides of the region to be calculated;

[0009]

[0009] S3, determining whether there is a blank region in the multiple groups of regions,

[0010] If there is a blank region in each group of regions, it is determined that the region to be calculated does not have flatness data;

[0011] If there are no blank areas in multiple groups of regions, or only some groups of regions have blank areas, then remove the groups with blank areas and use formula (1): M=(A+C) / 2 to calculate the straightness data of each group of regions; then use formula (2): △=∣B–(A+C) / 2∣ to calculate the difference between each straightness data and the measured height data of the region to be calculated, and select the maximum value of the difference as the flatness data of the region to be calculated, where: M is the straightness data of each group of regions, A and C are the measured height data of the two regions in each group of regions, △ is the difference, and B is the measured height data of the region to be calculated;

[0012] S4. Repeat S2-S3 until the flatness data of all areas on the bulkhead are calculated.

[0013] In one implementation, step S1, dividing the bulkhead into multiple regions according to preset requirements and obtaining measured height data for each region, includes:

[0014] A single bulkhead is divided into multiple grid regions in a 1M*1M square grid. The measured height data of a predetermined grid region of the bulkhead is set to 0. Each region of the bulkhead is scanned and measured using a scanner. The coplanarity data of each of the remaining grid regions relative to the predetermined grid region set to 0 is obtained. The coplanarity data is used as the measured height data of each of the remaining grid regions.

[0015] In one implementation, step S2, defining the area range, includes extracting multiple groups of areas within the defined area range, which comprises:

[0016] Centered on the area to be calculated, the nine-square grid containing the area to be calculated is defined as the area range. The areas along the four lines of the cross shape of the nine-square grid are extracted, and the two areas at both ends of each line are taken as a group of areas.

[0017] In one implementation, in S3, the existence of blank areas in each group of areas includes four blank cells in the 3x3 grid containing the area to be calculated and five blank cells in the 3x3 grid containing the area to be calculated.

[0018] In one implementation, in S3, the existence of blank areas in only a portion of the group area includes one blank cell in the 3x3 grid area where the area to be calculated is located, two blank cells in the 3x3 grid where the area to be calculated is located, and three blank cells in the 3x3 grid where the area to be calculated is located.

[0019] In one implementation, after S1 and before S2, the method further includes importing the measured height data of each area into an Excel spreadsheet, and creating multiple table areas in the Excel spreadsheet with the same boundary size as the multiple areas of the bulkhead, and setting a formula (2) for calculating the flatness in each table area.

[0020] In one embodiment, after calculating the flatness data for all areas of the bulkhead surface, the method further includes:

[0021] In an Excel table area, set conditional formatting and define the fill color level format. Set it so that the larger the flatness data, the darker the fill color of the cells in the table area.

[0022] In one implementation, after step S4, the method further includes identifying problem areas based on the flatness data, further examining the straightness data of multiple groups of areas within the set area where the problem area is located, and formulating a corresponding flatness modification plan based on the magnitude and direction of the straightness data deviation.

[0023] The method for determining the flatness of the bulkhead surface in this application has the following advantages:

[0024] Compared to the traditional method of manually measuring flatness using analog calipers, this application calculates local flatness data based on the height data of the measured location using a nine-square grid. A single formula encompassing all boundaries and internal conditions is used to calculate the local flatness data. This method can be extended to fuel tanks of large container ships and cargo tanks of large LNG carriers, significantly reducing the computational workload and overcoming the limitations of traditional methods. Furthermore, this method improves the efficiency and accuracy of local flatness calculations. Local flatness data allows for the rapid and accurate identification of risk points, addressing the shortcomings of existing technologies that cannot quickly and accurately identify risk points. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic diagram illustrating the structure of a fuel tank wall according to an embodiment of this application;

[0027] Figure 2 This is an unfolded plan view of a fuel tank wall according to an embodiment of this application;

[0028] Figure 3The measured height data of a bulkhead surface according to an embodiment of the present application;

[0029] Figure 4 The schematic diagram of a nine-square grid of a region to be calculated according to an embodiment of the present application;

[0030] Figure 5 The structural schematic diagram of a rice-shaped line of a nine-square grid according to an embodiment of the present application;

[0031] Figure 6 The measured height data of a nine-square grid according to an embodiment of the present application;

[0032] Figure 7 The layout schematic diagram of a plurality of regions according to an embodiment of the present application;

[0033] Figure 8 The layout schematic diagram of a plurality of regions according to an embodiment of the present application; Figure 1 ;

