CN104267663A - Aircraft structural part numerical control machining unit automatic construction method based on residual domain - Google Patents

Abstract

Provided is an aircraft structural part numerical control machining unit automatic construction method based on the residual domain, wherein a process scheme model and a machining chain model serve as the basis, and automatic construction and real-time supplement machining are conducted on a numerical control machining unit according to the machinable capacity of a tool on the basis of a residual model. The principle and the method are mainly achieved through the following steps of firstly, obtaining residual model information to conduct residual domain calculation; secondly, setting up a machinable domain and conducting automatic construction on the machining unit; thirdly, conducting machining operation selection; fourthly, conducting the real-time supplementary machining method. The machining concept based on the residual domain is established, the machining unit automatic construction process is deeply analyzed, and the real-time supplementary machining method is put forward so that it can be ensured that construction of the machining unit meets the process requirements and interference and overcut in the machining process are effectively reduced; by means of an automatic programming system machining program automatic generating module developed through the principle and the method, the workloads of man-machine interaction are remarkably reduced, and the numerical control program compiling and machining efficiency is improved.

Description

Automatic construction method of numerical control machining unit of airplane structural part based on residual domain

Technical Field

The invention provides an automatic construction method of a numerical control machining unit of an airplane structural member based on a residual domain, which is used for automatic construction and real-time complementary machining of the machining unit in an automatic programming module of a rapid numerical control programming system of the airplane complex structural member so as to realize automatic generation of a machining tool path program and belongs to the technical field of airplane digital intelligent machining.

Background

Currently, the general software is adopted to carry out numerical control programming, so that the long period, the low efficiency and the poor quality become bottlenecks which restrict the numerical control high-efficiency processing. The root cause of the disease is mainly the following two aspects: firstly, the process preparation and programming technology has low intelligentization degree and excessively depends on experience knowledge accumulated by process personnel for a long time in a specific production environment; secondly, the automation degree of the programming process is low, and various processing options and processing parameters need to be set in a man-machine interaction mode. Therefore, researching and developing an intelligent numerical control programming technology of a structural member and improving automation and intelligence level of numerical control machining programming are one of the main directions of future development of the efficient numerical control machining technology. In the whole machining programming of the structural part of the airplane, the interactive programming workload is large, the interactive operation is complicated, the machining operation creating and programming process belongs to, and the machining program is large and complex, the machining capability of a cutter cannot be fully exerted only by depending on the experience of a programmer, so that the machining efficiency is low, and the manufacturing cycle of the whole airplane is influenced.

Disclosure of Invention

In order to solve the problems, the invention provides an automatic construction method of a numerical control machining unit of an airplane structural part based on a residual domain; the method is based on a process scheme model and a processing chain model, automatically constructs a numerical control processing unit according to the processing capacity of a cutter on the basis of a residual model, and performs real-time complementary processing; the automatic generation module of the automatic programming system processing program developed by the invention can obviously reduce the workload of man-machine interaction and improve the programming and processing efficiency of the numerical control program.

The purpose of the invention is realized by the following technical scheme:

the automatic construction method of the numerical control machining unit of the airplane structural part based on the residual domain is characterized by comprising the following steps: 1) obtaining residual model information and calculating a residual domain; 2) establishing a workable field and automatically constructing a processing unit; 3) selecting a machining operation; 4) performing supplementary processing in real time;

the step 1) of obtaining residual model information specifically comprises: decomposing the domain elements into straight domain elements and curved domain elements to obtain residual domains, residual elements and layer residual elements;

the calculation of the residual domain mainly comprises (1) the calculation of the residual elements; and (2) the structure of the new layer of the residual element: given that r is a residual domain in any state in the process, o is a processing operation to be subsequently involved in processing, ω is an operation element processed by o, r forms a new residual domain r' after being processed by o, and ω is a layer residual element processed by oThe direct residue is r_p. The calculation of the residual field r' may be equivalent to r_pAfter omega is removedCalculating formed new residual elements;

the method for calculating the inter-residue comprises the following steps: ifAnd omega satisfyOrThenThe decomposition must be carried out as follows: (i) by plane p_ωbWill be provided withIs divided into inter-residues in Z directionAndand order(ii)Sequence update to inter-residue sequence② ifAnd omega satisfyOrThen order <math> <mrow> <msubsup> <mi>r</mi> <mrow> <mi>m</mi> <mn>1</mn> </mrow> <mi>i</mi> </msubsup> <mo>=</mo> <msubsup> <mi>r</mi> <mrow> <mi>p</mi> <mn>1</mn> </mrow> <mi>i</mi> </msubsup> <mo>-</mo> <mi>&omega;</mi> <mo>;</mo> </mrow> </math>

The new layer residue construction method comprises the following steps: sequence of meta-residuesThe number m of the residues is more than or equal to 2, and any two adjacent residues are takenAndi is more than or equal to 1 and less than or equal to m-1. Accordingly, the method for establishing the layer residual element structure specifically comprises the following steps: ifAndsatisfy the requirement ofThen mergeAndthe layer residue was constituted as follows: (i)bottom surface of (2)And(ii) fromRemoval in sequence② ifAndsatisfy the requirement ofThen no merging is performed;

step 2) the process of establishing a workable field and automatically constructing a processing unit comprises the following steps:

(1) layer work element calculation: extracting a straight residual element sequence and a layer residual element sequence in the domain element, and then automatically calculating the layer working element by adopting a secondary rolling method according to the machinable capacity of the cutter under given process conditions;

if the layer work element, use v_plExpressed, with the following parameterized representation:

$v_{p1}=(p_{\mathrm{vt}},z_{\mathrm{vt}},p_{\mathrm{vb}},z_{\mathrm{vb}},F_v(f_v^1,...,f_v^m){,r}_{p1})$

wherein p is_vtIs the top surface, p_vbIs a bottom surface, z_vt、z_vbRespectively a top surface p_vtAnd a bottom surface p_vbZ coordinate of center point, and p_vt||p_vb||XY，z_vt>z_vb，F_vThe combined surface field generated for projection of the layer-work elements onto the XY plane, i.e.And ism≥i≥1,m≥j≥1，r_plIs equal to v_plAssociated layer residue and r_pl∩v_pl＝v_pl(ii) a If the layer is an in-layer work element, use I_plRepresents, defined as:

