Method for repairing sawtooth skin in butt joint of large parts and line drawing device

Abstract

The invention belongs to the technical field of aeronautical manufacturing, and discloses a repairing method and a line drawing device for a sawtooth skin in butt joint of large components, and the repairing method comprises the following steps: unifying repairing references for different components; performing motion simulation based on skin reconstruction; the sawtooth skin line drawing device is designed according to the parameters of the skin thickness, the repairing position and the included angle between the skin projection and the course, rapid and accurate line drawing is carried out in the final assembly stage according to a tool, and repairing is carried out according to the drawn line. According to the method, the problem that the sawtooth skin is difficult to repair in the final assembly stage due to skin partitioning, curvature change, assembly assembling errors and the like is solved, the limitation that only part manufacturing errors are reduced in an existing method is broken through, and part assembling errors and butt joint errors are reduced; the sawtooth skin repairing scheme can be applied to production practice of butt joint of aircraft parts.

Description

Technical Field

[0001] The invention belongs to the technical field of large aircraft component docking in aviation manufacturing, and specifically relates to a method for repairing serrated skins in large component docking and a line drawing device. Background Art

[0002] Some aircraft use the form of sawtooth skin frame-to-frame or frame-to-frame docking. Due to the accumulation of errors such as part manufacturing errors, component assembly errors, part drawing errors, and component attitude adjustment docking errors, the sawtooth skin is difficult to repair and cannot meet the design requirements of the skin joint gap. During the docking process, when there are many wall panels, many serrations, and large changes in curvature, there will be uneven gaps after the sawtooth skin is docked or local interference during the docking process. The proposal and application of a reasonable solution for the repair of sawtooth skins is of great significance for the docking of large components.

[0003] At present, some researchers have proposed using laser measurement to obtain point clouds, and using intelligent algorithms to perform point screening and surface reconstruction to solve the problem of sawtooth skin repair. However, the above research is to solve the problem of how to generate machining feed paths, and it is repaired from the part manufacturing level, without considering the most core component assembly errors and component docking errors in the docking of large components.

[0004] Therefore, there is a need for an integrated serrated skin repair solution from component assembly to component posture adjustment to component docking to solve the problem of repairing serrated skin without a reference in the docking of large components. Summary of the invention

[0005] The present invention application proposes a method for repairing serrated skins in large component jointing and a line drawing device to solve the problems in the above-mentioned background technology.

[0006] In order to achieve the above invention objectives, the technical solutions adopted in this application are as follows:

[0007] A method for repairing a sawtooth skin in large component jointing, comprising the following steps:

[0008] Unified repair standards for different parts: During the assembly stage, different component assembly jigs are set with consistent curvature and serrated pallet tooling that follows each other. The skins of different components are repaired based on this tooling, and the components are delivered with margins after repair;

[0009] Motion simulation based on skin reconstruction: Scan the skin contour with laser measuring equipment, import the measured points into CATIA, reconstruct the skin contour based on the imported points through secondary development technology, perform motion simulation after reconstruction, and find local interference points on the path;

[0010] The sawtooth skin drawing device is designed according to the parameters of skin thickness, trimming position, skin projection and heading angle. The line drawing is carried out quickly and accurately in the final assembly stage according to the tooling, and the trimming is carried out based on the drawn lines.

[0011] As a further solution of the present invention: the unified repairing benchmark for different components specifically includes the following steps:

[0012] According to the digital model of the net edge skin of the reference component, the manufacturing size of the net edge serrated skin is the deviation from the design requirement, the skin is fixed on the component assembly jig and a serrated clamping plate following the theoretical model of the net edge skin is set;

[0013] The remaining skin of another component is fixed on the assembly jig of another component and fits with the remaining edge serrated pallet, and the remaining edge serrated pallet has the same shape and curvature as the net edge skin serrated pallet;

[0014] The theoretical model shapes and curvature changes of the serrated pallets of the two components are consistent with each other, and the serrated skins of different components are repaired along the pallets to form a unified benchmark; after the skin with allowance is repaired, three-quarters of the allowance is left, and the repair will continue when the components are docked.

[0015] As a further solution of the present invention: the motion simulation specifically comprises the following steps:

[0016] In the component posture adjustment stage, after the component is put on the shelf, the skin contour measurement system is used to scan the skin contour of the net edge and the residual edge sawtooth. The measurement system consists of TSCAN, a laser tracker, and corresponding control software. TSCAN is used to scan the skin sawtooth obliquely above the skin to obtain a point cloud model containing several scan lines.

