Door structure modeling method and modeling system

Abstract

This invention discloses a method and system for modeling vehicle door structures, relating to the field of automotive design technology. The method includes: determining the large glass surface based on the glass boundary of the door window frame; calling a library of standard door cross-sections with predefined standard cross-sectional references based on the door structure; determining design cross-sectional references for each standard cross-section based on the door structure design parameters; adjusting the standard cross-sectional references to the design cross-sectional references to determine the design position of each cross-section; and generating a door structure model based on all determined cross-sectional positions. This invention achieves rapid and standardized modeling of vehicle door structures through parametric and automated cross-sectional reference alignment and positioning, reducing repetitive manual work, improving design efficiency and consistency, and enabling early verification and optimization of key designs such as hinge arrangement. The system includes corresponding functional modules to implement the method.

Description

Technical Field

[0001] This invention relates to the field of automotive design technology, specifically to a method and system for modeling vehicle door structures. Background Technology

[0002] The rapid development of China's economy has led to short sales cycles and rapid product updates for domestically produced automobiles. However, current automotive project development cycles are long, and data modeling workloads are substantial. In the early stages of a project, door structure modeling and development require significant manpower and resources for data arrangement, setup, and verification. During the door product development phase, before the styling is finalized, there is considerable uncertainty. Furthermore, there are often two or even three styling versions being developed simultaneously, which exponentially increases the workload of product structure design. With the same manpower, this results in extended work hours, and product structure designers are also performing meaningless, tedious, and repetitive tasks.

[0003] To address this technical issue, a Chinese invention patent with publication number "CN111539066B" titled "A Method for Parametric Integrated Design of Automobile Door Covers" describes a door cover design method. This method includes the following steps: CAS (Design for Assembling and Constraints) is published, whereby the CAS includes basic glass surfaces, seams, and distinctive A-pillars, B-pillars, and C-pillars; parametric layout modules are used with a parametric section library, parts library, and reuse library to complete the drawing of standard sections, modeling of part data, and modeling of assembly data for the door cover. This design method integrates the door cover data layout, construction, and verification into parametric modules that can be directly called during project development. By changing relevant parameters, the required data and positions can be obtained, efficiently achieving the desired purpose, reducing data construction time, and shortening the project development cycle.

[0004] However, this existing technical method still requires manual searching and calling of cross sections from the cross section library, and repeatedly iterating and adjusting various parameters such as the reference axis, reference point and reference plane of the cross section to match the design expectations. The process is cumbersome and the efficiency needs to be improved. Summary of the Invention

[0005] The purpose of this application is to address the shortcomings of the aforementioned background technology and provide a method and system for modeling vehicle door structures.

[0006] The technical solution of this application is: a method for modeling a car door structure, including: The large surface area of ​​the glass is determined based on the glass boundary of the car door and window frame. Based on the door structure, call the corresponding standard door section library; Based on the door structure design parameters, determine the design section reference for each section, adjust the standard section reference in the standard section library to the design section reference, and determine the design section position. The initial position of the door hinge is determined according to the design specifications. The door hinge at the initial position is then verified and analyzed to determine whether it meets the design requirements. If it does not meet the design requirements, the door hinge position is readjusted until it meets the design requirements, and the hinge installation section position is determined. Based on all the determined design section locations, generate the door structure model.

[0007] According to the vehicle door structure modeling method provided in this application, the method for determining the large surface of the glass based on the glass boundary of the vehicle door window frame includes: selecting at least three points in the front boundary of the glass, at least three points in the rear boundary, and the arc curve formed by the intersection of the water section and the glass surface from the glass design parameters of the vehicle door window frame, and generating a hyperbolic glass surface using a hyperbolic glass surface fitting method.

[0008] According to the door structure modeling method provided in this application, the method of calling the corresponding door standard section library based on the door structure includes: calling the section at the upper hinge, the section at the lower hinge, the section at the middle limiter, the section at the top of the door window frame, the section at the B-pillar of the door window frame, the section at the door lock, the section at the door sill, the section at the door window sill, and the section at the door anti-collision beam from the door standard section library based on the door structure.

[0009] According to the door structure modeling method provided in this application, the method for determining the design section reference of each section based on the door structure design parameters includes: selecting the midpoint of the upper boundary of the glass of the door window frame along the X direction as the first reference point, obtaining the first reference surface based on the first reference point, obtaining the first intersection line between the first reference surface and the glass surface, and taking the tangent line of the first intersection line at the first reference point as the first reference line; using the first reference point, the first reference surface and the first reference line as the design section reference of the section on the upper part of the door window frame.

[0010] According to the door structure modeling method provided in this application, the method for determining the design section reference of each section based on the door structure design parameters includes: stretching the facade of the B-pillar window frame trim panel in the Y direction to obtain a second intersection line with the glass surface; taking the midpoint of the second intersection line as a second reference point; taking the normal plane of the second intersection line as a second reference plane based on the second reference point; obtaining a third intersection line between the second reference plane and the glass surface; taking the tangent line of the third intersection line at the second reference point as a second reference line; and using the second reference point, the second reference plane, and the second reference line as the design section reference of the section at the B-pillar of the door window frame.

[0011] According to the door structure modeling method provided in this application, the method for determining the design section reference of each section based on the door structure design parameters includes: taking the spatial coordinate point of door lock engagement as the third reference point, taking the normal plane passing through the third reference point and perpendicular to the door hinge axis as the third reference plane, and taking the tangent of the arc rotating around the door hinge axis passing through the third reference point as the third reference line; and taking the third reference point, the third reference plane and the third reference line as the design section reference of the section at the door lock.

[0012] According to the door structure modeling method provided in this application, the method for determining the design section reference of each section based on the door structure design parameters includes: taking the midpoint of the stop at the door threshold as the fourth reference point, taking the X-direction plane passing through the fourth reference point as the fourth reference plane, and taking the Z-direction line passing through the fourth reference point as the fourth reference line; and using the fourth reference point, the fourth reference plane, and the fourth reference line as the design section reference of the section at the threshold.

[0013] According to the door structure modeling method provided in this application, the method for determining the design section reference of each section based on the door structure design parameters includes: taking the intersection line of the Y-direction extension plane of the water cut of the door window sill and the glass surface as the fourth intersection line, taking the midpoint of the fourth intersection line as the fifth reference point, taking the normal plane of the fourth intersection line based on the fifth reference point as the fifth reference plane, and taking the tangent line of the fourth intersection line at the fifth reference point on the fifth reference plane as the fifth reference line; and using the fifth reference point, the fifth reference plane and the fifth reference line as the design section reference of the section at the door window sill.

[0014] According to the door structure modeling method provided in this application, the method for determining the design section reference of each section based on the door structure design parameters includes: obtaining the trend line of the door anti-collision beam based on the design parameters of the door anti-collision beam; taking the intersection of the trend line extending along the Y direction and the outer panel of the door as the fifth intersection line; taking the midpoint of the fifth intersection line as the sixth reference point; taking the normal plane of the fifth intersection line based on the sixth reference point as the sixth reference plane; and taking the normal line perpendicular to the outer panel of the door based on the sixth reference point as the sixth reference line; and using the sixth reference point, the sixth reference plane, and the sixth reference line as the design section reference of the section at the door anti-collision beam.

