Frame identification method for assembled open block structures in ships

Abstract

This invention provides a frame identification method for mid-assembly open block structures in ships, comprising the following steps: Step S1) Obtain the shape data of all plates from the design data; Step S2) Analyze the shape data of all plates to determine the workpiece base surface, and use the workpiece base surface as the reference surface for frame identification; Step S3) Determine the vertical partitions formed by the longitudinal girder and ribs through the base surface, and determine the dividing lines in the X and Y directions based on the projection outline of the upright plate on the base surface. The dividing lines intersect and surround to form a preliminary frame border; Step S4) Calculate the precise frame border based on the upright plate type, lifting direction, and thickness. This invention automatically identifies the frame of mid-assembly open block structures by analyzing and processing plate data, which is beneficial for providing data support for dividing welding areas during offline planning.

Description

Technical Field

[0001] This invention relates to the field of robotic welding technology, and more particularly to a frame identification method for assembling open block structures in ships. Background Technology

[0002] When performing offline path planning for assembled components in a ship, it is necessary to group the welds on the components. For open block structures, since the ribs and longitudinal girder are usually higher than other parts on the bottom plate, the ribs and longitudinal girder can be used as separators to form a frame. This frame serves as the basis for weld grouping. In an offline environment, a model-based method for frame division is needed. The patent "A Positioning Method and System for Large Steel Structures" uses a spatial rectangle fitting method based on point clouds to obtain the assembly structure. In ship structural design, the types of assembly parts are determined. Therefore, this patent can extract the required part information from the design data without the need for point cloud preprocessing. Summary of the Invention

[0003] The purpose of this invention is to provide a frame identification method for assembling open block structures in ships.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows:

[0005] A method for identifying frames in shipboard open block structures, characterized by the following steps:

[0006] Step S1) Obtain the shape data of all boards from the design data;

[0007] Step S2) Analyze the shape data of all plates, determine the workpiece base surface, and use the workpiece base surface as the reference surface for frame identification;

[0008] Step S3) Determine the vertical partition formed by the longitudinal girder and rib plate through the base surface. Based on the projection outline of the vertical plate on the base surface, determine the dividing lines in the X and Y directions. The dividing lines intersect and surround to form the preliminary frame border.

[0009] Step S4) Calculate the precise frame border based on the type of upright panel, the direction of lifting, and the thickness.

[0010] Furthermore, in step S2, the method for determining the workpiece datum surface includes the following steps:

[0011] Step S21) Calculate the projection surfaces formed by the projection points of the contour points of each plate in the X, Y, and Z directions respectively;

[0012] Step S22) Determine the bounding projection rectangle formed by the projection points in the X, Y, and Z directions, and calculate the area of ​​the rectangle;

[0013] Step S23) Compare the areas of the rectangles enclosing the X, Y, and Z directions, and take the projection direction of the largest area as the base plane projection direction;

[0014] Step S24) Obtain the base surface of the entire workpiece according to the projection direction of the base surface.

[0015] Furthermore, in step S3, the determination of the separator line includes the following steps:

[0016] Step S31) Determine that projection lines with similar X or Y coordinates are line segments on the same straight line and perform two-dimensional parallelism fitting.

[0017] Step S32) Combine the base rectangle and sort the two-dimensional horizontal and vertical fitted lines according to top and bottom, left and right.

[0018] Step S33) Initially divide the cells without thickness information to obtain the frame border.

[0019] Furthermore, in step S31, the method for determining the same straight line includes the following steps:

[0020] Step S311) Obtain all the vertical plates parallel to the X-axis direction, denoted as P. For each plate in P, calculate the coordinate difference of the vertices in the Y direction, i.e. the plate thickness value.

[0021] Step S312) Calculate the maximum plate thickness value and denot it as T. m ,

[0022] T m =Max(px) r -px l ), p∈P;

[0023] Step S313) List the plates on the same straight line as L p Iterate through P, and denot each obtained plate as p. The coordinate of p in the X+ direction is p. xr ;

[0024] Step S314) Traverse L p Each time a plate is obtained, it is denoted as p', and the coordinate of p' in the X+ direction is p. x’r ;

[0025] Step S315) Calculate p xr With p x’r The difference, if the difference is less than T m This indicates that p and L p If the plates in the diagram belong to the same straight line, and the difference is greater than or equal to T... m This indicates that p and L p The plates in the diagram do not belong to the same straight line.

