An aircraft large part measurement system and method

Abstract

The application discloses an airplane large-size part measuring system and method, and belongs to the technical field of digital measurement. The system comprises a part scanning mechanism, a positioning measuring mechanism and a laser tracker. The part scanning mechanism comprises a measuring terminal, and the positioning measuring mechanism comprises a truss positioner and a binocular measuring unit. A plurality of positioning measuring mechanisms are symmetrically arranged on the left and right sides of the measuring range of the part, and the part scanning mechanism is arranged on the front side or the rear side. The positioning measuring mechanism is used for positioning the measuring terminal based on the binocular vision positioning principle. The laser tracker is used for measuring the spatial coordinates of the ball centers of the target seats and the ground target markers, so that the coordinate system conversion relationship between the binocular measuring unit and the truss positioner and the coordinate system conversion relationship between the truss positioner and the global coordinate system are obtained. The application realizes the accurate measurement of the large-size part and the accurate positioning of the measurement data, and effectively improves the efficiency and the precision of the measurement.

Description

Technical Field

[0001] This invention belongs to the technical field of digital measurement, specifically relating to a measurement system and method for large-size aircraft parts. Background Technology

[0002] As aircraft design specifications become increasingly stringent, and in order to improve structural performance and reduce the use of connecting parts, aircraft components are gradually evolving towards integrated design, shifting from assemblies of multiple small parts to single, large components. This presents challenges for component quality inspection. The accuracy of conventional measuring equipment decreases as the size of the measured object increases, making traditional single-device measurements insufficient to meet the accuracy requirements of large-sized components.

[0003] To address the aforementioned issues, existing Chinese patent CN119958453A discloses a collaborative measurement method and system for a laser tracker and a 3D scanner, comprising the following steps: designing a 3D scanner fixture: designing a fixture and placing a target ball; transformation between the 3D scanner's measurement coordinate system and the fixture's coordinate system: calibrating the pose of the scanner's measurement coordinate system relative to the laser tracker's measurement coordinate system, i.e., the homogeneous transformation matrix; calibrating the pose of the laser tracker's measurement coordinate system relative to the fixture's coordinate system, i.e., the homogeneous transformation matrix; calibrating the pose of the scanner's measurement coordinate system relative to the fixture's coordinate system, i.e., the homogeneous transformation matrix; scanner fixture and equipment installation: installing the scanner fixture, and installing the laser tracker and laser scanner; workflow: using a collaborative measurement method for a laser tracker and a 3D scanner to perform high-precision measurement on large-size cylindrical products. This solution meets the measurement accuracy requirements for large-size parts, but it is still based on station-based measurement, requiring the measurement equipment to be transferred between different areas of the part, resulting in low efficiency. Furthermore, its design lacks consideration for the visibility of the laser tracker.

[0004] Chinese patent CN114413790A discloses a method and apparatus for large-field-of-view 3D scanning using a fixed photogrammetric camera. The method includes a laser 3D scanner and a high-precision photogrammetric camera. The laser 3D scanner consists of at least one camera and a laser projector, with supplementary lighting around all cameras. The method acquires the complete 3D topography of the workpiece with a large field of view by fixing a high-precision global measurement camera to the laser 3D scanner. First, global measurement control points are constructed, and the photogrammetric camera performs 3D reconstruction of these control points, establishing a global world coordinate system. Second, the laser 3D scanner acquires 3D point clouds of a local area surrounding the workpiece. Simultaneously, the fixed photogrammetric camera captures images, and the transformation relationship between the photogrammetric camera and the world coordinate system is obtained by observing the global measurement control points. Finally, the local 3D point cloud data is unified to the global coordinate system, completing the 3D scanning of the workpiece. This scheme uses an industrial camera mounted on the scanner to capture images of fixed marker points for scanner positioning. However, compared to a laser tracker, the industrial camera has limited accuracy, resulting in insufficient positioning accuracy over long distances. Summary of the Invention

[0005] The purpose of this invention is to provide a measurement system and method for large-size aircraft parts, aiming to solve the problems of low measurement accuracy and large positioning errors in measurement data caused by the large measurement space range when measuring large-size parts.

