A rapid recognition method for aircraft sheet metal parts models based on thickness dimension features

Abstract

The present invention relates to the field of aviation manufacturing technology, and discloses a method for quickly identifying aircraft sheet metal part models based on thickness dimensional features, including parsing, processing and converting given part model data, discretizing the part's geometric surface, extracting or calculating the thickness dimensional features of each point on the surface, and realizing sheet metal part model recognition by checking the consistency between the part's comprehensive thickness dimension and the reference thickness dimension. The method can efficiently and accurately screen out sheet metal part models from aircraft design models, solving the problems of heavy workload, low efficiency, and easy errors in current manual screening methods, shortening the aircraft manufacturing process division of labor and the production preparation cycle of related links, and providing more accurate input for sheet metal part process design; at the same time, a calculation method for the comprehensive thickness dimension and the fillet thickness dimension is proposed, which effectively avoids performing a large number of thickness dimension feature calculations on the model while ensuring accuracy, thereby improving calculation efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of aviation manufacturing, in particular to a method for quickly identifying an aircraft sheet metal part model based on thickness size features. Background Art

[0002] Sheet metal parts are widely used in aircraft structures due to their light weight, high strength, low cost, and ease of production. According to statistics, sheet metal parts account for up to 50% of an aircraft's overall structure. Sheet metal process design is a critical factor in determining the quality and efficiency of sheet metal part production, and this requires the issuance of accurate part design models to sheet metal process designers. However, aircraft design models are typically organized by product function or structure rather than by part type. This organization of design models is inconsistent with the current division of labor and organizational structure within specialized aircraft factories (such as sheet metal shops, machining shops, and composite materials shops). Consequently, aircraft design models must be classified, screened, and distributed to the appropriate specialized factories before subsequent part process design and manufacturing can proceed. The large number of aircraft sheet metal part models, their complex and diverse geometric shapes, and their similarities to other part models make accurate and efficient identification of these models a significant challenge.

[0003] In response to the above problems, aviation manufacturing companies currently mainly use manual screening to identify sheet metal part models, which has shortcomings such as large workload, low efficiency, and easy misjudgment. From the analysis of the current research status at home and abroad, the methods proposed in some literatures have certain reference value for the identification of aircraft sheet metal part models, but at present, mature technical solutions and methods that can directly solve the rapid identification of aircraft sheet metal part models have not yet been reported. For example, the patent "A method for automatically identifying face difference surfaces of sheet metal parts based on secondary development of UG NX (authorization announcement number: CN113688476B, authorization announcement date: 2021.11.23)" can automatically identify all face difference surfaces on sheet metal parts; the patent "A method for identifying part processing features based on machine vision learning and recognition (authorization announcement number: CN114067231B, authorization announcement date: 2022.05.10)" uses machine learning methods to solve the identification of complex processing features and new processing features; ... UG NX (authorization announcement number: CN114067231B, authorization announcement date: 2022.05.10)" uses machine learning methods to solve the identification of complex processing features and new processing features; the patent "A method for automatically identifying face difference surfaces of sheet metal parts based on UG NX (authorization announcement number: CN113688476B, authorization announcement date: 2021.11. The patent "Method and Device for Automatic Identification and Positioning of Sheet Metal Parts Based on DXF (Authorization Announcement No.: CN113111458B, Authorization Announcement Date: 2022.10.21)" can identify and locate irregular sheet metal graphics on metal sheets, and is mainly suitable for two-dimensional sheet metal parts cut by laser; the patent "Method and Device for Identifying Rotary Processing Features (Authorization Announcement No.: CN110837694B, Authorization Announcement Date: 2023.10.20)" can identify rotary parts and rotary processing features. The focus of the above invention patents is to solve the problem of part processing feature recognition, focusing on identifying local processing features with certain engineering semantics from a given part model, rather than identifying and classifying part types. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for quickly identifying aircraft sheet metal part models based on thickness dimensional features, so as to solve the problems of heavy workload, low efficiency and easy misjudgment in manual screening of sheet metal part models.

