JP3307103B2 - Teaching method of shape measurement procedure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a teaching method for teaching a shape measuring procedure of a shape of an object to a shape measuring apparatus using a numerical model representing the assumed shape of the object in three dimensions in detail. In particular, the present invention relates to a teaching method that enables automatic removal of a measurement point from an unprocessed unprocessed portion.

[0002]

2. Description of the Related Art When teaching a measuring procedure of a shape of an object to be measured to a shape measuring device, if the object is designed by computer-aided design (CAD), the object is obtained in a designing process by the CAD. In addition, when teaching is performed using a numerical model that three-dimensionally details a design shape that is an assumed shape of an object by coordinate values of a point group of intersections (grid points) of a grid-like reference line, the time required for teaching is reduced. The teaching method using such a numerical model has the advantages that it can be largely omitted, and that it is possible to easily compare the measurement result with the design shape and to easily grasp the shape error of the actual object. Conventionally, for example, the applicant of the present application
-12511.

In the conventional method shown in the flow chart on the left side of FIG. 8 applied to, for example, the shape measurement of a body panel molding die, a relatively high-performance host having CAD and CAM (computer-assisted processing) functions is used. It has a computer, a normal three-dimensional measuring device as a shape measuring device, and several terminal devices 1 for transmitting and receiving data to and from the host computer and controlling the three-dimensional measuring device and processing measured data. A measurement system including a minicomputer to be used is used, and a user of the measurement system first
As shown in (a), a numerical model indicating a design shape which is an assumed shape of the mold sent from a host computer is displayed on a screen by a terminal device 1 of the minicomputer, and it is desired to measure from the shape of the numerical model. Select a section.

[0004] Next, in this method, the above-mentioned user is required to operate as shown in FIG.
As shown in (b), the design section of the mold at the selected section is displayed on the screen of the minicomputer on the screen, and the operation of the mouse 2 and the keyboard 3 of the minicomputer is used to specify the measurement range, and The measurement conditions (tolerance value and MAX-DP value) are set, and then the designated measurement range and the set measurement conditions are sent from the minicomputer to the host computer as shown in FIG. A computer is caused to perform a measurement point extraction process of extracting measurement points within the measurement range from reference data representing the selected design cross-sectional shape of the numerical model as a point sequence based on the measurement conditions.

This measurement point extraction processing is specifically performed according to the procedure shown in FIG. 9. First, in step 11, the first point on the reference data within the measurement range is set as a measurement point.
In the following step 12, the first point is set as a comparison start point, a point one point ahead of the comparison start point is set as a study point, and a point one point ahead of the study point is set as a target point, and in the next step 13, In the tolerance / separation distance determination, first, as shown in FIG. 10A, the comparison start point on the reference data is point A, the examination point is point B, and the target point is point B, as shown in FIG. C, and as shown in FIG.
A distance d between a line segment AC connecting the two points A and C with a straight line and the examination point B is checked, and the distance d is equal to or larger than the tolerance value (d
Tolerance determination is performed to determine whether or not ≧ tolerance value. As a result, if the distance d is equal to or greater than the tolerance value, the examination point B is adopted. On the other hand, when the examination point B is not adopted as a result of the tolerance determination, the length L of the line segment AC is equal to or greater than the MAX-DP value (maximum separation distance) (L ≧ MAX-DP value). A separation distance determination is performed to determine whether or not the length L is equal to or greater than the MAX-DP value.

In the next step 14, it is determined whether or not the above considerations have been adopted.
In 15, the examination point is set as a measurement point, and in the following step 16, it is determined whether the target point is the last point on the reference data in the measurement range, and if the target point is not the last point In step 17, the above examination point is set as a new comparison start point, the point ahead of the comparison start point is considered as the examination point, and the point ahead of the examination point is set as the target point, and Return to 13. On the other hand, if the above-mentioned examination point is not adopted in the above-mentioned step 14, in step 18, similarly to step 16, it is determined whether or not the target point is the last point on the above-mentioned reference data in the above-mentioned measurement range. If it is determined that the target point is not the last point, in step 19, a point one point ahead of the target point is set as a new target point, and the one point ahead is set as a new examination point, and Return to step 13. If the target point at that time is the last point in step 16 or step 18, the last point is set as a measurement point in step 20, and the measurement point extraction process ends. According to such measurement point extraction processing, by the tolerance determination, it is possible to thin out the measurement points of the portion where the degree of undulation is smaller than the tolerance value, and to determine the distance between the measurement points exceeding the maximum separation distance by the separation distance determination. Can be prevented from being too far apart.