[0015] According to the door structure modeling method provided in this application, the method for determining the design section reference of each section based on the door structure design parameters includes: taking the midpoint of the hinge axis of the upper hinge as the seventh reference point, taking the normal plane that passes through the seventh reference point and is perpendicular to the axis of the upper hinge as the seventh reference plane, taking the line that extends along the X direction through the seventh reference point as the seventh reference line, and taking the seventh reference point, the seventh reference plane and the seventh reference line as the design section reference of the section at the upper hinge; The midpoint of the hinge axis of the lower hinge is the eighth reference point. The normal plane that passes through the eighth reference point and is perpendicular to the axis of the lower hinge is the eighth reference plane. The line that extends along the X direction through the eighth reference point is the eighth reference line. The eighth reference point, the eighth reference plane and the eighth reference line are used as the design section references for the section at the lower hinge. The midpoint of the pivot of the middle limiter is taken as the ninth reference point, the normal plane that passes through the ninth reference point and is perpendicular to the axis of the pivot of the middle limiter is taken as the ninth reference plane, and the line that extends along the X direction through the ninth reference point is taken as the ninth reference line. The ninth reference point, the ninth reference plane and the ninth reference line are used as the design section reference for the section at the middle limiter.

[0016] According to the door structure modeling method provided in this application, the method for verifying and analyzing the door hinge at the initial position includes: determining the safety distance of the door outer panel motion envelope at the door hinge section; determining the rear boundary points of the door outer panel at the upper hinge section, the lower hinge section, and the middle limiter section; connecting the three rear boundary points to form the rear boundary line of the door outer panel; taking the intersection line between the mounting surface of the door hinge on the body side and the outer surface of the preliminary body styling surface after the structure is rotated counterclockwise to set the opening degree as the front boundary line; the area between the front boundary line and the rear boundary line as the seam area; if the seam area exists, it is determined that the door hinge at the current initial position meets the design requirements; otherwise, it does not meet the design requirements; if it does not meet the design requirements, the door hinge position, the door hinge tilt angle parameter, or the outer surface of the preliminary body styling surface are adjusted until the seam area exists.

[0017] According to the door structure modeling method provided in this application, the method for generating a door structure model based on all determined design cross-sectional positions includes: constructing a door opening sealing surface reference based on the determined cross-sections at the upper hinge, lower hinge, middle limiter, upper door window frame, B-pillar of door window frame, door lock, and sill; and creating the large surface of the inner door panel based on the door opening sealing surface reference using sweeping and bridging methods. The door frame line is constructed based on the determined cross-sections at the top of the door window frame, the B-pillar of the door window frame, and the sill of the door; the side of the inner door panel is made based on the door frame line using sweeping and bridging methods. Based on the determined cross-sections at the upper hinge, lower hinge, middle limiter, upper part of the door window frame, B-pillar of the door window frame, door lock, and sill, the installation side lines required for the installation of the door sealing strip are obtained; the installation surface of the door sealing strip is made by sweeping and bridging based on the installation side lines. Based on the first reference point in the cross section of the determined door and window frame and the thickness of the edging material, the inner door panel edging surface is made by sweeping and bridging. Based on the determined cross-sections at the upper hinge, lower hinge, middle limiter, upper door window frame, B-pillar of door window frame, door lock, and sill, construct the center elevation line of the inner door panel; based on the center elevation line of the inner door panel, create the inner door panel elevation by sweeping and bridging. The inner door panel is formed by cutting the large surface, side surface, sealing strip mounting surface, edging surface, and vertical surface of the inner door panel.

[0018] According to the vehicle door structure modeling method provided in this application, the method for generating a vehicle door structure model based on all determined design section positions includes: taking the design parameters of the vehicle door window regulator as input, generating the mounting surface and mounting hole positions of the vehicle door window regulator, and generating a data model of the vehicle door window regulator based on the mounting surface and mounting hole positions; Extract the window frame structure lines from the cross-sections at the lower hinge, the upper part of the door window frame, and the door window sill. Based on the window frame structure lines and taking the inner panel of the door as the reference, fabricate the door window frame reinforcement plate by sweeping and bridging. Extract the hinge structure lines from the cross-sections of the upper and lower hinges, and fabricate the door hinge reinforcement plate based on the hinge structure lines and the mating area of ​​the inner door panel using sweeping and bridging methods. Extract the structural line of the middle limiter from the cross section at the middle limiter, and based on the structural line of the middle limiter and taking the mating part of the inner door panel as the reference, fabricate the middle limiter reinforcement plate by sweeping and bridging. Extract the door lock structure line from the cross-section of the door lock, and based on the door lock structure line and the mating area of ​​the inner door panel, fabricate the door lock reinforcement plate by sweeping and bridging. Extract the window sill structure line of the cross section at the car door window sill, and based on the window sill structure line and the mating part of the car door inner panel, make the window sill reinforcement plate by sweeping and bridging. Extract the sill structure line of the sill section, and based on the sill structure line and the mating part of the inner door panel, make the sill reinforcement plate by sweeping and bridging. Extract the structural line of the door anti-collision beam from the cross-section of the door anti-collision beam, and based on the structural line of the door anti-collision beam and the mating area of ​​the inner door panel, fabricate the door anti-collision beam reinforcement plate by sweeping and bridging.

[0019] According to the door structure modeling method provided in this application, the method for generating a door structure model based on all determined design section positions includes: extracting the door outer panel structure line where the anti-scratch strip is installed at the door sill; and fabricating the door outer panel by cutting and connecting the structure line at the anti-scratch strip and the preliminary shape surface of the door outer panel.

[0020] This application also provides a vehicle door structure modeling system for implementing the vehicle door structure modeling method described in any of the above claims, the system comprising: A large glass surface construction module is used to determine the large glass surface based on the glass boundary of the car door window frame. A standard section library calling module is used to call the corresponding standard section library of the door according to the door structure. The design section reference determination module is used to determine the design section reference for each section based on the door structure design parameters. The modification and adjustment module is used to adjust the standard section reference in the standard section library to the design section reference and determine the design section position. The verification module is used to determine the initial position of the door hinge according to the design specifications, perform verification analysis on the door hinge at the initial position, and determine whether the door hinge at the initial position meets the design requirements. If it does not meet the design requirements, the door hinge position is readjusted until it meets the design requirements, and the hinge installation section position is determined. The door inner panel construction module is used to output the door inner panel according to the determined design cross-sectional position, and to construct the mounting components and reinforcements on the door inner panel based on the design parameters and the determined design cross-sectional position; A door outer panel construction module is used to output the door outer panel according to the determined design cross-sectional position.

