CN104375464A - Aircraft skin milling efficient machining path automatic generating method - Google Patents

Abstract

The invention discloses an aircraft skin milling efficient machining path automatic generating method and belongs to the technical field of CAD/CAM. The method is characterized by comprising the steps that skin part subsidence machining features are obtained at first; an preferable machining strategy is determined according to geometrical features of the subsidence machining features; an equidistant line is generated based on the subsidence preferable machining strategy and the typical machining technology; a machining path is generated based on the equidistant line connection rule; an equal-step-pitch, cross-free, cutter-lifting-free and residue-free efficient subsidence feature machining path is generated finally through residue detection processing. The efficient tool path generating method is provided for skin part numerical control milling, and the aircraft skin milling efficient machining path automatic generating method is particularly applied for tool path generation in the skin mirror image milling machining method, and is high in calculation efficiency, accuracy and applicability, and capable of relieving programming workloads of engineers greatly.

Description

A kind of aircraft skin milling highly-efficient processing track automatic generation method

Technical field

The present invention relates to a kind of CAD/CAM technology technology of machining, particularly relate to a kind of aircraft skin sink the step pitches such as mirror image milling, without intersecting machining locus rapid generation, specifically a kind of aircraft skin milling highly-efficient processing track automatic generation method.

Background technology

Along with the fast development of China's Aviation Industry, C919 etc. are large, and Aircraft Project obtains increasing attention, has also promoted the skill upgrading of aviation, especially in digital control processing field simultaneously.Aircraft skin class part is the important feature parts in large aircraft, compare the aircraft skin of rivet interlacement in the past, the features such as current structure-integrated covering enormous size, complex structure, have thin-walled, single-curvature or hyperbolicity profile, the inner groove structure containing complex contour.

Current domestic covering mirror image milling technology of having introduced is in order to process newly designed aircraft skin part.But the requirement of tool setting rail in reality processing of this technology is very high, the step pitch such as should to meet, cutter rail zero lap, meets noresidue again, and pilot process is without cutter lifting.Current each large commercialization CAM software all cannot provide and meet the above suitable cutter rail required, so can only lean on artificial hand animation cutter rail, efficiency is extremely low, is strongly depend on the experience of people, and Programming's quality is unstable, the part process-cycle of seriously delaying.

For this situation, this patent proposes a kind of aircraft skin milling highly-efficient processing track automatic generation method, belongs to CAD/CAM technical field.First the method obtains skin part and to sink machining feature, preferred Processing Strategies is determined according to the geometrical property of undercut nature, equal space line is generated based on sagging preferred Processing Strategies and exemplary process, machining locus is generated based on equal space line concatenate rule, finally by residual detecting process, the step pitches such as generation, without intersecting, without cutter lifting, the efficient vallecular cavity mirror image Milling Process track that sink of noresidue, for covering mirror image method for milling provides effective knife rail generating method, counting yield is high simultaneously, accuracy is high, applicability is strong, greatly can alleviate the programing work amount of engineering staff.

Summary of the invention

Cannot provide for aircraft skin mirror image milling pattern the machining locus met the demands for current commercialization CAM software, and current manual's manual programming draws machining locus, machining prgraming efficiency is low, programming stability, of poor quality, the problems such as dirigibility is not enough.Invent a kind of aircraft skin milling highly-efficient processing track automatic generation method.

Technical scheme of the present invention is as follows:

A kind of aircraft skin milling highly-efficient processing track automatic generation method, is characterized in that it comprises the following steps:

First, obtain the geometric element of undercut nature to be processed, determine cutter orbit making strategy in conjunction with operation resource storehouse;

Secondly, according to undercut nature geometric element and cutter orbit making strategy, adopt the mode of biased outline line to generate equal space line, will treat that biased line segment is divided three classes by its characteristic, according to equal space line create-rule, automatically generate all kinds of equal space line;

3rd, according to equal space line concatenate rule, by the head and the tail connection in an orderly manner of three class equal space lines, form a curve, as the cutter rail of covering milling highly-efficient processing;

4th, by carrying out residue detection and the optimization process of cutter rail to existing cutter rail, ensureing the cutter rail noresidue generated, and being applicable to all kinds of undercut nature of covering.

The described rail of stationary knife really generation strategy refers to, by analyzing sagging silhouette edge convex-concave feature and based on sagging bottom surface curvature characteristic, determining process tool, preferably machine direction and cutting width in conjunction with operation resource storehouse:

1) process tool is determined, by analyzing the concavity of undercut nature silhouette edge, calculate the minimum profile curvature radius of concave edge, as the least radius limits value of cutter, analyze the radius-of-curvature in face, undercut nature base angle simultaneously, as cutter base angle radius reference value, in operation resource storehouse, choose the cutter that one or more are suitable;

2) preferably machine direction is determined, because covering milling of sinking adopts and cuts along the cutter shaft of bottom surface normal direction, consider for Machine kinematics, significantly pivot angle change should be reduced for five-axis linkage machine tools work in-process as far as possible, therefore the direction should preferably getting covering Curvature varying minimum processes, namely increase the cutter rail length in this direction, by analyzing the Curvature varying of sagging silhouette edge, be preferred machine direction with the limit that radius-of-curvature is maximum as far as possible;

3) after cutter and preferred orientations are determined, can determine that the scope of cutting width CW is as follows:

The lower limit of CW is wherein d is the safe handling distance that ultrasonic thickness test device is reserved, and in this example, d is set to 3mm.