[0034] Figure 9 The layout schematic diagram of a plurality of regions according to an embodiment of the present application; Figure 2 ;

[0035] Figure 10 The layout schematic diagram of a plurality of regions according to an embodiment of the present application;

[0036] Figure 11 The layout schematic diagram of a plurality of regions according to an embodiment of the present application;

[0037] Figure 12 The schematic diagram of a straightness calculation method according to an embodiment of the present application;

[0038] Figure 13 The flatness data of all regions of a bulkhead surface according to an embodiment of the present application;

[0039] Figure 14 The schematic diagram of searching for straightness data according to bulkhead surface flatness data according to an embodiment of the present application.

[0040] 100, first bulkhead surface; 200, second bulkhead surface; 300, third bulkhead surface; 400, fourth bulkhead surface; 500, fifth bulkhead surface; 600, sixth bulkhead surface; 700, seventh bulkhead surface; 800, eighth bulkhead surface; 900, ninth bulkhead surface; 1000, tenth bulkhead surface. DETAILED DESCRIPTION

[0041] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0042] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application.

[0043] The present application provides a method for determining the flatness of a bulkhead surface. Referring to Figures 1-13 The method comprises the following steps:

[0044] S1, dividing the bulkhead surface into multiple regions according to predetermined requirements, and obtaining measured height data of each region;

[0045] Take the fuel tank as an example. Referring to Figure 1 and Figure 2 The fuel tank forms 10 bulkhead surfaces, including 2 octagonal bulkhead surfaces (the second bulkhead surface 200 and the fourth bulkhead surface 400) at the bow and stern, and 8 quadrilateral bulkhead surfaces (the first bulkhead surface 100, the third bulkhead surface 300, the fifth bulkhead surface 500, the sixth bulkhead surface 600, the seventh bulkhead surface 700, the eighth bulkhead surface 800, the ninth bulkhead surface 900 and the tenth bulkhead surface 1000). After the cargo tank is cleaned, a scanner is used to scan and measure the inner shell, and the single surface is gridded to take points according to 1M*1M square, to generate measured height data of each bulkhead surface. Referring to Figure 3 The measured height data of one of the octagonal bulkhead surfaces has nearly 900 points. The specific process is that XYZ three-dimensional coordinates are used to define each region on the bulkhead surface, wherein Z / Y is the coordinate setting value of each region on the bulkhead surface, and X is the flatness data. In an embodiment, the X / Z / Y in the region coordinate of the lower right corner of the octagonal bulkhead surface is set to 0 / 0 / 0, and the flatness data of the remaining each grid region relative to the region of the lower right corner set to 0 is obtained, which is the measured height data of the remaining each grid region.

[0046] S2, selecting a region to be calculated and setting a region range, extracting multiple groups of regions in the set region range, each group of regions including two regions arranged on both sides of the region to be calculated;

[0047] Continuing with the example of the fuel tank, in one possible implementation, the region to be calculated (0,0) is centered on the area to be shifted upwards, downwards, leftwards, rightwards, upper left, lower left, upper right, and lower right by one unit, forming a nine-square grid area. See details... Figure 4 See next. Figure 5 and Figure 6 Using the center of the 3x3 grid as a reference, four lines in a star shape are drawn in the Y, X, and two diagonal directions. Each line includes measured height data for three regions. The two regions at the ends of each line are considered as one group, and multiple groups of regions are extracted from the four lines in the star shape of the 3x3 grid. See [link / reference] Figures 4-6 The coordinates of the region to be calculated are set to (0, 0). The coordinates of the nine-square grid formed by offsetting one unit each upwards, downwards, leftwards, rightwards, upper left, lower left, upper right, and lower right from the region to be calculated are (-1, -1), (-1, 0), (-1, 1), (0, -1), (0, 1), (1, -1), (1, 0), and (1, 1). The measured height data value of the region offset to (-1, -1) is set as 'a', and the value of the region offset to (-1, 0) is set as 'a'. The measured height data for region (-1,1) is b, for region (0,-1) it is c, for region (0,-1) it is d, for region (0,0) it is e, for region (0,1) it is f, for region (1,-1) it is g, for region (1,0) it is h, and for region (1,1) it is k. See also... Figure 4 and Figure 7 The rice-shaped pattern includes four groups of regions: (-1,-1) and (1,1) as one group, (-1,0) and (1,0) as one group, (-1,1) and (1,-1) as one group, and (0,-1) and (0,1) as one group.