I_pl＝(p_vt,z_vt,p_vb,z_vb,f_vI,r_pl)

wherein,and v is_plThe layer-internal work element sequence of Namely, it ism is more than or equal to i and more than or equal to 1, m is more than or equal to j and more than or equal to 1, andthen the following properties exist for the middle or inner workcell in the workable domain:

property 1 (perpendicular to Z-direction equal section) arbitrary two planes parallel to XY are respectively intersected with layer work element (or layer work element), and combined surface areas generated by respectively projecting intersection results to XY plane are respectively A₁，A₂If, ifAnd isThen A is₁＝A₂。

Properties 2 v_plBottom surface p_vbThe Z coordinate of the center point must be greater than or equal to its associated layer residual r_plBottom surface p_bZ coordinate of the centre point, i.e. Z_vb≥z_rb。

Property 3 (adjacency and monotonically increasing) settingIs r_pThe layer element sequence can be processed according to the cutter under the given process conditionN is more than or equal to 1 and less than or equal to m, the sequence satisfies the following conclusion: (a)1≤i≤n-1；(b)

(2) exercise and control deviceConstructing: and decomposing the layer project into a series of layer projects according to the definition of the layer project. And then, combining the layer internal work elements of the adjacent layers to generate a new layer internal work element according to the equal section judgment along the Z-axis direction. And finally, automatically calculating the operation elements according to the cutting depth and the layered processing technology of the cutter. Is provided withIs r_pFor two adjacent layer work elementsThe calculation method of the operation element comprises the following steps: (1) radial splitting: defining the layer work element according to the layer work elementDecomposing into layer work elements to obtain the layer work element sequenceAnd(2) axial merging: if it is notSatisfy the requirement of1≤j≤m_i，1≤k≤m_i+1Then mergeAndupdatingAnd fromIn the removal of(3) Axial splitting: if the current step is the layered rough machining or the layered supplement machining, thenPerforming axial decomposition according to the cutting depth of the cutter to obtain an operation element sequencem_ij≥1，1≤j≤m_iOtherwise, the layer worker element is directly used as the operation element.

(3) Creating a dummy: and after the operation elements are removed, converting the layer residual element sequence in the straight residual elements into an intermediate residual element sequence, and providing an intermediate model for the subsequent automatic calculation of the residual model.

(4) Layer residue construction: if the adjacent residual elements in the residual element sequence meet the equal cross section perpendicular to the Z direction, combining the residual elements until all the adjacent residual elements in the residual element sequence do not meet the combination requirement, namely completing the construction of a new layer residual element sequence and providing a residual model for the next processing step;

the machining operation selection in the step 3) refers to selecting machining operation for the operation element and calculating corresponding machining operation parameters, so that the construction of a machining unit can be completed; the machining operation adopted in the typical process step of the numerical control machining of the aircraft structural part is fixed, wherein the rough machining inner appearance and the finish machining web plate adopt Pocket machining operation; profile machining operation is adopted for corner machining, semi-finish machining inner appearance, finish machining inner appearance and cutting machining; the semi-fine/fine machining opening/closing angle is processed by Isoparmetric or Multi-axis Flank;

the real-time additional work method in the step 4): the method comprises the following four conditions of carrying out real-time complementary processing:

(1) adding the unprocessed allowance of the previous procedure:

let σ be a station, σ contain the sequence of processes λ₁,...,λ_c,...,λ_mC is more than or equal to 1 and less than or equal to m, m is the number of processing steps, lambda_cFor the current process, if the field element a is at λ₁,...,λ_c-1Sub-process sequence λ of₍₁₎,...,λ_(n)N is not less than 0 and not more than c-1 and is not processed in the working procedure lambda_cA is processed in the process lambda_cBefore processing, according to the working procedure sequence lambda₍₁₎,...,λ_(n)In (1), using the process lambda_cThe first tool of (1) performs complementary processing on the field element a.

(2) And (3) adding the incomplete machining allowance in the previous process:

let λ_cFor the current process, τ₁Is λ_cFirst process step of (a), t₁Is tau₁Cutting tools used, lambda_c-1Is λ_cThe pre-process of (2) is carried out,to go through the process lambda_c-1The straight residual after the processing is finished,is composed ofN is not less than 1, in which sequence the process lambda_c-1The sequence of sublayer residues formed by the process isM is more than or equal to 1 and less than or equal to n. According to the machining capability of the cutterWhether or not t is present in₁The workable field of (1). If present, at machining τ₁Front pairAnd (4) performing supplementary processing, namely, performing supplementary processing on the allowance of insufficient processing in the previous process.

(3) In the same process, the previous process step is not supplemented by the machining allowance: in the same process, a domain element possibly does not participate in any processing in the previous process step, and the previous process step needs to be subjected to complementary processing in the subsequent process step;

(4) in the same process, the previous process step is not supplemented with the complete machining allowance:

let λ_cIs a process, τ₁,τ₂Is λ_cTwo adjacent process steps of, t₁,t₂Are each tau₁,τ₂Corresponding cutting tools, a is a field element, a is in the process step tau₁Processed straight residue r_pLayer-by-layer sequence of residuesN is greater than or equal to 1, in the sequence, through process step tau₁Processing the resulting sequence of sublayer residuesa has a parent domain element sequence ofl is greater than or equal to 0, whereinIs thatI is more than or equal to 1 and less than or equal to l-1,in process step tau₁The straight residue after processing isLayer-by-layer sequence of residuesThe composition is that m is more than or equal to 1. According to t₂If in process step τ₂Can be processedOrJ is more than or equal to 1 and less than or equal to m, g is more than or equal to 1 and less than or equal to h, then tau is needed in the process step₂Before processing, the parent straight residual element or the own straight residual element is subjected to supplementary processing.