[0006] This invention is mainly achieved through the following technical solutions: A large-size aircraft part measurement system includes a part scanning mechanism, a positioning and measuring mechanism, and a laser tracker. The part scanning mechanism includes a measuring terminal with reflective markers. The positioning and measuring mechanism includes a truss positioner and a binocular measuring unit mounted on the truss positioner. Several target seats are respectively set at both ends of the truss positioner and within the measuring range. Ground targets are randomly distributed around the laser tracker for positioning.

[0007] Several positioning and measuring mechanisms are symmetrically arranged on the left and right sides of the measurement range of the part, and a part scanning mechanism is arranged on the front or rear side of the measurement range of the part. The positioning and measuring mechanism is used to capture the reflective marker points on the measuring terminal in real time based on the principle of binocular vision positioning in order to achieve positioning of the measuring terminal. The laser tracker is used to measure the spatial coordinates of the center of the target ball placed on the target base and the ground target to obtain the coordinate system transformation relationship between the binocular measuring unit and the truss positioner, as well as the coordinate system transformation relationship between the truss positioner and the global coordinate system.

[0008] To better realize the present invention, the part scanning mechanism further includes a three-dimensional motion mechanism and an execution terminal, and the execution terminal includes a robotic arm and a measuring terminal. The measuring terminal is connected to the three-dimensional motion mechanism through the robotic arm. The three-dimensional motion mechanism is used to drive the execution terminal to move along the X, Y and Z directions to scan and measure the part.

[0009] To better realize the present invention, the three-dimensional motion mechanism further includes an X-axis motion seat, a Y-axis motion seat, and a Z-axis motion seat, and the X-axis motion seat, Y-axis motion seat, and Z-axis motion seat are respectively provided with an X-axis slide rail, a Y-axis slide rail, and a Z-axis slide rail along the length direction; the top of the X-axis motion seat is slidably mounted with a Y-axis motion seat via an X-axis slide rail, the top of the Y-axis motion seat is slidably mounted with a Z-axis motion seat via a Y-axis slide rail, and a robotic arm is slidably mounted on the Z-axis motion seat via a Z-axis slide rail.

[0010] To better realize the present invention, the measuring terminal is further described as a laser scanner, a structured light scanner, or an industrial camera.

[0011] To better realize the present invention, further, columns are symmetrically arranged on the left and right sides of the measurement range of the part, and several positioning and measuring mechanisms are detachably installed on the columns from top to bottom, and the truss positioner is detachably connected to the column.

[0012] To better realize the present invention, the truss positioner further includes a hollow main body, a binocular measuring unit is installed inside the main body, and clearance spaces are provided at both ends of the main body corresponding to the scanning measuring ends of the binocular measuring unit; a plurality of target seats are provided at the left and right ends of the main body respectively.

[0013] To better realize the present invention, the upper, lower and left sides of the left end of the main body are respectively provided with a pyramid-shaped structure composed of support rods, and a target seat is provided at each corner of the pyramid-shaped structure. The structures at the left and right ends of the main body are symmetrically arranged.

[0014] To better realize the present invention, the length of the support rod of the pyramid-shaped structure at the left end of the main body is further: ; in: This refers to the side length of the support rod of the pyramid-shaped structure above; This refers to the side length of the support rod of the pyramid-shaped structure below; The side length of the support rod of the pyramid-shaped side structure; L The side length of the left end of the main body; aand b These are the global calibration station and the column position of the laser tracker, respectively. x Distance in direction and y Distance in the direction; h 1 represents the height of the positioning and measuring mechanism above the ground; h 2 represents the height of the laser tracker's measuring head from the ground.