[0007] By the way, in general, when a die is machined by CAM, a tip of a ball end mill or the like defines a hemispherical surface during machining so that surfaces in various directions can be machined in a fixed machining axis direction. As shown in FIG. 11, a concave portion having a design cross-sectional shape such as an L-shape or a V-shape which is a broken shape such as an L-shape or a V-shape as shown in FIG. Even with No. 5, processing cannot be performed as designed.
Therefore, in the case where the angle between both side surfaces is not so large, the corner of such a concave portion of the mold 4 as the object is
There is an unprocessed portion R in which the unprocessed amount, that is, the distance between the position of the break point in the design cross-sectional shape and the actual processed surface exceeds the measurement tolerance, and the unprocessed portion R exceeds the measurement tolerance. Since there is no need to perform measurement because it is clear that there is an error, as shown in FIG. 12, a point sequence of the reference data representing the cross-sectional shape of the mold 4 or a point sequence of the measurement points extracted therefrom. The portion corresponding to the unprocessed portion R at the corner of the concave portion of the broken portion, that is, the corner portion (may be convex or concave), becomes a measurement unnecessary portion, and its measurement is performed. The point Px at the unnecessary portion is a measurement unnecessary point.

Therefore, in this conventional method, after extracting a sequence of measurement points from a sequence of points of reference data as described above, FIG.
As shown in FIG. 8D, the user of the measurement system causes the mini computer to display a screen of the extracted measurement point sequence on the terminal device 1, and then, as shown in FIG.
Although the measurement unnecessary point Px in the above measurement unnecessary part is deleted to shorten the time required for measurement, is the measurement unnecessary part corresponding to the unprocessed part R where an error exceeding the measurement tolerance occurs? To be precise, the determination of the presence or absence of the concave portion is made through two contact points of both sides of the spatially extending concave portion having the design shape as described above and a hemispherical surface having a radius equal to the radius of the minimum diameter tool. In the cross section orthogonal to the extending direction, the distance between the arc that is the cross section of the hemispherical surface and the intersection of the two cross sectional lines that are the cross sections of both sides is checked, and the distance exceeds the measurement tolerance. However, the cross section for obtaining the reference data in the teaching method described above is not necessarily a cross section orthogonal to the extending direction of the concave portion.

That is, the cross section for obtaining the reference data is a vertical cross section orthogonal to the side surface of the mold as viewed from above as shown in FIG. 8 (a), while the recess is formed in the horizontal direction along the side surface of the mold. In such a case, the cross section for obtaining the reference data is orthogonal to the extending direction of the concave portion, but the cross section for obtaining the reference data is not orthogonal to the mold side surface or the concave portion is inclined along the slope. When extending, the cross section for obtaining the reference data may not obliquely intersect with the extending direction of the concave portion but obliquely intersect. Even when the distance between the arc and the corner point when the circular arc having the radius equal to the radius of the tool is in contact with the measuring point exceeds the measurement tolerance, the cross section orthogonal to the extending direction of the above-described concave portion, which is an actual error, is obtained. Distance between the arc of a circle and the intersection of the two section lines There may be a case when it does not exceed the measurement tolerance.

Therefore, in this conventional method, the user of the measurement system can use the measurement point sequence displayed on the screen as shown in FIG. From the angle between the point trains, the distance between the arc and the corner point when an arc having a radius equal to the radius of the tool having the minimum diameter is brought into contact with the corner portion is estimated, and the reference data is obtained from the distance. Considering at what angle the obtained cross section intersects with the extension direction of the concave portion corresponding to the corner in the original three-dimensional numerical data, the error at the corner of the corner is calculated. Visually judge whether or not the measurement tolerance will be exceeded.If the measurement tolerance is likely to be exceeded, the corner of the corner is regarded as a measurement unnecessary part, and the corner of such a corner and the nearest corner To the point the measurement unnecessary points Px, their measurement unnecessary points Px, are removed by one point at a time hit (designated) by the operation of the mouse 2 above minicomputer.

