A method for off-line generation of robot trajectories for aircraft intrasew and extrasealant application

Abstract

The present application relates to a kind of robot trajectory offline generation method for aircraft inside seam, outside seam sealant coating.The method includes: inside seam glue coating trajectory generation method and outside seam glue coating trajectory generation method;Wherein, inside seam glue coating trajectory generation method is by determining the direction vector of edge point translation, the point on edge is translated into in-plane, and translation distance is half of glue coating width;Outside seam glue coating trajectory generation method is by the normal of two perpendicular planes of point on outside seam, then the included angle of two normal lines and axis are obtained, finally one of normal lines is rotated around the axis by half of included angle.Preliminary glue coating trajectory is generated by the above method, and the error compensation is carried out by guiding glue coating trajectory, and the final offline glue coating program is generated.Compared with prior art, the present application can automatically generate glue coating trajectory on digital model, more efficient, more widely applicable, and greatly reduce the time and labor cost of operation.

Description

Technical Field

[0001] This invention belongs to the technical field of aircraft skin sealant coating methods, and particularly relates to an offline robot trajectory generation method for coating sealants inside and outside aircraft seams. Background Technology

[0002] Applying adhesive to the skin is a crucial step in the production and processing of aircraft. Currently, it is generally completed through manual operation or robot teaching. Manual operation has problems such as low application accuracy, poor surface quality, large workload, and health hazards to workers. Robots combined with manual teaching have problems such as large workload and inability to adapt to frequently added product specifications, resulting in excessively high production costs, low work efficiency, and failure to meet user needs.

[0003] In addition, existing offline programming software usually does not support the automatic generation of glue application trajectory. It can only manually extract the features of the digital model and then manually generate the robot program, which consumes a lot of time and labor costs. Summary of the Invention

[0004] To overcome the aforementioned shortcomings of existing skin coating trajectory generation methods, this invention proposes a novel offline robot trajectory generation method for coating sealant inside and outside aircraft seams.

[0005] Terminology Explanation

[0006] Apply adhesive to the seam: Apply adhesive to the overlapping surface of the lower skin in the two skin layers; or apply adhesive to the contact surface between the honing and the skin.

[0007] Apply adhesive to the seam: Apply adhesive to the seam between the two sheets of skin that are glued together.

[0008] Trajectory point data: In addition to position information (x, y, z), trajectory point data also includes direction information, which can be represented by quaternions or by Euler angles (rotation angles about the z-axis, y-axis, and x-axis, respectively).

[0009] This method can automatically generate adhesive application trajectories on the digital model of the skin. Since there are discrepancies between the digital model and the actual skin, the adhesive application trajectory generated based on the digital model cannot be directly used in production. Therefore, this method uses a vision camera to identify corresponding edges and surfaces on the skin based on the adhesive application trajectory generated from the digital model, performs error compensation, and generates the final offline adhesive application trajectory. The overall process of this method includes:

[0010] (1) Import the skin and tooling model into the offline programming software.

[0011] (2) Select the corresponding edge, surface and other features on the skin, set the relevant parameters, and generate the initial glue application trajectory.

[0012] (3) Export the glue application trajectory, use a robot carrying a vision camera to run along the glue application trajectory once, perform error compensation, and generate the final offline glue application program.

[0013] The core of this method lies in its intermediate step, which involves selecting the corresponding edges, faces, and other features on the skin, setting relevant parameters, and generating a preliminary adhesive application trajectory.

[0014] Specifically, this invention provides an offline robot trajectory generation method for applying sealant inside and outside aircraft seams. This method includes: a method for generating an in-seam sealant application trajectory and a method for generating an out-of-seam sealant application trajectory; wherein:

[0015] The method for generating the adhesive application trajectory within the seam determines the direction vector of the edge point translation, and translates the points on the edge into the surface. The translation distance is half the adhesive application width.

[0016] The method for generating the adhesive trajectory outside the seam involves creating two normal lines on the vertical plane from points on the outer seam, obtaining the included angle and axis of the two normal lines, and finally rotating one of the normal lines around the axis by half the included angle.

[0017] Furthermore, the method for offline generation of robot trajectories for coating sealant inside and outside aircraft seams in this invention includes applying adhesive to the contact surface between the honing plate and the skin, as well as applying adhesive to the overlap of the two skins.