[0005] The present invention is implemented through the following technical solution: a method for quickly identifying aircraft sheet metal part models based on thickness dimension features, which realizes sheet metal part model identification by checking the consistency of the comprehensive thickness dimension of the part with the reference thickness dimension. The specific steps include:

[0006] Step S1: Batch read the part models to be identified according to the folder path set by the user ,in , Indicates the part model number, Indicates the total number of part models, set , set two sets with initial values ​​​​to be empty and , used to record non-sheet metal part models and sheet metal part models respectively;

[0007] Step S2: If , then calculate the part model Reference thickness dimensions ; Otherwise, execute step S9;

[0008] Step S3: For the part model to be identified , calculate the comprehensive thickness dimension of the part model ;

[0009] Step S4: Check the consistency between the comprehensive thickness dimension and the reference thickness dimension. If the consistency requirement is not met, the part model is judged to be If it is a non-sheet metal part, Add to non-sheet metal part model collection Then set , return to step S2;

[0010] Step S5: traverse the part model Round feature in , , Indicates the serial number of the fillet feature, Indicates the total number of round features; if , then go to step S8, otherwise set ;

[0011] Step S6: , calculate the fillet feature Thickness ; Otherwise, execute step S8;

[0012] Step S7: Check the consistency between the fillet thickness and the reference thickness. If the consistency is not satisfied, determine the part model. If it is a non-sheet metal part, Add to non-sheet metal part model collection and set , go to step S2, otherwise set , return to step S6;

[0013] Step S8: Determine the part model For sheet metal parts, Add to Sheet Metal Part Model Collection and set , go to step S2;

[0014] Step S9: Output non-sheet metal part model sets separately and sheet metal part model collections All models in .

[0015] In order to better implement the present invention, further, the reference thickness size in step S2 The calculation steps are as follows:

[0016] Step S21: traverse the part model The geometric surface in , , Indicates the geometric surface number, Indicates the total number of geometric faces;

[0017] Step S22: Start by looping and calculating each geometric face Area , until End the loop, and then find the geometric surface with the largest area by comparing the obtained area values ;

[0018] Step S23: Geometric surface Discretize according to the set accuracy to obtain several geometric points , , Indicates the sequence number of the geometric point, Represents the total number of geometric points;

[0019] Step S24: Start by looping and calculating the geometric points To geometry The shortest distance to the border, up to End the loop, then find the geometric point that meets the shortest distance value by comparing the obtained shortest distance value ;

[0020] Step S25: Get geometric points On the geometric surface Normal vector on , the positive direction of the normal vector points to the interior of the three-dimensional entity of the part model;

[0021] Step S26: Start by looping and calculating the geometric points Towards the geometric surface The projection distance, the projection direction is the normal vector , until End the loop, and then find the smallest non-zero projection distance value from all projection distance values. This distance value is the reference thickness dimension. .

[0022] In order to better implement the present invention, further, the comprehensive thickness size in step S3 The calculation steps are as follows:

[0023] Step S31: Use the geometric surface area calculated in step 2.2 , further calculate the surface area of ​​the part model , the calculation expression is: ;

[0024] Step S32: Determine the geometric surface Whether to include reference thickness dimension features;

[0025] Step S33: If the geometric surface If a reference thickness feature is included, the surface area is updated The expression is: ;

[0026] Step S34, repeat steps S32 to S33 until all geometric surfaces are All judgments are completed to obtain the final surface area ;

[0027] Step S35: Calculate part model Volume , and according to and , calculate the part model Comprehensive thickness dimensions The calculation formula is: .

[0028] In order to better implement the present invention, further, the geometric surface in step S32 The judgment rule of whether to include reference thickness dimension feature is: Get the geometric surface For all boundary lines, measure the shortest distance between any two boundary lines respectively. If there is a shortest distance between two boundary lines that is equal to the reference thickness dimension, If they are equal, Include reference thickness size features, otherwise, Reference thickness size features are not included.

[0029] In order to better implement the present invention, further, the thickness size in step S6 The calculation method is as follows:

[0030] Step S61: Fillet feature Get a geometric point on And the normal vector pointing to the interior of the three-dimensional solid at that point ;

[0031] Step S62: Start by looping and calculating the geometric points Towards the geometric surface The projection distance, the projection direction is the normal vector , until End the loop and find the smallest non-zero projection distance value among all projection distance values. This distance value is the fillet feature. Thickness .

