Aircraft integrated structure digital repair and matching system and method

Abstract

The present invention provides an aircraft integrated structure digital repair and fitting system and method, belonging to the technical fields of aviation manufacturing engineering and aircraft assembly. The present invention combines digital measurement, virtual assembly and numerical control machining technologies, formulates a process plan for adapting the surplus trimming of integrated parts based on quantity coordination, eliminates the cumulative errors in the forming and assembly processes of parts through digital trimming, significantly reduces the requirements for the manufacturing accuracy of parts by the non-jig assembly technology, and expands the application scope of the non-jig assembly technology. The present invention also takes into account the manufacturing cost and efficiency, greatly shortens the production preparation cycle, realizes the rapid trial production of aircraft, promotes the iteration and upgrade of aircraft models, and provides technical support for the leap of the capabilities of future combat aircraft such as high altitude, high speed, high maneuverability and high stealth.

Description

Technical Field

[0001] The present invention belongs to the technical fields of aviation manufacturing engineering and aircraft assembly, and relates to an integrated structure digital repair and fitting system and method for performing component repair and fitting work based on digital coordination during the aircraft assembly process. Background Art

[0002] To achieve wide speed range coverage, significant changes have occurred in both the power form and structure of aircraft. The combined power has become the future development trend, which has also led to significant changes in the structural form of aircraft compared with conventional models. The application of the multi-functional integrated structure has created conditions for improving the rigidity, strength, and fatigue life of the airframe, reducing the number of connecting parts and the weight of the aircraft, and breaking through the limitations of the traditional aircraft structural layout. The aircraft replacement in various countries is getting faster and faster, and rapid development has become the main theme of the times. There is an urgent need to develop a digital repair and fitting method suitable for the assembly of the aircraft integrated structure to achieve rapid repair cutting and assembly of process allowances at the assembly site, promote the iteration and upgrade of aircraft models, and provide technical support for the leap of future combat aircraft in capabilities such as high altitude, high speed, high maneuverability, and high stealth.

[0003] The integrated large structure integrates multiple functions, such as load-bearing and aerodynamic shape integrated parts, which avoids many components entering the assembly process, promoting the development of the no-fixture assembly process. The no-fixture assembly technology is in the ascendant. Its process idea is to use the geometric features of the components themselves to achieve the positioning and clamping between the mating parts, reducing the types and quantities of assembly fixtures, thereby reducing the production preparation and manufacturing cycle, lowering the production cost, and at the same time achieving flexible production and improving product flexibility, quality, and assembly efficiency. To meet the assembly accuracy requirements, the current mainstream no-fixture assembly technology is based on the precise manufacturing of components, which not only increases the manufacturing cost of components but also prolongs the manufacturing cycle of components, and has little effect on shortening the total aircraft development cycle. Although the integrated structure reduces the number of components and to a certain extent reduces the need for positioning and clamping during the assembly process, there are still assembly coordination relationships. For example, if the manufacturing accuracy of components is blindly improved to ensure the application of the no-fixture assembly process, it will inevitably increase the manufacturing cost and cycle of components. The aircraft assembly coordination relationship is complex and the process flow is long. The traditional process reserves allowances in the key assembly and mating areas to eliminate the influence of cumulative errors and ensure the mating accuracy. Therefore, to ensure the high-precision no-fixture assembly of the aircraft integrated structure while taking into account the manufacturing cost and efficiency, it is imperative to develop a digital repair cutting method by referring to the traditional allowance repair cutting process and expand the application range of the no-fixture assembly process.

