Digital measurement system and method for assembly quality of aircraft hydraulic expansion pipe

Abstract

The application provides an aircraft flared hydraulic conduit assembly quality digital measurement system and method, which comprises a flared conduit adapter target, a monocular photogrammetry camera, a binocular photogrammetry camera, a target ball, a non-coded mark point, a coded mark point, a scale, a data processing system and the like, the flared conduit adapter target is installed in the conduit, the axial line of the conduit and the position information of the flared end face can be indirectly obtained, the monocular photogrammetry camera establishes a global measurement field by shooting the target ball, the non-coded mark point and the scale, the coordinate value of the coded mark point in the aircraft coordinate system is obtained and transmitted to the binocular photogrammetry camera, the binocular photogrammetry camera shoots each flared conduit adapter target, the pose relationship is converted to the aircraft coordinate system, and the installation deviation of the conduit is obtained by comparing with the theoretical pose of the conduit. The flared end head pose information of the conduit after the positioning and installation of the aircraft part is detected, and the quality of the conduit and the pipe joint after the installation is indirectly predicted.

Description

Technical Field

[0001] This invention belongs to the field of aircraft assembly and inspection technology, and relates to a digital measurement system and method for the assembly quality of aircraft flared hydraulic conduits. Background Technology

[0002] In modern aerospace manufacturing, aircraft hydraulic conduits are key components of the aircraft hydraulic system, and their assembly quality directly affects flight safety and performance. The aircraft hydraulic system plays a crucial role in providing power and control to various aircraft components, and the precise assembly of hydraulic conduits is paramount. Hydraulic conduits mainly consist of a conduit body, a flared end, a flat nozzle, and a pipe fitting. One end of the conduit is flared at a 74° angle, with the flat nozzle contacting the outer conical surface of the conduit. The flared end fits against the inner conical surface of the conical pipe fitting connecting the two conduits, and is secured by a threaded connection. The outer conical surface of the pipe fitting contacts the inner conical surface of the flared conduit, forming a line seal for positioning. Screwing in increases preload, causing elastic deformation of the inner conical surface. As the force increases, the inner conical surface further undergoes plastic deformation, filling the gap between the inner and outer conical surfaces, ultimately achieving a seal. Currently, the positioning accuracy of hydraulic conduits is a key indicator for evaluating the quality of aircraft hydraulic conduits. Measurements primarily include three aspects: the gap between the inner surface of the conduit flare and the connector, and the positional and angular deviations between the conduit axis and the connector axis. Existing positioning accuracy relies on traditional measurement methods, such as manual measurement using mechanical gauges and templates, and can only be performed after the conduit and connector are connected. These methods are not only inefficient, but their accuracy is also greatly affected by human factors, making it difficult to meet the high-precision assembly requirements of modern aircraft. Furthermore, traditional measurement methods cannot obtain real-time quality data after conduit assembly, and deviations during the assembly process cannot be detected and corrected in a timely manner, leading to unstable assembly quality and increased assembly costs and timelines.

[0003] Therefore, to address the aforementioned issues, there is an urgent need to develop a digital measurement method for the assembly quality of aircraft hydraulic conduits. By detecting the positional information of the flared end after the conduit is positioned and installed, the quality of the conduit and pipe fittings after installation can be indirectly predicted. This would enable rapid and accurate measurement of the assembly positioning quality of aircraft hydraulic conduits, effectively improve assembly efficiency and quality, reduce assembly costs, and is of great significance to promoting the development of the aviation manufacturing field. Summary of the Invention

[0004] This invention provides a digital measurement method for the assembly quality of aircraft flared hydraulic conduits. It innovatively proposes a spatial orientation measurement process for aircraft hydraulic conduits and constructs an innovative and practical digital measurement system for the positioning deviation of aircraft hydraulic conduits. Using photogrammetry equipment, the system can quickly and accurately acquire the spatial position information of the hydraulic conduits. Furthermore, this invention designs a series of conduit connector adapter target structures, which can be quickly connected to the conduit to be measured, exhibiting good matching, simple structure, and high versatility and interchangeability. Combined with the digital measurement system, this further improves the accuracy and convenience of the measurement.

[0005] The present invention adopts the following technical solution:

[0006] A digital measurement system for the assembly quality of flared hydraulic conduits in aircraft is disclosed. This system is used to inspect the assembly quality of flared hydraulic conduits in aircraft components fixed to an assembly fixture. It includes a flared conduit adapter target 1, a monocular photogrammetry camera 3, a binocular photogrammetry camera 4, a target ball 7, non-coded marker points 9, coded marker points 10, a scale 11, and a data processing system. The flared conduit adapter target 1 is installed inside the conduit and can indirectly acquire information about the conduit axis and the position of the flared end face. The monocular photogrammetry camera 3 establishes a global measurement field by photographing the target ball 7, non-coded marker points 9, and scale 11, and acquires the aircraft coordinate system coordinates of the coded marker points 10, which are then transmitted to the binocular photogrammetry camera 4. The binocular photogrammetry camera 4 photographs each flared conduit adapter target 1, converts its positional relationship to the aircraft coordinate system, and compares it with the theoretical positional relationship of the conduit to obtain the conduit installation deviation.

