A novel multi-station measurement method for the shape of large-size composite material structural components for civil aircraft

Abstract

This invention belongs to the field of composite material assembly measurement technology, and discloses a novel multi-station measurement method for the shape of large-size civil aircraft composite material structural components. It utilizes a camera, a line structured light projector, a tracking camera, and positioning control points. Positioning control points are installed or affixed to the composite material structural component, and the camera, line structured light projector, and tracking camera are positioned to observe and track these control points. A global coordinate system is established based on the number and location of the control points. The line structured light projector projects structured light onto the surface of the composite material structural component. The camera, as the measurement unit, continuously captures images of the composite material structural component surface, obtaining images showing changes in reflected light. The phase difference is then calculated, determining the relative positional relationship between the camera and the composite material structural component, and calculating the coordinates of the composite material structural component surface in the global coordinate system. The tracking camera captures images of the composite material structural component surface, and the surface coordinates are input to obtain an image of the original connector group. The contour features of the original connector group image are extracted, and a three-dimensional structural contour feature is constructed based on the relative positional relationship between the tracking cameras. This invention is applicable to the assembly of multiple aircraft product sections, and has significant application value and economic benefits in reducing the number of shape inspections during assembly and lowering manufacturing costs.

Description

Technical Field

[0001] This invention belongs to the field of composite material assembly measurement technology, and relates to a measurement method in the assembly of large-size composite material structural parts, specifically a novel multi-station measurement method for the shape of large-size civil aircraft composite material structural parts. Background Technology

[0002] Civil aircraft extensively utilize composite material structures, which are often large in size, making measurement difficult, while also requiring high dimensional accuracy. Structural components include not only composite panels but also metal parts such as frames, beams, supports, connecting plates, and pressure plates. Because their structures are often delivered in segments, and parts require assembly before delivery, adjusting the panel profile on assembly fixtures involves repeatedly measuring the gaps between the panel and the clamping or positioning devices to ensure that the gaps at each position meet tolerance requirements. Without digital measuring equipment to provide data support during this adjustment process, the operation is cumbersome and time-consuming.

[0003] Furthermore, for large structural components, digital measuring equipment often needs to be adjusted multiple times to ensure measurement accuracy, impacting production efficiency. Custom-made, dedicated measuring equipment has extremely poor versatility, and changes in design necessitate changes to the measuring equipment as well, making cost a severe constraint.

[0004] Modern laser trackers, as the most common measurement system, generally consist of a laser ranging system, a laser angle measuring system, a control system, a dynamic measurement system, a laser receiver, a computer and measurement software, and a base. The measurement errors of laser trackers are mainly angle and distance measurement errors. Factors such as the laser receiver, the measurement environment, and the accuracy of the transfer station also affect measurement accuracy. For large structural components, a single measurement process cannot meet the requirements for measuring area, angle, and spatial position, often requiring multiple adjustments of the digital measuring equipment to ensure measurement results, thus impacting production efficiency. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides a novel multi-station measurement method for the shape of large-size composite material structural components for civil aircraft. Through flexible measurement, it aims to reduce the consumption of manpower and resources during the measurement process, lower manufacturing costs, and improve assembly efficiency.

[0006] The technical solution of the present invention is as follows:

[0007] A novel multi-station measurement method for the shape of large-size composite structural components for civil aircraft, using a camera, a line structured light projector, a tracking camera, and positioning control points, includes the following steps:

[0008] S1: Install or attach positioning control points on composite material structural components, and place the camera, line structured light projector, and tracking camera in a position that allows observation and tracking of the positioning control points;

[0009] S2: Establish a global coordinate system based on the number and location of the positioning control points;

[0010] S3: The control line structured light projector projects structured light onto the surface of the composite material structure. The camera is used as the measurement unit to continuously photograph the surface of the composite material structure. The image changes of the reflected light on the surface of the composite material structure are obtained, the phase difference is obtained, the relative position relationship between the camera and the composite material structure is obtained, and the coordinates of the surface of the composite material structure in the global coordinate system are calculated.

[0011] S4: Use a tracking camera to capture images of the surface of the composite material structure and input the coordinates of the surface of the composite material structure to obtain the original image of the connector group. Extract the contour features of the original image of the connector group and construct the three-dimensional structural contour features based on the relative positional relationship between the tracking cameras.

[0012] Furthermore, based on the size of the composite material structure to be tested and the field of view of the camera and the tracking camera, the number and location of positioning control points are determined to ensure the accuracy of the analysis; among them, the number of positioning control points is redundant.

[0013] Furthermore, in S4, the constructed three-dimensional structural contour features are calibrated using redundant positioning control points to obtain the final three-dimensional feature elements.

[0014] Furthermore, it also includes the use of a visual tracking standard frame, on which the tracking camera is mounted, and the visual tracking standard frame can finely adjust the position and shooting angle of the tracking camera.