[0021] The beneficial effects of this application include: A standardized and parameterized automated modeling process has been constructed: through the logical closed loop of "determining the glass surface - calling the standard section library - parameterizing the alignment benchmark - verifying and optimizing the hinge position - generating the complete model", the traditional design mode that relies on human experience and serial trial and error is transformed into an efficient and reusable digital process, which reduces repetitive labor from the root and greatly improves modeling efficiency and design consistency. Intelligent positioning and adaptation of key structural sections have been achieved: For each key functional area of ​​the car door (such as window frame, hinge, door lock, etc.), rules are defined to automatically calculate unique point, line, and surface design benchmarks based on geometric parameters (such as glass surface, hard point coordinates, etc.). These rules eliminate the subjective arbitrariness of manual placement and can intelligently adjust the pre-stored standard sections to the design position, ensuring the functional rationality and accuracy of the section position, which is the core of achieving rapid modeling. An early automated verification and optimization mechanism is embedded: the motion interference check of the door hinge arrangement is transformed into a static geometric judgment of the "seam region" and integrated into the modeling process; this method can automatically and quickly verify and optimize the hinge scheme in the early stage of design, avoid major rework in the later stage, significantly shorten the development cycle, and reduce the cost of physical verification. It achieves fully parametric associative design and knowledge solidification: Based on the located cross-section, the inner / outer panels of the car door and various reinforcements are automatically generated through rule-driven surface modeling methods (such as sweeping and bridging). All components are fully associated with the input parameters and cross-sectional references. Any change in design parameters can be automatically transmitted to the entire model, supporting the rapid synchronous development of multiple styling schemes, and solidifying mature design experience into reusable templates and rules. Attached Figure Description

[0022] Figure 1 : A schematic diagram of the door structure modeling method of this application; Figure 2 : A schematic diagram of the standard cross-section library of this application; Figure 3 : A schematic diagram of the cross-sectional reference structure at the top of the car door window frame in this application; Figure 4 : A schematic diagram of the cross-sectional reference construction at the B-pillar of the vehicle door window frame in this application; Figure 5 : Schematic diagram of the cross-sectional reference at the B-pillar of the car door window frame in this application (schematic diagram of the third intersection line construction); Figure 6 : Schematic diagram of the cross-sectional reference construction at the door lock in this application; Figure 7 : A schematic diagram of the cross-sectional benchmark construction at the threshold of this application; Figure 8 : A schematic diagram of the cross-sectional reference construction at the car door window sill in this application; Figure 9 : A schematic diagram of the cross-sectional reference structure at the door anti-collision beam in this application; Figure 10 : A schematic diagram of the cross-sectional reference construction at the upper hinge of this application; Figure 11 : A schematic diagram of the cross-sectional reference construction at the lower hinge of this application; Figure 12 : A schematic diagram of the cross-sectional reference construction at the middle limiter in this application; Figure 13 : A schematic diagram illustrating the construction of the front and rear boundary lines of this application; Figure 14 : A schematic diagram of the construction of the door opening sealing surface reference in this application; Figure 15 This application includes a schematic diagram of the door frame line construction in the vehicle door. Figure 16 This application provides a schematic diagram of the door sealing strip mounting surface construction. Figure 17 : A schematic diagram of the construction of the inner door panel edge banding surface in this application; Figure 18 : A schematic diagram of the elevation construction of the inner panel of the vehicle door in this application; Figure 19 This application provides a schematic diagram of the generation of the inner door panel. Figure 20 This application includes a manufacturing drawing of the door and window frame reinforcement plate. Figure 21 : The manufacturing drawing of the outer door panel of this application. Detailed Implementation

[0023] The embodiments of this application are described in detail below, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0024] In the description of this application, it should be understood that the terms "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0025] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0026] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0027] This application relates to a door structure modeling method. This method revolutionarily shortens the development cycle, reducing the traditional months-long manual design cycle to days or even hours, enabling rapid response to styling changes. It significantly reduces repetitive manual labor, allowing engineers to focus on innovation and optimization. Simultaneously, the standardized process ensures design quality from the outset. It can generate door structures for multiple styling schemes, transforming the seemingly impossible task into a simple matter of "a few clicks," significantly reducing the marginal cost of concurrent development. The fully parameterized and rule-based digital process constructed by this door structure modeling method lays the foundation for subsequent integration with artificial intelligence for automated optimization and the use of big data to mine optimal cross-sectional parameters. Furthermore, this modeling method can be extended to the modeling design of other assemblies, directly analogous to and applicable to the design of other body panels such as the hood and trunk lid, and even the body-in-white frame, demonstrating broad application prospects.

[0028] Specifically, such as Figure 1 As shown, the door structure modeling method of this application can be performed according to the following steps: S1: Determine the large glass surface based on the glass boundary of the car door and window frame; S2: Based on the door structure (such as front door, rear door, frameless door, etc.), call the preset corresponding door standard section library; S3: Based on the door structure design parameters (such as styling surfaces, hard point coordinates, regulatory requirements, etc.), determine the design section reference (one reference point, one reference surface, and one reference line) for each section to be called; then, adjust the predefined standard section reference on the corresponding standard section in the standard section library to the design section reference through coordinate transformation (such as translation and rotation), thereby determining the design section position of the standard section in the vehicle coordinate system; S4: Adjust the door hinge position initially according to the design specifications (such as opening requirements and minimum clearance) to generate the hinge section at the initial position; perform kinematic verification analysis on the initial position to determine whether it meets the design requirements; if it does not meet the requirements, readjust the hinge position (or its tilt angle) and update the corresponding section position until the verification is passed, and finally determine the hinge installation section position. S5: Based on all the determined design section positions, output a complete door inner panel surface model through surface modeling methods (such as sweeping, bridging, and trimming); at the same time, based on the relevant design parameters and these section positions, automatically build and assemble the mounting components (such as window regulators) and various reinforcements (such as hinge reinforcement plates and anti-collision beam reinforcement plates) on the door inner panel. S6: Based on the determined design section location (especially the section at the door sill) and the outer surface of the vehicle body, output the curved surface model of the outer door panel.

[0029] 2. Principle Description The modeling method of this application deconstructs the complex process of modeling a three-dimensional solid body of a car door into two levels: a two-dimensional cross-section for reference positioning and a three-dimensional surface derived from the cross-section. First, standard cross-sections are quickly and accurately placed at specific positions on the new car model using parametric references to form the reference skeleton of the car door structure. Then, using these positioned cross-sections as contour lines and guide lines, the surface generation function of CAD software is used to automatically construct the three-dimensional model. Among them, the hinge verification step is a key verification test process to ensure the feasibility of the car door movement.

[0030] The door structure modeling method proposed in this application transforms disordered manual design into ordered automated steps, avoiding omissions and repetitions, and improving modeling efficiency by more than 70%. Integrated hinge verification enables major design defects to be discovered early in the data phase, avoiding major modifications in the physical prototype phase, and is expected to shorten the development cycle by 2-3 weeks. Once the design parameters are determined, the model can be automatically generated, allowing one engineer to be responsible for the preliminary design of door structures for multiple styling schemes simultaneously, and the human resource requirements do not increase linearly with the number of projects.