[0007] The digital measurement system specifically includes a flared conduit adapter target 1, an adapter device 2, a monocular photogrammetric camera 3, a binocular photogrammetric camera 4, a collaborative robot 5, an AGV vehicle 6, a target ball 7, a target base 8, non-coded marker points 9, coded marker points 10, a scale 11, a tripod 12, and a data processing system.

[0008] The flared conduit adapter target 1 is installed at the flared joint of each conduit on the aircraft component, and the position of the conduit flared joint is indirectly obtained by measuring its spatial position. The flared conduit adapter target 1 includes a conduit position probe 1-1, a three-jaw chuck 1-2, an end polyhedron 1-3, a glass cover 1-4, and a reflective target 1-5.

[0009] The catheter pose probe 1-1 is used to connect with the catheter to be measured and transmit the catheter's axis and end-face pose information. It includes a coaxial axis probe 1-1-1, an end-face probe 1-1-2, a stud 1-1-3, and a tail shank 1-1-4. The axis probe 1-1-1 is a cylindrical guide pin with a diameter identical to the inner diameter of the catheter to be measured, thus enabling the acquisition of the catheter's axis pose. The end-face probe 1-1-2, located at the rear end of the axis probe 1-1-1, is a cylindrical boss with a diameter identical to the outer diameter of the catheter's flared end face. Its front end face is aligned with the flared end face of the catheter to be measured. The face contact is used to directly obtain the position information of the end face of the flared end of the catheter to be measured. The deviation of the position of this plane directly affects the gap value between the flared surface of the catheter and the conical surface of the connector. At the same time, this plane intersects with the axis of the axis probe 1-1-1. The obtained intersection point is used to evaluate the position deviation of the installation axis of the catheter to be measured. The stud 1-1-3 is located at the rear end of the end face probe 1-1-2 and is used to cooperate with the outer nut of the catheter to achieve a fixed connection. The tail shank 1-1-4 is located at the rear end of the stud 1-1-3. It is a cylinder and is used to clamp on the three-jaw chuck 1-2. Its diameter is 4 to 6 mm.

[0010] The three-jaw chuck 1-2 is a general-purpose component. The front end has three jaws and the rear end has a chuck body. The three jaws are evenly distributed along the circumference of the chuck body. The chuck body is used to screw or glue to the end polyhedron 1-3. The jaws are used to retract and clamp the tail shank 1-1-4 at the rear end of the catheter position probe 1-1. After clamping, the three-jaw chuck 1-2 is coaxial with the catheter position probe 1-1.

[0011] The aforementioned end polyhedron 1-3 is a spherical polyhedron made of plastic or metal with a dark surface. The included angle between each facet of the polyhedron is ≥45°, and the more faces there are, the easier it is to be identified by the binocular photogrammetry camera. A reflective target 1-5 is pasted at the center of each facet. The reflective target 1-5 is a highly reflective sticker with a diameter not greater than 20mm and a thickness of 0.1-0.2mm. The area of ​​each facet of the polyhedron must be larger than that of the reflective target 1-5. A glass cover 1-4 is pasted on each reflective target 1-5. The glass cover 1-4 is a transparent and colorless circular glass that can cover the entire reflective target 1-5 after installation. Its diameter is ≤20mm and its thickness is 1-2mm. It ensures light transmission while protecting the reflective sticker and preventing the reflective target 1-5 from becoming undetectable due to surface wear. Since re-pasting the reflective target 1-5 requires calibration of the entire flared guide tube adapter target 1, the glass cover 1-4 can save time and effort.

[0012] The target ball 7 is installed on the target base 8 of the assembly fixture. The target base 8 is an original component of the assembly fixture, originally used to install the optical target ball of the laser tracker. The center of the optical target ball of the laser tracker is used as the installation and debugging reference point of the tooling to establish the aircraft coordinate system. The target ball 7 is a general-purpose photogrammetric luminous target ball, and its diameter is the same as that of the optical target ball of the laser tracker. After installation, its center coincides with the center of the original optical target ball of the laser tracker, and is used to realize the coordinate system transformation through its coordinate values. In this way, the reference coordinate values ​​left during the debugging of the assembly fixture can be directly used to establish the aircraft coordinate system, avoiding the need to arbitrarily install the target base 8 and the target ball 7 and re-measure using the laser tracker, thus saving costs and time.

[0013] The non-coded marker point 9 is pasted on the frame surface of the assembly fixture for use as a transfer station for the binocular photogrammetric camera 4 in various local measurement fields.

[0014] The coded markers 10 are affixed to the frame surface of the assembly fixture and the surface of the aircraft parts for stitching together photos taken by the monocular photogrammetry camera 3.