[0017] Traverse the point set on the scan line, use KD-TREE to narrow the search area, set a point position threshold, and divide each point and its adjacent threshold number of points into a region; extract the boundary points of the sawtooth skin based on the discrete curvature analysis results of the points, set an angle threshold, and use a point P0 in a divided area as a reference to screen out the points P1 and P2 adjacent to it on both sides, calculate the angles of P0 P1 and P0 P2, and compare them with the threshold to determine the sawtooth boundary points;

[0018] The Y-component coordinate values ​​of the points in the aircraft coordinate system are recursively sorted and connected in sequence; the boundary lines of the residual skin and the net edge reconstruction are projected onto the horizontal plane of the aircraft digital model, and the uniformity of the gap of the serrated skin after docking in the current attitude can be obtained; the aircraft attitude is adjusted according to the results.

[0019] As a further solution of the present invention: the line drawing and repairing specifically comprises the following steps:

[0020] Usually the sawtooth skin is in the form of frame docking or plate overlap. When the gap of the sawtooth skin is uniform, the CNC positioner is withdrawn Xmm in the reverse direction, and the sawtooth skin is marked with a T-type support block tooling and a convex and concave rounded support block tooling; the marking pen is inserted into the support block placement hole to mark the product, and the side wall is provided with a limit bolt to adjust the position of the marking pen.

[0021] The size of the convex and concave fillet support block tooling is determined by two parameters (R, h), where R is the radius of the sawtooth convex and concave fillets, and h is the length of the straight edges on both sides of the fillet of the support block; the straight edges are fitted to the above-mentioned drawn lines, and the lines are drawn along the fillet edges.

[0022] As a further solution of the present invention: the size of the T-type support block tooling is determined by four parameters (α, d, b, w); α is the angle between the serrated edge and the heading after the serrated skin is projected onto the horizontal plane of the aircraft structure, d is the distance that the CNC positioner withdraws along the heading when drawing a line, b is the wall panel thickness input, and w is the support block width input.

[0023] A sawtooth skin marking device for large component jointing, used in the above-mentioned repairing method, comprising:

[0024] The block base is designed as a stepped structure with placement holes and a serrated skin limiting clamping plate;

[0025] A drawing pen, which is arranged through the placement hole;

[0026] The adjusting mechanism is installed on the support block base and is used for adjusting the relative position of the drawing pen.

[0027] As a further solution of the present invention: the adjustment mechanism is a limit bolt, which contacts the side of the marker pen to facilitate the adjustment and positioning of the marker pen.

[0028] As a further solution of the present invention: the serrated skin limiting clamping plate is integrally formed with the support block base, and the serrated skin limiting clamping plate protrudes from the lower surface of the support block base.

[0029] As a further solution of the present invention: the liner pen is an eccentric liner pen, and the tip of the liner pen is located on the side.

[0030] Compared with the prior art, the beneficial effects of this application are:

[0031] 1. The present invention can solve the problem that different components are installed on different frames during the assembly stage, the assembly errors are dispersed, and there is no unified benchmark.

[0032] 2. The present invention can solve the problem that the gap between the sawtooth skins is uneven and difficult to be adjusted in the best posture during docking and posture adjustment.

[0033] 3. The present invention can solve the problem of how to quickly and accurately assemble components when they are butted together without a frame or pallet reference state.

[0034] 4. The present invention breaks the limitation of the existing method of only reducing the manufacturing error of parts, and starts from reducing the assembly error and docking error of components, so that the serrated skin repair scheme can be applied to the actual production of aircraft component docking.

[0035] The present application is further described below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0037] In the attached picture:

[0038] Figure 1 This is a schematic diagram of the sawtooth pallet tooling for this application;

[0039] Figure 2 This is a schematic diagram of the pose adjustment point cloud processing interface for this application;

[0040] Figure 3 A schematic diagram for determining key parameters of the line drawing device for this application;

[0041] Figure 4 This is a schematic diagram of the sawtooth edge drawing device for the sawtooth skin of this application;

[0042] Figure 5 This is a schematic diagram of the sawtooth skin rounded edge drawing device of this application;

[0043] Figure 6 This is a schematic diagram of a device for drawing lines at small distances on the sawtooth edge of a sawtooth skin in this application.

