CN104615078A - Method for recognizing characteristics of bending side of aircraft sheet metal based on topological adjacent performance - Google Patents

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

Based on the sheet metal crimp characteristic recognition method of topological adjacency

Technical field

The present invention relates to Aircraft Sheet Metal Parts crimp characteristic recognition method.Adopt the method can identify fast the crimp feature of Aircraft Sheet Metal Parts, belong to aircraft digital advanced manufacturing technology field.

Background technology

Crimp feature is the folding surface of Aircraft Sheet Metal Parts, is generally laminating position when being connected with other part, due to the complicacy of aircaft configuration, so sheet metal part crimp feature is generally on-plane surface.

Current, the design of domestic each Aviation Manufacturing Enterprises sheet metal part enters digital times, but the processing and manufacturing of sheet metal part also rests on digital control processing and traditional handicraft two kinds of methods and the state of depositing, still the key parameter learning crimp feature is needed like this in the blanking and checkout procedure of sheet metal part, especially typical angle, highly, radius bend etc. all need to mark in the middle of three-dimensional feature tree and two-dimentional drawing, and the mark of these parameters is substantially also in the mode of man-machine interactively, need artificial cognition crimp feature, and carry out a large amount of interactively these parameters of operation calculating, process is loaded down with trivial details, inefficiency.

Summary of the invention

For solving the problem, the invention provides a kind of Aircraft Sheet Metal Parts crimp characteristic recognition method based on topological adjacency, the method supposes that two manifold produce after carrying out bending by an original face, the sideline that two manifold are owned together is bending line, utilize the form of expression of bending line, the connecing property of topology neck on definition two sides, and then achieves the automatic identification of crimp feature, and the method carries out annotating for Aircraft Sheet Metal Parts and model design has important practical value.

The crimp characteristic recognition method that the present invention proposes, two manifold coming from Aircraft Sheet Metal Parts are the analyses of hypothesis and the sheet metal process knowledge generated after carrying out bending by an original face.

Concrete scheme is as follows:

Based on a sheet metal crimp characteristic recognition method for topological adjacency, it is characterized in that, comprise the steps: 1) two sides topological adjacency identification; 2) classification of bending circular arc and identification; 3) crimp face identifies;

Described step 1) two sides topological adjacency identification, comprise the topological adjacency definition of (1) two sides; (2) first-level class identification; (3) secondary classification identification;

Described (1) two sides topological adjacency definition: suppose that two manifold produce after carrying out bending by an original face, by the form of two manifold at bending part, definition two sides topological adjacency: comprise first-level class, secondary classification;

Wherein, first-level class;

<1.1> concave edge: on bending line, the tangent plane of any point is all inside entity;

<1.2> chimb: on bending line, the tangent plane of any point is all outside entity;

<1.3> trimming: on bending line the tangent plane of any point and two manifold tangent;

Wherein trimming type, can carry out secondary classification again by the concavity and convexity at the two relative bending line places of manifold;

The two truncation limit of <2.1>: on bending line, the tangent plane of any point is tangent with two manifold, and coincidence;

The trimming of <2.2> plano-concave: on bending line the tangent plane of any point and two manifold tangent, and overlap with a manifold, tangent plane is inside the entity of non-coincidence manifold;

The trimming of <2.3> plano-convex: on bending line the tangent plane of any point and two manifold tangent, and overlap with a manifold, tangent plane is outside the entity of non-coincidence manifold;

The concavo-convex trimming of <2.4>: on bending line the tangent plane of any point and two manifold tangent, and not overlap with manifold, tangent plane inside the entity of a manifold, outside the entity of another manifold;

The trimming of <2.5> concave-concave: on bending line the tangent plane of any point and two manifold tangent, and do not overlap with manifold, tangent plane is inside the entity of two manifold;

The trimming of <2.6> concave-concave: on bending line the tangent plane of any point and two manifold tangent, and do not overlap with manifold, tangent plane is outside the entity of two manifold;

Described (2) first-level class identification: the form utilizing bending line, identify two sides topological adjacency, concrete grammar is:

1. two adjacent manifold F are obtained ₁, F ₂common sideline, i.e. bending line, get sideline mid point P _f;

2. mid point P is obtained by CAA component application framework built-in interface _fat F ₁, F ₂in in vitro method to vector V ₁and V ₂;

3. calculate bending line and belong to face F ₁time at mid point P _flocate anticlockwise cutting and vow V _t1, (counterclockwise get P along bending line _f(t ₀) point of proximity P _{Δ f1}(t ₀+ Δ t), V _t1=P _{Δ f1}(t ₀+ Δ t)-P _f(t ₀)), calculate bending line and belong to face F ₂time at mid point P _flocate anticlockwise cutting and vow V _t2, (counterclockwise get P along bending line _f(t ₀) point of proximity P _{Δ f2}(t ₀+ Δ t), V _t2=P _{Δ f2}(t ₀+ Δ t)-P _f(t ₀));