[0015] There are two scales 11, which are arranged horizontally and vertically on the assembly fixture respectively. The scales 11 are connected to the assembly fixture by magnetic attraction and are used for proportional calibration, depth estimation and error control during the shooting process. The distance between the two scales 11 is as small as possible to ensure that the monocular photogrammetry camera 3 can capture both scales 11 at one time.

[0016] The AGV 6 is equipped with a collaborative robot 5, and a transfer device 2 is installed on its end flange. A monocular photogrammetry camera 3 is bolted to the transfer device 2. The AGV 6 and the collaborative robot 5 cooperate to realize multi-degree-of-freedom large-range relocation shooting by the monocular photogrammetry camera 3. The monocular photogrammetry camera 3 is used to photograph the target ball 7, non-coded marker point 9, and coded marker point 10 on the assembly fixture. The target ball 7 and non-coded marker point 9 are unified into a coordinate system. Then, the coordinate system is transformed by using the obtained coordinates of the center of the target ball 7 and the theoretical coordinates of the center of the target ball 7 to create a global measurement field in the aircraft coordinate system. The coordinate values ​​of the non-coded marker points after the coordinate transformation are then transmitted to the binocular photogrammetry camera 4.

[0017] The binocular photogrammetric camera 4 is mounted on a tripod 12 in the measurement field and is used to create a local measurement field in the aircraft coordinate system using the coordinate values ​​of the acquired non-coded marker points 9, and to measure the pose of the flared duct adapter target 1 that can be photographed within the local area.

[0018] The data processing system is equipped with image processing software, which is used to acquire images captured by the monocular photogrammetry camera 3 and the binocular photogrammetry camera 4, perform image stitching, coordinate system transformation, and obtain coordinates and position vectors, and finally obtain the duct installation error.

[0019] A digital measurement method for the assembly quality of aircraft flared hydraulic conduits, based on the aforementioned measurement system, includes the following steps:

[0020] Step 1: Check the positioning status of the aircraft parts on the assembly fixture to ensure the product is in a stable state; check and record the position of the hydraulic flared conduit exposed on the outside of the fuselage to ensure that the conduit is installed and fixed.

[0021] Step 2: Record the theoretical coordinate values ​​of the installation and debugging reference points on the assembly fixture frame, record the names and coordinate values ​​of the installation and debugging reference points, and input them into the data processing system for fitting the data captured by the monocular photogrammetry camera 3 and creating the aircraft coordinate system. Input the theoretical positions of the aircraft components, including the theoretical positions of the conduits on the aircraft components, into the data processing system; set up the binocular photogrammetry camera 4.

[0022] Step 3, Calibrate the flared tubing adapter target 1: Use a binocular photogrammetry camera 4 to calibrate each flared tubing adapter target 1 one by one. Specifically: Use the binocular photogrammetry camera 4 to photograph all reflective targets 1-5 on the flared tubing adapter target 1. The reflective targets 1-5 together form the pose frame of the flared tubing adapter target 1, where the centroid of all reflective targets 1-5 is the zero point of the flared tubing adapter target 1. Establish the tool coordinate system of the flared tubing adapter target 1 by arbitrarily selecting 3 reflective targets 1-5; on the axis Multiple points are selected on line probe 1-1-1 and end face probe 1-1-2 respectively. The handheld probe assembly of the binocular photogrammetry camera 4 is used to detect the selected points. The data processing system establishes the cylindrical and planar features of axis probe 1-1-1 and end face probe 1-1-2 in the tool coordinate system. Two axis points and three end face points are extracted from axis probe 1-1-1 and end face probe 1-1-2 respectively. These five points have a fixed pose relationship with the pose frame formed by the reflective target 1-5.

[0023] Step 4: Install the flared catheter adapter target 1 on each catheter connector one by one, ensuring that each catheter connector is equipped with the flared catheter adapter target 1. Enter the number of each flared catheter adapter target 1 and the corresponding catheter into the data processing system to avoid confusion.

[0024] Step 5: Install the target ball 7 on the target base 8 of the assembly fixture; install two rulers 11 on the assembly fixture; and attach coded markers 10 and non-coded markers 9 to the assembly fixture.

[0025] Step 6: Install the monocular photogrammetry camera 3 onto the end of the collaborative robot 5 on the AGV vehicle 6. Control the AGV vehicle 6 and the collaborative robot 5 to adjust the shooting position and angle of the monocular photogrammetry camera 3 to capture images of the scale 11, coded marker point 10, non-coded marker point 9, and target ball 7. The monocular photogrammetry camera 3 simultaneously identifies the coded marker point 10, non-coded marker point 9, and target ball 7. In the data processing system, the common coded marker point 10 of each image is used to stitch together the spatial positions to obtain the coordinate values ​​of the coded marker point 10 and the target ball 7. Then, the coordinate values ​​of the target ball 7 are used to perform coordinate system transformation with the tooling reference point coordinate values ​​to create a global measurement field in the aircraft coordinate system. The transformation of the aircraft coordinate system is then performed to obtain a set of coordinates of the non-coded marker point 9 in the aircraft coordinate system.