The upper limit of CW is wherein TD is tool diameter, and TCR is cutter base angle radius.

Described generates equal space line according to equal space line create-rule and undercut nature geometric element, and the generation foundation using equal space line as final cutter rail, wherein equal space line is divided into three types, and first is the I class equal space line parallel with preferred machine direction.Second be with machine direction nonparallel class circular arc line as II class equal space line, the 3rd be with machine direction nonparallel class straight line as III class equal space line.

Described automatically generate equal space line based on three class equal space line create-rules and refer to:

First extract and the approximately parallel profile sideline of preferred machine direction, deposit in L _pal, less parallel is here because covering may for hyperbolicity part, and two corresponding sidelines can not be completely parallel, carries out following steps after extraction:

1) for L _palnumber when being 2, sink for typical case is common, first its equal space line generation method is biased all profile borders with the effective radius of clean-up of cutter, as the final cutter rail L along profile ring cutting _{cont_Offset1}; Secondly by L _{cont_Offset1}in with L _palcorresponding limit as I class equal space line, and according to maximum distance between both sides and cut wide region, to L _palmiddle sideline is biased, and obtains all I class equal space lines; 3rd by L _{cont_Offset1}middle remaining sides is all inwardly biased cuts wide lower limit, and using wherein circular arc class as II class equal space line, the conduct III class equal space line of class straight line; I class equal space line and II class equal space line and III class equal space line to carry out crossingly interrupting process by the 4th, obtain final all kinds of equal space line;

2) for L _palnumber when being greater than 2, for complexity is sunk, its equal space line generation method is first same is biased all profile borders with the effective radius of clean-up of cutter, as the final cutter rail L along profile ring cutting _{cont_Offset1}; Secondly by L _{cont_Offset1}in with L _palcorresponding limit is extracted, and the region between every two adjacent edges is divided into convex, recessed two kinds of situations, for recessed region by its I class line equidistant odd number bar line, corresponding convex domain by its I class equal space line equidistant even numbers bar line, and using all equal space lines as I class equal space line; 3rd by L _{cont_Offset1}middle remaining sides is all inwardly biased cuts wide lower limit, and using wherein circular arc class as II class equal space line, the conduct III class equal space line of class straight line; In 4th each region, I class equal space line and II class equal space line and III class equal space line are carried out crossingly interrupting process, obtain final all kinds of equal space line.

Described according to equal space line concatenate rule, by three class equal space lines in an orderly manner head and the tail connect, the cutter rail forming covering milling highly-efficient processing refers to:

1) first by the every bar line in three class equal space lines, increase the attribute n of two end points, n represents the number of current endpoint place equal space line;

2) sink for each, traversal from an I class equal space line at most edge, judge the n attribute of current traversal end points, if n=2, directly traverse connected line, if n>2, carry out selection traversal according to concatenate rule, and delete redundancy limit, finally obtain by the end to end complete curve of all kinds of line, as initial manufacture track;

Described carry out selection traversal according to concatenate rule and refer to:

If current traversal point n=3, then continue traversal according to the following rules:

1) current traversal line is the equidistant line style of I class (hereinafter referred to as I type), when descending connecting line is II class equal space line (hereinafter referred to as II type), III class equal space line (hereinafter referred to as type III), traversal type III line, deletes the connecting line of corresponding II molded line and n=2 thereof simultaneously;

2) current traversal line is II type, and when descending connecting line is I, type III, traversal I molded line, deletes the connecting line of corresponding type III line and n=2 thereof simultaneously;

3) current traversal line is II type, and when descending connecting line is I, II type, traversal I molded line, deletes the connecting line of corresponding II molded line and n=2 thereof simultaneously;

4) current traversal line is type III, and when descending connecting line is I, II type, traversal I molded line, deletes the connecting line of corresponding II molded line and n=2 thereof simultaneously;

5) current traversal line is type III, and when descending connecting line is I, type III, traversal I molded line, deletes the connecting line of corresponding type III line and n=2 thereof simultaneously;

6) current traversal line is I type, when descending connecting line is multistage II type, with current that of a little corresponding another end points n=2 of traveling through in traversal II molded line, deletes all the other II molded line simultaneously.When descending connecting line is multistage type III, with current that of a little corresponding another end points n=2 of traveling through in traversal type III line, delete all the other type III lines simultaneously.