[0031] In some embodiments of this application, this embodiment optimizes the above-mentioned step S1. Specifically, from the design parameters of the car door window frame glass, at least three points on the front boundary of the glass (e.g., upper, middle, and lower position points), at least three points on the rear boundary of the glass, and a segment of arc curve formed by the intersection of the water section (or window frame guide surface) and the theoretical glass surface are extracted. Using these boundary elements as constraints, a smooth and continuous hyperbolic surface, i.e., the large glass surface, is generated by using a hyperbolic surface fitting algorithm (such as NURBS surface fitting) in computer graphics.

[0032] Automotive side window glass is usually a complex hyperbolic surface. In this embodiment, the key boundary information that is limited and easily obtained from the modeling data is used to accurately reconstruct the entire surface through mathematical fitting. The front and rear boundary points control the curvature change of the glass in the vehicle's front-to-back direction (X direction), and the water tangent line controls the curvature trend of the glass in the vertical direction (Z direction), together uniquely determining a glass surface that meets the engineering requirements.

[0033] The glass surface construction method in this embodiment uses a small number of key points / lines to accurately define complex curved surfaces, avoiding the errors and time consumption of manual line drawing and modeling, and generating extremely fast (second-level) glass surfaces. The generated glass surfaces are completely related to the input boundary points and water section parameters. When the shape adjustment causes these inputs to change, the glass surfaces can be automatically updated with one click, which greatly facilitates multiple rounds of shape iteration.

[0034] In other embodiments of this application, step S2 described above has been optimized. Specifically, this embodiment specifically illustrates the composition and retrieval of the standard cross-section library. The pre-set standard cross-section library for car doors includes cross-section templates for the following nine key locations: upper hinge cross-section, lower hinge cross-section, middle limiter cross-section, upper door window frame cross-section, B-pillar cross-section of door window frame, door lock cross-section, sill cross-section, door window sill cross-section, and door anti-collision beam cross-section. When an engineer starts modeling a new car door, the system automatically retrieves these nine standard cross-sections from the library based on the selected door structure type, as templates for subsequent design.

[0035] For example, such as Figure 2 As shown, taking a front door with a window frame as an example, the standard cross-section library includes: cross-section a at the upper hinge, cross-section b at the lower hinge, cross-section c at the middle limiter, cross-section d at the top of the door window frame, cross-section e at the B-pillar of the door window frame, cross-section f at the door lock, cross-section g at the door sill, cross-section h at the door window sill, and cross-section i at the door anti-collision beam.

[0036] By modularly decomposing the car door into these nine key areas, and pre-setting a standard cross-section for each area that has been verified by multiple car models and includes the best cross-sectional shape, material thickness, and overlap relationship; during modeling, these templates are directly called for adaptive adjustments, rather than creating from scratch, which can effectively reduce the workload of modeling.

[0037] During the actual modeling process, select the "Door Type" (e.g., "Four-Door Sedan - Front Door - Framed") in the project management interface; the system background will automatically match and load the nine standard cross-section 2D drawings (or 3D contours) corresponding to this type from the standard cross-section database, and load them into the current working environment in an unpositioned state.

[0038] This embodiment solidifies optimized design experience into standard cross-sections, ensuring that any new project can start from a high starting point, significantly improving the baseline and consistency of design quality; by replacing drawing with calling, the design work can immediately enter the substantive modeling stage after the project starts, saving about 80% of the cross-section drawing time.

[0039] In a further embodiment of this application, step S3 described above is optimized. Specifically, this embodiment details how to determine the specific design benchmark for each standard cross-section under the current vehicle model; these benchmarks are all obtained through geometric calculations based on existing design parameters. Cross-sectional reference at the top of the car door and window frame (e.g.) Figure 2 As shown in d): Figure 3As shown, the main surface of the glass has been determined at this point. The upper boundary of the main surface of the glass is located at the top of the door and window frame. The midpoint of the upper boundary of the glass in the X direction is taken as the first reference point P1. The normal plane through the first reference point P1 is taken as the first reference plane N1. The line of intersection with the glass surface is taken as the first intersection line L1. The tangent of the first intersection line L1 at the first reference point P1 is taken as the first reference line T1. The design cross-sectional reference of the section at the top of the door and window frame is (P1, N1, T1). Cross-sectional reference at the B-pillar of the car door window frame (e.g.) Figure 2 e): as shown Figure 4 As shown, the B-pillar window frame decorative panel (glass side) facade is stretched in the Y direction to intersect with the glass surface to obtain the second intersection line L2. The midpoint of the second intersection line L2 is taken as the second reference point P2. The normal plane of the second intersection line L2 is drawn through the second reference point P2 as the second reference plane N2. The intersection line of the second reference plane N2 and the glass surface is the third intersection line L3 (as shown). Figure 5 As shown), the tangent of the third intersection line L3 at the second reference point P2 is taken as the second reference line T2; the design cross-sectional reference of the section at the B-pillar of the car door window frame is (P2, N2, T2). Cross-sectional reference at the door lock (e.g.) Figure 2 f): as shown Figure 6 As shown, the latch / ring engagement point of the door lock is taken as the third reference point P3. A normal plane perpendicular to the door hinge axis or latch hinge axis is drawn through the third reference point P3 as the third reference plane N3. The tangent line of the arc rotating around the hinge axis through the third reference point P3 at the third reference point P3 is the third reference line T3. The design cross-sectional reference of the door lock section is (P3, N3, T3). Cross-sectional reference at the threshold (e.g.) Figure 2 g): as shown Figure 7 As shown, the center point of the sill stop section is taken as the fourth reference point P4, the XZ plane passing through the fourth reference point P4 (i.e. the X-direction plane of the whole vehicle) is taken as the fourth reference plane N4, and the Z-direction straight line passing through the fourth reference point P4 is taken as the fourth reference line T4; the design section reference of the sill section is (P4, N4, T4). Cross-sectional reference at the car door window sill (e.g.) Figure 2 h): as shown Figure 8 As shown, the intersection of the water-tangential Y-direction extension surface and the glass surface is taken as the fourth phase intersection line L4. The midpoint of the fourth phase intersection line L4 is taken as the fifth reference point P5. The normal surface of the fourth phase intersection line L4 through the fifth reference point P5 is taken as the fifth reference surface N5. The tangent line of the fourth phase intersection line L4 at the fifth reference point P5 and located within the fifth reference surface N5 is taken as the fifth reference line T5. The design cross-sectional reference of the door window sill section is (P5, N5, T5). Cross-sectional reference at the door anti-collision beam (e.g.) Figure 2 As shown in i): Figure 9As shown, a trend line is obtained based on the design direction of the anti-collision beam. Extending it in the Y direction intersects the outer panel A surface to obtain the fifth intersection line L5. The midpoint of the fifth intersection line L5 is taken as the sixth reference point P6. The normal plane of the fifth intersection line L5 through the sixth reference point P6 is the sixth reference plane N6. Based on the sixth reference point P6, a normal line perpendicular to the outer panel A surface is drawn as the sixth reference line T6. The design cross-sectional reference of the section at the door anti-collision beam is (P6, N6, T6). Section reference at hinge / limiter (e.g.) Figure 2 (as shown in a, b, c): Figure 10 As shown, the center point of the hinge axis is the seventh reference point P7, the plane perpendicular to the hinge axis through the seventh reference point P7 is the seventh reference plane N7, and the X-direction line through the seventh reference point P7 is the seventh reference line T7, which serves as the design section reference (P7, N7, T7) for the section at the upper hinge. like Figure 11 As shown, the center point of the lower hinge axis is the eighth reference point P8, the plane perpendicular to the hinge axis through the eighth reference point P8 is the eighth reference plane N8, and the X-direction line through the eighth reference point P8 is the eighth reference line T8, which serves as the design section reference (P8, N8, T8) for the section at the lower hinge. like Figure 12 As shown, the midpoint of the pivot of the middle limiter is taken as the ninth reference point P9, the plane passing through the ninth reference point P9 and perpendicular to the axis of the pivot of the middle limiter is taken as the ninth reference plane N9, and the X-direction line passing through the ninth reference point P9 is taken as the ninth reference line T9, which serve as the design section reference (P9, N9, T9) for the section at the middle limiter.