[0048] S3. Determine whether there are blank areas within multiple groups of regions.

[0049] If there are blank areas in each group of regions, see Figures 8-9 If no flatness data is found in the area to be calculated, then the flatness data for the area to be calculated is empty.

[0050] If there are no blank areas in multiple groups of regions (see...) Figure 10 ), or only some of the group regions contain blank areas (see Figure 11) then remove the group with blank area, and calculate the straightness data of each group by formula (1): M = (A + C) / 2; then calculate the difference between each straightness data and the measured height data of the region to be calculated by formula (2): Δ = |B - (A + C) / 2| (see Figure 12 ), and select the maximum value in the difference as the flatness data of the region to be calculated, wherein: M is the straightness data of each group, A and C are the measured height data of two regions in each group, Δ is the difference, and B is the measured height data of the region to be calculated;

[0051] According to the set region range, extract multiple groups of regions from Figure 3 If there is a blank area in each group of regions, see Figures 8-9 , that is, it is impossible to form any line in Figure 7 , return that the region to be calculated does not have flatness data, that is, the result is empty.

[0052] See Figure 11 , if only part of the group regions have blank areas, then remove the groups with blank areas, such as Figure 11 ①, (-1, 0), (-1, -1) and (0, -1) regions are all empty, then return the result of the flatness data of the region to be calculated as |e - (c + g) / 2|. For example Figure 11 -②, (1, 0), (1, -1) and (0, -1) regions are all empty, then return the result of the flatness data of the region to be calculated as |e - (a + k) / 2|. For example Figure 11 -③, if (0, 1), (-1, 1) and (-1, 0) regions are all empty, then return the result of the flatness data of the region to be calculated as |e - (a + k) / 2|. For example Figure 11 -④, if (0, 1), (1, 1) and (1, 0) regions are all empty, then return the result of the flatness data of the region to be calculated as |e - (c + g) / 2|. For example Figure 11 -⑤, Figure 11 -⑥, if (0, -1) or (0, 1) region is empty, then return the result of the flatness data of the region to be calculated as |e - (b + h) / 2|. For example Figure 11 -⑦, Figure 10 -⑧), if (-1, 0) or (1, 0) unit region is empty, then return the result of the flatness data of the region to be calculated as |e - (d + f) / 2|.

[0053] If none of the above cases, see Figure 13 , that is, there is no blank area in multiple groups of regions, then return the result of the flatness data of the region to be calculated as the maximum value of |e - (c + g) / 2|, |e - (a + k) / 2|, |e - (b + h) / 2| and |e - (d + f) / 2|.

[0054] S4, repeating S2-S3 until the flatness data of all areas on the bulkhead surface is calculated (see Figure 8 ).

[0055] In the above implementation process, by processing the original measured height data, the straightness data of multiple groups of areas is calculated by the nine-square grid, and the flatness is calculated by the straightness, which greatly reduces the calculation amount, reduces the error rate of human measurement, makes up for the limitations of the prior art, and improves the efficiency and accuracy of the calculation of the local flatness.

[0056] In one embodiment, in S3, there are blank areas in each group of areas, including four blank squares in the nine-square grid where the area to be calculated is located (see Figure 9 ) and five blank squares in the nine-square grid area where the area to be calculated is located (see Figure 11 ).

[0057] In one embodiment, in S3, there are blank areas in only part of the group areas, including one blank square in the nine-square grid where the area to be calculated is located, two blank squares in the nine-square grid area where the area to be calculated is located, and three blank squares in the nine-square grid area where the area to be calculated is located (see Figure 13 ).

[0058] In one embodiment, after S1 and before S2, it further includes importing the measured height data of each area into an Excel table, see Figure 13 , and establishing a plurality of table areas with the same boundary size as the plurality of areas of the bulkhead surface in the Excel table, and setting formula (2) for calculating flatness in each table area. The nine-square grid data is calculated by using Excel formula, and all boundaries and internal conditions are included in one formula, and the process of calculating the local flatness is faster.

[0059] In one embodiment, after calculating the flatness data of all areas on the bulkhead surface, it further includes:

[0060] Setting conditional formatting in the table area of Excel, defining the fill color step format, and setting it to the larger the flatness data, the darker the fill color of the cell in the table area, see Figure 3 , the red and green color steps can be selected, and the larger the flatness value in the cell, the darker the red fill color of the cell. Further, the problem area can be quickly viewed.