[0015] A method for measuring large-sized aircraft parts, based on the aforementioned aircraft large-sized parts measurement system, includes the following steps: Step S1: Local calibration to obtain the coordinate transformation matrix T1 between the laser tracker and the binocular measurement unit, so as to clarify the coordinate system transformation relationship between the binocular measurement unit and the truss positioner; Step S2: Global calibration, obtain the coordinate transformation matrix T2 between the current laser tracker's coordinate system and the global coordinate system, and the coordinate transformation matrix T3 between the current laser tracker's coordinate system and the binocular measurement unit's coordinate system, so as to determine the coordinate system transformation relationship between the truss positioner and the global coordinate system; Step S3: Based on the coordinate system transformation relationship between the binocular measurement unit and the truss positioner, and the coordinate system transformation relationship between the truss positioner and the global coordinate system, map the scanning data of the measurement terminal to the global coordinate system; Step S31: Place the part within the measurement range, and then perform scanning measurement on the part using the measurement terminal; Step S32: Use a binocular measurement unit to measure and locate the reflective marker on the measurement terminal, obtain the coordinates J=T2·T3·H of the reflective marker in the global coordinate system, and finally map the scanning measurement data of the measurement terminal in step S31 to the global coordinate system; Where H is the coordinate of the reflective marker in the coordinate system of the binocular measurement unit.

[0016] To better implement the present invention, step S1 further includes the following steps: Step S11: Use laser tracker 5 to measure the spatial coordinates of the center of the laser tracker target ball placed on the target base within the measurement range of the positioning and measuring mechanism, and obtain the coordinate set A. n×3 ; Step S12: Use laser tracker 5 to measure the spatial coordinates of the center of the laser tracker target ball placed on the target mount of the positioning and measuring mechanism, and obtain the coordinate set B. m×3 ; Step S13: Replace the laser tracker target ball on the target holder within the measurement range with a photogrammetric target ball of the same size. Use a binocular measurement unit to measure the spatial coordinates of the center of the photogrammetric target ball placed on the target holder, and obtain the coordinate set C. n×3 ; Step S14: Based on coordinate set B m×3 and coordinate set C n×3 The coordinate transformation matrix T1 between the coordinate systems of the laser tracker and the binocular measurement unit is calculated using the least squares method. Then, the coordinate values ​​D of the target ball's center space coordinates on the truss positioner in the coordinate system of the binocular measurement unit are calculated. m×3 =T1·B m×3 .

[0017] To better realize the present invention, step S2 further includes the following steps: Step S21: Use laser tracker 5 to measure the spatial coordinates of the center of the target ball placed on the ground target 1, and obtain the coordinate set E. i×3 At this point, the coordinate system of laser tracker 5 is used as the global coordinate system. Step S22: For the positioning and measuring mechanism on the corresponding column, adjust the position of the laser tracker 5 to facilitate measuring the position of the target base on the truss positioner 10. Then, use the laser tracker 5 again to measure the spatial coordinates of the center of the target ball placed on the ground target 1, obtaining the coordinate set G. m×3 ; Step S23: Based on coordinate set E i×3 With coordinate set F i×3 The coordinate transformation matrix T2 between the coordinate system of the laser tracker at the current station and the global coordinate system in step S21 is calculated using the least squares method. Step S24: Based on coordinate set D m×3 With coordinate set G m×3 The coordinate transformation matrix T3 between the coordinate system of the laser tracker at the current station and the coordinate system of the binocular measurement unit is calculated using the least squares method.

[0018] The beneficial effects of this invention are as follows: This invention designs a serial positioning and transformation scheme, using a laser tracker as a calibration device for coordinate transformation parameters at each stage. This invention achieves precise measurement of large-sized parts and accurate positioning of measurement data, effectively improving measurement efficiency and accuracy. Specifically, this invention offers high measurement accuracy: Based on a binocular measurement unit, a truss locator, and a ground target, this invention achieves serial positioning and transformation, using a laser tracker as a calibration device for coordinate transformation parameters at each stage, effectively improving the accuracy of coordinate transformation. This invention also offers a large measurement range: This invention uses a three-dimensional motion mechanism equipped with a robotic arm, which can flexibly drive the measurement terminal to perform scanning measurements, better adapting to the measurement of large-sized parts. Furthermore, this invention offers high measurement efficiency: This invention eliminates the need for frequent station changes during the measurement process, enabling the part measurement to be completed in one go, avoiding the time spent on recalibration and improving measurement efficiency. Secondly, the truss locator design ensures that the camera is not obstructed, and the length of the support rod ensures that the corners of the pyramid-shaped structure meet the visibility requirements of the laser tracker, guaranteeing the accuracy of global calibration. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the aircraft large-size parts measurement system of the present invention; Figure 2 A schematic diagram of the connection structure between the robotic arm and the measuring terminal; Figure 3 This is a schematic diagram of the positioning and measuring mechanism; Figure 4 This is an exploded view of the positioning and measuring mechanism. Figure 5 An exploded view of the truss positioner; Figure 6 This is a schematic diagram of the positioning and measuring mechanism, the measuring range, and the laser tracker.

