CN104820401A - Aircraft structural part rib feature recognition method based on constrained Delaunay triangulation - Google Patents
Aircraft structural part rib feature recognition method based on constrained Delaunay triangulation Download PDFInfo
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
- G05B19/4097—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by using design data to control NC machines, e.g. CAD/CAM
Abstract
The invention provides an aircraft structural part rib feature recognition method based on constrained Delaunay triangulation. The overall process of the method comprises the steps of (1) identifying a generalized web surface, (2) dispersing generalized web surface boundary and carrying out constrained Delaunay triangulation on the generalized web surface, (3) distinguishing the flat top rib surface and the web surface in the generalized web surface, (4) extracting and modifying the central axis of the flat top rib surface, (5) building a flat top surface split sub-feature, and (6) identify and building an oblique rib. Practice has proved that the method has the advantages of high recognition efficiency, fast speed and small occupation space and can be used to identify and build the aircraft structural part rib feature so as to improve the efficiency of fast NC programming and significantly reduce the workload of technicians.
Description
Technical field
The present invention relates to a kind of plane structural part rib characteristic identification method based on Constrained Delaunay triangulation, for the quick establishment of aircraft complex structural member numerical control program, for specialized, that intelligent CAD/CAPP/CAM integrated system " the quick NC Programming System of aircraft structure " provides automatic feature recognition related data, belong to aircraft digital Technology of NC Programming field.
Background technology
In all kinds of common aircraft structure, muscle feature (abbreviation muscle) is extensively present among interior appearance profile, vallecular cavity, or exists as boss muscle separately.Its Main Function is the weight alleviating structural member, strengthens the intensity etc. of key position.The numerical control programming of muscle is loaded down with trivial details and easily make mistakes.Therefore improving numerical control programming efficiency is improve the key of this kind of aircraft structure working (machining) efficiency.Address this problem the information transmission first having needed CAD system to CAM, CAPP system, set up the mapping relations between the solid model of part and machining feature, processing technology, thus provide data message for the fast automatic programming of aircraft structure.And feature identification technique is the ideal interface realizing CAD/CAM/CAPP three's organic integration.Namely be the primary prerequisite realizing numerical control programming, feature machining to accurate, the quick identification of different characteristic.
Summary of the invention
For solving the problem, the present invention proposes the plane structural part rib characteristic identification method based on Constrained Delaunay triangulation, and the method can effectively identify with the muscle feature in the aircraft structure of in small, broken bits.
The object of the invention is to be achieved through the following technical solutions:
Based on the plane structural part rib characteristic identification method of Constrained Delaunay triangulation, the key step that the method realizes has: 1) identify broad sense web surface; 2) discrete generalized web surface border Constrained Delaunay triangulation is carried out to broad sense web surface; 3) the flat-topped rib face in broad sense web surface and web surface is distinguished; 4) extract and revise the axis in flat-topped rib face; 5) build flat-topped rib face and split subcharacter; 6) identify and build diagonal bar.
Described step 1) identify broad sense web surface, comprise the identification of (1) surface level; (2) identification on the face of cylinder;
First the identification of described (1) surface level, namely identify the hither plane in Nurbus curved surface, and the in vitro method extracting each plane, to N, calculates the angle theta of itself and process side coordinate system Z axis, judges to satisfy condition
hither plane be forward surface level;
The identification on described (2) face of cylinder.Namely first identify the face of cylinder in Nurbus curved surface, extract the axis on each face of cylinder, the angle calculating itself and process side coordinate system Z axis is θ, and to the plane of θ=pi/2, fluted column face is end disc; Protruding cylinder surface is transition face.
Described step 2) discrete generalized web surface border Constrained Delaunay triangulation is carried out to broad sense web surface, comprise (1) discrete generalized web surface border; (2) Constrained Delaunay triangulation is carried out to broad sense web surface;
Described (1) discrete generalized web surface border, namely ensures that the distance between the adjacent pass point in border is less than the mean breadth w of flat-topped rib;
Described (2) carry out Constrained Delaunay triangulation to broad sense web surface, namely utilize insertion algorithm to treat divided region and carry out Delaunay triangulation, and are rejected by the triangle of center of gravity not in polygon.