[0032] In order to better realize the present invention, further, when checking the comprehensive thickness size With reference thickness dimension When the consistency , it is determined that the consistency requirements are not met; when checking the fillet feature Thickness With reference thickness dimension When the consistency , it is determined that the consistency requirement is not met; among them, The precision parameter for consistency checking.

[0033] In order to better realize the present invention, further, the .

[0034] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0035] (1) The present invention utilizes a significant difference between sheet metal parts and other types of parts: the thickness dimensions at any point on the surface of sheet metal parts are equal, and proposes a method for realizing rapid identification of sheet metal part models. By parsing, processing and converting the given part model data, the part geometric surface is discretized into a point set, and the thickness dimension features of each point on the surface are extracted or calculated. By judging whether the thickness dimensions of the parts are equal, the sheet metal part models are efficiently and accurately screened out from the aircraft design model, solving the problems of heavy workload, low efficiency and easy error in the current manual screening method. It can shorten the division of labor in aircraft manufacturing process and the production preparation cycle of related links, and can also provide more accurate input for sheet metal part process design.

[0036] (2) The present invention calculates a reliable reference thickness dimension on the part model as a benchmark, and realizes sheet metal part model recognition by checking the consistency of other thickness dimensions with the reference thickness dimension. It can provide accurate quantitative information and also reflect the specific parts of the part model that do not meet the thickness characteristics of sheet metal parts;

[0037] (3) The present invention proposes a calculation method for the comprehensive thickness dimension and fillet thickness dimension, which can make a quick judgment on whether the part model is a sheet metal part as a whole, while taking into account the local features and dimensions on the part model. Therefore, while ensuring accuracy, it effectively avoids performing a large number of thickness dimension feature calculations on the model, thereby improving calculation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 These are examples of parts tested in the specific embodiments of the present invention. DETAILED DESCRIPTION

[0039] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0040] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0041] Example 1:

[0042] This embodiment provides a method for rapidly identifying aircraft sheet metal part models based on thickness dimension features. The method realizes sheet metal part model identification by checking the consistency between the comprehensive thickness dimension of the part and the reference thickness dimension. The specific steps include:

[0043] Step S1: Batch read the part models to be identified according to the folder path set by the user ,in , Indicates the part model number, Indicates the total number of part models, set , set two sets with initial values ​​​​to be empty and , used to record non-sheet metal part models and sheet metal part models respectively;

[0044] Step S2: If , then calculate the part model Reference thickness dimensions ; Otherwise, execute step S9;

[0045] Step S3: For the part model to be identified , calculate the comprehensive thickness dimension of the part model ;

[0046] Step S4: Check the consistency between the comprehensive thickness dimension and the reference thickness dimension. If the consistency requirement is not met, the part model is judged to be If it is a non-sheet metal part, Add to non-sheet metal part model collection Then set , return to step S2;

[0047] Step S5: traverse the part model Round feature in , , Indicates the serial number of the fillet feature, Indicates the total number of round features; if , then go to step S8, otherwise set ;

[0048] Step S6: , calculate the fillet feature Thickness ; Otherwise, execute step S8;

[0049] Step S7: Check the consistency between the fillet thickness and the reference thickness. If the consistency is not satisfied, determine the part model. If it is a non-sheet metal part, Add to non-sheet metal part model collection and set , go to step S2, otherwise set , return to step S6;

[0050] Step S8: Determine the part model For sheet metal parts, Add to Sheet Metal Part Model Collection and set , go to step S2;

[0051] Step S9: Output non-sheet metal part model sets separately and sheet metal part model collections All models in .

[0052] Example 2:

[0053] This embodiment is further expanded on the basis of embodiment 1. The reference thickness size in step S2 is The calculation steps are as follows:

[0054] Step S21: traverse the part model The geometric surface in , , Indicates the geometric surface number, Indicates the total number of geometric faces;

[0055] Step S22: Start by looping and calculating each geometric face Area , until End the loop, and then find the geometric surface with the largest area by comparing the obtained area values ;

[0056] Step S23: Geometric surface Discretize according to the set accuracy to obtain several geometric points , , Indicates the sequence number of the geometric point, Represents the total number of geometric points;

[0057] Step S24: Start by looping and calculating the geometric points To geometry The shortest distance to the border, up to End the loop, then find the geometric point that meets the shortest distance value by comparing the obtained shortest distance value ;

[0058] Step S25: Get geometric points On the geometric surface Normal vector on , the positive direction of the normal vector points to the interior of the three-dimensional entity of the part model;

[0059] Step S26: Start by looping and calculating the geometric points Towards the geometric surface The projection distance, the projection direction is the normal vector , until End the loop, and then find the smallest non-zero projection distance value from all projection distance values. This distance value is the reference thickness dimension. .