[0026] Step 7: Import the coordinate values ​​of the non-coded marker point 9 after coordinate transformation into the binocular photogrammetry camera 4. The binocular photogrammetry camera 4 captures the non-coded marker point 9 that can be identified within its installation position and compares it with the non-coded marker point 9 captured by the monocular photogrammetry camera 3. The relative positional relationship between the binocular photogrammetry camera 4 and the assembly fixture is calculated. Since the relative position between the aircraft component and the assembly fixture is fixed, the relative positional relationship between the binocular photogrammetry camera 4 and the aircraft component is indirectly obtained.

[0027] Step 8: The binocular photogrammetry camera 4 captures images of the flared duct adapter targets 1 installed at different locations. Each flared duct adapter target 1 captures at least 3 reflective targets 1-5. The data processing system can then calculate the spatial pose of each flared duct adapter target 1 in the aircraft coordinate system. The tool coordinate system of each flared duct adapter target 1 is converted to the aircraft coordinate system. Combining the pose relationship between the two axis points and the three end face points obtained in Step 3 and the pose frame of the flared duct adapter target 1, the coordinate values ​​of these 5 points in the aircraft coordinate system are calculated. A straight line is established using the two axis points and a surface is established using the three end face points. The surface is compared with the theoretical axis and end face of the corresponding duct to obtain the duct installation deviation and provide the pose adjustment parameters for the out-of-tolerance duct.

[0028] Step 9: After adjusting the out-of-tolerance catheter according to the pose adjustment parameters, measure and verify again until the positioning accuracy meets the requirements.

[0029] The beneficial effects of this invention are as follows: This invention solves the problem that the mass of hydraulic flared conduits for aircraft components cannot be quantified after positioning, leading to large deviations in axial position and angle relative to the orientation when connecting hydraulic system pipelines between components after subsequent large component docking, thus preventing effective connection and sealing. This invention indirectly predicts the mass of the conduit and pipe fitting after installation by detecting the orientation information of the flared end of the conduit after positioning and installation on the aircraft component. This enables rapid and accurate measurement of the assembly and positioning quality of aircraft hydraulic conduits, effectively improving assembly efficiency and quality, reducing assembly costs, and is of great significance to promoting the development of the aviation manufacturing field. Attached Figure Description

[0030] Figure 1 A schematic diagram of a digital measurement system for the assembly quality of aircraft flared hydraulic conduits.

[0031] Figure 2 This is a structural diagram of the target for the flared catheter transfer.

[0032] Figure 3 This is a schematic diagram of the installation of the flared catheter transfer target.

[0033] Figure 4 This is a schematic diagram of the catheter positioning probe.

[0034] Figure 5 Target structural feature points.

[0035] In the diagram: 1. Flared conduit adapter target; 2. Adapter device; 3. Monocular photogrammetric camera; 4. Binocular photogrammetric camera; 5. Collaborative robot; 6. AGV vehicle; 7. Target ball; 8. Target mount; 9. Non-coded marker point; 10. Coded marker point; 11. Scale; 12. Tripod; 1-1. Conduit pose probe; 1-2. Three-jaw chuck; 1-3. End polyhedron; 1-4. Glass cover; 1-5. Reflective target. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] A digital measurement system for the assembly quality of flared hydraulic conduits in aircraft is used to inspect the assembly quality of flared hydraulic conduits in aircraft components fixed on assembly fixtures. The system includes a flared conduit adapter target 1, an adapter device 2, a monocular photogrammetric camera 3, a binocular photogrammetric camera 4, a collaborative robot 5, an AGV vehicle 6, a target ball 7, a target base 8, non-coded marker points 9, coded marker points 10, a scale 11, a tripod 12, and a data processing system. Figure 1 .

[0038] The flared conduit adapter target 1 is installed at the flared connector of each conduit on the aircraft component, and the position of the conduit flared connector is indirectly obtained by measuring its spatial pose. The flared conduit adapter target 1 includes a conduit pose probe 1-1, a three-jaw chuck 1-2, an end polyhedron 1-3, a glass cover 1-4, and a reflective target 1-5, such as... Figure 2 .

