CN104239649A - Shape feature self-defining and recognition system - Google Patents

Abstract

The invention aims at solving the problems that types of recognizable shape features are limited, new shape features are difficult to add and the like of a CAPP (Computer-Aided Process Planning) or CAIP (Computer Assisted Index Program)system shape feature recognition method in the prior art, and provides a shape feature self-defining and recognition system. The shape feature self-defining and recognition system comprises a feature library for storing feature templates of various shape types, a feature manager for managing the feature templates in the feature library and a feature recognizer for recognizing shape features, is embedded in a mechanical part CAPP or CAIP system and provides feature recognition results to the CAPP or CAIP system. The shape feature self-defining and recognition system has the beneficial effects that under the condition that no change is made to the CAPP or CAIP system, the feature recognition range of the system can be conveniently expanded, the flexibility and the applicability of feature recognition are improved, the range of shape feature types recognizable by the CAPP or CAIP system is greatly expanded, and new shape features are easier to add.

Description

Self-defined and the recognition system of shape facility

Technical field

The present invention relates to the shape facility recognition technology in mechanical component CAPP CAPP and computer aided detection planning CAIP, be related specifically to the self-defined and recognition system of a kind of shape facility.

Background technology

Mechanical component processing and efficient, the high-quality active demand detected, promoted the development of mechanical component CAPP CAPP or computer aided detection planning CAIP technology.Shape facility recognition technology also experienced by significant progress as one of the gordian technique of CAPP and CAIP, at present existing numerous different technical method.As method (Gao S, the Shah JJ.Automatic recognition of interacting machining features based on minimal condition subgraph.Comput Aided Design.1998 based on figure; 30 (9): 727-39), based on method (the Woo Y.Fast cell-based decomposition and applications to solid modeling.Comput Aided Design.2003 that body decomposes; 35 (11): 969-77), based on method (Han J, Regli WC, the Brooks S.Hint-based reasoning for feature recognition:status report.Comput Aided Design.1998 of vestige; 30 (13): 1003-7) and mixing method (Sunil VB, Agarwal R, Pande SS.An approach to recognize interacting features from B-Rep CAD models of prismatic machined parts using a hybrid (graph and rule based) technique.Comput Ind.2010; 61 (7): 686-701) etc.But, these prior art shape facility recognition methodss are all that to be solidificated in CAPP or CAIP intrasystem, the shape facility type that system can identify just is determined completely after system development completes, to identify the shape facility of other type, then need to develop new program and change is made with the feature identification range of expanding system to system.Change CAPP or CAIP system then to need to pay larger manpower, financial resources and material resources.Obviously, prior art CAPP or CAIP system shape characteristic recognition method also exist the shape facility type that can identify limitation, increase new shape facility comparatively difficulty etc. problem.

Summary of the invention

The shape facility type that can identify existed for solving prior art CAPP or CAIP system shape characteristic recognition method has limitation, increases the problems such as new shape facility is comparatively difficult, and the present invention proposes the self-defined and recognition system of a kind of shape facility.Shape facility of the present invention is self-defined comprises feature database, Features Management device and feature identifier with recognition system, and embeds in mechanical component CAPP CAPP or computer aided detection planning CAIP, wherein,

Feature database is for storing the feature templates of various shape type, and described feature templates is used for carrying out standardization to shape facility and describes, and all types of feature templates has unified expression and file layout in feature database;

Features Management device is used for the feature templates in characteristics of management storehouse, comprises newly-built feature templates, amendment feature templates, query characteristics template and deletion feature templates;

Feature identifier is used for shape facility identification, and provides feature recognition result to CAPP system or CAIP system.

Further, shape facility of the present invention self-definedly comprises structural feature face attribute vector with the feature templates of recognition system, forms face topological and geometric relationship matrix, characteristic cross-section attribute constraint and feature geometries restriction on the parameters; Wherein,

Structural feature face attribute vector, for being divided into different set by structural feature face according to attribute and the status in structural feature, i.e. features component; And specify quantity and the attribute in the structural feature face in each features component; The form of structural feature face attribute vector is as shown in the formula (1):

[fa ₁,fa ₂,fa ₃,L,fa _n] (1)

In formula (1), the quantity of n representation feature assembly, element fa _i(i=1,2 ..., n) describe quantity and the attribute in structural feature face in i-th features component, its form is as shown in the formula (2):

fa _i＝<NUM,TYPE,CONC,CONS> (2)

In formula (2), NUM is the quantity in structural feature face in features component, is the quantification in structural feature face in features component when getting nonnegative integer, is the quantity in not structural feature face in limited features assembly when getting negative; TYPE is the type in structural feature face in features component, comprising: plane, the face of cylinder, circular conical surface, sphere, anchor ring, Extrude Face, the surfaces of revolution, fillet surface, hollows, offset plane, free form surface and type are not limit; CONC is the concavity and convexity in structural feature face in features component, comprising: plane, concave surface and convex surface; CONS is other constraint that in features component, structural feature face must meet, and comprising: surface level, dip plane, vertical plane and do not limit type;

Form face topological and geometric relationship matrix, for specifying between each features component, or the topology that must meet between each structural feature face in features component and geometric relationship retrain, and its form is as shown in the formula (3):

$\left[\begin{array}{ccccc}{\mathrm{tgr}}_{\mathrm{1,1}}& & & & \\ {\mathrm{tgr}}_{\mathrm{2,1}}& {\mathrm{tgr}}_{\mathrm{2,2}}& & & \\ {\mathrm{tgr}}_{\mathrm{3,1}}& {\mathrm{tgr}}_{\mathrm{3,2}}& {\mathrm{tgr}}_{\mathrm{3,3}}& & \\ & M& & O& \\ {\mathrm{tgr}}_{n,1}& {\mathrm{tgr}}_{n,2}& {\mathrm{tgr}}_{n,3}& L& {\mathrm{tgr}}_{n,n}\end{array}\right]---\left(3\right)$

In formula (3), the element tgr on off-diagonal _i,j(i>j, i, j=1,2 ..., n) for specifying between different assembly the topology that must meet and geometrical-restriction relation, any one the structural feature face namely in i-th assembly must meet tgr with some in a jth assembly _i,jthe restriction relation of regulation; Element tgr on diagonal line _i,i(i=1,2 ..., n) for specifying in same features component the topology that must meet between different characteristic formation face and geometrical-restriction relation, any one the structural feature face namely in i-th assembly must meet tgr with some in this assembly _i,ithe restriction relation of regulation; Described topological constraints relation comprises: the concavity and convexity constraint of adjacent constraint, adjacent edge and the attribute constraint of adjacent edge place ring, i.e. inner ring or outer shroud; Described geometrical-restriction relation comprises: tangent, parallel, vertical, tilt, coplanar, coaxial and staggered;

Characteristic cross-section attribute constraint, for specifying the constraint that the attribute of characteristic cross-section must meet, the feature that structural feature face attribute vector is all identical with geometric relationship matrix with being formed face topological with Distinguish difference, its form is following formula (4):

<FEA_AXIS,AXIS_PLANE,COM,CVPT_CONS,CXPT_CONS>(4)

In formula (4), FEA_AXIS representation feature coordinate system; The coordinate plane of AXIS_PLANE representation feature coordinate system, value is X_Y, X_Z or Y_Z plane; COM represents COM features component; CVPT_CONS specifies the constraint that characteristic cross-section fovea superior point quantity must meet; CXPT_CONS represents the constraint that regulation characteristic cross-section epirelief point quantity must meet;

Described characteristic coordinates is right-handed coordinate system, is defined by two features component, and its form is following formula (5):

FEA_AXIS＝<Z_DEFCOM,X_DEFCOM> (5)

The outer method that the Z axis of formula (5) representation feature coordinate system FEA_AXIS and X-axis positive dirction get Z_DEFCOM assembly and X_DEFCOM assembly midplane is respectively vowed, the axis of the surfaces of revolution or the draw direction of Extrude Face, or the outer method in any one face is vowed; Its priority is followed successively by earth by height: the outer method of plane is vowed, the axis of the surfaces of revolution or the draw direction of Extrude Face, arbitrary face outer method vow;

The form of described CVPT_CONS and CXPT_CONS is as shown in the formula (6):

