CN117313243A - Automatic repair method, device and equipment for geometric model of automobile model - Google Patents

Abstract

The application relates to an automatic repair method, device and equipment for an automobile modeling geometric model. The method comprises the following steps: refining the sketch of the automobile product by using CAD software, and constructing the size and the position of each part accurately to obtain an automobile modeling geometric model; obtaining geometric information of a model from an automobile modeling geometric model; the geometric information comprises a three-dimensional curved surface, a three-dimensional curve, three-dimensional points and a plane center line and a plane point which are defined on each three-dimensional curved surface in the topological relation of the geometric model; discretizing the three-dimensional curve and the continuous geometry represented by the three-dimensional curve to construct the common characterization of the continuous geometry, the discrete geometry and the topological relation of the geometric model; and carrying out the deletion repair and the precision defect repair of the automobile modeling data according to the common characterization and three geometric entities of the curved surface, the curved surface and the geometric points respectively to obtain a repaired geometric model of the automobile modeling. The method can improve the repair efficiency of the geometric model of the automobile.

Description

Automatic repair method, device and equipment for geometric model of automobile model

Technical Field

The application relates to the technical field of automobile model repair, in particular to an automatic repair method, device and equipment for an automobile model geometric model.

Background

Along with the popularization of electric vehicles and the continuous pursuit of electric vehicles on battery endurance, the automobile model with lower wind resistance coefficient and better performance is designed to form the consistent demands of all manufacturers. A research result of the automobile model by Italian Pininarina company and Italian national force scientific research shows that the future automobile model takes aerodynamics as a dominant, and the automobile model has excellent aerodynamics characteristics by determining the automobile body shape according to experiments from the aerodynamics, and can meet the strict requirements of various use and production processes. Thus, the improvement and improvement of the aerodynamic properties of the automobile model are of great practical importance.

The aerodynamic performance analysis of the automobile model mainly comprises two modes, namely wind tunnel test and numerical simulation by using computational fluid dynamics (Computational Fluid Dynamics, CFD), wherein the conventional wind tunnel test result is generally high in reliability, but has many limitations, such as high wind tunnel test cost, long period and the need of manufacturing a series of oil sludge models. In addition, in wind tunnel tests, the speed, pressure and temperature values can only be measured at a limited cross section and location, and detailed information of any point in the whole flow field cannot be obtained. In contrast to wind tunnel tests, CFD is comparable in accuracy to wind tunnel tests, but almost overcomes all of its limitations. The CFD can conveniently and flexibly change initial conditions, boundary conditions and geometric boundaries, can obtain detailed information of any point of the whole flow field, and analyzes the flow field nearby the automobile, so that the automobile body is subjected to feedback adjustment, such as improvement of the head modeling, increase of the inclination angle, reduction of the height of the head edge, improvement of the bottom modeling, increase of the bottom flow velocity and the like. The aerodynamic performance design period of the vehicle model can be greatly shortened by utilizing CFD analysis, and the method is preferably faster and more effective.

The CFD analysis needs to perform grid generation on the geometric model representing the design modeling before starting numerical calculation, and the grid generation has very high requirements on the accuracy and the integrity of the geometric model, and the original input geometric model of the automobile is not considered or is difficult to predict in the design process due to the diversity of sources, so that the geometric model of the automobile needs to be repaired and simplified according to the requirement of the CFD calculation grid before grid generation.

However, at present, due to the fact that geometric models representing automobile models may have defects among geometric data of certain parts in the design and manufacturing process and may cause geometric information loss when converting data among different design software, when grid generation is performed based on the geometric models generated in the model design stage, the geometric models become dirty geometric models with noise, and grids meeting the requirements of follow-up CFD analysis cannot be directly generated, so that the geometric models need to be repaired first. Repair of geometric models typically requires extensive and cumbersome manual operations, often taking a significant amount of time.

Disclosure of Invention

Based on the above, it is necessary to provide an automatic repair method and apparatus for an automobile model geometric model, which can improve repair efficiency of the automobile geometric model.

An automatic repair method for an automobile modeling geometric model, the method comprising:

acquiring a sketch of an automobile product constructed during conceptual design;

refining the sketch of the automobile product by using CAD software, and constructing the size and the position of each part accurately to obtain an automobile modeling geometric model;

obtaining geometric information of a model from an automobile modeling geometric model; the geometric information comprises a three-dimensional curved surface, a three-dimensional curve, three-dimensional points and a plane center line and a plane point which are defined on each three-dimensional curved surface in the topological relation of the geometric model;

discretizing the three-dimensional curve and the continuous geometry represented by the three-dimensional curve to construct the common characterization of the continuous geometry, the discrete geometry and the topological relation of the geometric model;

and carrying out the deletion repair and the precision defect repair of the automobile modeling data according to the common characterization and three geometric entities of the curved surface, the curved surface and the geometric points respectively to obtain a repaired geometric model of the automobile modeling.

In one embodiment, discretizing the three-dimensional curve and the continuous geometry of the three-dimensional curved surface representation to construct a geometric model co-characterization includes:

dispersing the continuous geometry, determining the positions of discrete division points of the continuous geometry in a parameter domain, taking a node vector defined by a three-dimensional curve or a three-dimensional curved surface NURBS as a parameter coordinate of an initial discrete point, and judging whether an insertion point is required to meet the precision requirement or not through the deviation distance between adjacent discrete points to obtain the discrete representation of the curve or the curved surface;

The plane midline of the build plane parameter space is represented by a curve dispersion.