Described residue detection really refers to, according to actual processing, judges there is residual position in cutter rail by calculating.The general residual turning appearing at cutter rail, and be positioned at the Delta Region between two row cutter rails, determination methods is as follows:

1) all I molded line are sorted, travel through from Article 1, judge to be adjacent between the corresponding end points of I molded line whether have line, using without two-end-point spacing d corresponding to line as the current attribute traveling through I molded line;

2) according to sagging milling feature, general residual appear between two row cutter rails and to be in the Delta Region at turning, according to equal space line create-rule, when meeting following condition, remnants can be left between two row cutter rails $d>2\×\sqrt{{(\frac{\mathrm{TD}}{2}-\mathrm{TCR})}^2-{[\mathrm{Offset}2-(\frac{\mathrm{TD}}{2}-\mathrm{TCR})]}^2},$ (x=1 or 2), will meet the portion markings of this condition for residual position.

Described is carrying out the optimization process of cutter rail to residual position after residue detection, refers to that concrete grammar is as follows by inserting new line segment in the position judging to remain to solve residue problem:

1) supplementary cutter rail unit can be determined according to covering cutter rail requirement of sinking, and judge whether remaining area distance d ' is greater than supplementary cutter rail unit width, if then continue to increase and supplement cutter rail unit until d ' is less than single supplementary cutter rail width, then carry out following judgement:

(1) if be less than minimum cut wide; cutter rail supplement terminate;

(2) minimumly cutting wide if be greater than, supplementing finally supplementing cutter rail end points end points corresponding to the I molded line cutter rail that has been connected.

2) by the I molded line corresponding to all supplementary cutter rail replacements, complete cutter rail and supplement, using the final cutter rail of the cutter rail after circular cutter path and residual treatment as undercut nature.

The invention has the beneficial effects as follows:

The present invention is that skin part numerical control milling provides effective knife rail generating method, especially can be applied to the cutter orbit making of covering mirror image milling method, have counting yield high, accuracy is high, the advantage that applicability is strong, can alleviate the programing work amount of engineering staff greatly.

Accompanying drawing explanation

Fig. 1 is aircraft skin milling highly-efficient processing track automatic generation method process flow diagram of the present invention;

Fig. 2 is aircraft skin and typical undercut nature schematic diagram, and A is Typical Aircraft covering class part, and B is typical undercut nature partial enlarged view, B _tfor sagging end face, B _bfor sagging bottom surface, B _bCfor the face, base angle of sinking;

Fig. 3 is that the analysis of undercut nature geometric attribute and generation strategy are determined, CR is base angle radius, and R is Internal periphery concave edge least radius, r ₁for the covering radius-of-curvature along cross direction, r ₂for the covering radius-of-curvature along check mark direction, L _palfor the Internal periphery sideline parallel with optimum machine direction class;

Fig. 4 is that common sagging equal space line generates schematic diagram;

Fig. 5 is that the complicated equal space line that sink generates schematic diagram;

Fig. 6 is equal space line connection diagram, wherein (1)-(6) situation that is equal space line concatenate rule, and TPL is the final connection of equal space line;

Fig. 7 is cutter rail optimization process schematic diagram, and dotted line is shown as residual region, and Step1,2,3 is for increasing cutter rail step, and a judges signal for residual, and b is cutter rail after residual optimization;

Fig. 8 is final cutter rail schematic diagram, and wherein a is common sagging cutter rail, and b is the complicated cutter rail that sink, and c is the sagging cutter rail needing to carry out residual treatment.

Fig. 9 is embodiment of the present invention characteristic recognition method process flow diagram.

Embodiment

Here is described in detail to technical scheme of the present invention by reference to the accompanying drawings.

A kind of aircraft skin milling highly-efficient processing track automatic generation method, as shown in figures 1-8.Covering sink and mainly comprises sagging bottom surface B _b, sink face, base angle B _bCwith sagging end face B _t, its cutter rail is typically chosen in bottom surface and generates, and add and carry out feed along the line along bottom surface man-hour, the strategy of current cutter-contact point normal direction elected as by cutter shaft, and it is cutter rail along the line, and its generation method is as follows:

1. obtain the geometric element of sagging vallecular cavity feature to be processed, and analyze its profile convex-concave feature and based on sagging bottom surface curvature characteristic, process tool, the preferably cutter orbit making such as machine direction and cutting width strategy is determined in conjunction with operation resource storehouse, as shown in Figure 3, specific as follows;

1) determine preferred machine direction, the length that the general cutter rail sunk should be tried one's best along the direction that Curvature varying is less, the continuous swing that price is cutter shaft can be reduced like this, improve working (machining) efficiency, as shown in Figure 3, r ₂be greater than r ₁, therefore should by direction of checking the number in figure as preferred machine direction;

2) after preferred orientations is determined, consider that covering has the characteristic of single, double curvature, extract with the similar parallel outline line of preferred machine direction, as equidistant direction class parallel lines, and record its number L _pal;

3) selection of cutter, is mainly effective radius of clean-up R ' and the cutter base angle cr of cutter, need meets R ' <R, cr<CR, and according to actual production demand and tool magazine resource, select rational tool type;

4) scope of cutting width, the scope of cutting width CW is determined as follows:

The lower limit of CW is wherein d is the safe handling distance that ultrasonic thickness test device is reserved, and in this example, d is set to 3mm.