In the conventional teaching method, the above procedure is repeated for the section to be measured of the mold, and the measuring points are taught to the minicomputer for all of the sections to be measured. Is taught to the minicomputer so that the probe of the sensor of the three-dimensional measuring device sequentially follows the measurement point sequence.
The measurement operation is performed by controlling the operation of the dimension measuring device, and the data obtained by the measurement is appropriately processed by the minicomputer so that a user of the system can easily view the data, and is displayed on the screen by the terminal device 1. .

[0012]

SUMMARY OF THE INVENTION The applicant of the present invention has been studying a teaching method using a numerical model representing the assumed shape of an object in three dimensions in detail, and has been working on the last stage of teaching. It has been conceived that if the point where measurement unnecessary points are deleted manually is improved, the man-hour required for teaching can be further reduced. Then, while studying the method, they came to the conclusion that the reference data has, for each point in the sequence of points, the normal vector of the surface of the numerical model at the position corresponding to that point.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and provides a teaching method which is a further improvement of the above-described conventional teaching method. From a numerical model that represents the assumed shape in three dimensions in detail, the cross-sectional shape of the object is represented by a sequence of points, and the normal vector of the surface of the numerical model at a position corresponding to each point in the sequence of points. Create reference data having a reference point, from the point sequence of the reference data, extract points that need to be measured based on a predetermined measurement reference as measurement points, and use the point sequence of the measurement points to a shape measuring device to determine the shape of the object. When teaching the shape measurement procedure, regarding the concave portion such that the error generated by the unprocessed tool with the smallest diameter tool among the tools used for processing the object falls within the measurement tolerance, the both side surfaces of the concave portion are used. Each as a plane In this case, the minimum value of the angle between the both sides is obtained in advance as a reference angle, and at the time of extracting the measurement points, the positions at the positions respectively corresponding to the points before and after the point to be considered in the point sequence of the reference data are extracted. The angle between the surfaces of the numerical model is less than the reference angle,
When the point to be examined and the points before and after it form a concave shape, the point to be examined is not extracted as the measurement point.

In the method of the present invention, when the angles between the surfaces of the numerical model at positions respectively corresponding to points before and after the point to be examined in the point sequence of the reference data are obtained, The value obtained by dividing the inner product of the normal vectors at each of the points before and after the point by the product of the absolute values of the normal vectors with a negative sign is obtained as an angle at which a cosine value is obtained. The angle may be set as the sandwiching angle.

Further, in the method of the present invention, when determining whether or not the point to be examined and points before and after the point form a concave shape, in the cross section in which the reference data is created,
A measurement progress direction vector and a reference vector that is orthogonal to it and point to a certain space are set in advance, and a vector heading from the point before the point to be examined to the point to be examined and the point to be examined from the point to be examined. The cross product of the vector toward the subsequent point and the cross product of the measurement traveling direction vector are obtained and used as a judgment vector, and when the inner product of the judgment vector and the reference vector has a positive sign, It may be determined that the point and points before and after the point form a concave shape.

Further, in the method of the present invention, a circle having a radius equal to the radius of the tool having the minimum diameter in a cross section orthogonal to the surfaces based on an angle between the surfaces of the numerical model. Find the distance from the two points of contact to the intersection of their cross-sectional lines, and in the point sequence of the reference data, a point at a distance less than the calculated distance from the point of interest not extracted as the measurement point. , May not be extracted as the measurement points.

[0017]

According to the method of the present invention, a concave portion in which an error generated by unprocessed tool with the smallest diameter tool among the tools used for processing an object falls within the measurement tolerance is set. The minimum value of the angle between both sides when each side is a plane is determined in advance as a reference angle, and the reference data representing the cross-sectional shape of the object created from the numerical model representing the assumed shape of the object is obtained. When extracting points requiring measurement based on a predetermined measurement standard from a point sequence as measurement points, the surface of the numerical model at positions respectively corresponding to points before and after the point to be considered in the point sequence of the reference data. The sandwiching angle is obtained using the normal vector of the surface of the numerical model at those positions, and the sandwiching angle is less than the reference angle, and the point to be examined and the points before and after it are concave. The shape If it is do not extract the points of the consideration as the measurement point.