[0060] The comprehensive thickness dimension in step S3 The calculation steps are as follows:

[0061] Step S31: Use the geometric surface area calculated in step 2.2 , further calculate the surface area of ​​the part model , the calculation expression is: ;

[0062] Step S32: Determine the geometric surface Whether to include reference thickness dimension features;

[0063] Step S33: If the geometric surface If a reference thickness feature is included, the surface area is updated , and the update expression is: ;

[0064] Step S34, repeat steps S32 to S33 until all geometric surfaces are All judgments are completed to obtain the final surface area ;

[0065] Step S35: Calculate part model Volume , and according to and , calculate the part model Comprehensive thickness dimensions The calculation formula is: .

[0066] The geometric surface in step S32 The judgment rule of whether to include reference thickness dimension feature is: Get the geometric surface For all boundary lines, measure the shortest distance between any two boundary lines respectively. If there is a shortest distance between two boundary lines that is equal to the reference thickness dimension, If they are equal, Include reference thickness size features, otherwise, Reference thickness size features are not included.

[0067] The thickness dimension in step S6 The calculation method is as follows:

[0068] Step S61: Fillet feature Get a geometric point on And the normal vector pointing to the interior of the three-dimensional solid at that point ;

[0069] Step S62: Start by looping and calculating the geometric points Towards the geometric surface The projection distance, the projection direction is the normal vector , until End the loop and find the smallest non-zero projection distance value among all projection distance values. This distance value is the fillet feature. Thickness .

[0070] Set the accuracy parameters for consistency checking When checking the consistency between the comprehensive thickness dimension and the reference thickness dimension, if , it is judged that the consistency requirement is not met; when checking the consistency of the fillet thickness dimension and the reference thickness dimension, if , it is determined that the consistency requirement is not met. Preferably, .

[0071] This embodiment develops a computer program based on the above steps 1 to 9. Figure 1 The eight representative part models to be identified are used as input to verify the technical solution of the present invention. Figure 1 Parts 1 to 4 are sheet metal parts, and parts 5 to 8 are non-sheet metal parts. The identification results are used as a comparison basis for the program calculation results. From an overall perspective, the present invention accurately identifies all sheet metal part models from the 8 part models to be identified, with an accuracy rate of 100%.

[0072] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification or equivalent change made to the above embodiment based on the technical essence of the present invention falls within the scope of protection of the present invention.

Claims

1. A method for rapid identification of aircraft sheet metal parts models based on thickness dimensional features, characterized in that: The sheet metal part model is identified by checking the consistency between the comprehensive thickness dimension of the part and the reference thickness dimension. The specific steps include: Step S1: Batch read the part models to be identified according to the folder path set by the user P i ,in i =1,2,…, N , i Indicates the part model number, N Indicates the total number of part models, set i =1, set two sets with initial values ​​as empty G and Y , used to record non-sheet metal part models and sheet metal part models respectively; Step S2: If i≤N , then calculate the part model P i Reference thickness dimensions h 0; otherwise, go to step S9; Step S3: For the part model to be identified P i , calculate the comprehensive thickness dimension of the part model h 1; Step S4: Check the consistency between the comprehensive thickness dimension and the reference thickness dimension. If the consistency requirement is not met, the part model is judged to be P i If it is a non-sheet metal part, P i Add to non-sheet metal part model collection G Then set i = i +1, return to step S2; Step S5: traverse the part model P i Round feature in C q , q =1,2,…, U , q Indicates the serial number of the fillet feature, U Indicates the total number of round features; if U =0, go to step S8, otherwise set q =1; Step S6: q≤U , calculate the fillet feature C q Thickness dimension γ q ; Otherwise, execute step S8; Step S7: Check the consistency between the fillet thickness and the reference thickness. If the consistency is not satisfied, determine the part model. P i If it is a non-sheet metal part, P i Add to non-sheet metal part model collection G and set i = i +1, go to step S2, otherwise set q = q +1, return to step S6; Step S8: Determine the part model P i For sheet metal parts, P i Add to Sheet Metal Part Model Collection Y and set i = i +1, go to step S2; Step S9: Output non-sheet metal part model sets separately G and sheet metal part model collections Y All models in; The thickness dimension γ in step S6 q The calculation method is as follows: Step S61: Fillet feature C q Get a geometric point on Pnt q And the normal vector Ω pointing to the interior of the three-dimensional solid at that point q ; Step S62: j =1 starts, loop calculation of geometric points Pnt q Towards the geometric surface F j The projection distance, the projection direction is the normal vector Ω q , until j = M End the loop and find the smallest non-zero projection distance value among all projection distance values. This distance value is the fillet feature. C q Thickness γ q .