[0039] The catheter position probe 1-1 is used to connect with the catheter to be measured and transmit the catheter's axis and end face position information. It is mounted on a three-jaw chuck 1-2 and is a machined part, including a coaxial axis probe 1-1-1, an end face probe 1-1-2, a stud 1-1-3, and a tail shank 1-1-4. Figure 4 The axial probe 1-1-1 is a cylindrical guide pin with the same diameter as the inner diameter of the catheter to be measured, thus obtaining the axial orientation of the catheter. The end face probe 1-1-2 is located at the rear end of the axial probe 1-1-1 and is a cylindrical boss with the same diameter as the outer diameter of the flared end face of the catheter. Its front end face fits against the flared end face of the catheter to be measured, and is used to directly obtain the position information of the flared end face of the catheter to be measured. The deviation of this plane position directly affects the gap value between the flared surface of the catheter and the conical surface of the pipe fitting. At the same time, this plane intersects with the axis of the axial probe 1-1-1, and the obtained intersection point is used to evaluate the position deviation of the installation axis of the catheter to be measured. The stud 1-1-3 is located at the rear end of the end face probe 1-1-2 and is used to cooperate with the outer nut of the catheter to achieve a fixed connection. The tail shank 1-1-4 is located at the rear end of the stud 1-1-3 and is a cylinder used to clamp on the three-jaw chuck 1-2. Its diameter is 4-6 mm.

[0040] The three-jaw chuck 1-2 is a general-purpose component. The front end has three jaws and the rear end has a chuck body. The three jaws are evenly distributed along the circumference of the chuck body. The chuck body is used to screw or glue to the end polyhedron 1-3. The jaws are used to retract and clamp the tail shank 1-1-4 at the rear end of the catheter position probe 1-1. After clamping, the three-jaw chuck 1-2 is coaxial with the catheter position probe 1-1.

[0041] The aforementioned end polyhedron 1-3 is a spherical polyhedron made of plastic or metal with a dark surface. The included angle between each facet of the polyhedron is ≥45°, and the more faces there are, the easier it is to be identified by the binocular photogrammetry camera. A reflective target 1-5 is pasted at the center of each facet. The reflective target 1-5 is a highly reflective sticker with a diameter not greater than 20mm and a thickness of 0.1-0.2mm. The area of ​​each facet of the polyhedron must be larger than that of the reflective target 1-5. A glass cover 1-4 is pasted on each reflective target 1-5. The glass cover 1-4 is a transparent and colorless circular glass that can cover the entire reflective target 1-5 after installation. Its diameter is ≤20mm and its thickness is 1-2mm. It ensures light transmission while protecting the reflective sticker and preventing the reflective target 1-5 from becoming undetectable due to surface wear. Since re-pasting the reflective target 1-5 requires calibration of the entire flared guide tube adapter target 1, the glass cover 1-4 can save time and effort.

[0042] The target ball 7 is installed on the target base 8 of the assembly fixture. The target base 8 is an original component of the assembly fixture, originally used to install the optical target ball of the laser tracker. The center of the optical target ball of the laser tracker is used as the installation and debugging reference point of the tooling to establish the aircraft coordinate system. The target ball 7 is a general-purpose photogrammetric luminous target ball, and its diameter is the same as that of the optical target ball of the laser tracker. After installation, its center coincides with the center of the original optical target ball of the laser tracker, and is used to realize the coordinate system transformation through its coordinate values. In this way, the reference coordinate values ​​left during the debugging of the assembly fixture can be directly used to establish the aircraft coordinate system, avoiding the need to arbitrarily install the target base 8 and the target ball 7 and re-measure using the laser tracker, thus saving costs and time.

[0043] The non-coded marker point 9 is pasted on the frame surface of the assembly fixture for use as a transfer station for the binocular photogrammetric camera 4 in various local measurement fields.

[0044] The coded markers 10 are affixed to the frame surface of the assembly fixture and the surface of the aircraft parts for stitching together photos taken by the monocular photogrammetry camera 3.

[0045] There are two scales 11, which are arranged horizontally and vertically on the assembly fixture respectively. The scales 11 are connected to the assembly fixture by magnetic attraction and are used for proportional calibration, depth estimation and error control during the shooting process. The distance between the two scales 11 is as small as possible to ensure that the monocular photogrammetry camera 3 can capture both scales 11 at one time.

[0046] The AGV 6 is equipped with a collaborative robot 5, and a transfer device 2 is installed on its end flange. A monocular photogrammetry camera 3 is bolted to the transfer device 2. The AGV 6 and the collaborative robot 5 cooperate to realize multi-degree-of-freedom large-range relocation shooting by the monocular photogrammetry camera 3. The monocular photogrammetry camera 3 is used to photograph the target ball 7, non-coded marker point 9, and coded marker point 10 on the assembly fixture. The target ball 7 and non-coded marker point 9 are unified into a coordinate system. Then, the coordinate system is transformed by using the obtained coordinates of the center of the target ball 7 and the theoretical coordinates of the center of the target ball 7 to create a global measurement field in the aircraft coordinate system. The coordinate values ​​of the non-coded marker points after the coordinate transformation are then transmitted to the binocular photogrammetry camera 4.

[0047] The binocular photogrammetric camera 4 is mounted on a tripod 12 in the measurement field and is used to create a local measurement field in the aircraft coordinate system using the coordinate values ​​of the acquired non-coded marker points 9, and to measure the pose of the flared duct adapter target 1 that can be photographed within the local area.