[0015] Furthermore, there is one camera, one line structured light projector, two visual tracking standard frames, and two tracking cameras with a common measurement field of view.

[0016] Furthermore, the camera is mounted on a tripod, and a line structured light projector is mounted above the camera.

[0017] Furthermore, a camera is a camera with high recognition speed but relatively low accuracy, while a tracking camera is a camera with high accuracy but relatively low recognition speed.

[0018] Furthermore, in S3, the projected structured light is a sinusoidal stripe template image.

[0019] Furthermore, after completing one round of three-dimensional structural contour feature recognition, a mark is made at the location of the tracking camera to solidify the position of the tracking camera. In the next round of recognition of composite material structural parts of the same type, the tracking camera is placed directly at the marked position.

[0020] The beneficial effects of this invention are as follows:

[0021] 1. The novel multi-station shape measurement method for large-size composite material structural parts involved in this invention can be applied to the assembly of multiple aircraft product sections. It has great application value and economic benefits in reducing the number of shape inspections during the assembly process and reducing manufacturing costs.

[0022] 2. This invention can fix the measurement position, reduce the amount of calculation, reduce the actual measurement time, improve production efficiency, and provide a guarantee for efficient production. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this invention, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the multi-station measurement method of the present invention;

[0025] Among them, 1—camera, 2—line structured light projector, 3—visual tracking standard frame, 4—tracking camera, and 5—positioning control point. Detailed Implementation

[0026] This section describes embodiments of the present invention, used to explain and illustrate the technical solutions of the present invention. Unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0027] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating directions or positional relationships, are given in the accompanying drawings and are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or device referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include more than one of those features. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0028] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integrated connections; they can refer to mechanical connections or point connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0029] Example 1:

[0030] A novel multi-station measurement method for the shape of large-size composite structural components for civil aircraft, using camera 1, line structured light projector 2, tracking camera 4, and positioning control point 5, includes the following steps:

[0031] S1: Install or attach positioning control points 5 on the composite material structure, and place camera 1, line structured light projector 2, and tracking camera 4 in a position that can observe and track positioning control points 5;

[0032] S2: Establish a global coordinate system based on the number and location of positioning control points 5;

[0033] S3: Control line structured light projector 2 projects structured light onto the surface of composite material structure, and camera 1 is used as a measurement unit to continuously photograph the surface of composite material structure, obtain the image change of reflected light on the surface of composite material structure, obtain the phase difference, obtain the relative position relationship between camera 1 and composite material structure, and calculate the coordinates of the surface of composite material structure in the global coordinate system.

[0034] S4: Use tracking camera 4 to capture images of the surface of the composite material structure and input the coordinates of the surface of the composite material structure to obtain the original image of the connector group. Extract the contour features of the original image of the connector group and construct the three-dimensional structural contour features based on the relative positional relationship between the tracking cameras 4.

[0035] Based on the size of the composite material structure to be tested and the field of view of camera 1 and tracking camera 4, the number and location of positioning control points 5 are determined to ensure the accuracy of the analysis; among them, the number of positioning control points 5 is redundant.

[0036] In S4, the constructed three-dimensional structural contour features are calibrated using redundant positioning control points 5 to obtain the final three-dimensional feature elements.

[0037] It also includes the use of a visual tracking standard frame 3, on which a tracking camera 4 is mounted. The visual tracking standard frame 3 can finely adjust the position and shooting angle of the tracking camera 4.

[0038] Camera 1 consists of one unit, line structured light projector 2 consists of one unit, visual tracking standard frame 3 consists of two units, and tracking camera 4 with a common measurement field of view consists of two units.

[0039] Camera 1 is mounted on a tripod, and line structured light projector 2 is mounted above camera 1.

[0040] Camera 1 is a camera with high recognition speed but relatively low accuracy, while tracking camera 4 is a camera with high accuracy but relatively low recognition speed.

[0041] In S3, the projected structured light is a sinusoidal fringe template image.

[0042] After completing one round of three-dimensional structural contour feature recognition, a mark is made at the location of tracking camera 4 to solidify the position of tracking camera 4. In the next round of recognition of composite material structural parts of the same type, tracking camera 4 is placed directly at the marked position.

[0043] Example 2:

[0044] A novel multi-station measurement method for the shape of large-size composite material structural components for civil aircraft is presented, offering excellent measurement results and high safety and reliability. The main structure comprises a camera 1, a line structured light projector 2, a visual tracking standard frame 3, a tracking camera 4 with a common measurement field of view, and positioning control points 5.

