CN104615078B - Method for recognizing characteristics of bending side of aircraft sheet metal based on topological adjacent performance - Google Patents
Method for recognizing characteristics of bending side of aircraft sheet metal based on topological adjacent performance Download PDFInfo
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Abstract
The invention relates to a method for recognizing characteristics of a bending side of aircraft sheet metal based on topological adjacent performance, and belongs to the technical field of digital advanced manufacturing of aircrafts. The method comprises the steps of 1) recognizing topological adjacent performances of two surfaces; 2) classifying and recognizing bending arcs; 3) recognizing bending edge surfaces; the recognizing of the topological adjacent performances of two sides includes (1) defining of the topological adjacent performances of two sides, (2) first-stage classifying and recognizing, and (3) second-stage classifying and recognizing; the classifying and recognizing of bending arc include (1) classifying of the bending arc, and (2) recognizing of the bending arc. According to the method, the two topological surfaces are assumed to be generated by bending an original surface; the common side line of the two topological surface is the bending line, the topological adjacent performance of the two surfaces are defined according to the expression form of the bending line, and therefore, the automatic recognizing of the bending side characteristics can be achieved. With the adoption of the method, the recognizing of the bending side surface can be effectively achieved; the basis is provided for automatically calculating the key parameters of the bending side characteristics surface; therefore, the user interaction workload can be decreased, and the working efficiency can be really increased.
Description
Technical field
The present invention relates to Aircraft Sheet Metal Parts crimp characteristic recognition method.Can be to the curved of Aircraft Sheet Metal Parts using the method
Side feature quickly recognized, belongs to aircraft digital advanced manufacturing technology field.
Background technology
Crimp is characterized in that the folding surface of Aircraft Sheet Metal Parts, laminating position when being usually connected with other parts, due to
The complexity of aircaft configuration, so sheet metal part crimp feature is generally on-plane surface.
Currently, the design of domestic each Aviation Manufacturing Enterprises sheet metal part comes into digital times, but sheet metal part
The state that processing and manufacturing also rests on digital control processing with two methods of traditional handicraft and deposits, so in the blanking and inspection of sheet metal part
There is still a need for learning the key parameter of crimp feature during testing, especially typical angle, height, radius bend etc. are required for
It is labeled in the middle of three-dimensional feature tree and two-dimentional drawing, and mode of the mark of these parameters substantially also in man-machine interactively,
Need artificial cognition crimp feature, and carry out substantial amounts of interactively operation to calculate these parameters, process is loaded down with trivial details, inefficiency.
The content of the invention
To solve the above problems, the present invention provides a kind of Aircraft Sheet Metal Parts crimp feature identification based on topological adjacency
Method, the method assume that two manifold are produced after carrying out bending by an original face, and two manifold are jointly owned
Sideline is bending line, using the form of expression of bending line, defines the topological adjacency on two sides, and then realizes crimp feature
Automatic identification, the method are annotated and model design is with important practical value for Aircraft Sheet Metal Parts.
Crimp characteristic recognition method proposed by the present invention, two manifold for coming from Aircraft Sheet Metal Parts are by an original face
The analysis of the hypothesis and sheet metal process knowledge that generate after carrying out bending.
Concrete scheme is as follows：
A kind of sheet metal crimp characteristic recognition method based on topological adjacency, it is characterised in that comprise the steps：
1) two sides topological adjacency identification；2) classification of bending circular arc and identification；3) crimp face identification；
The step 1) identification of two sides topological adjacency, define comprising (1) two sides topological adjacency；(2) first-level class is known
Not；(3) secondary classification identification；
Described (1) two sides topological adjacency definition：Assume that two manifold are to carry out producing after bending by an original face
, by two manifold in the form of bending part, define two sides topological adjacency：Including first-level class, secondary classification；
Wherein, first-level class；
<1.1>Concave edge：On bending line, the tangent plane of any point is all on the inside of entity；
<1.2>Chimb：On bending line, the tangent plane of any point is all on the outside of entity；
<1.3>Trimming：On bending line, the tangent plane of any point is tangent with two manifold；
Wherein trimming type, can carry out secondary classification again by the concavity and convexity at the relative bending line of two manifold；
<2.1>Double flat trimming：On bending line, the tangent plane of any point is tangent with two manifold, and overlaps；
<2.2>Plano-concave trimming：On bending line, the tangent plane of any point is tangent with two manifold, and with a manifold weight