[0018] Furthermore, in the offline generation method of robot trajectory for coating sealant inside and outside aircraft seams, the present invention uses a blade-shaped applicator for applying adhesive inside the seam. The axis of the blade-shaped applicator is perpendicular to the plane of the long honing plate, and the blade direction of the blade-shaped applicator is perpendicular to the upper edge of the long honing plate.

[0019] Furthermore, the method for generating the adhesive application trajectory inside the seam in the offline robot trajectory generation method for coating sealant inside and outside aircraft seams according to the present invention includes:

[0020] S11. Select the upper edge of the honing piece on the digital model, and at the same time select the surface of the honing piece to be coated with glue;

[0021] S12. If the upper edge of the long hoop contains multiple line segments, sort them, and then generate discrete points according to the preset trajectory point spacing, and put them into the temporary point array pts;

[0022] S13. Loop through the pts array and take a point pt1. Draw the tangent line to the upper edge of the honing at this point, and then draw the normal line to the surface of the honing at this point. Cross-multiply the tangent line and the normal line to get the direction vector. Move pt1 along the direction vector by half the width of the adhesive to get another point pt2. Since the direction of the tangent line and the normal line is uncertain, it cannot be determined whether pt2 is on the surface of the honing. At this time, it is necessary to calculate the distance from pt2 to the surface of the honing. If it is greater than or equal to half the width of the adhesive, reverse the direction vector and then move pt1 along the direction vector by half the width of the adhesive to get pt2.

[0023] S14. Create the normal of the honing surface using pt2 as the direction data of pt2. Calculate the angle α between the horizontal direction of pt2 and the tangent of the honing edge based on this normal and vDir. Rotate pt2 around the normal by α degrees so that its horizontal direction is parallel to the tangent of the honing edge. Add pt2 to the adhesive application trajectory point array trac. If there are still points in the pts array, skip to step S13; otherwise, proceed to the next step.

[0024] S15. Return to the adhesive application trajectory inside the seam;

[0025] Where: vDir is the horizontal direction vector of the robot's initial state; pts is the array of temporary points; and trac is the array of glue application trajectory points.

[0026] Furthermore, in step S12 of the offline generation method for robot trajectory of sealant coating inside and outside aircraft seams, the preset trajectory point spacing is 20mm and the adhesive coating width is 16mm.

[0027] Furthermore, in the offline robot trajectory generation method for coating sealant inside and outside aircraft seams, the outer seam adhesive application refers to applying adhesive to the contact seam between the upper and lower skins after two skins are overlapped.

[0028] Furthermore, in the offline generation method of robot trajectory for coating sealant inside and outside aircraft seams, the present invention uses a needle-type applicator for applying adhesive outside the seam, and the angle between the needle-type applicator and two mutually perpendicular planes is 45 degrees.

[0029] Furthermore, the method for generating the external sealant coating trajectory in the offline robot trajectory generation method for coating sealant inside and outside aircraft seams according to the present invention includes:

[0030] S21. Select the outer seam segments of two skins on the digital model, and at the same time select two adjacent mutually perpendicular faces of the seam segments;

[0031] S22. If two skins contain multiple outer seam segments, sort them, then generate discrete points according to the preset trajectory point spacing, and put them into a temporary point array pts;

[0032] S23. Determine the normal directions of the two faces, retrieve the second point pt2 from the pts array, draw the normals of the two faces passing through this point, determine whether the normal directions need to be reversed, and save the two normals to normal1 and normal2.

[0033] S24. Loop through the pts array and take a point pt1. Draw the normals n1 and n2 of the two faces respectively. Compare the angle between them with the previously mentioned normal1 and normal2. First, calculate the angle between n1 and normal1. If the angle is close to 90 degrees, it means that n1 and normal1 are not normals of the same face. Then calculate the angle between n1 and normal2. If the angle is close to 180 degrees, n1 needs to be reversed. Process normal n2 in the same way. Update normal1 and normal2 with n1 and n2.

[0034] S25. Calculate the angle between n1 and n2, cross product n1 and n2 to get the axis vector, rotate n1 around the axis vector by angle / 2 degrees, and use it as the direction data of pt1. Add pt1 to the glue application trajectory point array trac; if there are still points in the pts array, skip to step S24, otherwise proceed to the next step.