The automatic construction method of the numerical control machining unit of the airplane structural part based on the residual domain is characterized in that the residual model information comprises the following concepts;

(1) a work area: let p be the part, r be the blank, the excess material domain of r minus p is called the machining domain of part p, abbreviated as the domain, and denoted by σ.

(2) A domain element: decomposing the work domain according to a certain rule to obtain a series of mutually independent basic three-dimensional region units with parent-child relationship, wherein the units are called processing domain elements, which are called domain elements for short and are denoted by a.

(3) A direct domain element: a is a domain element, the profile side surface set of a and the island side surface set of a are projected to an XY plane along the Z-axis direction to obtain a series of plane domains f_p1,f_p2,…,f_pnN is more than or equal to 0, and the three-dimensional material domain formed between the constraint top surface and the constraint bottom surface of the domain element is stretched along the Z direction and is respectively v₁,v₂,…,v_nBalance ofFor straight field element, use v_pRepresents; a direct field element can also be represented asWherein p is_tIs the top surface, p_bIs a bottom surface, and p_t||p_b||XY，z_t、z_bRespectively a top surface p_tAnd a bottom surface p_bZ coordinate of center point, and Z_t>z_b；

(4) A bent domain element: scale a-v_pFor a curved region element, usev_sRepresents;

(5) contour boundary ring: v. the_pThe projection to the XY plane generates the surface area of f, mu_cFor bounding rings of contours

(6) Island boundary ring:is an island boundary ring, and m is more than or equal to 0

(7) A residual domain: after a series of processes, steps and processing operations, a residual unprocessed domain formed on the basis of the work domain is called a residual domain, which is called a residual domain for short, namely a residual model and is denoted by r;

(8) and (3) residue: the residual unprocessed domain unit formed after the domain element is processed by a series of processes, steps and processing operations is called residual element and is r_eRepresents; r is_e-v_sCalled the direct residue with r_pIs represented by_e-r_pCalled as starter residue, using r_sRepresents;

(9) layer residue: dividing the straight residual elements into a residual unit sequence from top to bottom along the Z-axis directionWherein,represents the parameterization of:

$r_{p1}^i=(p_{\mathrm{rt}}^i{,z}_{\mathrm{rt}}^i,p_{\mathrm{rb}}^i,z_{\mathrm{rb}}^i,F_r^i(r_r^{i,1},...,r_r^{i,n})),$

n≥1，m≥i≥1

wherein,is a top surface of the glass plate,is a bottom surface, and is provided with a plurality of grooves,are respectively top surfacesAnd a bottom surfaceZ coordinate of center point, and multiple mutually independent surface areas generated for projection of residual unit to XY planeThe resulting flat domain of the Boolean union operation is called the combined flat domain, i.e.And isi is greater than or equal to 1, n is greater than or equal to k is greater than or equal to 1, n is greater than or equal to j is greater than or equal to 1, ifSimultaneously, the following conditions are met: (1) perpendicular to the Z-direction equal cross section: arbitrarily take two planes p₁，z_p1≠z_p2，Projection of the intersection results with the planes p1, p2 onto the XY plane yields the combined area A₁，A₂Satisfies A₁＝A₂＝F_r ⁱ(ii) a (2) Adjacency:(3) monotonic increasing: indicating "true inclusion" then the residual unit is calledAs layer residues, sequences of residual unitsIs a sequence of layer residues.

An automatic construction method of a numerical control machining unit of an aircraft structural part based on a residual domain is characterized in that the residual domain, the residual elements and layer residual elements meet the following theorem and axiom:

theorem 1: at any state in the process (straight residue is not empty), the straight residue has one and only one layer residue sequence.

The axiom 1 is set as r as a residual domain,is a sequence of the residues of r,andare respectively asI is more than or equal to 1 and less than or equal to n,is composed ofLayer residue sequence of (1), m_iIf the ratio is more than or equal to 1, the following components are adopted:

the invention has the beneficial effects that: the automatic construction method of the airplane structural part numerical control machining unit based on the residual domain is based on the technological process and the machining capability of the cutter, the machining area of the cutter associated with each step is calculated in real time according to the overall technological process, meanwhile, the residual area is calculated, the machining unit of the cutter and the residual area to be machined can be accurately calculated, optimized sequencing is carried out according to the technological sequence, and finally, the automatic generation of the numerical control machining program of the structural part is realized. The method highly conforms to the actual technological process, can effectively avoid the problems of interference, over-cutting, residue and the like in the machining process, and lays a key technical foundation for realizing intelligent numerical control programming of the aircraft structural member.

Drawings

FIG. 1 is a schematic diagram of a work domain and a domain element.

FIG. 2 is a domain decomposition diagram.

FIG. 3 is a schematic diagram of straight and curved residues.

FIG. 4 is a diagram illustrating a layer residue sequence.

Fig. 5 is a schematic view of the working range of the tool in the 2.5-axis machining mode.

FIG. 6 is a schematic diagram of a layer worker and a layer worker.

FIG. 7 is a diagram illustrating inter-residue generation.

FIG. 8 is a domain meta-step model.

FIG. 9 is a schematic view of an automatic part machining process.

Fig. 10 is a schematic diagram of a rough machining process element a2 being rough machined in layers and being additionally machined before a finish machining process.

Fig. 11 is a schematic view showing that the rough machining step is not completely machined, and the finish machining step is performed by the supplementary hierarchical rough machining.

FIG. 12 is a schematic representation of the additional machining of the finished inner profile step to the web step for the unprocessed web.

FIG. 13 is a schematic diagram of the post process step and the pre process step in the same process.

Detailed Description

The following detailed description of the embodiments of the present invention is provided with reference to the accompanying drawings, which are implemented on the premise of the technical principles and methods of the present invention, and give detailed implementation manners and specific implementation procedures, but the scope of the present invention is not limited to the following implementation examples

The technical implementation principle of the automatic construction method of the numerical control machining unit of the airplane structural part based on the residual domain is as follows: 1) obtaining residual model information; 2) establishing a workable domain; 3) an automatic construction process of the processing unit; 4) and (5) adding a working method in real time.

