CN102436217A - Method for reconstructing web processing drive geometry of slot characteristic of aircraft structure - Google Patents

Abstract

The invention discloses a method for automatically reconstructing a web processing drive geometry of a slot characteristic of an aircraft structure. The method comprises the following steps of: by using all side faces, recess surfaces and corner surfaces of the slot characteristic, calculating a boundary; by using a web surface and a base angle surface of an outer ring of the web surface, calculating a boundary; combining the two boundaries into a whole; eliminating edges which do not meet requirements; in the sketch environment, projecting the screened edges to the web surface to obtain intersection points of the edges after projection; cutting off the intersected edges by using the intersection points; based on all points and edges which are projected and cut off, constructing an attribute edge point diagram which comprises the edges, the points and edge and point information; calculating all minimum surrounding contours in the attribute edge point diagram; and acquiring an effective minimum surrounding contour from all minimum surrounding contours as the web processing drive geometry. By adoption of the method, the problem of difficulty in automatic extraction of the web processing drive geometry is effectively solved, and the quality and efficiency in automatic programming of a web during numerical control process programming are improved.

Description

The processing of aircraft structure cavity feature web drives the geometry reconstruction method

Technical field

The present invention relates to a kind of web processing and drive the geometry reconstruction method; Relate in particular to a kind of aircraft structure cavity feature web processing and drive the geometry reconstruction method, belong to CAD (computer-aided design (CAD))/CAPP (design of CAP process)/CAM (computer-aided manufacturing) technical field.

Background technology

The aircraft structure complex structure, machining feature is many, comprises a large amount of free form surfaces, intersects characteristic and special machining area, and difficulty of processing is big.Domestic each large aerospace enterprise drops into tens billion of a huge sum of money and buys a large amount of advanced numerically-controlled machines, but the equipment effective rate of utilization is low, and its main cause is that numerical control programming efficient is low, quality is unstable.Need in the aircraft structure numerical control programming process manual work pick a large amount of how much, quantity of parameters is set and creates a large amount of assisted geometrics.Along with increasing of single piece, thin-wall part and special material spare, the numerical control programming workload increases considerably, and the numerical control programming of aircraft structure becomes one of important bottleneck that influences the aircraft development cycle day by day.

The automatic acquisition process of activation bit is called machining feature reconstruct.Driving how much automatic reconfigurations is emphasis and difficult point in the machining feature reconstruct.Drive how much and lie in the geological information of machining feature, need the treated data mode that cutter rail generating algorithm can directly be used that converts into.

In the cad model of B-rep (B reps) expression, face is organized its topological structure with point, limit, ring.. the border of face is made up of ring, ring and outer shroud in ring is divided into, and outer shroud has and only has 1, and interior ring can have a plurality of.Outer shroud constitutes the outline of face, and interior ring constitutes hole profile or island profile.Inner and outer rings is how much of the direct drivings of web processing cutter rail generating algorithm.

The aircraft structure vallecular cavity is complex-shaped, closure differs, and the vallecular cavity sidewall comprises a large amount of free form surfaces, open and close the angle and deposit, web face self outer shroud can not be directly as the biasing foundation of equal space line.Therefore, must revise outer shroud, comprise a large amount of curve cutting splicing and calculate, to guarantee that cutter neither interferes with the side in working angles, it is residual also can not produce cutting.Present method all is under three-dimensional environment, to carry out web to drive how much choosing and cutting, and workload is big, and correctness is difficult to guarantee, especially in calculation process automatically, is difficult to generate effective closure and drives how much.

Summary of the invention

Technical matters to be solved by this invention is to overcome the deficiency of structural member cavity feature web processing driving geometrical calculation method in the existing CAD/CAM system, provides a kind of aircraft structure cavity feature web processing to drive the method for how much automatic reconfigurations.