That is, according to the method of the present invention, the corners of the concave corners in the point sequence of the reference data which the system user has referred to on the screen in order to determine whether or not the measurement is unnecessary. Instead of finding the angle between the point sequence before and after the point, the surface of the numerical model at the position corresponding to each of the points before and after that forms a concave shape together with the point to be considered in the point sequence of the reference data. The angle, that is, the angle between the two cross-sectional lines that are the respective cross-sections of the both sides in a cross-section orthogonal to the extending direction of the spatially extending recess formed by the surfaces of the numerical models as the both sides And the angle between the surfaces of the numerical model is determined by changing the angle of the concave portion such that the error generated by the unprocessed tool with the smallest diameter tool among the tools used for processing the target object determined in advance falls within the measurement tolerance. ,Each When the angle between the sides of the numerical model is smaller than the reference angle, the points before and after the point to be considered are compared. In this case, the actual error caused by the unprocessed portion does not fall within the measurement tolerance but exceeds the measurement tolerance.

Therefore, the point to be considered is located at a measurement-unnecessary portion corresponding to the unprocessed portion where the error caused by the unprocessed portion using the tool having the minimum diameter exceeds the measurement tolerance.
Therefore, the method of the present invention eliminates the points that need to be considered as measurement unnecessary points without automatically extracting them as measurement points when the measurement points are extracted from the reference data. According to this, when teaching the shape measurement procedure of the object to the shape measuring apparatus using the point sequence of the measurement points, the man-hour for manually deleting unnecessary measurement points at the last stage of the teaching can be greatly reduced. Thus, the number of man-hours required for teaching can be further reduced as compared with the conventional method, and only the unnecessary measurement points can be reliably removed, and the possibility of erroneously deleting the necessary measurement points can be eliminated.

When calculating the angle between the surfaces of the numerical model at positions corresponding to the points before and after the point to be examined in the point sequence of the reference data, respectively, the points before and after the point to be examined are determined. The value obtained by dividing the inner product of the normal vectors by the product of the absolute values of the normal vectors is obtained as an angle at which a value obtained by adding a negative sign becomes a cosine value, and the angle is defined as the above-described angle. Then, the angle between the surfaces of the numerical model at the positions respectively corresponding to the points before and after the point to be examined can be easily and accurately obtained.

When judging whether or not the point to be examined and the points before and after the point form a concave shape, in the section in which the reference data is created, the measurement progress direction vector and the direction in which the space exists And a reference vector pointing to the point to be examined is set in advance, and an outer product of a vector from the point before the point to be examined to the point to be examined and a vector from the point to be examined to the point after the point to be examined, and the above measurement The outer product of the traveling direction vector is obtained and used as a determination vector.If the inner product of the determination vector and the reference vector has a positive sign, the point to be considered and the points before and after it form a concave shape. If the point under consideration and the points before and after it form a concave shape, the determination vector is directed toward a certain space, so that the determination vector and the reference The sign of the inner product of the vector also become positive,
On the other hand, if the point under consideration and the points before and after it do not form a concave shape, the judgment vector is directed to the direction of the entity instead of space or becomes a zero vector, so that the judgment vector and the reference vector Is not positive, it is possible to easily and accurately determine whether the point under consideration and the points before and after it form a concave shape.

Further, based on the angle between the surfaces of the numerical model, two points of contact between a cross-sectional line of the surface and a circle having a radius equal to the radius of the tool having the minimum diameter in a cross section orthogonal to the surfaces are provided. Find the distance to the intersection of those section lines,
In the point sequence of the reference data, a point at a distance less than the obtained distance from the point to be examined that is not extracted as the measurement point, that is, a part to be processed by the tool having the minimum diameter other than the point to be examined. If the points located in the measurement-unnecessary part in the reference data corresponding to are not extracted as the measurement points, when extracting the measurement points from the point sequence of the reference data, not only the points to be examined but also more Can be automatically excluded without extracting points that are unnecessary measurement points as measurement points, and using the point sequence of the measurement points to teach the shape measurement device the shape measurement procedure of the object. In the last stage of the process, the man-hour for manually removing unnecessary measurement points is further reduced,
The number of steps required for teaching can be further reduced.