[0040] In this embodiment, a mathematically calculable local coordinate system (i.e., reference point, surface, line) is defined for each functional section and is strongly correlated with the surrounding key geometric elements (glass, outer panel, structural components, motion axis). This local coordinate system uniquely determines the position and orientation of the section in space, ensuring the functional rationality of the section position.

[0041] In actual operation, after defining the large glass surface and inputting key hard points (such as locking engagement points and hinge axes), the system automatically performs the above geometric calculations according to the preset rule scripts, and calculates the design datum for each of the nine sections.

[0042] The method for obtaining cross-section design standards in this embodiment avoids the arbitrariness of manually placing cross-sections by feel, achieving automated positioning with millimeter-level accuracy, and the positioning process only takes a few seconds. The definition logic of each benchmark deeply reflects the functional requirements of the cross-section (such as sealing, movement, and load-bearing), so that the cross-section located by it naturally meets the functional requirements, reducing the need for structural adjustments to meet the functions later. This is the key link in the parameterization of the entire method. Any change in input parameters (such as glass surface, hard point coordinates) will automatically trigger the recalculation of benchmarks, thereby providing a driving force for the linkage update of the entire model.

[0043] In a preferred embodiment of this application, step S4 described above has been optimized, and the specific steps are as follows: S41. Using the span of the upper and lower hinges, the inward and outward tilt angles of the hinge shaft, the forward and backward tilt angles, and the CAS surface of the shape as input parameters, and at the same time initially determining the position of the upper and lower hinges (e.g., arranging the upper and lower hinges within the CAS of the shape, with the outer contour of the upper and lower hinges 20mm away from the outer plate, and the span of the upper and lower hinges 350mm), the initial positions of the upper and lower hinges can be obtained. The position of the middle limiter can be adjusted in the Z direction between the two. Based on the current positions of the upper and lower hinges and the middle limiter, calculate the motion envelope of the outer edge of the door during the opening process, and according to the safety distance requirement (the distance between the motion envelope of the outer edge of the door and the fender, such as 2.5mm), offset inward to obtain a safety envelope line. S42. Find the intersection points of the safety envelope and the theoretical outline of the outer panel of the door in the cross-sections at the upper and lower hinges and the middle limiter, respectively, and use them as the three rear boundary points. S43. Connect these three back boundary points to form a space curve, which serves as the back boundary line, such as... Figure 13 As shown; S44. Rotate the door hinge mounting surface and surrounding structures on the side of the vehicle body counterclockwise around the hinge axis to set the opening degree (e.g., 69°). The intersection line between this rotation and the outer surface of the preliminary side profile of the vehicle body is used as the front boundary line. Figure 13 As shown; S45. Determine whether there is a continuous gap area (i.e., gap region) between the front boundary line and the rear boundary line on the projection perpendicular to the door opening and closing plane. If it exists, it means that there is sufficient gap between the door and the outer body during the entire opening process, and the verification is passed. If it does not exist (i.e. the two lines intersect or the gap is negative), the verification fails. Adjust the position of the upper and lower hinges, the tilt angle parameters, or the outer CAS surface until a gap region exists.

[0044] If there is a seam area, the boundary line is moved forward by 0.1mm along the X direction to form the seam boundary, and the arrangement positions of the cross-sections at the upper hinge, lower hinge, and middle limiter are fixed to determine the design cross-section position.

[0045] This embodiment simplifies the complex dynamic three-dimensional motion interference check into a static two-dimensional projection area existence judgment; by calculating the gap between the outermost part (rear boundary line) of the door and the innermost part (front boundary line) of the vehicle body when the door is opened to the maximum angle, it is possible to predict whether there is no interference in the entire motion process.

[0046] This embodiment shortens the time required for dynamic simulation or physical verification from several hours or even days to automatic calculation within minutes and provides intuitive graphical results; it not only determines whether it is feasible, but also points out how to improve it, which greatly accelerates the optimization process and enables the hinge arrangement scheme to quickly converge to the optimal solution.

[0047] In some embodiments of this application, this embodiment details how to output the inner door panel based on a located cross-section; the method is a combined surface construction method: S51. Construct a reference for the sealing surface of the doorway: such as... Figure 14 As shown, a continuous boundary is generated by using the feature lines related to the vehicle body sealing in the cross-sections of the upper hinge, lower hinge, middle limiter, upper door window frame, B-pillar of door window frame, door lock, and sill. Guided by this boundary, the large surface of the inner door panel (mainly facing the interior of the passenger compartment) is generated by sweeping and bridging. S52. Construct the door frame line in the middle of the car door: (e.g.) Figure 15 As shown, the boundary lines of the upper section of the door window frame, the B-pillar section of the door window frame, and the inner side of the door window sill section are used as guides to generate the inner side of the door panel (the surface in contact with the glass and interior trim panels) through sweeping and bridging. S53. Construct side moldings for sealing strip installation: such as... Figure 16 As shown, based on the determined cross-sections at the upper hinge, lower hinge, middle limiter, upper door window frame, B-pillar of door window frame, door lock, and sill, the installation side lines required for installing the door seal strip are obtained. In fact, this involves extracting the boundary lines of the grooves or mating surfaces used for installing the seal strip on the above cross-sections. Based on this, the door seal strip installation surface is generated through sweeping and bridging. S54. Construct the border surface: as follows Figure 17 As shown, based on the first reference point P1 of the cross section on the window frame and considering the set edge material thickness (e.g., 6mm), an edge guide line is generated; by sweeping along the inner panel boundary, the inner panel edge surface of the door is generated. S55. Construct the center line of the inner panel: (e.g.) Figure 18As shown, extract the center elevation lines of the inner panel thickness on the cross-sections of the upper hinge, lower hinge, middle limiter, upper door window frame, B-pillar of door window frame, door lock, and sill; generate the inner panel elevation (the main vertical plane where the inner panel's skeleton and reinforcing ribs are located) by sweeping and bridging. S56. Finally, all generated surfaces (main surfaces, side surfaces, mounting surfaces, edge surfaces, and elevation surfaces) are trimmed and stitched together to form a complete, closed solid model of the car door inner panel, such as... Figure 19 As shown.