<RELA,VAL> (6)

In formula (6), RELA is relation character, comprising: >, >=,==, <=and <; VAL represents the threshold value of salient point number or concave point number, is a round values;

The implication of characteristic cross-section attribute constraint is, defines a property coordinate system FEA_AXIS by Z_DEFCOM features component and X_DEFCOM features component; Friendship is asked with the AXIS_PLANE coordinate plane in property coordinate system FEA_AXIS and all structural feature faces in COM features component; If there is intersection in AXIS_PLANE coordinate plane and certain structural feature face, friendship is asked on all limits then on AXIS_PLANE coordinate plane and this structural feature face, and the concave, convex point quantity in gained intersection point must meet the constraint that CVPT_CONS and CXPT_CONS specifies respectively; Wherein, the concavity and convexity of intersection point is consistent with the concavity and convexity on its limit, place;

Feature geometries restriction on the parameters, for specifying the constraint that the geometric parameter of feature must meet, with Distinguish different and structural feature face attribute vector, formed the face topological feature all identical with characteristic cross-section attribute constraint with geometric relationship matrix, its form is as shown in the formula (7):

<PARA1,PARA2,RELA,PARAVAL> (7)

In formula (7), PARA1 and PARA2 is feature geometries parameter; RELA is relation character, comprising: >, >=,==, <=and <; The threshold value of PARAVAL representation feature geometric parameter is a real number value;

The implication of feature geometries restriction on the parameters is: if define PARA1 and PARA2 two feature geometries parameters simultaneously, then the magnitude relationship between the ratio of PARA1 and PARA2 and PARAVAL must meet the magnitude relationship that RELA specifies; If specify only any one parameter in PARA1 and PARA2, then the magnitude relationship between this feature geometries parameter and PARAVAL must meet the magnitude relationship that RELA specifies;

The form of feature geometries parameter PARA1 and PARA2 is as shown in the formula (8):

<COM1,COM2,PARA_NAME> (8)

In formula (8), COM1 and COM2 is the sequence number of features component; PARA_NAME is the feature geometries parameter name relevant with COM1 and COM2 features component; If define COM1 and COM2 two features component simultaneously, then PARA_NAME is that geometric parameters between two faces is several, comprise distance, angle and interlaces lengths, and for any structural feature face in assembly COM2, a structural feature face is all there is, the constraint making the geometric parameter specified by PARA_NAME between two faces meet formula (7) to specify in assembly COM1; If specify only any one assembly in COM1 and COM2 two features component, then PARA_NAME is that the geometric parameters in individual face is several, and must meet for the geometric parameter that any one structural feature face in this assembly is specified by PARA_NAME the constraint that formula (7) specifies; The geometric parameters in described formation face is several, comprising: plane length, plane width, face of cylinder radius, face of cylinder length, cylinder length, circular conical surface cone angle, spherical radius, anchor ring cross section radius of circle, anchor ring radius of turn, Extrude Face tensile elongation, the surfaces of revolution anglec of rotation, surfaces of revolution radius of turn, fillet surface chamfering width, fillet surface chamfer angle and hollows radius.

Further, shape facility of the present invention is self-defined with recognition system characteristic cross-section attribute constraint, and friendship is asked on all limits on AXIS_PLANE coordinate plane and this structural feature face, and the calculation procedure of its concave, convex point quantity is:

S101: structural feature face and AXIS_PLANE coordinate plane ask friendship to obtain an intersection L;

S102: all limits on structural feature face and AXIS_PLANE coordinate plane ask friendship to obtain a series of intersection point;

S103: intersection point is according to the name placement on intersection L;

S104: delete all salient points except initial and end point;

S105: the common edge between deletion structural feature face and the intersection point of AXIS_PLANE coordinate plane;

S106: the concave, convex point quantity in residue intersection point is the concave, convex point quantity of needs;

Wherein, FEA_AXIS is the property coordinate system by Z_DEFCOM features component and X_DEFCOM features component definition; The coordinate plane of AXIS_PLANE representation feature coordinate system, value is X_Y, X_Z or Y_Z plane.

Further, shape facility of the present invention self-defined with recognition system in the interactive interface of Features Management device, newly-built feature templates, comprises the following steps:

S201: input feature vector template name, is the characteristic type name of self-defining;

S202: create a features component, and specify the quantity in structural feature face in this assembly, type, concavity and convexity and other attribute;

S203: repeat step 202, until created all features component;

S204: regulation forms the value of each element in face topological and geometric relationship matrix, that is: specify between corresponding different characteristic assembly, or the topological sum geometric relationship constraint that must meet between different characteristic formation face in same assembly;

S205: create characteristic cross-section attribute constraint, and perform following operation: the features component of (1) specific characteristic coordinate system; (2) specific characteristic coordinate system coordinate plane; (3) features component need asking the place, structural feature face of friendship with property coordinate system coordinate plane is specified; (4) concave point number constraint is specified; (5) salient point number constraint is specified;

S206: repeat step 205, until created characteristic cross-section attribute constraint in need;

S207: create feature geometries restriction on the parameters, and perform following operation: (1) regulation features component COM1 relevant with feature geometries parameter PARA1 and COM2, and parameter name PARA_NAME; (2) the features component COM1 relevant with feature geometries parameter PARA2 and COM2 is specified, and parameter name PARA_NAME; (3) prescribed relationship symbol RELA; (4) specified value PARAVAL;

S208: repeat step 207, until created feature geometries restriction on the parameters in need;

S209: feature templates has been set up, feature templates is stored in feature database.

Further, shape facility of the present invention is self-defined revises feature templates with recognition system, comprising: (1) increases, subtracts features component; (2) quantity in structural feature face in features component, type, concavity and convexity and other attribute is changed; (3) change forms the value of each element in face topological and geometric relationship matrix; (4) increase, subtract characteristic cross-section attribute constraint; (5) certain characteristic cross-section attribute constraint is changed; (6) increase, subtract feature geometries restriction on the parameters; (7) certain feature geometries restriction on the parameters is changed.

Further, shape facility of the present invention is self-defined with recognition system query characteristics template, comprising: the quantity in structural feature face, type, concavity and convexity and other attribute in the features component that (1) query characteristics comprises and each assembly; (2) value of each element in the formation face topological of query characteristics and geometric relationship matrix; (3) the characteristic cross-section attribute constraint of query characteristics; (4) the feature geometries restriction on the parameters of query characteristics.

Further, the self-defined shape facility expression-form identified with recognition system feature identifier of shape facility of the present invention is as shown in the formula (9):

FEA＝<FEA_TYPE；COM ₁；COM ₂；……；COM _n> (9)

In formula (9), FEA_TYPE is characteristic type, COM _i(i=1,2 ..., n) be i-th features component be made up of some structural feature faces.

Further, shape facility of the present invention is self-defined with recognition system feature identifier identification any type shape facility, comprises the following steps:

S301: read in the feature templates intending the characteristic type identified from feature database;

S302: construct the 1st features component COM ₁, concrete steps comprise:

S3021: take out the 1st element fa in the attribute vector of structural feature face ₁=<NUM, TYPE, CONC, CONS>, find out type, concavity and convexity and other attribute and meet TYPE respectively, all piece surfaces of CONC and CONS regulation, and composition set FACES ₁; Wherein, NUM is the quantity in structural feature face in features component, is the quantification in structural feature face in features component when getting nonnegative integer, is the quantity in not structural feature face in limited features assembly when getting negative; TYPE is the type in structural feature face in features component, comprising: plane, the face of cylinder, circular conical surface, sphere, anchor ring, Extrude Face, the surfaces of revolution, fillet surface, hollows, offset plane, free form surface and type are not limit; CONC is the concavity and convexity in structural feature face in features component, comprising: plane, concave surface and convex surface; CONS is other constraint that in features component, structural feature face must meet, and comprising: surface level, dip plane, vertical plane and do not limit type;

S3022: take out only relevant with the 1st features component feature geometries restriction on the parameters, checks set FACES ₁in piece surface whether meet feature geometries restriction on the parameters, and from FACES ₁middle deletion does not meet the piece surface of constraint;

S3023: take out the element tgr formed in face topological and geometric relationship matrix _1,1, will FACES be gathered ₁be divided into some subsets: COM _1,1, COM _1,2..., COM _{1, m}, in each subset, the quantity of piece surface must meet the 1st element fa in the attribute vector of structural feature face ₁the regulation of middle NUM, and any one piece surface in each subset must meet tgr with some in this subset _1,1topology and the geometric relationship of regulation retrain;

S3024: the 1 features component COM ₁structure result be expressed as set RES ₁, i.e. formula (10):

${\mathrm{RES}}_1={\left\{\mathrm{FE}{A}_{1,j}\right\}}_{j=1}^m=\{<\mathrm{FEA}\_\mathrm{TYPE};{\mathrm{COM}}_{1,j}>{\}}_{j=1}^m---\left(10\right)$

S303: make i=2;

S304: if i>n, then go to step S306, wherein, n is the features component quantity of the type feature; Otherwise, make i-th features component COM _istructure result then, i-th features component COM is constructed _i, concrete steps are:

S3041: take out i-th element: fa in the attribute vector of structural feature face _i=<NUM, TYPE, CONC, CONS>, find out type, concavity and convexity and other attribute and meet TYPE respectively, all piece surfaces of CONC and CONS regulation, and composition set FACES _i;

S3042: make j=1;

S3043: if j>m, then go to step S305, wherein, m is i – 1 features component COM _i-1structure result RES _i-1in element number; Otherwise, take out RES _i-1in element FEA _{i-1, j};

S3044: take out the element tgr formed in face topological and geometric relationship matrix _{i, 1}~ tgr _{i, i-1}, check set FACES _iin each piece surface and FEA _{i-1, j}features component COM _k,j(k=1,2 ..., i – 1) in face between topological sum geometric relationship whether meet tgr _i,k(k=1,2 ..., i – 1) and the constraint that specifies, and the piece surface of all satisfied constraints is formed new set FACES _i';

S3045: take out only relevant with 1st ~ i features component feature geometries restriction on the parameters, checks set FACES _i' in piece surface whether meet feature geometries restriction on the parameters, and from FACES _i' the middle piece surface deleting satisfied constraint;

S3046: take out the element tgr formed in face topological and geometric relationship matrix _i,i, will FACES be gathered _i' be divided into some subsets: COM _{i, 1}, COM _{i, 2}..., COM _i,p, in each subset, the quantity of piece surface meets i-th element fa in the attribute vector of structural feature face _ithe regulation of middle NUM, and any one piece surface in each subset must meet tgr with some in this subset _i,itopology and the geometric relationship of regulation retrain;

S3047: the i-th features component COM _istructure result be expressed as set RES _i, i.e. formula (11):

$\begin{array}{c}{\mathrm{RES}}_i={\mathrm{RES}}_{i}U{\left\{{\mathrm{FEA}}_{i,j}\right\}}_{j=1}^p\\ ={\mathrm{RES}}_{i}U{\{<\mathrm{FEA}\_\mathrm{TYPE};{\mathrm{COM}}_{1,j};...;{\mathrm{COM}}_{i,j}>\}}_{j=1}^p\\ =\{<\mathrm{FEA}\_\mathrm{TYPE};{\mathrm{com}}_{1,j};...;{\mathrm{COM}}_{i,j}>{\}}_{j=1}^m\end{array}---\left(11\right)$

S3048: make j=j+1, goes to step S3043;

S305: make i=i+1, goes to step S304;

S306: examination characteristic cross-section attribute constraint: examination features component structure result RES _nin each element whether meet all characteristic cross-section attribute constraint, meet the element <FEA_TYPE of constraint; COM ₁; COM ₂; COM _n> is feature recognition result, that is: a features component COM ₁, COM ₂..., COM _nin to constitute a type be the shape facility of FEA_TYPE in all structural feature faces;

307: output characteristic recognition result.

Further, shape facility of the present invention is self-defined examines <FEA_TYPE with recognition system feature identifier; COM ₁; COM ₂; COM _nthe step whether > meets certain characteristic cross-section attribute constraint comprises:

S3061: calculate COM ₁, COM ₂..., COM _nin the mean place of all structural feature faces center of area, it can be used as the initial point of property coordinate system;

S3062: the Z axis positive dirction determining property coordinate system: the features component of taking out the definition Z axis that characteristic cross-section attribute constraint specifies, if having plane in this assembly, then the outer method calculating this plane is vowed, and it can be used as Z axis positive dirction; If without plane in this assembly, then calculate the draw direction of Extrude Face or the turning axle direction of the surfaces of revolution, and it can be used as Z axis positive dirction; If both without plane in this assembly, also tensionless winkler foundation face and the surfaces of revolution, then the outer method in any face in this assembly that calculates is vowed, and it can be used as Z axis positive dirction;

S3063: the X-axis positive dirction determining property coordinate system: the features component of taking out the definition X-axis that characteristic cross-section attribute constraint specifies, if having plane in this assembly, then the outer method calculating this plane is vowed, and it can be used as X-axis positive dirction; If without plane in this assembly, then calculate the draw direction of Extrude Face or the turning axle direction of the surfaces of revolution, and it can be used as X-axis positive dirction; If both without plane in this assembly, also tensionless winkler foundation face and the surfaces of revolution, then the outer method in any face in this assembly that calculates is vowed, and it can be used as X-axis positive dirction;

S3064: the Y-axis positive dirction determining property coordinate system: according to Z axis positive dirction and X-axis positive dirction, according to right-handed coordinate system determination Y-axis positive dirction;

S3065: the coordinate plane AXIS_PLANE taking out the property coordinate system that characteristic cross-section attribute constraint specifies;

S3066: make i=1;

S3067: if the structural feature face quantity in the features component COM that specifies of characteristic cross-section attribute constraint is more than or equal to i, then takes out i-th structural feature face FACE in this assembly, turn S3068; Otherwise, character symbol contract bundle, the examination of this characteristic cross-section attribute constraint terminates;

S3068: structural feature face FACE and AXIS_PLANE coordinate plane ask friendship, if there is intersection L, then go to step S3069, otherwise go to step S30614;

S3069: all limits on the FACE of structural feature face and AXIS_PLANE coordinate plane ask friendship to obtain a series of intersection point, and judge the concavity and convexity of each intersection point;

S30610: intersection point is according to the name placement on intersection L;

S30611: delete all salient points except initial and end point;

S30612: the common edge between deletion structural feature face and the intersection point of AXIS_PLANE coordinate plane;

S30613: if the concave, convex point quantity in residue intersection point is discontented with the concave, convex point number constraint that sufficient characteristic cross-section attribute constraint specifies, then this feature does not meet constraint, and examination terminates, otherwise goes to step S30614;

S30614: make i=i+1, goes to step S3067.

Shape facility of the present invention is self-defined is can under the condition CAPP or CAIP system not being made to any change with the Advantageous Effects of recognition system, the feature identification range of expanding system easily, enhance dirigibility and the applicability of feature identification, significantly expand the scope of the shape facility type of CAPP or CAIP system identification, make to increase new shape facility comparatively easy.

Accompanying drawing explanation

Accompanying drawing 1 is the self-defined structural representation with recognition system of shape facility of the present invention;

Accompanying drawing 2 is the self-defined step schematic diagram increasing new shape facility with recognition system of shape facility of the present invention;

Accompanying drawing 3 is the self-defined step schematic diagram with recognition system identification shape facility of shape facility of the present invention;

Accompanying drawing 4 is the self-defined step schematic diagram examined with recognition system characteristic cross-section attribute constraint of shape facility of the present invention.

Be further described with recognition system shape facility of the present invention is self-defined below in conjunction with the drawings and specific embodiments.

Embodiment

Accompanying drawing 1 is the self-defined structural representation with recognition system of shape facility of the present invention, as seen from the figure, shape facility of the present invention is self-defined comprises feature database, Features Management device and feature identifier with recognition system, and embed in mechanical component CAPP CAPP or computer aided detection planning CAIP, wherein

Feature database is for storing the feature templates of various shape type, and described feature templates is used for carrying out standardization to shape facility and describes, and all types of feature templates has unified expression and file layout in feature database;

Features Management device is used for the feature templates in characteristics of management storehouse, comprises newly-built feature templates, amendment feature templates, query characteristics template and deletion feature templates;

Feature identifier is used for shape facility identification, and provides feature recognition result to CAPP system or CAIP system.

For expression and the storage enforcement of all feature templates in specification and uniform characteristics storehouse, so that the shape facility in the new shape facility of system creation and recognition feature storehouse, shape facility of the present invention is self-defined comprises structural feature face attribute vector with the feature templates of recognition system, form face topological and geometric relationship matrix, characteristic cross-section attribute constraint and feature geometries restriction on the parameters; Wherein,

Structural feature face attribute vector, for being divided into different set by structural feature face according to attribute and the status in structural feature, i.e. features component; And specify quantity and the attribute in the structural feature face in each features component; The form of structural feature face attribute vector is as shown in the formula (1):

[fa ₁,fa ₂,fa ₃,L,fa _n] (1)

In formula (1), the quantity of n representation feature assembly, element fa _i(i=1,2 ..., n) describe quantity and the attribute in structural feature face in i-th features component, its form is as shown in the formula (2):

fa _i＝<NUM,TYPE,CONC,CONS> (2)

In formula (2), NUM is the quantity in structural feature face in features component, is the quantification in structural feature face in features component when getting nonnegative integer, is the quantity in not structural feature face in limited features assembly when getting negative; TYPE is the type in structural feature face in features component, comprising: plane, the face of cylinder, circular conical surface, sphere, anchor ring, Extrude Face, the surfaces of revolution, fillet surface, hollows, offset plane, free form surface and type are not limit; CONC is the concavity and convexity in structural feature face in features component, comprising: plane, concave surface and convex surface; CONS is other constraint that in features component, structural feature face must meet, and comprising: surface level, dip plane, vertical plane and do not limit type;

Form face topological and geometric relationship matrix, for specifying between each features component, or the topology that must meet between each structural feature face in features component and geometric relationship retrain, and its form is as shown in the formula (3):

$\left[\begin{array}{ccccc}{\mathrm{tgr}}_{\mathrm{1,1}}& & & & \\ {\mathrm{tgr}}_{\mathrm{2,1}}& {\mathrm{tgr}}_{\mathrm{2,2}}& & & \\ {\mathrm{tgr}}_{\mathrm{3,1}}& {\mathrm{tgr}}_{\mathrm{3,2}}& {\mathrm{tgr}}_{\mathrm{3,3}}& & \\ & M& & O& \\ {\mathrm{tgr}}_{n,1}& {\mathrm{tgr}}_{n,2}& {\mathrm{tgr}}_{n,3}& L& {\mathrm{tgr}}_{n,n}\end{array}\right]---\left(3\right)$

In formula (3), the element tgr on off-diagonal _i,j(i>j, i, j=1,2 ..., n) for specifying between different assembly the topology that must meet and geometrical-restriction relation, any one the structural feature face namely in i-th assembly must meet tgr with some in a jth assembly _i,jthe restriction relation of regulation; Element tgr on diagonal line _i,i(i=1,2 ..., n) for specifying in same features component the topology that must meet between different characteristic formation face and geometrical-restriction relation, any one the structural feature face namely in i-th assembly must meet tgr with some in this assembly _i,ithe restriction relation of regulation; Described topological constraints relation comprises: the concavity and convexity constraint of adjacent constraint, adjacent edge and the attribute constraint of adjacent edge place ring, i.e. inner ring or outer shroud; Described geometrical-restriction relation comprises: tangent, parallel, vertical, tilt, coplanar, coaxial and staggered;

Characteristic cross-section attribute constraint, for specifying the constraint that the attribute of characteristic cross-section must meet, the feature that structural feature face attribute vector is all identical with geometric relationship matrix with being formed face topological with Distinguish difference, its form is following formula (4):

<FEA_AXIS,AXIS_PLANE,COM,CVPT_CONS,CXPT_CONS>(4)

In formula (4), FEA_AXIS representation feature coordinate system; The coordinate plane of AXIS_PLANE representation feature coordinate system, value is X_Y, X_Z or Y_Z plane; COM represents COM features component; CVPT_CONS specifies the constraint that characteristic cross-section fovea superior point quantity must meet; CXPT_CONS represents the constraint that regulation characteristic cross-section epirelief point quantity must meet;

Described characteristic coordinates is right-handed coordinate system, is defined by two features component, and its form is following formula (5):

FEA_AXIS＝<Z_DEFCOM,X_DEFCOM> (5)

The outer method that the Z axis of formula (5) representation feature coordinate system FEA_AXIS and X-axis positive dirction get Z_DEFCOM assembly and X_DEFCOM assembly midplane is respectively vowed, the axis of the surfaces of revolution or the draw direction of Extrude Face, or the outer method in any one face is vowed; Its priority is followed successively by earth by height: the outer method of plane is vowed, the axis of the surfaces of revolution or the draw direction of Extrude Face, arbitrary face outer method vow;

The form of described CVPT_CONS and CXPT_CONS is as shown in the formula (6):

<RELA,VAL> (6)

In formula (6), RELA is relation character, comprising: >, >=,==, <=and <; VAL represents the threshold value of salient point number or concave point number, is a round values;

The implication of characteristic cross-section attribute constraint is, defines a property coordinate system FEA_AXIS by Z_DEFCOM features component and X_DEFCOM features component; Friendship is asked with the AXIS_PLANE coordinate plane in property coordinate system FEA_AXIS and all structural feature faces in COM features component; If there is intersection in AXIS_PLANE coordinate plane and certain structural feature face, friendship is asked on all limits then on AXIS_PLANE coordinate plane and this structural feature face, and the concave, convex point quantity in gained intersection point must meet the constraint that CVPT_CONS and CXPT_CONS specifies respectively; Wherein, the concavity and convexity of intersection point is consistent with the concavity and convexity on its limit, place;

Feature geometries restriction on the parameters, for specifying the constraint that the geometric parameter of feature must meet, with Distinguish different and structural feature face attribute vector, formed the face topological feature all identical with characteristic cross-section attribute constraint with geometric relationship matrix, its form is as shown in the formula (7):

<PARA1,PARA2,RELA,PARAVAL> (7)

In formula (7), PARA1 and PARA2 is feature geometries parameter; RELA is relation character, comprising: >, >=,==, <=and <; The threshold value of PARAVAL representation feature geometric parameter is a real number value;

The implication of feature geometries restriction on the parameters is: if define PARA1 and PARA2 two feature geometries parameters simultaneously, then the magnitude relationship between the ratio of PARA1 and PARA2 and PARAVAL must meet the magnitude relationship that RELA specifies; If specify only any one parameter in PARA1 and PARA2, then the magnitude relationship between this feature geometries parameter and PARAVAL must meet the magnitude relationship that RELA specifies;

The form of feature geometries parameter PARA1 and PARA2 is as shown in the formula (8):

<COM1,COM2,PARA_NAME> (8)

In formula (8), COM1 and COM2 is the sequence number of features component; PARA_NAME is the feature geometries parameter name relevant with COM1 and COM2 features component; If define COM1 and COM2 two features component simultaneously, then PARA_NAME is that geometric parameters between two faces is several, comprise distance, angle and interlaces lengths, and for any structural feature face in assembly COM2, a structural feature face is all there is, the constraint making the geometric parameter specified by PARA_NAME between two faces meet formula (7) to specify in assembly COM1; If specify only any one assembly in COM1 and COM2 two features component, then PARA_NAME is that the geometric parameters in individual face is several, and must meet for the geometric parameter that any one structural feature face in this assembly is specified by PARA_NAME the constraint that formula (7) specifies; The geometric parameters in described formation face is several, comprising: plane length, plane width, face of cylinder radius, face of cylinder length, cylinder length, circular conical surface cone angle, spherical radius, anchor ring cross section radius of circle, anchor ring radius of turn, Extrude Face tensile elongation, the surfaces of revolution anglec of rotation, surfaces of revolution radius of turn, fillet surface chamfering width, fillet surface chamfer angle and hollows radius.

Shape facility of the present invention is self-defined with recognition system characteristic cross-section attribute constraint, and friendship is asked on all limits on AXIS_PLANE coordinate plane and this structural feature face, and the calculation procedure of its concave, convex point quantity is:

S101: structural feature face and AXIS_PLANE coordinate plane ask friendship to obtain an intersection L;

S102: all limits on structural feature face and AXIS_PLANE coordinate plane ask friendship to obtain a series of intersection point;

S103: intersection point is according to the name placement on intersection L;

S104: delete all salient points except initial and end point;

S105: the common edge between deletion structural feature face and the intersection point of AXIS_PLANE coordinate plane;

S106: the concave, convex point quantity in residue intersection point is the concave, convex point quantity of needs;

Wherein, FEA_AXIS is the property coordinate system by Z_DEFCOM features component and X_DEFCOM features component definition; The coordinate plane of AXIS_PLANE representation feature coordinate system, value is X_Y, X_Z or Y_Z plane.

Accompanying drawing 2 is the self-defined step schematic diagram increasing new shape facility with recognition system of shape facility of the present invention, and as seen from the figure, shape facility of the present invention is self-defined with recognition system newly-built feature templates in the interactive interface of Features Management device, comprises the following steps:

S201: input feature vector template name, is the characteristic type name of self-defining;

S202: create a features component, and specify the quantity in structural feature face in this assembly, type, concavity and convexity and other attribute;

S203: repeat step 202, until created all features component;

S204: regulation forms the value of each element in face topological and geometric relationship matrix, that is: specify between corresponding different characteristic assembly, or the topological sum geometric relationship constraint that must meet between different characteristic formation face in same assembly;

S205: create characteristic cross-section attribute constraint, and perform following operation: the features component of (1) specific characteristic coordinate system; (2) specific characteristic coordinate system coordinate plane; (3) features component need asking the place, structural feature face of friendship with property coordinate system coordinate plane is specified; (4) concave point number constraint is specified; (5) salient point number constraint is specified;

S206: repeat step 205, until created characteristic cross-section attribute constraint in need;

S207: create feature geometries restriction on the parameters, and perform following operation: (1) regulation features component COM1 relevant with feature geometries parameter PARA1 and COM2, and parameter name PARA_NAME; (2) the features component COM1 relevant with feature geometries parameter PARA2 and COM2 is specified, and parameter name PARA_NAME; (3) prescribed relationship symbol RELA; (4) specified value PARAVAL;

S208: repeat step 207, until created feature geometries restriction on the parameters in need;

S209: feature templates has been set up, feature templates is stored in feature database.

Shape facility of the present invention is self-defined revises feature templates with recognition system, comprising: (1) increases, subtracts features component; (2) quantity in structural feature face in features component, type, concavity and convexity and other attribute is changed; (3) change forms the value of each element in face topological and geometric relationship matrix; (4) increase, subtract characteristic cross-section attribute constraint; (5) certain characteristic cross-section attribute constraint is changed; (6) increase, subtract feature geometries restriction on the parameters; (7) certain feature geometries restriction on the parameters is changed.

Shape facility of the present invention is self-defined with recognition system query characteristics template, comprising: the quantity in structural feature face, type, concavity and convexity and other attribute in the features component that (1) query characteristics comprises and each assembly; (2) value of each element in the formation face topological of query characteristics and geometric relationship matrix; (3) the characteristic cross-section attribute constraint of query characteristics; (4) the feature geometries restriction on the parameters of query characteristics.

The self-defined shape facility expression-form identified with recognition system feature identifier of shape facility of the present invention is as shown in the formula (9):

FEA＝<FEA_TYPE；COM ₁；COM ₂；……；COM _n> (9)

In formula (9), FEA_TYPE is characteristic type, COM _i(i=1,2 ..., n) be i-th features component be made up of some structural feature faces.

Accompanying drawing 3 is the self-defined step schematic diagram with recognition system identification shape facility of shape facility of the present invention, and as seen from the figure, shape facility of the present invention is self-defined with recognition system feature identifier identification any type shape facility, comprises the following steps:

S301: read in the feature templates intending the characteristic type identified from feature database;

S302: construct the 1st features component COM ₁, concrete steps comprise:

S3021: take out the 1st element fa in the attribute vector of structural feature face ₁=<NUM, TYPE, CONC, CONS>, find out type, concavity and convexity and other attribute and meet TYPE respectively, all piece surfaces of CONC and CONS regulation, and composition set FACES ₁; Wherein, NUM is the quantity in structural feature face in features component, is the quantification in structural feature face in features component when getting nonnegative integer, is the quantity in not structural feature face in limited features assembly when getting negative; TYPE is the type in structural feature face in features component, comprising: plane, the face of cylinder, circular conical surface, sphere, anchor ring, Extrude Face, the surfaces of revolution, fillet surface, hollows, offset plane, free form surface and type are not limit; CONC is the concavity and convexity in structural feature face in features component, comprising: plane, concave surface and convex surface; CONS is other constraint that in features component, structural feature face must meet, and comprising: surface level, dip plane, vertical plane and do not limit type;

S3022: take out only relevant with the 1st features component feature geometries restriction on the parameters, checks set FACES ₁in piece surface whether meet feature geometries restriction on the parameters, and from FACES ₁middle deletion does not meet the piece surface of constraint;

S3023: take out the element tgr formed in face topological and geometric relationship matrix _1,1, will FACES be gathered ₁be divided into some subsets: COM _1,1, COM _1,2..., COM _{1, m}, in each subset, the quantity of piece surface must meet the 1st element fa in the attribute vector of structural feature face ₁the regulation of middle NUM, and any one piece surface in each subset must meet tgr with some in this subset _1,1topology and the geometric relationship of regulation retrain;

S3024: the 1 features component COM ₁structure result be expressed as set RES ₁, i.e. formula (10):

${\mathrm{RES}}_1={\left\{\mathrm{FE}{A}_{1,j}\right\}}_{j=1}^m=\{<\mathrm{FEA}\_\mathrm{TYPE};{\mathrm{COM}}_{1,j}>{\}}_{j=1}^m---\left(10\right)$

S303: make i=2;

S304: if i>n, then go to step S306, wherein, n is the features component quantity of the type feature; Otherwise, make i-th features component COM _istructure result then, i-th features component COM is constructed _i, concrete steps are:

S3041: take out i-th element fa in the attribute vector of structural feature face _i=<NUM, TYPE, CONC, CONS>, find out type, concavity and convexity and other attribute and meet TYPE respectively, all piece surfaces of CONC and CONS regulation, and composition set FACES _i;

S3042: make j=1;

S3043: if j>m, then go to step S305, wherein, m is i – 1 features component COM _i-1structure result RES _i-1in element number; Otherwise, take out RES _i-1in element FEA _{i-1, j};

S3044: take out the element tgr formed in face topological and geometric relationship matrix _{i, 1}~ tgr _{i, i-1}, check set FACES _iin each piece surface and FEA _{i-1, j}features component COM _k,j(k=1,2 ..., i – 1) in face between topological sum geometric relationship whether meet tgr _i,k(k=1,2 ..., i – 1) and the constraint that specifies, and the piece surface of all satisfied constraints is formed new set FACES _i';

S3045: take out only relevant with 1st ~ i features component feature geometries restriction on the parameters, checks set FACES _i' in piece surface whether meet feature geometries restriction on the parameters, and from FACES _i' the middle piece surface deleting satisfied constraint;

S3046: take out the element tgr formed in face topological and geometric relationship matrix _i,i, will FACES be gathered _i' be divided into some subsets: COM _{i, 1}, COM _{i, 2}..., COM _i,p, in each subset, the quantity of piece surface meets i-th element fa in the attribute vector of structural feature face _ithe regulation of middle NUM, and any one piece surface in each subset must meet tgr with some in this subset _i,itopology and the geometric relationship of regulation retrain;

S3047: the i-th features component COM _istructure result be expressed as set RES _i, i.e. formula (11):

$\begin{array}{c}{\mathrm{RES}}_i={\mathrm{RES}}_{i}U{\left\{{\mathrm{FEA}}_{i,j}\right\}}_{j=1}^p\\ ={\mathrm{RES}}_{i}U{\{<\mathrm{FEA}\_\mathrm{TYPE};{\mathrm{COM}}_{1,j};...;{\mathrm{COM}}_{i,j}>\}}_{j=1}^p\\ =\{<\mathrm{FEA}\_\mathrm{TYPE};{\mathrm{COM}}_{1,j};...;{\mathrm{COM}}_{i,j}>{\}}_{j=1}^m\end{array}---\left(11\right)$

S3048: make j=j+1, goes to step S3043;

S305: make i=i+1, goes to step S304;

S306: examination characteristic cross-section attribute constraint: examination features component structure result RES _nin each element whether meet all characteristic cross-section attribute constraint, meet the element <FEA_TYPE of constraint; COM ₁; COM ₂; COM _n> is feature recognition result, that is: a features component COM ₁, COM ₂..., COM _nin to constitute a type be the shape facility of FEA_TYPE in all structural feature faces;

307: output characteristic recognition result.

Accompanying drawing 4 is the self-defined step schematic diagram examined with recognition system characteristic cross-section attribute constraint of shape facility of the present invention, and as seen from the figure, shape facility of the present invention is self-defined examines <FEA_TYPE with recognition system feature identifier; COM ₁; COM ₂; COM _nwhether > meets the step of certain characteristic cross-section attribute constraint, comprising:

S3061: calculate COM ₁, COM ₂..., COM _nin the mean place of all structural feature faces center of area, it can be used as the initial point of property coordinate system;

S3062: the Z axis positive dirction determining property coordinate system: the features component of taking out the definition Z axis that characteristic cross-section attribute constraint specifies, if having plane in this assembly, then the outer method calculating this plane is vowed, and it can be used as Z axis positive dirction; If without plane in this assembly, then calculate the draw direction of Extrude Face or the turning axle direction of the surfaces of revolution, and it can be used as Z axis positive dirction; If both without plane in this assembly, also tensionless winkler foundation face and the surfaces of revolution, then the outer method in any face in this assembly that calculates is vowed, and it can be used as Z axis positive dirction;

S3063: the X-axis positive dirction determining property coordinate system: the features component of taking out the definition X-axis that characteristic cross-section attribute constraint specifies, if having plane in this assembly, then the outer method calculating this plane is vowed, and it can be used as X-axis positive dirction; If without plane in this assembly, then calculate the draw direction of Extrude Face or the turning axle direction of the surfaces of revolution, and it can be used as X-axis positive dirction; If both without plane in this assembly, also tensionless winkler foundation face and the surfaces of revolution, then the outer method in any face in this assembly that calculates is vowed, and it can be used as X-axis positive dirction;

S3064: the Y-axis positive dirction determining property coordinate system: according to Z axis positive dirction and X-axis positive dirction, according to right-handed coordinate system determination Y-axis positive dirction;

S3065: the coordinate plane AXIS_PLANE taking out the property coordinate system that characteristic cross-section attribute constraint specifies;

S3066: make i=1;

S3067: if the structural feature face quantity in the features component COM that specifies of characteristic cross-section attribute constraint is more than or equal to i, then takes out i-th structural feature face FACE in this assembly, go to step S3068; Otherwise, character symbol contract bundle, the examination of this characteristic cross-section attribute constraint terminates;

S3068: structural feature face FACE and AXIS_PLANE coordinate plane ask friendship, if there is intersection L, then go to step S3069, otherwise go to step S30614;

S3069: all limits on the FACE of structural feature face and AXIS_PLANE coordinate plane ask friendship to obtain a series of intersection point, and judge the concavity and convexity of each intersection point;

S30610: intersection point is according to the name placement on intersection L;

S30611: delete all salient points except initial and end point;

S30612: the common edge between deletion structural feature face and the intersection point of AXIS_PLANE coordinate plane;

S30613: if the concave, convex point quantity in residue intersection point is discontented with the concave, convex point number constraint that sufficient characteristic cross-section attribute constraint specifies, then this feature does not meet constraint, and examination terminates, otherwise goes to step S30614;

S30614: make i=i+1, goes to step S3067.

Obviously, shape facility of the present invention is self-defined is can under the condition CAPP or CAIP system not being made to any change with the Advantageous Effects of recognition system, the feature identification range of expanding system easily, enhance dirigibility and the applicability of feature identification, significantly expand the scope of the shape facility type of CAPP or CAIP system identification, make to increase new shape facility comparatively easy.

Claims (9)

1. the self-defined and recognition system of shape facility, is characterized in that: this system comprises feature database, Features Management device and feature identifier, and embeds in mechanical component CAPP CAPP or computer aided detection planning CAIP, wherein,

Feature database is for storing the feature templates of various shape type, and described feature templates is used for carrying out standardization to shape facility and describes, and all types of feature templates has unified expression and file layout in feature database;

Features Management device is used for the feature templates in characteristics of management storehouse, comprises newly-built feature templates, amendment feature templates, query characteristics template and deletion feature templates;

Feature identifier is used for shape facility identification, and provides feature recognition result to CAPP system or CAIP system.

2. the self-defined and recognition system of shape facility according to claim 1, is characterized in that: feature templates comprises structural feature face attribute vector, forms face topological and geometric relationship matrix, characteristic cross-section attribute constraint and feature geometries restriction on the parameters; Wherein,

Structural feature face attribute vector, for being divided into different set by structural feature face according to attribute and the status in structural feature, i.e. features component; And specify quantity and the attribute in the structural feature face in each features component; The form of structural feature face attribute vector is as shown in the formula (1):

[fa ₁,fa ₂,fa ₃,L,fa _n] (1)

In formula (1), the quantity of n representation feature assembly, element fa _i, i=1,2 ..., n, describe quantity and the attribute in structural feature face in i-th features component, its form is as shown in the formula (2):

fa _i＝<NUM,TYPE,CONC,CONS> (2)

In formula (2), NUM is the quantity in structural feature face in features component, is the quantification in structural feature face in features component when getting nonnegative integer, is the quantity in not structural feature face in limited features assembly when getting negative; TYPE is the type in structural feature face in features component, comprising: plane, the face of cylinder, circular conical surface, sphere, anchor ring, Extrude Face, the surfaces of revolution, fillet surface, hollows, offset plane, free form surface and type are not limit; CONC is the concavity and convexity in structural feature face in features component, comprising: plane, concave surface and convex surface; CONS is other constraint that in features component, structural feature face must meet, and comprising: surface level, dip plane, vertical plane and do not limit type;

Form face topological and geometric relationship matrix, for specifying between each features component, or the topology that must meet between each structural feature face in features component and geometric relationship retrain, and its form is as shown in the formula (3):

$\left[\begin{array}{ccccc}{\mathrm{tgr}}_{\mathrm{1,1}}& & & & \\ {\mathrm{tgr}}_{\mathrm{2,1}}& {\mathrm{tgr}}_{\mathrm{2,2}}& & & \\ {\mathrm{tgr}}_{\mathrm{3,1}}& {\mathrm{tgr}}_{\mathrm{3,2}}& {\mathrm{tgr}}_{\mathrm{3,3}}& & \\ & M& & O& \\ {\mathrm{tgr}}_{n,1}& {\mathrm{tgr}}_{n,2}& {\mathrm{tgr}}_{n,3}& L& {\mathrm{tgr}}_{n,n}\end{array}\right]---\left(3\right)$

In formula (3), the element tgr on off-diagonal _i,j, i>j, i, j=1,2 ..., n, for specifying between different assembly the topology that must meet and geometrical-restriction relation, any one the structural feature face namely in i-th assembly must meet tgr with some in a jth assembly _i,jthe restriction relation of regulation; Element tgr on diagonal line _i,i, i=1,2 ..., n, for specifying in same features component the topology that must meet between different characteristic formation face and geometrical-restriction relation, any one the structural feature face namely in i-th assembly must meet tgr with some in this assembly _i,ithe restriction relation of regulation; Described topological constraints relation comprises: the concavity and convexity constraint of adjacent constraint, adjacent edge and the attribute constraint of adjacent edge place ring, i.e. inner ring or outer shroud; Described geometrical-restriction relation comprises: tangent, parallel, vertical, tilt, coplanar, coaxial and staggered;

Characteristic cross-section attribute constraint, for specifying the constraint that the attribute of characteristic cross-section must meet, the feature that structural feature face attribute vector is all identical with geometric relationship matrix with being formed face topological with Distinguish difference, its form is following formula (4):