4. calculate when bending line belongs to two manifold respectively at mid point P _ftime normal vector V _n1, V _n2;

V _n1＝V ₁×V _t1V _n2＝V ₂×V _t2

5. two normal vector V are calculated _n1to V _n2with V _t1for counterclockwise angle theta during reference, its process is:

A, acquisition V _n1to V _n2cross product V _s, i.e. V _n1with V _n2the plane Ax+By+Cz+D=0 formed, if V _swith V _t1angle is greater than 90 degree, by V _n1with V _n2exchange;

B, by V _n1coordinate along V _smove a certain distance, obtain outer 1 P of plane _n1(x ₀, y ₀, z ₀);

C, some P _n1projection line equation to plane is $\frac{x_0-x}{A}=\frac{y_0-y}{B}=\frac{z_0-z}{C}=t,$ Be converted into parametric equation and obtain x=x ₀-At, y=y ₀-Bt, z=z ₀-Ct, substitutes into plane equation and obtains t is substituted into projection line parametric equation and can obtain V _n1two-dimensional vector V planar _n1', in like manner obtain V _n2two-dimensional vector V planar _n2';

D, extraction V _n1' coordinate (a, b), obtain V _n1' vertical vector V _n1" (b ,-a);

E, calculating V _n1' and V _n2' angle theta ₁if, θ ₁equal 180 degree, so θ=θ ₁; 6 otherwise calculate V _n1" and V _n2' angle theta ₂if, θ ₂be less than 90 degree, so θ=θ ₁+ 180, otherwise θ=θ ₁;

If θ is less than 180 degree, then topological adjacency form in two sides is concave edge;

If θ is greater than 180 degree, then topological adjacency form in two sides is chimb;

If θ equals 180 degree, then topological adjacency form in two sides is tangent;

Described (3) secondary classification identification: on the basis of first-level class identification, the outer normal vector V of retention body ₁and V ₂as the benchmark identified further, obtain manifold midpoint recessed to vector, and external to vector V with two manifold respectively ₁and V ₂carry out angle calcu-lation, differentiate according to angle value, concrete grammar is:

If 1. topological adjacency form in two sides is tangent, writing-method is to vector V ₁for V _f1, V ₂for V _f2;

2. bending line mid point P is calculated _fthe normal plane F at place _f;

3. by normal plane F _frespectively with face F ₁, F ₂ask friendship, obtain and ask knot fruit intersection L ₁, L ₂;

4. intersection L is obtained ₁, L ₂mid point P ₁, P ₂;

5. mid point P is calculated ₁, P ₂the curvature C at place ₁, C ₂;

If 6. C ₁, C ₂be less than critical value Q, Q value 1.0e+5, obtain intersection L by CAA component application framework built-in interface ₁, L ₂mid point P ₁, P ₂the main method at place vows V _mn1, V _mn2;

7. compute vectors V is distinguished _f1with V _mn1angle theta ₁, and V _f2with V _mn2angle theta ₂;

$\begin{array}{cc}\cos \left({\mathrm{\&theta;}}_1\right)=\frac{|v_{f1}\&CenterDot;v_{\mathrm{mn}1}|}{\left|v_{f1}\right|\left|v_{\mathrm{mn}1}\right|}& \cos \left({\mathrm{\&theta;}}_2\right)=\frac{|v_{f2}\&CenterDot;v_{\mathrm{mn}2}|}{\left|v_{f2}\right|\left|v_{\mathrm{mn}2}\right|}\end{array}$

8. according to curvature and angle contrast, show that secondary classification recognition result is as follows:

If C ₁, C ₂all be greater than Q, then topological adjacency form in two sides is two truncation limits;

If C ₁be greater than Q, C ₂be less than Q, and θ ₂be less than 90 degree, then topological adjacency form in two sides is plano-concave trimming;

If C ₂be greater than Q, C ₁be less than Q, and θ ₁be less than 90 degree, then topological adjacency form in two sides is plano-concave trimming;

If C ₁be greater than Q, C ₂be less than Q, and θ ₂be greater than 90 degree, then topological adjacency form in two sides is plano-convex trimming;

If C ₂be greater than Q, C ₁be less than Q, and θ ₁be greater than 90 degree, then topological adjacency form in two sides is plano-convex trimming;

If C ₁, C ₂all be less than Q, and θ ₁be greater than 90 degree, θ ₂be less than 90 degree, then topological adjacency form in two sides is concavo-convex trimming;

If C ₁, C ₂all be less than Q, and θ ₁be less than 90 degree, θ ₂be greater than 90 degree, then topological adjacency form in two sides is concavo-convex trimming;

If C ₁, C ₂all be less than Q, and θ ₁, θ ₂all be less than 90 degree, then topological adjacency form in two sides is concave-concave trimming;

If C ₁, C ₂all be less than Q, and θ ₁, θ ₂all be greater than 90 degree, then topological adjacency form in two sides is biconvex trimming.

