Rapid registration method and registration positioning device for aircraft assembly

Abstract

The invention discloses a rapid registration method and a registration positioning device for aircraft assembly, and the method comprises the steps: building a three-dimensional stl model of an aircraft part, and taking a crossed rib on a frame beam of the aircraft part as a virtual-real matching feature point; a plane equation R11 and a plane equation RR2 of the two ribs are obtained respectively, and then a middle plane equation RMid1 and a middle plane equation RMid2 of the two ribs are obtained; and combining the plane equations RMid1 and RMid2 with the top plane equation RTop, and calculating to obtain a plane intersection point as a theoretical registration coordinate point F (x, y, z). And finally, according to the thickness of the real object registration point device, adjusting the offset to obtain an aircraft assembly registration point Final (x + s * a, y + s * b and z + s * c) so as to carry out registration assembly. The method solves the problems that in the prior art, the theoretical coordinates of the registration points cannot be rapidly obtained, the real object registration points are not accurate enough to place, and the adaptability is not high, and has good practicability.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of aircraft assembly, and particularly relates to a rapid registration method and a registration positioning device for aircraft assembly. BACKGROUND

[0002] With the development of modern aircraft component assembly technology, augmented reality technology is gradually applied to various assembly processes and can be used to assist operators in assembling complex components, such as three-dimensional projection, which can project the shape of the parts to be assembled and assembly information to the assembly position. However, due to the complexity of the assembly environment, accurate and rapid virtual-real matching between virtual model information and the real object is required, and the conversion matrix of the theoretical three-dimensional coordinates and the image two-dimensional coordinates needs to be established to complete the overall conversion of the model. This process requires placing a real registration point for positioning the uv coordinates of the image, and the three-dimensional theoretical registration coordinates of the model corresponding to the uv coordinates of the real object. In this process, the accurate placement of the real registration point and the rapid selection of the theoretical registration coordinates are the prerequisites for ensuring the accuracy and convenience of augmented reality technology. However, the placement position of the registration point is often limited by the environment, such as obstruction, size mismatch, etc. Therefore, the registration point position needs to be selected temporarily on site. However, the size of the registration point may not be suitable for placement, and the theoretical registration coordinates also need to be reacquired.

[0003] For example, the existing Chinese patent CN112613123A discloses an aircraft pipeline AR three-dimensional registration method based on deep learning and image processing, which includes: collecting multi-view images of a 3D model of an aircraft pipeline part; preprocessing the collected multi-view images to form a contour image dataset under multi-view; training the contour image dataset through a deep learning network; preprocessing the real scene image of the aircraft pipeline part; and inputting the preprocessed real scene image into the trained deep learning network to detect the object and its bounding box in the real scene image; determining whether there is a registration object in the real scene image; when there is a registration object in the real scene image, determining the six-degree-of-freedom pose of the registration object in the camera coordinate system to complete the registration; otherwise, outputting no registration object information in the real scene image. SUMMARY

[0004] The present application aims to provide a rapid registration method and a registration positioning device for aircraft assembly, which solves the above problems.

[0005] The present application mainly realizes the following technical solutions:

[0006] A rapid registration method for aircraft assembly, a three-dimensional stl model of an aircraft component is established, and the intersecting ribs on the frame beam of the aircraft component are used as virtual-real matching feature points; the method includes the following steps:

[0007] Step S1: obtaining a plane equation and a point coordinate on the plane; based on any one rib side plane of the intersecting rib, obtaining the plane equation R1 of the rib side plane; then, obtaining the coordinate (x1, y1, z1) of any point P1 on the plane, and a straight line L1 passing through the point P1 and having the same normal direction as R1;

[0008] Step S2: finding the opposite plane of the rib in step S1; traversing all triangular planes of the three-dimensional stl model to obtain the plane equation R1_1 of the other plane of the rib in step S1 and the intersection point coordinate P1_1;

[0009] Step S3: calculating the middle plane equation of the rib in step S1; translating the plane equation R1_1 by a distance d=(d1 / 2) along the normal direction to obtain the middle plane equation R_Mid1; wherein d1 is the projection distance of the intersection point coordinate of the straight line L1 and the triangular plane in step S2 from the plane equation R1;

[0010] Step S4: similarly, repeating steps S1-S3 to obtain the middle plane equation R_Mid2 of the other rib;

[0011] Step S5: obtaining the top plane equation R_Top of the intersecting rib, and the normal vector thereof is M(a, b, c);

[0012] Step S6: calculating the theoretical intersection point; simultaneously solving the plane equations R_Mid1, R_Mid2 and the top plane equation R_Top to obtain the plane intersection point as the theoretical registration coordinate point F(x, y, z);

[0013] Step S7: adjusting the offset according to the thickness of the real registration point device; offsetting the theoretical registration coordinate point F(x, y, z) by a thickness s from the normal M(a, b, c) of the top plane R_Top to obtain the final aircraft assembly registration point Final(x+s*a, y+s*b, z+s*c) for registration assembly.

[0014] In order to better realize the present application, further, in step S2, the triangular plane found satisfies:

[0015] a) the normal direction is parallel to the plane equation R1;

[0016] b) the intersection point of the straight line L1 and the triangular plane is in the triangular plane;

[0017] c) the projection distance d1 of the intersection point coordinate of the straight line L1 and the triangular plane from the plane equation R1 is the smallest, but should not be less than 1.

[0018] The application discloses a quick registration positioning device for aircraft assembly, which is based on the quick registration method for aircraft assembly and comprises a first registration part and a second registration part arranged corresponding to intersecting ribs on a frame beam, wherein the first registration part and the second registration part respectively comprise an adaptive fixer and a pin ring, one end of the adaptive fixer is provided with the pin ring, the bottom of the adaptive fixer is provided with a plug-in groove corresponding to the ribs, and the middle part of the pin ring is provided with a concentric circular groove corresponding to an aircraft assembly registration point.

[0019] In order to better realize the application, further, the plug-in groove is provided with a plurality of stepped groove corresponding to the ribs.

[0020] In order to better realize the application, further, one side of the pin ring is provided with a U-shaped frame, and the U-shaped frame is slidably plugged with the adaptive fixer.

[0021] In order to better realize the application, further, the two sides of the adaptive fixer are respectively provided with a plurality of installation sliding grooves from top to bottom.

[0022] The application has the following beneficial effects:

[0023] The application can quickly select a registration point and realize quick assembly through the quick registration positioning device, solves the problems that the theoretical coordinates of the registration point cannot be quickly obtained and the physical registration point is not accurately placed and has low adaptability in the prior art. Specifically, the adaptive fixer is placed on the rib to fix the middle surface position of the rib. One side of the pin ring is plugged on the adaptive fixer to extend the middle surface position, the aircraft assembly registration point is accurately positioned through riveting arrangement between the concentric circular grooves of the two pin rings, quick positioning assembly can be realized, and the application has good practicability. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a structural schematic view of the rib on the frame beam of the aircraft;

[0025] Figure 2 It is a schematic view of the aircraft assembly registration point of the intersecting ribs in vertical distribution;

[0026] Figure 3 It is a schematic view of the aircraft assembly registration point of the intersecting ribs in non-vertical distribution;

[0027] Figure 4 It is an exploded structural schematic view of the quick registration positioning device for aircraft assembly of the application;

[0028] Figure 5 It is a schematic view of the cooperation state of the first registration part and the second registration part;

[0029] Figure 6A schematic diagram showing the usage status of a rapid registration and positioning device for aircraft assembly based on aircraft assembly registration points;

[0030] Figure 7 A schematic diagram showing the usage status of a rapid registration and positioning device for aircraft assembly based on aircraft assembly registration points;

[0031] Figure 8 This is a schematic diagram of the plug slot structure. Detailed Implementation

[0032] Example 1:

[0033] A rapid registration method for aircraft assembly, such as Figure 1 As shown, during aircraft assembly, the stiffeners on the frame beam typically intersect in a cross shape. Their intersections are distinctive, structurally stable, and can be used as feature points (registration points) for virtual-real matching. This invention uses this feature to obtain the theoretical registration coordinates of the registration points, as shown below. Figure 2 and Figure 3 As shown, the specific steps are as follows:

[0034] Step S1: Obtain the plane equation and the coordinates of a point on the plane. Click on the side plane of one of the two intersecting ribs to obtain the plane equation R1 of that side: A1×x+B1×y+C1×z+D1=0. Click to obtain the coordinate point P1(x1, y1, z1) and the straight line L1 that passes through point P1 and has the same direction as the normal to R1.

[0035] Step S2: Find the opposite face of the rib. Traverse all triangular faces of the 3D STL model to obtain the plane equation and intersection coordinates of the opposite face of the corresponding rib. Based on the characteristics of the rib, the requirements for the triangular face to be found are as follows:

[0036] a) The normal direction is parallel to the plane equation R1.

[0037] b) The intersection of line L1 and the triangular plane lies within the triangular plane.

[0038] c) The projection distance d1 from the intersection point of line L1 and the triangular face to the plane equation R1 should be minimized, but not less than 1. Record the found plane equation as R1_1 and the intersection point coordinates as P1_1.

[0039] Step S3: Calculate the equation of the intermediate surface. Translate the plane equation R1_1 along the normal direction by a distance d = (d1 / 2) to obtain the equation of the intermediate surface R_Mid1.

[0040] Step S4: Calculate the equation of the middle surface of the other rib. For the other intersecting rib, repeat steps S1 to S3 to obtain the second middle surface R_Mid2.

[0041] Step S5: Obtain the top plane equation. Using the way of clicking in step S1, obtain the third plane equation R_Top, whose normal vector is M(a, b, c).

[0042] Step S6: Calculate the theoretical intersection point. Solve the equation set of the three planes R_Mid1, R_Mid2, R_Top, calculate the result, call the mathematical library function to calculate the equation, and obtain the theoretical registration coordinate point F(x, y, z).

[0043] Step S7: Adjust the offset according to the thickness of the real registration point device. In actual use, the registration point has a certain thickness, and the theoretical registration coordinate F(x, y, z) should be offset by the thickness s to the normal M(a, b, c) of the plane R_Top. Obtain the final aircraft assembly registration point Final(x+s*a, y+s*b, z+s*c).

[0044] Example 2:

[0045] A quick registration positioning device for aircraft assembly is needed to capture the UV coordinates of the corresponding position of the real object in the camera after the theoretical registration coordinate point is obtained in the virtual-real feature point matching process. The accuracy of the coordinates greatly affects the matching accuracy. Therefore, the registration positioning device is designed.

[0046] As shown in Figures 4-7 , the registration positioning device mainly includes a first registration part and a second registration part, and the first registration part and the second registration part respectively include an adaptive fixer and a plug-in ring; one end of the adaptive fixer is provided with a plug-in ring, and the bottom of the adaptive fixer is provided with a plug-in slot corresponding to the length direction of the rib.

[0047] As shown in Figure 6 and Figure 7 , the adaptive fixer is placed on the rib to fix the middle surface position of the rib. The plug-in ring is inserted into the adaptive fixer to extend the middle surface position, and the cross surface coordinates are accurately positioned through the riveting setting between the concentric grooves of the two plug-in rings.

[0048] As shown in Figure 8 , the plug-in slot corresponding to the rib is provided with a plurality of stepped groove slots. The adaptive fixer is mainly used to position the middle surface of the rib, and a plurality of stepped thicknesses are designed according to the actual use environment to meet the use of different rib thicknesses. The slots on both sides are used to insert the two fixing feet extended by the plug-in ring.

[0049] The plug-in ring is provided with two concentric grooves of different sizes, as shown in Figure 5As shown, the concentric circular grooves can be nested together. The camera can obtain the circular pixel uv coordinates by identifying the center. In order to increase the device features for the camera to identify, the first registration part of the pin ring is printed white, and the second registration part of the pin ring is printed black, so that when the nesting is completed, the device appears as a black border white circle, which can greatly improve the success rate of camera identification.