The upper limit of CW is ${\mathrm{CW}}_{\max }=2\&times;\sqrt{{(\frac{\mathrm{TD}}{2}-\mathrm{TCR})}^2-d^2}$

Such as adopt cutter TD=25mm, the nose of an ox cutter of base angle TCR=4mm, cuts wide CW and is limited to 11.5-15.9mm up and down.

Tentatively can be determined the processing scheme of sagging milling by above several step, prepare for equal space line generates.

2., according to equal space line create-rule, according to undercut nature geometric element geometry cutter orbit making strategy, automatically generate three class equal space lines, as shown in Figure 4,5, specific as follows;

For equidistant direction class parallel lines L _palwhen the number of=2 is 2, sink for typical case is common, as shown in Figure 4, its equal space line generation method is as follows:

1) will sink outline line L _contto sagging internal blas Offset1 distance, as the cutter rail of the final ring partial application of sagging milling, and stored in L _{cont_Offset1}, wherein i.e. effective radius of clean-up value of cutter;

2) the outline line L after skew is found _{cont_Offset1}in with L _palcorresponding two, calculate the maximum distance D along bottom surface of sinking between two lines, prepare for next step equal space line generates;

3) by L _{cont_Offset1}in each line continue to sagging internal blas Offset2 distance, Offset2=CW _min, each line segment after skew is stored in L _{cont_Offset2}in, and find corresponding to L _paltwo line segments, stored in LineI, and by wherein relatively short that, be designated as OffsetLine, by L _{cont_Offset2}middle class circular arc line segment is stored in LineII, and its balance class straight-line segment is stored in LineIII;

4) the equidistant distance Offset3 of OffsetLine and equidistant number N is calculated, round, and by N ' done add 1 or subtract 1 adjustment, meet ${\mathrm{CW}}_{\min }<\frac{D-2\&times;\mathrm{Offset}2}{N^{\&prime;}}<{\mathrm{CW}}_{\max },$ Then $\mathrm{Offset}3=\frac{D-2\&times;\mathrm{Offset}2}{N^{\&prime;}}\text{,}$ Each line two ends by OffsetLine with offset distance Offset3 equidistant N bar line, and are extended to L by N=N '-1 _{cont_Offset2}after stored in LineI ';

5) judge every bar line in LineI ' whether with the line segment intersection in LineII and LineIII list, intersect if having and the corresponding line segment segmentation in LineII and LineIII is interrupted, and replace stored in LineII and LineIII, simultaneously by the line segment in LineI ' stored in LineI.

For equidistant direction class parallel lines number L _palduring >2, for complexity is sunk, its equidistant rule is sagging slightly different, as shown in Figure 5, specific as follows from common:

1) will sink outline line L _contto sagging internal blas Offset1 distance, as the cutter rail of the final ring partial application of sagging milling, and stored in L _{cont_Offset1}, wherein i.e. effective radius of clean-up value of cutter;

2) by L _{cont_Offset1}middle removing is by L _palthe line segment that skew generates, all the other each lines continue to sagging internal blas Offset2 distance, Offset2=CW _min, by wherein class circular arc line segment is stored in LineII, its balance class straight-line segment is stored in LineIII;

3) by L _palby sorting from high to low, and by L _palpart between every two is divided into a region S _ij, calculate two L respectively _palalong the maximum distance D of bottom surface of sinking between class parallel lines _ij, i, j correspond to two L _palclass parallel lines with and carry out two kinds of equal space line generation strategies according to the concavity of profile;

4) when with between region sagging inner time, claim current region S _ijfor recessed region, incite somebody to action a wherein shorter equidistant limit of conduct, calculate its equidistant distance Offset3 _ijand equidistant number N _ij, round, if N _ij' for odd number done add 1 or subtract 1 adjustment, meet simultaneously ${\mathrm{CW}}_{\min }<\frac{D_{\mathrm{ij}}}{N_{\mathrm{ij}}^{\&prime;}}<{\mathrm{CW}}_{\max },$ Then ${\mathrm{Offset}3}_{\mathrm{ij}}=\frac{D_{\mathrm{ij}}}{N_{\mathrm{ij}}^{\&prime;}}\text{,}$ N _ij=N _ij'-1, by equidistant limit with offset distance Offset3 _ijequidistant N _ijbar line, and each line two ends are extended to L _{cont_Offset2}after stored in LineI;

5) when with between region sagging outside time, claim current region S _ijfor convex domain, the place uniquely different from recessed region is that its equal space line needs to ensure to generate in sagging inside, and by two with extend, will inner part of sinking be positioned at equally stored in LineI;

6) judge every bar line in LineI whether with the line segment intersection in LineII and LineIII list, intersect if having and the corresponding line segment segmentation in LineII and LineIII interrupted, and replace stored in LineII and LineIII.