[0035] S26. Return to the seam adhesive application trajectory;

[0036] Where: pts is a temporary point array; trac is an array of glue application trajectory points; normal1 and normal2 are the normal vectors of the two vertical planes, respectively.

[0037] Furthermore, in step S22 of the offline generation method for robot trajectories of sealant coating inside and outside aircraft seams, the preset trajectory point spacing is 20mm.

[0038] In addition, the present invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the above-described method for offline generation of robot trajectories for coating sealant inside and outside aircraft seams.

[0039] In summary, compared with existing methods for generating adhesive coating trajectories for aircraft skin, the present invention provides an offline robot trajectory generation method for coating sealant inside and outside aircraft seams. This method can automatically generate adhesive coating trajectories on digital models, resulting in higher efficiency, wider applicability, and significantly reduced operation time and labor costs. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the following drawings are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the adhesive application between the honed steel core and the skin in an embodiment of the present invention.

[0042] Figure 2 This is a schematic diagram of the adhesive application at the overlap of two skin sheets in an embodiment of the present invention.

[0043] Figure 3 This is a schematic diagram showing the working position of the blade-shaped adhesive nozzle when applying adhesive inside the seam in an embodiment of the present invention.

[0044] Figure 4 This is a schematic diagram of the adhesive application at the overlap of two skin sheets in an embodiment of the present invention.

[0045] Figure 5 This is a schematic diagram showing the working position of the needle-type glue applicator when applying glue to the outside of the seam in an embodiment of the present invention.

[0046] Figure 6 This is a schematic diagram illustrating the process of determining the normal directions of the two surfaces when applying adhesive to the seam in an embodiment of the present invention.

[0047] Figure 7 This is a schematic diagram illustrating the implementation process of the method for generating the adhesive coating trajectory within the seam in this invention.

[0048] Figure 8 This is a schematic diagram illustrating the implementation process of the method for generating the adhesive trajectory for the outer seam in the present invention. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. This invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this invention.

[0050] At the same time, it should be understood that the scope of protection of the present invention is not limited to the specific embodiments described below; it should also be understood that the terminology used in the embodiments of the present invention is for describing specific embodiments and not for limiting the scope of protection of the present invention.

[0051] Example: An offline method for generating robot trajectories for applying sealant inside and outside aircraft seams.

[0052] Adhesive application is divided into internal seam adhesive application and external seam adhesive application. Internal seam adhesive application includes applying adhesive to the contact surface between the honed steel and the skin, such as... Figure 1 The highlighted areas shown; and the glue applied at the overlap of the two skin sheets, as shown. Figure 2 As shown in the image, the highlighted skin is the lower skin, and the contact surface between it and the upper skin needs to be coated with adhesive.

[0053] Applying adhesive inside seams requires a blade-shaped applicator, such as... Figure 3 As shown, in addition to the axis of the nozzle being perpendicular to the plane of the long honing plate, the blade direction of the blade-shaped nozzle must also be perpendicular to the upper edge of the long honing plate. Figure 3 The highlighted line segment in the image, or in other words, the horizontal direction of the blade is parallel to the upper edge of the honing rod (this method operates according to this orientation), is necessary to ensure the quality of the adhesive application.

[0054] External adhesive application refers to applying adhesive to the seam where the upper and lower skins meet after two skins have overlapped. Figure 4 The highlighted lines are shown in the image. Applying adhesive to the seams requires a needle-type applicator, such as... Figure 5 As shown in the figure, the two highlighted surfaces are perpendicular to each other, and the angle between the needle nozzle and these two surfaces is 45 degrees.

[0055] Regarding the adhesive application trajectory within the seam, the main idea of ​​this invention is to translate the points on the edge into the surface. The translation distance is half the width of the adhesive application. The key point of this method is how to determine the direction vector of the translation. The following uses adhesive application on a long honed surface as an example to introduce the method for generating the adhesive application trajectory within the seam.

[0056] Methods for generating adhesive application trajectory within seams, such as Figure 7 As shown:

[0057] Definitions: The horizontal direction vector vDir of the robot end effector in its initial state, assuming a required glue application width of 16mm (which is also the width of the blade-shaped glue application nozzle); the trajectory point spacing is set to 20mm; the array of temporary points pts; and the array of glue application trajectory points trac.