Described step 2) bending circular arc classification with identify, comprise (1) bending circular arc classification; (2) bending tool nose radius;

Described (1) bending circular arc classification: bending circular arc and the transition arc between web surface and crimp face are the bridges between web surface and crimp face, can be divided into inner concave shape and male type two kinds by bending direction;

Described (2) bending tool nose radius: by manifold F to be discriminated _dpwith web surface F _fbcarry out asking friendship, if success, obtain the bending line that two sides is common, get bending line mid point P _f; Calculate mid point P _fat face F _dp, F _fbin in vitro method to vector V _dpand V _fb; Calculate bending line and belong to F _dptime at mid point P _flocate anticlockwise cutting and vow V _tdp, calculate bending line and belong to F _fbtime at mid point P _flocate anticlockwise cutting and vow V _tfb; Calculate when bending line belongs to two respectively at mid point P _fthe normal vector V at place _ndp, V _nfb; Calculate two normal vector V _ndpto V _nfbwith V _tdpfor counterclockwise angle theta during reference, if θ equals 180 degree, then manifold to be discriminated is bending circular arc; Calculate bending line mid point P _fthe normal plane F at place _f; By F _fwith F _dpask friendship, obtain and ask knot fruit intersection L _dp; Calculate L _dpmid point P _dpthe main method at place vows V _mndp; Compute vectors V _dpwith V _mndpangle theta, if θ is less than 90 degree, then bending circular arc is inner concave shape; If θ is greater than 90 degree, then bending circular arc is male type.

Described step (3) crimp face identifies: by manifold F to be discriminated _dpwith male type bending circular arc F _zwcarry out asking friendship, if success, obtain the bending line that two sides is common, get bending line mid point P _f; Calculate mid point P _fat face F _dp, F _zwin in vitro method to vector V _dpand V _zw; Calculate bending line and belong to F _dptime at mid point P _flocate anticlockwise cutting and vow V _tdp, calculate bending line and belong to F _zwtime at mid point P _flocate anticlockwise cutting and vow V _tzw; Calculate when bending line belongs to two respectively at mid point P _fthe normal vector V at place _ndp, V _nzw; Calculate two normal vector V _ndpto V _nzwwith V _tdpfor counterclockwise angle theta during reference, if θ equals 180 degree, then manifold to be discriminated is crimp face.

Beneficial effect of the present invention: the present invention is according to the topological adjacency identification of two adjacent surfaces, the form of topological adjacency is done and has further expanded in detail, efficiently solve the identification in crimp face, for the key parameter automatically calculating crimp characteristic face provides foundation, thus decrease user-interactive tasks amount, conscientiously improve work efficiency.

Accompanying drawing explanation

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.

Embodiment

Based on a sheet metal crimp characteristic recognition method for topological adjacency, comprise the steps: 1) two sides topological adjacency identification; 2) classification of bending circular arc and identification; 3) crimp face identifies; (as shown in Figure 1)

Described step 1) two sides topological adjacency identification, comprise the topological adjacency definition of (1) two sides; (2) first-level class identification; (3) secondary classification identification;

Described (1) two sides topological adjacency definition: suppose that two manifold produce after carrying out bending by an original face, by the form of two manifold at bending part, definition two sides topological adjacency: comprise first-level class, secondary classification; (as shown in Figure 6)

Wherein, first-level class;

<1.1> concave edge: on bending line, the tangent plane of any point is all inside entity; As shown in Fig. 7-1;

<1.2> chimb: on bending line, the tangent plane of any point is all outside entity; As shown in Fig. 7-2;

<1.3> trimming: on bending line the tangent plane of any point and two manifold tangent; As shown in Fig. 7-3;

Wherein trimming type, can carry out secondary classification again by the concavity and convexity at the two relative bending line places of manifold;

The two truncation limit of <2.1>: on bending line, the tangent plane of any point is tangent with two manifold, and coincidence; As shown in Fig. 7-4;

The trimming of <2.2> plano-concave: on bending line the tangent plane of any point and two manifold tangent, and overlap with a manifold, tangent plane is inside the entity of non-coincidence manifold; As shown in Fig. 7-5;

The trimming of <2.3> plano-convex: on bending line the tangent plane of any point and two manifold tangent, and overlap with a manifold, tangent plane is outside the entity of non-coincidence manifold; As shown in Fig. 7-6;

The concavo-convex trimming of <2.4>: on bending line the tangent plane of any point and two manifold tangent, and not overlap with manifold, tangent plane inside the entity of a manifold, outside the entity of another manifold; As shown in Fig. 7-7;

The trimming of <2.5> concave-concave: on bending line the tangent plane of any point and two manifold tangent, and do not overlap with manifold, tangent plane is inside the entity of two manifold; As Figure 7-8;

The trimming of <2.6> concave-concave: on bending line the tangent plane of any point and two manifold tangent, and do not overlap with manifold, tangent plane is outside the entity of two manifold; As Figure 7-9;

Described (2) first-level class identification: the form utilizing bending line, identify two sides topological adjacency, concrete grammar is: (as shown in Figure 2)

1. two adjacent manifold F are obtained ₁, F ₂common sideline, i.e. bending line, get sideline mid point P _f;

2. mid point P is obtained by CAA component application framework built-in interface _fat F ₁, F ₂in in vitro method to vector V ₁and V ₂;

3. calculate bending line and belong to face F ₁time at mid point P _flocate anticlockwise cutting and vow V _t1, (counterclockwise get P along bending line _f(t ₀) point of proximity P _{Δ f1}(t ₀+ Δ t), V _t1=P _{Δ f1}(t ₀+ Δ t)-P _f(t ₀)), calculate bending line and belong to face F ₂time at mid point P _flocate anticlockwise cutting and vow V _t2, (counterclockwise get P along bending line _f(t ₀) point of proximity P _{Δ f2}(t ₀+ Δ t), V _t2=P _{Δ f2}(t ₀+ Δ t)-P _f(t ₀));

4. calculate when bending line belongs to two manifold respectively at mid point P _ftime normal vector V _n1, V _n2;

V _n1＝V ₁×V _t1V _n2＝V ₂×V _t2

5. two normal vector V are calculated _n1to V _n2with V _t1for counterclockwise angle theta during reference, its process is:

A, acquisition V _n1to V _n2cross product V _s, i.e. V _n1with V _n2the plane Ax+By+Cz+D=0 formed, if V _swith V _t1angle is greater than 90 degree, by V _n1with V _n2exchange;

B, by V _n1coordinate along V _smove a certain distance, obtain outer 1 P of plane _n1(x ₀, y ₀, z ₀);

C, some P _n1projection line equation to plane is $\frac{x_0-x}{A}=\frac{y_0-y}{B}=\frac{z_0-z}{C}=t,$ Be converted into parametric equation and obtain x=x ₀-At, y=y ₀-Bt, z=z ₀-Ct, substitutes into plane equation and obtains t is substituted into projection line parametric equation and can obtain V _n1two-dimensional vector V planar _n1', in like manner obtain V _n2two-dimensional vector V planar _n2';

D, extraction V _n1' coordinate (a, b), obtain V _n1' vertical vector V _n1" (b ,-a);

E, calculating V _n1' and V _n2' angle theta ₁if, θ ₁equal 180 degree, so θ=θ ₁; 6 otherwise calculate V _n1" and V _n2' angle theta ₂if, θ ₂be less than 90 degree, so θ=θ ₁+ 180, otherwise θ=θ ₁;

If θ is less than 180 degree, then topological adjacency form in two sides is concave edge;

If θ is greater than 180 degree, then topological adjacency form in two sides is chimb;

If θ equals 180 degree, then topological adjacency form in two sides is tangent;

Described (3) secondary classification identification: on the basis of first-level class identification, the outer normal vector V of retention body ₁and V ₂as the benchmark identified further, obtain manifold midpoint recessed to vector, and external to vector V with two manifold respectively ₁and V ₂carry out angle calcu-lation, differentiate according to angle value, concrete grammar is:

If 1. topological adjacency form in two sides is tangent, writing-method is to vector V ₁for V _f1, V ₂for V _f2;

2. bending line mid point P is calculated _fthe normal plane F at place _f;

3. by normal plane F _frespectively with face F ₁, F ₂ask friendship, obtain and ask knot fruit intersection L ₁, L ₂;

4. intersection L is obtained ₁, L ₂mid point P ₁, P ₂;

5. mid point P is calculated ₁, P ₂the curvature C at place ₁, C ₂;

If 6. C ₁, C ₂be less than critical value Q, Q value 1.0e+5, obtain intersection L by CAA component application framework built-in interface ₁, L ₂mid point P ₁, P ₂the main method at place vows V _mn1, V _mn2;

7. compute vectors V is distinguished _f1with V _mn1angle theta ₁, and V _f2with V _mn2angle theta ₂;

$\begin{array}{cc}\cos \left({\mathrm{\&theta;}}_1\right)=\frac{|v_{f1}\&CenterDot;v_{\mathrm{mn}1}|}{\left|v_{f1}\right|\left|v_{\mathrm{mn}1}\right|}& \cos \left({\mathrm{\&theta;}}_2\right)=\frac{|v_{f2}\&CenterDot;v_{\mathrm{mn}2}|}{\left|v_{f2}\right|\left|v_{\mathrm{mn}2}\right|}\end{array}$

8. according to curvature and angle contrast, show that secondary classification recognition result is as follows:

If C ₁, C ₂all be greater than Q, then topological adjacency form in two sides is two truncation limits;

If C ₁be greater than Q, C ₂be less than Q, and θ ₂be less than 90 degree, then topological adjacency form in two sides is plano-concave trimming;

If C ₂be greater than Q, C ₁be less than Q, and θ ₁be less than 90 degree, then topological adjacency form in two sides is plano-concave trimming;

If C ₁be greater than Q, C ₂be less than Q, and θ ₂be greater than 90 degree, then topological adjacency form in two sides is plano-convex trimming;

If C ₂be greater than Q, C ₁be less than Q, and θ ₁be greater than 90 degree, then topological adjacency form in two sides is plano-convex trimming;

If C ₁, C ₂all be less than Q, and θ ₁be greater than 90 degree, θ ₂be less than 90 degree, then topological adjacency form in two sides is concavo-convex trimming;

If C ₁, C ₂all be less than Q, and θ ₁be less than 90 degree, θ ₂be greater than 90 degree, then topological adjacency form in two sides is concavo-convex trimming;

If C ₁, C ₂all be less than Q, and θ ₁, θ ₂all be less than 90 degree, then topological adjacency form in two sides is concave-concave trimming;

If C ₁, C ₂all be less than Q, and θ ₁, θ ₂all be greater than 90 degree, then topological adjacency form in two sides is biconvex trimming.

Described step 2) bending circular arc classification with identify, comprise (1) bending circular arc classification; (2) bending tool nose radius;

Described (1) bending circular arc classification: bending circular arc and the transition arc between web surface and crimp face are the bridges between web surface and crimp face, can be divided into inner concave shape and male type two kinds by bending direction;

Described (2) bending tool nose radius: by manifold F to be discriminated _dpwith web surface F _fbcarry out asking friendship, if success, obtain the bending line that two sides is common, get bending line mid point P _f; Calculate mid point P _fat face F _dp, F _fbin in vitro method to vector V _dpand V _fb; Calculate bending line and belong to F _dptime at mid point P _flocate anticlockwise cutting and vow V _tdp, calculate bending line and belong to F _fbtime at mid point P _flocate anticlockwise cutting and vow V _tfb; Calculate when bending line belongs to two respectively at mid point P _fthe normal vector V at place _ndp, V _nfb; Calculate two normal vector V _ndpto V _nfbwith V _tdpfor counterclockwise angle theta during reference, if θ equals 180 degree, then manifold to be discriminated is bending circular arc; Calculate bending line mid point P _fthe normal plane F at place _f; By F _fwith F _dpask friendship, obtain and ask knot fruit intersection L _dp; Calculate L _dpmid point P _dpthe main method at place vows V _mndp; Compute vectors V _dpwith V _mndpangle theta, if θ is less than 90 degree, then bending circular arc is inner concave shape; If θ is greater than 90 degree, then bending circular arc is male type.

Described step (3) crimp face identifies: by manifold F to be discriminated _dpwith male type bending circular arc F _zwcarry out asking friendship, if success, obtain the bending line that two sides is common, get bending line mid point P _f; Calculate mid point P _fat face F _dp, F _zwin in vitro method to vector V _dpand V _zw; Calculate bending line and belong to F _dptime at mid point P _flocate anticlockwise cutting and vow V _tdp, calculate bending line and belong to F _zwtime at mid point P _flocate anticlockwise cutting and vow V _tzw; Calculate when bending line belongs to two respectively at mid point P _fthe normal vector V at place _ndp, V _nzw; Calculate two normal vector V _ndpto V _nzwwith V _tdpfor counterclockwise angle theta during reference, if θ equals 180 degree, then manifold to be discriminated is crimp face.

Application example:

This example be premised on preceding solution under carry out.

Figure 3 shows that the idiographic flow of the Aircraft Sheet Metal Parts crimp characteristic recognition method that the present invention proposes, implementation step in order to: 1) load web surface (S1); 2) web surface adjacent side and proximal surface (S2) is extracted; 3) male type bending circular arc (S3) is identified; 4) bending circular arc adjacent side and proximal surface (S4) is extracted; 5) crimp face identifies (S5); Wherein:

Described step 1) load web surface (S1), in the model space, namely choose the manifold as web surface;

Step 2) extract web surface adjacent side and proximal surface (S2), namely ask with web surface in the model space and hand over successful manifold to be web adjacent surface, the sideline that adjacent surface and web surface are owned together is bending line;

Step 3) identify male type bending circular arc (S3), namely differentiate that the topological adjacency mode of web surface and its proximal surface is tangent, and proximal surface type is convex, concrete grammar is:

(1) identify whether two sides topological adjacency mode is tangent (as shown in Figure 4): first obtain manifold F to be discriminated ₁, with web surface F ₂common bending line, gets bending line mid point P _f(S6); Calculate mid point P _fat face F ₁, F ₂in in vitro method to vector V ₁and V ₂(S7); Calculate bending line and belong to face F ₁time at mid point P _flocate anticlockwise cutting and vow V _t1, calculate bending line and belong to face F ₂time at mid point P _flocate anticlockwise cutting and vow V _t2(S8); Calculate when bending line belongs to two manifold respectively at mid point P _ftime normal vector V _n1, V _n2(S9); Calculate two normal vector V _n1to V _n2with V _t1for the counterclockwise angle theta (S10) during reference, if θ equals 180 degree, then manifold to be discriminated is bending circular arc (S11), retains, and does further identification;

(2) identify whether proximal surface type is convex (as shown in Figure 5): writing-method is to vector V ₁for V _f1, V ₂for V _f2(S12); Calculate bending line mid point P _fthe normal plane F at place _f(S13); By normal plane F _frespectively with face F ₁, F ₂ask friendship, obtain and ask knot fruit intersection L ₁, L ₂(S14); Calculate L ₁, L ₂mid point P ₁, P ₂; Calculate mid point P ₁, P ₂the curvature C at place ₁, C ₂(S15); If C ₁, C ₂be greater than critical value Q, then F ₁, F ₂face is flat type (S16), otherwise calculates intersection L ₁, L ₂mid point P ₁, P ₂the main method at place vows V _mn1, V _mn2(S17); Compute vectors V respectively _f1with V _mn1, V _f2with V _mn2angle, if angle is greater than 90 degree, then this manifold is the bending circular arc (S19) of male type;

Step 4) obtain bending circular arc adjacent side and proximal surface (S4), namely ask with bending circular arc in the model space and hand over successful manifold, and be not web surface and bending circular arc proximal surface, the sideline that proximal surface and bending circular arc are owned together is bending line;

Step 5) crimp face identification (S5), namely differentiate whether bending circular arc and its proximal surface topological adjacency mode are tangent, and method is: first obtain manifold F to be discriminated ₁, with bending circular arc F ₂common bending line, gets bending line mid point P _f(S6); Calculate mid point P _fat face F ₁, F ₂in in vitro method to vector V ₁and V ₂(S7); Calculate bending line and belong to face F ₁time at mid point P _flocate anticlockwise cutting and vow V _t1, calculate bending line and belong to face F ₂time at mid point P _flocate anticlockwise cutting and vow V _t2(S8); Calculate when bending line belongs to two manifold respectively at mid point P _ftime normal vector V _n1, V _n2(S9); Calculate two normal vector V _n1to V _n2with V _t1for the counterclockwise angle theta (S10) during reference, if θ equals 180 degree, then manifold to be discriminated is crimp face (S11).

Claims (3)

1., based on a sheet metal crimp characteristic recognition method for topological adjacency, it is characterized in that, comprise the steps: 1) two sides topological adjacency identification; 2) classification of bending circular arc and identification; 3) crimp face identifies;

Described step 1) two sides topological adjacency identification, comprise the topological adjacency definition of (1) two sides; (2) first-level class identification; (3) secondary classification identification;

Described (1) two sides topological adjacency definition: suppose that two manifold produce after carrying out bending by an original face, by the form of two manifold at bending part, definition two sides topological adjacency: comprise first-level class, secondary classification;

Wherein, first-level class;

<1.1> concave edge: on bending line, the tangent plane of any point is all inside entity;

<1.2> chimb: on bending line, the tangent plane of any point is all outside entity;

<1.3> trimming: on bending line the tangent plane of any point and two manifold tangent;