Described step 3) flat-topped rib face in difference broad sense web surface and web surface, carry out according to definition 1 Sum fanction 1;
Described definition 1: set a forward surface level under Cutter coordinate system as f
h, Delaunay (f
h) represent f
hperform Constrained Delaunay triangulation, { △
i(i=1,2,3 ... n) be the triangle collection obtained after subdivision, if △
ithe length on every bar limit be all less than 1.5w, then △
ibe called specification triangle; If △
iin the length at least two limits be greater than 1.5w, then △
ibe called abnormal triangle;
Described rule 1, the distinguishing rule of flat-topped rib face and web surface: establish { △
i(i=1,2,3 ..., n) be surface level f
hperform Delaunay (f
h) after the triangle collection that obtains, { △
j(j=0,1,2,3 ... k, k≤n) be { △
iin abnormal triangle sets.If k is > [n/3]+1, then f
hfor web surface, otherwise f
hfor flat-topped rib face.
Described step 4) extract and revise the axis in flat-topped rib face, comprise (1) and extract axis, flat-topped rib face; (2) axis is merged;
Axis, flat-topped rib face is extracted in described (1), namely utilizes the result of Delaunay triangulation to carry out: to the triangle after splitting, only have have adjacent leg-of-mutton be edge triangles △
e, both sides have adjacent leg-of-mutton for intermediate triangle △
m, three limits have adjacent leg-of-mutton for inside triangle △
i, connect the axis network that these three kinds of leg-of-mutton axis can obtain flat-topped rib face.Wherein, limit triangle belonging to Polygonal Boundary is called limit, boundary, two adjacent leg-of-mutton common edge are called adjacent side, then the axis of edge triangles is the line of adjacent side mid point and two limit, boundary intersection points, the axis of intermediate triangle is the line of two adjacent side mid points, and the axis of inside triangle is the line of its center of gravity and three adjacent side mid points;
Described (2) merge axis, are namely first disconnected at the center of gravity place of inside triangle all axis and become independently line segment, then utilize rule 2 to merge;
Described rule 2, namely axis merges rule: after establishing a certain flat-topped rib face f to carry out Constrained Delaunay triangulation,
(n>=1), to △
ii, the axis associated by it is
(m=3), if S
ijat △
iithe adjacent triangle at place is △
ior △
e, then S is deleted
ij; Otherwise, retain S
ij, and get along its curvilinear inner move towards cut vow V
ij, for △
iiany two axis S of association
ij, S
ik(1≤j, k≤3), V is vowed in cutting of its association
ijwith V
ikbetween maximum angle θ
ijk=Max (<V
ij, V
ik>), if θ
ijk>=θ
m(θ
mfor angle merges threshold value, maximumly get θ
m=π), then axis S
ijand S
ikcan merge.
Described step 5) build flat-topped rib face fractionation subcharacter, namely edge triangles and the limit, boundary thereof of every bar axis end is extracted, whether the adjacent surface judging limit, boundary is end disc type, if be then set to the end disc of current subcharacter, and extracts the adjacent surface tangent with disc at the bottom of this subcharacter; If not, then restrictor that adjacent surface is current subcharacter is set and preserves adjacent surface, using the search face as subcharacter association diagonal bar;
Described step 6) identify and build diagonal bar, namely the diagonal bar search face in flat-topped rib face is obtained, judge the machined surface type in each search face, extract oblique machined surface wherein, the interarea width in the search face of calculating, to the interarea meeting the wide threshold value of setting muscle, extract face of cylinder of its association as the transition face of diagonal bar or end disc, structure diagonal bar node, and the type (oblique top muscle or bent top muscle) of current diagonal bar is set according to the geometric type of interarea, according to interarea or end disc, extract the side wall surface of its association as restriction face, arranging current diagonal bar node is the child node that corresponding flat-topped rib face splits feature.
Beneficial effect of the present invention: the plane structural part rib characteristic identification method based on Constrained Delaunay triangulation that application the present invention proposes, flat-topped rib face can be identified from broad sense web surface according to the result of triangulation, and then extract and revise the axis in flat-topped rib face, finally identify and build the fractionation subcharacter in flat-topped rib face and the diagonal bar subcharacter of association thereof.Adopt and can identify rapidly and accurately in this way and the muscle feature built in aircraft structure, for the feature identification in automated programming process provides technical support.