[0020] Among them: 1-Ground target, 2-X-axis motion seat, 3-Y-axis motion seat, 4-Z-axis motion seat, 5-Laser tracker, 6-Execution terminal, 7-Column, 8-Positioning and measuring mechanism, 9-Binocular measuring unit, 10-Truss positioner, 11-Robotic arm, 12-Measuring terminal, 13-Measuring range, 14-Target base, 15-Target ball. Detailed Implementation

[0021] Example 1: A measurement system for large aircraft parts, such as Figure 1As shown, the system includes: a ground target 1, a laser tracker 5, a part scanning mechanism, a column 7, and a positioning and measuring mechanism 8. The part scanning mechanism includes a three-dimensional motion mechanism and an execution terminal 6, and the execution terminal 6 includes a robotic arm 11 and a measuring terminal 12. The positioning and measuring mechanism 8 includes a truss positioner 10 and a binocular measuring unit 9, and the truss positioner 10 is detachably connected to the column 7. The ground target 1 is fixed to the workshop floor and is relatively randomly distributed; the ground target 1 is used for positioning by the laser tracker 5.

[0022] The measuring range 13 of the part is symmetrically provided with columns 7 on the left and right sides respectively. Several positioning and measuring mechanisms 8 are provided on the columns 7. The measuring range 13 of the part is provided with a part scanning mechanism on the front or rear side. The positioning and measuring mechanism 8 is used to capture the reflective marker points on the measuring terminal 12 in real time based on the principle of binocular vision positioning, so as to realize the positioning of the measuring terminal 12. The laser tracker 5 is used to measure the spatial coordinates of the center of the target ball 15 placed on the target base 14 and the ground target 1, so as to obtain the coordinate system transformation relationship between the binocular measuring unit 9 and the truss positioner 10 and the coordinate system transformation relationship between the truss positioner 10 and the global coordinate system.

[0023] like Figure 2 As shown, the measurement angle and distance can be controlled by the robotic arm 11 driving the measurement terminal 12; the measurement terminal 12 is equipped with reflective markers. Specifically, the measurement terminal 12 can be a laser scanner, a structured light scanner, or an industrial camera.

[0024] Preferably, such as Figure 1 As shown, the three-dimensional motion mechanism includes an X-axis motion seat 2, a Y-axis motion seat 3, and a Z-axis motion seat 4. The X-axis motion seat 2, Y-axis motion seat 3, and Z-axis motion seat 4 are respectively provided with X-axis slide rails, Y-axis slide rails, and Z-axis slide rails along their length directions. The top of the X-axis motion seat 2 is slidably mounted on the Y-axis motion seat 3 via the X-axis slide rail, and the top of the Y-axis motion seat 3 is slidably mounted on the Z-axis motion seat 4 via the Y-axis slide rail. A robotic arm 11 is slidably mounted on the Z-axis motion seat 4 via the Z-axis slide rail. Specifically, linear drive mechanisms (e.g., lead screw drive mechanisms) can be correspondingly provided on the X-axis motion seat 2, Y-axis motion seat 3, and Z-axis motion seat 4 to achieve automatic position control.

[0025] Specifically, the execution terminal 6 is mounted on the Z-axis slide rail and can slide along the Z-axis slide rail; the Z-axis motion seat 4 is mounted on the Y-axis slide rail and can slide along the Y-axis slide rail; the Y-axis motion seat 3 is mounted on the X-axis slide rail and can slide along the X-axis slide rail; the scanning range of the execution terminal 6 can be expanded through the cooperation of the above slide rails.