[0004] The present invention proposes a digital repair and fitting method for the aircraft integrated structure. According to the machining allowances determined by digital measurement and virtual assembly, under the real-time tracking and feedback of the digital measurement instrument, the precise repair and fitting of the key assembly and mating features of the aircraft are completed, ensuring the assembly and mating accuracy while reducing the dependence of the aircraft assembly work on fixtures, shortening the production preparation cycle, and improving manufacturing economy. Summary of the Invention

[0005] The core of the digital trimming process for the integrated structure of an aircraft is that for non-critical areas that have no impact on the assembly quality, the degrees of freedom of the cooperating components are restricted by the product's own features (such as holes, frames, beams, surface profiles, etc.) to achieve the positioning of aircraft components. For critical areas with high-precision fits, taking into account the part fit accuracy, manufacturing cost, and cycle, machining allowances are left at the ends of the parts that are convenient for repair. Based on digital coordination, digital measurement and virtual assembly technologies are used to determine the remaining allowances to be repaired, and the allowances are trimmed through on-site machining methods, thereby eliminating the influence of cumulative errors in part manufacturing and assembly positioning and meeting the precise repair requirements of critical mating areas.

[0006] A digital repair system for the integrated structure of an aircraft, as Figure 1 shown, includes a numerical control machining device 1, a scanner 2, a digital measurement support 3, a machining support 4, a tracking measuring instrument 6, and a flexible clamping tooling 7 for parts.

[0007] The gantry frame of the numerical control machining device 1 can move along the ground guide rails. The digital measurement support 3 and the machining support 4 are installed on the upper crossbeam of the numerical control machining device 1 and can move horizontally along the guide rails on the upper crossbeam of the numerical control machining device 1. The digital measurement support 3 and the machining support 4 can move up and down by themselves. The scanner 2 is installed at the lower end of the digital measurement support 3 and is used to measure the outer surface of the part to be machined 5 and the tracking identification points 8 thereon. The tracking measuring instrument 6 is arranged at the edge of the numerical control machining device 1; the flexible clamping tooling 7 for parts is arranged within the machining and measurement areas of the numerical control machining device 1 and is used to support and clamp the part to be machined 5. Tracking identification points 8 are provided on the part to be machined 5.

[0008] Different from a conventional five-axis machining machine tool, the digital measurement support 3 and the machining support 4 are integrated on the upper crossbeam of the numerical control machining device 1. Among them, the machining support 4 is similar to a conventional five-axis machine tool and is used for trimming the allowances of parts. The digital measurement support 3 is used to connect and integrate digital measurement instruments such as the scanner 2. It not only drags the digital measurement instruments to complete the measurement tasks, but also provides a coordinate reference for the data stitching of the measurement data of devices such as the scanner 2 during large-size measurements. The size of the part to be machined can reach several meters, while the single-frame measurement of the scanner 2 is generally less than 0.5 meters, and multiple scans are required to complete the overall measurement task through data stitching. Data stitching has a great impact on the measurement accuracy. With the accuracy of the numerical control machining device 1 and the digital measurement support 3 as a guarantee, a data stitching reference is provided for multiple groups of measurement data of the scanner 2 to achieve high-precision measurement of large parts.

[0009] The scanner 2 is used to measure the external surface of the part to be machined 5 and track the tracking identification points 8. The tracking identification points 8 cooperate with the tracking measuring instrument 6 to facilitate the subsequent rapid establishment of the aircraft coordinate system. The actual state point cloud data of the product formed is aligned and unified into the aircraft part coordinate system through coordinate alignment. Through reverse modeling and virtual assembly, the position and machining amount of the area to be machined are obtained for use in subsequent processes.

[0010] Since the scanner 2 has low efficiency in determining the aircraft part coordinate system and does not match the rapid measurement requirements during the machining process, the tracking measuring instrument 6 makes up for this defect. The tracking measuring instrument 6 is arranged near the machining area and is accurately calibrated with the numerical control machining equipment 1 to unify the coordinate system. It is used to collect the position information of the tracking identification points 8 on the part to be machined 5 in real time. By fitting with the data of the tracking identification points 8 provided by the scanner 2, it can quickly determine the aircraft part coordinate system and track the position and attitude of the part to provide closed-loop control data support for the high-precision positioning and trimming of the part, ensuring the high-precision trimming of the product.