[0045] By projecting structured light onto the object's surface, and based on the principles of 3D reconstruction, 3D point cloud data of the object's surface points in the coordinate system of the scanning measurement system is obtained. The visual tracking standard frame, as a component of the scanning measurement system, is designed as a three-dimensional structure to ensure that the tracking camera can recognize a sufficient number of effective poses during the measurement process. This enables the tracking and positioning sensor to track multiple viewpoints of the scanning measurement system. Positioning control points are used on the scanning measurement system. By identifying these control points and their spatial distribution, the transformation relationship between the tracking camera coordinate system and the coordinate system formed by the positioning control points is obtained, enabling the positioning of any pose of the scanning measurement system.

[0046] S1: Based on the size of the composite material structural component being measured, the field of view of the camera and the tracking camera, and by comprehensively analyzing efficiency and accuracy, determine the number and location of the positioning control points, ensuring that the field of view of the tracking positioning control points is not obstructed by the measured object or other surrounding workpieces, and determine the deployable area of ​​the structured light recognition camera 1 and the tracking camera 4.

[0047] S2: Establish a globally unified coordinate system based on the number and location of the positioning control points;

[0048] S3: By projecting structured light onto the surface of the object to generate a sinusoidal fringe template image, and using structured light recognition camera 1 as the measurement unit, the phase difference is obtained by utilizing the image changes during continuous shooting, and the relative positional relationship between camera 1 and composite material structure is further obtained.

[0049] S4: Using the preprocessed original connector group image of the tracking camera 4 with a common measurement field of view, extract the contour features of the original connector group image. Based on the relative positional relationship between the tracking cameras 4, construct the three-dimensional structural contour features of the composite material structure. Use redundant positioning control points for calibration to obtain the final three-dimensional feature elements.

[0050] The above description is merely a specific embodiment of the present invention, providing a detailed description of the invention. Parts not covered herein are conventional techniques. However, the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A novel multi-station measurement method for the external shape of large-size composite material structural components for civil aircraft, characterized in that, Using a camera (1), a line structured light projector (2), a tracking camera (4), and positioning control points (5), the following steps are included: S1: Install or attach positioning control points (5) on the composite material structure and place the camera (1), line structure light projector (2), and tracking camera (4) in a position that can observe and track the positioning control points (5); S2: Establish a global coordinate system based on the number and location of the positioning control points (5); S3: The control line structured light projector (2) projects structured light onto the surface of the composite material structure. The camera (1) is used as the measurement unit to continuously photograph the surface of the composite material structure. The image changes of the reflected light on the surface of the composite material structure are obtained, the phase difference is obtained, the relative position relationship between the camera (1) and the composite material structure is obtained, and the coordinates of the surface of the composite material structure in the global coordinate system are calculated. S4: Use the tracking camera (4) to capture the surface of the composite material structure and input the surface coordinates of the composite material structure to obtain the original image of the connector group. Extract the contour features of the original image of the connector group and construct the three-dimensional structure contour features based on the relative positional relationship between the tracking cameras (4).

2. The novel multi-station measurement method for the shape of large-size civil aircraft composite material structural components according to claim 1, characterized in that, Based on the size of the composite material structure to be tested, the field of view of the camera (1) and the tracking camera (4), the number and location of the positioning control points (5) are determined to ensure the accuracy of the analysis; among them, the positioning control points (5) have a redundant number.

3. A novel multi-station measurement method for the external shape of large-size civil aircraft composite material structural components according to claim 2, characterized in that, In S4, the constructed three-dimensional structural contour features are calibrated using redundant positioning control points (5) to obtain the final three-dimensional feature elements.

4. The novel multi-station measurement method for the shape of large-size civil aircraft composite material structural components according to claim 1, characterized in that, It also includes the use of a visual tracking standard frame (3), on which a tracking camera (4) is mounted. The visual tracking standard frame (3) can finely adjust the position and shooting angle of the tracking camera (4).

5. A novel multi-station measurement method for the external shape of large-size civil aircraft composite structural components according to claim 4, characterized in that, There is one camera (1), one line structured light projector (2), two visual tracking standard frames (3), and two tracking cameras (4) with a common measurement field of view.

6. A novel multi-station measurement method for the external shape of large-size civil aircraft composite material structural components according to claim 1, characterized in that, The camera (1) is mounted on a tripod, and the line structured light projector (2) is mounted above the camera (1).

7. A novel multi-station measurement method for the external shape of large-size civil aircraft composite structural components according to claim 1, characterized in that, Camera (1) is a camera with high recognition speed and relatively low precision, while tracking camera (4) is a camera with high precision and relatively low recognition speed.

8. A novel multi-station measurement method for the external shape of large-size civil aircraft composite material structural components according to claim 1, characterized in that, In S3, the projected structured light is a sinusoidal fringe template image.

9. A novel multi-station measurement method for the external shape of large-size civil aircraft composite material structural components according to claim 1, characterized in that, After completing one round of three-dimensional structural contour feature recognition, a mark is made at the location of the tracking camera (4) to solidify the position of the tracking camera (4). In the next round of recognition of composite material structural parts of the same type, the tracking camera (4) is placed directly at the marked position.

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