[0058] 1. On the digital model, select the upper edge of the honing piece, and at the same time select the surface of the honing piece to be coated with glue.

[0059] 2. If the upper edge of the long purlin contains multiple line segments, sort them, then generate discrete points with a spacing of 20mm, and put them into a temporary array pts.

[0060] 3. Loop through points PTS and extract a point pt1. Draw the tangent line tangent to the upper edge of the sprue passing through this point, and then draw the normal line normal to the surface of the sprue passing through this point. Cross-multiply the tangent and normal to obtain the direction vector direction. Move pt1 along the direction by 8mm to obtain another point pt2. Because of the uncertainty of the directions of tangent and normal, it is not yet certain whether pt2 is on the surface of the sprue. Therefore, it is necessary to calculate the distance from pt2 to the surface of the sprue. If it is greater than or equal to 8mm, it means that the direction is reversed. Reverse the direction and move pt1 along the direction by 8mm to obtain pt2.

[0061] 4. Using the normal of the honing surface obtained through pt2 as the direction data of pt2, calculate the angle α between the horizontal direction of pt2 and the tangent of the honing edge tangent tangent based on the normal and vDir. Rotate pt2 around the normal by α degrees so that its horizontal direction is parallel to the tangent of the honing edge tangent. Add pt2 to the adhesive application trajectory point array trac. If there are still points in pts, skip to step 3; otherwise, proceed to the next step.

[0062] 5. Return to the adhesive application trajectory (trac) within the seam.

[0063] For applying adhesive to the outside of the seam, the main idea of ​​this method is to draw normals to two surfaces through points on the outside seam, then obtain the included angle and axis of the two normals, and rotate one of the normals around the axis by half the included angle. The specific method is as follows.

[0064] Methods for generating the adhesive trajectory for seam application, such as Figure 8 As shown:

[0065] Definitions: Set the trajectory point spacing to 20mm; temporary point array pts; normal vectors normal1 and normal2 of the two faces; adhesive application trajectory point array trac.

[0066] 1. On the digital model, select the outer seam segments of two skins, and at the same time select two adjacent mutually perpendicular faces of the seam segments.

[0067] 2. If it contains multiple line segments, sort them, then generate discrete points with a spacing of 20mm and put them into a temporary array pts.

[0068] 3. Determine the normal directions of the two faces. Extract the second point pt2 from pts (usually the first point is on the edge, so its normal direction is not representative). Draw the normals of the two faces passing through this point. You need to manually determine whether the normal directions need to be reversed, such as... Figure 6As shown, the two blue arrow lines are the normals of the two faces. Considering that the ends point to the intersection of the two faces, these two normals need to be reversed and saved to normal1 and normal2.

[0069] 4. Loop through points pts and extract a point pt1. Create normals n1 and n2 for two faces. Compare the angles between n1 and normal2 with the angles from normal1 and normal2. First, calculate the angle between n1 and normal1. If the angle is close to 90 degrees, n1 and normal1 are not normals of the same face. Then calculate the angle between n1 and normal2. If the angle is close to 180 degrees, n1 needs to be reversed. Repeat the same process for normal n2. Update normal1 and normal2 with n1 and n2.

[0070] 5. Calculate the angle between n1 and n2, cross product n1 and n2 to get the axis vector axis, rotate n1 around axis by angle / 2 degrees, use it as the direction data of pt1, and add pt1 to the glue application trajectory array trac; if there are still points in pts, skip to step 4, otherwise proceed to the next step.

[0071] 6. Return to the trac track for applying adhesive to the seam.