[0011] The flexible part clamping fixture 7 only needs to complete the reliable clamping of the part to be machined 5 and has no positioning function. The product positioning is ensured by digital measurement means, but it needs to be highly flexible to adapt to the clamping work of different products. The main frame of the flexible part clamping fixture 7 is a common part with a certain adjustment ability. A small number of process parts connected to the product can be designed and manufactured according to the product, facilitating the quick and reliable clamping of the product.

[0012] The beneficial effects of the present invention: The present invention combines digital measurement, virtual assembly and numerical control machining technologies, and formulates a process plan for adapting to the integrated part allowance trimming based on quantity coordination. By means of digital trimming, the cumulative errors in the part forming and assembly processes are eliminated, significantly reducing the requirements for the manufacturing accuracy of parts by the non-jig assembly technology and expanding the application scope of the non-jig assembly technology. The digital repair and matching process for the aircraft integrated structure takes into account both manufacturing cost and efficiency, greatly shortening the production preparation cycle, realizing the rapid trial production of the aircraft, promoting the iteration and upgrading of aircraft models, and providing technical support for the leap of the future combat aircraft in capabilities such as high altitude, high speed, high maneuverability and high stealth. Description of the Drawings

[0013] Figure 1 It is a composition diagram of the digital repair and matching system for the aircraft integrated structure.

[0014] Figure 2 It is a process flow diagram of the digital repair and matching process for the aircraft integrated structure.

[0015] In the figure: 1 Numerical control machining equipment; 2 Scanner; 3 Digital measurement support; 4 Machining support; 5 Part to be machined; 6 Tracking measuring instrument; 7 Flexible part clamping fixture; 8 Tracking identification point. Detailed Embodiment

[0016] The following further explains the specific implementation manners of the present invention in combination with embodiments and the drawings, but is not used to limit the present invention.

[0017] As Figure 1 shown, an aircraft integrated structure digital repair and fitting system includes a numerical control machining device 1, a scanner 2, a digital measurement support 3, a machining support 4, a tracking measuring instrument 6, and a flexible clamping tooling 7 for parts. The gantry frame of the numerical control machining device 1 can move along the ground guide rail. The digital measurement support 3 and the machining support 4 are installed on the upper cross beam of the numerical control machining device 1 and can move along the guide rail of the upper cross beam of the numerical control machining device 1, and can move up and down by itself. The scanner 2 is installed at the lower end of the digital measurement support 3 and is used to measure the outer surface of the part 5 to be machined and the tracking identification points 8 thereon. The tracking measuring instrument 6 is arranged at the side of the numerical control machining device 1; the flexible clamping tooling 7 for parts is arranged in the machining and measuring area of the numerical control machining device 1 and is used to support and clamp the part 5 to be machined. Tracking identification points 8 are arranged on the part 5 to be machined.

[0018] The process flow of adopting the above aircraft integrated structure digital repair and fitting system is as Figure 2 shown, and the specific steps are as follows:

[0019] (1) Preparation of trimming process data

[0020] Move the machining support 4 to one end of the upper cross beam of the numerical control machining device 1, and the scanner 2 is installed at the lower end of the digital measurement support 3 for standby. The part 5 to be machined is fixed on the flexible clamping tooling 7 for parts to ensure reliable clamping. The digital measurement support 3 drives the scanner 2 to successively measure the outer surface of the part 5 to be machined and the tracking identification points 8 that cooperate with each other. Each time of measurement, the position and attitude information of the machining support 4 are read simultaneously, and the information is melted to realize high-precision splicing of multiple groups of measurement data, and then the best fit is carried out with the theoretical model. The measurement data is converted into the aircraft part coordinate system, and finally, after processing, a measurement parameter library is formed. Based on the measurement parameter library, the data of the area to be trimmed is extracted, and through reverse modeling and virtual assembly, the position and machining amount of the area to be machined are obtained for the next trimming process planning. At the same time, the coordinate information of the tracking identification points 8 on the part 5 to be machined is extracted and provided to the tracking measuring instrument 6 for subsequent rapid positioning of parts.