Aircraft structure cavity feature web processing of the present invention drives how much automatic reconfiguration methods and may further comprise the steps:

Step 1, all sides that combine a cavity feature, sink face and corner face are labeled as JOIN.1;

Step 2, according to the syntople between all faces among the JOIN.1, calculate its border, be labeled as: BOUNDARY.1;

Step 3, combination web face and web outer shroud base angle face are labeled as: JOIN.2;

Step 4, according to the syntople between all faces among the JOIN.2, obtain its border, be labeled as: BOUNDARY.2;

All limits among step 5, combination BOUNDARY.1 and the BOUNDARY.2 are an integral body, are labeled as: JOIN.3;

Unwanted limit is rejected on limit among step 6, the screening JOIN.3;

Step 7, under the sketch environment, with the screening after JOIN.3 in the limit to the projection of web face, try to achieve the intersection point on projection back and limit, and utilize intersection point to interrupt crossing limit, the result queue after the processing is SKETCH.1;

Step 8, based on projection and after interrupting have a few and the limit, structure contains the attribute edge point figure of limit, point and limit and dot information;

Step 9, calculate among the attribute edge point figure all minimum profiles that surround;

Step 10, obtain the effectively minimum profile that surrounds, be final web profile processing and drive how much from all minimum profiles that surround.

The concrete steps of said step 2 are: 1. take out the face among the JOIN.1 in order one by one; 2. extract the outer shroud border of this face; 3. take out the limit in the outer shroud border in order one by one; 4. judge whether this limit belongs to the outer annular edge of other face among the JOIN.1, if then return step 3., otherwise this sideline belongs to the border of JOIN.1, lists it in BOUNDARY.1.

The method on the limit of described screening JOIN.3 is: 1. reject limit identical among the JOIN.3; 2. reject straight flange perpendicular to the web face.

The concrete steps of said step 7 are: the three-dimensional limit that 1. will obtain obtains drop shadow curves such as plane and straight line, plane conic section or plane SPL to the web plane projection; 2. for the curve that overlaps fully, only keep one,, obtain intersection and only keep one for the curve that partially overlaps; 3. obtain intersection points all between the curve then, corresponding curve is broken into two curves, finally obtain netted curve row at each intersection point place.

The implementation method of above process in CAD/CAM software: create sketch based on web plane, JOIN.3 integral body to the sketch projection, can be realized sideline among the JOIN.3 to the projection of web face, find intersection such as interrupts at operation;

The concrete steps of said step 8 are: 1. defining point class MyVertex, member variable comprise that mathematical notation a little, the topological representation of point and the topological limit that links to each other with point are listed as; 2. define limit class MyEdge, member variable comprises topological representation, the character representation on limit, the switching mouth attribute-bit on limit, starting point, the terminating point on limit; The tabulation of a 3. newly-built MyVertex class is labeled as: MYVERTEX_LIST, and the tabulation of a newly-built MyEdge class is labeled as: MYEDGE_LIST; 4. take out the limit among the SKETCH.1 in order one by one; The object of a 5. newly-built MyEdge class will be worked as attribute in front and insert in the corresponding member variable, and this object will be listed among the MYEDGE_LIST; 6. take out when starting point in front, be labeled as STARTPOINT.Judge whether STARTPOINT is the member among the MYVERTEX_LIST, if, then skipped to for the 7. step, otherwise the object of a newly-built MyVertex class, the attribute of STARTPOINT is inserted among the corresponding member and with this object listed among the MYVERTEX_LIST; 7. take out when terminating point in front, be labeled as ENDPOINT.Judge whether ENDPOINT is the member among the MYVERTEX_LIST, if not the object of a then newly-built MyVertex class, the attribute of ENDPOINT is inserted in the corresponding member variable, and this object is listed among the MYVERTEX_LIST.

The concrete steps of said step 9 are:

1. in attribute edge point figure, appoint and get one section curve l _i, get l _iA summit M _i(x ₀, y ₀, z ₀) be current node, the combination of mark current curves and current node is designated as (l _i, M _i);

2. will make up (l _i, M _i) some M _iAs the starting point of segment of curve, assumed curve l _iAt a M _iCutting arrow does

With current node M _iOther line segments that connect cut arrow

3. remember that the outer normal direction of web does

Definition

Sense of rotation do

So Around a M _i, with

Be the initial direction rotation,

In the vector, the corresponding article one of the vector that overlaps with it limit is current minimum next bar limit that surrounds outline line, is designated as l _I1, get l _I1The another one summit, be designated as M _I1, judge l this moment _I1Whether with l _iIdentical, if difference then judge (l _I1, M _I1) mark whether, if there is not mark, then with (l _I1, M _I1) assignment gives (l _i, M _i) change step over to 2..