According to above step, sagging inner three class equal space lines are all generated.

3., according to equal space line concatenate rule, three class equal space line head and the tail are connected into a curve, as the cutter rail of covering milling highly-efficient processing, as shown in Figure 6, specific as follows;

1) by the every bar line in three class equal space lines, increase the attribute n of two end points, n represents the number of current endpoint place equal space line;

2) sink for each, to get in LineI a line at most edge, be designated as LI ₁, an optional one end points LI _1-1start, to another end points LI _1-2advance, now LI ₁for current traversal line, LI _1-2for current traversal point, simultaneously will with LI _1-1the non-LineI molded line be connected is deleted, and the rule of deletion is, delete line that this end points is connected and become n=2 to connect line, as shown in phantom in Figure 6;

3) by current traversal line stored in TPL, and continue traversal, traversal rule is as follows:

If current traversal point n=2, then direct using coupled line segment as next traversal line, continue traversal;

If current traversal point n=3, then continue traversal according to the following rules:

(1) current traversal line is that LineI type is abbreviated as I type, and when descending connecting line is II, type III, traversal type III line, deletes the connecting line of corresponding II molded line and n=2 thereof simultaneously;

(2) current traversal line is II type, and when descending connecting line is I, type III, traversal I molded line, deletes the connecting line of corresponding type III line and n=2 thereof simultaneously;

(3) current traversal line is II type, and when descending connecting line is I, II type, traversal I molded line, deletes the connecting line of corresponding II molded line and n=2 thereof simultaneously;

(4) current traversal line is type III, and when descending connecting line is I, II type, traversal I molded line, deletes the connecting line of corresponding II molded line and n=2 thereof simultaneously;

(5) current traversal line is type III, and when descending connecting line is I, type III, traversal I molded line, deletes the connecting line of corresponding type III line and n=2 thereof simultaneously;

(6) current traversal line is I type, when descending connecting line is multistage II type, with current that of a little corresponding another end points n=2 of traveling through in traversal II molded line, deletes all the other II molded line simultaneously.When descending connecting line is multistage type III, with current that of a little corresponding another end points n=2 of traveling through in traversal type III line, delete all the other type III lines simultaneously.

According to above-mentioned rule, traversal, until LineI the last item line, by it stored in TPL, completes equal space line and connects.Now in TPL wired using preliminary as sagging Milling Process track.

4., by residue detection and the optimization process of cutter rail, ensure that cutter rail is applicable to all kinds of undercut nature of covering.

Because cutter rail is cut wide comparatively large, likely there will be between the row cutter rail of turning two and remain as shown in Figure 7, process can be optimized to existing cutter rail by the following method for this situation:

1) first need to lock residual position, according to actual processing, the general residual turning appearing at cutter rail, and the Delta Region between two row cutter rails, as shown in Figure 7, determination methods is as follows:

(1) all I molded line are first extracted, from an I at most edge _istart, calculate its I molded line I adjacent with next _i+1the distance d of two corresponding end points _i1and d _i2, judge whether have II type or type III line to be connected between two groups of corresponding end points, if not using the distance of correspondence as I _ian attribute, as d in Fig. 7 ₂₁shown in, until I _i+1for the last item in I molded line;

(2) according to equal space line create-rule, between two row cutter rails, whether Delta Region has to remain has relation as follows with Offset2:

When $d_{\mathrm{ix}}>2\&times;\sqrt{{(\frac{\mathrm{TD}}{2}-\mathrm{TCR})}^2-{[\mathrm{Offset}2-(\frac{\mathrm{TD}}{2}-\mathrm{TCR})]}^2},$ Time (x=1 or 2), can stay residual in Delta Region, region as shown in phantom in Figure 7, otherwise by d _ixbe designated as zero.

2) mode by increasing cutter rail in Delta Region is eliminated residual, for d _ixnon-vanishing situation, as shown in Figure 7, concrete grammar is as follows:

(1) by d _ixcorresponding two-end-point is designated as P _iand P _i+1, correspond respectively to I _iand I _i+1, calculate I _iand I _i+1length, longer is designated as I _lanother is designated as I _s, corresponding end points is designated as P _land P _s, and calculate line segment P _sp _lwith I _lbetween angle theta.

(2) by P _sedge offset distance CW _min, generate some P _l1, cross P _l1do perpendicular to I _lstraight line, straight line and I _lmeet at a P _l2, by P _l2edge offset distance CW _min, generate some P _l3, cross P _l3do perpendicular to I _lstraight line, straight line and line segment P _sp _lmeet at a P _l4, along sinking, bottom surface generates line P _l1p _l2, P _l1p _l4, P _l3p _l4, and by I _lbe positioned at P _l2and P _l3between part cut away, by remaining I _land P _l1p _l2, P _l1p _l4, P _l3p _l4, engage, replace corresponding I molded line I _ior I _i+1, as Step1 in Fig. 7,2, shown in 3 processes.

