Positioning Method for Injection Hole of Groove Seal of Aircraft Fuel Tank

Abstract

The present invention provides a positioning method for the injection holes of the groove seal of an aircraft fuel tank, belonging to the field of aviation manufacturing engineering / aircraft assembly. The steps include: marking the projection point of the center point of the injection hole on the bottom surface of the groove, taking two auxiliary points on the bottom surface of the groove with the projection point as the center to establish a detection coordinate system, creating an analysis program for the positioning deviation of the injection hole and setting parameters. After installing the panel, using a probe to detect the position deviation between the measured point and the projection point on the panel. When the position deviation is within the range of ±5 mm, pasting a detection auxiliary mark, further detecting the measured point within the range of the detection auxiliary mark until its position deviation from the projection point meets the set parameter range, marking this point on the detection auxiliary mark and drilling a blind hole, and completing the drilling of the injection hole after tearing off the detection auxiliary mark. The present invention solves the problem of difficult positioning of the injection hole, makes the entire operation process have controllable precision and high efficiency, avoids human errors, and improves the assembly quality of the product.

Description

Technical Field

[0001] The present invention belongs to the field of aviation manufacturing engineering / aircraft assembly, and relates to a positioning method for injection holes of the groove seal of an aircraft fuel tank, which makes the entire operation process have controllable precision and high efficiency, avoids human errors, and improves the assembly quality of products. Background Art

[0002] Groove seal is a method for sealing an aircraft fuel tank, which has the advantages of easy maintenance, light weight of the sealing material, and stable and reliable sealing effect. Groove seal requires a groove 2 to be provided on the sealing surface of the aircraft skeleton 1. As shown in Figure 1 After the panel 3 is installed, a sealing material injection hole 4 is drilled on the panel 3, as shown in Figure 2 After the panel 3 is installed, a sealing material injection hole 4 is drilled on the panel 3, as shown in Summary of the Invention

[0003] In view of the above problems existing in the prior art, the present invention provides a positioning method for injection holes of the groove seal of an aircraft fuel tank, which includes a positioning process for injection holes of the groove seal based on digital measurement, a design of a detection coordinate system, a design of measurement and analysis parameters, and a design of detection auxiliary marks.

[0004] The technical solution adopted by the present invention is as follows:

[0005] A positioning method for injection holes of the groove seal of an aircraft fuel tank combines digital measurement, a custom coordinate system, and the creation of equivalent points. The entire process includes eleven steps, as shown in Figure 3 The positioning method includes the following steps:

[0006] Step 1: Set the center point of the theoretical injection hole of the wall panel as T. First, use the method of scribing to mark the projection point of the injection hole center T on the bottom surface 6 of the groove, denoted as A. The projection direction is perpendicular to the surface of the wall panel 3 and also perpendicular to the bottom surface 6 of the groove, as Figure 4 shown.

[0007] Step 2: Taking point A as the center, take two points B and C on the bottom surface 6 of the groove within the range of a radius from 5 mm to 8 mm as auxiliary points. It is required that the connection direction between A and B is parallel to the axis direction of the groove 2, and A, B, and C cannot be collinear, as Figure 5 shown.

[0008] Step 3: Use the probe 7 of the contact-type digital measuring instrument to measure the spatial coordinates of these three points, and record the coordinate values of the three points. Among them, the diameter of the probe tip is not greater than 0.2 mm. As Figure 6 shown.

[0009] Step 4: Create a detection coordinate system based on the coordinate values of A, B, and C, and convert the world coordinate system of the measuring instrument into the detection coordinate system, as shown in Figure 7(a) and Figure 7(b). The purpose of coordinate system conversion is to eliminate the angular deviation and origin deviation between coordinate systems, so that the subsequent steps can be implemented quickly and accurately.

[0010] Step 5: Create an injection hole position positioning deviation analysis program in the digital measuring analysis software, and set the parameters of the analysis program for deviation judgment and deviation correction guidance during the hole position determination process, where point T is set as the detection target point.

[0011] Step 6: Install the wall panel 3.