Obtaining residual model information in the step 1), and establishing a concept of a residual model; the related concepts are defined as follows:

(1) a work area: let p be the part, r be the blank, and the excess material field obtained by subtracting p from r is called the machining field of the part p, abbreviated as the field, and denoted by σ, as shown in fig. 1 (a).

(2) A domain element: decomposing the work domain according to a certain rule to obtain a series of mutually independent basic three-dimensional region units with parent-child relationship, wherein the units are called processing domain elements, domain elements for short, and are denoted by a as shown in fig. 1 (b).

(3) A direct domain element: a is a domain element, the profile side surface set of a and the island side surface set of a are projected to an XY plane along the Z-axis direction to obtain a series of plane domains f_p1,f_p2,…,f_pnN is more than or equal to 0, and the three-dimensional material domain formed between the constraint top surface and the constraint bottom surface of the domain element is stretched along the Z direction and is respectively v₁,v₂,…,v_nBalance ofFor straight field element, use v_pAs shown in fig. 2; a direct field element can also be represented asWherein p is_tIs the top surface, p_bIs a bottom surface, and p_t||p_b||XY，z_t、z_bRespectively a top surface p_tAnd a bottom surface p_bZ coordinate of center point, and Z_t>z_b；

(4) A bent domain element: scale a-v_pFor a bent element, use v_sAs shown in fig. 2;

(5) contour boundary ring: v. the_pThe projection to the XY plane generates the surface area of f, mu_cFor bounding rings of contours

(6) Island boundary ring:is an island boundary ring, and m is more than or equal to 0

(7) A residual domain: after a series of processes, steps and machining operations, a residual unprocessed domain, called residual domain, or residual model for short, is formed on the basis of the process domain, and is denoted by r, as shown in fig. 3;

(8) and (3) residue: the residual unprocessed domain unit formed after the domain element is processed by a series of processes, steps and processing operations is called residual element and is r_eRepresents; r is_e-v_sCalled the direct residue with r_pIs represented by_e-r_pCalled as starter residue, using r_sRepresents; as shown in fig. 3

(9) Layer residue: dividing the straight residual elements into a residual unit sequence from top to bottom along the Z-axis directionWherein,represents the parameterization of:

$r_{p1}^i=(p_{\mathrm{rt}}^i{,z}_{\mathrm{rt}}^i,p_{\mathrm{rb}}^i,z_{\mathrm{rb}}^i,F_r^i(f_r^{i,1},...,f_r^{i,n})),$

n≥1，m≥i≥1

wherein,is a top surface of the glass plate,is a bottom surface, and is provided with a plurality of grooves,are respectively top surfacesAnd a bottom surfaceZ coordinate of center point, and multiple mutually independent surface areas generated for projection of residual unit to XY planeThe resulting flat domain of the Boolean union operation is called the combined flat domain, i.e.And isi is greater than or equal to 1, n is greater than or equal to k is greater than or equal to 1, n is greater than or equal to j is greater than or equal to 1, ifSimultaneously, the following conditions are met: (1) perpendicular to the Z-direction equal cross section: arbitrarily take two planes p₁，z_p1≠z_p2，Projection of the intersection results with the planes p1, p2 onto the XY plane yields the combined area A₁，A₂Satisfies A₁＝A₂＝F_r ⁱ(ii) a (2) Adjacency:(3) monotonic increasing: indicating "true inclusion" then the residual unit is calledAs layer residues, sequences of residual unitsIs a sequence of layer residues. As shown in fig. 4The above definition is satisfied and, therefore,all are layer residues.

The purpose of making the machinable domain in the step 2) is to accurately describe the construction of the machining unit based on the residual domain, and the related terms of the machinable domain of the tool are defined as follows:

(1) the method comprises the following steps: depending on the machining capacity of the tool, given the machining area and other process conditions, the area of material that can be removed by the tool is called the machinable area, called simply the machinable area, by v_mExpressed, formally defined as follows:

v_m＝(v,f,d,l,l_s,_p,_e)

wherein v is the processing area, f is the processing mode, d is the diameter of the cutter, l is the lower cutting depth of the cutter, l_sThe safe distance between the lower edge of the tool shank and the top surface of the current machining feature,_ais the axial allowance of the axial direction,_ris the lateral allowance; as shown in FIG. 5, in the 2.5-axis machining method, the workable field of the tool is v_mAnd due to insufficient axial machining capability of the cutter, actual axial allowance is caused'_a>_a。

(2) Layer construction element: knowing the process characteristic type, tool, lateral allowance and axial allowance of the step processing, the workable field of the layer residual element under the 2.5-axis processing mode is called layer element and is v_plExpressed, with the following parameterized representation:

$v_{p1}=(p_{\mathrm{vt}},z_{\mathrm{vt}},p_{\mathrm{vb}},z_{\mathrm{vb}},F_v(f_v^1,...,f_v^m){,r}_{p1})$

wherein p is_vtIs the top surface, p_vbIs a bottom surface, z_vt、z_vbRespectively a top surface p_vtAnd a bottom surface p_vbZ coordinate of center point, and p_vt||p_vb||XY，z_vt>z_vb，F_vThe combined surface field generated for projection of the layer-work elements onto the XY plane, i.e.And ism≥i≥1,m≥j≥1，r_plIs equal to v_plAssociated layer residue and r_pl∩v_pl＝v_pl；

(3) Layer internal work element: if m is more than or equal to 2, the layer member can be divided into m mutually independent areas in the three-dimensional spaceDomain units, called intralayer workers, with I_plRepresents, defined as:

I_pl＝(p_vt,z_vt,p_vb,z_vb,f_vI,r_pl)

wherein,and v is_plThe layer-internal work element sequence of Namely, it ism is more than or equal to i and more than or equal to 1, m is more than or equal to j and more than or equal to 1, andfor example, as shown in FIG. 6, r_plFor finishing the layer residue formed after the web, the cutter is at r during corner machining_plThe middle layer of the machinable workpiece is v_plComprises four layer internal work elements

(4) Multiple operation elements: dividing the in-layer working element into a plurality of operation elements by taking the cutting depth as a layering basis in the axial direction, and selecting one processing operation for each operation element to process;

(5) a single operation unit: directly taking the in-layer working element as an operation element, selecting one machining operation, and setting an axial layering parameter in machining operation parameters to realize axial layering machining;

(6) residue replacement: when a straight residual element is processed into an operation element, the bottom surface of the operation element is divided by the layer residual element to generate one or more independent residual bodies, and the residual bodies are called as middle residual elementsThe "meta-residue" is abbreviated as meta-residue. The straight residue shown in FIG. 4 is a layer residueThe construction is such that after the removal of the operation element omega, the residual element shown in FIG. 7 is obtainedAnd

the automatic construction process of the processing unit in step 3) is developed based on the above concept, the processing unit construction based on the residual domain is performed by firstly, aiming at a single domain element, providing a domain element step model, which is an operation element calculation process that a tool can process in one domain element based on the residual under the given process condition, as shown in fig. 8, the main process is as follows:

(1) layer work element calculation: and extracting a straight residual element sequence and a layer residual element sequence in the domain element, and then automatically calculating the layer working element by adopting a secondary rolling method according to the machinable capacity of the cutter under the given process condition.

(2) The operation element structure: and decomposing the layer project into a series of layer projects according to the definition of the layer project. And then, combining the layer internal work elements of the adjacent layers to generate a new layer internal work element according to the equal section judgment along the Z-axis direction. And finally, automatically calculating the operation elements according to the cutting depth and the layered processing technology of the cutter.

(3) Creating a dummy: and after the operation elements are removed, converting the layer residual element sequence in the straight residual elements into an intermediate residual element sequence, and providing an intermediate model for the subsequent automatic calculation of the residual model.

(4) Layer residue construction: and if the adjacent residual elements in the residual element sequence meet the equal section perpendicular to the Z direction, combining the residual elements until all the adjacent residual elements in the residual element sequence do not meet the combination requirement, namely completing the construction of a new layer residual element sequence and providing a residual model for the next processing step.

It is easy to know that in the whole process of processing the blank into the part, each domain element needs to pass through a plurality of domain element steps. When all field elements are machined, a plurality of geometric features are formed, and the final part is formed by the geometric features, so that the automatic machining of the part is completed, as shown in fig. 9 (a). Further, from the perspective of the overall process, the execution of the field element step is as shown in fig. 9(b), and each process step is to perform a plurality of field element step calculations to generate a plurality of processing units. Furthermore, in order to avoid interference and over-cutting in the machining process and meet the requirement of automatic machining based on a process scheme, real-time complementary machining is provided to remove residual areas which are not fully machined or not machined at all due to insufficient machining capacity of a cutter in the preorder process.

The real-time complementary processing method in the step 4) carries out real-time complementary processing aiming at the following four conditions:

(1) adding tool for unprocessed allowance of former procedure

Let σ be a station, σ contain the sequence of processes λ₁,...,λ_c,...,λ_mC is more than or equal to 1 and less than or equal to m, m is the number of processing steps, lambda_cFor the current process, if the field element a is at λ₁,...,λ_c-1Sub-process sequence λ of₍₁₎,...,λ_(n)N is not less than 0 and not more than c-1 and is not processed in the working procedure lambda_cA is processed in the process lambda_cBefore processing, according to the working procedure sequence lambda₍₁₎,...,λ_(n)In (1), using the process lambda_cThe first tool of (1) performs complementary processing on the field element a. As shown in FIG. 10, a₁And a₂Two field elements and a father-son relationship, the rough machining process only has one step, and the step tool is t₁，t₁Associating only a₁Not relating to a₂In this step, a₁Is processed omega₁₁、ω₁₂And omega₁₃，a₂No processing was performed. In the finish machining process, the first step is a web finish machining step, and the cutter is t₂，t₂Association a₁And a₂Due to a₂Is not roughly processed, therefore, t is used first₂Omega removal by layered rough machining₂₁，ω₂₂Web re-processing omega₂₃And omega₁₄。ω₂₁，ω₂₂I.e. a is not processed in the previous process₂And (5) implementing additional work.

(2) Additional tools not completely processed in the former process

Let λ_cFor the current process, τ₁Is λ_cFirst process step of (a), t₁Is tau₁Cutting tools used, lambda_c-1Is λ_cThe pre-process of (2) is carried out,to go through the process lambda_c-1The straight residual after the processing is finished,is composed ofN is not less than 1, in which sequence the process lambda_c-1The sequence of sublayer residues formed by the process isM is more than or equal to 1 and less than or equal to n. According to the machining capability of the cutterWhether or not there is a workable field of t 1. If present, at machining τ₁Front pairAnd (4) performing supplementary processing, namely, performing supplementary processing on the allowance of insufficient processing in the previous process. As shown in fig. 11, the field element a is processed by layer ω in the rough process₁₁，ω₁₂And omega₁₃Forming a layer residueAndthe straight residue element is formed. Wherein,is a layer residue directly formed by a rough machining process. In the fine machining process, the radial allowance of the web machining step is the same as that of rough machining, and the diameter of the cutter is smaller than that of the rough machining cutter. To avoid machining interference, the web is machined before the machining stepComplement processing of omega₂₁，ω₂₂，ω₂₃Working web omega₂₄。

(3) In the same process, the additional work of the unprocessed allowance in the previous process step

Similar to the previous process without the additional machining of the machining allowance, in the same process, there may be a field element not participating in any machining in the previous process step, and the previous process step needs to be additionally machined in the subsequent process step. As shown in FIG. 12, in the finishing step, the finishing web step has no tool machining layer stubAndthere is the incomplete yuan of cutter related layer in the finish machining inside and outside shape process stepAndthe field element is located, at this time, the operation element omega is processed first₂₁For repairing web and processing operation element omega₂₂And realizing the finish machining of the inner appearance.