4. get l _iAnother summit be current node M _i' (x ₀', y ₀', z ₀'), judge (l _i, M _i') mark whether, if there is not mark, then with (l _i, M _i') assignment gives (l _i, M _i) change step over to 2..

5. obtain minimums all in the sketch and surround profile.

Judge in said

vector, be with the concrete steps of

first vector that coincides:

1., with M _iBe the center of circle, radius is 1 to do circle.This circle with

Intersect at a little

With Vector intersects at a little $L_n=M_i+{\stackrel{\→}{r}}_n.$

2. with L ₀Be n vector of starting point structure $\stackrel{}{V_{}}$ $\stackrel{\&RightArrow;}{{}_1}=L_1-L_0=\stackrel{\&RightArrow;}{{\mathrm{<figure-callout\; id="1"\; label="r"\; filenames="HDA0000100030910000021.png,HDA0000100030910000054.png"\; state="\{\{state\}\}">r</figure-callout>}}_1}-\stackrel{\&RightArrow;}{r_0},$ $\stackrel{\&RightArrow;}{{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="HDA0000100030910000055.png,HDA0000100030910000061.png"\; state="\{\{state\}\}">V</figure-callout>}}_2}=L_2-L_0=\stackrel{\&RightArrow;}{{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HDA0000100030910000055.png,HDA0000100030910000061.png"\; state="\{\{state\}\}">r</figure-callout>}}_2}-\stackrel{\&RightArrow;}{r_0},...,$ $\stackrel{\&RightArrow;}{V_n}=L_n-L_0=\stackrel{\&RightArrow;}{r_n}-\stackrel{\&RightArrow;}{r_0}.$

3. calculate the angle between

and

vector then respectively, the vector that minimum angle is corresponding is and first vector that coincides.

The concrete steps of said step 10 are:

1. the minimum profile that surrounds of all that obtain can be expressed as: LOOP0, and LOOP1 ..., LOOPn;

2. get rid of the maximum minimum of area surround profile LOOPi (0≤i≤n), the remaining minimum profile that surrounds can be expressed as: LOOP0, LOOP1 ... LOOPi-1, LOOPi+1 ..., LOOPn;

3. travel through the remaining minimum profile that surrounds, calculate the current minimum profile central point that surrounds, cross the straight line that central point is done the vertical web face, if this straight line does not intersect with JOIN.1, the then current minimum profile that surrounds is effective minimum profile that surrounds.

The inventive method efficient is high; It is high that the web processing that generates drives how much quality; The assisted geometric that generates in the computation process is few, has saved storage space, solved effectively the processing of aircraft structure cavity feature web drive geometrical calculation loaded down with trivial details, be difficult to generate automatically how much the problem that effectively drives.

Description of drawings

Fig. 1. aircraft structure cavity feature web processing of the present invention drives how much and generates method flow diagram;

Fig. 2. the algorithm flow chart on faying face border;

Fig. 3. netted curve row.Wherein, digital 1-11 representes the numbering of curve row; LOOP1-LOOP6 representes the minimum profile that surrounds;

Fig. 4. the definition of attribute edge point figure class;

Fig. 5. the structure process flow diagram of attribute edge point figure;

Fig. 6. node is cut arrow on line segment.M wherein _iBe current curves l _iCurrent node,

Be l _iAt M _iThe unit tangent vector at place;

Fig. 7. vector overlaps judges synoptic diagram.Wherein

Be current curves l ₀At current node M _iThe unit tangent vector at place,

For with M _iThe curve l that links to each other _nAt M _iThe unit tangent vector at place,

For

Sense of rotation;

Fig. 8. the groove that uses among the embodiment;

Fig. 9 .Join.1, the combination of all sides of expression cavity feature, sink face and corner face;

Figure 10 .Join.2, the web face of expression cavity feature and the combination of base angle face;