Accompanying drawing explanation
Fig. 1 a nearly quadratic programming face recognition methods schematic diagram---curved surface to be identified
Fig. 1 b nearly quadratic programming face recognition methods schematic diagram---recognition methods
Fig. 2 a web surface triangulation
Fig. 2 b flat-topped rib face triangulation
The classification of Fig. 3 a Order Triangular Elements
The connected mode of the different Order Triangular Elements axis of Fig. 3 b tri-class
The axis that Fig. 4 decomposes
Fig. 5 a inside triangle and adjacent leg-of-mutton composite type---△
iaMP.AMp.Amp △
i
Fig. 5 b inside triangle and adjacent leg-of-mutton composite type---△
iaMP.AMp.Amp △
e
Fig. 5 c inside triangle and adjacent leg-of-mutton composite type---△
iaMP.AMp.Amp △
m
The merging of Fig. 6 axis
Embodiment
The present invention is based upon on CAD/CAM system platform, realizes a kind of method of the feature identification of aircraft structure muscle and structure.
Below in conjunction with accompanying drawing, embodiments of the invention are described in detail; the present embodiment implements under premised on invention technical scheme; give detailed embodiment and concrete implementation procedure, but protection scope of the present invention is not limited to following embodiment.
Step 1): identify broad sense web surface.First identify the hither plane in Nurbs curved surface type and the face of cylinder, then extract end disc and the transition face of all surface levels and muscle feature association to the angle with Z axis according to planar process, as shown in Figure 1.Specific as follows:
Known process precision ε
m, face f is Nurbs type, and its U is [p to parameter area
us, p
ue], V is [p to parameter area
vs, p
ve], respectively at p
us, (p
us+ p
ue)/2, p
ueu gets to parameter line c in place
us, c
um, c
ue; Similarly, respectively at p
vs, (p
vs+ p
ve)/2, p
vev gets to parameter line c in place
vs, c
vm, c
ve.Set up following hither plane recognition rule:
Rule 1 (hither plane identification) is if c
us, c
um, c
ue, c
vs, c
vm, c
vein at least five parameter lines be straight line, then f is hither plane.
After completing the identification of plane type, extract further the in vitro method of each plane to N, if the angle of itself and process side coordinate system Z axis is θ.If
Then this plane is forward surface level.
Rule 2 (identifications of the nearly face of cylinder) are if f one of meets the following conditions:
(1) c
us, c
um, c
uebe the circular arc that radius is identical, the center of circle does not overlap between two mutually, and c
vs, c
vm, c
vebe the straight line be parallel to each other;
(2) c
vs, c
vm, c
vebe the circular arc that radius is identical, the center of circle does not overlap between two mutually, and c
us, c
um, c
uebe the straight line be parallel to each other.Then f is the nearly face of cylinder.
After completing the identification of face of cylinder type, extract further the axis on each face of cylinder, if the angle of itself and process side coordinate system Z axis is θ.When θ=pi/2, judging face of cylinder concavity and convexity, if the face of cylinder is recessed, is then end disc; If the face of cylinder is convex, then it is transition face.
Step 2): Constrained Delaunay triangulation is also carried out to broad sense web surface in discrete generalized web surface border.Comprise (1) discrete generalized web surface border; (2) Constrained Delaunay triangulation is carried out to broad sense web surface.
Described (1) discrete generalized web surface border, namely ensure that the distance between the adjacent pass point in border is less than the mean breadth w of flat-topped rib, concrete grammar is:
For certain forward surface level f
hif its frontier point is { P
i, the coordinate under current coordinate system is (x
i, y
i), work as length | P
ip
i+1| >w (w is the mean breadth of flat-topped rib, can be rule of thumb presetting), then pass point { P
k, have:
wherein,
After further judgement encryption | P
ip
k| with | P
kp
i+1|, until the distance between adjacent pass point is less than w.
Described (2) carry out Constrained Delaunay triangulation to broad sense web surface, after namely obtaining pass point, will treat that divided region carries out Delaunay triangulation, and extract each barycenter oftriangle: P ((x
1+ x
2+ x
3)/3, (y
1+ y
2+ y
3)/3), judge P whether in polygon, the triangle of center of gravity not in polygon is rejected.Finally obtain the Delaunay triangulation result of boundary constraint, the triangular element after subdivision is Order Triangular Elements.