[0021] (2) Trimming process planning

[0022] To avoid irreparable quality losses caused by excessive cutting during the repair and fitting of parts, a successive approximation method is adopted for repair and fitting. The repair and fitting process is divided into rough machining to remove the surplus, finish machining for correction, and finishing to ensure the surface finish of the final machining and remove the remaining surplus. A machining program is compiled. According to the results of the preparation stage of the cutting process data, most of the process surplus is removed by rough machining. Generally, about 0.5 mm of surplus is left at the skin butt joint for the next cutting; about 0.4 mm of surplus is removed by finish machining for correction; and finishing ensures the surface finish of the final machining surface and removes the remaining surplus.

[0023] (3) Clamping and fixing of parts

[0024] According to the machining requirements of the cutting area, adjust the position of the part 5 to be machined to facilitate measurement and cutting, and use the flexible clamping tooling 7 for parts to clamp the part 5 to be machined.

[0025] (4) Digital positioning of parts

[0026] Before using the tracking measuring instrument 6, it is necessary to perform system calibration with the numerical control machining equipment 1 to determine the relative position relationship between the tracking measuring instrument 6 and the numerical control machining equipment 1 and unify the coordinate system. Then, the tracking measuring instrument 6 measures the tracking identification points 8 arranged on the part 5 to be machined, confirms the position relationship between the numerical control machining equipment 1 and the part 5 to be machined, and further adjusts the machining program determined in the cutting process plan.

[0027] (5) Rough machining to remove the surplus

[0028] According to the adjusted machining program, use the numerical control machining equipment 1 to remove most of the surplus of the part 5 to be machined. For thin-walled parts, pay attention to adjusting the cutting parameters during the machining process to avoid excessive vibration of the parts affecting the cutting. If necessary, increase the number of passes.

[0029] (6) Digital inspection and virtual assembly verification

[0030] After rough machining, to avoid excessive cutting during the repair and fitting of parts and cause quality deviation, keep the position of the part 5 to be machined unchanged, use the scanner 2 to measure the machining area of the part 5 to be machined again. After data processing, coordinate system transformation, reverse modeling, and virtual assembly, confirm the actual surplus of the machining area. According to the actual surplus value, correct the subsequent finish machining and finishing programs to finally ensure the cutting accuracy and surface quality of the part 5 to be machined.

[0031] (7) Finish machining for correction

[0032] According to the results of step (6), adjust the finish machining cutting amount, correct the machining program, and complete the finish machining for correction work. During the machining process, the tracking measuring instrument 6 measures the coordinate values of the tracking identification points 8 in real time and judges whether the position of the part 5 to be machined has changed. If it has changed, stop cutting and adjust according to the measured values.

[0033] (8) Finishing

[0034] The last remaining allowance is removed by finishing. During the machining process, pay attention to adjusting the cutting parameters to ensure that the cutting surface roughness meets the standard and complete the final trimming work.

[0035] (9) Machining completed

[0036] After the product is trimmed, it is delivered for assembly and use after passing the acceptance inspection.

Claims

1. An aircraft integrated structure digital repair and fitting system, characterized in that The system includes a numerically controlled machining device (1), a scanner (2), a digital measurement support (3), a machining support (4), a tracking measuring instrument (6), and a flexible clamping fixture for parts (7). The gantry frame of the numerically controlled machining device (1) can move along the ground guide rail. The digital measurement support (3) and the machining support (4) are installed on the upper crossbeam of the numerically controlled machining device (1) and can move horizontally along the guide rail on the upper crossbeam of the numerically controlled machining device (1). The digital measurement support (3) and the machining support (4) can move up and down by themselves. The flexible clamping fixture for parts (7) is arranged in the machining and measuring area of the numerically controlled machining device (1) and is used to support and clamp the parts to be machined (5). The scanner (2) is installed at the lower end of the digital measurement support (3) and is used to measure the outer surface of the parts to be machined (5) and the tracking identification points (8) thereon. The tracking measuring instrument (6) is arranged at the side of the numerically controlled machining device (1) and is used to collect the position information of the tracking identification points on the parts to be machined in real time.

