CN115033829B - Object plane type identification method based on two-dimensional point set - Google Patents
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Abstract
The invention provides an object plane type identification method based on a two-dimensional point set, which comprises the following steps: calculating the Y-direction length and the Z-direction length of the obtained object plane; calculating and obtaining an object plane YZ ratio, and judging whether the object plane YZ coordinates are interchanged or not according to the object plane YZ ratio; meshing any object plane; calculating and obtaining a number array of central points of the unit length in the Z direction; extracting central point coordinates in all Z-direction segments meeting the requirements of |s j-m|＜szm, j=1, 2,., and fitting according to the central point coordinates to obtain a fitting straight line; calculating and obtaining the slenderness ratio coefficient of the object plane; repeating the steps, and calculating and obtaining the distance variance coefficient and object plane variance coefficient of each object plane; and judging whether any object plane belongs to the wing object plane or the body object plane according to the object plane variance coefficient and the object plane slenderness ratio coefficient of any object plane. By applying the technical scheme of the invention, the technical problems that the load calculation efficiency is low, the output results are not uniform and the comparison is not facilitated due to the fact that different types of object planes are manually identified and segmented in the prior art are solved.
Description
Technical Field
The invention relates to the technical field of loads, in particular to an object plane type identification method based on a two-dimensional point set.
Background
The load profession is an upstream profession of the intensity profession, and the accuracy and timeliness of the load data have serious influence on the design of the aircraft. According to the load characteristics, the plane of the aircraft can be divided into a plane mainly based on lifting force and a body plane mainly based on inertial force, and different load analysis methods are needed for different types of planes.
As aircraft designs move toward high speed, high mobility, aircraft multi-stage connection designs continue to increase, with ever increasing types and numbers of object planes, more complex layout forms, and shape and installation angles exhibiting a variety of features. The load design also faces the problems of more complex calculation working conditions, larger calculation modes, more complicated flow, higher requirements on design accuracy and analysis period and the like.
Aiming at load calculation of different types of object planes, the traditional method can only solve the object planes of different types independently, usually requires manual identification and segmentation, and has low efficiency, non-uniform output results and unfavorable comparison.
Disclosure of Invention
The invention provides an object plane type identification method based on a two-dimensional point set, which can solve the technical problems of low load calculation efficiency, non-uniform output result and unfavorable comparison caused by manual identification and segmentation of different object planes in the prior art.
The invention provides an object plane type identification method based on a two-dimensional point set, which comprises the following steps: step one, obtaining two-dimensional coordinate points of all nodes on any object plane, and calculating the Y-direction length and the Z-direction length of the obtained object plane; calculating and obtaining an object plane YZ ratio according to the Y-direction length and the Z-direction length of the object plane, and judging whether to exchange the coordinates of the object plane YZ according to the object plane YZ ratio; step three, any object plane is subjected to grid division to construct n multiplied by n grid blocks; mapping all nodes of any object plane into each grid partition, marking the center point of the grid with the object plane nodes, and calculating to obtain a Z-direction unit length center point number array S 1,S2,…,Sn; step five, calculating and obtaining a central point median S ZM in a central point number array S 1,S2,…,Sn of a Z-direction unit length, judging whether the number of central points in each section of the Z-direction unit length meets |s j-m|＜szm, j=1, 2, n, extracting central point coordinates in all Z-direction sections meeting the requirements of |s j-m|＜szm, j=1, 2, n, and fitting to obtain a fitting straight line according to the central point coordinates in all Z-direction sections meeting the requirements of |s j-m|＜szm, j=1, 2, m=1-3; step six, calculating and obtaining a distance variance coefficient and a distance maximum value according to the distances from all the nodes on any object plane to the fitting straight line, and calculating and obtaining an object plane slenderness ratio coefficient according to the distance variance and the distance maximum value; step seven, repeating the step one to the step six for a plurality of object planes, calculating and obtaining the distance variance coefficient and the object plane slenderness ratio coefficient of each object plane, and calculating and obtaining the object plane variance coefficient of each object plane according to the distance variance coefficient of each object plane; and step eight, comparing the object plane variance coefficient of any object plane with a set object plane variance coefficient threshold value, and comparing the slenderness ratio coefficient of any object plane with a set object plane slenderness ratio coefficient threshold value to judge that any object plane belongs to the wing object plane or the body object plane.