[0048] The data processing system is equipped with image processing software, which is used to acquire images captured by the monocular photogrammetry camera 3 and the binocular photogrammetry camera 4, perform image stitching, coordinate system transformation, and obtain coordinates and position vectors, and finally obtain the duct installation error.

[0049] A digital measurement method for the assembly quality of aircraft flared hydraulic conduits, based on the aforementioned measurement system, includes the following steps:

[0050] Step 1: Check the positioning status of the aircraft parts on the assembly fixture to ensure the product is in a stable state; check and record the position of the hydraulic flared conduit exposed on the outside of the fuselage to ensure that the conduit is installed and fixed.

[0051] Step 2: Record the theoretical coordinate labels of the installation and debugging reference points on the assembly fixture frame, record the names and coordinate values ​​of the installation and debugging reference points, and input them into the data processing system for fitting the data captured by the monocular photogrammetry camera 3 and creating the aircraft coordinate system. Input the theoretical positions of the aircraft components, including the theoretical positions of the ducts on the aircraft components, into the data processing system; set up the binocular photogrammetry camera 4. The binocular photogrammetry camera 4 only needs to capture one image of the flared duct adapter target 1 to calculate the required duct pose information, so its shooting efficiency is superior to that of the monocular photogrammetry camera. The advantage of the monocular photogrammetry camera is its high shooting accuracy, but its disadvantage is that it needs to capture dozens of images of a single target point, which is too inefficient.

[0052] Step 3, Calibrate the flared catheter adapter target 1: Use a binocular photogrammetry camera 4 to calibrate each flared catheter adapter target 1 one by one. Specifically: Use the binocular photogrammetry camera 4 to photograph all reflective targets 1-5 on the flared catheter adapter target 1. The reflective targets 1-5 together form the pose frame of the flared catheter adapter target 1, where the centroid of all reflective targets 1-5 is the zero point of the flared catheter adapter target 1. Establish the tool coordinate system of the flared catheter adapter target 1 by arbitrarily selecting 3 reflective targets 1-5; on the axis probe... Six points are selected on 1-1-1, and three points are selected on end face probe 1-1-2. The handheld probe assembly of the binocular photogrammetry camera 4 is used to probe the selected points. The data processing system establishes the cylindrical and planar features of axis probe 1-1-1 and end face probe 1-1-2 in the tool coordinate system. Two axis points and three end face points are extracted from axis probe 1-1-1 and end face probe 1-1-2 respectively. These five points have a fixed pose relationship with the pose frame formed by the reflective target 1-5, such as... Figure 5 .

[0053] Step 4: Install the flared catheter adapter target 1 onto each catheter connector one by one, such as... Figure 3 Ensure that each catheter connector is equipped with a flared catheter adapter target 1, and input the number of each flared catheter adapter target 1 and the corresponding catheter into the data processing system to avoid confusion.

[0054] Step 5: Install the target ball 7 on the target base 8 of the assembly fixture; install two rulers 11 on the assembly fixture; and attach coded markers 10 and non-coded markers 9 to the assembly fixture.

[0055] Step 6: Install the monocular photogrammetry camera 3 onto the end of the collaborative robot 5 on the AGV vehicle 6. Control the AGV vehicle 6 and the collaborative robot 5 to adjust the shooting position and angle of the monocular photogrammetry camera 3 to capture images of the scale 11, coded marker point 10, non-coded marker point 9, and target ball 7. The monocular photogrammetry camera 3 simultaneously identifies the coded marker point 10, non-coded marker point 9, and target ball 7. In the data processing system, the common coded marker point 10 of each image is used to stitch together the spatial positions to obtain the coordinate values ​​of the coded marker point 10 and the target ball 7. Then, the coordinate values ​​of the target ball 7 are used to perform coordinate system transformation with the tooling reference point coordinate values ​​to create a global measurement field in the aircraft coordinate system. The transformation of the aircraft coordinate system is then performed to obtain a set of coordinates of the non-coded marker point 9 in the aircraft coordinate system.

[0056] Step 7: Import the coordinate values ​​of the non-coded marker point 9 after coordinate transformation into the binocular photogrammetry camera 4. The binocular photogrammetry camera 4 captures the non-coded marker point 9 that can be identified within its installation position and compares it with the non-coded marker point 9 captured by the monocular photogrammetry camera 3. The relative positional relationship between the binocular photogrammetry camera 4 and the assembly fixture is calculated. Since the relative position between the aircraft component and the assembly fixture is fixed, the relative positional relationship between the binocular photogrammetry camera 4 and the aircraft component is indirectly obtained.

[0057] Step 8: The binocular photogrammetry camera 4 captures images of the flared duct adapter targets 1 installed at different locations. Each flared duct adapter target 1 captures at least 3 reflective targets 1-5. The data processing system can then calculate the spatial pose of each flared duct adapter target 1 in the aircraft coordinate system. The tool coordinate system of each flared duct adapter target 1 is converted to the aircraft coordinate system. Combining the pose relationship between the two axis points and the three end face points obtained in Step 3 and the pose frame of the flared duct adapter target 1, the coordinate values ​​of these 5 points in the aircraft coordinate system are calculated. A straight line is established using the two axis points and a surface is established using the three end face points. The surface is compared with the theoretical axis and end face of the corresponding duct to obtain the duct installation deviation and provide the pose adjustment parameters for the out-of-tolerance duct.