[0026] like Figure 3As shown, the positioning and measuring mechanism 8 is installed on the column 7, and its height on the column 7 can be adjusted according to measurement requirements. Multiple positioning and measuring mechanisms 8 can be configured according to the required measurement range 13. Secondly, when installing multiple positioning and measuring mechanisms 8, it is necessary to ensure that the measurement range 13 can cover the measured part, and that there is at least a 0.5m overlap between their boundaries. Since the positioning and measuring mechanism 8 needs to be calibrated periodically, the positioning and measuring mechanism 8 and the column 7 are connected in a detachable manner.

[0027] like Figure 4 As shown, the binocular measurement unit 9 is fixedly connected to the truss positioner 10; the binocular measurement unit 9 includes two cameras and a fixed structure in the middle, which is used to capture the reflective markers on the measurement terminal 12 in real time based on the binocular vision positioning principle, so as to realize the positioning of the measurement terminal 12.

[0028] Preferably, such as Figure 5 As shown, the main body of the truss locator 10 is a square truss structure. There are support rods at the top, bottom and four corners of the left frame of the main body, and pyramid-shaped structures are formed on the top, bottom and sides respectively. There is a target seat 14 at each corner of the pyramid-shaped structure.

[0029] The binocular measurement unit 9 has a single camera field of view of [missing information]. α The distance between the left side frame of the main body and the camera focal point along the truss in the direction of the camera's optical axis. d To ensure the truss does not obstruct the camera, the side length L of the left frame of the main structure needs to be greater than 2. d ×tan( α / 2).

[0030] To ensure global calibration accuracy, the corner points of the pyramid-shaped structure should meet the visibility requirements of the laser tracker 5 as much as possible. Therefore, the side length of the pyramid-shaped structure needs to be designed according to the installation position.

[0031] Among them, the height of the positioning and measuring mechanism 8 above the ground is h 1. The height of the measuring head of the laser tracker 5 above the ground is... h 2. The laser tracker 5 globally calibrates the station position and the column 7 in x The distance to the direction is a (Coordinate system as follows) Figure 1 (as shown) y The distance to the direction is b .

[0032] Based on the geometric occlusion relationship, the side length of the support rod of the pyramid-shaped structure above is derived. The side length of the support rod of the pyramid-shaped structure below Length of the side support rod of the pyramid-shaped structure Determine them according to the following formulas: ; The right side structure of the main body is similar to the left side structure, so it will not be described again. Compared to the left side structure, the only difference in the right side structure is the calculation formula for the side length of the support rod of the pyramid-shaped structure on the side. The side length of the support rod of the pyramid-shaped structure at the top of the right side frame of the main body... The side length of the support rod of the pyramid-shaped structure below Length of the side support rod of the pyramid-shaped structure Determine them according to the following formulas: .