Further, the first step specifically includes: acquiring two-dimensional coordinate points of all nodes on any object plane, acquiring a Y-coordinate maximum value and a Y-coordinate minimum value of the object plane, and calculating the Y-direction length of the object plane according to the Y-coordinate maximum value and the Y-coordinate minimum value; and obtaining a Z coordinate maximum value and a Z coordinate minimum value of the object plane, and calculating the Z direction length of the object plane according to the Z coordinate maximum value and the Z coordinate minimum value.
Further, the second step specifically includes: calculating and obtaining an object plane YZ ratio eta YZ according to the Y-direction length and the Z-direction length of the object plane, exchanging the coordinates of the object plane YZ when the object plane YZ ratio eta YZ is more than or equal to 1, and repeating the first step and the second step; when the object plane YZ ratio eta YZ is smaller than 1, the object plane YZ coordinates are kept unchanged.
Further, the third step specifically includes: dividing any object plane into n sections along the Y positive direction and the Z positive direction by taking (Y min,Zmin) as an origin, wherein each section has unit length of d=Z L/n to construct n multiplied by n grid blocks, Y min is a minimum value of Y coordinates, Z min is a minimum value of Z coordinates, and Z L is the length of the Z direction.
Further, in step six, the object plane slenderness ratio coefficient η dL may be based onAnd obtaining, wherein Y L is the length in the Y direction, and d m is the maximum value of the distances from all the nodes on the object plane to the fitting straight line.
Further, calculating and obtaining the object plane variance coefficient of any object plane according to the distance variance coefficient of each object plane specifically includes: obtaining a distance variance coefficient d v1,dv2,…,dvr of each object plane respectively; calculating a variance maximum d v_max＝max(dv1,dv2,…,dvr of the object planes according to the distance variance coefficient d v1,dv2,…,dvr of each object plane; and calculating and obtaining the object plane variance coefficient of any object plane according to the distance variance coefficient and the variance maximum value of any object plane.
Further, the object plane variance coefficient η dVi of any object plane can be obtained by calculating according to η dVi＝dvi/dv_max, i=1, 2, …, r, where d vi is the distance variance coefficient of the i object plane.
Further, the step eight specifically includes: comparing the object plane variance coefficient of any object plane with a set object plane variance coefficient threshold value, and comparing the object plane slenderness ratio coefficient of any object plane with a set object plane slenderness ratio coefficient threshold value, wherein when the object plane variance coefficient of any object plane is smaller than the set object plane variance coefficient threshold value and the object plane slenderness ratio coefficient of any object plane is smaller than the set object plane slenderness ratio coefficient threshold value, any object plane belongs to the wing object plane; otherwise, any object plane belongs to the wing object plane.
Further, the object plane variance coefficient threshold was set to 0.03, and the object plane slenderness ratio coefficient threshold was set to 0.06.
Further, the Y-direction length Y L may be obtained by calculation according to Y L＝Ymax-Ymin, and the Z-direction length Z L may be obtained by calculation according to Z L＝Zmax-Zmin, where Y max is a Y-coordinate maximum, Y min is a Y-coordinate minimum, Z max is a Z-coordinate maximum, and Z min is a Z-coordinate minimum.