The sketch of Figure 11 .Join.3 after the projection of web face, digital 1-5 representes to have in the sketch position of intersection;

Figure 12. the enlarged drawing that " 1 " is located among Figure 11;

Figure 13. method of the present invention realizes figure as a result, and Guidel is the effectively minimum profile that surrounds, and Bottom is the web face;

Embodiment

Below in conjunction with embodiment and accompanying drawing the present invention is further specified.Adopt C Plus Plus to realize that the processing of aircraft structure cavity feature web drives automatic reconfiguration method how much, the CAD/CAM software platform of employing is CATIA, and development platform is CATIA secondary developing platform CAA, and the concrete steps of enforcement are:

Step 1, execution " Join " order engage all sides of a cavity feature, sink face and corner face, and be as shown in Figure 9, obtains " Join.1 " characteristic;

Step 2, execution " Boundary " are ordered, and calculate the border of " Join.1 ", obtain " Boundary.1 " characteristic;

Step 3, execution " Join " order engage web face and web outer shroud base angle face, and be shown in figure 10, obtains " Join.2 " characteristic;

Step 4, execution " Boundary " are ordered, and calculate the border of " Join.2 ", obtain " Boundary.2 " characteristic;

Step 5, execution " Join " order are combined as a whole " Boundary.1 " and " Boundary.2 ", obtain " Join.3 " characteristic;

Step 6, under the sketch environment, " Join.3 " is to the projection of web face, shown in figure 11, obtain " sketch of Join.3 after the projection of web face " characteristic, in CATIA, system interrupts all intersection curves automatically behind the projection sketch;

Step 7, structure contain the attribute edge point figure of limit, point and limit and dot information.Concrete steps are: 1. defining point class MyVertex, member variable comprise that mathematical notation a little, the topological representation of point and the topological limit that links to each other with point are listed as; 2. define limit class MyEdge, member variable comprises topological representation, the character representation on limit, the switching mouth attribute-bit on limit, starting point, the terminating point on limit; The tabulation of a 3. newly-built MyVertex class is labeled as: MYVERTEX_LIST, and the tabulation of a newly-built MyEdge class is labeled as: MYEDGE_LIST; 4. take out the limit among the SKETCH.1 in order one by one; The object of a 5. newly-built MyEdge class will be worked as attribute in front and insert in the corresponding member variable, and this object will be listed among the MYEDGE_LIST; 6. take out when starting point in front, be labeled as STARTPOINT.Judge whether STARTPOINT is the member among the MYVERTEX_LIST, if, then skipped to for the 7. step, otherwise the object of a newly-built MyVertex class, the attribute of STARTPOINT is inserted among the corresponding member and with this object listed among the MYVERTEX_LIST; 7. take out when terminating point in front, be labeled as ENDPOINT.Judge whether ENDPOINT is the member among the MYVERTEX_LIST, if not the object of a then newly-built MyVertex class, the attribute of ENDPOINT is inserted in the corresponding member variable, and this object is listed among the MYVERTEX_LIST.

Step 8, calculate among the attribute edge point figure all minimum profiles that surround.The enlarged drawing that " 1 " is located among Figure 11 is shown in figure 12, and " 2 " to " 5 " are located to locate similar with " 1 ";

Node among Figure 12 comprises ABCDEFGHIJ, and wherein minimum encirclement profile is ABCD and DGA etc., and the step that obtains minimum encirclement profile ABCD is following.

Curve among the traversal attribute edge point figure supposes that current curves is AD, and a summit A who gets AD is a current node, the combination of mark current curves and current node, be designated as (AD, D);

At combination (AD; D) in; D is a starting point; Make the arrow of cutting of segment of curve DA, DG, DE and DC, and unitization, be designated as

respectively

Note web face the sense of rotation that outer normal direction be

defines

so is

around a D; With

is the initial direction rotation; In

vector; The corresponding article one of the vector that overlaps with it limit is DC; Be current minimum next bar limit that surrounds outline line; Judge whether DC is identical with current curves AD this moment; If difference then judge (DC; C) mark whether; If there is not mark; Then with (2. DC C) changes step over to;

Step 2. with step cyclic process 3. can obtain successively combination (CB, B), (BA is A) with (AD, D), (AD, the curve in D) is identical with current curves AD, can judge that the current minimum encirclement profile that obtains is AD, DC, CB and BA, i.e. ABCD at this moment.