[0061] In one embodiment, after S4, it further includes finding the problem area with larger data according to the flatness data, see Figure 13 , Figure 14 and Figure 13 . Figure 3The number 21, with Z / Y coordinates (3000, 44000), has the darkest color. Figure 3 Further examine the straightness data of multiple sets of areas within the defined area where the problem area is located. Figure 14 (The nine-square grid within the thick frame), see [link / reference] Figure 14 Extract the straightness data, and formulate corresponding flatness modification plans based on the magnitude and direction of the straightness data deviation. Specifically, further examine the corresponding nine-square grid values ​​in the same-surface data table; the straightness data deviation in the Y direction is 5.5 (see...). Figure 14 -①), straightness data deviation in the X direction is 16 (see ①). Figure 14 -②), the straightness data deviation from the upper left to the lower right diagonal upward is 10.5 (see...). Figure 14 -③), the straightness data deviation from the upper right to the lower left diagonal upward is 21 (see...). ​ -④) Further, based on the magnitude and direction of the data deviation, formulate a modification plan.

[0062] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for determining the flatness of a cabin wall surface, characterized in that, Including: S1. Divide the bulkhead surface into multiple regions according to preset requirements, and obtain the measured height data of each region; S2. Select the region to be calculated and set the region range. Extract multiple groups of regions within the set region range. Each group of regions includes two regions respectively arranged on both sides of the region to be calculated. Among them, the set region range, extracting multiple groups of regions within the set region range includes taking the region to be calculated as the center, setting the nine-square grid where the region to be calculated is located as the region range, and extracting the regions on the four lines of the cross shape of the nine-square grid. The two regions at both ends of each line are used as a group of regions; S3. Determine whether there are blank regions in multiple groups of regions; If there are blank regions in each group of regions, it is returned that there is no flatness data for the region to be calculated; If there are no blank regions in multiple groups of regions, or there are blank regions only in some groups of regions, after removing the groups with blank regions, use formula (1): M = (A + C) / 2 to calculate the straightness data of each group of regions; then use formula (2): △ = ∣B–(A + C) / 2∣ to calculate the difference between each straightness data and the measured height data of the region to be calculated, and screen out the maximum value in the differences as the flatness data of the region to be calculated, where: M is the straightness data of each group of regions, A and C are the measured height data of the two regions in each group of regions, △ is the difference, and B is the measured height data of the region to be calculated. Among them, the situation that there are blank regions in each group of regions includes that there are four blank cells in the nine-square grid where the region to be calculated is located and there are five blank cells in the nine-square grid where the region to be calculated is located; the situation that there are blank regions only in some groups of regions includes that there is one blank cell in the nine-square grid area where the region to be calculated is located, there are two blank cells in the nine-square grid where the region to be calculated is located, and there are three blank cells in the nine-square grid where the region to be calculated is located; S4. Repeat S2 - S3 until the flatness data of all regions on the bulkhead surface is calculated.

2. The method for determining the flatness of the bulkhead surface according to claim 1, characterized in that, In S1, the step of dividing the bulkhead surface into multiple regions according to preset requirements and obtaining the measured height data of each region includes: Grid-divide a single bulkhead surface into multiple grid regions with a side length of 1M * 1M. Set the measured height data of a predetermined grid region of the bulkhead surface to 0. Use a scanner to scan and measure each region of the bulkhead surface, and obtain the coplanarity data of the remaining each grid region relative to the predetermined grid region set to 0. Take the coplanarity data as the measured height data of the remaining each grid region.

3. The method for determining the flatness of the bulkhead surface according to claim 1, characterized in that, After S1 and before S2, it further includes importing the measured height data of each obtained region into an Excel table, and creating multiple table regions in the Excel table with the same boundary size as the multiple regions of the bulkhead surface, and setting formula (2) for calculating flatness in each table region.

4. The method for determining the flatness of the bulkhead surface according to claim 3, characterized in that, After calculating the flatness data of all regions on the bulkhead surface, it further includes: Set conditional formatting in the table region of Excel, define the fill color scale format, and set it so that the larger the flatness data, the darker the fill color of the cells in the table region.

5. The method for determining the flatness of the bulkhead surface according to claim 1, characterized in that, Following S4, the process further includes identifying problem areas based on the flatness data, further examining the straightness data of multiple groups of areas within the defined area where the problem area is located, and formulating corresponding flatness modification plans based on the magnitude and direction of the straightness data deviation.

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