2. A repair method using the aircraft integrated structure digital repair and fitting system as described in claim 1, characterized in that, The method includes the following steps: 1) Preparation of trimming process data Move the machining support (4) to one end of the upper crossbeam of the numerically controlled machining device (1), and install the scanner (2) at the lower end of the digital measurement support (3) for standby. Fix the parts to be machined (5) on the flexible clamping fixture for parts (7) to ensure reliable clamping. The digital measurement support (3) drags the scanner (2) to successively measure the outer surface of the parts to be machined (5) and the tracking identification points (8) that cooperate with each other. Each time of measurement, read the position and attitude information of the machining support at the same time, and melt the information to achieve high-precision splicing of multiple groups of measurement data. Then perform the best fit with the theoretical model, convert the measurement data to the aircraft parts coordinate system, and finally form a measurement parameter library after processing. Based on the measurement parameter library, extract the data of the area to be trimmed. Through reverse modeling and virtual assembly, obtain the position and machining amount of the area to be machined for the next trimming process planning. At the same time, extract the coordinate information of the tracking identification points (8) on the parts to be machined (5) and provide it to the tracking measuring instrument (6) for subsequent rapid positioning of the parts. 2) Trimming process planning To avoid excessive cutting during parts repair and cause irreparable quality losses, the successive approximation method is used for repair. The repair process is divided into rough machining to remove the surplus, finish machining for correction, and finish machining, and the machining program is compiled. 3) Clamping and fixing of parts According to the machining requirements of the trimming area, adjust the position of the parts to be machined (5) to facilitate measurement and trimming. Use the flexible clamping fixture for parts (7) to clamp the parts to be machined (5). 4) Digital positioning of parts Before using the tracking measuring instrument (6), it is necessary to perform system calibration with the numerically controlled machining device (1) to determine the relative position relationship between the tracking measuring instrument (6) and the numerically controlled machining device (1) and unify the coordinate system. Then the tracking measuring instrument (6) measures the tracking identification points (8) arranged on the parts to be machined (5), confirms the position relationship between the numerically controlled machining device (1) and the parts to be machined (5), and then adjusts the machining program determined in the trimming process planning. 5) Rough machining to remove the surplus According to the processing program adjusted in step 4), a numerical control machining device (1) is used to remove most of the surplus of the workpiece to be machined (5). 6) Digital inspection and virtual assembly verification After rough machining, to avoid excessive cutting during the fitting of the workpiece and causing quality deviation, the position of the workpiece to be machined (5) is kept unchanged, and a scanner (2) is used to measure the machining area of the workpiece to be machined (5) again. After data processing, coordinate system transformation, reverse modeling and virtual assembly, the actual surplus of the machining area is confirmed. According to the actual surplus value, the subsequent finish machining and finishing machining programs are corrected to finally ensure the trimming accuracy and surface quality of the workpiece to be machined (5). 7) Finish machining correction According to the result of step 6), the finish machining cutting amount is adjusted, the machining program is corrected, and the finish machining correction work is completed. During the machining process, a tracking measuring instrument (6) measures the coordinate values of the tracking identification points (8) in real time and judges whether the position of the workpiece to be machined (5) has changed. If it has changed, the cutting is stopped and adjusted according to the measured values. 8) Finishing machining The remaining surplus is removed by finishing machining. During the machining process, pay attention to adjusting the cutting parameters to ensure that the cutting surface roughness meets the standard, and complete the final trimming work. 9) Machining completion After the product is trimmed, it is delivered for assembly and use after passing the acceptance inspection.

3. The repair method according to claim 2, characterized in that, In step 2), according to the result of the trimming process data preparation stage in step 1), most of the process surplus is removed by rough machining, and a 0.5 mm surplus is left at the skin butt joint for the next cutting; 0.4 mm of surplus is removed by finish machining correction; the finishing machining ensures the surface finish of the final machining and trims the remaining surplus.

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