[0026] Furthermore, in step S315, a parameter S(p) is defined, where S(p) = 1 indicates that p is related to L. p The plates in the diagram belong to the same straight line, and S(p) = -1 indicates that p and L are on the same straight line. p The plates in the diagram are not on the same straight line.

[0027]

[0028] Furthermore, in step S4, calculating the precise frame border includes the following steps:

[0029] Step S41) Obtain the type and stretching direction of the vertical plate through the design data, and calculate the thickness of the vertical plate;

[0030] Step S42) Offset the original contour points according to the stretching direction and thickness to obtain four new vertices;

[0031] Step S43) Combine the four vertices of the original outline, take the four vertices that form the rectangle with the largest area, and the straight line obtained by connecting these four vertices is the precise border line.

[0032] This invention utilizes the analysis and processing of plate data to automatically identify the framework of the open block structure in the middle assembly, providing data support for the division of welding areas during offline planning. Attached Figure Description

[0033] Figure 1 This is a flowchart of the present invention;

[0034] Figure 2 This is a flowchart of step S2 of the present invention;

[0035] Figure 3 This is a flowchart of step S3 of the present invention;

[0036] Figure 4 This is a flowchart of step S31 of the present invention;

[0037] Figure 5 This is a flowchart of step S4 of the present invention;

[0038] Figure 6 This is a schematic diagram of the workpiece model of the present invention;

[0039] Figure 7 This is a schematic diagram illustrating the effect of the frame border division in this invention;

[0040] Figure 8 This is a schematic diagram comparing the border lines when there is a difference in plate thickness in this invention.

[0041] Figure label:

[0042] 1 to 8 boards;

[0043] 9. Base plate. Detailed Implementation

[0044] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0045] This invention discloses a frame identification method for assembled open block structures in ships, such as... Figure 1 As shown, the method includes the following steps:

[0046] Step S1) Obtain the shape data of all boards from the design data;

[0047] Step S2) Determine the workpiece base surface by analyzing the shape data of all plates. The workpiece base surface will be used as the reference surface for frame identification.

[0048] Step S3) Determine the vertical partition formed by the longitudinal girder and rib plate through the base surface, and determine the dividing lines in the X and Y directions based on the projection outline of the vertical plate on the base surface. The intersection and encirclement of the dividing lines constitute the preliminary frame frame.

[0049] Step S4) Consider the type of uprights, the direction of stretching, and the thickness to calculate the precise frame border.

[0050] like Figure 2 As shown, the method for determining the workpiece datum surface in step S2 includes the following steps:

[0051] Step S21) Calculate the projection surfaces formed by the projection points of the contour points of each plate in the X, Y, and Z directions respectively;

[0052] Step S22) Determine the bounding projection rectangle formed by the projection points in the X, Y, and Z directions, and calculate the area of ​​the rectangle;

[0053] Step S23) Compare the areas of the rectangles enclosing the X, Y, and Z directions, and take the projection direction of the largest area as the base plane projection direction;

[0054] Step S24) Obtain the base surface of the entire workpiece according to the projection direction of the base surface.

[0055] like Figure 3 As shown, in step S3, the determination of the separator line includes the following steps:

[0056] Step S31) Determine that projection lines with similar X or Y coordinates are line segments on the same straight line and perform two-dimensional parallelism fitting.

[0057] Step S32) Combine the base rectangle and sort the two-dimensional horizontal and vertical fitted lines according to top and bottom, left and right.

[0058] Step S33) Initially divide the cells without thickness information to obtain the frame border.

[0059] like Figure 4 As shown, the method for determining the same straight line in step S31 includes the following steps:

[0060] Step S311) Obtain all the vertical plates parallel to the X-axis direction, denoted as P. For each plate in P, calculate the coordinate difference of the vertices in the Y direction, i.e. the plate thickness value.

[0061] Step S312) Calculate the maximum plate thickness value and denot it as T. m ,

[0062] T m =Max(px) r -px l ), p∈P;

[0063] Step S313) List the plates on the same straight line as L p Iterate through P, and denot each obtained plate as p. The coordinate of p in the X+ direction is p. xr ;

[0064] Step S314) Traverse L p Each time a plate is obtained, it is denoted as p', and the coordinate of p' in the X+ direction is p. x’r ;

[0065] Step S315) Calculate p xr With p x’r The difference, if the difference is less than T m This indicates that p and L p If the plates in the diagram belong to the same straight line, and the difference is greater than or equal to T... m This indicates that p and L p The plates in the diagram do not belong to the same straight line.