By applying the technical scheme of the invention, the object plane type identification method based on the two-dimensional point set is provided, the method aims at the characteristics of small slenderness ratio and uniform occupation distribution of the object plane, all nodes of the object plane are mapped into each grid partition by dividing grids of the object plane, the grids with the object plane nodes are marked with center points, the center point median in a Z-direction unit length center point number array is calculated and obtained, and the center point coordinates in all Z-direction sections meeting the requirements of |s j-m|＜szm, j=1, 2 are fitted according to the center point median to obtain a fitting straight line, so that noise occupation can be removed, and the accuracy of subsequent data processing is improved; after the fitting straight line is obtained, calculating and obtaining a distance variance coefficient and a distance maximum value according to the distances from all the nodes on any object plane to the fitting straight line, and calculating and obtaining an object plane slenderness ratio coefficient according to the distance variance and the distance maximum value; calculating and obtaining object plane variance coefficients of all object planes according to the distance variance coefficients of all object planes aiming at the plurality of object planes; finally, the object plane variance coefficient of any object plane is compared with the set object plane variance coefficient threshold value, and the slenderness ratio coefficient of any object plane is compared with the set object plane slenderness ratio coefficient threshold value to judge whether any object plane belongs to the wing object plane or the body object plane. In addition, in the invention, after the Y-direction length and the Z-direction length of the object plane are obtained, the object plane YZ ratio is calculated and obtained according to the Y-direction length and the Z-direction length of the object plane, and whether the object plane YZ coordinate interchange is carried out or not is judged according to the object plane YZ ratio.
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The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. It is evident that the drawings in the following description are only some embodiments of the present invention and that other drawings may be obtained from these drawings without inventive effort for a person of ordinary skill in the art.
Fig. 1 shows an object plane projection effect diagram provided according to a specific embodiment of the present invention.
Detailed Description
It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. The following description of at least one exemplary embodiment is merely exemplary in nature and is in no way intended to limit the application, its application, or uses. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present application. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.
The relative arrangement of the components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless it is specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective parts shown in the drawings are not drawn in actual scale for convenience of description. Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but should be considered part of the specification where appropriate. In all examples shown and discussed herein, any specific values should be construed as merely illustrative, and not a limitation. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further discussion thereof is necessary in subsequent figures.
As shown in fig. 1, according to a specific embodiment of the present invention, there is provided a two-dimensional point set-based object plane type identification method, including: step one, obtaining two-dimensional coordinate points of all nodes on any object plane, and calculating the Y-direction length and the Z-direction length of the obtained object plane; calculating and obtaining an object plane YZ ratio according to the Y-direction length and the Z-direction length of the object plane, and judging whether to exchange the coordinates of the object plane YZ according to the object plane YZ ratio; step three, any object plane is subjected to grid division to construct n multiplied by n grid blocks; mapping all nodes of any object plane into each grid partition, marking the center point of the grid with the object plane nodes, and calculating to obtain a Z-direction unit length center point number array S 1,S2,…,Sn; step five, calculating and obtaining a central point median S ZM in a central point number array S 1,S2,…,Sn of a Z-direction unit length, judging whether the number of central points in each section of the Z-direction unit length meets |s j-m|＜szm, j=1, 2, n, extracting central point coordinates in all Z-direction sections meeting the requirements of |s j-m|＜szm, j=1, 2, n, and fitting to obtain a fitting straight line according to the central point coordinates in all Z-direction sections meeting the requirements of |s j-m|＜szm, j=1, 2, m=1-3; step six, calculating and obtaining a distance variance coefficient and a distance maximum value according to the distances from all the nodes on any object plane to the fitting straight line, and calculating and obtaining an object plane slenderness ratio coefficient according to the distance variance and the distance maximum value; step seven, repeating the step one to the step six for a plurality of object planes, calculating and obtaining the distance variance coefficient and the object plane slenderness ratio coefficient of each object plane, and calculating and obtaining the object plane variance coefficient of each object plane according to the distance variance coefficient of each object plane; and step eight, comparing the object plane variance coefficient of any object plane with a set object plane variance coefficient threshold value, and comparing the slenderness ratio coefficient of any object plane with a set object plane slenderness ratio coefficient threshold value to judge that any object plane belongs to the wing object plane or the body object plane.