In one embodiment, the calculation of the offset distance between discrete points includes:

for three consecutive discrete points p ₁ 、p ₂ 、p ₃ The specific calculation method of the deviation distance dev comprises the following steps:

in one embodiment, constructing a face centerline of a face parameter space using curve discrete representations includes:

if the curve C and the curve S have a topological relation, the three-dimensional discrete points in the discrete representation of the curve C are also positioned on the curve S, and the corresponding coordinates of the three-dimensional discrete points of the curve C in the parameter space are found out to form a plane center line through the parameter equation of the curve S.

In one embodiment, the missing repair of the automobile modeling data comprises a topological ring repair of the curved surface, a curve repair of the topological edge and a corresponding geometric point repair of the vertex; the precision defect repair comprises geometric precision defect repair and topology precision defect repair; according to the common characterization, the method carries out the deletion repair and the precision defect repair of the automobile modeling data according to three geometric entities of a curved surface, a curve and a geometric point, and comprises the following steps:

according to the common characterization, carrying out missing repair on the automobile modeling data according to three geometric entities of a curved surface, a curve and geometric points, and establishing four surface central lines connected end to end and topological edges at the boundary of the curved surface of a parameter space to form a topological ring to complete the topological ring repair of the curved surface;

Reconstructing by using a surface center line corresponding to the topological edge and a non-degenerate closed smooth curved surface, extracting a curve where the boundary is located according to a non-degenerate closed smooth curved surface equation if the surface center line is positioned at a parameter space boundary, and segmenting the extracted curve through a parameter coordinate interval of the surface center line; if the surface center line is positioned in the parameter space, discrete points of the surface center line are used as initial point sequences, whether the precision requirement is met by inserting points is judged through the deviation distance between adjacent discrete points, under the condition that the precision requirement is met, the parameter coordinates of the discrete points are converted into three-dimensional coordinates through a non-degenerate closed smooth curved surface equation, and a first-order non-degenerate closed smooth curve is established by taking the discrete points as control vertexes to complete curve restoration of the topological edge;

and reconstructing and repairing the missing geometric points by using the start-stop coordinate points which are represented by the corresponding topological edges in a discrete manner to obtain the repaired geometric points.

In one embodiment, judging whether the curved surface has precision defects, if so, detecting the precision defect type of the curved surface according to the intersection of the curved surface, and repairing the precision defect of the curved surface according to the precision defect type;

and detecting precision defects of the curves according to the continuity of the central lines of the adjacent surfaces, and repairing the precision defects of the curves according to the types of the precision defects.

In one embodiment, judging whether the curved surface has an accuracy defect, if the curved surface has the accuracy defect, detecting the type of the accuracy defect of the curved surface according to the intersection of the curved surface, and repairing the accuracy defect of the curved surface according to the type of the accuracy defect, including:

finding two adjacent topological surfaces and two topological edges positioned at the intersection line on each topological surface according to the topological relation, calculating Hausdorff distance between the corresponding geometric curves of the two topological edges, determining the curve overlap ratio according to the Hausdorff distance, and judging whether the curved surface has an accuracy defect according to the curve overlap ratio;

if the curved surface has the precision defect, intersecting the two curved surfaces with the precision defect, if the curved surface has the intersecting line, belonging to the topology precision defect, taking the intersecting line as a new topology edge, and updating corresponding three-dimensional curve data; if no intersection line exists, the geometric precision defect is overcome, and the curved surface is restored in an extending or filling mode.

In one embodiment, the method for detecting the precision defect of the curve based on the continuity of the center line of the adjacent surface and repairing the precision defect of the curve according to the precision defect type comprises the following steps:

intersecting the surface central lines which are topologically connected, if an actual intersection point exists, and the distance between the intersection point and a common endpoint is larger than the tolerance, taking the new intersection point as the endpoint of the surface central line, and if the distance between the intersection point and the common endpoint is smaller than the tolerance, keeping unchanged; if the actual intersection point does not exist, but common endpoints or actual intersection points exist between the surface central lines of the topological connection and the central lines of other surfaces, exchanging storage positions of the corresponding surface central lines, and connecting the actually connected surface central lines in series to realize topology precision defect repair;

Intersecting the surface central lines connected in a topology, if an actual intersection point exists, the distance between the intersection point and a common endpoint is equal to the tolerance, or the actual intersection point does not exist, and meanwhile, the common endpoint or the actual intersection point does not exist between the surface central lines connected in the topology and other surface central lines, geometric precision repairing is carried out on the curve, the surface central line is established by the endpoint at the notch, and geometric entity curve reconstruction is carried out by utilizing the surface central line corresponding to the topology edge and the non-degenerate closed smooth curved surface, so that geometric precision defect repairing of the curve is realized;

when the distance between the coordinates of the geometric point and the starting point and the ending point of the curve is larger than the tolerance, judging that the geometric point is defective in precision, deleting the wrong geometric point, and reconstructing and repairing the missing geometric point by utilizing the starting point and the ending point coordinate points which are discretely represented by the corresponding topological edges to obtain the repaired geometric point.

An automatic repair device for an automotive modeling geometric model, the device comprising:

an automobile modeling geometric model module is constructed and used for acquiring an automobile product sketch constructed during conceptual design; refining the sketch of the automobile product by using CAD software, and constructing the size and the position of each part accurately to obtain an automobile modeling geometric model;

the geometric information acquisition module is used for acquiring geometric information of the model from the geometric model of the automobile model; the geometric information comprises a three-dimensional curved surface, a three-dimensional curve, three-dimensional points and a plane center line and a plane upper point which are defined on each three-dimensional curved surface in the topological relation of the geometric model;

The discretization module is used for discretizing the three-dimensional curve and the continuous geometry represented by the three-dimensional curve to construct the common characterization of the continuous geometry, the discrete geometry and the topological relation of the geometric model;

and the defect repair module is used for carrying out the defect repair and the precision defect repair of the automobile modeling data according to the three geometric entities of the curved surface, the curved surface and the geometric points respectively according to the common characterization, so as to obtain a repaired geometric model of the automobile modeling.