(4) In the same process, the previous process step is not completely added with the allowance

Let λ_cIs a process, τ₁,τ₂Is λ_cTwo adjacent process steps of, t₁,t₂Are each tau₁,τ₂Corresponding cutting tools, a is a field element, a is in the process step tau₁Processed straight residue r_pLayer-by-layer sequence of residuesN is greater than or equal to 1, in the sequence, through process step tau₁Processing the resulting sequence of sublayer residuesa has a parent domain element sequence ofl is greater than or equal to 0, whereinIs thatI is more than or equal to 1 and less than or equal to l-1,in process step tau₁The straight residue after processing isLayer-by-layer sequence of residuesThe composition is that m is more than or equal to 1. According to t₂If in process step τ₂Can be processedOrJ is more than or equal to 1 and less than or equal to m, g is more than or equal to 1 and less than or equal to h, then tau is needed in the process step₂Before processing, the parent straight residual element or the own straight residual element is subjected to supplementary processing. As shown in fig. 13, τ₁,τ₂Two adjacent process steps of the rough machining process, the machining allowance is the same, d₁，d₂Is t₁，t₂Diameter of the tool a₁Is a₂The parent domain element of (2). Wherein, t₁Association a₁，t₂Association a₂And d is₁>d₂. In process step tau₁，t₁The operating element of the processing is omega₁₁，ω₁₂And omega₁₃At process step τ₂，t₂First processing a₁Operating element omega of₁₄，ω₁₅And ω₁₆Reprocessing omega₂₁And ω₂₂Wherein ω is₁₄And ω₁₅，ω₁₆A working step tau for the same process₂To the previous process step tau₁And (5) supplementing the operation elements for processing.

Based on the principle, the general technical implementation method of the invention comprises the following steps: 1) calculating a residual domain; 2) calculating an operation element; 3) and selecting the machining operation.

The residual domain calculation in the step 1) means that known r is a residual domain in any state in the process, o is a processing operation needing to be processed immediately, omega is an operation element processed by o, r forms a new residual domain r' after being processed by o, and a layer residual element processed by omega isThe direct residue is r_p. The calculation of the residual field r' may be equivalent to r_pThe calculation of new residual elements formed after removing omega mainly comprises the calculation of residual elements between (1) and the construction of new (2) layers of residual elements.

(1) And (3) computing the residual elements:the relation between the vector and omega is shown in Table 1, i is more than or equal to 1 and less than or equal to n, and the inter-residue calculation method is established according to the relation: ifAnd omega satisfyOrThenThe decomposition must be carried out as follows: (i) by plane p_ωbWill be provided withIs divided into inter-residues in Z directionAndand order(ii)Sequence update to inter-residue sequence② ifAnd omega satisfyOrThen order

(2) Layer residue structure: sequence of meta-residuesThe number m of the residues is more than or equal to 2, and any two adjacent residues are takenAndi is more than or equal to 1 and less than or equal to m-1. Defined by meta-elementsAndthe relationship between them is shown in Table 2. Accordingly, the method for establishing the layer residual element structure specifically comprises the following steps: ifAndsatisfy the requirement ofThen mergeAndthe layer residue was constituted as follows: (i)bottom surface of (2)And(ii) fromRemoval in sequence② ifAndsatisfy the requirement ofNo merging is performed.

The operation element calculation in the step 2) is the settingIs r_pFor two adjacent layer work elementsThe calculation method of the operation element comprises the following steps: (1) radial splitting: defining the layer work element according to the layer work elementDecomposing into layer work elements to obtain the layer work element sequenceAnd(2) axial merging: if it is notSatisfy the requirement of1≤j≤m_i，1≤k≤m_i+1Then mergeAndupdatingAnd fromIn the removal of(3) Axial splitting: if the current step is the layered rough machining or the layered supplement machining, thenPerforming axial decomposition according to the cutting depth of the cutter to obtain an operation element sequencem_ij≥1，1≤j≤m_iOtherwise, the layer worker element is directly used as the operation element.

The processing operation selection in the step 3) refers to selecting processing operation for the operation element and calculating corresponding processing operation parameters, so that the processing unit construction can be completed. Because the numerical control machining process of the aircraft structural part is mature, the machining operation adopted in the typical process step is relatively fixed, as shown in table 3.

Tables 1-3 above are as follows:

TABLE 1 construction of the residues

Table 2 layer residual construction

TABLE 3 selection of machining operations for typical Process steps

Typical working procedure	Machining operations	Typical working procedure	Machining operations
				Roughing	Pocket	Semi-finish/finish internal profile	Profile
Finish machining web	Pocket	Semi-finish/finish machining opening and closing angle	Multi-Axis Flank or Isoparametric
				Corner machining	Profile	Cutting process	Profile

Claims (3)

1. The automatic construction method of the numerical control machining unit of the airplane structural part based on the residual domain is characterized by comprising the following steps: 1) obtaining residual model information and calculating a residual domain; 2) establishing a workable field and automatically constructing a processing unit; 3) selecting a machining operation; 4) performing supplementary processing in real time;

the step 1) of obtaining residual model information specifically comprises: decomposing the domain elements into straight domain elements and curved domain elements to obtain residual domains, residual elements and layer residual elements;

the calculation of the residual domain mainly comprises (1) the calculation of the residual elements; and (2) newConstruction of layer stumps: given that r is a residual domain in any state in the process, o is a processing operation to be subsequently involved in processing, ω is an operation element processed by o, r forms a new residual domain r' after being processed by o, and ω is a layer residual element processed by oThe direct residue is r_p(ii) a The calculation of the residual field r' may be equivalent to r_pCalculating new residual elements formed after omega is removed;

the method for calculating the inter-residue comprises the following steps: ifAnd omega satisfyOrThenThe decomposition must be carried out as follows: (i) by plane p_ωbWill be provided withIs divided into inter-residues in Z directionAndand order(ii)Sequence update to inter-residue sequence② ifAnd omega satisfyOrThen order <math> <mrow> <msubsup> <mi>r</mi> <mrow> <mi>m</mi> <mn>1</mn> </mrow> <mi>i</mi> </msubsup> <mo>=</mo> <msubsup> <mi>r</mi> <mrow> <mi>p</mi> <mn>1</mn> </mrow> <mi>i</mi> </msubsup> <mo>-</mo> <mi>&omega;</mi> <mo>;</mo> </mrow> </math>

