Method for repairing damaged airplane by using high-precision vision measurement technology

Abstract

The invention provides a method for repairing a damaged airplane by using a high-precision vision measurement technology, and belongs to the technical field of aviation maintenance. The method comprises four important processes in a damaged airplane repairing process: manufacturing a special tool by using a reverse engineering technology, recovering a whole machine coordinate system by using a monocular vision technology, and carrying out accurate auxiliary installation of a frame plate by using a binocular vision real-time positioning technology. And the point cloud scanning technology is used for carrying out accurate comparison on the aerodynamic configuration so as to inspect the aerodynamic configuration repairing effect. The method gets rid of the traditional measurement concept of'tool-assisted and manual ', applies the digital vision technology, performs high-precision repair on the damaged aircraft under the condition of no original aircraft digital model, performs repair result verification, and realizes high-precision digital repair, so that the aircraft repair quality and the combat performance recovery are improved, and the maintenance cost is reduced. The method is suitable for repairing damaged machines with various pneumatic shape deformation and machine body structure damage, and the application effect is remarkable.

Description

Technical Field

[0001] The invention belongs to the technical field of aviation maintenance, and in particular relates to a method for repairing a damaged aircraft by utilizing high-precision visual measurement technology. Background Art

[0002] In the field of aviation repair, there are many cases where aircraft suffer structural damage during flight missions or other situations.

[0003] However, damaged aircraft still face the following difficulties during the damage repair process:

[0004] 1. When it is necessary to make a special surface tooling for a damaged aircraft with countless molds, there is no corresponding effective high-precision measurement method. Usually, it is measured step by step manually using a ruler, resulting in a large cumulative error and poor stability. If it is done by surface casting, a lot of manpower, material resources and time will be spent in the process of process execution.

[0005] 2. At present, the commonly used method for measuring horizontal points in the field of aircraft repair is theodolite horizontal mark point measurement. It requires one person to manually press the starting position of the tape measure to the horizontal point position at the position of the horizontal point to be measured, and the tape measure hangs naturally. The measurement needs to be carried out in a windless environment as much as possible, and the hand must be steady to ensure that the drooping tape measure does not swing or vibrate significantly. In addition, in the case of insufficient light, one person needs to hold a flashlight and shine it on the position of the ruler to be observed by the theodolite, and another person manually adjusts the theodolite to make it horizontal, aligns the ruler through the observer, and manually focuses until the scale of the ruler is clearly visible, reads the number, and counts it in the book to facilitate subsequent calculations. The above process is a method for measuring a horizontal point. After measuring other horizontal points, it is often necessary to manually calculate the position relationship between the two points to determine whether the aircraft is in a horizontal position. The existing measurement method will have a large number of artificial cumulative measurement errors, and it is necessary to first level the plane and then measure whether each point on the aircraft meets the standard. At the same time, it has high requirements for the working environment.

[0006] 3. When replacing a damaged frame plate, it is necessary to assemble it on the basis of an intact frame. Currently, there is no effective high-precision real-time equipment, and the trial-and-error method of repeated assembly and repeated measurement, that is, the trial-and-error method, is still used, which causes a huge waste of manpower and time.

[0007] 4. Currently, there is no effective high-precision scanning method for the aerodynamic shape of the aircraft after repair. Usually, the key horizontal measurement points are taken on the relevant surface, and the calculation is performed manually through observation with a hanging ruler and theodolite. This method is greatly affected by the environment. There will be errors in the hanging point of the manual hanging ruler, and there will be errors in the observation readings of the theodolite. It is impossible to take into account every point, and it cannot be operated in a windy environment. There are great constraints and large cumulative errors. Summary of the invention

[0008] In order to solve the repair measurement problem in the field of damaged aircraft and the shortcomings of the existing technology, the present invention provides a method for repairing a damaged aircraft using high-precision visual measurement technology, achieving high-precision, real-time, and visual measurement, thereby restoring the combat performance of the repaired aircraft.

[0009] The present invention adopts the following technical solution:

[0010] A method for repairing a damaged aircraft using high-precision visual measurement technology, the method for repairing a damaged aircraft comprising the following steps:

[0011] Step 1: Use reverse engineering technology to make conformal support tooling:

[0012] Step 1.1: Mark the damaged aircraft surface with marking points and coding points where support is required.

[0013] Step 1.2: To ensure high measurement accuracy, first use a monocular measuring device to photograph the damaged aircraft surface and calculate the surface space coordinate system.

[0014] Step 1.3: Scan with a portable scanner to finally form a point cloud model and perform micro post-processing.

[0015] Step 1.4: Measure the surface of the micro-post-processed point cloud model, obtain the size of the surface, and then generate a three-dimensional model for making a conformal support fixture, so that the gap between the conformal support fixture and the skin is no more than 0.5mm, to ensure that the skin at the bottom of the frame can be fixed to the original position after the surrounding structural parts are decomposed, and the skin contour does not deform or change position.

[0016] Step 1.5: Fix and keep the damaged aircraft in a horizontal parking state, and use conformal support fixtures to ensure that the bottom skin of the frame can be fixed in the original position after the surrounding structural parts are disassembled.

[0017] Step 2: Use monocular vision technology to restore the coordinate system of the entire machine:

[0018] Step 2.1: Place a measuring ruler on the back of the machine or on a stable surface.

[0019] Step 2.2: Post marking points at each horizontal measurement point, and use the marking points to enclose different patterns at different parts of the damaged aircraft to quickly identify the aircraft parts.

[0020] Step 2.3: Post coding points on the entire machine. The principle of posting coding points is to keep the number as small as possible while covering the entire machine. You can use tooling appropriately to post coding points on the tooling to transition to the back of the machine.

[0021] Step 2.4: Use a monocular vision device to take photos around the aircraft and ensure that there are at least three coded points with the same number in two adjacent photos.

[0022] Step 2.5: Calculate and form the aircraft's entire coordinate system.

[0023] Step 2.6: Take the nose vertebra apex as the zero point to analyze and obtain the position of each horizontal point of the damaged aircraft, so as to determine whether the left and right T13, 14, and 15 points of the repaired inlet lip meet the position requirements.

[0024] Step 3: Use binocular vision real-time positioning technology to accurately position and install the frame:

[0025] Step 3.1: Post the coding points and marking points on the frame to be installed and perform the initial installation of the frame.

[0026] Step 3.2: Use the binocular vision measurement system to continuously photograph the frame plate and the surrounding aircraft body, import them into the whole aircraft coordinate system, and obtain the real-time position relationship of the frame plate in the whole aircraft coordinate system.

[0027] Step 3.3: Continue to fine-tune the position of the frame, and use the binocular vision measurement system to monitor the position of the frame, and finally achieve precise installation positioning.

[0028] Step 4: Use point cloud scanning technology for precise comparison to verify the effect of aerodynamic shape repair.

[0029] Step 4.1: After the damaged aircraft is repaired, the repaired aerodynamic shape needs to be inspected and marking points and coding points must be posted inside and outside the air inlet.

[0030] Step 4.2: Use a monocular vision measurement device to photograph the air inlet and integrate the obtained marked point cloud into the whole aircraft coordinate system.

[0031] Step 4.3: Scan the marked points in the whole aircraft coordinate system, including the inner barrel and outer side of the left and right air inlets, and obtain the point cloud images of the two air inlets.

[0032] Step 4.4: Calculate and obtain the aerodynamic shape comparison diagram of the repaired air inlet and the intact air inlet. If one of the two air inlets of the damaged aircraft is intact and the other is the repaired air inlet, the point cloud of the intact air inlet is mirrored with the aircraft center axis plane, and finally the aerodynamic shape comparison diagram of the repaired air inlet and the intact air inlet is obtained; if both air inlets of the damaged aircraft are repaired air inlets, the point cloud of the intact air inlet is imported to obtain the aerodynamic shape comparison diagram of the two air inlets.

[0033] Step 4.5: Obtain the aerodynamic shape concave-convex difference map through the aerodynamic shape comparison map to verify whether the aerodynamic shape of the repaired air inlet is qualified.

[0034] Step 4.6: Analyze multiple cross-sections of the air inlet to see if the position relationship of the air inlet on the same horizontal plane of each section is qualified. The aerodynamic shape of the cockpit part can also be scanned and compared with the intact cockpit aerodynamic shape to check whether the repair effect meets the standard.

[0035] Step 5: After the repair effect is verified to be qualified, it is handed over to the next process and transferred for test flight.

[0036] Beneficial effects of the present invention:

[0037] (1) The reverse engineering modeling design technology pioneered the development of conformal support tooling, so that the gap between the tooling and the skin is no more than 0.5 mm, ensuring that the skin at the bottom of the frame can be fixed to the original position after the surrounding structural parts are decomposed, and the skin contour does not deform or change position. This effectively solves the current situation where the corresponding support tooling cannot be made according to the shape during the repair process of a damaged machine without a three-dimensional digital model.

[0038] (2) The monocular vision measurement method is specially developed for damaged machine repair. It has high measurement accuracy and can perform human-computer interaction through point cloud position arrangement. It has a high degree of visualization and is not affected by the error accumulation of manual hanging rulers or air flow.

[0039] (3) The binocular vision measurement method is specially developed for damaged machine repair. It has the characteristics of high real-time performance, good human-computer interaction, high measurement accuracy, and good flexibility. It effectively solves the current situation that there is no high-precision real-time positioning and measurement method for the frame plates of damaged machine repair.

[0040] (4) The aerodynamic shape comparison method is specially developed for the repair of damaged machines. It has the characteristics of good human-machine interaction and high measurement accuracy. It effectively solves the problem that it is impossible to verify with high accuracy whether the aerodynamic shape of a damaged machine meets the standards after repair.

[0041] (5) The present invention is used for aircraft damage repair. It adopts a digital repair method. After determining a complete measurement plan and location, customized fine-tuning can be performed according to the damage of each aircraft to achieve effective high-precision measurement.

[0042] (6) The present invention is applicable to the reverse production of tooling for damaged aircraft repair, the spatial position relationship of aircraft horizontal point measurement points, the high-precision real-time positioning and installation of aircraft frame panels, and the point cloud comparison of aircraft aerodynamic shapes, and is widely used in the field of damaged aircraft repair. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 is a flow chart of the method of the present invention; DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the specific implementation methods of the present invention will be described in detail below with reference to the technical solution.

[0045] The specific implementation of the present invention is further explained below in conjunction with the examples and drawings, but is not intended to limit the present invention.

[0046] like Figure 1 As shown, a method for repairing a damaged aircraft using high-precision visual measurement technology includes the following steps:

[0047] Step 1: Use reverse engineering technology to create conformal support tooling:

[0048] Step 1.1: Post coding points and marking points on the damaged aircraft surface where support is required, that is, the surface to be attached to the tooling.

[0049] Step 1.2: To ensure high measurement accuracy, first use a monocular measurement device to photograph the damaged aircraft surface, and then calculate the surface space coordinate system through splicing using the MPS industrial photogrammetry system software. Step 1.3: Import the surface space coordinate system into the scanning software Scan Viewer, scan it using a portable scanner, and finally form a point cloud model. The point cloud model is then processed using the software TViewer, including removing miscellaneous edges and flash.

[0050] Step 1.4: Then use the software Tviewer to measure the surface. After obtaining the size of the surface, use the 3D drawing software to generate a 3D model for the production and processing of conformal support tooling, so that the gap between the conformal support tooling and the skin is no more than 0.5mm, ensuring that the skin at the bottom of the frame can be fixed to the original position after the surrounding structural parts are decomposed, and the skin contour does not deform or change position.

[0051] Step 1.5: Use a fixing fixture to fix the damaged aircraft and keep it in a horizontal parking state, and use a conformal support fixture to ensure that the bottom skin of the frame can be fixed to the original position of the aircraft after the surrounding structural parts are disassembled.

[0052] Step 2: Use monocular vision technology to restore the coordinate system of the entire machine:

[0053] Step 2.1: Place a measuring ruler on the back of the machine or on a stable surface.

[0054] Step 2.2: Post marking points at each horizontal measurement point, and use the marking points to enclose different patterns at different parts of the damaged aircraft to quickly identify the aircraft parts.

[0055] Step 2.3: Post coding points on the entire machine. The principle of posting coding points is to keep the number as small as possible while covering the entire machine. Record the numbering range of the coding points to prevent duplication when adding coding points later. Also post coding points on fixed tooling to transition to the back of the machine.

[0056] Step 2.4: Use a monocular vision device to shoot around the aircraft. The shooting movement is required to cover every horizontal point on the aircraft that needs to be measured, and ensure the continuity of the shooting route. Each photo has at least three identical coding points with the previous photo. When shooting, you should shoot in a combination of horizontal and vertical shooting to increase the maximum shooting connection range of the position, and combine the shooting method of standing up, middle and down. The marked points are recorded in the camera through the flash, and finally the analysis software is informed of the location of the point. Especially in the transition from the lower fuselage to the back of the aircraft, there needs to be a smooth transition connection path of coding points and visual inspection. If there is no better natural connection method, an effective transition is made by pasting coding points on the immovable auxiliary tooling.

[0057] Step 2.5: Use MPS industrial photogrammetry system software to calculate the entire aircraft coordinate system.

[0058] Step 2.6: Use Spatial Analyzer software to intuitively obtain the positional relationship between each horizontal point of the aircraft, obtain the best fitting spatial coordinate system through splicing and other algorithms, weighting and other methods, import the theoretical coordinate system zero point, restore the whole aircraft coordinate system through the best fitting, and use the nose vertebra vertex as the zero point to analyze the position of each horizontal point, the distance between each horizontal point, and the distance from the horizontal point to the horizontal plane of the aircraft, so as to analyze whether the position of each horizontal point meets the standard. For example, it can be concluded whether the left and right T13, 14, and 15 horizontal measurement points of the inlet lip after repair meet the position requirements.

[0059] Step 3: Use binocular vision real-time positioning technology to accurately position and install the frame:

[0060] Step 3.1: Post marking points and coding points on the frame panels that need to be positioned, such as on the upper and lower wall panels of a frame. The posting requirement is to post as few points as possible while covering the entire panel surface. Perform the initial installation of the upper and lower wall panels of a frame.

[0061] Step 3.2: Ensure that the binocular measurement equipment has a good shooting angle to obtain complete overall values. Import the whole aircraft coordinate system into the MPS real-time industrial photogrammetry system, and use the binocular measurement equipment to continuously shoot a frame of upper and lower wall panels and the surrounding body to obtain the real-time position relationship of a frame of upper and lower wall panels in the whole aircraft coordinate system. The pictures taken must include at least 3 coded points posted on the damaged aircraft in step 2.

[0062] Step 3.3: Continue to fine-tune the position of the upper and lower wall panels of a frame, and use the binocular vision measurement system to monitor the position of the frame panels, ultimately achieving precise installation positioning.

[0063] Step 4: Use point cloud scanning technology to inspect the aerodynamic shape repair effect.

[0064] Step 4.1: After the damaged aircraft is repaired, the repaired aerodynamic shape needs to be inspected and marking points and coding points must be posted inside and outside the air inlet.

[0065] Step 4.2: Use a monocular vision measurement device to photograph the air inlet and integrate the obtained marked point cloud into the whole aircraft coordinate system.

[0066] Step 4.3: Scan the marked points in the whole aircraft coordinate system, including the inner barrel and outer side of the left and right air inlets, and obtain the point cloud images of the two air inlets.

[0067] Step 4.4: Import the point cloud image into TViewer software for analysis. In this embodiment, the left air inlet is a complete air inlet, and the right air inlet is a repaired air inlet. The left air inlet is mirrored according to the center plane of the aircraft using TViewer software, and an overlapping point cloud is obtained at the right air inlet, thereby obtaining a comparison diagram of the aerodynamic shape of the right air inlet.

[0068] Step 4.5: By analyzing the aerodynamic shape comparison diagram through software, the aerodynamic shape concave-convex difference diagram can be intuitively obtained to verify whether the aerodynamic shape of the repaired right air inlet is qualified.

[0069] Step 4.6: Analyze multiple cross-sections of the air inlet to see if the position relationship of the air inlet on the same horizontal plane of each section is qualified. The aerodynamic shape of the cockpit part can also be scanned and compared with the intact cockpit aerodynamic shape to check whether the repair effect meets the standard.

[0070] Step 5: After the visual measurement analysis is verified to be qualified, it is delivered to the next process, transferred for test flight, and the aircraft is delivered. The measurement results can also be delivered in the form of a data package or technical report.

Claims

1. A method for repairing a damaged aircraft using high-precision visual measurement technology, characterized in that: The method for repairing a damaged aircraft comprises the following steps: Step 1: Use reverse engineering technology to make conformal support tooling: Step 2: Use monocular vision technology to restore the coordinate system of the entire machine: Step 3: Use binocular vision real-time positioning technology to accurately position and install the frame: Step 4: Use point cloud scanning technology for precise comparison to verify the effect of aerodynamic shape repair; Step 5: After the repair effect is verified to be qualified, it is delivered to the next process.

2. A method for repairing a damaged aircraft using high-precision visual measurement technology according to claim 1, characterized in that: The step 1 is specifically as follows: Step 1.1: Mark the damaged aircraft surface with marking points and coding points where support is needed; Step 1.2: Use a monocular measuring device to photograph the damaged aircraft surface and calculate the surface space coordinate system; Step 1.3: Scan with a portable scanner to form a point cloud model; Step 1.4: Measure the surface of the point cloud model and generate a three-dimensional model for making a conformal support tooling. The conformal support tooling is used to ensure that the bottom skin of the frame does not deform or change position. Step 1.5: Secure and maintain the damaged aircraft in a horizontal parking state and support it using conformal support fixtures.

3. The method for repairing a damaged aircraft using high-precision visual measurement technology according to claim 1, characterized in that: The step 2 is specifically as follows: Step 2.1: Place a measuring ruler on the back of the machine or on a stable surface; Step 2.2: Post a marking point at each horizontal measurement point; Step 2.3: Post code points on the entire machine; Step 2.4: Use a monocular vision device to take pictures around the aircraft; Step 2.5: Calculate and form the aircraft's entire coordinate system; Step 2.6: Take the nose vertebra apex as the zero point to analyze and obtain the position of each horizontal point of the damaged aircraft.

4. The method for repairing a damaged aircraft using high-precision visual measurement technology according to claim 3 is characterized in that: In the step 2.2, different patterns are enclosed by marking points at different damaged parts of the aircraft to quickly identify the parts of the aircraft.

5. The method for repairing a damaged aircraft using high-precision visual measurement technology according to claim 3 is characterized in that: In the step 2.4, there are at least three code points with the same number in two adjacent photos.

6. The method for repairing a damaged aircraft using high-precision visual measurement technology according to claim 1, characterized in that: The step 3 is specifically as follows: Step 3.1: Post the coding points and marking points on the frame to be installed, and perform the initial installation of the frame; Step 3.2: Use the binocular vision measurement system to continuously photograph the frame plate and the surrounding aircraft body, import them into the whole aircraft coordinate system, and obtain the real-time position relationship of the frame plate in the whole aircraft coordinate system; Step 3.3: Continue to fine-tune the position of the frame, and use the binocular vision measurement system to monitor the position of the frame, and finally achieve precise installation positioning.

7. The method for repairing a damaged aircraft using high-precision visual measurement technology according to claim 1, characterized in that: The step 4 is specifically as follows: Step 4.1: After the damaged aircraft is repaired, post marking points and coding points inside and outside the air inlet; Step 4.2: Use a monocular vision measurement device to photograph the air inlet and integrate the obtained marked point cloud into the whole aircraft coordinate system; Step 4.3: Scan the marked points in the whole aircraft coordinate system, including the inner barrel and outer side of the left and right air inlet ducts, and obtain the point cloud images of the two air inlets; Step 4.4: Calculate and obtain a comparison diagram of the aerodynamic shapes of the repaired intake duct and the intact intake duct; Step 4.5: Obtain the aerodynamic shape concave-convex difference map through the aerodynamic shape comparison map to verify whether the repaired inlet duct aerodynamic shape is qualified; Step 4.6: Analyze multiple cross-sections of the air intake duct to determine whether the positional relationship of the air intake duct on the same horizontal plane of each section is qualified.

8. The method for repairing a damaged aircraft using high-precision visual measurement technology according to claim 7, characterized in that: In the step 4.4, if one of the two air inlets of the damaged aircraft is intact and the other is a repaired air inlet, the point cloud of the intact air inlet is mirrored with the aircraft center axis plane to obtain a comparison diagram of the aerodynamic shapes of the repaired air inlet and the intact air inlet.

9. The method for repairing a damaged aircraft using high-precision visual measurement technology according to claim 7, characterized in that: In the step 4.4, the two air inlets of the damaged aircraft are both repaired air inlets, and the point cloud image of the intact air inlets is imported to obtain a comparison image of the aerodynamic shapes of the two air inlets.

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