(3) P is calculated _l4to P _sdistance d ', and carry out following steps:

If 1. d '≤CW _minthen circulate end, carries out (4);

If 2. then by P _l3edge offset distance CW _min, generate some P _l5, cross P _l5do perpendicular to I _lstraight line, straight line and line segment P _sp _lmeet at a P _l6, along sinking, bottom surface generates line P _l5p _l6, P _l6p _l, and by I _lbe positioned at P _l5and P _lbetween part cut away, by remaining I _land P _l5p _l6, P _l6p _lengage, replace corresponding I molded line I _ior I _i+1, and carry out (4);

If 3. then by P _l4replace P _s, empty P _l1, P _l2, P _l3, P _l4rear continuation circulation step (2) (3);

(4) complete Delta Region and increase the optimization of cutter rail, as shown in b in Fig. 7, eliminate residual.

5. final cutter orbit making, joins end to end by the TPL after optimization process, after head and the tail point place each prolongation safe distance dis, as the final cutter rail of sagging processing, as shown in a, b, c in Fig. 8.

The brown feature identification of the present invention can adopt existing similar techniques to be realized, and the method shown in Fig. 9 also can be adopted to be realized, and in Fig. 9, the recognition methods of aircraft skin part feature comprises the following steps:

The first, analysis of aircraft stressed-skin construction feature and processing characteristics, define all kinds of covering machining feature;

The second, aircraft skin part pre-seted and builds ring property figure and holographic attribute face edge graph, pre-seting and mainly comprise: setting up Cutter coordinate system, selected reverse side identified surface and part model input; Define the seed face of all kinds of covering machining feature, search for the seed face of each category feature based on ring property figure and holographic attribute face edge graph;

3rd, process is optimized to the seed face with broken, then searches for based on reverse side identified surface, seed face and expansion rule, search out all geometric elements of each category feature, construct covering machining feature;

4th, extract all kinds of characteristic information, obtain feature recognition result.

Of the present invention by analysis of aircraft skin part design feature and processing characteristics, the geometrical body with process similarity and geological information is defined as covering machining feature and comprises sagging, the logical window of definition, hole and contour feature.Undercut nature is the shallow slot on covering, mainly comprises end face, face, base angle and bottom surface, the bottom surface of undercut nature is defined as the seed face of undercut nature; Logical window feature is position covering needing adopt Milling Process milling to wear, show as the manhole of diameter comparatively large (being usually greater than 20mm) or irregular hole in shape, mainly comprise wall, end face and bottom surface, the bottom surface of logical window feature is defined as the seed face of logical window feature; Hole characteristic covering needs adopt drilling to process the position drilled through, show as the manhole of diameter less (being usually less than or equal to 20mm) in shape, mainly comprise wall, end face and bottom surface, the bottom surface of hole characteristic is defined as the seed face of hole characteristic; Contour feature is the theoretical profile border of skin part, is used as the guide line of trimming programming, mainly comprises contoured surface, reverse side identified surface is defined as the seed face of profile.

The basis for selecting of described reverse side identified surface is: definition to be processed of skin part is front, and the face of vis-a-vis is reverse side, and any one face in covering reverse side chosen is as reverse side identified surface.

The described seed face searching for each category feature based on ring property figure and holographic attribute face edge graph refers to based on ring property figure and holographic attribute face edge graph, analyze ring property and the topological connection relation in face simultaneously, expand out meet all kinds of feature seed face ring property and topological connection relation feature face as the seed face of each category feature.Ring property figure refers to the ring property had by analysis face, constructs ring property figure, and ring property mainly refers to or without inner ring, has several inner ring, each inner ring has the characteristics such as how many inner ring limits respectively.

Described first whether to be connected according to curved surface when process is optimized to broken face, curvature whether continuously and the whether identical Rule of judgment of thickness, search out the curved surface met the demands, broken is considered as by there being the curved surface of associated relation, be optimized process, and form complete feature to replace original broken region feature, ensure the accuracy of undercut nature identification.

First described undercut nature finds all fronts according to reverse side identified surface when building, expand rule traversal front according to seed face of sinking and obtain correct sagging seed face, seed face expansion of sinking is regular: the front of definition containing inner ring is intermediate surface, will only containing outer annular edge front and and and disjunct of intermediate surface expand for sink bottom surface, correct face, base angle is found in seed face according to sinking, and correct sagging end face is found in the sagging face, base angle of recycling.The required undercut nature information spinner extracted will comprise: the numbering of sinking, thickness, bottom surface, face, base angle and end face.

