Airship soft structure component intersection line unfolding method based on CATIA secondary development

Abstract

The application discloses a method for developing airship soft structure component intersection line based on CATIA secondary development, and comprises the following steps: establishing a coordinate system in CATIA after completing the planar piece design of the airbag; performing affine processing on the standard piece of the airship airbag in CATIA; joining all the pieces after the affine processing; taking a feature point A on the intersection line of the airbag and the auxiliary airbag at an arbitrary ratio to determine the development point of the feature point A on the intersection line; obtaining the development result of all the points on the intersection line by editing a macro insertion loop; connecting the development points of all the feature points by using a spline curve; and moving the intersection line to the corresponding piece to obtain the intersection line of each component. The method improves the intersection line development efficiency and intuitiveness of the airship soft structure component, simultaneously makes up for the shortcomings of the airship soft airbag piece that cannot be generated by the traditional axial arc length integral method, and is suitable for the intersection line piece design of each component of the airship.

Description

TECHNICAL FIELD

[0001] The application relates to the field of aircraft production and manufacturing, in particular to a method for unfolding intersection lines of soft structure components of airships based on secondary development of CATIA. BACKGROUND

[0002] In the process of designing curved surface patches of soft structure components of airships, the curved surface needs to be divided into several identical sub-curved surfaces, and then each sub-curved surface is unfolded into a standard patch, as shown in the drawing. Figure 1 When the design of the planar patch is completed, the intersection lines between the components of the airship need to be calculated, as shown in the drawing. Figure 2 The accuracy of the intersection line calculation directly determines the accuracy of the installation position between the components of the airship.

[0003] In the traditional intersection line unfolding process, the axial arc length integral method is adopted, and the intersection line between the airbag and the auxiliary airbag is taken as an example. Figure 3 As shown in the drawing, for any point A on the intersection line, the x value after unfolding is obtained by using arc length integral, that is, the length of curve m. (r is the radius of the cross section circle of the airbag passing through point A, and cps is the selected patch number) to obtain the y value, that is, the length of curve l.

[0004] In the actual calculation process, the length of curve m cannot be obtained by definite integral, and the variable step trapezoidal integration method is usually used to divide the integral interval m into n equal parts, and then the integral value is obtained by using the following formula:

[0005]

[0006] The method has the disadvantages of high time consumption and poor intuitiveness. When the airbag generatrix equation is complex or cannot be described by an analytical expression, the traditional axial arc length integral method cannot be used to obtain the length of curve m, that is, the intersection line of the airship cannot be solved. SUMMARY

[0007] The application aims to provide a method for unfolding intersection lines of soft structure components of airships based on secondary development of CATIA to overcome the problems in the prior art.

[0008] To achieve the above-mentioned task, the application adopts the following technical solutions:

[0009] A method for unfolding intersection lines of soft structure components of airships based on secondary development of CATIA, after the design of the planar patch of the airbag is completed, the following steps are performed:

[0010] establishing a coordinate system in CATIA;

[0011] Affine the standard patches of the airship envelope in CATIA by 2, 4, 6, 8…n times respectively; join all the patches formed after the affine operation;

[0012] Take a feature point A on the intersection line of the envelope and the sub-envelope at an arbitrary ratio;

[0013] Draw a plane through A Parallel to the yz plane, the plane Divide the intersection line of the envelope with the plane at the point A into a straight line l, pull up the straight line l by h1 in the x direction, and develop it in the y direction on the xy plane to take the extreme value in the y direction; draw a plane through A and the x axis Draw a plane Divide the intersection line of the envelope with the plane at the point A into a straight line m, draw a plane through the point A The normal line of the plane, pull up the straight line m by h2 in the normal direction, and develop it in the x direction on the xy plane to take the extreme value in the x direction; intersect the two extreme values, and the intersection point is A';

[0014] Draw a straight line a through A' in the y direction, intersect all the joints before, take the point B closest to A', divide the straight line a at the point B to obtain the straight line BA', draw the intersection point B' of the straight line BA' and the standard patch, and perform a point-to-point translation to move the starting point of the straight line BA' to B', and the terminal point A'' is the developed point of the point A on the final intersection line;

[0015] Connect all the developed points of the feature points with a spline curve, and then move the intersection line to the corresponding patch to obtain the intersection line of each component.

[0016] Further, the origin of the coordinate system is at the front end point of the airship envelope, the x axis points to the tail of the envelope along the axial direction of the envelope, the y axis points to the upper side of the envelope perpendicularly to the x axis, and the z axis is determined by the right-hand rule.

[0017] Further, the method further comprises: hiding all points, lines and surfaces except the point A''.

[0018] Further, the specific operation of the affine operation is: keeping the x axis coordinate of the standard patch unchanged, and expanding the y axis coordinate of the standard patch by 2, 4, 6, 8…n times to form the patch.

[0019] Further, h1=20mm and h2=20mm.

[0020] Further, to edit a macro with CATIA secondary development, only the developed x and y coordinates of the feature point A need to be drawn, and then a loop statement is inserted to obtain the developed results of all feature points on the intersection line.

[0021] Further, before taking a feature point A on the intersection line of the airbag and the auxiliary airbag at an arbitrary ratio, the method further comprises starting macro recording.

[0022] After hiding the points, lines and surfaces except the point A'', the method further comprises:

[0023] Ending macro recording to generate a VBscript language;

[0024] Adding and changing the loop statement of the VBscript language, setting the ratio of the feature point and the number of the feature points taken on the intersection line, and running the program.

[0025] A terminal device comprising a processor, a memory and a computer program stored in the memory, wherein the processor implements the steps of the method for developing a soft structure component intersection line of an airship based on CATIA when executing the computer program.

[0026] A computer readable storage medium, wherein the readable storage medium stores a computer program; the computer program is executed by a processor to implement the steps of the method for developing a soft structure component intersection line of an airship based on CATIA.

[0027] Compared with the prior art, the method has the following technical features:

[0028] The method improves the efficiency and intuitiveness of the soft structure component intersection line of the airship, and makes up for the shortcomings of the airship soft airbag cutting piece that cannot be generated by the traditional axial arc length integral method, and is suitable for the intersection line cutting piece design of each component of the airship. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a structural schematic diagram of a typical cutting piece of an airbag;

[0030] Figure 2 It is a schematic diagram of the intersection line of each component of the airship;

[0031] Figure 3 It is a schematic diagram of the cutting piece calculation principle;

[0032] Figure 4 It is a coordinate schematic diagram of an arbitrary point on the intersection line;

[0033] Figure 5 It is a schematic diagram of the expansion of the feature point on the intersection line; Figure 5 Fig. a in the figure is a schematic diagram of the feature point on the airbag and the auxiliary airbag, and fig. b is a local enlarged schematic diagram of the expansion position of the feature point;

[0034] Figure 6 It is a schematic diagram of macro running result;

[0035] Figure 7The schematic diagram of the intersection lines of the airship components;

[0036] Figure 8 The schematic diagram of the intersection lines of the airbag and the auxiliary airbag in the embodiment;

[0037] Figure 9 The three-dimensional slicing diagram of the soft airbag of the airship;

[0038] Figure 10 The intersection line development diagram;

[0039] Figure 11 The intersection line development result diagram in the embodiment;

[0040] Figure 12 The cutting piece intersection line diagram of the soft airbag of the airship;

[0041] Figure 13 The schematic diagram of the airship finally produced by using the method of the present application. DETAILED DESCRIPTION

[0042] The present application provides a kind of airship soft structure component intersection line development method based on CATIA secondary development, after the plane cutting piece design of airship airbag is completed, the following steps are carried out:

[0043] The component intersection line is composed of many points, and the development value x, y coordinate of a feature point A is drawn by CATIA secondary development macro editing, as shown in Figure 4 The development result of all feature points on the intersection line can be obtained by editing macro and inserting loop statements, and the process is as follows:

[0044] a) Establish the coordinate system in CATIA, and the origin of the coordinate system is at the front end point of the airship airbag, the x-axis is directed to the tail of the airbag along the axial direction of the airbag, the y-axis is directed to the upper side of the airbag perpendicular to the x-axis, and the z-axis is determined by the right-hand rule.

[0045] b) The standard cutting piece of the airship airbag is respectively affined 2, 4, 6, 8…n times in CATIA; all the cutting pieces formed after the affination are joined, as shown in Figure 5 ; wherein; the specific operation of the affination is to keep the x-axis coordinate of the standard cutting piece unchanged, and to expand the y-axis coordinate of the standard cutting piece by 2, 4, 6, 8…n times to form the cutting piece.

[0046] c) Start macro recording;

[0047] d) Take a feature point A on the intersection line of the airbag and the auxiliary airbag at an arbitrary ratio;

[0048] e) Make a plane parallel to the yz plane through A, and make a plane The intersection line of the air bag and the point A is divided into a straight line I, the straight line I is pulled up h1=20mm in the x direction, unfolded in the y direction of the xy plane, and the extreme value in the y direction is taken; a plane is made through A and the x axis , a plane is made through the normal line of the intersection line of the air bag and the point A, the straight line m is pulled up h2=20mm in the normal direction, unfolded in the x direction of the xy plane, and the extreme value in the x direction is taken; the two extreme values are intersected, and the intersection point is A'.

[0049] e) A straight line a is made through A' in the y axis direction to intersect all the joints in step a), the point B closest to A' is taken by approximation, the straight line a is divided at the point B to obtain the straight line BA', the intersection point B' of the straight line BA' and the standard cutting piece is made, and the starting point of the straight line BA' is moved to B' by point-to-point translation, and the end point A'' is the unfolded point of the point A on the final intersection line;

[0050] f) other points, lines and surfaces except the point A'' are hidden;

[0051] g) the macro recording is ended to generate a VBscript script language;

[0052] h) the VBscript script language is added and changed with a loop statement, and the program is run.

[0053] Language="VBSCRIPT"

[0054] Sub CATMain()

[0055] Set partDocument1 = CATIA.ActiveDocument

[0056] Set part1 = partDocument1.Part

[0057] Set hybridBodies1 = part1.HybridBodies

[0058] SethybridBody1=hybridBodies1.ItemSethybridShapes1=hybridBody1.HybridShapes

[0059] Set hybridShapeSplit1 = hybridShapes1.Item

[0060] ​Set reference1 = part1.CreateReferenceFromObject(hybridShapeSplit1)

[0061] Set hybridShapeExtract1 = hybridShapes1.Item

[0062] Set reference2 = part1.CreateReferenceFromObject(hybridShapeExtract1)

[0063] Set hybridShapeFactory1 = part1.HybridShapeFactory

[0064] k=1 / n(1)

[0065] for i=1 to n(2)

[0066] SethybridShapePointOnCurve1= hybridShapeFactory1.AddNewPointOnCurveWithReferenceFromPercent(reference1, reference2, k, False)(3)

[0067] …………

[0068] selection6.Clear

[0069] k=k+1 / n(4)

[0070] next

[0071] End Sub

[0072] The above program, (1), (2), (4) is the added loop statement, (3) k value is the ratio of feature points. N is the number of feature points taken on the intersection line.

[0073] Run this program can be in the CATIA map generated n feature points of the spread point, the running results as Figure 6 shown.

[0074] In practice, the intersection line is distributed in different patches, but in order to facilitate and clear intersection line distribution, macro run after all the spread points are reflected in a patch. With spline curve connecting these points, and with the help of CAD, the intersection line is moved to the corresponding patch, that is, the intersection line of each component can be obtained, as Figure 7As shown.

[0075] Embodiment:

[0076] The airship intersection line is unfolded by using the method of the application, and the results are shown in Figure 8 The three-dimensional slice diagram of the soft airbag of the airship is shown in Figure 9 The intersection line unfolding is shown in Figure 10 The intersection line results are shown in Figure 11

[0077] According to the application, the CATIA secondary development method is adopted, the VBscript script language in the drawing process is obtained through macro recording, and corresponding modification is made as follows.

[0078] Language="VBSCRIPT"

[0079] Sub CATMain()

[0080] Set partDocument1 = CATIA.ActiveDocument

[0081] Set part1 = partDocument1.Part

[0082] Set hybridBodies1 = part1.HybridBodies

[0083] SethybridBody1=hybridBodies1.ItemSethybridShapes1=hybridBody1.HybridShapes

[0084] Set hybridShapeSplit1 = hybridShapes1.Item

[0085] Set reference1 = part1.CreateReferenceFromObject(hybridShapeSplit1)

[0086] Set hybridShapeExtract1 = hybridShapes1.Item

[0087] Set reference2 = part1.CreateReferenceFromObject(hybridShapeExtract1)

[0088] ​Set hybridShapeFactory1 = part1.HybridShapeFactory

[0089] k = 1 / n

[0090] for i = 1 to n

[0091] Set hybridShapePointOnCurve1 = hybridShapeFactory1.AddNewPointOnCurveWithReferenceFromPercent (reference1, reference2, k, False)

[0092] …

[0093] selection6.Clear

[0094] k = k + 1 / n

[0095] next

[0096] End Sub

[0097] Using the above program, the cutting piece intersection line is generated, and the cutting piece intersection line of the airship gas bag and the auxiliary gas bag is shown in Figure 12 , and the produced airship soft gas bag is shown in Figure 13 .

[0098] The above examples are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can be modified, or some technical features can be replaced by equivalent ones; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A method for airship soft structure component intersection line unfolding based on CATIA secondary development, characterized in that, After the flat panel design of the airbag is completed, the following steps are performed: Establish a coordinate system in CATIA; In CATIA, the standard cut pieces of the airship airbag are affined 2, 4, 6, 8...n times respectively; and all the cut pieces formed after affine mapping are joined together. Take a feature point A at any ratio on the intersection line of the airbag and the auxiliary airbag; Make a plane through feature point A Parallel to the yz plane, get the plane The intersection with the airbag, using feature point A to truncate the intersection line, you can get the curve l, curve l with x direction to pull up h1, unfolded in the y direction of the xy plane, take the maximum value of y direction; through the feature point A and x axis to make a plane , get the plane The intersection with the airbag, using feature point A to truncate the intersection line, you can get the curve m, through the feature point A to make a plane The normal line of the plane, curve m with the normal direction to pull up h2, unfolded in the x direction of the xy plane, take the maximum value of x direction; the intersection of the two maximum values, the intersection point is A' Draw a straight line a along the y-axis from A'. Line a intersects with the joints of all the cut pieces formed after affine transformation, generating multiple intersection points. Select the point closest to A' from these intersection points and set it as point B. Divide line a at point B to obtain line BA'. Draw the intersection point B' of line BA' with the standard cut piece. Move the starting point of line BA' to B' through point-to-point translation. Its endpoint A'' is the unfolded point of feature point A on the final intersection line. Connect the unfolded points of all feature points with spline curves, and then move the intersection line to the corresponding pattern piece to obtain the intersection line of each component.

2. The method of claim 1, wherein, The origin of the coordinate system is at the front end of the airship's airbag. The x-axis points along the axial direction of the airbag towards the tail of the airbag, the y-axis is perpendicular to the x-axis and points upwards from the airbag, and the z-axis is determined by the right-hand rule.

3. The method of claim 1, wherein, The method also includes hiding all points, lines, and surfaces except for point A''.

4. The method for unfolding the intersection lines of airship soft structure components based on CATIA secondary development according to claim 1, characterized in that, The specific operation of the affine is as follows: keep the x-axis coordinate of the standard pattern piece unchanged, and enlarge its y-axis coordinate by multiples of 2, 4, 6, 8...n to form the pattern piece.

5. The method for unfolding the intersection lines of airship soft structure components based on CATIA secondary development according to claim 1, characterized in that, The values ​​are h1=20mm and h2=20mm.

6. The method for unfolding the intersection lines of airship soft structure components based on CATIA secondary development according to claim 1, characterized in that, Using CATIA's secondary development macro editing, you only need to use CATIA to draw the expanded x and y coordinates of a feature point A, and then edit the macro to insert a loop statement to obtain the expanded results of all feature points on the intersection line.

7. The method for unfolding the intersection lines of airship soft structure components based on CATIA secondary development according to claim 3, characterized in that, Before taking a feature point A at any ratio on the intersection line of the airbag and the auxiliary airbag, the method further includes: starting macro recording; After hiding all points, lines, and surfaces except point A'', the process also includes: End macro recording to generate VBScript script language; Add and modify loop statements in the VBScript scripting language, set the ratio of feature points and the number of feature points taken on the intersection line, and run the program.

8. A terminal device, comprising a processor, a memory, and a computer program stored in the memory, characterized in that, When the processor executes the computer program, it implements the steps of the airship soft structure component intersection line unfolding method based on CATIA secondary development as described in any one of claims 1-7.

9. A computer-readable storage medium, characterized in that, The readable storage medium stores a computer program; when the computer program is executed by a processor, it implements the steps of the airship soft structure component intersection line unfolding method based on CATIA secondary development according to any one of claims 1-7.

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