Step 3): the flat-topped rib face in difference broad sense web surface and web surface.Carry out according to definition 1 Sum fanction 3;
Described definition 1: set a forward surface level under Cutter coordinate system as f
h, Delaunay (f
h) represent f
hperform Constrained Delaunay triangulation, { △
i(i=1,2,3 ... n) be the triangle collection obtained after subdivision, if △
ithe length on every bar limit be all less than 1.5w, then △
ibe called specification triangle; If △
iin the length at least two limits be greater than 1.5w, then △
ibe called abnormal triangle;
Described rule 3, the distinguishing rule of flat-topped rib face and web surface: establish { △
i(i=1,2,3 ..., n) be surface level f
hperform Delaunay (f
h) after the triangle collection that obtains, { △
j(j=0,1,2,3 ... k, k≤n) be { △
iin abnormal triangle sets.If k is > [n/3]+1, then f
hfor web surface, otherwise f
hfor flat-topped rib face.
As shown in Figure 2, have Order Triangular Elements 34 in a figure, wherein specification triangle has 0,28, abnormal triangle, then this face is web surface; Have Order Triangular Elements 41 in b figure, wherein 38, specification triangle, 3, abnormal triangle, then this face is flat-topped rib face.
Step 4): extract and revise the axis in flat-topped rib face.Comprise (1) and extract axis, flat-topped rib face; (2) axis is merged.
Described (1) extracts axis, flat-topped rib face, first according to each Order Triangular Elements with its relation of adjacent Order Triangular Elements classify: only have have adjacent leg-of-mutton be edge triangles △
e, both sides have adjacent leg-of-mutton for intermediate triangle △
m, three limits have adjacent leg-of-mutton for inside triangle △
i.Connect the axis network that these three kinds of leg-of-mutton axis can obtain flat-topped rib face.Wherein, limit triangle belonging to Polygonal Boundary is limit, boundary, and two adjacent leg-of-mutton common edge are adjacent side, then △
ebe made up of Liang Tiao circle limit and an adjacent side, its axis is the line of adjacent side mid point and two limit, boundary intersection points; △
mbe made up of limit, a boundary and two adjacent sides, its axis is the line of two adjacent side mid points; △
ibe made up of three adjacent sides, its axis is the line of its center of gravity and three adjacent side mid points.Figure 3 shows that classification and the axis thereof of Order Triangular Elements.
Described (2) merge axis, first, by all axis at △
icenter of gravity place disconnect become independently line segment, as shown in Figure 4.According to this inside triangle the triangular type that adjoins, type of its combination may be △
iaMP.AMp.Amp △
i, △
iaMP.AMp.Amp △
m, △
iaMP.AMp.Amp △
e.Different composite types, takes different merging rules: △
iaMP.AMp.Amp △
ithe axis of type combination is only a point, is generally present in " right-angled intersection " mouth place, as shown in Figure 5 a, directly deletes this axis; △
iaMP.AMp.Amp △
ethe axis of type combination is a short line segment, is generally present in the prominence on border, as shown in Figure 5 b, directly deletes this axis; △
iaMP.AMp.Amp △
mthe axis of type combination, as shown in Figure 5 c, need first to carry out Effective judgement to this axis, the leg-of-mutton number namely associated by axis and length thereof judge that this axis is the need of merging.△ shown in Fig. 5 c
iaMP.AMp.Amp △
mthe axis of type combination only associates 2 triangles, and its length is less than the diameter of cutter, adds man-hour without the need to mending a cutter herein separately, therefore directly deletes.To effective axis, regularly 4 merge.
Described regular 4, the merging rule of axis: after establishing a certain flat-topped rib face f to carry out Constrained Delaunay triangulation,
(n>=1), to △
ii, the axis associated by it is
(m=3), if S
ijat △
iithe adjacent triangle at place is △
ior △
e, then S is deleted
ij; Otherwise, retain S
ij, and get along its curvilinear inner move towards cut vow V
ij, for △
iiany two axis S of association
ij, S
ik(1≤j, k≤3), V is vowed in cutting of its association
ijwith V
ikbetween maximum angle θ
ijk=Max (<V
ij, V
ik>), if θ
ijk>=θ
m(θ
mfor angle merges threshold value, maximumly get θ
m=π), then axis S
ijand S
ikcan merge.
T-shape flat-topped rib face in Fig. 6 is after constraint Delaunay triangulation network lattice subdivision, and its axis is at △
icenter of gravity place disconnect, utilize rule 4 known S
i1, S
i2between angle maximum, therefore S
i1, S
i2can merge.
Step 5): build flat-topped rib face and split subcharacter.Detailed process is as follows:
(1) extract the axis in current flat-topped rib face, structure splits characteristic node, and arranging its node type is flat-topped rib;
(2) △ of every bar axis first and last end is extracted
e;
(3) each △ is extracted
elimit, boundary;
(4) whether the adjacent surface judging limit, boundary is end disc type, if be then set to the end disc of current subcharacter, otherwise proceeds to (6);
(5) adjacent surface tangent with disc at the bottom of this subcharacter is extracted;
(6) restrictor that adjacent surface is current subcharacter is set and preserves adjacent surface, using the search face as subcharacter association diagonal bar.
Step 6): identify and build diagonal bar.Detailed process is as follows:
(1) the diagonal bar search face in flat-topped rib face is obtained;
(2) judge the machined surface type in each search face, extract oblique machined surface wherein;
(3) calculate the interarea width in search face, if the wide threshold value of the muscle meeting setting, continue to extract its face of cylinder that may associate as the transition face of diagonal bar or end disc, otherwise return (2);
(4) construct diagonal bar node, and the type (oblique top muscle or bent top muscle) of current diagonal bar is set according to the geometric type of interarea;
(5) according to interarea or end disc, the side wall surface of its association is extracted as restriction face;
(6) arranging current diagonal bar node is the child node that corresponding flat-topped rib face splits feature.
Claims (7)
1. based on the plane structural part rib characteristic identification method of Constrained Delaunay triangulation, it is characterized in that: the overall procedure that the method realizes is: 1) identify broad sense web surface; 2) discrete generalized web surface border Constrained Delaunay triangulation is carried out to broad sense web surface; 3) the flat-topped rib face in broad sense web surface and web surface is distinguished; 4) extract and revise the axis in flat-topped rib face; 5) build flat-topped rib face and split subcharacter; 6) identify and build diagonal bar.
2. based on the plane structural part rib characteristic identification method of Constrained Delaunay triangulation, it is characterized in that: described step 1) identify broad sense web surface, comprise the identification of (1) surface level; (2) identification on the face of cylinder;
First the identification of described (1) surface level, namely identify the hither plane in Nurbus curved surface, and the in vitro method extracting each plane, to N, calculates the angle theta of itself and process side coordinate system Z axis, judges to satisfy condition
hither plane be forward surface level;
First the identification on described (2) face of cylinder, namely identify the face of cylinder in Nurbus curved surface, extract the axis on each face of cylinder, and calculate the angle theta of itself and process side coordinate system Z axis, to the plane of θ=pi/2, fluted column face is end disc; Protruding cylinder surface is transition face.
3. based on the plane structural part rib characteristic identification method of Constrained Delaunay triangulation, it is characterized in that: described step 2) discrete generalized web surface border Constrained Delaunay triangulation is carried out to broad sense web surface, comprise (1) discrete generalized web surface border; (2) Constrained Delaunay triangulation is carried out to broad sense web surface;
Described (1) discrete generalized web surface border, namely ensures that the distance between the adjacent pass point in border is less than the mean breadth w of flat-topped rib;
Described (2) carry out Constrained Delaunay triangulation to broad sense web surface, namely utilize insertion algorithm to treat divided region and carry out Delaunay triangulation, and are rejected by the triangle of center of gravity not in polygon.
4. based on the plane structural part rib characteristic identification method of Constrained Delaunay triangulation, it is characterized in that: described step 3) flat-topped rib face in difference broad sense web surface and web surface, carry out according to definition 1 Sum fanction 1;
Described definition 1: set a forward surface level under Cutter coordinate system as f
h, Delaunay (f
h) represent f
hperform Constrained Delaunay triangulation, { △
i(i=1,2,3 ... n) be the triangle collection obtained after subdivision, if △
ithe length on every bar limit be all less than 1.5w, then △
ibe called specification triangle; If △
iin the length at least two limits be greater than 1.5w, then △
ibe called abnormal triangle;
Described rule 1, the distinguishing rule of flat-topped rib face and web surface: establish { △
i(i=1,2,3 ..., n) be surface level f
hperform Delaunay (f
h) after the triangle collection that obtains, { △
j(j=0,1,2,3 ... k, k≤n) be { △
iin abnormal triangle sets, if k > [n/3]+1, then f
hfor web surface, otherwise f
hfor flat-topped rib face.
5. based on the plane structural part rib characteristic identification method of Constrained Delaunay triangulation, it is characterized in that: described step 4) extract and revise the axis in flat-topped rib face, comprise (1) and extract axis, flat-topped rib face; (2) axis is merged;
Axis, flat-topped rib face is extracted in described (1), namely utilizes the result of Delaunay triangulation to carry out: to the triangle after splitting, only have have adjacent leg-of-mutton be edge triangles △
e, both sides have adjacent leg-of-mutton for intermediate triangle △
m, three limits have adjacent leg-of-mutton for inside triangle △
iconnect the axis network that these three kinds of leg-of-mutton axis can obtain flat-topped rib face, wherein, limit triangle belonging to Polygonal Boundary is called limit, boundary, two adjacent leg-of-mutton common edge are called adjacent side, then the axis of edge triangles is the line of adjacent side mid point and two limit, boundary intersection points, and the axis of intermediate triangle is the line of two adjacent side mid points, and the axis of inside triangle is the line of its center of gravity and three adjacent side mid points;
Described (2) merge axis, are namely first disconnected at the center of gravity place of inside triangle all axis and become independently line segment, then utilize rule 2 to merge;
Described rule 2, namely axis merges rule: after establishing a certain flat-topped rib face f to carry out Constrained Delaunay triangulation,
to △
ii, the axis associated by it is
if S
ijat △
iithe adjacent triangle at place is △
ior △
e, then S is deleted
ij; Otherwise, retain S
ij, and get along its curvilinear inner move towards cut vow V
ij, for △
iiany two axis S of association
ij, S
ik(1≤j, k≤3), V is vowed in cutting of its association
ijwith V
ikbetween maximum angle θ
ijk=Max (<V
ij, V
ik>), if θ
ijk>=θ
m(θ
mfor angle merges threshold value, maximumly get θ
m=π), then axis S
ijand S
ikcan merge.
6. based on the plane structural part rib characteristic identification method of Constrained Delaunay triangulation, it is characterized in that: described step 5) build flat-topped rib face fractionation subcharacter, namely edge triangles and the limit, boundary thereof of every bar axis end is extracted, whether the adjacent surface judging limit, boundary is end disc type, if be then set to the end disc of current subcharacter, and extract the adjacent surface tangent with disc at the bottom of this subcharacter; If not, then restrictor that adjacent surface is current subcharacter is set and preserves adjacent surface, using the search face as subcharacter association diagonal bar.
7. based on the plane structural part rib characteristic identification method of Constrained Delaunay triangulation, it is characterized in that: described step 6) identify and build diagonal bar, namely the diagonal bar search face in flat-topped rib face is obtained, judge the machined surface type in each search face, extract oblique machined surface wherein, the interarea width in the search face of calculating, to the interarea meeting the wide threshold value of setting muscle, extract face of cylinder of its association as the transition face of diagonal bar or end disc, structure diagonal bar node, and the type (oblique top muscle or bent top muscle) of current diagonal bar is set according to the geometric type of interarea, according to interarea or end disc, extract the side wall surface of its association as restriction face, arranging current diagonal bar node is the child node that corresponding flat-topped rib face splits feature.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105046020A (en) * | 2015-08-21 | 2015-11-11 | 北京航空航天大学 | Automatic identification and correction method used for broken surface defect of airplane complex structural component |
| CN108763757A (en) * | 2018-05-29 | 2018-11-06 | 沈阳飞机工业（集团）有限公司 | Plane top rib face numerical control knife rail generating method |
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