First described logical window and hole characteristic find all reverse side according to reverse side identified surface when building, and obtains curved surface with inner ring limit as the seed face of logical window feature and hole characteristic by traversal reverse side.Wherein, inner ring limit quantity is greater than the reverse side of 2 or inner ring limit quantity equals 2 and the reverse side that diameter is greater than 20mm is expanded as logical window seed face; Inner ring limit quantity is equaled 2 and the reverse side that diameter is less than or equal to 20mm is expanded as seed face, hole.Find correct wall according to seed face again, then find correct end face according to wall.The required logical window characteristic information extracted mainly comprises: the numbering of logical window, the logical window degree of depth, bottom surface, wall and end face; The required hole characteristic information spinner extracted will comprise: axial, accuracy class, the tolerance in the numbering in hole, bottom surface, wall, end face, bore dia, hole depth, hole site, hole.

First described contour feature finds all reverse side according to profile seed face when building, more all faces that search is adjacent with reverse side, obtains all sides, more from the side in remove the wall of hole and logical window, namely obtain all contoured surfaces.The required contour feature information spinner extracted will comprise: profile numbering, contoured surface, accuracy class.

The part that the present invention does not relate to prior art that maybe can adopt same as the prior art is realized.

Claims (8)

1. an aircraft skin milling highly-efficient processing track automatic generation method, is characterized in that it comprises the following steps:

First, obtain the geometric element of undercut nature to be processed, determine cutter orbit making strategy in conjunction with operation resource storehouse;

Secondly, according to undercut nature geometric element and cutter orbit making strategy, adopt the mode of biased outline line to generate equal space line, will treat that biased line segment is divided three classes by its characteristic, according to equal space line create-rule, automatically generate all kinds of equal space line;

3rd, according to equal space line concatenate rule, by the head and the tail connection in an orderly manner of three class equal space lines, form a curve, as the cutter rail of covering milling highly-efficient processing;

4th, by carrying out residue detection and the optimization process of cutter rail to existing cutter rail, ensureing the cutter rail noresidue generated, and being applicable to all kinds of undercut nature of covering.

2. method according to claim 1, described in it is characterized in that, stationary knife rail generation strategy refers to really, by analyzing sagging silhouette edge convex-concave feature and based on sagging bottom surface curvature characteristic, determining process tool, preferably machine direction and cutting width in conjunction with operation resource storehouse:

1) process tool is determined, by analyzing the concavity of undercut nature silhouette edge, calculate the minimum profile curvature radius of concave edge, as the least radius limits value of cutter, analyze the radius-of-curvature in face, undercut nature base angle simultaneously, as cutter base angle radius reference value, in operation resource storehouse, choose the cutter that one or more are suitable;

2) preferably machine direction is determined, because covering milling of sinking adopts and cuts along the cutter shaft of bottom surface normal direction, consider for Machine kinematics, significantly pivot angle change should be reduced for five-axis linkage machine tools work in-process as far as possible, therefore the direction choosing covering Curvature varying minimum processes, namely increase the cutter rail length in this direction, by analyzing the Curvature varying of sagging silhouette edge, be preferred machine direction with the limit that radius-of-curvature is maximum as far as possible;

3) after cutter and preferred orientations are determined, determine that the scope of cutting width CW is as follows:

The lower limit of cutting width CW is wherein d is the safe handling distance that ultrasonic thickness test device is reserved, and TD is tool diameter, and TCR is cutter base angle radius;

The upper limit of cutting width CW is ${\mathrm{CW}}_{\max }=2\&times;\sqrt{{(\frac{\mathrm{TD}}{2}-\mathrm{TCR})}^2-d^2}.$

3. method according to claim 1, it is characterized in that described foundation equal space line create-rule and undercut nature geometric element generate equal space line, generation foundation using equal space line as final cutter rail, wherein equal space line is divided into three types, first is the I class equal space line parallel with machine direction, second be with machine direction nonparallel class circular arc line as II class equal space line, the 3rd be with machine direction nonparallel class straight line as III class equal space line.

4. method according to claim 1, is characterized in that described automatically generate equal space line based on three class equal space line create-rules and referring to:

First extract and the approximately parallel profile sideline of machine direction, deposit in L _pal, less parallel is here because covering may for hyperbolicity part, and two corresponding sidelines can not be completely parallel, carries out following steps after extraction:

1) for L _palnumber when being 2, sink for typical case is common, first its equal space line generation method is biased all profile borders with the effective radius of clean-up of cutter, as the final cutter rail L along profile ring cutting _{cont_Offset1}; Secondly by L _{cont_Offset1}in with L _palcorresponding limit as I class equal space line, and according to maximum distance between both sides and cut wide region, to L _palmiddle sideline is biased, and obtains all I class equal space lines; 3rd by L _{cont_Offset1}middle remaining sides is all inwardly biased cuts wide lower limit, and using wherein circular arc class as II class equal space line, the conduct III class equal space line of class straight line; I class equal space line and II class equal space line and III class equal space line to carry out crossingly interrupting process by the 4th, obtain final all kinds of equal space line;