Wherein trimming type, can carry out secondary classification again by the concavity and convexity at the two relative bending line places of manifold;

The two truncation limit of <2.1>: on bending line, the tangent plane of any point is tangent with two manifold, and coincidence;

The trimming of <2.2> plano-concave: on bending line the tangent plane of any point and two manifold tangent, and overlap with a manifold, tangent plane is inside the entity of non-coincidence manifold;

The trimming of <2.3> plano-convex: on bending line the tangent plane of any point and two manifold tangent, and overlap with a manifold, tangent plane is outside the entity of non-coincidence manifold;

The concavo-convex trimming of <2.4>: on bending line the tangent plane of any point and two manifold tangent, and not overlap with manifold, tangent plane inside the entity of a manifold, outside the entity of another manifold;

The trimming of <2.5> concave-concave: on bending line the tangent plane of any point and two manifold tangent, and do not overlap with manifold, tangent plane is inside the entity of two manifold;

The trimming of <2.6> concave-concave: on bending line the tangent plane of any point and two manifold tangent, and do not overlap with manifold, tangent plane is outside the entity of two manifold;

Described (2) first-level class identification: the form utilizing bending line, identify two sides topological adjacency, concrete grammar is:

1. two adjacent manifold F are obtained ₁, F ₂common sideline, i.e. bending line, get sideline mid point P _f;

2. mid point P is obtained by CAA component application framework built-in interface _fat F ₁, F ₂in in vitro method to vector V ₁and V ₂;

3. calculate bending line and belong to face F ₁time at mid point P _flocate anticlockwise cutting and vow V _t1, counterclockwise get P along bending line _f(t ₀) point of proximity P _{Δ f1}(t ₀+ Δ t), V _t1=P _{Δ f1}(t ₀+ Δ t)-P _f(t ₀), calculate bending line and belong to face F ₂time at mid point P _flocate anticlockwise cutting and vow V _t2, counterclockwise get P along bending line _f(t ₀) point of proximity P _{Δ f2}(t ₀+ Δ t), V _t2=P _{Δ f2}(t ₀+ Δ t)-P _f(t ₀);

4. calculate when bending line belongs to two manifold respectively at mid point P _ftime normal vector V _n1, V _n2;

V _n1＝V ₁×V _t1V _n2＝V ₂×V _t2

5. two normal vector V are calculated _n1to V _n2with V _t1for counterclockwise angle theta during reference, its process is:

A, acquisition V _n1to V _n2cross product V _s, i.e. V _n1with V _n2the plane Ax+By+Cz+D=0 formed, if V _swith V _t1angle is greater than 90 degree, by V _n1with V _n2exchange;

B, by V _n1coordinate along V _smove a certain distance, obtain outer 1 P of plane _n1(x ₀, y ₀, z ₀);

C, some P _n1projection line equation to plane is be converted into parametric equation and obtain x=x ₀-At, y=y ₀-Bt, z=z ₀-Ct, substitutes into plane equation and obtains t is substituted into projection line parametric equation and can obtain V _n1two-dimensional vector V planar _n1', in like manner obtain V _n2two-dimensional vector V planar _n2';

D, extraction V _n1' coordinate (a, b), obtain V _n1' vertical vector V _n1" (b ,-a);

E, calculating V _n1' and V _n2' angle theta ₁if, θ ₁equal 180 degree, so θ=θ ₁; 6 otherwise calculate V _n1" and V _n2' angle theta ₂if, θ ₂be less than 90 degree, so θ=θ ₁+ 180, otherwise θ=θ ₁;

If θ is less than 180 degree, then topological adjacency form in two sides is concave edge;

If θ is greater than 180 degree, then topological adjacency form in two sides is chimb;

If θ equals 180 degree, then topological adjacency form in two sides is tangent;

Described (3) secondary classification identification: on the basis of first-level class identification, the outer normal vector V of retention body ₁and V ₂as the benchmark identified further, obtain manifold midpoint recessed to vector, and external to vector V with two manifold respectively ₁and V ₂carry out angle calcu-lation, differentiate according to angle value, concrete grammar is:

If 1. topological adjacency form in two sides is tangent, writing-method is to vector V ₁for V _f1, V ₂for V _f2;

2. bending line mid point P is calculated _fthe normal plane F at place _f;

3. by normal plane F _frespectively with face F ₁, F ₂ask friendship, obtain and ask knot fruit intersection L ₁, L ₂;

4. intersection L is obtained ₁, L ₂mid point P ₁, P ₂;

5. mid point P is calculated ₁, P ₂the curvature C at place ₁, C ₂;