The new layer residue construction method comprises the following steps: sequence of meta-residuesThe number m of the residues is more than or equal to 2, and any two adjacent residues are takenAndi is more than or equal to 1 and less than or equal to m-1; accordingly, the method for establishing the layer residual element structure specifically comprises the following steps: ifAndsatisfy the requirement ofThen mergeAndthe layer residue was constituted as follows: (i)bottom surface of (2)And(ii) fromRemoval in sequence② ifAndsatisfy the requirement ofThen no merging is performed;

step 2) the process of establishing a workable field and automatically constructing a processing unit comprises the following steps:

(1) layer work element calculation: extracting a straight residual element sequence and a layer residual element sequence in the domain element, and then automatically calculating the layer working element by adopting a secondary rolling method according to the machinable capacity of the cutter under given process conditions;

if the layer work element, use v_plRepresentation, with the following parameterized representation：

$v_{p1}=(p_{\mathrm{vt}},z_{\mathrm{vt}},p_{\mathrm{vb}},z_{\mathrm{vb}},F_v(f_v^1,...,f_v^m){,r}_{p1})$

Wherein p is_vtIs the top surface, p_vbIs a bottom surface, z_vt、z_vbRespectively a top surface p_vtAnd a bottom surface p_vbZ coordinate of center point, and p_vt||p_vb||XY，z_vt>z_vb，F_vThe combined surface field generated for projection of the layer-work elements onto the XY plane, i.e.And ism≥i≥1，m≥j≥1，r_plIs equal to v_plAssociated layer residue and r_pl∩v_pl＝v_pl(ii) a If the layer is an in-layer work element, use I_plRepresents, defined as:

I_pl＝(p_vt,z_vt,p_vb,z_vb,f_vI,r_pl)

wherein,and v is_plThe layer-internal work element sequence of Namely, it ism is more than or equal to i and more than or equal to 1, m is more than or equal to j and more than or equal to 1, andthen the following properties exist for the middle or inner workcell in the workable domain:

property 1 (perpendicular to Z-direction equal section) arbitrary two planes parallel to XY are respectively intersected with layer work element (or layer work element), and combined surface areas generated by respectively projecting intersection results to XY plane are respectively A₁，A₂If, ifAnd isThen A is₁＝A₂；

Properties 2 v_plBottom surface p_vbThe Z coordinate of the center point must be greater than or equal to its associated layer residual r_plBottom surface p_bZ coordinate of the centre point, i.e. Z_vb≥z_rb；

Property 3 (adjacency and monotonically increasing) settingIs r_pThe layer element sequence can be processed according to the cutter under the given process conditionN is more than or equal to 1 and less than or equal to m, the sequence satisfies the following conclusion: (a)1≤i≤n-1；(b)

(2) the operation element structure: decomposing the layer work element into a series of layer work elements according to the definition of the layer work elements; then, combining the layer internal work elements of adjacent layers to generate a new layer internal work element according to the equal section judgment along the Z-axis direction; finally, automatically calculating an operation element according to the cutting depth and the layered processing technology of the cutter; is provided withIs r_pFor two adjacent layer work elementsThe calculation method of the operation element comprises the following steps: (1) radial splitting: defining the layer work element according to the layer work elementDecomposing into layer work elements to obtain the layer work element sequenceAnd(2) axial merging: if it is notSatisfy the requirement of1≤j≤m_i，1≤k≤m_i+1Then mergeAndupdatingAnd fromIn the removal of(3) Axial splitting: if the current step is the layered rough machining or the layered supplement machining, thenPerforming axial decomposition according to the cutting depth of the cutter to obtain an operation element sequencem_ij≥1，1≤j≤m_iOtherwise, the in-layer worker element is directly used as an operation element;

(3) creating a dummy: after the operation elements are removed, a layer residual element sequence in the straight residual elements is converted into an intermediate residual element sequence, and an intermediate model is provided for the automatic calculation of a subsequent residual model;

(4) layer residue construction: if the adjacent residual elements in the residual element sequence meet the equal cross section perpendicular to the Z direction, combining the residual elements until all the adjacent residual elements in the residual element sequence do not meet the combination requirement, namely completing the construction of a new layer residual element sequence and providing a residual model for the next processing step;

the machining operation selection in the step 3) refers to selecting machining operation for the operation element and calculating corresponding machining operation parameters, so that the construction of a machining unit can be completed; the machining operation adopted in the typical process step of the numerical control machining of the aircraft structural part is fixed, wherein the rough machining inner appearance and the finish machining web plate adopt Pocket machining operation; profile machining operation is adopted for corner machining, semi-finish machining inner appearance, finish machining inner appearance and cutting machining; the semi-fine/fine machining opening/closing angle is processed by Isoparmetric or Multi-axis Flank;

the real-time additional work method in the step 4): the method comprises the following four conditions of carrying out real-time complementary processing:

(1) adding the unprocessed allowance of the previous procedure:

let σ be a station, σ contain the sequence of processes λ₁,...,λ_c,...,λ_mC is more than or equal to 1 and less than or equal to m, m is the number of processing steps, lambda_cFor the current process, if the field element a is at λ₁,...,λ_c-1Sub-process sequence λ of₍₁₎,...,λ_(n)N is not less than 0 and not more than c-1 and is not processed in the working procedure lambda_cA is processed in the process lambda_cBefore processing, according to the working procedure sequence lambda₍₁₎,...,λ_(n)In (1), using the process lambda_cThe first cutter carries out complementary processing on the field element a;