2) for L _palnumber when being greater than 2, for complexity is sunk, its equal space line generation method is first same is biased all profile borders with the effective radius of clean-up of cutter, as the final cutter rail L along profile ring cutting _{cont_Offset1}; Secondly by L _{cont_Offset1}in with L _palcorresponding limit is extracted, and the region between every two adjacent edges is divided into convex, recessed two kinds of situations, for recessed region by its I class line equidistant odd number bar line, corresponding convex domain by its I class equal space line equidistant even numbers bar line, and using all equal space lines as I class equal space line; 3rd by L _{cont_Offset1}middle remaining sides is all inwardly biased cuts wide lower limit, and using wherein circular arc class as II class equal space line, the conduct III class equal space line of class straight line; In 4th each region, I class equal space line and II class equal space line and III class equal space line are carried out crossingly interrupting process, obtain final all kinds of equal space line.

5. method according to claim 1, is characterized in that described according to equal space line concatenate rule, by three class equal space lines in an orderly manner head and the tail connect, the cutter rail forming the cutter rail of covering milling highly-efficient processing refers to:

1) first by the every bar line in three class equal space lines, increase the attribute n of two end points, n represents the number of current endpoint place equal space line;

2) sink for each, traversal from an I class equal space line at most edge, judge the n attribute of current traversal end points, if n=2, directly traverse connected line, if n>2, carry out selection traversal according to concatenate rule, and delete redundancy limit, finally obtain by the end to end complete curve of all kinds of line, as initial manufacture track.

6. method according to claim 5, is characterized in that described carry out selection traversal according to concatenate rule and referring to:

If current traversal point n=3, then continue traversal according to the following rules:

1) current traversal line is the equidistant line style of I class (hereinafter referred to as I type), when descending connecting line is II class equal space line (hereinafter referred to as II type), III class equal space line (hereinafter referred to as type III), traversal type III line, deletes the connecting line of corresponding II molded line and n=2 thereof simultaneously;

2) current traversal line is II type, and when descending connecting line is I, type III, traversal I molded line, deletes the connecting line of corresponding type III line and n=2 thereof simultaneously;

3) current traversal line is II type, and when descending connecting line is I, II type, traversal I molded line, deletes the connecting line of corresponding II molded line and n=2 thereof simultaneously;

4) current traversal line is type III, and when descending connecting line is I, II type, traversal I molded line, deletes the connecting line of corresponding II molded line and n=2 thereof simultaneously;

5) current traversal line is type III, and when descending connecting line is I, type III, traversal I molded line, deletes the connecting line of corresponding type III line and n=2 thereof simultaneously;

6) current traversal line is I type, when descending connecting line is multistage II type, with current that of a little corresponding another end points n=2 of traveling through in traversal II molded line, deletes all the other II molded line simultaneously.When descending connecting line is multistage type III, with current that of a little corresponding another end points n=2 of traveling through in traversal type III line, delete all the other type III lines simultaneously.

7. method according to claim 1, it is characterized in that described residue detection refers to, according to actual processing, judging there is residual position in cutter rail by calculating, when residual appear at the turning of cutter rail and be positioned at the Delta Region between two row cutter rails time, its determination methods is as follows:

1) all I molded line are sorted, travel through from Article 1, judge to be adjacent between the corresponding end points of I molded line whether have line, using without two-end-point spacing d corresponding to line as the current attribute traveling through I molded line;

2) according to sagging milling feature, residual appear between two row cutter rails and to be in the Delta Region at turning, according to equal space line create-rule, when meeting following condition, remnants can be left between two row cutter rails:

$d>2\&times;\sqrt{{(\frac{\mathrm{TD}}{2}-\mathrm{TCR})}^2-{[\mathrm{Offset}2-(\frac{\mathrm{TD}}{2}-\mathrm{TCR})]}^2},$ (x=1 or 2), will meet the portion markings of this condition for residual position.

8. method according to claim 1, is characterized in that described after residue detection, carrying out the optimization process of cutter rail to residual position, refers to solve by inserting new line segment in the position judging to remain, and concrete grammar is as follows:

1) supplementary cutter rail unit is determined according to covering cutter rail requirement of sinking, and judge whether remaining area distance d ' is greater than supplementary cutter rail unit width, if then continue to increase and supplement cutter rail unit until d ' is less than single supplementary cutter rail width, then carry out following judgement:

(1) if be less than minimum cut wide; cutter rail supplement terminate;

(2) minimumly cutting wide if be greater than, supplementing finally supplementing cutter rail end points end points corresponding to the I molded line cutter rail that has been connected;

2) by the I molded line corresponding to all supplementary cutter rail replacements, complete cutter rail and supplement, using the final cutter rail of the cutter rail after circular cutter path and residual treatment as undercut nature.