[0044] The reference numerals in the figure are: 1. serrated clamping plate; 2. skeleton clamping plate; 3. marking pen; 4. limiting bolt; 5. support block base; 6. serrated skin limiting clamping plate; 7. clamping bolt through hole; 8. concave rounded edge of tooling; 9. convex rounded edge of tooling; 10. eccentric marking pen. DETAILED DESCRIPTION

[0045] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0046] In the first aspect, the present invention discloses a method for repairing a sawtooth skin in a large component joint, see the attached Figure 1-6 In order to better understand the technical content of the present invention, a specific example is given and the attached drawings are used to illustrate the following. It contains a clean edge serrated wall panel as a repair reference and a wall panel to be repaired with a processing allowance, a repair tool in the component assembly stage and the component docking stage, and a point cloud processing interface.

[0047] A sawtooth pallet tooling 1 is developed that is consistent with the curvature of the sawtooth siding of the component and follows the shape, and the sawtooth pallet is positioned based on the skeleton pallet 2 of the component assembly jig. After the sawtooth siding is delivered with the margin, the sawtooth skin is manually trimmed through the sawtooth pallet 1 after the siding skeleton is assembled. The docking components are constructed on different assembly jigs during the component assembly stage, and the two are unified in the shape trimming benchmark through the sawtooth pallet 1 whose outer surfaces follow each other and have the same curvature change. After trimming, the margin edge skin still retains at least three-quarters of the margin.

[0048] After the parts are hoisted into place, the posture is adjusted according to the horizontal measurement points. Before docking, the TSCAN adapter needs to be used to perform a contour scan on the sawtooth skin. In order to scan the thickness end face of the sawtooth skin, a handheld scanning device is required to scan obliquely at forty-five degrees above the sawtooth. After generating the point cloud, traverse the point set on each trace line, use KD-TREE to narrow the search area, set a distance threshold, and divide each point and its adjacent points within the threshold number distance into an area. Extract the boundary points of the sawtooth skin based on the discrete curvature analysis results of the points. Use the CAA function to add a point cloud processing module in CATIA. The specific implementation logic is as follows:

[0049] 1) Declare a two-dimensional array LIST[i][j], where i represents the i-th scan line and j represents the j-th point.

[0050] 2) When j < 3, n = 1, search LIST[i][n], LIST[i][n+1] ... LIST[i][j+2]. Put the above points into a new empty array.

[0051] 3) j = j + 2 and assign the current value of j to n. Then loop through the array element search and storage in step 2) until the LIST[i][j + 2] array is empty, and then traverse to the last element of the array that is not empty.

[0052] 4) The array lists obtained in steps 2) and 3) are looped again, and the GetAngle() function is used to compare the angle of the line connecting the adjacent elements with the set threshold for each point element to obtain the unique sawtooth edge point in the array list.

[0053] 5) Set i=i+1 and repeat 2), 3), and 4) until the array is empty. Add the obtained edge points to the instance array CATLIST(CATISpecObject_var)oLIS, call GetY() under the CATIMeasure_var interface to obtain the Y coordinate component of the point in the aircraft coordinate system, and store it in the one-dimensional array Math[], which is mapped to the corresponding element of oLIST.

[0054] 6) Compare Math[i] with Math[i+1]. If Math[i] is larger, swap the order of the two. If Math[i+1] is larger, continue executing. After i=i+1, loop this step again until all the elements of the one-dimensional array are traversed.

[0055] 7) After step 6), the largest element of the array has been stored at the end of the array through recursive sorting. Subtract 1 from the total number of array elements and continue with step 6).

[0056] 8) At this time, the purpose of step 7) is to store the element with the largest Y value among the remaining elements in the second to last position of the array, and so on, until the iteration is completed. During the execution process, as the order of the elements of the one-dimensional array Math[] is changed, the oLIST elements should be changed in the same way.

[0057] After sorting, the CreateLine() function under the CATIGSMFactory_var interface is used to reconstruct the curve and connect them sequentially according to the order of oLIST elements.

[0058] The reconstructed connection results of each skin boundary line are used for motion simulation as a reference for posture adjustment.

[0059] In the docking state, the method of drawing lines and then manually repairing is adopted. This method has the advantages of being convenient, flexible, and able to find a reference.

