JP3115291B2 - A method for developing a curved surface of a three-dimensional plate into a plane and a computer system used therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for developing a curved surface of a three-dimensional plate into a plane, and a computer system used for the method.

[0002]

2. Description of the Related Art In the recent automobile industry, a three-dimensional glass plate is increasingly used as a front glass or a rear glass because of its need for a wide field of view from a driver together with its novel design.

For example, in the prototype stage of a car, a designer first draws a sketch of a new car, creates a somewhat accurate drawing based on the sketch, converts the contents of the drawing into digital values by a digitizer, and converts the drawing into CAD. Captured by the device. The CAD system monitors the three-dimensional shape of the prototype car using the attached high-definition CRT,
Modify the body shape to determine the optimal body shape.
This optimal body shape is prototyped with clay or the like, and then the subtle changes in appearance are further corrected to determine the final three-dimensional shape of the mass-produced vehicle.

[0004] Of course, the drawings are revised by the CAD device with each modification, and the digital values are stored in the CAD device and saved on magnetic tape. The drawing is output as a formal drawing by an XY plotter having a high resolution of 0.1 mm, for example.

For example, in the process of manufacturing a three-dimensionally shaped windshield, only a portion of the windshield is extracted from a vehicle body prototyped with clay or the like, and furthermore, for economic reasons or for shortening the startup period from trial production to mass production. For this reason, a ring-shaped wooden mold having a three-dimensional surface (curved surface) obtained by copying only the peripheral region of the windshield and having an open central portion is formed. This wooden mold is used not only for forming a mold but also for inspection after molding.

In order to manufacture a windshield for a mass-produced vehicle, it is essential to use a two-dimensional glass plate having a dimension obtained by developing a three-dimensional windshield as a substrate. The two-dimensional glass plate is formed into a three-dimensional windshield by a forming device.

Heretofore, in order to obtain a two-dimensional developed shape of a three-dimensional glass plate, an operator hits paper on a ring-shaped wooden mold having a three-dimensional surface and makes a copy. Since this wooden mold has a ring shape, a three-dimensional shape corresponding to the center of the glass plate is not formed. Therefore, the worker
The two-dimensional paper must be pressed against a wooden mold, keeping in mind the central bulge.

[0008]

It is difficult for an operator to press two-dimensional paper against a wooden mold while keeping in mind the central bulge. In addition, this manual two-dimensional expansion method of a paper pad has a problem that the two-dimensional paper is forcibly applied to a three-dimensional wooden mold and copied, and thus the dimensional accuracy is poor, that is, there are many errors. In addition, a three-dimensional glass plate manufactured using a glass plate developed by this method may be in a state of being undersized or oversized, and may not fit into a predetermined frame of a car. If the dimensions are not enough, the width of the bonding area with the car body becomes narrow,
There is a fear that a predetermined strength cannot be obtained.

[0009] Furthermore, the copying work by hand takes time, and the two-dimensional development work that takes much time cannot be used as input data for the automatic control process. Therefore, there is also a problem that the input data for obtaining the three-dimensional wooden shape must be input again to the computer system for automatic control.

In view of the above problems, the present invention provides a method of two-dimensionally developing a curved surface of a plate material such as a three-dimensional glass plate using a computer system (hereinafter referred to as a “two-dimensional expansion method”). And a computer system used for the same.

[0011]