(2) and (3) adding the incomplete machining allowance in the previous process:

let λ_cFor the current process, τ₁Is λ_cFirst process step of (a), t₁Is tau₁Cutting tools used, lambda_c-1Is λ_cThe pre-process of (2) is carried out,to go through the process lambda_c-1The straight residual after the processing is finished,is composed ofN is not less than 1, in which sequence the process lambda_c-1Is processed to formHas a sequence of sub-layer residues ofM is more than or equal to 1 and less than or equal to n; according to the machining capability of the cutterWhether or not t is present in₁A workable field of; if present, at machining τ₁Front pairPerforming supplementary processing, namely performing supplementary processing on the allowance of insufficient processing in the previous procedure;

(3) in the same process, the previous process step is not supplemented by the machining allowance: in the same process, a domain element possibly does not participate in any processing in the previous process step, and the previous process step needs to be subjected to complementary processing in the subsequent process step;

(4) in the same process, the previous process step is not supplemented with the complete machining allowance:

let λ_cIs a process, τ₁,τ₂Is λ_cTwo adjacent process steps of, t₁,t₂Are each tau₁,τ₂Corresponding cutting tools, a is a field element, a is in the process step tau₁Processed straight residue r_pLayer-by-layer sequence of residuesN is greater than or equal to 1, in the sequence, through process step tau₁Processing the resulting sequence of sublayer residuesa has a parent domain element sequence ofl is greater than or equal to 0, whereinIs thatI is more than or equal to 1 and less than or equal to l-1,in process step tau₁The straight residue after processing isLayer-by-layer sequence of residuesThe composition is that m is more than or equal to 1; according to t₂If in process step τ₂Can be processedOrJ is more than or equal to 1 and less than or equal to m, g is more than or equal to 1 and less than or equal to h, then tau is needed in the process step₂Before processing, the parent straight residual element or the own straight residual element is subjected to supplementary processing.

2. The automatic construction method of numerical control machining unit of aircraft structural member based on residual domain as claimed in claim 1, characterized in that the residual model information comprises the following concepts;

(1) a work area: setting p as a part and r as a blank, and using a redundant material domain obtained by subtracting p from r as a processing domain of the part p, namely a working domain for short, and expressing the domain by sigma;

(2) a domain element: decomposing the work domain according to a certain rule to obtain a series of mutually independent basic three-dimensional area units with parent-child relationship, wherein the units are called processing domain elements, called domain elements for short and denoted by a;

(3) a direct domain element: a is a domain element, the profile side surface set of a and the island side surface set of a are projected to an XY plane along the Z-axis direction to obtain a series of plane domains f_p1,f_p2,…,f_pnN is not less than 0, and is stretched in the Z directionThe three-dimensional material domain formed between the constraint top surface and the constraint bottom surface of the domain element is v₁,v₂,…,v_nBalance ofFor straight field element, use v_pRepresents; a direct field element can also be represented asWherein p is_tIs the top surface, p_bIs a bottom surface, and p_t||p_b||XY，z_t、z_bRespectively a top surface p_tAnd a bottom surface p_bZ coordinate of center point, and Z_t>z_b；

(4) A bent domain element: scale a-v_pIs a curved field element and is expressed by vs;

(5) contour boundary ring: v. the_pThe projection to the XY plane generates the surface area of f, mu_cFor bounding rings of contours

(6) Island boundary ring:is an island boundary ring, and m is more than or equal to 0

(7) A residual domain: after a series of processes, steps and processing operations, a residual unprocessed domain formed on the basis of the work domain is called a residual domain, which is called a residual domain for short, namely a residual model and is denoted by r;

(8) and (3) residue: the residual unprocessed domain unit formed after the domain element is processed by a series of processes, steps and processing operations is called residual element and is r_eRepresents; r is_e-v_sCalled the direct residue with r_pIs represented by_e-r_pCalled the starter residue, denoted by rs;

(9) layer residue: dividing the straight residual elements into a residual unit sequence from top to bottom along the Z-axis directionWherein,represents the parameterization of:

$r_{p1}^i=(p_{\mathrm{rt}}^i{,z}_{\mathrm{rt}}^i,p_{\mathrm{rb}}^i,z_{\mathrm{rb}}^i,F_r^i(r_r^{i,1},...,r_r^{i,n})),$

n≥1，m≥i≥1

wherein,is a top surface of the glass plate,is a bottom surface, and is provided with a plurality of grooves,are respectively asThe top surfaceAnd a bottom surfaceZ coordinate of center point, and multiple mutually independent surface areas generated for projection of residual unit to XY planeThe resulting flat domain of the Boolean union operation is called the combined flat domain, i.e.And isi is greater than or equal to 1, n is greater than or equal to k is greater than or equal to 1, n is greater than or equal to j is greater than or equal to 1, ifSimultaneously, the following conditions are met: (1) perpendicular to the Z-direction equal cross section: arbitrarily take two planes p₁，z_p1≠z_p2，Projection of the intersection results with the planes p1, p2 onto the XY plane yields the combined area A₁，A₂Satisfies A₁＝A₂＝F_r ⁱ(ii) a (2) Adjacency:(3) monotonic increasing: indicating "true inclusion" then the residual unit is calledAs layer residues, sequences of residual unitsIs a sequence of layer residues.

3. The automatic construction method of the numerical control machining unit for the aircraft structural part based on the residual domain as claimed in claim 1, wherein the residual domain, the residual element and the layer residual element satisfy the following theorem and axiom:

theorem 1: in any state (the straight residue is not empty) in the process, the straight residue has one and only one layer residue sequence;

the axiom 1 is set as r as a residual domain,is a sequence of the residues of r,andare respectively asI is more than or equal to 1 and less than or equal to n,is composed ofLayer residue sequence of (1), m_iIf the ratio is more than or equal to 1, the following components are adopted: