A rapid registration method and registration positioning device for aircraft assembly

Abstract

The application discloses a kind of quick registration method and registration positioning device for aircraft assembly, establishes the three-dimensional stl model of aircraft component, as virtual and real matching feature points with the cross rib on the frame beam of aircraft component. Plane equation R1_1 and plane equation R1_2 of two ribs are obtained respectively, and then the middle surface equation R_Mid1 and the middle surface equation R_Mid2 of two ribs are obtained. The surface intersection point is obtained by simultaneously solving plane equation R_Mid1, R_Mid2 and top plane equation R_Top, as the theoretical registration coordinate point F (x, y, z). Finally, according to the thickness of the real registration point device, the offset is adjusted, and the aircraft assembly registration point Final (x+s*a, y+s*b, z+s*c) is obtained to carry out registration assembly. The application solves the problem that the theoretical coordinate of the registration point cannot be quickly obtained in the prior art, and the real registration point is not placed accurately and has low adaptability, and has good practicability.

Description

Technical Field

[0001] This invention belongs to the technical field of aircraft assembly, specifically relating to a rapid registration method and registration positioning device for aircraft assembly. Background Technology

[0002] With the development of modern aircraft component assembly technology, augmented reality (AR) technology is gradually being applied to various assembly processes. It can assist operators in assembling complex components, such as 3D projection, which projects the shape and assembly information of the parts to be assembled onto the assembly position. However, due to the complexity of the assembly environment, accurate and rapid virtual-to-real matching is required between the virtual model information and the physical object. This necessitates establishing a transformation matrix between theoretical 3D coordinates and image 2D coordinates to complete the overall model transformation. This process requires placing physical registration points to locate the UV coordinates of the image, as well as the corresponding 3D theoretical registration coordinates of the model at those physical UV coordinates. Accurate placement of physical registration points and rapid selection of theoretical registration coordinates are prerequisites for ensuring the accuracy and convenience of AR technology. However, currently, the placement of registration points is often limited by environmental constraints, such as occlusion or size mismatch, usually requiring temporary selection of registration point locations on-site. However, these locations may have unsuitable registration point sizes, making placement impossible, or their theoretical registration coordinates may need to be re-acquired.

[0003] For example, existing Chinese patent CN112613123A discloses an AR 3D registration method for aircraft pipes based on deep learning and image processing, including: acquiring multi-view images of 3D models of aircraft pipe parts; preprocessing the acquired multi-view images to form a contour image dataset under multi-view conditions; training the contour image dataset through a deep learning network; preprocessing real-world scene images of aircraft pipe parts; and feeding the preprocessed real-world scene images into the trained deep learning network to detect objects and their bounding boxes in the real-world scene images; determining whether there are registered objects in the real-world scene images; when there are registered objects in the real-world scene images, determining the six-degree-of-freedom pose of the registered objects in the camera coordinate system to complete the registration; otherwise, outputting information that there are no registered objects in the real-world scene images. Summary of the Invention

[0004] The purpose of this invention is to provide a rapid registration method and registration positioning device for aircraft assembly, in order to solve the above-mentioned problems.

[0005] This invention is mainly achieved through the following technical solutions:

[0006] A rapid registration method for aircraft assembly establishes a 3D STL model of the aircraft component, using the intersecting ribs on the frame beam of the aircraft component as virtual-to-real matching feature points; including the following steps:

[0007] Step S1: Obtain the plane equation and the coordinates of a point on the plane; Based on any side plane of the intersecting stiffeners, obtain the plane equation R1 of the side plane of the stiffener: A1x+B1y+C1z+D1=0; Then, obtain the coordinates (x1, y1, z1) of any point P1 on the plane, and the straight line L1 that passes through point P1 and has the same direction as the normal to R1.

[0008] Step S2: Find the opposite face of the rib in step S1; traverse all the triangular faces of the 3D STL model to obtain the plane equation R1_1 of the other face of the rib in step S1 and the coordinates of the intersection point P1_1;

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

[0010] Step S4: Similarly, repeat steps S1 to S3 to obtain the equation R_Mid2 of the middle surface of the other rib.

[0011] Step S5: Obtain the equation R_Top of the top plane of the intersecting stiffeners, with its normal vector being M(a, b, c);

[0012] Step S6: Calculate the theoretical intersection point; combine the plane equations R_Mid1, R_Mid2 and the top plane equation R_Top to calculate the intersection point of the planes, which is used as the theoretical registration coordinate point F(x, y, z);

[0013] Step S7: Adjust the offset according to the thickness of the physical registration point device; offset the theoretical registration coordinate point F(x, y, z) by the thickness s to 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 and assembly.

[0014] To better realize the present invention, further, in step S2, the triangular face sought satisfies:

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

[0016] b) The intersection of line L1 and the triangular plane lies within the triangular plane;

[0017] c) The distance d1 from the coordinates of the intersection point of line L1 and the triangular face to the projection distance of the plane equation R1 should be minimized, but should not be less than 1.

[0018] A rapid registration and positioning device for aircraft assembly, based on the aforementioned rapid registration method for aircraft assembly, includes a first registration part and a second registration part arranged on the cross ribs corresponding to the frame beam. The first registration part and the second registration part respectively include an adaptive retainer and a pin ring. One end of the adaptive retainer is provided with a pin ring. The bottom of the adaptive retainer is provided with a insertion groove corresponding to the rib. The middle part of the pin ring is provided with a concentric circular groove corresponding to the aircraft assembly registration point.

[0019] To better realize the present invention, the insertion groove is further provided with a plurality of stepped grooves corresponding to the reinforcing bars.

[0020] To better realize the present invention, a U-shaped frame is further provided on one side of the pin ring, and the U-shaped frame is slidably inserted into the adaptive fixer.

[0021] To better realize the present invention, further, several mounting grooves are provided on both sides of the adaptive fixer from top to bottom.

[0022] The beneficial effects of this invention are as follows:

[0023] This invention enables rapid selection of registration points and rapid assembly via a rapid registration and positioning device, solving the problems of existing technologies that cannot quickly obtain the theoretical coordinates of registration points, and that the placement of physical registration points is not precise enough and has low adaptability. Specifically, an adaptive retainer is placed on a rib, fixing the middle surface of the rib. One side of a pin ring is inserted into the adaptive retainer to extend the middle surface position. Through the riveting setting between the concentric grooves of the two pin rings, the aircraft assembly registration points are precisely positioned, enabling rapid positioning and assembly, and demonstrating good practicality. Attached Figure Description

[0024] Figure 1 A structural schematic diagram of the stiffening strips on the aircraft frame beam;

[0025] Figure 2 A schematic diagram of the assembly registration points for aircraft with vertically distributed intersecting ribs;

[0026] Figure 3 A schematic diagram of the assembly registration points for aircraft with non-vertically distributed intersecting ribs;

[0027] Figure 4 This is an exploded structural diagram of the rapid registration and positioning device for aircraft assembly according to the present invention.

[0028] Figure 5 This is a schematic diagram showing the coordination state of the first and second registration units.

[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 equation of the top plane. Using the clicking method in step S1, obtain the equation of the third face R_Top, whose normal vector is M(a, b, c).

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

[0043] Step S7: Adjust the offset according to the thickness of the actual registration point device. In actual use, the registration point has a certain thickness, and the theoretical registration coordinates F(x, y, z) should be offset by a thickness s towards 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 rapid registration and positioning device for aircraft assembly requires capturing the UV coordinates of the corresponding position of the actual object in the camera after obtaining the theoretical registration coordinates during the matching process of virtual and real feature points. The accuracy of these coordinates greatly affects the accuracy of the matching. Therefore, this registration and positioning device was designed.

[0046] like Figures 4-7 As shown, the registration and positioning device mainly includes: a first registration part and a second registration part, the first registration part and the second registration part respectively including an adaptive fixator and a pin ring; one end of the adaptive fixator is provided with a pin ring, and the bottom of the adaptive fixator is provided with a insertion groove corresponding to the rib along the length direction. The middle part of the pin ring is provided with a concentric circular groove.

[0047] like Figure 6 and Figure 7 As shown, the adaptive retainer is placed on the rib and fixes the middle surface of the rib. A pin ring is inserted into the adaptive retainer to extend the middle surface position. The cross-plane coordinates are precisely positioned through the riveting arrangement between the concentric grooves of the two pin rings.

[0048] like Figure 8 As shown, the insertion slot has several stepped grooves corresponding to the rib. The adaptive positioner is mainly used to position the middle surface of the rib, and multiple stepped thicknesses are designed according to the actual use environment to meet the needs of different rib thicknesses. The slots on both sides are used to insert the two fixing feet protruding from the pin ring.

[0049] The pin ring is designed with two concentric circular grooves of different sizes, such as... Figure 5As shown, the concentric circular slots can be fitted together. The camera can obtain the UV coordinates of the pixel in the ring by identifying the center. To enhance the device's features and facilitate camera recognition, the pin ring of the first registration section is printed in white, and the pin ring of the second registration section is printed in black. This design results in the device appearing as a white circle with a black edge when fully fitted, significantly improving the camera's recognition success rate.

[0050] However, since its pin ring has a certain thickness, in actual use, the thickness of the pin ring should be added to the normal of its theoretical registration coordinates. In the method for quickly obtaining the theoretical registration coordinates of this patent, the normal of the surface can be obtained, and the theoretical registration coordinates after it is lifted can be automatically calculated according to the preset thickness.

[0051] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A rapid registration method for aircraft assembly, characterized by, A 3D STL model of the aircraft component is established, using the intersecting stiffeners on the frame beam of the aircraft component as virtual-to-real matching feature points; including the following steps: Step S1: Obtain the plane equation and the coordinates of a point on the plane; Based on any side plane of the intersecting stiffeners, obtain the plane equation R1 of the side plane of the stiffener: A1x + B1y + C1z + D1 = 0; Then, obtain the coordinates (x1, y1, z1) of any point P1 on the plane, and the straight line L1 that passes through point P1 and has the same direction as the normal to R1; Step S2: Find the opposite face of the rib in step S1; traverse all the triangular faces of the 3D STL model to obtain the plane equation R1_1 of the other face of the rib in step S1 and the coordinates of the intersection point P1_1; In step S2, the triangular face being searched satisfies: a) The normal direction is parallel to the plane equation R1; b) The intersection of line L1 and the triangular plane lies within the triangular plane; c) The projection distance d1 from the intersection point of line L1 and the triangular face to the plane equation R1 is the smallest, but not less than 1; Step S3: Calculate the equation of the middle surface of the rib in step S1; translate the plane equation R1_1 along the normal direction by a distance d = (d1 / 2) to obtain the middle surface equation R_Mid1; where: d1 is the projection distance of the intersection point of line L1 and the triangular face in step S2 from the plane equation R1. Step S4: Similarly, repeat steps S1 to S3 to obtain the equation R_Mid2 of the middle surface of the other rib. Step S5: Obtain the equation R_Top of the top plane of the intersecting stiffeners, with its normal vector being M(a, b, c); Step S6: Calculate the theoretical intersection point; combine the plane equations R_Mid1, R_Mid2 and the top plane equation R_Top to calculate the intersection point of the planes, which is used as the theoretical registration coordinate point F(x, y, z); Step S7: Adjust the offset according to the thickness of the physical registration point device; offset the theoretical registration coordinate point F(x, y, z) by the thickness s to 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 and assembly.

2. A quick registration positioning device for aircraft assembly based on the quick registration method for aircraft assembly according to claim 1, characterized in that, The system includes a first registration part and a second registration part, which are provided on the cross ribs on the corresponding frame beam. The first registration part and the second registration part respectively include an adaptive retainer and a pin ring. One end of the adaptive retainer is provided with a pin ring. The bottom of the adaptive retainer is provided with a insertion groove corresponding to the rib. The middle part of the pin ring is provided with a concentric circular groove corresponding to the aircraft assembly registration point.

3. A rapid registration positioning device for aircraft assembly according to claim 2, wherein, The insertion slot has several stepped grooves corresponding to the reinforcing bars.

4. The rapid registration positioning device for aircraft assembly of claim 2, wherein, A U-shaped frame is provided on one side of the pin ring, and the U-shaped frame is slidably inserted into the adaptive retainer.

5. A rapid registration positioning device for aircraft assembly according to claim 4, wherein, The adaptive fixer has several mounting grooves on both sides from top to bottom.

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