Close, tangent plane is on the inside of the entity of non-coincidence manifold；
<2.3>Plano-convex trimming：On bending line, the tangent plane of any point is tangent with two manifold, and with a manifold weight
Close, tangent plane is on the outside of the entity of non-coincidence manifold；
<2.4>Concavo-convex trimming：On bending line, the tangent plane of any point is tangent with two manifold, and misaligned with manifold,
Tangent plane on the inside of the entity of a manifold, on the outside of the entity of another manifold；
<2.5>Concave-concave trimming：On bending line, the tangent plane of any point is tangent with two manifold, and misaligned with manifold,
Tangent plane is on the inside of the entity of two manifold；
<2.6>Biconvex trimming：On bending line, the tangent plane of any point is tangent with two manifold, and misaligned with manifold,
Tangent plane is on the outside of the entity of two manifold；
Described (2) first-level class identification：Using the form of bending line, two sides topological adjacency is recognized, concrete grammar is：
1. two adjacent manifold F are obtained1、F2Common sideline, i.e. bending line, take sideline midpoint Pf；
2. midpoint P is obtained by CAA component application architectures built-in interfacefIn F1、F2In external normal vector V1And V2；
3. calculate bending line and belong to face F1When in midpoint PfPlace is anticlockwise to cut arrow Vt1, it is (square counterclockwise along bending line
To taking Pf(t0) point of proximity PΔf1(t0+ Δ t), Vt1=PΔf1(t0+Δt)-Pf(t0)), calculate bending line and belong to face F2Shi Zhong
Point PfPlace is anticlockwise to cut arrow Vt2, (counterclockwise P is taken along bending linef(t0) point of proximity PΔf2(t0+ Δ t), Vt2=
PΔf2(t0+Δt)-Pf(t0))；
4. calculate when bending line is belonging respectively to two manifold in midpoint PfWhen normal vector Vn1、Vn2；
Vn1=V1×Vt1 Vn2=V2×Vt2
5. two normal vector V are calculatedn1To Vn2With Vt1Be with reference to when angle theta counterclockwise, its process is：
A, acquisition Vn1To Vn2Cross product Vs, i.e. Vn1With Vn2Plane Ax+By+Cz+D=0 of composition, if VsWith Vt1Angle
More than 90 degree, by Vn1With Vn2Exchange；
B, by Vn1Coordinate along VsMove a certain distance, obtain the outer 1 point of P of planen1(x0,y0,z0)；
C, point Pn1Projection line equation to plane isIt is converted into parametric equation and obtains x=
x0- At, y=y0- Bt, z=z0- Ct, substitutes into plane equation and obtainsT is substituted into into projection line parameter
Equation is obtained Vn1Two-dimensional vector V planarn1', V is obtained in the same mannern2Two-dimensional vector V planarn2'；
D, extraction Vn1' coordinate (a, b), obtain Vn1' vertical vector Vn1”(b,-a)；
E, calculating Vn1' and Vn2' angle theta1If, θ1Equal to 180 degree, then θ=θ1；
F, otherwise calculate Vn1" and Vn2' angle theta2If, θ2Less than 90 degree, then θ=θ1+ 180, otherwise θ=θ1；
If θ is less than 180 degree, two sides topological adjacency form is concave edge；
If θ is more than 180 degree, two sides topological adjacency form is chimb；
If θ is equal to 180 degree, two sides topological adjacency form is tangent；
Described (3) secondary classification identification：On the basis of first-level class identification, retain external normal vector V1And V2Make
For the benchmark for further recognizing, obtain manifold midpoint and concave towards vector, and normal vector V external with two manifold respectively1And V2
Angle calcu-lation is carried out, is differentiated that concrete grammar is according to angle value：
If 1. topological adjacency form in two sides is tangent, normal vector V is recorded1For Vf1, V2For Vf2；
2. calculate bending line midpoint PfThe normal plane F at placef；
3. by normal plane FfRespectively with face F1、F2Friendship, acquisition is asked to seek knot fruit intersection L1、L2；
4. obtain intersection L1、L2Midpoint P1、P2；
5. calculate midpoint P1、P2Curvature C at place1、C2；
If 6. C1、C2Less than marginal value Q, Q values 1.0e+5, intersection is obtained by CAA component application architectures built-in interface
L1、L2Midpoint P1、P2The main method arrow V at placemn1、Vmn2；
7. vector V is calculated respectivelyf1With Vmn1Angle theta1, and Vf2With Vmn2Angle theta2；
8. contrasted according to curvature and angle, show that secondary classification recognition result is as follows：
If C1、C2Q is all higher than, then topological adjacency form in two sides is double flat trimming；
If C1More than Q, C2Less than Q, and θ2Less than 90 degree, then topological adjacency form in two sides is plano-concave trimming；
If C2More than Q, C1Less than Q, and θ1Less than 90 degree, then topological adjacency form in two sides is plano-concave trimming；
If C1More than Q, C2Less than Q, and θ2More than 90 degree, then topological adjacency form in two sides is plano-convex trimming；
If C2More than Q, C1Less than Q, and θ1More than 90 degree, then topological adjacency form in two sides is plano-convex trimming；
If C1、C2Respectively less than Q, and θ1More than 90 degree, θ2Less than 90 degree, then topological adjacency form in two sides is concavo-convex trimming；
If C1、C2Respectively less than Q, and θ1Less than 90 degree, θ2More than 90 degree, then topological adjacency form in two sides is concavo-convex trimming；
If C1、C2Respectively less than Q, and θ1、θ2Respectively less than 90 degree, then topological adjacency form in two sides is concave-concave trimming；
If C1、C2Respectively less than Q, and θ1、θ290 degree are all higher than, then topological adjacency form in two sides is biconvex trimming.