[0033] Example 2: A method for measuring large aircraft parts, based on the aforementioned system, utilizes a gantry positioner 10 in conjunction with a laser tracker 5. Leveraging the high measurement accuracy of the laser tracker 5, a method of first local calibration and then global calibration is employed to accurately solve for the coordinate system transformation relationships between the binocular measurement unit 9 and the gantry positioner 10, and between the gantry positioner 10 and the global coordinate system. Finally, the scanned data is accurately mapped to the global coordinate system. The method includes the following steps: Step S1: Local calibration to obtain the coordinate transformation matrix T1 between the laser tracker 5 and the binocular measurement unit 9, so as to clarify the coordinate system transformation relationship between the binocular measurement unit 9 and the truss positioner 10; a. Use a standard to calibrate the binocular measurement unit 9 and the measurement terminal 12. The standard that comes with the selected equipment must be used during calibration. b. Figure 6 As shown, n target seats 14 are placed relatively uniformly within the measurement range 13 of the positioning and measuring mechanism 8, where n≥12. The laser tracker 5 is used to measure the spatial coordinates of the center of the target ball 15 placed on the target seat 14. Each position is measured k times and the average value is taken as the measurement result, where k≥10, to obtain the coordinate set A. n×3 ; c. Use a laser tracker 5 to measure the spatial coordinates of the centers of the target balls 15 placed on m target seats 14 on the truss positioner 10, where m ≥ 8. Measure each position k times and take the average value as the measurement result, where k ≥ 10, to obtain the coordinate set B. m×3 ; d. Replace the laser tracker target ball 15 on the target mount 14 with a photogrammetric target ball 15 of the same size. Use the binocular measurement unit 9 of the positioning measurement mechanism 8 to measure the spatial coordinates of the center of each photogrammetric target ball 15. Take the average value of each target ball 15 as the measurement result k times to obtain the coordinate set C. n×3 ; eA n×3 With C n×3To obtain the coordinates of the same set of points in both the laser tracker 5 coordinate system and the binocular measurement unit 9 coordinate system, the coordinate transformation matrix T1 between the laser tracker 5 coordinate system and the binocular measurement unit 9 coordinate system is calculated using the least squares method. This allows us to further obtain the coordinate values ​​D of the center of the target sphere 15 on the truss positioner 10 in the binocular measurement unit 9 coordinate system. m×3 =T1·B m×3 .

[0034] Step S2: Global calibration, obtain the coordinate transformation matrix T2 between the coordinate system of the current laser tracker 5 and the global coordinate system, and the coordinate transformation matrix T3 between the coordinate system of the current laser tracker 5 and the coordinate system of the binocular measurement unit 9, so as to determine the coordinate system transformation relationship between the truss positioner 10 and the global coordinate system. a. such as Figure 1 As shown, the spatial coordinates of the center of the target sphere 15 placed on the ground target 1 are measured using a laser tracker 5. There are i ground targets 1, i≥8, and each position is measured k times, with the average value taken as the measurement result, to obtain the coordinate set E. i×3 The coordinate system of laser tracker 5 in this state is taken as the global coordinate system. b. Install the positioning and measuring mechanism 8 on the column 7, adjust the position of the laser tracker 5 to a position that facilitates the measurement of the target base 14 on the truss positioner 10, and measure the spatial coordinates of the center of the target ball 15 placed on the ground target 1 again. The resulting coordinate set is F. i×3 The coordinates of the center of the target ball 15 placed by the truss positioner 10 are measured, and the resulting coordinate set is G. m×3 ; c. Referring to step e above, use E i×3 With F i×3 The coordinate transformation matrix T2 between the current station laser tracker's 5-coordinate system and the global coordinate system is calculated; using D m×3 With G m×3 The coordinate transformation matrix T3 between the coordinate system 5 of the laser tracker at the current station and the coordinate system 9 of the binocular measurement unit is calculated.

[0035] Based on the high measurement accuracy of the laser tracker 5 and the truss positioner 10, this invention employs a method of first local calibration and then global calibration, enabling the simultaneous use of multiple binocular measurement units 9 in the same measurement task, thus greatly improving the measurement range 13 and measurement accuracy. Specifically, this invention can achieve high-precision calibration of multiple binocular measurement units 9 in the same measurement field, unifying local coordinates to the global coordinate system with high precision.

[0036] Step S3: Based on the coordinate system transformation relationship between the binocular measurement unit 9 and the truss positioner 10, and the coordinate system transformation relationship between the truss positioner 10 and the global coordinate system, the scanning data of the measurement terminal 12 is mapped to the global coordinate system.

[0037] During measurement, the part is placed between two columns 7. Based on the cooperation between the robotic arm 11, the X-axis slide rail, the Y-axis slide rail, and the Z-axis slide rail, the measuring terminal 12 is driven to perform scanning measurement. The measuring terminal 12 is equipped with reflective markers.

[0038] At each measurement point, one or more binocular measurement units 9 locate the reflective marker. Let the coordinates of the reflective marker in the coordinate system of the binocular measurement unit 9 be H. Then, the coordinates of the reflective marker in the global coordinate system are J = T2·T3·H. If multiple binocular measurement units 9 locate the same measurement terminal 12, then J is the average of the coordinates calculated by the multiple binocular measurement units 9, achieving global positioning of the measurement terminal 12 and ultimately mapping the measurement data to the global coordinate system.