<FEA_AXIS,AXIS_PLANE,COM,CVPT_CONS,CXPT_CONS>(4)

In formula (4), FEA_AXIS representation feature coordinate system; The coordinate plane of AXIS_PLANE representation feature coordinate system, value is X_Y, X_Z or Y_Z plane; COM represents COM features component; CVPT_CONS specifies the constraint that characteristic cross-section fovea superior point quantity must meet; CXPT_CONS represents the constraint that regulation characteristic cross-section epirelief point quantity must meet;

Described characteristic coordinates is right-handed coordinate system, is defined by two features component, and its form is following formula (5):

FEA_AXIS＝<Z_DEFCOM,X_DEFCOM> (5)

The outer method that the Z axis of formula (5) representation feature coordinate system FEA_AXIS and X-axis positive dirction get Z_DEFCOM assembly and X_DEFCOM assembly midplane is respectively vowed, the axis of the surfaces of revolution or the draw direction of Extrude Face, or the outer method in any one face is vowed; Its priority is followed successively by earth by height: the outer method of plane is vowed, the axis of the surfaces of revolution or the draw direction of Extrude Face, arbitrary face outer method vow;

The form of described CVPT_CONS and CXPT_CONS is as shown in the formula (6):

<RELA,VAL> (6)

In formula (6), RELA is relation character, comprising: >, >=,==, <=and <; VAL represents the threshold value of salient point number or concave point number, is a round values;

The implication of characteristic cross-section attribute constraint is, defines a property coordinate system FEA_AXIS by Z_DEFCOM features component and X_DEFCOM features component; Friendship is asked with the AXIS_PLANE coordinate plane in property coordinate system FEA_AXIS and all structural feature faces in COM features component; If there is intersection in AXIS_PLANE coordinate plane and certain structural feature face, friendship is asked on all limits then on AXIS_PLANE coordinate plane and this structural feature face, and the concave, convex point quantity in gained intersection point must meet the constraint that CVPT_CONS and CXPT_CONS specifies respectively; Wherein, the concavity and convexity of intersection point is consistent with the concavity and convexity on its limit, place;

Feature geometries restriction on the parameters, for specifying the constraint that the geometric parameter of feature must meet, with Distinguish different and structural feature face attribute vector, formed the face topological feature all identical with characteristic cross-section attribute constraint with geometric relationship matrix, its form is as shown in the formula (7):

<PARA1,PARA2,RELA,PARAVAL> (7)

In formula (7), PARA1 and PARA2 is feature geometries parameter; RELA is relation character, comprising: >, >=,==, <=and <; The threshold value of PARAVAL representation feature geometric parameter is a real number value;

The implication of feature geometries restriction on the parameters is: if define PARA1 and PARA2 two feature geometries parameters simultaneously, then the magnitude relationship between the ratio of PARA1 and PARA2 and PARAVAL must meet the magnitude relationship that RELA specifies; If specify only any one parameter in PARA1 and PARA2, then the magnitude relationship between this feature geometries parameter and PARAVAL must meet the magnitude relationship that RELA specifies;

The form of feature geometries parameter PARA1 and PARA2 is as shown in the formula (8):

<COM1,COM2,PARA_NAME> (8)

In formula (8), COM1 and COM2 is the sequence number of features component; PARA_NAME is the feature geometries parameter name relevant with COM1 and COM2 features component; If define COM1 and COM2 two features component simultaneously, then PARA_NAME is that geometric parameters between two faces is several, comprise distance, angle and interlaces lengths, and for any structural feature face in assembly COM2, a structural feature face is all there is, the constraint making the geometric parameter specified by PARA_NAME between two faces meet formula (7) to specify in assembly COM1; If specify only any one assembly in COM1 and COM2 two features component, then PARA_NAME is that the geometric parameters in individual face is several, and must meet for the geometric parameter that any one structural feature face in this assembly is specified by PARA_NAME the constraint that formula (7) specifies; The geometric parameters in described formation face is several, comprising: plane length, plane width, face of cylinder radius, face of cylinder length, cylinder length, circular conical surface cone angle, spherical radius, anchor ring cross section radius of circle, anchor ring radius of turn, Extrude Face tensile elongation, the surfaces of revolution anglec of rotation, surfaces of revolution radius of turn, fillet surface chamfering width, fillet surface chamfer angle and hollows radius.

3. the self-defined and recognition system of shape facility according to claim 2, is characterized in that: in characteristic cross-section attribute constraint, and friendship is asked on all limits on AXIS_PLANE coordinate plane and this structural feature face, and the calculation procedure of its concave, convex point quantity is:

S101: structural feature face and AXIS_PLANE coordinate plane ask friendship to obtain an intersection L;

S102: all limits on structural feature face and AXIS_PLANE coordinate plane ask friendship to obtain a series of intersection point;

S103: intersection point is according to the name placement on intersection L;

S104: delete all salient points except initial and end point;

S105: the common edge between deletion structural feature face and the intersection point of AXIS_PLANE coordinate plane;

S106: the concave, convex point quantity in residue intersection point is the concave, convex point quantity of needs;

Wherein, FEA_AXIS is the property coordinate system by Z_DEFCOM features component and X_DEFCOM features component definition; The coordinate plane of AXIS_PLANE representation feature coordinate system, value is X_Y, X_Z or Y_Z plane.

4. the self-defined and recognition system of shape facility according to claim 1, it is characterized in that: in the interactive interface of Features Management device, newly-built feature templates, comprises the following steps:

S201: input feature vector template name, is the characteristic type name of self-defining;

S202: create a features component, and specify the quantity in structural feature face in this assembly, type, concavity and convexity and other attribute;

S203: repeat step 202, until created all features component;

S204: regulation forms the value of each element in face topological and geometric relationship matrix, that is: specify between corresponding different characteristic assembly, or the topological sum geometric relationship constraint that must meet between different characteristic formation face in same assembly;

S205: create characteristic cross-section attribute constraint, and perform following operation: the features component of (1) specific characteristic coordinate system; (2) specific characteristic coordinate system coordinate plane; (3) features component need asking the place, structural feature face of friendship with property coordinate system coordinate plane is specified; (4) concave point number constraint is specified; (5) salient point number constraint is specified;

S206: repeat step 205, until created characteristic cross-section attribute constraint in need;

S207: create feature geometries restriction on the parameters, and perform following operation: (1) regulation features component COM1 relevant with feature geometries parameter PARA1 and COM2, and parameter name PARA_NAME; (2) the features component COM1 relevant with feature geometries parameter PARA2 and COM2 is specified, and parameter name PARA_NAME; (3) prescribed relationship symbol RELA; (4) specified value PARAVAL;

S208: repeat step 207, until created feature geometries restriction on the parameters in need;

S209: feature templates has been set up, feature templates is stored in feature database.

5. the self-defined and recognition system of shape facility according to claim 1, is characterized in that: amendment feature templates, comprising: (1) increases, subtracts features component; (2) quantity in structural feature face in features component, type, concavity and convexity and other attribute is changed; (3) change forms the value of each element in face topological and geometric relationship matrix; (4) increase, subtract characteristic cross-section attribute constraint; (5) certain characteristic cross-section attribute constraint is changed; (6) increase, subtract feature geometries restriction on the parameters; (7) certain feature geometries restriction on the parameters is changed.

6. the self-defined and recognition system of shape facility according to claim 1, it is characterized in that: query characteristics template, comprising: the quantity in structural feature face, type, concavity and convexity and other attribute in the features component that (1) query characteristics comprises and each assembly; (2) value of each element in the formation face topological of query characteristics and geometric relationship matrix; (3) the characteristic cross-section attribute constraint of query characteristics; (4) the feature geometries restriction on the parameters of query characteristics.

7. the self-defined and recognition system of shape facility according to claim 1, is characterized in that: the shape facility expression-form that feature identifier identifies is as shown in the formula (9):

FEA＝<FEA_TYPE；COM ₁；COM ₂；……；COM _n> (9)

In formula (9), FEA_TYPE is characteristic type, COM _i, i=1,2 ..., n is i-th features component be made up of some structural feature faces.

8. the self-defined and recognition system of shape facility according to claim 1, is characterized in that: feature identifier identification any type shape facility, comprises the following steps:

S301: read in the feature templates intending the characteristic type identified from feature database;

S302: construct the 1st features component COM ₁, concrete steps comprise:

S3021: take out the 1st element fa in the attribute vector of structural feature face ₁=<NUM, TYPE, CONC, CONS>, find out type, concavity and convexity and other attribute and meet TYPE respectively, all piece surfaces of CONC and CONS regulation, and composition set FACES ₁; Wherein, NUM is the quantity in structural feature face in features component, is the quantification in structural feature face in features component when getting nonnegative integer, is the quantity in not structural feature face in limited features assembly when getting negative; TYPE is the type in structural feature face in features component, comprising: plane, the face of cylinder, circular conical surface, sphere, anchor ring, Extrude Face, the surfaces of revolution, fillet surface, hollows, offset plane, free form surface and type are not limit; CONC is the concavity and convexity in structural feature face in features component, comprising: plane, concave surface and convex surface; CONS is other constraint that in features component, structural feature face must meet, and comprising: surface level, dip plane, vertical plane and do not limit type;

S3022: take out only relevant with the 1st features component feature geometries restriction on the parameters, checks set FACES ₁in piece surface whether meet feature geometries restriction on the parameters, and from FACES ₁middle deletion does not meet the piece surface of constraint;

S3023: take out the element tgr formed in face topological and geometric relationship matrix _1,1, will FACES be gathered ₁be divided into some subsets: COM _1,1, COM _1,2..., COM _{1, m}, in each subset, the quantity of piece surface must meet the 1st element fa in the attribute vector of structural feature face ₁the regulation of middle NUM, and any one piece surface in each subset must meet tgr with some in this subset _1,1topology and the geometric relationship of regulation retrain;

S3024: the 1 features component COM ₁structure result be expressed as set RES ₁, i.e. formula (10):

${\mathrm{RES}}_1={\left\{\mathrm{FE}{A}_{1,j}\right\}}_{j=1}^m=\{<\mathrm{FEA}\_\mathrm{TYPE};{\mathrm{COM}}_{1,j}>{\}}_{j=1}^m---\left(10\right)$

S303: make i=2;

S304: if i>n, then go to step S306, wherein, n is the features component quantity of the type feature; Otherwise, make i-th features component COM _istructure result then, i-th features component COM is constructed _i, concrete steps are:

S3041: take out i-th element: fa in the attribute vector of structural feature face _i=<NUM, TYPE, CONC, CONS>, find out type, concavity and convexity and other attribute and meet TYPE respectively, all piece surfaces of CONC and CONS regulation, and composition set FACES _i;

S3042: make j=1;

S3043: if j>m, then go to step S305, wherein, m is i – 1 features component COM _i-1structure result RES _i-1in element number; Otherwise, take out RES _i-1in element FEA _{i-1, j};

S3044: take out the element tgr formed in face topological and geometric relationship matrix _{i, 1}~ tgr _{i, i-1}, check set FACES _iin each piece surface and FEA _{i-1, j}features component COM _k,j, k=1,2 ..., i – 1, in face between topological sum geometric relationship whether meet tgr _i,k, k=1,2 ..., i – 1, the constraint of regulation, and the piece surface of all satisfied constraints is formed new set FACES _i';

S3045: take out only relevant with 1st ~ i features component feature geometries restriction on the parameters, checks set FACES _i' in piece surface whether meet feature geometries restriction on the parameters, and from FACES _i' the middle piece surface deleting satisfied constraint;

S3046: take out the element tgr formed in face topological and geometric relationship matrix _i,i, will FACES be gathered _i' be divided into some subsets: COM _{i, 1}, COM _{i, 2}..., COM _i,p, in each subset, the quantity of piece surface meets i-th element fa in the attribute vector of structural feature face _ithe regulation of middle NUM, and any one piece surface in each subset must meet tgr with some in this subset _i,itopology and the geometric relationship of regulation retrain;

S3047: the i-th features component COM _istructure result be expressed as set RES _i, i.e. formula (11):

$\begin{array}{c}{\mathrm{RES}}_i={\mathrm{RES}}_{i}U{\left\{{\mathrm{FEA}}_{i,j}\right\}}_{j=1}^p\\ ={\mathrm{RES}}_{i}U{\{<\mathrm{FEA}\_\mathrm{TYPE};{\mathrm{COM}}_{1,j};...;{\mathrm{COM}}_{i,j}>\}}_{j=1}^p\\ =\{<\mathrm{FEA}\_\mathrm{TYPE};{\mathrm{COM}}_{1,j};...;{\mathrm{COM}}_{i,j}>{\}}_{j=1}^m\end{array}---\left(11\right)$

S3048: make j=j+1, goes to step S3043;

S305: make i=i+1, goes to step S304;

S306: examination characteristic cross-section attribute constraint: examination features component structure result RES _nin each element whether meet all characteristic cross-section attribute constraint, meet the element <FEA_TYPE of constraint; COM ₁; COM ₂; COM _n> is feature recognition result, that is: a features component COM ₁, COM ₂..., COM _nin to constitute a type be the shape facility of FEA_TYPE in all structural feature faces;

307: output characteristic recognition result.

9. the self-defined and recognition system of shape facility according to claim 8, is characterized in that: feature identifier examination <FEA_TYPE; COM ₁; COM ₂; COM _nthe step whether > meets certain characteristic cross-section attribute constraint comprises:

S3061: calculate COM ₁, COM ₂..., COM _nin the mean place of all structural feature faces center of area, it can be used as the initial point of property coordinate system;

S3062: the Z axis positive dirction determining property coordinate system: the features component of taking out the definition Z axis that characteristic cross-section attribute constraint specifies, if having plane in this assembly, then the outer method calculating this plane is vowed, and it can be used as Z axis positive dirction; If without plane in this assembly, then calculate the draw direction of Extrude Face or the turning axle direction of the surfaces of revolution, and it can be used as Z axis positive dirction; If both without plane in this assembly, also tensionless winkler foundation face and the surfaces of revolution, then the outer method in any face in this assembly that calculates is vowed, and it can be used as Z axis positive dirction;

S3063: the X-axis positive dirction determining property coordinate system: the features component of taking out the definition X-axis that characteristic cross-section attribute constraint specifies, if having plane in this assembly, then the outer method calculating this plane is vowed, and it can be used as X-axis positive dirction; If without plane in this assembly, then calculate the draw direction of Extrude Face or the turning axle direction of the surfaces of revolution, and it can be used as X-axis positive dirction; If both without plane in this assembly, also tensionless winkler foundation face and the surfaces of revolution, then the outer method in any face in this assembly that calculates is vowed, and it can be used as X-axis positive dirction;

S3064: the Y-axis positive dirction determining property coordinate system: according to Z axis positive dirction and X-axis positive dirction, according to right-handed coordinate system determination Y-axis positive dirction;

S3065: the coordinate plane AXIS_PLANE taking out the property coordinate system that characteristic cross-section attribute constraint specifies;

S3066: make i=1;

S3067: if the structural feature face quantity in the features component COM that specifies of characteristic cross-section attribute constraint is more than or equal to i, then takes out i-th structural feature face FACE in this assembly, turn S3068; Otherwise, character symbol contract bundle, the examination of this characteristic cross-section attribute constraint terminates;

S3068: structural feature face FACE and AXIS_PLANE coordinate plane ask friendship, if there is intersection L, then go to step S3069, otherwise go to step S30614;

S3069: all limits on the FACE of structural feature face and AXIS_PLANE coordinate plane ask friendship to obtain a series of intersection point, and judge the concavity and convexity of each intersection point;

S30610: intersection point is according to the name placement on intersection L;

S30611: delete all salient points except initial and end point;

S30612: the common edge between deletion structural feature face and the intersection point of AXIS_PLANE coordinate plane;

S30613: if the concave, convex point quantity in residue intersection point is discontented with the concave, convex point number constraint that sufficient characteristic cross-section attribute constraint specifies, then this feature does not meet constraint, and examination terminates, otherwise goes to step S30614;

S30614: make i=i+1, goes to step S3067.