Described step 2) bending circular arc classification with identification, comprising (1) bending circular arc classify；(2) bending tool nose radius；
Described (1) bending circular arc classification：Bending circular arc is the transition arc between web surface and crimp face, is web surface
With the bridge between crimp face, two kinds of inner concave shape and male type can be divided into by the direction of bending；
Described (2) bending tool nose radius：By manifold F to be discriminateddpWith web surface FfbCarry out asking friendship, if it is successful, obtaining
The common bending line in two sides is taken, bending line midpoint P is takenf；Calculate midpoint PfIn face Fdp、FfbIn external normal vector VdpAnd Vfb；
Calculate bending line and belong to FdpWhen in midpoint PfPlace is anticlockwise to cut arrow Vtdp, calculate bending line and belong to FfbWhen in midpoint PfPlace
It is anticlockwise to cut arrow Vtfb；Calculate when bending line is belonging respectively to two manifold in midpoint PfThe normal vector V at placendp、Vnfb；
Calculate two normal vector VndpTo VnfbWith VtdpBe with reference to when angle theta counterclockwise, if θ be equal to 180 degree, it is to be discriminated to open up
Blow on one's face as bending circular arc；Calculate bending line midpoint PfThe normal plane F at placef；By FfWith FdpFriendship, acquisition is asked to seek knot fruit intersection Ldp；
Calculate LdpMidpoint PdpThe main method arrow V at placemndp；Calculate vector VdpWith VmndpAngle theta, if θ be less than 90 degree, bending circular arc
For inner concave shape；If θ is more than 90 degree, bending circular arc is male type.
Described step 3) identification of crimp face：By manifold F to be discriminateddpWith male type bending circular arc FzwCarry out asking friendship, such as
Fruit success, obtains the common bending line in two sides, takes bending line midpoint Pf；Calculate midpoint PfIn face Fdp、FzwIn external normal direction arrow
Amount VdpAnd Vzw；Calculate bending line and belong to FdpWhen in midpoint PfPlace is anticlockwise to cut arrow Vtdp, calculate bending line and belong to FzwWhen
In midpoint PfPlace is anticlockwise to cut arrow Vtzw；Calculate when bending line is belonging respectively to two manifold in midpoint PfThe normal vector at place
Vndp、Vnzw；Calculate two normal vector VndpTo VnzwWith VtdpBe with reference to when angle theta counterclockwise, if θ be equal to 180 degree,
Manifold to be discriminated is crimp face.
Beneficial effects of the present invention：The present invention is according to the identification of the topological adjacency of two adjacent surfaces, the shape to topological adjacency
Formula has done further expansion in detail, efficiently solves the identification in crimp face, is the key parameter for calculating automatically crimp characteristic face
There is provided foundation, so as to reduce user-interactive tasks amount, work efficiency is improve conscientiously.
Description of the drawings
Fig. 1 is Aircraft Sheet Metal Parts crimp feature schematic diagram.
Fig. 2 is two sides topological adjacency form calculus schematic diagram.
Fig. 3 is crimp feature identification general flow chart.
Fig. 4 is two sides topological adjacency first-level class identification process figure.
Fig. 5 is two sides topological adjacency secondary classification identification process figure.
Fig. 6 is two sides topological adjacency classification chart.
Fig. 7-1 to 7-9 is two sides topological adjacency form figure.
Specific embodiment
A kind of sheet metal crimp characteristic recognition method based on topological adjacency, comprises the steps：1) two face topological
Adjacency is recognized；2) classification of bending circular arc and identification；3) crimp face identification；(as shown in Figure 1)
The step 1) identification of two sides topological adjacency, define comprising (1) two sides topological adjacency；(2) first-level class is known
Not；(3) secondary classification identification；
Described (1) two sides topological adjacency definition：Assume that two manifold are to carry out producing after bending by an original face
, by two manifold in the form of bending part, define two sides topological adjacency：Including first-level class, secondary classification；(such as Fig. 6 institutes
Show)
Wherein, first-level class；
<1.1>Concave edge：On bending line, the tangent plane of any point is all on the inside of entity；As shown in Fig. 7-1；
<1.2>Chimb：On bending line, the tangent plane of any point is all on the outside of entity；As shown in Fig. 7-2；
<1.3>Trimming：On bending line, the tangent plane of any point is tangent with two manifold；As shown in Fig. 7-3；
Wherein trimming type, can carry out secondary classification again by the concavity and convexity at the relative bending line of two manifold；
<2.1>Double flat trimming：On bending line, the tangent plane of any point is tangent with two manifold, and overlaps；As Fig. 7-4 institute
Show；
<2.2>Plano-concave trimming：On bending line, the tangent plane of any point is tangent with two manifold, and with a manifold weight
Close, tangent plane is on the inside of the entity of non-coincidence manifold；As shown in Fig. 7-5；
<2.3>Plano-convex trimming：On bending line, the tangent plane of any point is tangent with two manifold, and with a manifold weight
Close, tangent plane is on the outside of the entity of non-coincidence manifold；As shown in Fig. 7-6；
<2.4>Concavo-convex trimming：On bending line, the tangent plane of any point is tangent with two manifold, and misaligned with manifold,
Tangent plane on the inside of the entity of a manifold, on the outside of the entity of another manifold；As shown in Fig. 7-7；
<2.5>Concave-concave trimming：On bending line, the tangent plane of any point is tangent with two manifold, and misaligned with manifold,
Tangent plane is on the inside of the entity of two manifold；As Figure 7-8；
<2.6>Biconvex trimming：On bending line, the tangent plane of any point is tangent with two manifold, and misaligned with manifold,
Tangent plane is on the outside of the entity of two manifold；As Figure 7-9；
Described (2) first-level class identification：Using the form of bending line, two sides topological adjacency is recognized, concrete grammar is：
(as shown in Figure 2)
1. two adjacent manifold F are obtained1、F2Common sideline, i.e. bending line, take sideline midpoint Pf；
2. midpoint P is obtained by CAA component application architectures built-in interfacefIn F1、F2In external normal vector V1And V2；
3. calculate bending line and belong to face F1When in midpoint PfPlace is anticlockwise to cut arrow Vt1, it is (square counterclockwise along bending line
To taking Pf(t0) point of proximity PΔf1(t0+ Δ t), Vt1=PΔf1(t0+Δt)-Pf(t0)), calculate bending line and belong to face F2Shi Zhong
Point PfPlace is anticlockwise to cut arrow Vt2, (counterclockwise P is taken along bending linef(t0) point of proximity PΔf2(t0+ Δ t), Vt2=
PΔf2(t0+Δt)-Pf(t0))；
4. calculate when bending line is belonging respectively to two manifold in midpoint PfWhen normal vector Vn1、Vn2；
Vn1=V1×Vt1 Vn2=V2×Vt2
5. two normal vector V are calculatedn1To Vn2With Vt1Be with reference to when angle theta counterclockwise, its process is：
A, acquisition Vn1To Vn2Cross product Vs, i.e. Vn1With Vn2Plane Ax+By+Cz+D=0 of composition, if VsWith Vt1Angle
More than 90 degree, by Vn1With Vn2Exchange；
B, by Vn1Coordinate along VsMove a certain distance, obtain the outer 1 point of P of planen1(x0,y0,z0)；
C, point Pn1Projection line equation to plane isIt is converted into parametric equation and obtains x=
x0- At, y=y0- Bt, z=z0- Ct, substitutes into plane equation and obtainsT is substituted into into projection line parameter
Equation is obtained Vn1Two-dimensional vector V planarn1', V is obtained in the same mannern2Two-dimensional vector V planarn2'；
D, extraction Vn1' coordinate (a, b), obtain Vn1' vertical vector Vn1”(b,-a)；
E, calculating Vn1' and Vn2' angle theta1If, θ1Equal to 180 degree, then θ=θ1；
F, otherwise calculate Vn1" and Vn2' angle theta2If, θ2Less than 90 degree, then θ=θ1+ 180, otherwise θ=θ1；
If θ is less than 180 degree, two sides topological adjacency form is concave edge；
If θ is more than 180 degree, two sides topological adjacency form is chimb；
If θ is equal to 180 degree, two sides topological adjacency form is tangent；
Described (3) secondary classification identification：On the basis of first-level class identification, retain external normal vector V1And V2Make
For the benchmark for further recognizing, obtain manifold midpoint and concave towards vector, and normal vector V external with two manifold respectively1And V2
Angle calcu-lation is carried out, is differentiated that concrete grammar is according to angle value：
If 1. topological adjacency form in two sides is tangent, normal vector V is recorded1For Vf1, V2For Vf2；
2. calculate bending line midpoint PfThe normal plane F at placef；
3. by normal plane FfRespectively with face F1、F2Friendship, acquisition is asked to seek knot fruit intersection L1、L2；
4. obtain intersection L1、L2Midpoint P1、P2；
5. calculate midpoint P1、P2Curvature C at place1、C2；
If 6. C1、C2Less than marginal value Q, Q values 1.0e+5, intersection is obtained by CAA component application architectures built-in interface
L1、L2Midpoint P1、P2The main method arrow V at placemn1、Vmn2；
7. vector V is calculated respectivelyf1With Vmn1Angle theta1, and Vf2With Vmn2Angle theta2；
8. contrasted according to curvature and angle, show that secondary classification recognition result is as follows：
If C1、C2Q is all higher than, then topological adjacency form in two sides is double flat trimming；
If C1More than Q, C2Less than Q, and θ2Less than 90 degree, then topological adjacency form in two sides is plano-concave trimming；
If C2More than Q, C1Less than Q, and θ1Less than 90 degree, then topological adjacency form in two sides is plano-concave trimming；
If C1More than Q, C2Less than Q, and θ2More than 90 degree, then topological adjacency form in two sides is plano-convex trimming；
If C2More than Q, C1Less than Q, and θ1More than 90 degree, then topological adjacency form in two sides is plano-convex trimming；
If C1、C2Respectively less than Q, and θ1More than 90 degree, θ2Less than 90 degree, then topological adjacency form in two sides is concavo-convex trimming；
If C1、C2Respectively less than Q, and θ1Less than 90 degree, θ2More than 90 degree, then topological adjacency form in two sides is concavo-convex trimming；
If C1、C2Respectively less than Q, and θ1、θ2Respectively less than 90 degree, then topological adjacency form in two sides is concave-concave trimming；
If C1、C2Respectively less than Q, and θ1、θ290 degree are all higher than, then topological adjacency form in two sides is biconvex trimming.
Described step 2) bending circular arc classification with identification, comprising (1) bending circular arc classify；(2) bending tool nose radius；
Described (1) bending circular arc classification：Bending circular arc is the transition arc between web surface and crimp face, is web surface
With the bridge between crimp face, two kinds of inner concave shape and male type can be divided into by the direction of bending；
Described (2) bending tool nose radius：By manifold F to be discriminateddpWith web surface FfbCarry out asking friendship, if it is successful, obtaining
The common bending line in two sides is taken, bending line midpoint P is takenf；Calculate midpoint PfIn face Fdp、FfbIn external normal vector VdpAnd Vfb；
Calculate bending line and belong to FdpWhen in midpoint PfPlace is anticlockwise to cut arrow Vtdp, calculate bending line and belong to FfbWhen in midpoint PfPlace
It is anticlockwise to cut arrow Vtfb；Calculate when bending line is belonging respectively to two manifold in midpoint PfThe normal vector V at placendp、Vnfb；
Calculate two normal vector VndpTo VnfbWith VtdpBe with reference to when angle theta counterclockwise, if θ be equal to 180 degree, it is to be discriminated to open up
Blow on one's face as bending circular arc；Calculate bending line midpoint PfThe normal plane F at placef；By FfWith FdpFriendship, acquisition is asked to seek knot fruit intersection Ldp；
Calculate LdpMidpoint PdpThe main method arrow V at placemndp；Calculate vector VdpWith VmndpAngle theta, if θ be less than 90 degree, bending circular arc
For inner concave shape；If θ is more than 90 degree, bending circular arc is male type.
Described step 3) identification of crimp face：By manifold F to be discriminateddpWith male type bending circular arc FzwCarry out asking friendship, such as
Fruit success, obtains the common bending line in two sides, takes bending line midpoint Pf；Calculate midpoint PfIn face Fdp、FzwIn external normal direction arrow
Amount VdpAnd Vzw；Calculate bending line and belong to FdpWhen in midpoint PfPlace is anticlockwise to cut arrow Vtdp, calculate bending line and belong to FzwWhen
In midpoint PfPlace is anticlockwise to cut arrow Vtzw；Calculate when bending line is belonging respectively to two manifold in midpoint PfThe normal vector at place
Vndp、Vnzw；Calculate two normal vector VndpTo VnzwWith VtdpBe with reference to when angle theta counterclockwise, if θ be equal to 180 degree,
Manifold to be discriminated is crimp face.
Application example：
This example be premised on preceding solution under carry out.
Fig. 3 show the idiographic flow of Aircraft Sheet Metal Parts crimp characteristic recognition method proposed by the present invention, and which realizes step
It is rapid in order to：1) load web surface (S1)；2) web surface adjacent side and proximal surface (S2) are extracted；3) recognize male type bending circular arc (S3)；
4) bending circular arc adjacent side and proximal surface (S4) are extracted；5) crimp face identification (S5)；Wherein：
Described step 1) loading web surface (S1), i.e., the manifold as web surface is chosen in the model space；
Step 2) extract web surface adjacent side and proximal surface (S2), i.e., the successful manifold of friendship is sought in the model space with web surface
For web adjacent surface, adjacent surface is bending line with the co-owned sideline of web surface；
Step 3) identification male type bending circular arc (S3), that is, differentiate that web surface is phase with the topological adjacency mode of its proximal surface
Cut, and proximal surface type is convex, concrete grammar is：
(1) recognize whether two sides topological adjacency mode is tangent (as shown in Figure 4)：Manifold F to be discriminated is obtained first1、
With web surface F2Common bending line, takes bending line midpoint Pf(S6)；Calculate midpoint PfIn face F1、F2In external normal vector V1
And V2(S7)；Calculate bending line and belong to face F1When in midpoint PfPlace is anticlockwise to cut arrow Vt1, calculate bending line and belong to face F2When
In midpoint PfPlace is anticlockwise to cut arrow Vt2(S8)；Calculate when bending line is belonging respectively to two manifold in midpoint PfWhen normal direction
Vector Vn1、Vn2(S9)；Calculate two normal vector Vn1To Vn2With Vt1Be with reference to when angle theta counterclockwise (S10), if θ etc.
In 180 degree, then manifold to be discriminated is bending circular arc (S11), is retained, is further recognized；
(2) recognize whether proximal surface type is convex (as shown in Figure 5)：Record normal vector V1For Vf1, V2For Vf2(S12)；Meter
Calculate bending line midpoint PfThe normal plane F at placef(S13)；By normal plane FfRespectively with face F1、F2Friendship, acquisition is asked to seek knot fruit intersection L1、
L2(S14)；Calculate L1、L2Midpoint P1、P2；Calculate midpoint P1、P2Curvature C at place1、C2(S15)；If C1、C2More than marginal value
Q, then F1、F2Face is flat type (S16), otherwise calculates intersection L1、L2Midpoint P1、P2The main method arrow V at placemn1、Vmn2(S17)；Point
Ji Suan not vector Vf1With Vmn1, Vf2With Vmn2Angle, if angle be more than 90 degree, this manifold for male type bending circle
Arc (S19)；
Step 4) obtain bending circular arc adjacent side and proximal surface (S4), i.e., in the model space, ask friendship successfully to open up with bending circular arc
Blow on one's face, and be not web surface i.e. bending circular arc proximal surface, proximal surface is bending line with the co-owned sideline of bending circular arc；
Step 5) crimp face identification (S5), that is, differentiate whether bending circular arc is tangent, side with its proximal surface topological adjacency mode
Method is：Manifold F to be discriminated is obtained first1, and bending circular arc F2Common bending line, takes bending line midpoint Pf(S6)；In calculating
Point PfIn face F1、F2In external normal vector V1And V2(S7)；Calculate bending line and belong to face F1When in midpoint PfPlace is square counterclockwise
To cut arrow Vt1, calculate bending line and belong to face F2When in midpoint PfPlace is anticlockwise to cut arrow Vt2(S8)；Calculate bending line point
In midpoint P when not belonging to two manifoldfWhen normal vector Vn1、Vn2(S9)；Calculate two normal vector Vn1To Vn2With Vt1For ginseng
Angle theta counterclockwise (S10) when examining, if θ is equal to 180 degree, manifold to be discriminated is crimp face (S11).
Claims (3)
1. a kind of sheet metal crimp characteristic recognition method based on topological adjacency, it is characterised in that comprise the steps：1)
Two sides topological adjacency identification；2) classification of bending circular arc and identification；3) crimp face identification；
The step 1) identification of two sides topological adjacency, define comprising (1) two sides topological adjacency；(2) first-level class identification；
(3) secondary classification identification；
Described (1) two sides topological adjacency definition：Assume that two manifold are produced after bending being carried out by an original face, press
Form of two manifold in bending part, defines two sides topological adjacency：Including first-level class, secondary classification；
Wherein, first-level class；
<1.1>Concave edge：On bending line, the tangent plane of any point is all on the inside of entity；
<1.2>Chimb：On bending line, the tangent plane of any point is all on the outside of entity；
<1.3>Trimming：On bending line, the tangent plane of any point is tangent with two manifold；
Wherein trimming type, can carry out secondary classification again by the concavity and convexity at the relative bending line of two manifold；
<2.1>Double flat trimming：On bending line, the tangent plane of any point is tangent with two manifold, and overlaps；
<2.2>Plano-concave trimming：On bending line, the tangent plane of any point is tangent with two manifold, and overlaps with a manifold, cuts
Face is on the inside of the entity of non-coincidence manifold；
<2.3>Plano-convex trimming：On bending line, the tangent plane of any point is tangent with two manifold, and overlaps with a manifold, cuts
Face is on the outside of the entity of non-coincidence manifold；
<2.4>Concavo-convex trimming：On bending line, the tangent plane of any point is tangent with two manifold, and misaligned with manifold, tangent plane
On the inside of the entity of a manifold, on the outside of the entity of another manifold；
<2.5>Concave-concave trimming：On bending line, the tangent plane of any point is tangent with two manifold, and misaligned with manifold, tangent plane
On the inside of the entity of two manifold；
<2.6>Biconvex trimming：On bending line, the tangent plane of any point is tangent with two manifold, and misaligned with manifold, tangent plane
On the outside of the entity of two manifold；
Described (2) first-level class identification：Using the form of bending line, two sides topological adjacency is recognized, concrete grammar is：
1. two adjacent manifold F are obtained1、F2Common sideline, i.e. bending line, take sideline midpoint Pf；
2. midpoint P is obtained by CAA component application architectures built-in interfacefIn F1、F2In external normal vector V1And V2；
3. calculate bending line and belong to face F1When in midpoint PfPlace is anticlockwise to cut arrow Vt1, counterclockwise P is taken along bending linef
(t0) point of proximity PΔf1(t0+ Δ t), Vt1=PΔf1(t0+Δt)-Pf(t0), calculate bending line and belong to face F2When in midpoint PfPlace
It is anticlockwise to cut arrow Vt2, counterclockwise P is taken along bending linef(t0) point of proximity PΔf2(t0+ Δ t), Vt2=PΔf2(t0+
Δt)-Pf(t0)；
4. calculate when bending line is belonging respectively to two manifold in midpoint PfWhen normal vector Vn1、Vn2；
Vn1=V1×Vt1 Vn2=V2×Vt2
5. two normal vector V are calculatedn1To Vn2With Vt1Be with reference to when angle theta counterclockwise, its process is：
A, acquisition Vn1To Vn2Cross product Vs, i.e. Vn1With Vn2Plane Ax+By+Cz+D=0 of composition, if VsWith Vt1Angle is more than
90 degree, by Vn1With Vn2Exchange；
B, by Vn1Coordinate along VsMove a certain distance, obtain the outer 1 point of P of planen1(x0,y0,z0)；
C, point Pn1Projection line equation to plane isIt is converted into parametric equation and obtains x=x0- At,
Y=y0- Bt, z=z0- Ct, substitutes into plane equation and obtainsBy t substitution projection line parametric equations it is
V is obtainedn1Two-dimensional vector V planarn1', V is obtained in the same mannern2Two-dimensional vector V planarn2'；
D, extraction Vn1' coordinate (a, b), obtain Vn1' vertical vector Vn1”(b,-a)；
E, calculating Vn1' and Vn2' angle theta1If, θ1Equal to 180 degree, then θ=θ1；
F, otherwise calculate Vn1" and Vn2' angle theta2If, θ2Less than 90 degree, then θ=θ1+ 180, otherwise θ=θ1；
If θ is less than 180 degree, two sides topological adjacency form is concave edge；
If θ is more than 180 degree, two sides topological adjacency form is chimb；
If θ is equal to 180 degree, two sides topological adjacency form is tangent；
Described (3) secondary classification identification：On the basis of first-level class identification, retain external normal vector V1And V2As entering
The benchmark of one step identification, obtains manifold midpoint and concaves towards vector, and normal vector V external with two manifold respectively1And V2Carry out
According to angle value, angle calcu-lation, is differentiated that concrete grammar is：
If 1. topological adjacency form in two sides is tangent, normal vector V is recorded1For Vf1, V2For Vf2；
2. calculate bending line midpoint PfThe normal plane F at placef；
3. by normal plane FfRespectively with face F1、F2Friendship, acquisition is asked to seek knot fruit intersection L1、L2；
4. obtain intersection L1、L2Midpoint P1、P2；
5. calculate midpoint P1、P2Curvature C at place1、C2；
If 6. C1、C2Less than marginal value Q, Q values 1.0e+5, intersection L is obtained by CAA component application architectures built-in interface1、L2
Midpoint P1、P2The main method arrow V at placemn1、Vmn2；
7. vector V is calculated respectivelyf1With Vmn1Angle theta1, and Vf2With Vmn2Angle theta2；
8. contrasted according to curvature and angle, show that secondary classification recognition result is as follows：
If C1、C2Q is all higher than, then topological adjacency form in two sides is double flat trimming；
If C1More than Q, C2Less than Q, and θ2Less than 90 degree, then topological adjacency form in two sides is plano-concave trimming；
If C2More than Q, C1Less than Q, and θ1Less than 90 degree, then topological adjacency form in two sides is plano-concave trimming；
If C1More than Q, C2Less than Q, and θ2More than 90 degree, then topological adjacency form in two sides is plano-convex trimming；
If C2More than Q, C1Less than Q, and θ1More than 90 degree, then topological adjacency form in two sides is plano-convex trimming；
If C1、C2Respectively less than Q, and θ1More than 90 degree, θ2Less than 90 degree, then topological adjacency form in two sides is concavo-convex trimming；
If C1、C2Respectively less than Q, and θ1Less than 90 degree, θ2More than 90 degree, then topological adjacency form in two sides is concavo-convex trimming；
If C1、C2Respectively less than Q, and θ1、θ2Respectively less than 90 degree, then topological adjacency form in two sides is concave-concave trimming；
If C1、C2Respectively less than Q, and θ1、θ290 degree are all higher than, then topological adjacency form in two sides is biconvex trimming.
2. a kind of sheet metal crimp characteristic recognition method based on topological adjacency according to claim 1, its feature
Be, described step 2) bending circular arc classification with identification, comprising (1) bending circular arc classify；(2) bending tool nose radius；
Described (1) bending circular arc classification：Bending circular arc is the transition arc between web surface and crimp face, be web surface with it is curved
Bridge between the face of side, can be divided into two kinds of inner concave shape and male type by the direction of bending；
Described (2) bending tool nose radius：By manifold F to be discriminateddpWith web surface FfbCarry out asking friendship, if it is successful, obtaining two
The common bending line in face, takes bending line midpoint Pf；Calculate midpoint PfIn face Fdp、FfbIn external normal vector VdpAnd Vfb；Calculate
Bending line belongs to FdpWhen in midpoint PfPlace is anticlockwise to cut arrow Vtdp, calculate bending line and belong to FfbWhen in midpoint PfPlace's inverse time
V is sweared in cutting for pin directiontfb；Calculate when bending line is belonging respectively to two manifold in midpoint PfThe normal vector V at placendp、Vnfb；Calculate
Two normal vector VndpTo VnfbWith VtdpBe with reference to when angle theta counterclockwise, if θ be equal to 180 degree, manifold to be discriminated
For bending circular arc；Calculate bending line midpoint PfThe normal plane F at placef；By FfWith FdpFriendship, acquisition is asked to seek knot fruit intersection Ldp；Calculate
LdpMidpoint PdpThe main method arrow V at placemndp；Calculate vector VdpWith VmndpAngle theta, if θ be less than 90 degree, bending circular arc be it is interior
Matrix；If θ is more than 90 degree, bending circular arc is male type.
3. a kind of sheet metal crimp characteristic recognition method based on topological adjacency according to claim 1, its feature
It is, described step 3) identification of crimp face：By manifold F to be discriminateddpWith male type bending circular arc FzwCarry out asking friendship, if
Success, obtains the common bending line in two sides, takes bending line midpoint Pf；Calculate midpoint PfIn face Fdp、FzwIn external normal vector
VdpAnd Vzw；Calculate bending line and belong to FdpWhen in midpoint PfPlace is anticlockwise to cut arrow Vtdp, calculate bending line and belong to FzwShi
Midpoint PfPlace is anticlockwise to cut arrow Vtzw；Calculate when bending line is belonging respectively to two in midpoint PfThe normal vector V at placendp、Vnzw；
Calculate two normal vector VndpTo VnzwWith VtdpBe with reference to when angle theta counterclockwise, if θ be equal to 180 degree, it is to be discriminated to open up
Blow on one's face as crimp face.
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