[0050] But because the pin ring has a certain thickness, in actual use, a pin ring thickness should be added to the normal direction of the theoretical registration coordinates, and in the theoretical registration coordinate fast acquisition method of the patent, the surface normal can be obtained, and the theoretical registration coordinates after lifting can be automatically calculated according to the thickness preset in advance.

[0051] The above is only a preferred embodiment of the present application, and does not limit the present application in any form. Any simple modification or equivalent change of the above embodiment according to the technical essence of the present application falls within the protection scope of the present application.

Claims

1. A rapid registration method for aircraft assembly, characterized by, A three-dimensional stl model of an aircraft component is established, and a cross rib on a frame beam of the aircraft component is taken as a virtual-real matching feature point. The method comprises the following steps: Step S1: obtaining a plane equation and a coordinate of a point on the plane; obtaining a plane equation R1 of a side plane of any rib of the cross rib, and then obtaining a coordinate (x1, y1, z1) of a point P1 on the plane and a straight line L1 passing through the point P1 and having the same normal direction as the plane equation R1; Step S2: finding an opposite plane of the rib in step S1; traversing all triangular planes of the three-dimensional stl model to obtain a plane equation R1_1 of the other plane of the rib in step S1 and a coordinate P1_1 of the intersection point; Step S3: calculating a middle plane equation of the rib in step S1; translating the plane equation R1_1 along the normal direction by a distance d=(d1 / 2) to obtain a middle plane equation R_Mid1; wherein d1 is a projection distance of the coordinate of the intersection point of the straight line L1 and the triangular plane in step S2 from the plane equation R1; Step S4: repeating steps S1-S3 to obtain a middle plane equation R_Mid2 of the other rib; Step S5: obtaining a top plane equation R_Top of the cross rib, and a normal vector M(a, b, c) of the top plane equation R_Top; Step S6: calculating a theoretical intersection point; combining the plane equations R_Mid1, R_Mid2 and the top plane equation R_Top to obtain a plane intersection point as a theoretical registration coordinate point F(x, y, z); Step S7: adjusting an offset according to a thickness of a real registration point device; offsetting the theoretical registration coordinate point F(x, y, z) by a thickness s along the normal M(a, b, c) of the top plane R_Top to obtain a final aircraft assembly registration point Final(x+s*a, y+s*b, z+s*c) for registration assembly.

2. The rapid registration method for aircraft assembly of claim 1, wherein, In step S2, the triangular plane satisfies: a) the normal direction is parallel to the plane equation R1; b) the intersection point of the straight line L1 and the triangular plane is in the triangular plane; c) the projection distance d1 of the coordinate of the intersection point of the straight line L1 and the triangular plane from the plane equation R1 is the smallest, but should not be less than 1.

3. A rapid registration positioning device for aircraft assembly, based on the rapid registration method for aircraft assembly according to claim 1 or 2, characterized in that, The first registration part and the second registration part arranged on the cross rib on the frame beam, the first registration part and the second registration part respectively comprising an adaptive fixer and a plug ring, one end of the adaptive fixer being provided with the plug ring; the bottom of the adaptive fixer being provided with a plug-in slot corresponding to the rib, and the middle of the plug ring being provided with a concentric circular groove corresponding to the aircraft assembly registration point.

4. A rapid registration positioning device for aircraft assembly according to claim 3, wherein, The plug-in slot is provided with a plurality of stepped groove slots corresponding to the rib.

5. The rapid registration positioning device for aircraft assembly of claim 3, wherein, One side of the plug ring is provided with a U-shaped frame, and the U-shaped frame is slidably inserted into the adaptive fixer.

6. A rapid registration positioning device for aircraft assembly according to claim 5, wherein, The adaptive fixer is provided with a plurality of mounting sliding grooves from top to bottom on both sides.

Images