By using the configuration mode, the object plane type identification method based on the two-dimensional point set is provided, the method aims at the characteristics of small slenderness and uniform occupation distribution of the wing object plane, all nodes of the object plane are mapped into each grid partition by dividing grids of the object plane, the grids with the object plane nodes are marked with center points, the center point median in the Z-direction unit length center point number array is calculated and obtained, and the center point coordinates in all Z-direction segments meeting the requirements of |s j-m|＜szm, j=1, 2 are fitted according to the center point median to obtain a fitting straight line, so that noise occupation can be removed, and the accuracy of subsequent data processing is improved; after the fitting straight line is obtained, calculating and obtaining a distance variance coefficient and a distance maximum value according to the distances from all the nodes on any object plane to the fitting straight line, and calculating and obtaining an object plane slenderness ratio coefficient according to the distance variance and the distance maximum value; calculating and obtaining object plane variance coefficients of all object planes according to the distance variance coefficients of all object planes aiming at the plurality of object planes; finally, the object plane variance coefficient of any object plane is compared with the set object plane variance coefficient threshold value, and the slenderness ratio coefficient of any object plane is compared with the set object plane slenderness ratio coefficient threshold value to judge whether any object plane belongs to the wing object plane or the body object plane. In addition, in the invention, after the Y-direction length and the Z-direction length of the object plane are obtained, the object plane YZ ratio is calculated and obtained according to the Y-direction length and the Z-direction length of the object plane, and whether the object plane YZ coordinate interchange is carried out or not is judged according to the object plane YZ ratio.
Specifically, in the invention, in order to identify the type of the object plane, two-dimensional coordinate points of all nodes on any object plane are firstly required to be acquired, and the Y-direction length and the Z-direction length of the acquired object plane are calculated. In the invention, the first step specifically comprises the following steps: acquiring two-dimensional coordinate points of all nodes on any object plane, acquiring a Y-coordinate maximum value and a Y-coordinate minimum value of the object plane, and calculating the Y-direction length of the object plane according to the Y-coordinate maximum value and the Y-coordinate minimum value; and obtaining a Z coordinate maximum value and a Z coordinate minimum value of the object plane, and calculating the Z direction length of the object plane according to the Z coordinate maximum value and the Z coordinate minimum value.
As a specific embodiment of the invention, YZ two-dimensional coordinate points of all nodes on any object plane are output, and the number of the nodes is recorded as k as shown as a node A in fig. 1. Obtaining an object plane Y coordinate maximum value Y max and a Y coordinate minimum value Y max, a Z coordinate maximum value Z max and a Z coordinate minimum value Z min, and solving a Y direction length and a Z direction length, wherein the Y direction length Y L can be obtained according to Y L＝Ymax-Ymin calculation, and the Z direction length Z L can be obtained according to Z L＝Zmax-Zmin calculation. In the invention, the Y direction refers to the direction of the symmetrical surface of the aircraft, the X direction refers to the direction of the aircraft nose towards the aircraft tail, and the Z direction is determined according to the right hand rule.
Further, after the length in the Y direction and the length in the Z direction are obtained, the object plane YZ ratio can be calculated and obtained according to the length in the Y direction and the length in the Z direction of the object plane, and whether the coordinate interchange of the object plane YZ is performed is judged according to the object plane YZ ratio. In the invention, the second step specifically comprises: calculating and obtaining an object plane YZ ratio eta YZ according to the Y-direction length and the Z-direction length of the object plane, exchanging the coordinates of the object plane YZ when the object plane YZ ratio eta YZ is more than or equal to 1, and repeating the first step and the second step; when the object plane YZ ratio eta YZ is smaller than 1, the object plane YZ coordinates are kept unchanged. Under the configuration mode, through calculating the object plane YZ ratio eta YZ, when the object plane YZ ratio eta YZ is larger than or equal to 1, the coordinates of the object plane YZ are interchanged, and the mode can convert the vertical airfoil surfaces into the horizontal plane airfoil surfaces, thereby being convenient for subsequent resolving and preventing the condition of no resolving in the resolving process.
As a specific embodiment of the invention, defining the object plane YZ ratio eta YZ＝YL/ZL, if eta YZ is more than or equal to 1, exchanging the coordinates of the object plane YZ, and carrying out the operation of the step I and the step II again; if 0 < eta YZ < 1, the next step is continued.