[0060] 1) When the gap of the serrated skin is uniform, withdraw the CNC positioner by Xmm in the reverse direction, and use the serrated edge drawing device and the rounded corner drawing device to draw the serrated skin. The size of the serrated edge drawing device is determined by four parameters (α, d, b, w). α is the angle between the serrated edge and the heading after the serrated skin is projected onto the horizontal plane of the aircraft structure, d is the distance the CNC positioner is dragged along the heading when drawing the line, and to ensure the stability of the line drawing, the length of the serrated edge drawing device extending out of the serrated edge is d*tanα+30 (mm). Because the reference of the serrated edge drawing device is the edge of the clean edge skin, b is the thickness of the wall panel, and the thickness of the limit card 6 of the serrated edge drawing device is b-0.2 (mm). Because the clean edge skin is also manually trimmed and the end face is a low curvature surface, w is the width input of the tooling support block base 5, and to reduce the error, the width of each support block is 10mm. In order to make it easy for personnel to carry and apply force, the height of the support block base 5 should be 20mm. The marking pen 3 is inserted from the support block placement hole to mark the product, and the side wall has a limiting bolt 4 to adjust the position of the marking pen. The distance between the axis of the marking pen and the fitting surface of the limiting card plate 6 and the serrated edge is d*tanα. In order to increase the fault tolerance and the degree of freedom of adjusting the drawing, a number of -0.1, +0.2, +0.5, +1, and +1.5 are set based on the calculated d*tanα size value. The general principle is: the edges of the serrated skin are aligned with the angle between the tooling limiting card plate 6 and the support block base 5. Use a marking pen to draw local lines during movement, and then connect the local lines as a whole. The advantage is that the deviation between the fitting end face of the support block and the net edge skin and the actual shape of the net edge skin can be reduced.

[0061] 2) The size of the convex and concave fillet support block tooling is determined by two parameters (R, h), R is the radius parameter of the serrated convex and concave fillets, and h is the length of the straight edges on both sides of the fillet of the support block. The straight edges are aligned with the drawn straight lines, and the bolts are fixed through the clamping bolt holes 7. The concave fillet edges 8 and convex fillet edges 9 of the tooling are drawn along the serrated fillet edges.

[0062] 3) Considering the calculation, measurement and repair errors, the last repair may be a small-scale local manual fine repair, so a small-scale sawtooth skin drawing device is specially designed to perform the last fine repair and drawing to meet the sawtooth skin repair quality. The distance between the end point of the drawing and the end face side of the sawtooth skin limit clamp 6 is controlled by the eccentric drawing pen 10.

[0063] Second, see Figure 4 or Figure 6 The present invention discloses a sawtooth skin line drawing device for large component jointing, which is used in the above-mentioned repairing method, and comprises:

[0064] The support block base is designed as a stepped structure, with a placement hole and a serrated skin limiting card plate; the serrated skin limiting card plate is integrally formed with the support block base, and the serrated skin limiting card plate protrudes from the lower surface of the support block base.

[0065] A drawing pen, which is arranged through the placement hole;

[0066] The adjusting mechanism is installed on the support block base and is used to adjust the relative position of the marker pen. The adjusting mechanism is a limit bolt, which contacts the side of the marker pen to facilitate the adjustment and positioning of the marker pen.

[0067] Preferably, the marker pen is an eccentric marker pen, and its tip is located on the side. The last trimming may be a small-sized local manual fine trimming. A small-sized sawtooth skinning marking device is specially designed for the last fine trimming and marking. The marker pen tip is located on the side, which is convenient for small-sized local marking.

[0068] So far, the purpose of the present invention has been achieved.

[0069] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for repairing serrated skin in large component jointing, characterized in that: The steps include: Unified repair standards for different parts: During the assembly stage, different component assembly jigs are set with consistent curvature and serrated pallet tooling that follows each other. The skins of different components are repaired based on this tooling, and the components are delivered with margins after repair; Motion simulation based on skin reconstruction: Scan the skin contour with laser measuring equipment, import the measured points into CATIA, reconstruct the skin contour based on the imported points through secondary development technology, perform motion simulation after reconstruction, and find local interference points on the path; The sawtooth skin drawing device is designed according to the parameters of skin thickness, trimming position, skin projection and heading angle. The line drawing is carried out quickly and accurately in the final assembly stage according to the tooling, and the trimming is carried out according to the drawn lines.