[0058] Step 9: After adjusting the out-of-tolerance catheter according to the pose adjustment parameters, measure and verify again until the positioning accuracy meets the requirements.

[0059] The above description is only a partial embodiment of the present invention and does not limit the implementation and protection scope of the present invention. Any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

1. A digital measurement method for the assembly quality of aircraft flared hydraulic conduits, characterized in that, This is based on a digital measurement system for the assembly quality of aircraft flared hydraulic conduits. The measurement system described above is used to inspect the assembly quality of flared hydraulic conduits in aircraft components fixed on assembly fixtures. The flared conduit adapter target (1) is installed inside the conduit and can indirectly obtain the position information of the conduit axis and the flared end face. The monocular photogrammetry camera (3) establishes a global measurement field in the aircraft coordinate system by shooting the target ball (7), the non-coded marker point (9), the coded marker point (10), and the scale (11). The binocular photogrammetry camera (4) shoots each flared conduit adapter target (1), converts its pose relationship to the aircraft coordinate system, and compares it with the theoretical pose of the conduit to obtain the conduit installation deviation. The measurement method includes the following steps: Step 1: Check the positioning of the aircraft parts on the assembly fixture, and check and record the location of the hydraulic flared conduits exposed on the outside of the fuselage. Step 2: Record the theoretical coordinate values ​​of the installation and debugging reference points on the assembly fixture frame, record the names and coordinate values ​​of the installation and debugging reference points, and input them into the data processing system. Input the theoretical positions of the aircraft components, including the theoretical positions of the ducts on the aircraft components, into the data processing system; set up a binocular photogrammetry camera (4). Step 3: Establish the tool coordinate system of the flared catheter transfer target (1), use a binocular photogrammetry camera (4) to calibrate the flared catheter transfer target (1), and obtain the pose relationship between its axis probe (1-1-1) and end face probe (1-1-2) and the pose frame of the flared catheter transfer target (1); Step 4: Install the flared catheter adapter target (1) on each catheter connector one by one, and input the number of each flared catheter adapter target (1) and the corresponding catheter into the data processing system to avoid confusion; Step 5: Install the target ball (7) on the assembly fixture; install two rulers (11) on the assembly fixture; paste coded markers (10) and non-coded markers (9) on the assembly fixture. Step 6: Use a monocular photogrammetry camera (3) to photograph the scale (11), coded marker points (10), non-coded marker points (9), and target sphere (7). The monocular photogrammetry camera (3) simultaneously identifies the coded marker points (10), non-coded marker points (9), and target sphere (7). In the data processing system, the common coded marker points (10) of each image are used to stitch together the spatial positions to obtain the coordinate values ​​of the coded marker points (10) and target sphere (7). Then, the coordinate values ​​of the target sphere (7) and the tooling reference point are used to perform coordinate system transformation to create a global measurement field under the aircraft coordinate system. The transformation of the aircraft coordinate system is then performed to obtain the coordinates of the non-coded marker points (9) under the aircraft coordinate system. Step 7: Import the coordinate values ​​of the non-coded marker points (9) after coordinate transformation into the binocular photogrammetry camera (4). The binocular photogrammetry camera (4) takes pictures of the non-coded marker points (9) that can be identified within its installation position, and compares them with the non-coded marker points (9) taken by the monocular photogrammetry camera (3). The relative positional relationship between the binocular photogrammetry camera (4) and the assembly fixture is calculated, and the relative positional relationship between the binocular photogrammetry camera (4) and the aircraft parts is indirectly obtained. Step 8: Use a binocular photogrammetry camera (4) to photograph the flared duct adapter targets (1) installed at different locations, and obtain the pose of each flared duct adapter target (1) in the aircraft coordinate system. The flared duct adapter target (1) includes a duct pose probe (1-1), a three-jaw chuck (1-2), an end polyhedron (1-3), and a reflective target (1-5). The duct pose probe (1-1) includes an axis probe (1-1-1) and an end face probe (1-1-2). Then, establish the axis position information of the axis probe (1-1-1) and the end face position information of the end face probe (1-1-2), compare them with the theoretical axis and end face of the corresponding duct, obtain the duct installation deviation, and give the pose adjustment parameters of the out-of-tolerance duct. Step 9: After adjusting the out-of-tolerance catheter according to the pose adjustment parameters, measure and verify again until the positioning accuracy meets the requirements.

2. The method for digitally measuring the assembly quality of aircraft flared hydraulic conduits according to claim 1, characterized in that, The flared catheter transfer target (1) includes a catheter pose probe (1-1), a three-jaw chuck (1-2), an end polyhedron (1-3), and a reflective target (1-5). The catheter pose probe (1-1) further includes a stud (1-1-3) and a tail shank (1-1-4), which are coaxial with the axis probe (1-1-1) and the end face probe (1-1-2). The axis probe (1-1-1) is a cylindrical guide pin with the same diameter as the inner diameter of the catheter to be measured, thus enabling the acquisition of the axial pose of the catheter. The end face probe (1-1-2) is located at the rear end of the axis probe (1-1-1) and is a cylindrical boss with the same diameter as the outer diameter of the flared end face of the catheter. Its front end face is in contact with the flared end face of the catheter to be measured, and is used to directly acquire the position information of the flared end face of the catheter to be measured. The stud (1-1-3) is located at the rear end of the end face probe (1-1-2) and is used to cooperate with the outer nut of the catheter to achieve a fixed connection. The tail shank (1-1-4) is located at the rear end of the stud (1-1-3) and is a cylinder. The front end of the three-jaw chuck (1-2) is a jaw, and the rear end is a chuck body. The chuck body is used to fix it to the end polyhedron (1-3), and the jaw is used to clamp the tail shank (1-1-4). After clamping, the three-jaw chuck (1-2) is coaxial with the catheter position probe (1-1). The end polyhedron (1-3) is a spherical polyhedron made of plastic or metal with a dark surface. The included angle between each face of the polyhedron is ≥45°, and a reflective target (1-5) is pasted at the center of each face.

3. The method for digitally measuring the assembly quality of aircraft flared hydraulic conduits according to claim 2, characterized in that, The end polyhedrons (1-3) are made of plastic or metal and have a dark surface.

4. The method for digitally measuring the assembly quality of aircraft flared hydraulic conduits according to claim 2, characterized in that, The reflective targets (1-5) mentioned above have a diameter of no more than 20 mm and a thickness of 0.1~0.2 mm.

5. The method for digitally measuring the assembly quality of aircraft flared hydraulic conduits according to claim 2, characterized in that, Each reflective target (1-5) is attached with a glass cover (1-4). The glass cover (1-4) is a transparent and colorless round glass. After installation, it can cover the entire reflective target (1-5), ensuring light transmission while protecting the reflective target (1-5).

6. The method for digitally measuring the assembly quality of aircraft flared hydraulic conduits according to claim 2, characterized in that, The target ball (7) is installed on the target base (8) of the assembly fixture. Its diameter and the center of the ball after installation are consistent with the optical target ball of the laser tracker, which serves as the installation and debugging reference point of the tooling. The non-coded marking point (9) is pasted on the frame surface of the assembly fixture, and the coded marking point (10) is pasted on the frame surface of the assembly fixture and the surface of the aircraft parts. There are two scales (11), which are arranged horizontally and vertically on the assembly fixture.

7. The method for digitally measuring the assembly quality of aircraft flared hydraulic conduits according to claim 2, characterized in that, The monocular photogrammetric camera (3) is mounted on the end of the collaborative robot (5) on the AGV vehicle (6) to adjust the shooting angle.

8. The method for digitally measuring the assembly quality of aircraft flared hydraulic conduits according to claim 2, characterized in that, Step 3 specifically involves: using a binocular photogrammetry camera (4) to photograph all reflective targets (1-5) on the flared catheter adapter target (1). The reflective targets (1-5) together form the pose frame of the flared catheter adapter target (1), where the centroid of all reflective targets (1-5) is the zero point of the flared catheter adapter target (1). Arbitrarily select 3 reflective targets (1-5) to establish the tool coordinate system of the flared catheter adapter target (1); and using the axis probe (1-1-1) and the end face probe (1... Multiple points are selected on the -1-2) respectively. The handheld probe component of the binocular photogrammetry camera (4) is used to detect the selected points. The data processing system establishes the cylindrical and planar features of the axis probe (1-1-1) and the end face probe (1-1-2) in the tool coordinate system. Two axis points and three end face points are extracted on the axis probe (1-1-1) and the end face probe (1-1-2) respectively. The pose relationship between the five points and the pose frame formed by the reflective target (1-5) is obtained.

9. A digital measurement method for the assembly quality of aircraft flared hydraulic conduits according to claim 8, characterized in that, Step 8 is as follows: Each flared tube adapter target (1) captures at least 3 reflective targets (1-5). The data processing system calculates the spatial pose of each flared tube adapter target (1) in the aircraft coordinate system. The tool coordinate system of each flared tube adapter target (1) is converted to the aircraft coordinate system. The pose relationship between the two axis points and the three end face points obtained in step 3 and the pose frame of the flared tube adapter target (1) is combined to calculate the coordinate values ​​of the five points in the aircraft coordinate system. A straight line is established using the two axis points and a surface is established using the three end face points to obtain the axis position information of the axis probe (1-1-1) and the end face position information of the end face probe (1-1-2).

Images