Step 9, circulation are adopted the method in the step 8 just can obtain all minimums and are surrounded profile, delete the wherein maximum profile of area.Travel through each minimum profile that surrounds and obtain its central point; Then through this central point; Do the straight line vertical with the web face, if non-intersect with " Join.1 " characteristic, should minimum encirclement profile be the feature reconstruction result so; The promptly effectively minimum profile that surrounds, the web processing cutter rail that the web that obtains shown in figure 13 drives how much and generated.

Claims (8)

1. an aircraft structure cavity feature web is processed the method that drives how much automatic reconfigurations, it is characterized in that may further comprise the steps:

Step 1, all sides that combine a cavity feature, sink face and corner face are labeled as JOIN.1;

Step 2, according to the syntople between all faces among the JOIN.1, extract its border, be labeled as: BOUNDARY.1;

Step 3, combination web face and web outer shroud base angle face are labeled as: JOIN2;

Step 4, according to the syntople between all faces among the JOIN.2, extract its border, be labeled as: BOUNDARY.2;

All limits among step 5, combination BOUNDARY.1 and the BOUNDARY.2 are an integral body, are labeled as: JOIN.3;

Unwanted limit is rejected on limit among step 6, the screening JOIN.3;

Step 7, under the sketch environment, with the screening after JOIN.3 in the limit to the projection of web face, try to achieve the intersection point on projection back and limit, and utilize intersection point to interrupt crossing limit, the result queue after the processing is SKETCH.1;

Step 8, based on projection and after interrupting have a few and the limit, structure contains the attribute edge point figure of limit, point and limit and dot information;

Step 9, calculate among the attribute edge point figure all minimum profiles that surround, minimum to surround outline definition be one group of end to end plane curve that mutually disjoints;

Step 10, obtain the effectively minimum profile that surrounds, be final web profile processing and drive how much from all minimum profiles that surround.

2. a kind of aircraft structure cavity feature web processing as claimed in claim 1 drives the method for how much automatic reconfigurations, it is characterized in that the concrete steps of said step 2 are: 1. take out the face among the JOIN.1 in order one by one; 2. extract the outer shroud border of this face; 3. take out the limit in the outer shroud border in order one by one; 4. judge whether this limit belongs to the outer annular edge of other face among the JOIN.1, if then return step 3., otherwise this sideline belongs to the border of JOIN.1, lists it in BOUNDARY.1.

3. a kind of aircraft structure cavity feature web processing as claimed in claim 1 drives the method for how much automatic reconfigurations, it is characterized in that, the method on the limit of described screening JOIN.3 is: 1. reject limit identical among the JOIN.3; 2. reject straight flange perpendicular to the web face.

4. a kind of aircraft structure cavity feature web processing as claimed in claim 1 drives the method for how much automatic reconfigurations, and it is characterized in that the concrete steps of said step 7 are: the three-dimensional limit that 1. will obtain obtains drop shadow curve to the web plane projection; 2. for the curve that overlaps fully, only keep one,, obtain intersection and only keep one for the curve that partially overlaps; 3. obtain intersection points all between the curve, corresponding curve is broken into two curves, finally obtain netted curve row at each intersection point place.