Further, in the present invention, after the object plane YZ ratio is determined, any object plane may be subjected to meshing to construct n×n mesh blocks. In the invention, the third step specifically comprises: dividing any object plane into n sections along the Y positive direction and the Z positive direction by taking (Y min,Zmin) as an origin, wherein each section has unit length of d=Z L/n to construct n multiplied by n grid blocks, Y min is a minimum value of Y coordinates, Z min is a minimum value of Z coordinates, and Z L is the length of the Z direction.
As a specific embodiment of the present invention, any object plane is divided into n segments in the Y positive direction and the Z positive direction with (Y min,Zmin) as an origin, and each segment has a unit length of d=z L/n, and n×n grid blocks are constructed, where n=80 to 120, as shown in B in fig. 1.
Further, after the object plane grid division is completed, all nodes of any object plane can be mapped into each grid partition, the grids with the object plane nodes are marked with center points, and the number array S 1,S2,…,Sn of the center points in the unit length of the Z direction is calculated and obtained.
As a specific embodiment of the present invention, all two-dimensional nodes of the object plane are mapped to each grid block in the third step, and the center points of the grid blocks with the object plane nodes are marked (if there is an object plane node in a certain grid block, the center points of the grid blocks are marked), so as to obtain a set of all the center points, and as shown in fig. 1C, obtain a number array S 1,S2,…,Sn of center points in each unit length in the Z direction.
Further, after the number array S 1,S2,…,Sn of the center points in the unit length in the Z direction is obtained, the median S ZM of the center points in the number array S 1,S2,…,Sn of the center points in the unit length in the Z direction can be calculated, and whether the number of the center points in each section in the Z direction satisfies |s j-m|＜szm, j=1, 2,..n and the labeling is performed, the center point coordinates in all the Z-direction sections satisfying |s j-m|＜szm, j=1, 2,..n are extracted, and a fitting straight line L (y, Z) is obtained by fitting the center point coordinates in all the Z-direction sections satisfying |s j-m|＜szm, j=1, 2., n, as shown in D in fig. 1, wherein m=1 to 3.
Under the configuration mode, the object plane is assumed to be an airfoil, some noise points such as the points on an engine are arranged on the object plane node, and if the difference is too large, the noise points are considered by judging the difference between the points and the median of all the points; if the difference is in the set threshold range, the noise point is considered to be not the noise point, so that the noise can be removed efficiently, and the judgment accuracy is improved.
Further, after the fitting curve is obtained, a distance variance coefficient and a distance maximum value can be obtained through calculation according to the distances from all the nodes on any object plane to the fitting straight line, and an object plane slenderness ratio coefficient can be obtained through calculation according to the distance variance and the distance maximum value. In the sixth step, the object plane slenderness ratio coefficient eta dL can be determined according toAnd obtaining, wherein Y L is the length in the Y direction, and d m is the maximum value of the distances from all the nodes on the object plane to the fitting straight line.
As a specific embodiment of the invention, solving the distances d 1,d2,…,dk from the k object plane nodes to the fitting straight line L (y, z), solving the distance variance d v and the distance maximum value d m of d 1,d2,…,dk, and defining the object plane slenderness ratio coefficient eta dL as
Further, after the object plane slenderness ratio coefficient is obtained, the steps one to six can be repeated for a plurality of object planes, the distance variance coefficient and the object plane slenderness ratio coefficient of each object plane are calculated and obtained, and the object plane variance coefficient of each object plane is calculated and obtained according to the distance variance coefficient of each object plane. In the invention, calculating and obtaining the object plane variance coefficient of any object plane according to the distance variance coefficient of each object plane specifically comprises the following steps: obtaining a distance variance coefficient d v1,dv2,…,dvr of each object plane respectively; calculating a variance maximum d v_max＝max(dv1,dv2,…,dvr of the object planes according to the distance variance coefficient d v1,dv2,…,dvr of each object plane; and calculating and obtaining the object plane variance coefficient of any object plane according to the distance variance coefficient and the variance maximum value of any object plane. The object plane variance coefficient η dVi of any object plane can be calculated and obtained according to η dVi＝dvi/dv_max, i=1, 2, …, r.
As a specific embodiment of the present invention, assuming that there are r object planes, repeating the steps one to six to obtain a distance variance coefficient d v1,dv2,…,dvr and an object plane slenderness ratio coefficient η dL1,ηdL2,…,ηdLr under each object plane. Solving for the maximum variance d v_max＝max(dv1,dv2,…,dvr for all object planes). The object plane variance coefficient η dVi＝dvi/dv_max, i=1, 2, …, r is defined.
Further, after the object plane variance coefficient and the object plane slenderness ratio coefficient of each object plane are obtained, the object plane variance coefficient of any object plane can be compared with a set object plane variance coefficient threshold value, and the slenderness ratio coefficient of any object plane can be compared with a set object plane slenderness ratio coefficient threshold value to judge that any object plane belongs to the wing object plane or the body object plane. In the invention, the characteristics of small slenderness ratio and uniform space occupation distribution of wing object surfaces are considered, the object surface variance coefficient of any object surface is compared with the set object surface variance coefficient threshold value, and the slenderness ratio coefficient of any object surface is compared with the set object surface slenderness ratio coefficient threshold value, when the object surface variance coefficient of any object surface is smaller than the set object surface variance coefficient threshold value and the slenderness ratio coefficient of any object surface is smaller than the set object surface slenderness ratio coefficient threshold value, any object surface belongs to the wing object surface; otherwise, any object plane belongs to the wing object plane.
As a specific embodiment of the present invention, the object plane variance coefficient threshold is set to be 0.03, the object plane slenderness ratio coefficient threshold is set to be 0.06, when the object plane variance coefficient η dVi of any object plane is smaller than 0.03, the slenderness ratio coefficient η dLi of any object plane is smaller than 0.06, i=1, 2, …, r, any object plane i is marked as a wing object plane, and other object planes are marked as body object planes.
For further understanding of the present invention, the following describes in detail the object plane type identification method based on the two-dimensional point set provided by the present invention with reference to fig. 1.
Outputting YZ two-dimensional coordinate points of all nodes on any object plane, and recording the number of the nodes as k as shown by a node A in fig. 1. Obtaining an object plane Y coordinate maximum value Y max and a Y coordinate minimum value Y max, a Z coordinate maximum value Z max and a Z coordinate minimum value Z min, and solving a Y direction length and a Z direction length, wherein the Y direction length Y L can be obtained according to Y L＝Ymax-Ymin calculation, and the Z direction length Z L can be obtained according to Z L＝Zmax-Zmin calculation. In the invention, the Y direction refers to the direction of the symmetrical surface of the aircraft, the X direction refers to the direction of the aircraft nose towards the aircraft tail, and the Z direction is determined according to the right hand rule.
Step two, defining an object plane YZ ratio eta YZ＝YL/ZL, and if eta YZ is more than or equal to 1, exchanging the coordinates of the object plane YZ, and carrying out the operation of the step one and the step two again; if 0 < eta YZ < 1, the next step is continued.
And thirdly, dividing any object plane into n sections along the Y positive direction and the Z positive direction by taking (Y min,Zmin) as an origin, wherein each section has the unit length of d=Z L/n, constructing n multiplied by n grid blocks, and n=80-120, as shown in B in fig. 1.
And step four, mapping all two-dimensional nodes of the object plane to each grid block in the step three, marking the grid block center points with the object plane nodes (marking the center points of the grid blocks if the object plane nodes exist in a certain grid block), obtaining a set of all the center points, and obtaining a center point number array S 1,S2,…,Sn in each unit length in the Z direction as shown in C in fig. 1.
And fifthly, calculating and obtaining a central point median S ZM in the central point number array S 1,S2,…,Sn of the unit length of the Z direction, judging whether the central point number in the unit length of each section of the Z direction meets |s j-m|＜szm, j=1, 2, and performing marking, extracting central point coordinates in all Z-direction sections meeting the conditions |s j-m|＜szm, j=1, 2, and n, and fitting the central point coordinates in all Z-direction sections meeting the conditions |s j-m|＜szm, j=1, 2, and obtaining a fitting straight line L (y, Z) according to the central point coordinates in all Z-direction sections meeting the conditions |s j-m|＜szm, j=1, 2, and performing fitting as shown in D in fig. 1, wherein m=1-3.
Step six, solving the distances d 1,d2,…,dk from the k object plane nodes to the fitting straight line L (y, z), solving the distance variance coefficient d v and the distance maximum value d m of d 1,d2,…,dk, and defining the object plane slenderness ratio coefficient eta dL as
Step seven, supposing r object planes, repeating the steps one to six to obtain a distance variance coefficient d v1,dv2,…,dvr and an object plane slenderness ratio coefficient eta dL1,ηdL2,…,ηdLr under each object plane. Solving for the maximum variance d v_max＝max(dv1,dv2,…,dvr for all object planes). Object plane variance coefficients η dVi＝dvi/dv_max, i=1, 2, …, r are defined, where d vi is the distance variance coefficient of the i-th object plane.
Step eight, setting the object plane variance coefficient threshold value to be 0.03, setting the object plane slenderness ratio coefficient threshold value to be 0.06, and for any object plane, when the object plane variance coefficient eta dVi of any object plane is smaller than 0.03, the slenderness ratio coefficient eta dLi of any object plane is smaller than 0.06, i=1, 2, … and r, marking any object plane i as a wing object plane, and marking other object planes as a body object plane.
In summary, the invention provides an object plane type identification method based on a two-dimensional point set, which establishes identification criteria of wing object planes and body object planes, is convenient for high-efficiency unified comparison analysis, can obviously improve the accuracy and efficiency of load analysis, and is convenient for engineering application. The method can be suitable for automatic identification of object plane loads of various types of aircrafts, and can be effectively suitable for load design of aircrafts, in particular for load design with complex appearance, more object planes and large number of manual identification.
Spatially relative terms, such as "above … …," "above … …," "upper surface on … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial location relative to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "above" or "over" other devices or structures would then be oriented "below" or "beneath" the other devices or structures. Thus, the exemplary term "above … …" may include both orientations "above … …" and "below … …". The device may also be positioned in other different ways (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
In addition, the terms "first", "second", etc. are used to define the components, and are only for convenience of distinguishing the corresponding components, and the terms have no special meaning unless otherwise stated, and therefore should not be construed as limiting the scope of the present invention.
The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. The object plane type identification method based on the two-dimensional point set is characterized by comprising the following steps of:
step one, obtaining two-dimensional coordinate points of all nodes on any object plane, and calculating and obtaining Y-direction length and Z-direction length of the object plane;
Calculating and obtaining an object plane YZ ratio according to the Y-direction length and the Z-direction length of the object plane, and judging whether to exchange the coordinates of the object plane YZ according to the object plane YZ ratio;
step three, any object plane is subjected to grid division to construct n multiplied by n grid blocks;
Mapping all nodes of any object plane into each grid partition, marking the center point of the grid with the object plane node, and calculating to obtain a Z-direction unit length center point number array S 1,S2,…,Sn;
Step five, calculating and obtaining a central point median S ZM in the central point number array S 1,S2,…,Sn of the unit length of the Z direction, judging whether the number of central points in the unit length of each section of the Z direction meets |s j-m|＜szm, j=1, 2, & gt, n, extracting central point coordinates in all Z-direction sections meeting the requirements of |s j-m|＜szm, j=1, 2, & gt, n, and fitting to obtain a fitting straight line according to the central point coordinates in all Z-direction sections meeting the requirements of |s j-m|＜szm, j=1, 2, & gt, n, wherein m=1-3;
step six, calculating and obtaining a distance variance coefficient and a distance maximum value according to the distances from all the nodes on any object plane to the fitting straight line, and calculating and obtaining an object plane slenderness ratio coefficient according to the distance variance and the distance maximum value;
Step seven, repeating the step one to the step six for a plurality of object planes, calculating and obtaining the distance variance coefficient and the object plane slenderness ratio coefficient of each object plane, and calculating and obtaining the object plane variance coefficient of each object plane according to the distance variance coefficient of each object plane;
and step eight, comparing the object plane variance coefficient of any object plane with a set object plane variance coefficient threshold value, and comparing the object plane slenderness ratio coefficient of any object plane with a set object plane slenderness ratio coefficient threshold value to judge that any object plane belongs to the wing object plane or the body object plane.