[0066] Furthermore, in step S315, a parameter S(p) is defined, where S(p) = 1 indicates that p is related to L. p The plates in the diagram belong to the same straight line, and S(p) = -1 indicates that p and L are on the same straight line. p The plates in the diagram are not on the same straight line.

[0067]

[0068] like Figure 5 As shown, in step S4, calculating the precise frame border includes the following steps:

[0069] Step S41) Obtain the type and stretching direction of the vertical plate through the design data, and calculate the thickness of the vertical plate;

[0070] Step S42) Offset the original contour points according to the stretching direction and thickness to obtain four new vertices;

[0071] Step S43) Combine the four vertices of the original outline, take the four vertices that form the rectangle with the largest area, and the straight line obtained by connecting these four vertices is the precise border line.

[0072] The identification method of the present invention includes the following steps in its specific implementation:

[0073] (1) Read the workpiece design data from the API interface of the ship design software. The design data is divided into a parts list, a weld list, and assembly information. Taking a certain part as an example, its geometric structure is as follows: Figure 6 As shown; the thickness of its base plate is 30mm, and the thickness of each upright plate is 20mm; a total of 9 plates were selected according to the classification attributes of the parts, and their shape data were obtained respectively;

[0074] (2) Calculation of the X, Y and Z projection planes shows that the projection area of ​​plate 9 is the largest. Plate 9 is defined as the substrate. The Z axis direction is determined according to the projection of the X and Y directions. The plane in the Z+ direction is selected as the base plane.

[0075] (3) Traversing plates 1 to 8, it can be seen that plates 1 to 6 are longitudinal girder plates, and plates 7 to 8 are rib plates; among them, plates 1 to 3 are on the same straight line, and plates 4 to 6 are on the same straight line, thus dividing this workpiece into 9 independent areas;

[0076] (4) Determine the actual border lines based on the projections of plates 1-8 onto the base surface to obtain the workpiece frame. See [reference needed]. Figure 7 and Figure 8 .

[0077] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for identifying frames in shipboard open block structures, characterized in that, The method includes the following steps: Step S1) Obtain the shape data of all boards from the design data; Step S2) Determine the workpiece base surface by analyzing the shape data of all plates. The workpiece base surface will be used as the reference surface for frame identification. Step S3) Determine the vertical partition formed by the longitudinal girder and rib plate through the base surface, and determine the dividing lines in the X and Y directions according to the projection outline of the upright plate on the base surface. The dividing lines intersect and surround to initially form the frame frame. The method for determining the dividing line is to identify the projection lines with similar X or Y coordinates as line segments on the same straight line, perform two-dimensional parallelism fitting, combine the base rectangle, and sort the two-dimensional horizontal and vertical fitted lines according to top and bottom and left and right. The preliminary division of the grid without thickness information is the frame border. The method for determining if a line is the same is as follows: obtain all the vertical plates parallel to the X-axis, denoted as P; for each plate in P, calculate the coordinate difference of its vertices in the Y-direction, i.e., the plate thickness; and calculate the maximum plate thickness, denoted as T. m The plates on the same straight line are denoted as L. p Let p be the board obtained in each iteration of P, and let p's coordinate in the X+ direction be px. r traverse L p Let p' be the plate obtained each time, and let p'' be the coordinate of px' in the X+ direction. r Calculated using Equation 2, S(p)=1 indicates that p and L p The plates in the diagram must be on the same straight line; otherwise, they must not. (1) (2) Step S4) Consider the type of uprights, the direction of stretching, and the thickness, and calculate the precise frame border.

2. The frame identification method for assembled open block structures in ships according to claim 1, characterized in that, In step S2, the base surface determination method is to calculate the projection surface formed by the projection points of the contour points of each plate in the X, Y, and Z directions, determine the outer projection rectangle formed by the projection points in the X, Y, and Z directions, calculate the area of ​​the rectangle, compare the size of the outer rectangles in the X, Y, and Z directions, take the projection direction of the largest area as the base surface projection direction, and obtain the base surface of the entire workpiece according to the base surface projection direction.

3. The frame identification method for assembled open block structures in ships according to claim 1, characterized in that, In step S4, the method for calculating the precise frame border is to obtain the type and stretching direction of the upright plate through the design data, calculate the thickness of the upright plate, and obtain 4 new vertices by offsetting the original contour points according to the stretching direction and thickness. Combine the 4 vertices of the original contour and take the 4 vertices that form the rectangle with the largest area. The straight line obtained by connecting these 4 vertices is the precise border line.

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