SUMMARY OF THE INVENTION Accordingly, the present invention provides
A method of developing a curved surface of a three-dimensional plate into a plane using a computer system, comprising the steps of: (a) inputting shape data of the three-dimensional plate by digitizing it from a design drawing with a digitizer, or three-dimensional plate Inputting the shape data of the curved surface from the magnetic recording device and storing it in the memory of the computer system ; (b) reading the shape data from the memory,
In operation of the computer system, determining the expansion center point To either on the surface of the plate of three-dimensional shape which is the input, (c) in the calculating portion of the computer system, a point in the curved surface and deployment center point To A step of obtaining an XZ plane and a YZ plane which are respectively orthogonal to the contacting plane and which are orthogonal to each other; (d) a step of determining an n-th set point Tn on the shape line of the curved surface by an arithmetic unit of the computer system ( Where n
1,2,3, is an integer of ~), (e) in the calculating portion of the computer system, each parallel XZn surface and YZn surface with the XZ plane and YZ plane with through said each n-th set point Tn (F) calculating the XZ by the arithmetic unit of the computer system;
(g) a step of obtaining an intersection at which an intersection line between the n-th surface and the curved surface intersects the YZ surface and obtaining a length Ln on the curved surface between the intersection and the n-th set point Tn ; In the arithmetic unit of the computer system, the YZ
(h) determining a crossing point at which an intersection line between the n-th surface and the curved surface intersects the XZ surface and obtaining a length Mn on the curved surface between the intersection and the n-th set point Tn ; The lengths Ln and Mn are plotted on a two-dimensional coordinate by an arithmetic unit of the computer system, and
A step of determining an expansion point Dn; (i) an arithmetic unit of the computer system, wherein n = 1,
Steps (d) to (h) are repeated for 2, 3, to determine a plurality of development points Dn, respectively, thereby obtaining a curve An corresponding to the shape line. (J) The computer system In the calculation section, the above curve
Determining a two-dimensional developed shape of the curved surface of the three-dimensional plate material based on An , and storing the determined two-dimensional developed shape in the memory ; and (k) outputting the determined two-dimensional developed shape from the memory to a plane. This is a method of developing a curved surface of a three-dimensionally shaped plate material into a flat surface.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 schematically show a method of developing a three-dimensionally curved plate two-dimensionally. For example, when an automaker is producing a clay model of a prototype vehicle (clay model), the three-dimensional shape data Px, y, and z of each part of the model are sequentially stored in CA.
The image is input to the D device, the shape of which is displayed by a high-definition color CRT, and output as a three-view diagram or a three-dimensional diagram by an XY plotter. The three-dimensional shape data is saved on a magnetic tape.

Accordingly, the manufacturer of the curved plate (in this case, the windshield) 1 extracts a portion corresponding to the windshield 1 of the three-dimensional shape data in the magnetic tape created by the automobile manufacturer, and carries out its CAD. It can be used for a device, which is convenient only to save the trouble of inputting data. Of course, it is possible to read a portion corresponding to the windshield from the three views by a digitizer and input the read portion to the CAD device.

First, a CAD which is a computer system
A three-dimensional curved surface 2 corresponding to the windshield 1 is displayed on the high-definition color CRT of the apparatus. Steps 10 to 23 of developing the three-dimensional curved surface 2 into a two-dimensional shape using a CAD device will be described below.

Step 10: As shown in FIG. 1, one of the curved surfaces 2
The point is defined as the development center point To. This deployment center point To
When the curved surface 2 is bilaterally symmetric as shown in FIGS. 3 and 4, a straight line d that passes through the curve a on the curved surface 2 that is line-symmetric and further connects the upper and lower ends b and c of the curve a It has a tangent e that is parallel.

When the development center point To is set as described above, the tangent e of the curved surface 2 from the upper end b to the development center point To is obtained.
Is always the same direction, and the inclination direction with respect to the tangent line e from the development center point To to the lower end c is always the same direction, so that the two-dimensional expansion calculation by the computer is simplified. Further, in the case of a side glass or the like having an asymmetric three-dimensional shape, the development center point To is set at substantially the center of the upper, lower, left, and right sides according to an empirical rule.

Step 11: An XZ plane P1 extending in the horizontal direction through the development center point To and a YZ plane P2 extending in the vertical direction through the development center point To are determined. These XZ plane and YZ plane function as reference planes.

In this case, the development center point To is defined as Pxo,
defined as yo and zo. In addition, a first line including the line symmetry curve a and orthogonal to the curved surface 2 at the development center point To
The plane is defined as the YZ plane P2. In addition, this song line a
A second plane that includes the upper and lower ends b and c and is orthogonal to the YZ plane P2 is defined as an XY plane. Since the second plane is inclined approximately 30 degrees with respect to the horizontal plane f in the case of the windshield 1 shown in FIGS. 3 and 4, the second plane is rotated together with the curved surface 2 by approximately 30 degrees with respect to the horizontal plane f. Thus, the second plane is made substantially coincident with the horizontal plane f.

This calculation can be easily performed by a CAD device. Furthermore, a third plane passing through the deployment center point and orthogonal to the first plane (YZ plane P2) and the second plane, respectively.
The plane is defined as the XZ plane P1. The leveling by rotation may be performed before setting the development center point To when the curved surface 2 is particularly symmetric.

Step 12: An intersection line S1, which intersects the curved surface 2 with the XZ plane P1 and the YZ plane P2 passing through the development center point To,
Create S2. Therefore, the intersection line S2 coincides with the line symmetric curve a on the curved surface 2 when the curved surface 2 to be developed two-dimensionally is symmetric.

Step 13: Next, the CAD data corresponding to the windshield 1 includes a shape line of the windshield 1 (an outline of the windshield 1, a heater wire printed on the windshield 1, an antenna wire, or a vehicle body). (A boundary line of an area to which an opaque ceramic color is applied, which functions as a blindfold for a bonding portion with the substrate). Therefore, a curve So corresponding to, for example, the inner edge of the ceramic color application region is displayed on the curved surface 2.

Step 14: Specify the n-th set point Tn on these curves So, that is, Pxn, yn, zn. Where n
Is an integer from 1, 2, 3, to... FIG. 1 shows Tn when n = 1.

Step 15: As in Step 11, the XZn plane extending in the horizontal direction through the n-th set point Tn and the YZn plane extending in the vertical direction through the n-th set point Tn are determined. However, the XZn plane and the YZn plane are the reference XZ plane P
1 and the YZ plane P2. In FIG. 1, n = 1
XZ1 plane P3 and YZ1 passing through the n-th set point Tn in the case of
The plane P4 is shown.

Step 16: As in Step 12, intersection lines S (2n + 1) and S (2n + 2) at which the XZn plane and the YZn plane intersect the curved surface 2 at the n-th set point Tn are created. In the case of the first set point T1, as shown in FIG. 1, intersection lines S3 and S4 are created.

Step 17: An intersection Tn2 where the intersection line S2 and the intersection line S3 intersect is determined, and the intersection Tn2 and the n-th set point T
The length Ln on the curved surface 2 between n and n is determined. This length Ln
Is calculated by a subroutine (program) in the CAD apparatus.

The procedure of the subroutine for obtaining the length Ln will be described below. Here, n is 1, 2, 3, or.
First, an intersection between the intersection line S2 and the intersection line S3 is obtained. These S
2 and S3,

(Equation 1) Defined as

(Equation 2) Becomes The intersection point is obtained by mathematically finding a solution of the two unknowns t and u by a method such as the Newton-Raphson method relating to the simultaneous equations. The obtained intersection is defined as T12 (generally, Tn2).

Next, a curve Ln on the curved surface 2 between the intersection Tn2 of the intersection line S2 and the intersection line S (2n + 1) and the n-th set point Tn is determined. The curve Ln has a small length code (chor
d), the code vector when the parameter changes by Δt is approximately

(Equation 3) The length of this curve Ln when the value of the parameter Δt goes from one end to to the other end tn of the curve Ln is

(Equation 4) Can be calculated by The length of the curve Ln can be obtained by obtaining the solution of this equation by a method such as Gauss' quadrature.

In the CAD apparatus, a screen displaying the three-dimensional shape of the windshield 1 (see FIG. 1).
Is a screen of XY coordinates (coordinates of orthogonal axes) (see FIG. 2)
Can be replaced with the display. The deployment center point To is
This corresponds to the origin Do of the two-dimensional coordinates (XY coordinates).

Step 18: An intersection Tn3 where the intersection line S1 and the intersection line S4 intersect is determined, and the intersection Tn3 and the n-th set point T
Then, a length Mn on the curved surface 2 between n and n is determined. This length Mn
Can be executed by a subroutine (program) in the CAD apparatus, as in the case of step 17, and can be displayed on the XY coordinate screen. The calculation procedure for obtaining Mn is the same as the calculation procedure of step 17, except that Ln is Mn, S3 is S4, S2 is S1,
This can be done by reading Tn2 into Tn3.

Step 19: The development point Dn represented by Xn = Ln and Yn = Mn is plotted on the XY coordinates, and the development point Dn is stored. Therefore, the three-dimensional set point Tn corresponds to the two-dimensionally developed point Dn.

Step 20: The above steps 14 to 19 performed for n = 1 are repeated for n = 2, 3, to.

Step 21: Among the curves An passing through the two-dimensional development point Dn of n = 1, 2, 3,. This curve A1 corresponds to one of the boundaries of, for example, a ceramic color application area on the three-dimensional shape windshield 1.
This corresponds to a two-dimensional expansion of a book curve.

Step 22: Steps 13 to 21 are represented by curves A2 and A
Repeat as many times as 3 to. In the case of a symmetrical windshield, for example, the upper half, the right half, and the lower half of the inner edge of the ceramic color (the boundary line along the outer edge of the outer edge of the windshield, for example, 2 cm inside).
Repeat for book.

Step 23: These curves A1, A2, A
The data of 3 to are plotted on an XY plotter.

The sampling interval of the set point Tn depends on the radius of curvature of the curved surface 2. That is, in the case of the windshield 1, sampling is normally performed at a pitch of 50 mm, but when the radius of curvature is large, sampling is performed at a pitch of 100 mm. Conversely, if the radius of curvature is small,
Sampling can be performed at a pitch smaller than the 50 mm pitch.

FIG. 5 shows a configuration of a CAD apparatus for developing a three-dimensional shape into a two-dimensional shape in the present invention.
In this figure, the shape data of the windshield 1 can be input by digitizing the design drawing 7 with a digitizer 8. Alternatively, shape data can be input by, for example, applying a magnetic tape on which the design data is written to a magnetic tape device 9. Also, a floppy disk can be used instead of a magnetic tape.

The input shape data is stored in the computer 10.
The computer 10 sequentially performs a two-dimensional expansion calculation of a three-dimensional curved surface model corresponding to the shape data of the windshield 1. The progress of the calculation and the result are monitored by a graphic display, that is, a high-definition color CRT 11, and numerical data is output by a printer 12, or a display screen of the color CRT 11 is output by a hard copy device 13. The color cathode ray tube 11 and the printer 12
Is provided as confirmation means for the above calculation.

The final result of the two-dimensional development of the three-dimensional curved surface 2 is output by the XY plotter 14 with high resolution. On the basis of the two-dimensional shape, a large number of glass plates having a predetermined shape (outer line, heater line, antenna line, inner edge of the ceramic color application area, etc.) are manufactured, and then the glass plate is formed by a molding apparatus. By being bent into a three-dimensional shape, the windshield 1
Is manufactured. The size and the degree of curvature of the windshield 1 are inspected by placing the windshield 1 on a wooden mold.

In FIG. 5, when CAD data is obtained from the design drawing 7, a number of points Q1, Q on the front view and side view of the curved surface 2 called a Mylar diagram as shown in FIG.
2, Q3,... Are designated by the digitizer 8 to take in three-dimensional coordinates. Next, a geometric three-dimensional shape model of the curved surface 2 is created in the computer 10 operating as a CAD system. That is, first, a lattice-like three-dimensional spline curve passing through a sequence of points taken in by the digitizer 8 is generated, and then the surface is divided into quadrilateral patches (surface elements) with the spline curve as a boundary, and along each side of the patch A bicubic parametric surface such as a Coons surface represented by parameters u and v is created.

In a similar manner, a three-dimensional spline curve such as an outline of a glass plate is also generated. Note that a patch of a curved surface can be represented by a Bezier surface, a B-spline curved surface, or the like. When the shape of the curved surface 2 is designed by a CAD system, a three-dimensional model can be obtained from a magnetic tape or the like on which the design data is written.

FIG. 7 is a schematic flowchart of the two-dimensional expansion method shown in FIGS. In FIG. 7, steps 10 to 23 are schematically shown as S10 to S23, respectively.

In this embodiment, for example, a two-dimensional expansion method used for manufacturing a windshield has been described, but the present invention can be applied to manufacturing a rear glass or a roof glass. In addition, the present invention can be applied to manufacture a three-dimensional curved plate from a two-dimensional plate material such as a hard metal plate having no ductility and being difficult to process, or a plastic plate. Further, as shown in FIG. 2, the case where the set point Tn is developed on the orthogonal axis coordinates (XY coordinates) has been described, but it may be developed on the polar coordinates.

[0043]

As described above, the present invention relates to a method for developing a curved surface of a three-dimensional plate material into a flat surface, wherein the development point Dn of the n-th set point Tn from the development center point To is set in two orthogonal directions. Is determined from the lengths Ln and Mn, so that there is an advantage that the expansion can be performed with high accuracy, that is, with little error.

In addition, since the calculation is performed by the computer, labor can be saved and time is not required. Further, since the numerical data of the two-dimensionally expanded plate material is stored in the computer, it can be used as data of a subsequent process.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a curved surface schematically showing a two-dimensional expansion method of the present invention.

FIG. 2 is an XY coordinate development diagram at a set point of the curved surface in FIG. 1;

FIG. 3 is a plan view of a right half of a windshield to which the two-dimensional expansion method of the present invention is applied.

FIG. 4 is a side view of the windshield of FIG. 3;

FIG. 5 is a schematic block diagram of a CAD apparatus used in the two-dimensional expansion method of the present invention.

FIG. 6 is a diagram showing the CAD apparatus shown in FIG.
It is the front view and side view of the curved surface 2 when obtaining AD data.

FIG. 7 is a schematic flowchart of the two-dimensional expansion method of the present invention shown in FIGS. 1 and 2;

[Explanation of symbols]

 2 Curved surface To expansion center point Tn n-th set point Dn n-th expansion point A curve

Claims (4)

(57) [Claims] 1. A method of developing a curved surface of a three-dimensional plate material into a plane using a computer system, comprising the steps of: (a) inputting shape data of the three-dimensional plate material by digitizing the design data from a design drawing with a digitizer; or A step of inputting the shape data of the curved surface of the three-dimensional plate material from the magnetic recording device and storing it in the memory of the computer system ; (b) reading the shape data from the memory,
In operation of the computer system, determining the expansion center point To either on the surface of the plate of three-dimensional shape which is the input, (c) in the calculating portion of the computer system, a point in the curved surface and deployment center point To obtaining a XZ plane and YZ plane respectively orthogonal and orthogonal to the plane of contact, (d) in the calculating portion of the computer system, determining the n-th set point Tn shape line of the curved surface ( Where n
1,2,3, is an integer of ~), (e) in the calculating portion of the computer system, each parallel XZn surface and YZn surface with the XZ plane and YZ plane with through said each n-th set point Tn (F) calculating the XZ by the arithmetic unit of the computer system;
(g) a step of obtaining an intersection at which an intersection line between the n-th surface and the curved surface intersects the YZ surface and obtaining a length Ln on the curved surface between the intersection and the n-th set point Tn ; In the arithmetic unit of the computer system, the YZ
(h) determining a crossing point at which an intersection line between the n-th surface and the curved surface intersects the XZ surface and obtaining a length Mn on the curved surface between the intersection and the n-th set point Tn ; The lengths Ln and Mn are plotted on a two-dimensional coordinate by an arithmetic unit of the computer system, and
A step of determining an expansion point Dn; (i) an arithmetic unit of the computer system, wherein n = 1,
Steps (d) to (h) are repeated for 2, 3, to determine a plurality of development points Dn, respectively, thereby obtaining a curve An corresponding to the shape line. (J) The computer system In the calculation section, the above curve
Determining a two-dimensional expanded shape of the curved surface of the three-dimensional plate material based on An , and storing the determined two-dimensional expanded shape in the memory ; and (k) outputting the determined two-dimensional expanded shape from the memory to a plane. A method of developing a curved surface of a three-dimensional plate material into a flat surface, characterized by comprising: 2. The method according to claim 1, wherein the plane is a main plane of a glass plate. Wherein said plate member is a glass for automobiles, the three-dimensional shape outline of the rear glass, heater wire, three-dimensional according to claim 1 or 2 which is the inner edge of the antenna line or ceramic color application region A method of developing a curved surface of a shaped plate into a flat surface. 4. A computer system for developing a curved surface of a three-dimensional plate material into a plane, comprising: (a) digitizing shape data of the three-dimensional plate material with a digitizer from a design drawing to input means or three-dimensional shape data; means for inputting a curved shape data sheet from the magnetic recording apparatus, (b) means for determining the expansion center point to either on the surface of the plate of the input three-dimensional shape, (c) and expand the central point the curved surface Means for obtaining an XZ plane and a YZ plane which are orthogonal to each other and which are orthogonal to a plane which is in point contact with To; (d) means for determining an n-th set point Tn on the shape line of the curved surface (where n is 1 (E) means for obtaining an XZn plane and a YZn plane that pass through each of the n-th set points Tn and are respectively parallel to the XZ plane and the YZ plane. (F) The XZn The intersection of the surface and the curved surface is the Y
Means for finding an intersection that intersects with the Z plane and finding a length Ln on the curved surface between the intersection and the n-th set point Tn; (g) an intersection line between the YZn plane and the curved surface is X
Means for finding an intersection that intersects the Z-plane and finding a length Mn on the curved surface between this intersection and the n-th set point Tn; (h) expressing these lengths Ln and Mn on two-dimensional coordinates Means for plotting to determine the n-th development point Dn; (i) above (d) to (h) for n = 1, 2, 3,
Means for determining a curve An according to the shape line by repeating the process and determining a plurality of development points Dn, respectively, (j) two-dimensional development of a curved surface of a three-dimensionally shaped plate material based on the curve An A computer system for developing a curved surface of a three-dimensionally shaped plate material, comprising: means for determining a shape; and (k) means for outputting the determined two-dimensionally developed shape to a plane.