2. The object plane type identification method based on the two-dimensional point set according to claim 1, wherein the first step specifically comprises: acquiring two-dimensional coordinate points of all nodes on any object plane, acquiring a Y-coordinate maximum value and a Y-coordinate minimum value of the object plane, and calculating and acquiring the Y-direction length of the object plane according to the Y-coordinate maximum value and the Y-coordinate minimum value; and obtaining a Z coordinate maximum value and a Z coordinate minimum value of the object plane, and calculating and obtaining the Z direction length of the object plane according to the Z coordinate maximum value and the Z coordinate minimum value.
3. The object plane type identification method based on the two-dimensional point set according to claim 2, wherein the step two specifically comprises: calculating and obtaining an object plane YZ ratio eta YZ according to the Y-direction length and the Z-direction length of the object plane, and exchanging the coordinates of the object plane YZ when the object plane YZ ratio eta YZ is larger than or equal to 1, and repeating the first step and the second step; when the object plane YZ ratio eta YZ is smaller than 1, the object plane YZ coordinates are kept unchanged.
4. The object plane type identification method based on the two-dimensional point set according to claim 3, wherein the step three specifically comprises: dividing any object plane into n sections along the Y positive direction and the Z positive direction by taking (Y min,Zmin) as an origin, wherein each section has the unit length of d=Z L/n to construct n multiplied by n grid blocks, Y min is a minimum value of Y coordinates, Z min is a minimum value of Z coordinates, and Z L is the length of the Z direction.
5. The method according to claim 4, wherein in the sixth step, the object plane slenderness ratio coefficient η dL is determined according toAnd obtaining, wherein Y L is the length in the Y direction, and d m is the maximum distance from all nodes on the object plane to the fitting straight line.
6. The method for identifying object plane types based on two-dimensional point sets according to claim 5, wherein calculating and obtaining object plane variance coefficients of any object plane according to distance variance coefficients of the object planes specifically comprises: obtaining a distance variance coefficient d v1,dv2,…,dvr of each object plane respectively; calculating a variance maximum d v_max＝max(dv1,dv2,…,dvr of a plurality of object planes according to a distance variance coefficient d v1,dv2,…,dvr of each object plane; and calculating and obtaining the object plane variance coefficient of any object plane according to the distance variance coefficient of any object plane and the variance maximum value.
7. The two-dimensional point set-based object plane type identification method according to claim 6, wherein the object plane variance coefficient η dVi of any object plane is calculated and obtained according to η dVi＝dvi/dv_max, i=1, 2, …, r, wherein d vi is the distance variance coefficient of the i-th object plane.
8. The object plane type identification method based on the two-dimensional point set according to claim 7, wherein the step eight specifically comprises: comparing the object plane variance coefficient of any object plane with a set object plane variance coefficient threshold value, and comparing the object plane slenderness ratio coefficient of any object plane with a set object plane slenderness ratio coefficient threshold value, wherein when the object plane variance coefficient of any object plane is smaller than the set object plane variance coefficient threshold value and the object plane slenderness ratio coefficient of any object plane is smaller than the set object plane slenderness ratio coefficient threshold value, any object plane belongs to the wing object plane; otherwise, any object plane belongs to the wing object plane.
9. The two-dimensional point set-based object plane type identification method according to claim 8, wherein the set object plane variance coefficient threshold is 0.03, and the set object plane slenderness ratio coefficient threshold is 0.06.
10. The two-dimensional point set-based object plane type recognition method according to claim 9, wherein the Y-direction length Y L is calculated and obtained according to Y L＝Ymax-Ymin, and the Z-direction length Z L is calculated and obtained according to Z L＝Zmax-Zmin, wherein Y max is a Y-coordinate maximum value, Y min is a Y-coordinate minimum value, Z max is a Z-coordinate maximum value, and Z min is a Z-coordinate minimum value.
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