5. a kind of aircraft structure cavity feature web processing as claimed in claim 1 drives the method for how much automatic reconfigurations; It is characterized in that; The concrete steps of said step 8 are: 1. defining point class MyVertex, member variable comprise that mathematical notation a little, the topological representation of point and the topological limit that links to each other with point are listed as; 2. define limit class MyEdge, member variable comprises topological representation, the character representation on limit, the switching mouth attribute-bit on limit, starting point, the terminating point on limit; The tabulation of a 3. newly-built MyVertex class is labeled as: MYVERTEX_LIST, and the tabulation of a newly-built MyEdge class is labeled as: MYEDGE_LIST; 4. take out the limit among the SKETCH.1 in order one by one; The object of a 5. newly-built MyEdge class will be worked as attribute in front and insert in the corresponding member variable, and this object will be listed among the MYEDGE_LIST; 6. take out when starting point in front, be labeled as STARTPOINT; Judge whether STARTPOINT is the member among the MYVERTEX_LIST, if, then skipped to for the 7. step, otherwise the object of a newly-built MyVertex class, the attribute of STARTPOINT is inserted among the corresponding member and with this object listed among the MYVERTEX_LIST; 7. take out when terminating point in front, be labeled as ENDPOINT; Judge whether ENDPOINT is the member among the MYVERTEX_LIST, if not the object of a then newly-built MyVertex class, the attribute of ENDPOINT is inserted in the corresponding member variable, and this object is listed among the MYVERTEX_LIST.

6. a kind of aircraft structure cavity feature web processing as claimed in claim 1 drives the method for how much automatic reconfigurations, it is characterized in that the concrete steps of said step 9 are:

1. in attribute edge point figure, appoint and get one section curve l _i, get l _iA summit M _i(x ₀, y ₀, z ₀) be current node, the combination of mark current curves and current node is designated as (l _i, M _i);

2. will make up (l _i, M _i) some M _iAs the starting point of segment of curve, assumed curve l _iAt a M _iCut and vow and to do

With current node M _iOther line segments that connect cut arrow

3. remember that the outer normal direction of web does Definition Sense of rotation do So

Around a M _i, with Be the initial direction rotation, In the vector, the corresponding article one of the vector that overlaps with it limit is current minimum next bar limit that surrounds outline line, is designated as l _I1, get l _I1The another one summit, be designated as M _I1, judge l this moment _I1Whether with l _iIdentical, if difference then judge (l _I1, M _I1) mark whether, if there is not mark, then with (l _I1, M _I1) assignment gives (l _i, M _i) change step over to 2.;

4. get l _iAnother summit be current node M _i' (x ₀', y ₀', z ₀'), judge (l _i, M _i') mark whether, if there is not mark, then with (l _i, M _i') assignment gives (l _i, M _i) change step over to 2.;

5. obtain minimums all in the sketch and surround profile;

7. a kind of aircraft structure cavity feature web processing as claimed in claim 6 drives the method for how much automatic reconfigurations; It is characterized in that; Judge in said

vector, be with the concrete steps of

first vector that coincides:

1. with M _iBe the center of circle, radius is 1 to do circle, this circle with

Intersect at a little

With

Vector intersects at a little $L_n=M_i+\stackrel{\&RightArrow;}{r_n};$

2. with L ₀Be n vector of starting point structure ${\stackrel{\&RightArrow;}{V}}_1=L_1{-L}_0=\stackrel{\&RightArrow;}{r_1}\stackrel{\&RightArrow;}{-r_0},$ ${\stackrel{\&RightArrow;}{V}}_2=L_1{-L}_0=\stackrel{\&RightArrow;}{r_2}\stackrel{\&RightArrow;}{-r_0},...,$ ${\stackrel{\&RightArrow;}{V}}_n=L_n{-L}_0=\stackrel{\&RightArrow;}{r_n}\stackrel{\&RightArrow;}{-r_0};$

3. calculate the angle between

and

vector then respectively, the vector that minimum angle is corresponding is and first vector that coincides;

8. a kind of aircraft structure cavity feature web processing as claimed in claim 1 drives the method for how much automatic reconfigurations, it is characterized in that the concrete steps of said step 10 are:

1. the minimum profile that surrounds of all that obtain can be expressed as: LOOP0, and LOOP1 ..., LOOPn;

2. get rid of the maximum minimum of area surround profile LOOPi (0≤i≤n), the remaining minimum profile that surrounds can be expressed as: LOOP0, LOOP1 ... LOOPi-1, LOOPi+1 ..., LOOPn;

3. travel through the remaining minimum profile that surrounds, calculate the current minimum profile central point that surrounds, cross the straight line that central point is done the vertical web face, if this straight line does not intersect with JOIN.1, the then current minimum profile that surrounds is effective minimum profile that surrounds.

Images