[0039] This invention designs a series positioning transformation scheme, using the laser tracker 5 as a calibration device for the coordinate transformation parameters of each link. This invention realizes the precise measurement of large-sized parts and the accurate positioning of measurement data, effectively improving the efficiency and accuracy of measurement.

[0040] 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 measurement system for large-size aircraft parts, characterized in that, The system includes a parts scanning mechanism, a positioning and measuring mechanism (8), and a laser tracker (5). The parts scanning mechanism includes a measuring terminal (12) with reflective markers. The positioning and measuring mechanism (8) includes a truss locator (10) and a binocular measuring unit (9) mounted on the truss locator (10). Several target seats (14) are provided at both ends of the truss locator (10) and within the measuring range (13). Ground targets (1) are randomly distributed around the laser tracker (5) and are used for positioning the laser tracker (5). Several positioning measurement mechanisms (8) are symmetrically arranged on the left and right sides of the measurement range (13) of the part, and a part scanning mechanism is arranged on the front or rear side of the measurement range (13) of the part; the positioning measurement mechanism (8) is used to capture the reflective markers on the measurement terminal (12) in real time based on the principle of binocular vision positioning, so as to realize the positioning of the measurement terminal (12); the laser tracker (5) is used to measure the spatial coordinates of the center of the target ball (15) placed on the target base (14) and the ground target (1) to obtain the coordinate system transformation relationship between the binocular measurement unit (9) and the truss positioner (10) and the coordinate system transformation relationship between the truss positioner (10) and the global coordinate system; The measuring range (13) of the part is symmetrically provided with columns (7) on the left and right sides respectively, and several positioning measuring mechanisms (8) are detachably installed on the columns (7) from top to bottom. The truss locator (10) is detachably connected to the column (7). The truss positioner (10) includes a hollow body, a binocular measuring unit (9) is installed inside the body, and the two ends of the body are respectively provided with clearance space corresponding to the scanning measuring end of the binocular measuring unit (9); a number of target seats (14) are respectively provided on the left and right ends of the body. The upper, lower and left sides of the left end of the main body are respectively provided with a pyramid-shaped structure composed of support rods, and a target seat (14) is provided at each corner of the pyramid-shaped structure. The structures at the left and right ends of the main body are symmetrically arranged. The length of the support rod of the pyramid-shaped structure at the left end of the main body is: ； in: This refers to the side length of the support rod of the pyramid-shaped structure above; This refers to the side length of the support rod of the pyramid-shaped structure below; The side length of the support rod of the pyramid-shaped side structure; L The side length of the left end of the main body; a and b The laser tracker (5) globally calibrated the station position and the column (7) respectively. x Distance in direction and y Distance in the direction; h 1 represents the height of the positioning and measuring mechanism (8) above the ground; h 2 represents the height of the measuring head of the laser tracker (5) from the ground.

2. The aircraft large-size parts measurement system according to claim 1, characterized in that, The part scanning mechanism includes a three-dimensional motion mechanism and an execution terminal (6). The execution terminal (6) includes a robotic arm (11) and a measuring terminal (12). The measuring terminal (12) is connected to the three-dimensional motion mechanism through the robotic arm (11). The three-dimensional motion mechanism is used to drive the execution terminal (6) to move along the X, Y and Z directions to scan and measure the part.

3. The aircraft large-size parts measurement system according to claim 2, characterized in that, The three-dimensional motion mechanism includes an X-axis motion seat (2), a Y-axis motion seat (3), and a Z-axis motion seat (4), and the X-axis motion seat (2), Y-axis motion seat (3), and Z-axis motion seat (4) are respectively provided with X-axis slide rail, Y-axis slide rail, and Z-axis slide rail along the length direction; the top of the X-axis motion seat (2) is slidably provided with the Y-axis motion seat (3) via the X-axis slide rail, the top of the Y-axis motion seat (3) is slidably provided with the Z-axis motion seat (4) via the Y-axis slide rail, and the Z-axis motion seat (4) is slidably mounted with a robotic arm (11) via the Z-axis slide rail.