If 6. C ₁, C ₂be less than critical value Q, Q value 1.0e+5, obtain intersection L by CAA component application framework built-in interface ₁, L ₂mid point P ₁, P ₂the main method at place vows V _mn1, V _mn2;

7. compute vectors V is distinguished _f1with V _mn1angle theta ₁, and V _f2with V _mn2angle theta ₂;

$\cos \left({\mathrm{\&theta;}}_1\right)=\frac{|v_{f1}\&CenterDot;v_{\mathrm{mn}1}|}{\left|v_{f1}\right|\left|v_{\mathrm{mn}1}\right|}$ $\cos \left({\mathrm{\&theta;}}_2\right)=\frac{|v_{f2}\&CenterDot;v_{\mathrm{mn}2}|}{\left|v_{f2}\right|\left|v_{\mathrm{mn}2}\right|}$

8. according to curvature and angle contrast, show that secondary classification recognition result is as follows:

If C ₁, C ₂all be greater than Q, then topological adjacency form in two sides is two truncation limits;

If C ₁be greater than Q, C ₂be less than Q, and θ ₂be less than 90 degree, then topological adjacency form in two sides is plano-concave trimming;

If C ₂be greater than Q, C ₁be less than Q, and θ ₁be less than 90 degree, then topological adjacency form in two sides is plano-concave trimming;

If C ₁be greater than Q, C ₂be less than Q, and θ ₂be greater than 90 degree, then topological adjacency form in two sides is plano-convex trimming;

If C ₂be greater than Q, C ₁be less than Q, and θ ₁be greater than 90 degree, then topological adjacency form in two sides is plano-convex trimming;

If C ₁, C ₂all be less than Q, and θ ₁be greater than 90 degree, θ ₂be less than 90 degree, then topological adjacency form in two sides is concavo-convex trimming;

If C ₁, C ₂all be less than Q, and θ ₁be less than 90 degree, θ ₂be greater than 90 degree, then topological adjacency form in two sides is concavo-convex trimming;

If C ₁, C ₂all be less than Q, and θ ₁, θ ₂all be less than 90 degree, then topological adjacency form in two sides is concave-concave trimming;

If C ₁, C ₂all be less than Q, and θ ₁, θ ₂all be greater than 90 degree, 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, is characterized in that, described step 2) bending circular arc classification with identify, comprise (1) bending circular arc classification; (2) bending tool nose radius;

Described (1) bending circular arc classification: bending circular arc and the transition arc between web surface and crimp face are the bridges between web surface and crimp face, can be divided into inner concave shape and male type two kinds by bending direction;

Described (2) bending tool nose radius: by manifold F to be discriminated _dpwith web surface F _fbcarry out asking friendship, if success, obtain the bending line that two sides is common, get bending line mid point P _f; Calculate mid point P _fat face F _dp, F _fbin in vitro method to vector V _dpand V _fb; Calculate bending line and belong to F _dptime at mid point P _flocate anticlockwise cutting and vow V _tdp, calculate bending line and belong to F _fbtime at mid point P _flocate anticlockwise cutting and vow V _tfb; Calculate when bending line belongs to two respectively at mid point P _fthe normal vector V at place _ndp, V _nfb; Calculate two normal vector V _ndpto V _nfbwith V _tdpfor counterclockwise angle theta during reference, if θ equals 180 degree, then manifold to be discriminated is bending circular arc; Calculate bending line mid point P _fthe normal plane F at place _f; By F _fwith F _dpask friendship, obtain and ask knot fruit intersection L _dp; Calculate L _dpmid point P _dpthe main method at place vows V _mndp; Compute vectors V _dpwith V _mndpangle theta, if θ is less than 90 degree, then bending circular arc is inner concave shape; If θ is greater than 90 degree, then bending circular arc is male type.

3. a kind of sheet metal crimp characteristic recognition method based on topological adjacency according to claim 1, is characterized in that, described step (3) crimp face identifies: by manifold F to be discriminated _dpwith male type bending circular arc F _zwcarry out asking friendship, if success, obtain the bending line that two sides is common, get bending line mid point P _f; Calculate mid point P _fat face F _dp, F _zwin in vitro method to vector V _dpand V _zw; Calculate bending line and belong to F _dptime at mid point P _flocate anticlockwise cutting and vow V _tdp, calculate bending line and belong to F _zwtime at mid point P _flocate anticlockwise cutting and vow V _tzw; Calculate when bending line belongs to two respectively at mid point P _fthe normal vector V at place _ndp, V _nzw; Calculate two normal vector V _ndpto V _nzwwith V _tdpfor counterclockwise angle theta during reference, if θ equals 180 degree, then manifold to be discriminated is crimp face.