A computer device comprising a memory storing a computer program and a processor which when executing the computer program performs the steps of:

acquiring a sketch of an automobile product constructed during conceptual design;

refining the sketch of the automobile product by using CAD software, and constructing the size and the position of each part accurately to obtain an automobile modeling geometric model;

obtaining geometric information of a model from an automobile modeling geometric model; the geometric information comprises a three-dimensional curved surface, a three-dimensional curve, three-dimensional points and a plane center line and a plane point which are defined on each three-dimensional curved surface in the topological relation of the geometric model;

discretizing the three-dimensional curve and the continuous geometry represented by the three-dimensional curve to construct the common characterization of the continuous geometry, the discrete geometry and the topological relation of the geometric model;

And carrying out the deletion repair and the precision defect repair of the automobile modeling data according to the common characterization and three geometric entities of the curved surface, the curved surface and the geometric points respectively to obtain a repaired geometric model of the automobile modeling.

According to the automatic repair method, device and equipment for the automobile model geometric model, the common characterization based on the continuous geometric, discrete geometric and topological relation is established in the reading-in stage of the automobile geometric model subjected to CFD analysis, so that the processing flow of geometric repair and feature simplification of the automobile geometric model is greatly optimized, meanwhile, aiming at the problem that the automobile model cannot be directly used for aerodynamic design analysis, the missing repair and the precision defect repair of automobile model data are respectively carried out according to three geometric entities of a curved surface, a curve and a geometric point according to the common characterization, the automobile geometric model is automatically repaired to meet the grid generation requirement, the manual repair process of time and labor waste in the middle is avoided, and the repair efficiency of the automobile model geometric model is greatly improved.

Drawings

FIG. 1 is a flow chart of an automatic repair method for geometric models of automobile models in one embodiment;

FIG. 2 is a geometric model of an automobile model in one embodiment;

FIG. 3 is a schematic diagram of the continuous geometry, discrete geometry, and topology of a method for co-characterization of vehicle styling in one embodiment;

FIG. 4 is a schematic representation of the discrete results after a continuous NURBS surface is run in another embodiment;

FIG. 5 is a schematic diagram of a topology reconstruction process for a curved surface with topology missing in one embodiment;

FIG. 6 is a schematic diagram of surface accuracy defect classification in one embodiment;

FIG. 7 is a schematic diagram of a curve precision defect classification and repair process in one embodiment;

FIG. 8 is a block diagram of an automatic repair device for geometric models of automobile models in one embodiment;

fig. 9 is an internal structural diagram of a computer device in one embodiment.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application.

In one embodiment, as shown in fig. 1, there is provided an automatic repair method for an automobile model geometry model, comprising the steps of:

step 102, obtaining a sketch of an automobile product constructed during conceptual design; and (3) refining the sketch of the automobile product by using CAD software, and constructing the geometric model of the automobile model by accurately constructing the sizes and positions of all the parts.

The process of refining the sketch of the automobile product by utilizing CAD software and constructing the size and the position of each part accurately to obtain the geometric model of the automobile model is the prior art, and redundant description is not made in the application.

104, obtaining geometric information of a model from an automobile modeling geometric model; the geometric information comprises a three-dimensional curved surface, a three-dimensional curve, three-dimensional points and surface center lines and surface points defined on each three-dimensional curved surface in the topological relation of the geometric model.

In the geometric model, the topological entities all have corresponding geometric entities. For example, a topological surface represents an area of a corresponding three-dimensional surface after one or more cuts, which is generally referred to as a cut surface, and the effective parameter domain after cutting is generally a part of the parameter domain of the original surface, and the cut surface can accurately represent the defined area. Thus, the topology surface typically needs to include a parametric equation representing the original surface and a topology ring defining the region, wherein the topology surface must include a topology outer ring defining the contour boundary of the outermost edge of the region, and one or more topology inner rings may be present, representing the region of holes present within the region. Each topological ring is composed of a series of topological edges, and all topological edges in a single topological ring are connected end to form a closed loop; the topological edge is a component part of the boundary of the topological face and is also a tie of the connection relation of the topological face, and the topological edge has a geometric solid curve correspondingly defined in a three-dimensional space. The curve is positioned on the curved surface, so that a two-dimensional surface center line corresponds to the curve in the parameter space of the curved surface; a topological point is a boundary of a topological line that has a geometrical solid point defined correspondingly in three-dimensional space. The topological points or topological edges on different surfaces may correspond to the same vertex or curve of the three-dimensional space.

In the design of automotive modeling, non-uniform rational B-splines (NURBS) methods are widely used to describe curved surfaces and curves. A NURBS curve p (u) passes through the order k and the weight omega _i (i=0, 1,., n), control vertex d _i (i=0, 1,) n) and node vector u= [ U ] ₀ ,u ₁ ,...,u _n+k+1 ]Definition is performed. The node vector gives the parameter domain of the curve and simultaneously gives the basis function N in the parameter equation _i,k A definition is made. The curve p (U, V) is obtained by generalizing the definition of the curve, and given two-direction parameters, the U-direction order k and the V-direction order l, and the weight omega _ij And control vertex d _ij (i=0, 1.., m; j=0, 1., n.), U-direction node vector u= [ U ] ₀ ,u ₁ ,...,u _m+k+1 ]Vector v= [ V ] with V-direction node ₀ ,v ₁ ,...,v _n+l+1 ]. The parameter equations of NURBS curve and curved surface are respectively:

curve:

curved surface:

the surface parameter space refers to the parameter domain of a three-dimensional surface, i.e., (u, v), u ₀ ≤u≤u _m+k+1 ,v ₀ ≤v≤v _n+l+1 . The coordinates of any point (u ', v') in the curved surface parameter space corresponding to the three-dimensional space are (p) _x (u',v'),p _y (u',v'),p _z (u',v'))。

Taking fig. 2 as an example, geometric model parameters of an automobile model are obtained, and a maximum grid cell size L is specified to assist geometric repair, wherein geometric information in the automobile model includes three-dimensional curved surfaces (numbers, orders, weight factors, control vertexes, node vectors) and three-dimensional points (numbers, three-dimensional coordinates) in geometric entities, and plane central lines (corresponding three-dimensional curve numbers) and plane upper points (corresponding three-dimensional point numbers) defined on each three-dimensional curved surface in topological relation.

And 106, discretizing the three-dimensional curve and the continuous geometry represented by the three-dimensional curved surface to construct the common characterization of the continuous geometry, the discrete geometry and the topological relation of the geometric model.

Discretizing the continuous geometry of the curve and the curved surface representation to obtain a corresponding discrete representation, and constructing the common characterization of the continuous geometry, the discrete geometry and the topological relation, as shown in figure 3. The discrete representation is constructed as follows:

2.1.1 discretizing the continuous geometry, determining the position of discrete division points of the continuous geometry in the parameter domain. The node vector defined by the curve or the curved surface NURBS is used as the parameter coordinate of the initial discrete point, then whether the insertion point is needed to meet the precision requirement is judged through the deviation distance between the adjacent discrete points, and the result after the curved surface is discrete in the parameter domain is shown in figure 4. For three consecutive discrete points p ₁ 、p ₂ 、p ₃ The specific calculation method of the deviation distance dev comprises the following steps:

if dev < mu indicates that the accuracy requirement is satisfied, where mu is the maximum offset distance and its value is mu=max (box _{Long length} ，box _{Wide width of} ，box _{High height} )×0.001，box _{Long length} ，box _{Wide width of} ，box _{High height} Is the three-dimensional size of a cuboid that just encloses the geometric solid.

2.1.2 the plane midline of the build plane parameter space is represented by a curvilinear dispersion. If the curve C and the curve S have a topological relation, the three-dimensional discrete points in the discrete representation of the curve C are also positioned on the curve S, and the corresponding coordinates of the three-dimensional discrete points of the curve C in the parameter space are found out through the parameter equation of the curve S, so that a plane center line is formed. As shown in fig. 4, the three-dimensional curve indicated by the arrow as the boundary of the curved surface constructs a corresponding surface centerline in the parameter space. According to the method, the common characterization based on the continuous geometry, the discrete geometry and the topological relation is established for the automobile geometric model subjected to CFD analysis in the reading-in stage, so that the processing flow of geometric restoration and feature simplification of the automobile geometric model is greatly optimized.

And step 108, carrying out missing repair and precision defect repair on the automobile modeling data according to the three geometric entities of the curved surface, the curved surface and the geometric points according to the common characterization, and obtaining a repaired geometric model of the automobile modeling.

2.2.1, the missing repair of the automobile modeling data is respectively processed according to three geometric entities of a curved surface, a curve and a geometric point:

(1) The curved surface lacks a topological ring. As shown in fig. 5, the specific process includes: establishing four-surface center lines connected end to end at curved surface boundary of parameter spaceWith topological edge p' _n (u) (n=1, 2,3, 4) constitutes a topology ring, and simultaneously constitutes a containment relationship between the topology ring and the topology face, and between the topology ring and the topology edge.

(2) The topological edge lacks a corresponding curve. And reconstructing the NURBS curved surface by using the surface central line corresponding to the topological edge. If the plane center line is positioned at the parameter space boundary, extracting curve parameters of the boundary according to the NURBS curved surface equation, and segmenting the extracted curve through a parameter coordinate interval of the plane center line; if the plane center line is positioned in the parameter space, taking the discrete points of the plane center line as an initial point sequence, adopting the method of 2.1.1 steps to judge whether the insertion point is needed to meet the precision requirement through the offset distance between the adjacent discrete points, converting the parameter coordinates of the discrete points into three-dimensional coordinates through a NURBS curved surface equation, and finally taking the discrete points as control vertexes to establish a first-order NURBS curve.

(3) Vertices lack corresponding geometric points. And reconstructing and repairing the missing geometric points by using the start-stop coordinate points which are discretely represented by the corresponding topological edges.

2.2.2 precision defect repair of automobile modeling data can be divided into geometric precision defects and topological precision defects, and repair is carried out according to three types of geometric entities of curved surfaces, curves and geometric points:

detecting whether the curved surface has precision defects or not and repairing the curved surface according to different types:

(1) Finding two adjacent topology sides at the intersection of the topology sides through topological relation;

(2) And calculating Hausdorff distance between the two topological edges corresponding to the geometric curves, and judging whether the curved surface has the precision defect or not according to the curve coincidence degree. The calculation flow of Hausdorff distance of the curved surface-curved surface and the curved surface-curved surface is as follows: and calculating the projection distance from a discrete point in the discrete representation of the curved surface or curve to the other curved surface or curve, wherein the maximum value of all projection distances in the two curved surfaces or curves is Hausdorff distance. The projection distance from a discrete point to a curve or curved surface is equivalent to the shortest distance from the point to the curve or curved surface.

(3) Aiming at two curved surfaces with precision defects, intersecting the curved surfaces, if intersecting lines exist on the curved surfaces, belonging to the topology precision defects, taking the intersecting lines as new topology edges, and updating corresponding three-dimensional curve data; if no intersection line exists, the geometric accuracy defect is overcome, and the curved surface is repaired in an extending or filling mode, as shown in fig. 6, which is a schematic diagram of the accuracy defect of the curved surface. The geometric accuracy defect repair of the curved surface adopts the conditions of two methods of extending or filling the curved surface: extending the curved surface by the distance of the maximum grid unit size L, at the moment, intersecting the curved surface, and if intersecting lines exist between the extended curved surfaces, updating the corresponding geometric data of the extended curved surfaces and the intersecting lines; and if the curved surfaces are not intersected, a curved surface is newly built on the basis of the boundary of the two curved surfaces to carry out filling repair.

Whether the detection curve has precision defects or not is judged according to the continuity of the lines in the adjacent surfaces as shown in fig. 7, and the precision defects are respectively processed:

(1) And solving intersection of the surface central lines which are topologically connected, and taking the new intersection point as an endpoint of the surface central line if the actual intersection point exists and the distance between the intersection point and the common endpoint is larger than the tolerance epsilon. The tolerance calculation method is epsilon=max (box _{Long length} ，box _{Wide width of} ，box _{High height} )×10 ^-9 Wherein the box _{Long length} ，box _{Wide width of} ，box _{High height} Is the three-dimensional size of a cuboid that just encloses the geometric solid. If the distance between the intersection point and the common endpoint is smaller than the tolerance epsilon, the distance is kept unchanged. If the actual intersection point does not exist, but a common endpoint or the actual intersection point exists between the two face center lines, the corresponding face center line storage positions are exchanged, and the face center lines which are actually connected are connected in series.

(2) If the two conditions are not satisfied, the geometric accuracy defect is generated by creating a surface center line at the end point of the notch, and reconstructing a corresponding geometric entity curve by using the steps of 2.2.1 (2).

(3) And detecting the geometric point precision defect, and judging the geometric point precision defect when the distance between the coordinates of the geometric point and the starting point and the ending point of the curve is larger than the tolerance epsilon. At this point the erroneous geometric points should be deleted and the corresponding geometric points reconstructed using the procedure described in 2.2.1 (3).

According to the common characterization, the missing repair and the precision defect repair of the automobile modeling data are respectively carried out according to three geometric entities of the curved surface, the curved line and the geometric points, the automobile geometric model is automatically repaired to meet the grid generation requirement, the manual repair process of time and labor waste in the middle is avoided, and the repair efficiency of the automobile modeling geometric model is greatly improved.

In the automatic repair method for the automobile model geometric model, the common characterization based on continuous geometric, discrete geometric and topological relations is established in the reading-in stage of the automobile geometric model subjected to CFD analysis, so that the processing flow of geometric repair and feature simplification of the automobile geometric model is greatly optimized, meanwhile, the defect repair and the precision defect repair of automobile model data are respectively carried out according to three geometric entities of a curved surface, a curve and geometric points according to the common characterization aiming at the problem that the automobile model cannot be directly used for aerodynamic design analysis, the automobile geometric model is automatically repaired to meet the grid generation requirement, the middle time-consuming and labor-consuming manual repair process is avoided, and the repair efficiency of the automobile model geometric model is greatly improved.

In one embodiment, discretizing the three-dimensional curve and the continuous geometry of the three-dimensional curved surface representation to construct a geometric model co-characterization includes:

Dispersing the continuous geometry, determining the positions of discrete division points of the continuous geometry in a parameter domain, taking a node vector defined by a three-dimensional curve or a three-dimensional curved surface NURBS as a parameter coordinate of an initial discrete point, and judging whether an insertion point is required to meet the precision requirement or not through the deviation distance between adjacent discrete points to obtain the discrete representation of the curve or the curved surface;

the plane midline of the build plane parameter space is represented by a curve dispersion.

In one embodiment, the calculation of the offset distance between discrete points includes:

for three consecutive discrete points p ₁ 、p ₂ 、p ₃ The specific calculation method of the deviation distance dev comprises the following steps:

in one embodiment, constructing a face centerline of a face parameter space using curve discrete representations includes:

if the curve C and the curve S have a topological relation, the three-dimensional discrete points in the discrete representation of the curve C are also positioned on the curve S, and the corresponding coordinates of the three-dimensional discrete points of the curve C in the parameter space are found out to form a plane center line through the parameter equation of the curve S.

In one embodiment, the missing repair of the automobile modeling data comprises a topological ring repair of the curved surface, a curve repair of the topological edge and a corresponding geometric point repair of the vertex; the precision defect repair comprises geometric precision defect repair and topology precision defect repair; according to the common characterization, the method carries out the deletion repair and the precision defect repair of the automobile modeling data according to three geometric entities of a curved surface, a curve and a geometric point, and comprises the following steps:

According to the common characterization, carrying out missing repair on the automobile modeling data according to three geometric entities of a curved surface, a curve and geometric points, and establishing four surface central lines connected end to end and topological edges at the boundary of the curved surface of a parameter space to form a topological ring to complete the topological ring repair of the curved surface;

reconstructing by using a surface center line corresponding to the topological edge and a non-degenerate closed smooth curved surface, extracting a curve where the boundary is located according to a non-degenerate closed smooth curved surface equation if the surface center line is positioned at a parameter space boundary, and segmenting the extracted curve through a parameter coordinate interval of the surface center line; if the surface center line is positioned in the parameter space, discrete points of the surface center line are used as initial point sequences, whether the precision requirement is met by inserting points is judged through the deviation distance between adjacent discrete points, under the condition that the precision requirement is met, the parameter coordinates of the discrete points are converted into three-dimensional coordinates through a non-degenerate closed smooth curved surface equation, and a first-order non-degenerate closed smooth curve is established by taking the discrete points as control vertexes to complete curve restoration of the topological edge;

and reconstructing and repairing the missing geometric points by using the start-stop coordinate points which are represented by the corresponding topological edges in a discrete manner to obtain the repaired geometric points.

In a specific embodiment, a curve where the boundary is located is extracted according to a non-degenerate closed smooth curved surface equation, the extracted curve is segmented through a parameter coordinate interval of a plane center line, and the discrete point parameter coordinates are converted into three-dimensional coordinates through the non-degenerate closed smooth curved surface equation under the condition that the precision requirement is met, so that redundant description is omitted in the application.

In one embodiment, judging whether the curved surface has precision defects, if so, detecting the precision defect type of the curved surface according to the intersection of the curved surface, and repairing the precision defect of the curved surface according to the precision defect type;

and detecting precision defects of the curves according to the continuity of the central lines of the adjacent surfaces, and repairing the precision defects of the curves according to the types of the precision defects.

In one embodiment, judging whether the curved surface has an accuracy defect, if the curved surface has the accuracy defect, detecting the type of the accuracy defect of the curved surface according to the intersection of the curved surface, and repairing the accuracy defect of the curved surface according to the type of the accuracy defect, including:

finding two adjacent topological surfaces and two topological edges positioned at the intersection line on each topological surface according to the topological relation, calculating Hausdorff distance between the corresponding geometric curves of the two topological edges, determining the curve overlap ratio according to the Hausdorff distance, and judging whether the curved surface has an accuracy defect according to the curve overlap ratio;

if the curved surface has the precision defect, intersecting the two curved surfaces with the precision defect, if the curved surface has the intersecting line, belonging to the topology precision defect, taking the intersecting line as a new topology edge, and updating corresponding three-dimensional curve data; if no intersection line exists, the geometric precision defect is overcome, and the curved surface is restored in an extending or filling mode.

In a specific embodiment, whether the curved surface has an accuracy defect is determined according to the curve overlap ratio, and the tolerance is calculated first, where the tolerance calculation method is epsilon=max (box _{Long length} ，box _{Wide width of} ，box _{High height} )×10 ^-9 Wherein the box _{Long length} ，box _{Wide width of} ，box _{High height} Is the three-dimensional size of a cuboid that just encloses the geometric solid. And if the curve coincidence degree is smaller than the tolerance, judging coincidence.

In one embodiment, the method for detecting the precision defect of the curve based on the continuity of the center line of the adjacent surface and repairing the precision defect of the curve according to the precision defect type comprises the following steps:

intersecting the surface central lines which are topologically connected, if an actual intersection point exists, and the distance between the intersection point and a common endpoint is larger than the tolerance, taking the new intersection point as the endpoint of the surface central line, and if the distance between the intersection point and the common endpoint is smaller than the tolerance, keeping unchanged; if the actual intersection point does not exist, but common endpoints or actual intersection points exist between the surface central lines of the topological connection and the central lines of other surfaces, exchanging storage positions of the corresponding surface central lines, and connecting the actually connected surface central lines in series to realize topology precision defect repair;

intersecting the surface central lines connected in a topology, if an actual intersection point exists, the distance between the intersection point and a common endpoint is equal to the tolerance, or the actual intersection point does not exist, and meanwhile, the common endpoint or the actual intersection point does not exist between the surface central lines connected in the topology and other surface central lines, geometric precision repairing is carried out on the curve, the surface central line is established by the endpoint at the notch, and geometric entity curve reconstruction is carried out by utilizing the surface central line corresponding to the topology edge and the non-degenerate closed smooth curved surface, so that geometric precision defect repairing of the curve is realized;

When the distance between the coordinates of the geometric point and the starting point and the ending point of the curve is larger than the tolerance, judging that the geometric point is defective in precision, deleting the wrong geometric point, and reconstructing and repairing the missing geometric point by utilizing the starting point and the ending point coordinate points which are discretely represented by the corresponding topological edges to obtain the repaired geometric point.

It should be understood that, although the steps in the flowchart of fig. 1 are shown in sequence as indicated by the arrows, the steps are not necessarily performed in sequence as indicated by the arrows. The steps are not strictly limited to the order of execution unless explicitly recited herein, and the steps may be executed in other orders. Moreover, at least some of the steps in fig. 1 may include multiple sub-steps or stages that are not necessarily performed at the same time, but may be performed at different times, nor do the order in which the sub-steps or stages are performed necessarily performed in sequence, but may be performed alternately or alternately with at least a portion of other steps or sub-steps of other steps.

In one embodiment, as shown in fig. 8, there is provided an automatic repair device for geometric model of automobile model, comprising: an automobile modeling geometric model module 802, a geometric information acquisition module 804, a discretization module 806, and a defect repair module 808 are constructed, wherein:

A build automotive modeling geometry model module 802 for obtaining a sketch of an automotive product built at the time of conceptual design; refining the sketch of the automobile product by using CAD software, and constructing the size and the position of each part accurately to obtain an automobile modeling geometric model;

a geometric information obtaining module 804, configured to obtain geometric information of a model from the geometric model of the automobile model; the geometric information comprises a three-dimensional curved surface, a three-dimensional curve, three-dimensional points and a plane center line and a plane upper point which are defined on each three-dimensional curved surface in the topological relation of the geometric model;

a discretization module 806, configured to discretize the three-dimensional curve and the continuous geometry represented by the three-dimensional curve to construct a common characterization of continuous geometry, discrete geometry, and topological relation of the geometric model;

and the defect repair module 808 is configured to perform missing repair and precision defect repair on the vehicle modeling data according to the three geometric entities of the curved surface, the curved surface and the geometric points according to the common characterization, so as to obtain a repaired geometric model of the vehicle modeling.

For specific limitations on an automatic repair device for an automobile model geometry model, reference may be made to the above description of a method for automatically repairing an automobile model geometry model, which is not repeated herein. The modules in the automatic repairing device for the geometric model of the automobile model can be fully or partially realized by software, hardware and a combination thereof. The above modules may be embedded in hardware or may be independent of a processor in the computer device, or may be stored in software in a memory in the computer device, so that the processor may call and execute operations corresponding to the above modules.

In one embodiment, a computer device is provided, which may be a terminal, and the internal structure thereof may be as shown in fig. 9. The computer device includes a processor, a memory, a network interface, a display screen, and an input device connected by a system bus. Wherein the processor of the computer device is configured to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The network interface of the computer device is used for communicating with an external terminal through a network connection. The computer program, when executed by the processor, implements a method for automatically repairing a geometric model of an automobile model. The display screen of the computer equipment can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer equipment can be a touch layer covered on the display screen, can also be keys, a track ball or a touch pad arranged on the shell of the computer equipment, and can also be an external keyboard, a touch pad or a mouse and the like.

It will be appreciated by those skilled in the art that the structure shown in fig. 9 is merely a block diagram of a portion of the structure associated with the present application and is not limiting of the computer device to which the present application applies, and that a particular computer device may include more or fewer components than shown, or may combine some of the components, or have a different arrangement of components.

In an embodiment a computer device is provided comprising a memory storing a computer program and a processor implementing the steps of the method of the above embodiments when the computer program is executed.

Those skilled in the art will appreciate that implementing all or part of the above described methods may be accomplished by way of a computer program stored on a non-transitory computer readable storage medium, which when executed, may comprise the steps of the embodiments of the methods described above. Any reference to memory, storage, database, or other medium used in the various embodiments provided herein may include non-volatile and/or volatile memory. The nonvolatile memory can include Read Only Memory (ROM), programmable ROM (PROM), electrically Programmable ROM (EPROM), electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms such as Static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double Data Rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous Link DRAM (SLDRAM), memory bus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM), among others.

The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples merely represent a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the invention. It should be noted that it would be apparent to those skilled in the art that various modifications and improvements could be made without departing from the spirit of the present application, which would be within the scope of the present application. Accordingly, the scope of protection of the present application is to be determined by the claims appended hereto.

Claims (10)

1. An automatic repair method for an automobile modeling geometric model, which is characterized by comprising the following steps:

acquiring a sketch of an automobile product constructed during conceptual design;

refining the sketch of the automobile product by using CAD software, and constructing the size and the position of each part accurately to obtain an automobile modeling geometric model;

obtaining geometric information of a model from the geometric model of the automobile model; the geometric information comprises a three-dimensional curved surface, a three-dimensional curve, three-dimensional points and a plane center line and a plane upper point which are defined on each three-dimensional curved surface in the topological relation of the geometric model;

Discretizing the three-dimensional curve and the continuous geometry represented by the three-dimensional curve to construct the common characterization of the continuous geometry, the discrete geometry and the topological relation of the geometric model;

and carrying out missing repair and precision defect repair on the automobile modeling data according to the common characterization and three geometric entities of the curved surface, the curved surface and the geometric points respectively to obtain a repaired geometric model of the automobile modeling.

2. The method of claim 1, wherein discretizing the three-dimensional curve and the continuous geometry of the three-dimensional curved surface representation to construct a geometric model co-characterization comprises:

dispersing the continuous geometry, determining the positions of discrete division points of the continuous geometry in a parameter domain, taking a node vector defined by a three-dimensional curve or a three-dimensional curved surface NURBS as a parameter coordinate of an initial discrete point, and judging whether an insertion point is required to meet the precision requirement or not through the deviation distance between adjacent discrete points to obtain the discrete representation of the curve or the curved surface;

the plane midline of the build plane parameter space is represented by a curve dispersion.

3. The method of claim 2, wherein the calculating of the offset distance between the discrete points comprises:

for three consecutive discrete points p ₁ 、p ₂ 、p ₃ The specific calculation method of the deviation distance dev comprises the following steps:

4. the method of claim 2, wherein constructing the face centerline of the face parameter space using the curvilinear discrete representation comprises:

if the curve C and the curve S have a topological relation, the three-dimensional discrete points in the discrete representation of the curve C are also positioned on the curve S, and the corresponding coordinates of the three-dimensional discrete points of the curve C in the parameter space are found out to form a plane center line through the parameter equation of the curve S.

5. The method of claim 3, wherein the missing repair of the vehicle modeling data includes a topology ring repair of the curved surface, a curve repair of the topology edge, and a corresponding geometric point repair of the vertex; the precision defect repair comprises geometric precision defect repair and topology precision defect repair; according to the common characterization, carrying out the deletion repair and the precision defect repair of the automobile modeling data according to three geometric entities of a curved surface, a curve and a geometric point respectively, wherein the method comprises the following steps:

according to the common characterization, carrying out missing repair on the automobile modeling data according to three geometric entities of a curved surface, a curved surface and geometric points, and establishing four surface center lines connected end to end and topology edges at the boundary of the curved surface of a parameter space to form a topology ring to complete the topology ring repair of the curved surface;

Reconstructing by using a surface center line corresponding to the topological edge and a non-degenerate closed smooth curved surface, extracting a curve where the boundary is located according to a non-degenerate closed smooth curved surface equation if the surface center line is positioned at a parameter space boundary, and segmenting the extracted curve through a parameter coordinate interval of the surface center line; if the surface center line is positioned in the parameter space, discrete points of the surface center line are used as initial point sequences, whether the precision requirement is met by inserting points is judged through the deviation distance between adjacent discrete points, under the condition that the precision requirement is met, the parameter coordinates of the discrete points are converted into three-dimensional coordinates through a non-degenerate closed smooth curved surface equation, and a first-order non-degenerate closed smooth curve is established by taking the discrete points as control vertexes to complete curve restoration of the topological edge;

and reconstructing and repairing the missing geometric points by using the start-stop coordinate points which are represented by the corresponding topological edges in a discrete manner to obtain the repaired geometric points.

6. The method of claim 5, wherein the method further comprises:

judging whether the curved surface has precision defects or not, if so, detecting the precision defect type of the curved surface according to the intersection of the curved surface, and repairing the precision defect of the curved surface according to the precision defect type;

And detecting precision defects of the curves according to the continuity of the central lines of the adjacent surfaces, and repairing the precision defects of the curves according to the types of the precision defects.

7. The method of claim 6, wherein determining whether the surface has a precision defect, if so, performing precision defect type detection on the surface according to the intersection of the surfaces, and performing surface precision defect repair according to the precision defect type, comprises:

finding two adjacent topological surfaces and two topological edges positioned at the intersection line on each topological surface according to the topological relation, calculating Hausdorff distance between the corresponding geometric curves of the two topological edges, determining the curve overlap ratio according to the Hausdorff distance, and judging whether the curved surface has an accuracy defect according to the curve overlap ratio;

if the curved surface has the precision defect, intersecting the two curved surfaces with the precision defect, if the curved surface has the intersecting line, belonging to the topology precision defect, taking the intersecting line as a new topology edge, and updating corresponding three-dimensional curve data; if no intersection line exists, the geometric precision defect is overcome, and the curved surface is restored in an extending or filling mode.

8. The method of claim 7, wherein the precision defect detection of the curve based on the continuity of the lines in the adjacent surfaces and the repair of the precision defect of the curve based on the type of the precision defect comprise:

Intersecting the surface central lines which are topologically connected, if an actual intersection point exists, and the distance between the intersection point and a common endpoint is larger than the tolerance, taking the new intersection point as the endpoint of the surface central line, and if the distance between the intersection point and the common endpoint is smaller than the tolerance, keeping unchanged; if the actual intersection point does not exist, but common endpoints or actual intersection points exist between the surface central lines of the topological connection and the central lines of other surfaces, exchanging storage positions of the corresponding surface central lines, and connecting the actually connected surface central lines in series to realize topology precision defect repair;

intersecting the surface central lines connected in a topology, if an actual intersection point exists, the distance between the intersection point and a common endpoint is equal to the tolerance, or the actual intersection point does not exist, and meanwhile, the common endpoint or the actual intersection point does not exist between the surface central lines connected in the topology and other surface central lines, geometric precision repairing is carried out on the curve, the surface central line is established by the endpoint at the notch, and geometric entity curve reconstruction is carried out by utilizing the surface central line corresponding to the topology edge and the non-degenerate closed smooth curved surface, so that geometric precision defect repairing of the curve is realized;

when the distance between the coordinates of the geometric point and the starting point and the ending point of the curve is larger than the tolerance, judging that the geometric point is defective in precision, deleting the wrong geometric point, and reconstructing and repairing the missing geometric point by utilizing the starting point and the ending point coordinate points which are discretely represented by the corresponding topological edges to obtain the repaired geometric point.

9. An automatic repair device for an automobile modeling geometric model, characterized in that the device comprises:

an automobile modeling geometric model module is constructed and used for acquiring an automobile product sketch constructed during conceptual design; refining the sketch of the automobile product by using CAD software, and constructing the size and the position of each part accurately to obtain an automobile modeling geometric model;

the geometric information acquisition module is used for acquiring geometric information of the model from the geometric model of the automobile model; the geometric information comprises a three-dimensional curved surface, a three-dimensional curve, three-dimensional points and a plane center line and a plane upper point which are defined on each three-dimensional curved surface in the topological relation of the geometric model;

the discretization module is used for discretizing the three-dimensional curve and the continuous geometry represented by the three-dimensional curve to construct the common characterization of the continuous geometry, the discrete geometry and the topological relation of the geometric model;

and the defect repair module is used for carrying out the defect repair and the precision defect repair of the automobile modeling data according to the three geometric entities of the curved surface, the curved surface and the geometric points respectively according to the common characterization, so as to obtain a repaired geometric model of the automobile modeling.

10. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor implements the steps of the method of any of claims 1 to 8 when the computer program is executed.