[0048] In this embodiment, the complex thin-shell component of the car door inner panel is regarded as being composed of several main functional curved surfaces. The precise cross-sectional shape and orientation of each functional curved surface at key positions are obtained through the positioned cross-section, and then the CAD sweep and bridging functions are used to automatically generate a smooth transition complete curved surface.

[0049] This embodiment avoids the quality defects (such as wrinkles and discontinuities) that may be caused by manual paving. The generated curved surface is of high quality and fully conforms to the engineering intent of the section definition. The generated edge and sealing surfaces directly meet the manufacturing and assembly process requirements, and the inner plate model is fully associated with all section references, realizing true full parametricization.

[0050] In a further embodiment of this application, the above-mentioned method for constructing mounting components and reinforcing parts on the inner panel of the car door is optimized. Specifically, for the model construction of the window regulator on the inner panel of the car door, the model design parameters of the window regulator are input, and the system automatically generates mounting boss surfaces and bolt hole positions in the preset area of ​​the large surface of the inner panel of the car door, and calls the standard parts library to generate a three-dimensional model of the regulator for assembly.

[0051] The construction of the reinforcement on the inner door panel includes: extracting the window frame structural lines from the cross-sections at the lower hinge, the upper part of the door window frame, and the window sill; and fabricating the door window frame reinforcement plate based on these structural lines and using the inner door panel mating area as a reference, through sweeping and bridging methods. Figure 20 As shown; The hinge structure lines are extracted from the cross-sections of the upper and lower hinges. Based on these hinge structure lines and using the mating area of ​​the inner door panel as a reference, a door hinge reinforcement plate is fabricated using sweeping and bridging methods. Extract the structural line of the middle limiter from the cross section at the middle limiter, and based on the structural line of the middle limiter and taking the mating part of the inner door panel as the reference, fabricate the middle limiter reinforcement plate by sweeping and bridging. Extract the door lock structure line from the cross-section of the door lock, and based on the door lock structure line and the mating area of ​​the inner door panel, fabricate the door lock reinforcement plate by sweeping and bridging. Extract the window sill structure line of the cross section at the car door window sill, and based on the window sill structure line and the mating part of the car door inner panel, make the window sill reinforcement plate by sweeping and bridging. Extract the sill structure line of the sill section, and based on the sill structure line and the mating part of the inner door panel, make the sill reinforcement plate by sweeping and bridging. Extract the structural line of the door anti-collision beam from the cross-section of the door anti-collision beam, and based on the structural line of the door anti-collision beam and the mating area of ​​the inner door panel, fabricate the door anti-collision beam reinforcement plate by sweeping and bridging.

[0052] For the seven reinforcing plates—window frame, hinges, limiters, door locks, window sills, door thresholds, and anti-collision beams—the method is standardized as follows: Extract the "structural line" describing the cross-sectional shape of the reinforcing plate from the corresponding pre-positioned design section; use this structural line as the cross-sectional profile, and the mating curved surface on the inner door panel (such as the main surface or elevation of the inner panel) as the sweeping guide surface or reference surface; through sweeping, stretching, and bridging operations, generate a solid reinforcing plate that fits well with the inner panel; the system automatically generates features such as welding edges, weight-reducing holes, and positioning holes for the reinforcing plate and the inner panel. The core function of the reinforcing plate is local reinforcement, and its position and shape must match the structure of the main section; therefore, directly extracting its cross-sectional profile from the corresponding design section is the most accurate and fastest method; by associating the model with the mating surface of the inner panel, assembly accuracy is ensured.

[0053] In actual operation, select the type to be generated in the reinforcement design menu (or select to generate all); the system automatically captures data from the corresponding cross-section and, with reference to the geometric data of the inner door panel, instantly generates solid models of all reinforcement plates and automatically assembles them into place.

[0054] In this embodiment, the door inner panel mounting structure generates all reinforcements with just one click, significantly reducing time consumption and ensuring complete consistency with the main section design; the reinforcement plates are fully associated with the inner panel and the section reference; when the inner panel changes due to shape adjustments, all reinforcement plates can automatically update accordingly, maintaining the correct assembly relationship, and the maintenance workload is close to zero.

[0055] In other embodiments of this application, the above-described method for outputting the outer door panel is optimized. Specifically, firstly, it is considered whether there is a rub strip on the outer door panel. If there is a rub strip, the structural line of the outer door panel where the rub strip is installed is extracted from the determined cross-section at the door sill. This spatial curve is used as an important cross-sectional guide line. Then, as... Figure 21As shown, combining the data of the A-side (outer surface of the body) and the door boundary lines (such as window frame boundaries and door opening boundaries), the styling surface is used as the main control surface, and the door outer panel structure line where the anti-scratch strip is installed at the door sill is used as the internal constraint. Through the cut and connect commands, a smooth door outer panel surface that meets the internal structural layout requirements is generated; finally, the edges of this surface are cut to form the final outer panel part.

[0056] If there are no anti-scratch strips, the outer door panel can be determined directly by the shape of the outer surface.

[0057] In this embodiment, surface A is used as the outer boundary, and a crash beam structural line is introduced as an internal engineering hard point constraint to ensure that the generated outer panel is aesthetically pleasing while having sufficient internal space to accommodate key components such as the crash beam.

[0058] During operation, after completing the construction of the inner panel and internal structure, click the command to generate the outer panel of the car door; the system reads the A-side data and the cross-sectional information of the anti-collision beam, automatically executes the surface construction algorithm, generates the outer panel surface, and automatically checks the gap between it and the edge surface of the inner panel.

[0059] The door outer panel generation method in this embodiment quickly found an outer panel solution that fits the shape and meets the engineering layout in an automated process, solving the problem of repeated adjustments in traditional design. Since the generation process takes into account the internal structure, it avoids the problem of insufficient internal space caused by an overly tight outer panel shape, thus improving manufacturability from the source.

[0060] In practice, let's take the development of a front door for a four-door sedan as an example: Input and initialization: Receive the A-side data from the styling department and the hard point files (including hinge axes, lock engagement points, etc.) provided by the general layout department; create a new project in the modeling system, selecting the front door and framed type; Generate base reference plane: The system automatically executes the above embodiment to generate the large glass plane based on the window frame boundary in plane A; Calling and locating the structural skeleton: The system automatically executes the above embodiment and calls nine standard sections from the library; then, the system core engine executes all the rules of the above embodiment, automatically calculates the design benchmarks of each of the nine sections according to the input hard points and the generated glass surface, and drives the modification and adjustment module to accurately locate the standard sections, forming a set of design section positions for the new car; at this time, the two-dimensional skeleton of the door has been built. Key motion verification and optimization: The hinge coordinates are initially set based on the design specifications; the system verification module immediately executes the analysis of the above embodiment and graphically displays the joint area; assuming the initial solution fails, the hinge Y-axis coordinates are adjusted according to the prompts, the system updates the hinge cross-section position in real time and re-verifies; after multiple rounds of adjustment, the verification is passed, and the hinge installation cross-section position is determined; Constructing the inner panel body and internal structure: Click to construct the inner panel; The system door inner panel construction module, based on the above embodiment, uses all the positioned sections to automatically generate the door inner panel entity through sweeping, bridging, and trimming; Subsequently, the component reinforcement construction module, based on the above embodiment, automatically extracts structural lines from the corresponding sections, generates all seven types of reinforcement plates and window regulator installation structures, and precisely assembles them onto the inner panel; Generate outer panel to complete closed loop: Click Generate Outer Panel; The system door outer panel construction module, based on the above embodiment, uses surface A as constraint and the cross-sectional structure line at the sill as internal control to automatically generate a smooth door outer panel surface; Output and Iteration: The system outputs a complete 3D digital model of the car door with detailed structure within 30 minutes, which can be directly used for preliminary CAE analysis and process review; if the styling scheme changes, only the A-face or hard point parameters need to be updated, and the process can be restarted from step 2. The new model can be generated again in a very short time.

[0061] In addition, this application also relates to a door structure modeling system, which is a functional module integrated into CAD software or a standalone computer-aided design software; the system includes: A large glass surface construction module is used to determine the large glass surface based on the glass boundary of the car door window frame. A standard section library calling module is used to call the corresponding standard section library of the door according to the door structure. The design section reference determination module is used to determine the design section reference for each section based on the door structure design parameters. The modification and adjustment module is used to adjust the standard section reference in the standard section library to the design section reference and determine the design section position. The verification module is used to determine the initial position of the door hinge according to the design specifications, perform verification analysis on the door hinge at the initial position, and determine whether the door hinge at the initial position meets the design requirements. If it does not meet the design requirements, the door hinge position is readjusted until it meets the design requirements, and the hinge installation section position is determined. The door inner panel construction module is used to output the door inner panel according to the determined design cross-sectional position, and to construct the mounting components and reinforcements on the door inner panel based on the design parameters and the determined design cross-sectional position; A door outer panel construction module is used to output the door outer panel according to the determined design cross-sectional position. The modeling system in this embodiment is a software-based and modularized version of the technical process described in the aforementioned methodological embodiment. Each module encapsulates specific algorithms and business logic, and the modules communicate and collaborate through standardized data interfaces (such as cross-sectional data, benchmark data, and surface data) to jointly complete the task of outputting a complete car door model from input parameters.

[0062] Users can operate the system through the graphical user interface provided by the system. The interface has function buttons or workflow navigation bars corresponding to the above modules. Users can enter parameters and click to execute in sequence according to the navigation steps. The system background calls the corresponding modules to perform calculations and modeling.

[0063] The modeling system in this embodiment transforms innovative design methods into a marketable, deployable, and user-friendly software tool, significantly lowering the barrier to entry for enterprises to apply this technology. All functions are centralized in one system, with seamless data flow, eliminating data loss and errors during data conversion between different software, and realizing a truly integrated design environment.

[0064] In this application, the X direction is the front-to-back direction of the vehicle, the Y direction is the left-to-right direction of the vehicle, and the Z direction is the up-to-down direction of the vehicle.

[0065] The foregoing has shown and described the basic principles, main features, and advantages of this application. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this application. Various changes and modifications can be made to this application without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of this application as claimed. The scope of protection of this application is defined by the appended claims and their equivalents.

Claims

1. A method for modeling a car door structure, characterized in that, include: The large surface area of ​​the glass is determined based on the glass boundary of the car door and window frame. Based on the door structure, call the corresponding standard door section library; Based on the door structure design parameters, determine the design section reference for each section, adjust the standard section reference in the standard section library to the design section reference, and determine the design section position. The initial position of the door hinge is determined according to the design specifications. The door hinge at the initial position is then verified and analyzed to determine whether it meets the design requirements. If the design requirements are not met, the position of the door hinges shall be readjusted until the design requirements are met, and the position of the hinge installation section shall be determined. Based on all the determined design section locations, generate the door structure model.

2. The method for modeling a car door structure according to claim 1, characterized in that, The method of calling the corresponding standard door cross-section library based on the door structure includes: calling the cross-sections at the upper hinge, lower hinge, middle limiter, upper part of the door window frame, B-pillar of the door window frame, door lock, door sill, window sill, and door anti-collision beam from the standard door cross-section library based on the door structure.

3. The method for modeling a car door structure according to claim 2, characterized in that, The method for determining the design section reference for each section based on the door structure design parameters includes: selecting the midpoint of the upper boundary of the door window frame glass along the X direction as the first reference point; obtaining the first reference plane based on the first reference point; obtaining the first intersection line between the first reference plane and the glass surface; taking the tangent line of the first intersection line at the first reference point as the first reference line; and using the first reference point, the first reference plane, and the first reference line as the design section reference for the section on the upper part of the door window frame. The B-pillar window frame trim panel is stretched in the Y direction to obtain a second intersection line with the glass surface. The midpoint of the second intersection line is taken as the second reference point. Based on the second reference point, the normal plane of the second intersection line is taken as the second reference plane. A third intersection line between the second reference plane and the glass surface is obtained. The tangent line of the third intersection line at the second reference point is taken as the second reference line. The second reference point, the second reference plane, and the second reference line are used as the design section reference for the B-pillar section of the door window frame. The spatial coordinate point of the door lock engagement is taken as the third reference point, the normal plane passing through the third reference point and perpendicular to the door hinge axis is taken as the third reference plane, and the tangent of the arc rotating around the door hinge axis passing through the third reference point is taken as the third reference line; the third reference point, the third reference plane and the third reference line are used as the design section reference for the section at the door lock.

4. The method for modeling a vehicle door structure according to claim 3, characterized in that, The method for determining the design section reference for each section based on the door structure design parameters includes: taking the midpoint of the stop at the door threshold as the fourth reference point, taking the X-direction plane passing through the fourth reference point as the fourth reference plane, and taking the Z-direction line passing through the fourth reference point as the fourth reference line; and using the fourth reference point, the fourth reference plane, and the fourth reference line as the design section reference for the section at the threshold. The intersection of the Y-direction extended surface of the water cut of the car door window sill and the glass surface is taken as the fourth phase intersection line. The midpoint of the fourth phase intersection line is taken as the fifth reference point. Based on the fifth reference point, the normal plane of the fourth phase intersection line is taken as the fifth reference plane. The tangent line of the fourth phase intersection line at the fifth reference point on the fifth reference plane is taken as the fifth reference line. The fifth reference point, the fifth reference plane, and the fifth reference line are used as the design section reference for the section at the car door window sill. Based on the design parameters of the door anti-collision beam, the trend line of the door anti-collision beam is obtained. The intersection line of the trend line extending along the Y direction and the outer panel of the door is taken as the fifth intersection line. The midpoint of the fifth intersection line is taken as the sixth reference point. Based on the sixth reference point, the normal plane of the fifth intersection line is taken as the sixth reference plane. Based on the sixth reference point, the normal line perpendicular to the outer panel of the door is taken as the sixth reference line. The sixth reference point, the sixth reference plane and the sixth reference line are used as the design section reference for the section at the door anti-collision beam.

5. The method for modeling a car door structure according to claim 4, characterized in that, The method for determining the design section reference of each section based on the door structure design parameters includes: taking the midpoint of the hinge axis of the upper hinge as the seventh reference point, taking the normal plane that passes through the seventh reference point and is perpendicular to the axis of the upper hinge as the seventh reference plane, taking the line that extends along the X direction through the seventh reference point as the seventh reference line, and taking the seventh reference point, the seventh reference plane and the seventh reference line as the design section reference of the section at the upper hinge. The midpoint of the hinge axis of the lower hinge is the eighth reference point. The normal plane that passes through the eighth reference point and is perpendicular to the axis of the lower hinge is the eighth reference plane. The line that extends along the X direction through the eighth reference point is the eighth reference line. The eighth reference point, the eighth reference plane and the eighth reference line are used as the design section references for the section at the lower hinge. The midpoint of the pivot of the middle limiter is taken as the ninth reference point, the normal plane that passes through the ninth reference point and is perpendicular to the axis of the pivot of the middle limiter is taken as the ninth reference plane, and the line that extends along the X direction through the ninth reference point is taken as the ninth reference line. The ninth reference point, the ninth reference plane and the ninth reference line are used as the design section reference for the section at the middle limiter.

6. The method for modeling a car door structure according to claim 5, characterized in that, The method for verifying and analyzing the door hinge at the initial position includes: based on the safety distance of the door outer panel motion envelope at the door hinge section at the initial position, determining the rear boundary points of the door outer panel at the upper hinge section, the lower hinge section, and the middle limiter section respectively; connecting the three rear boundary points to form the rear boundary line of the door outer panel; taking the intersection line between the mounting surface of the door hinge on the body side and the outer surface of the preliminary body styling surface after counterclockwise rotation of the structure to set the opening degree as the front boundary line; the area between the front boundary line and the rear boundary line as the seam area; if the seam area exists, it is determined that the door hinge at the current initial position meets the design requirements; otherwise, it does not meet the design requirements; if it does not meet the design requirements, the door hinge position, the door hinge tilt angle parameter, or the outer surface of the preliminary body styling surface are adjusted until a seam area exists.

7. A method for modeling a vehicle door structure according to claim 6, characterized in that, The method for generating a door structure model based on all determined design section locations includes: constructing a door opening sealing surface reference based on the determined sections at the upper hinge, lower hinge, middle limiter, upper door window frame, B-pillar of door window frame, door lock, and sill; and creating the large surface of the inner door panel based on the door opening sealing surface reference using sweeping and bridging methods. The door frame line is constructed based on the determined cross-sections at the top of the door window frame, the B-pillar of the door window frame, and the sill of the door; the side of the inner door panel is made based on the door frame line using sweeping and bridging methods. Based on the determined cross-sections at the upper hinge, lower hinge, middle limiter, upper part of the door window frame, B-pillar of the door window frame, door lock, and sill, the installation side lines required for the installation of the door sealing strip are obtained; the installation surface of the door sealing strip is made by sweeping and bridging based on the installation side lines. Based on the first reference point in the cross section of the determined door and window frame and the thickness of the edging material, the inner door panel edging surface is made by sweeping and bridging. Based on the determined cross-sections at the upper hinge, lower hinge, middle limiter, upper door window frame, B-pillar of door window frame, door lock, and sill, construct the center elevation line of the inner door panel; based on the center elevation line of the inner door panel, create the inner door panel elevation by sweeping and bridging. The inner door panel is formed by cutting the large surface, side surface, sealing strip mounting surface, edging surface, and vertical surface of the inner door panel.

8. The method for modeling a car door structure according to claim 2, characterized in that, The method for generating a door structure model based on all determined design section positions includes: using the design parameters of the door window regulator as input, generating the mounting surface and mounting hole positions of the door window regulator, and generating a data model of the door window regulator based on the mounting surface and mounting hole positions; Extract the window frame structure lines from the cross-sections at the lower hinge, the upper part of the door window frame, and the door window sill. Based on the window frame structure lines and taking the inner panel of the door as the reference, fabricate the door window frame reinforcement plate by sweeping and bridging. Extract the hinge structure lines from the cross-sections of the upper and lower hinges, and fabricate the door hinge reinforcement plate based on the hinge structure lines and the mating area of ​​the inner door panel using sweeping and bridging methods. Extract the structural line of the middle limiter from the cross section at the middle limiter, and based on the structural line of the middle limiter and taking the mating part of the inner door panel as the reference, fabricate the middle limiter reinforcement plate by sweeping and bridging. Extract the door lock structure line from the cross-section of the door lock, and based on the door lock structure line and the mating area of ​​the inner door panel, fabricate the door lock reinforcement plate by sweeping and bridging. Extract the window sill structure line of the cross section at the car door window sill, and based on the window sill structure line and the mating part of the car door inner panel, make the window sill reinforcement plate by sweeping and bridging. Extract the sill structure line of the sill section, and based on the sill structure line and the mating part of the inner door panel, make the sill reinforcement plate by sweeping and bridging. Extract the structural line of the door anti-collision beam from the cross-section of the door anti-collision beam, and based on the structural line of the door anti-collision beam and the mating area of ​​the inner door panel, fabricate the door anti-collision beam reinforcement plate by sweeping and bridging.

9. A method for modeling a vehicle door structure according to claim 6, characterized in that, The method for generating a door structure model based on all determined design section positions includes: extracting the door outer panel structure line where the anti-scratch strip is installed at the door sill; and fabricating the door outer panel by cutting and connecting the structure line at the anti-scratch strip and the preliminary shape surface of the door outer panel.

10. A vehicle door structure modeling system, characterized in that, The modeling system performs modeling according to any one of the door structure modeling methods as described in claims 1 to 9, including: A large glass surface construction module is used to determine the large glass surface based on the glass boundary of the car door window frame. A standard section library calling module is used to call the corresponding standard section library of the door according to the door structure. The design section reference determination module is used to determine the design section reference for each section based on the door structure design parameters. The modification and adjustment module is used to adjust the standard section reference in the standard section library to the design section reference and determine the design section position. The verification module is used to determine the initial position of the door hinge according to the design specifications, perform verification analysis on the door hinge at the initial position, and determine whether the door hinge at the initial position meets the design requirements. If it does not meet the design requirements, the door hinge position is readjusted until it meets the design requirements, and the hinge installation section position is determined. The door inner panel construction module is used to output the door inner panel according to the determined design cross-sectional position, and to construct the mounting components and reinforcements on the door inner panel based on the design parameters and the determined design cross-sectional position; A door outer panel construction module is used to output the door outer panel according to the determined design cross-sectional position.

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