[0072] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to obtain equivalent embodiments without departing from the scope of the technical solution of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the technical solution of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for offline generation of robot trajectories for applying sealant to the inside and outside of aircraft seams, characterized in that, The method includes: a method for generating an in-seam adhesive application trajectory and a method for generating an out-seam adhesive application trajectory; wherein: The adhesive coating inside the seam includes applying adhesive to the contact surface between the honing and the skin, and applying adhesive to the overlap of the two skins. The method for generating the adhesive application trajectory within the seam determines the direction vector of the edge point translation, translating the points on the edge into the surface by a translation distance equal to half the adhesive application width; including: S11. Select the upper edge of the honing piece on the digital model, and at the same time select the surface of the honing piece to be coated with glue; S12. If the upper edge of the long pendulum contains multiple line segments, sort them, and then generate discrete points according to the preset trajectory point spacing, and put them into the temporary point array pts; S13. Loop through the pts array and take a point pt1. Draw the tangent line to the upper edge of the honing at this point, and then draw the normal line to the surface of the honing at this point. Cross-multiply the tangent line and the normal line to get the direction vector. Move pt1 along the direction vector by half the width of the adhesive to get another point pt2. Since the direction of the tangent line and the normal line is uncertain, it cannot be determined whether pt2 is on the surface of the honing. At this time, it is necessary to calculate the distance from pt2 to the surface of the honing. If it is greater than or equal to half the width of the adhesive, reverse the direction vector and then move pt1 along the direction vector by half the width of the adhesive to get pt2. S14. Create the normal of the honing surface through pt2 as the direction data of pt2. Calculate the angle α between the horizontal direction of pt2 and the tangent of the honing edge based on this normal and vDir. Rotate pt2 around the normal by α degrees so that its horizontal direction is parallel to the tangent of the honing edge. Add pt2 to the adhesive application trajectory point array trac. If there are still points in the pts array, skip to step S13; otherwise, proceed to the next step. S15. Return to the adhesive application trajectory inside the seam; Where: vDir is the horizontal direction vector of the robot's initial state; pts is the array of temporary points; and trac is the array of glue application trajectory points. The term "seam adhesive application" refers to applying adhesive to the seam where the upper and lower skins meet after the two skins are overlapped. The method for generating the adhesive trajectory outside the seam involves creating normals to two perpendicular planes from points on the outer seam, obtaining the included angle and axis of the two normals, and finally rotating one of the normals around the axis by half the included angle; including: S21. Select the outer seam segments of two skins on the digital model, and at the same time select two adjacent mutually perpendicular faces of the seam segments; S22. If two skins contain multiple outer seam segments, sort them, then generate discrete points according to the preset trajectory point spacing, and put them into a temporary point array pts; S23. Determine the normal directions of the two faces, retrieve the second point pt2 from the pts array, draw the normals of the two faces passing through this point, determine whether the normal directions need to be reversed, and save the two normals to normal1 and normal2. S24. Loop through the pts array and take a point pt1. Draw the normals n1 and n2 of the two faces respectively. Compare the angle between n1 and normal2 with the angle between normal1 and normal2. First, calculate the angle between n1 and normal1. If the angle is close to 90 degrees, it means that n1 and normal1 are not normals of the same face. Then calculate the angle between n1 and normal2. If the angle is close to 180 degrees, n1 needs to be reversed. Process normal n2 in the same way. Update normal1 and normal2 with n1 and n2. S25. Calculate the angle between n1 and n2, cross product n1 and n2 to obtain the axis vector, rotate n1 around the axis vector by angle / 2 degrees, use it as the direction data of pt1, and add pt1 to the adhesive trajectory point array trac; if there are still points in the pts array, skip to step S24, otherwise proceed to the next step; S26. Return to the seam adhesive application trajectory; Where: pts is a temporary point array; trac is an array of glue application trajectory points; normal1 and normal2 are the normal vectors of the two vertical planes, respectively.

2. The offline robot trajectory generation method for applying sealant inside and outside aircraft seams according to claim 1, characterized in that, The adhesive is applied to the seam using a knife-shaped applicator. The axis of the knife-shaped applicator is perpendicular to the plane of the long honing plate, and the blade direction of the knife-shaped applicator is perpendicular to the upper edge of the long honing plate.

3. The offline robot trajectory generation method for applying sealant inside and outside aircraft seams according to claim 1, characterized in that, The preset trajectory point spacing in step S12 is 20mm; the adhesive application width is 16mm.

4. The method for offline generation of robot trajectories for applying sealant inside and outside aircraft seams according to claim 1, characterized in that, The adhesive coating on the seam uses a needle-type applicator, with the needle-type applicator forming a 45-degree angle with both of the two mutually perpendicular planes.

5. The method for offline generation of robot trajectories for applying sealant inside and outside aircraft seams according to claim 1, characterized in that, The preset trajectory point spacing mentioned in step S22 is 20mm.

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