4. A method for measuring large-size aircraft parts, implemented based on the large-size aircraft parts measurement system according to any one of claims 1-3, characterized in that, Includes the following steps: Step S1: Local calibration, obtain the coordinate transformation matrix T1 between the laser tracker (5) and the binocular measurement unit (9) to clarify the coordinate system transformation relationship between the binocular measurement unit (9) and the truss positioner (10); Step S2: Global calibration, obtain the coordinate transformation matrix T2 between the coordinate system of the current laser tracker (5) and the global coordinate system, and the coordinate transformation matrix T3 between the coordinate system of the current laser tracker (5) and the coordinate system of the binocular measurement unit (9), so as to determine the coordinate system transformation relationship between the truss positioner (10) and the global coordinate system; Step S3: Based on the coordinate system transformation relationship between the binocular measurement unit (9) and the truss locator (10) and the coordinate system transformation relationship between the truss locator (10) and the global coordinate system, the scanning data of the measurement terminal (12) is mapped to the global coordinate system; Step S31: Place the part within the measurement range (13), and then perform scanning measurement on the part through the measurement terminal (12); Step S32: Use a binocular measurement unit (9) to measure and locate the reflective marker on the measurement terminal (12), obtain the coordinates J=T2·T3·H of the reflective marker in the global coordinate system, and finally map the scanning measurement data of the measurement terminal (12) in step S31 to the global coordinate system; Where: H is the coordinate of the reflective marker in the coordinate system of the binocular measurement unit (9).

5. The method for measuring large-size aircraft parts according to claim 4, characterized in that, Step S1 includes the following steps: Step S11: Use a laser tracker (5) to measure the spatial coordinates of the center of the target ball (15) of the laser tracker (5) placed on the target base (14) within the measurement range (13) of the positioning and measuring mechanism (8), and obtain the coordinate set A. n×3 ; Step S12: Use a laser tracker (5) to measure the spatial coordinates of the center of the target ball (15) of the laser tracker (5) placed on the target mount (14) of the positioning and measuring mechanism (8), and obtain the coordinate set B. m×3 ; Step S13: Replace the laser tracker (5) target ball (15) on the target holder (14) within the measurement range (13) with a photogrammetric target ball (15) of the same size. Use a binocular measurement unit (9) to measure the spatial coordinates of the center of the photogrammetric target ball (15) placed on the target holder (14) to obtain the coordinate set C. n×3 ; Step S14: Based on coordinate set B m×3 and coordinate set C n×3 The coordinate transformation matrix T1 between the coordinate systems of the laser tracker (5) and the binocular measurement unit (9) is calculated using the least squares method. Then, the coordinate values ​​D of the center space coordinates of the target ball (15) on the truss positioner (10) in the coordinate system of the binocular measurement unit (9) are calculated. m×3 =T1·B m×3 .

6. The method for measuring large-size aircraft parts according to claim 5, characterized in that, Step S2 includes the following steps: Step S21: Use a laser tracker (5) to measure the spatial coordinates of the center of the target ball (15) placed on the ground target (1), and obtain the coordinate set E. i×3 At this point, the coordinate system of the laser tracker (5) is used as the global coordinate system. Step S22: For the positioning and measuring mechanism (8) on the corresponding column (7), adjust the position of the laser tracker (5) so that the laser tracker (5) can measure the spatial coordinates of the center of the target ball (15) placed on the ground target (1) again at the position of the target seat (14) on the truss locator (10), and obtain the coordinate set G. m×3 ; Step S23: Based on coordinate set E i×3 With coordinate set F i×3 The coordinate transformation matrix T2 between the coordinate system of the laser tracker (5) at the current station and the global coordinate system in step S21 is calculated using the least squares method. Step S24: Based on coordinate set D m×3 With coordinate set G m×3 The coordinate transformation matrix T3 between the coordinate system of the laser tracker (5) at the current station and the coordinate system of the binocular measurement unit (9) is calculated using the least squares method.

Images