2. The method for rapid identification of aircraft sheet metal parts models based on thickness dimensional features according to claim 1 is characterized in that: The reference thickness dimension in step S2 h The calculation steps for 0 are as follows: Step S21, traverse the part model P i The geometric surface in F j , j =1,2,…, M , j Indicates the geometric surface number, M Indicates the total number of geometric faces; Step S22: j =1, loop to calculate each geometric surface F j Area A j , until j = M End the loop, and then find the geometric surface with the largest area by comparing the obtained area values Fmax ; Step S23: Geometric surface Fmax Discretize according to the set accuracy to obtain several geometric points Pnt k , k =1,2,…, n , k Indicates the sequence number of the geometric point, n Represents the total number of geometric points; Step S24: k =1 starts, loop calculation of geometric points Pnt k To geometry Fmax The shortest distance to the border, up to k = n End the loop, then find the geometric point that meets the shortest distance value by comparing the obtained shortest distance value Pmax ; Step S25: Get geometric points Pmax On the geometric surface Fmax The normal vector Ω on the part model points to the interior of the three-dimensional entity; Step S26: j =1 starts, loop calculation of geometric points Pmax Towards the geometric surface F j The projection distance, the projection direction is the normal vector Ω, until j = M End the loop, and then find the smallest non-zero projection distance value from all projection distance values. This distance value is the reference thickness dimension. h 0.

3. The method for rapid identification of aircraft sheet metal parts models based on thickness dimensional features according to claim 2 is characterized in that: The comprehensive thickness dimension in step S3 h The calculation steps of 1 are as follows: Step S31: Use the geometric surface area calculated in step 2.2 A j , further calculate the surface area of ​​the part model S , the calculation expression is: ; Step S32: Determine the geometric surface F j Whether to include reference thickness dimension features; Step S33: If the geometric surface F j If a reference thickness feature is included, the surface area is updated S The expression is: S = S - F j ; Step S34, repeat steps S32 to S33 until all geometric surfaces are F j All judgments are completed to obtain the final surface area S ; Step S35: Calculate part model P i Volume V , and according to S and V , calculate the part model P i Comprehensive thickness dimensions h 1; the calculation formula is: .

4. The method for rapid identification of aircraft sheet metal parts models based on thickness dimensional features according to claim 3 is characterized in that: The geometric surface in step S32 F j The judgment rule of whether to include reference thickness dimension feature is: Get the geometric surface F j For all boundary lines, measure the shortest distance between any two boundary lines respectively. If there is a shortest distance between two boundary lines that is equal to the reference thickness dimension, h 0 is equal, then F j Include reference thickness size features, otherwise, F j Reference thickness size features are not included.

5. A method for rapid identification of aircraft sheet metal parts models based on thickness dimensional features according to any one of claims 1 to 4, characterized in that: When checking the comprehensive thickness dimension h 1 and reference thickness dimensions h 0 consistency, if , it is determined that the consistency requirements are not met; when checking the fillet feature C q Thickness γ q With reference thickness dimension h 0 consistency, if , it is determined that the consistency requirements are not met; among which: ε A precision constant for consistency checking.

6. The method for rapid identification of aircraft sheet metal parts models based on thickness dimensional features according to claim 5 is characterized in that: described ε =10 -3 mm .

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