[0012] Step 7: Run the injection hole position positioning deviation analysis program created in Step 5. Use the probe 7 of the contact-type digital measuring instrument to find the target point T on the wall panel 3. Each detection will display the deviation between the coordinates of the actual probe contact point (i.e., the measured point) and the target point T. The deviation includes the X-direction deviation, Y-direction deviation, and Z-direction deviation. Since the Z-direction error has no influence on the overall deviation, the deviation actually includes the X-direction deviation and Y-direction deviation, as Figure 8 、 9 shown.

[0013] Step 8: When the X-direction deviation and Y-direction deviation are within the range of ±5 mm, mark the position where the probe 7 stays on the wall panel 3 and paste the detection auxiliary mark 10, as Figure 9 shown.

[0014] Step 9: Use the probe 7 of the contact-type digital measuring instrument to detect on the detection auxiliary mark 10, and continue to check the X and Y direction deviations between the measured point and the target point T, as Figure 10As shown. When the deviation value is not greater than the qualified range of the parameters set in the injection hole position positioning deviation analysis program in the fifth step, the probe 7 stays at this position, and a small hole is drilled on the detection auxiliary mark 10, and the position of this hole is the position of the injection hole 4.

[0015] Step 10: Use a pneumatic drill to drill a blind hole with a depth of 1 mm at the position of the hole on the detection auxiliary mark 10 as the hole-making position mark of the injection hole 4, and tear off the detection auxiliary mark 10.

[0016] Step 11: Complete the drilling of the injection hole 4 according to the hole-making requirements.

[0017] Further, in the fourth step, the reason for creating the detection coordinate system: When the measuring instrument collects data, it defaults to the world coordinate system, and the origin of the world coordinate system is on the device. The installation position of the measuring instrument is random. Therefore, the directions of the axes of the world coordinate system are not parallel / perpendicular to the groove bottom surface 6, which will cause an angle between the vector direction of the projection point A on the groove bottom surface 6 and a certain axis of the world coordinate system. After the projection point A is projected onto the outer surface of the wall plate 3 along the vector direction, the X, Y, and Z values in the coordinates of the injection hole center point T will all change, and this change is unpredictable, resulting in the inability to perform subsequent detection. Therefore, it is necessary to create a detection coordinate system to convert the world coordinate system of the measuring instrument to a custom detection coordinate system. After the point A is projected onto the outer surface of the wall plate 3, the coordinate offsets of the projection point (i.e., the center T of the injection hole) in the X and Y directions are eliminated, and at the same time, the Z-direction deviation is made invalid. In this way, the coordinates of the measured points can intuitively reflect the deviation from the target point T, enabling the smooth implementation of the present invention, as Figure 6 shown in and 7.

[0018] The method for creating the detection coordinate system includes the following steps:

[0019] 1) Define the detection coordinate system: Create a Cartesian coordinate system using three point elements A, B, and C. Among them, point A is the origin of the coordinate system, the line formed by A and B is the Y-axis, and the vector direction of the plane formed by points A, B, and C is the Z-axis; the connection line AB is parallel to the extension axis of the groove 2, so the Y-axis is parallel to the extension axis of the groove 2, and the Z-axis is parallel to the vector direction of A. Based on the above definition, the X direction is automatically perpendicular to the groove side wall 5, and the X-axis coordinate represents the distance of the measurement point relative to the axis plane of the groove 2. Then the coordinates of A are (0, 0, 0), and the coordinates of point T are (0, 0, 0 + △), where △ is the length of the line segment AT.

[0020] 2) Optimize the detection coordinate system error: The purpose of optimization is to analyze the overall error of the measuring instrument. Combining with the position accuracy requirement of the injection hole 4 given in the design, a qualified interval of the measurement value during detection is given to ensure the position accuracy of the injection hole 4 even in the presence of measuring instrument error. The better the detection coordinate system error is optimized, the larger the tolerance value during detection, and the higher the reliability of the present invention. The error of the detection coordinate system is divided into the X-direction error △X, the Y-direction error △Y, and the Z-direction error △Z. The overall error S is the square root of the sum of the squares of the three, that is, S = sqrt(△X 2 +△Y 2 +△Z 2 ). Thanks to the definition method of our detection coordinate system, the Z-direction error has no influence on the overall error S. Therefore, the overall error is artificially reduced. At the same time, the maximum allowable deviation in the Y direction is 3 mm, which is much larger than the error of general digital measuring instruments and can be ignored. Finally, the overall error is only in the X direction, in the state with the least influence on the measurement result, that is, S = △X.

[0021] Further, in the fifth step, setting the parameters in the positioning deviation analysis program means setting the measurement evaluation strategy of the positioning deviation analysis program, including setting the final tolerance, the rough measurement tolerance, the display items of the measurement information, and the semantic expression of the color of the compilation items. The specific steps are as follows:

[0022] 1) Set the final tolerance: The final tolerance of the injection hole 4, that is, the deviation requirement of the measured point is the Y-direction deviation of ±2 mm and the X-direction deviation of ±1 mm relative to the target point T. Since the X and Y coordinates of the T point are both 0, the coordinate value of the measured point is the deviation of the measured point. Considering the instability of the measuring instrument and the deviation of the drilling, the final tolerance is set to the Y-direction deviation of ±1.5 mm and the X-direction deviation of ±0.5 mm, that is, the Y coordinate is within ±1.5 mm and the X-direction coordinate is within ±0.5 mm.

[0023] 2) Set the rough measurement tolerance: Add the rough measurement tolerance R on the basis of the final tolerance. R = ±5 mm, which is used to determine the pasting position of the detection auxiliary mark 10. The rough measurement tolerance characterizes the 3D distance between the measured point and the target point. The 3D distance is equal to the square root of the sum of the squares of the X-direction deviation and the Y-direction deviation.

[0024] 3) Set the display items of the measurement information: The display items are set to include three parts, the X coordinate, the Y coordinate, and the rough measurement tolerance of the measured point, which are used to reflect the deviation between the current measured point and the target point T to guide the adjustment of the detection position.

[0025] 4) Semantic expression of the color of the entry: Since the display for showing the entry is at a relatively long distance, the specific numerical value of the information is not clear, which affects the detection efficiency. Therefore, the color of the displayed entry is regulated. Color is easier to be recognized by the human eye than the specific numerical value. The semantic expression of the color is as follows: When the X coordinate is within the range of ±0.5 mm, the color is green; when the Y coordinate is within the range of ±1.5 mm, the color is green; when the X coordinate is greater than 0.5 mm, the color is red; when the X coordinate is less than -0.5 mm, the color is blue. When the Y coordinate is greater than 1.5 mm, the color is red; when the Y coordinate is less than -1.5 mm, the color is blue. When the 3D distance is less than or equal to 5 mm, the entry is displayed in yellow, and when it is greater than 5 mm, it is purple. By checking the color of the roughly measured tolerance, the initial positioning of the target point is completed first, and the target point is locked within the range of a diameter of 10 mm; then check the X and Y coordinates, and adjust the moving direction of the probe 7 through the display of the color, which can effectively improve the efficiency.

[0026] Further, in the eighth step, the detection auxiliary mark 10 is used to improve the detection efficiency and at the same time serve as a carrier for marking the position of the injection hole 4, as Figure 9 shown. The detection auxiliary mark 10 includes a self-adhesive sticker 8 with a thickness of 0.5 mm and a diameter of 10 mm and a plane rectangular coordinate system 9 printed on the self-adhesive sticker 8; the sticker is a consumable. The thickness of 0.5 mm is to make a mark on the detection auxiliary mark 10 after pressing down the probe 7 after the probe 7 finds the correct position. If the thickness of the mark is too small, the mark is not obvious, and conversely, it will cause deviation of the marked position; a plane rectangular coordinate system 9 is printed on the detection auxiliary mark 10, including an X coordinate axis and a Y coordinate axis, respectively passing through the center of the detection auxiliary mark 10, the length of the coordinate axis is equal to the diameter of the detection auxiliary mark 10, and the scale spacing of the coordinate axis is 0.1 mm. After the measured point enters the roughly measured range, stick the detection auxiliary mark 10 at the position where the probe is located, determine that the position of the target point is within the range of the detection auxiliary mark 10, and the position deviation of the probe 7 can be determined by observing the color or numerical value of the displayed entry on the display. The X axis and Y axis on the plane rectangular coordinate system 9 are used to remind the correct moving direction and moving amount, and it is necessary to ensure that the Y direction on the detection auxiliary mark 10 is parallel to the extension direction of the groove, and the edge of the wall panel 3 can be referred to, because the edge of the wall panel 3 is parallel to the extension direction of the groove 2 to improve the detection efficiency.

[0027] Advantages of the present invention: The present invention solves the problem of difficult positioning of the injection hole during the groove sealing process of the aircraft fuel tank. By comprehensively applying methods such as the marking method, digital measurement, color marking, and physical marking, the entire operation process is controllable in precision and efficient, avoiding human errors and improving the assembly quality of the product. Description of the Drawings

[0028] Figure 1Schematic diagram of the groove structure of the aircraft frame. Among them, (a) is the overall schematic diagram of the aircraft frame, and (b) is the sectional view.

[0029] Figure 2 Schematic diagram of the groove sealing injection hole on the panel. Among them, (a) is the overall schematic diagram, and (b) is the sectional view.

[0030] Figure 3 Flowchart of the positioning method for the groove sealing injection hole of the aircraft fuel tank.

[0031] Figure 4 Schematic diagram of the center point T of the groove sealing injection hole of the aircraft fuel tank and the projection point A of the groove bottom surface.

[0032] Figure 5 Schematic diagram of the auxiliary points for establishing the detection coordinate system. In the figure, B and C represent the auxiliary points, and E represents the groove axis.

[0033] Figure 6 Schematic diagram of the punctuation points on the groove bottom surface for detection.

[0034] Figure 7(a) and Figure 7(b) are schematic diagrams for establishing the detection coordinate system.

[0035] Figure 8 Schematic diagram of detecting the target point on the panel.

[0036] Figure 9 Schematic diagram of the detection auxiliary mark.

[0037] Figure 10 Schematic diagram of detecting the target point on the detection auxiliary mark.

[0038] In the figure: 1 aircraft frame; 2 groove; 3 panel; 4 injection hole; 5 groove side wall; 6 groove bottom surface; 7 probe; 8 self-adhesive sticker; 9 plane rectangular coordinate system; 10 detection auxiliary mark. Detailed implementation manners

[0039] Next, the technical solution of the present invention will be described clearly and completely. The examples of the embodiments are shown in the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments improved or adjusted by those of ordinary skill in the art belong to the protection scope of the present invention.

[0040] A positioning method for the groove sealing injection hole of an aircraft fuel tank, the process is as Figure 3 shown, and the positioning method includes the following steps:

[0041] 1) Place the aircraft fuel tank assembly on the bracket and fix it, with the height between 800 mm and 1200 mm.

[0042] 2) Set up the digital measuring instrument to ensure that the measuring field of the instrument can cover the position to be detected.

[0043] 3) Remove the wall panel 3 and place it on another bracket.

[0044] 4) Refer to the position of the injection hole T in the digital mock-up, and draw a point A at the corresponding position on the bottom surface 6 of the groove, that is, the projection point of point T on the bottom surface 6 of the groove. The projection direction is perpendicular to the outer surface of the wall panel 3 and also perpendicular to the bottom surface 6 of the groove, as Figure 4 shown.

[0045] 5) Take two points B and C as auxiliary points within the range of 5 mm - 8 mm centered on the intersection point A. It is required that the connection direction between A and B is as parallel as possible to the axial direction of the groove 2, and the three points A, B, and C are not collinear, as Figure 5 shown.

[0046] 6) Turn on the digital measuring device, install a probe with a length of 50 mm and a tip diameter of 0.2 mm, and perform probe calibration to ensure that the calibration measurement accuracy is within the range of 0.05 mm.

[0047] 7) Use the probe 7 of the contact digital measuring instrument to measure the spatial coordinates of these 3 points, record the coordinate values of the 3 points, and generate 3 feature points in the measuring software, as Figure 6 shown.

[0048] 8) Click to create a coordinate system in the measuring software. Create a detection coordinate system according to the coordinate values of A, B, and C, and convert the world coordinate system of the instrument into the detection coordinate system. Adopt the point-line-plane mode, with point A as the origin, the connection line between A and B as the Y-axis, the X-axis perpendicular to the side wall of the groove, and the Z-axis perpendicular to the bottom surface of the groove, as shown in Figures 7(a) and 7(b).

[0049] 9) Create a detection project in the digital measuring and analysis software, that is, an injection hole position deviation analysis program, with point T as the detection target point, and set the detection project to X-direction deviation, Y-direction deviation, and 3D distance. Set the tolerances of the detection project, with a Y-direction tolerance of ±1.5 mm, an X-direction tolerance of ±0.5 mm, and a rough measurement tolerance of 5 mm.

[0050] 10) Set the display colors of the display items in the monitor during the detection process: when the X coordinate is within the range of ±0.5 mm, the color is green; when the Y coordinate is within the range of ±1.5 mm, the color is green; when the X coordinate is greater than 0.5 mm, the color is red; when the X coordinate is less than -0.5 mm, the color is blue. When the Y coordinate is greater than 1.5 mm, the color is red; when the Y coordinate is less than -1.5 mm, the color is blue. When the rough measurement tolerance is less than or equal to 5 mm, the item is displayed in yellow, and when it is greater than 5 mm, it is displayed in purple.

[0051] 11) Restore the installation of the wall panel 3.

[0052] 12) Run the injection hole position positioning deviation analysis program. Use the probe 7 of the contact digital measuring instrument to find the target point T on the wall panel 3, which is also point A because the X and Y coordinates of point A and point T are the same. As Figure 8 shown. Each detection will display the deviation between the coordinates of the actual probe contact point and the target point T on the display. The deviation includes the X-direction deviation, Y-direction deviation, and rough measurement tolerance.

[0053] 13) When the X-direction deviation and Y-direction deviation are within the range of ±5 mm, the rough measurement tolerance in the display entry will be displayed in yellow. At this time, mark the position where the probe stays on the wall panel, make a mark with a marking table, and paste the detection auxiliary identifier 10 with the mark as the center and the wall panel edge parallel to the Y-axis as the reference condition. As Figure 9 shown.

[0054] 14) Use the probe 7 of the contact digital measuring instrument to detect on the detection auxiliary identifier 10, and continue to check the X and Y direction deviations between the measured point and the target point T. As Figure 10 shown. When the X-direction and Y-direction deviations in the display entry are both displayed in green, stop the probe 7 at that position and slightly press to make a small hole on the detection auxiliary identifier 10. The position of this hole is the position of the injection hole 4.

[0055] 15) Use a pneumatic drill to drill a blind hole with a depth of about 1 mm at this hole position. This blind hole serves as the drilling position mark for the injection hole 4, and finally tear off the detection auxiliary identifier 10.

[0056] 16) Based on the blind hole mark left on the wall panel, use a pneumatic drill to drill the injection hole 4 to the final hole.

[0057] The description of this embodiment is only exemplary and not all embodiments. All other embodiments improved or adjusted by those of ordinary skill in the art belong to the protection scope of the present invention.

Claims

1. A positioning method for the injection hole of the groove seal of an aircraft fuel tank, characterized in that The positioning method includes the following steps: First step: Set the center point of the theoretical injection hole of the wall panel as T. First, mark the projection point of the injection hole center T on the bottom surface (6) of the groove, designated as A. The projection direction is perpendicular to the surface of the wall panel (3) and also perpendicular to the bottom surface (6) of the groove; Second step: With point A as the center, take two points B and C as auxiliary points within a radius range of 5 mm to 8 mm on the bottom surface (6) of the groove. It is required that the connection direction between A and B is parallel to the axis direction of the groove (2), and A, B, and C are not collinear; Third step: Use the probe (7) of the measuring instrument to measure the spatial coordinates of these three points and record the coordinate values of the three points; Fourth step: Create a detection coordinate system based on the coordinate values of A, B, and C, and convert the world coordinate system of the measuring instrument into the detection coordinate system; Fifth step: Create an injection hole position positioning deviation analysis program, set parameters for deviation judgment and deviation correction guidance during the hole position determination process, and set point T as the detection target point; Sixth step: Install the wall panel (3); Seventh step: Run the injection hole position positioning deviation analysis program created in the fifth step. Use the probe (7) to find the target point T on the wall panel (3), and display the deviation between the measured point coordinates and the target point T; The deviation includes the X-direction deviation, Y-direction deviation, and Z-direction deviation. Since the Z-direction error has no impact on the overall deviation, the deviation actually includes the X-direction deviation and Y-direction deviation; Eighth step: When the X-direction deviation and Y-direction deviation are within the range of ±5 mm, mark the position where the probe (7) stays on the wall panel (3) and paste the detection auxiliary mark (10); Ninth step: Use the probe (7) to detect on the detection auxiliary mark (10), and continue to check the X and Y direction deviations between the measured point and the target point T; When the deviation value is not greater than the parameter range set in the injection hole position positioning deviation analysis program in the fifth step, stop the probe (7) at this position and punch a small hole on the detection auxiliary mark (10). The position of this hole is the position of the injection hole (4); Tenth step: Drill a blind hole according to the position of the hole on the detection auxiliary mark (10) as the marking for the hole-making position of the injection hole (4), and tear off the detection auxiliary mark (10); Eleventh step: Drill the injection hole (4) according to the hole-making requirements; In the fourth step, the method for creating the detection coordinate system includes the following steps: Define the detection coordinate system: Create a Cartesian coordinate system using three point elements A, B, and C; where point A is the origin of the coordinate system, the straight line formed by A and B is the Y-axis, and the vector direction of the plane formed by points A, B, and C is the Z-axis; The connection line AB is parallel to the extension axis of the groove (2), so that the Y-axis is parallel to the extension axis of the groove (2), and the Z-axis is parallel to the vector direction of A. Based on the above definition, the X direction is automatically perpendicular to the side wall (5) of the groove; In the fifth step, set the parameters in the positioning deviation analysis program, including setting the final tolerance, rough measurement tolerance, display items of measurement information, and semantic expression of the color of the compilation items. Specifically, it includes the following steps: 1) Set the final tolerance: Since the X and Y coordinates of point T are both 0, the coordinate values of the measured points are the deviations of the measured points. Set the final tolerance to ±1.5 mm for the Y - direction deviation and ±0.5 mm for the X - direction deviation; 2) Set the rough - measurement tolerance: Add the rough - measurement tolerance R on the basis of the final tolerance, where R = ±5 mm, which is used to determine the pasting position of the detection auxiliary mark (10). The rough - measurement tolerance represents the 3D distance between the measured point and the target point. The 3D distance is equal to the square root of the sum of the square of the X - direction deviation and the square of the Y - direction deviation; 3) Set the display items of the measurement information: Include the X coordinate, Y coordinate of the measured point and the rough - measurement tolerance, which are used to guide the adjustment of the detection position; 4) Compile the semantic expression of the item color.

2. The positioning method of the injection hole for the groove seal of an aircraft fuel tank according to claim 1, characterized in that The semantic expression of the color is as follows: When the X coordinate is within the range of ±0.5 mm, the color is green; when the Y coordinate is within the range of ±1.5 mm, the color is green; when the X coordinate is greater than 0.5 mm, the color is red; when the X coordinate is less than - 0.5 mm, the color is blue; when the Y coordinate is greater than 1.5 mm, the color is red; when the Y coordinate is less than - 1.5 mm, the color is blue; when the 3D distance is less than or equal to 5 mm, the item is displayed in yellow, and when it is greater than 5 mm, it is purple.

3. A positioning method for the injection hole of the groove seal of an aircraft fuel tank according to claim 1, characterized in that, In the eighth step described above, the detection auxiliary mark (10) includes a self - adhesive sticker (8) and a plane rectangular coordinate system (9) printed on the self - adhesive sticker (8). The X - axis and Y - axis on the plane rectangular coordinate system (9) are used to remind the correct moving direction and moving amount.

4. A positioning method for the injection hole of the groove seal of an aircraft fuel tank according to claim 3, characterized in that The thickness of the detection auxiliary mark (10) is 0.5 mm and the diameter is 10 mm.

Images