2. The method for repairing the sawtooth skin in the large component joint according to claim 1 is characterized in that: The unified repairing benchmarks for different components specifically include the following steps: According to the digital model of the net edge skin of the reference component, the manufacturing size of the net edge serrated skin is the deviation from the design requirement, the skin is fixed on the component assembly jig and a serrated clamping plate following the theoretical model of the net edge skin is set; The remaining skin of another component is fixed on the assembly jig of another component and fits with the remaining edge serrated pallet, and the remaining edge serrated pallet has the same shape and curvature as the net edge skin serrated pallet; The theoretical model shapes and curvature changes of the serrated pallets of the two components are consistent with each other, and the serrated skins of different components are repaired along the pallets to form a unified benchmark; after the skin with allowance is repaired, three-quarters of the allowance is left, and the repair will continue when the components are docked.

3. The method for repairing the serrated skin in the large component joint according to claim 1 is characterized in that: The motion simulation specifically includes the following steps: In the component posture adjustment stage, after the component is put on the shelf, the skin contour measurement system is used to scan the skin contour of the net edge and the residual edge sawtooth. The measurement system consists of TSCAN, a laser tracker, and corresponding control software. TSCAN is used to scan the skin sawtooth obliquely above the skin to obtain a point cloud model containing several scan lines. Traverse the point set on the scan line, use KD-TREE to narrow the search area, set a point position threshold, and divide each point and its adjacent threshold number of points into a region; extract the boundary points of the sawtooth skin based on the discrete curvature analysis results of the points, set an angle threshold, and use a point P0 in a divided area as a reference to screen out the points P1 and P2 adjacent to it on both sides, calculate the angles of P0 P1 and P0 P2, and compare them with the threshold to determine the sawtooth boundary points; The Y-component coordinate values ​​of the points in the aircraft coordinate system are recursively sorted and connected in sequence; the boundary lines of the residual skin and the net edge reconstruction are projected onto the horizontal plane of the aircraft digital model, and the uniformity of the gap of the serrated skin after docking in the current attitude can be obtained; the aircraft attitude is adjusted according to the results.

4. The method for repairing serrated skin in large component jointing according to claim 1 is characterized in that: The line drawing and repairing specifically comprises the following steps: Usually the sawtooth skin is in the form of frame docking or plate overlap. When the gap of the sawtooth skin is uniform, the CNC positioner is withdrawn Xmm in the reverse direction, and the sawtooth skin is marked with a T-type support block tooling and a convex and concave rounded support block tooling; the marking pen is inserted into the support block placement hole to mark the product, and the side wall is provided with a limit bolt to adjust the position of the marking pen. The size of the convex and concave fillet support block tooling is determined by two parameters (R, h), where R is the radius of the sawtooth convex and concave fillets, and h is the length of the straight edges on both sides of the fillet of the support block; the straight edges are fitted to the above-mentioned drawn lines, and the lines are drawn along the fillet edges.

5. The method for repairing the sawtooth skin in the large component joint according to claim 4 is characterized in that: The size of the T-type support block tooling is determined by four parameters (α, d, b, w); α is the angle between the serrated edge and the heading after the serrated skin is projected onto the horizontal plane of the aircraft structure, d is the distance the CNC positioner withdraws along the heading when drawing a line, b is the wall panel thickness input, and w is the support block width input.

6. A sawtooth skin marking device for large component jointing, characterized in that: Used in the repairing method as described in any one of claims 1 to 5 above, comprising: The block base is designed as a stepped structure with placement holes and a serrated skin limiting clamping plate; A drawing pen, which is arranged through the placement hole; The adjusting mechanism is installed on the support block base and is used for adjusting the relative position of the drawing pen.

7. The sawtooth skin marking device for large component jointing according to claim 6 is characterized in that: The adjustment mechanism is a limiting bolt, which contacts the side of the marker pen to facilitate the adjustment and positioning of the marker pen.

8. The sawtooth skin marking device for large component jointing according to claim 7 is characterized in that: The sawtooth skin limiting clamping plate is integrally formed with the support block base, and the sawtooth skin limiting clamping plate protrudes from the lower surface of the support block base.

9. The sawtooth skin marking device for large component jointing according to any one of claims 6-8, characterized in that: The drawing pen is an eccentric drawing pen, and the pen tip is located at the side.

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