[0023]

Embodiments of the present invention will be described below in detail with reference to the drawings. The flow on the right side of FIG. 8 shows a teaching procedure of one embodiment of the teaching method of the shape measurement procedure of the present invention applied to, for example, the shape measurement of a body panel molding die. , As in the conventional method,
And a relatively high-capacity host computer having the functions of a CAM and a CAM, an ordinary three-dimensional measuring device as a shape measuring device, and several terminal devices 1 for transmitting and receiving data to and from the host computer. A measurement system including a minicomputer for controlling the three-dimensional measuring device and processing the measurement data is used. First, as shown in FIG. A terminal computer 1 displays a numerical model indicating a design shape that is an assumed shape of a mold on a screen of the terminal device 1, and selects a cross section to be measured from the shape of the numerical model.

Next, in the method of this embodiment, similarly to the conventional method, as shown in FIG. 8B, the user displays on a minicomputer a design cross-sectional shape of the mold at the selected cross-section. Then, by operating the mouse 2 and the keyboard 3 of the minicomputer, the measurement range is specified and the measurement conditions (tolerance value and MAX-DP value) are set. Next, as shown in FIG. Then, the specified measurement range and the set measurement conditions are sent from the minicomputer to the host computer, and the measurement is performed within the measurement range from the reference data representing the selected design cross-sectional shape of the numerical model in a point sequence to the host computer. A measurement point extraction process for extracting points based on the measurement conditions is performed.

The measurement point extraction processing performed by the method of this embodiment is performed in accordance with the procedure shown in FIG. 1. First, in step 21, as shown in FIG. The minimum value θs of the angle between the side surfaces 6 and 7 of the concave portion for the concave portion in which the unprocessed amount of the tool 5 having the minimum diameter r falls within the measurement tolerance ds is defined as the geometrical value between them. From the relationship, it is calculated by the following equation (1).

(1) (ds + r) Sin (θs / 2) = r Therefore, Sin (θs / 2) = r / (ds + r), therefore, θs = 2 Sin ⁻¹ ｛r / (ds + r)｝ (1) That is, as is apparent from FIG.
If the angle between them is the angle θs determined by the above equation,
The distance between the position of the break point F in the design cross-sectional shape DF corresponding to the recess and the actual machined surface is a measurement tolerance ds. If the angle between the side surfaces 6 and 7 is larger than the angle θs, , The distance between the position of the break point F and the actual work surface falls within the measurement tolerance ds.

Next, in step 22, the first point on the reference data within the measurement range is set as a measurement point, and in step 23, the first point is set as a comparison start point.
The point one point ahead of the comparison start point is considered as a point to be considered (point to be considered), and the point one point ahead of the point to be considered is set as a target point. In the next step 24, the step shown in FIG. Perform the tolerance / separation distance determination in the same way as performed in step 13, and thin out the measurement points where the degree of undulation is smaller than the tolerance value, and prevent the measurement points from exceeding the maximum separation distance too much. I do. Then, in the next step 25, it is determined whether or not the above-mentioned study point has been adopted. If it is determined that the study point has been adopted, in step 26, a measurement unnecessary part determination process is performed on the study point.

In the measurement unnecessary part determination process, every time a study point is adopted, the point immediately before the study point on the reference data is set to the point An, the study point is the point Bn, and the study point is set to the point Bn. Assuming that the next point is a point Cn, as shown in FIG. 3, an angle θn between the shape surfaces of the numerical model at each of the points An and Cn before and after the examination point Bn is obtained. In consideration of the fact that the data of each point in the point sequence of the reference data has the data of the normal vector of the shape surface at the position corresponding to that point in the original numerical model from which the point was obtained, the following operation Equation (2)
The normal vectors VAn, V of the shape surface of the numerical model at each of the points An, Cn obtained from the reference data, respectively,
An angle at which a value obtained by dividing the inner product of Cn by the product of the absolute values of their normal vectors and giving a negative sign a cosine value is obtained, and the angle is defined as the above-described angle θn.

(2) Cos (π−θn) = (VAn · VCn) / (| VAn || VCn |) Also, Cosθn = −Cos (π−θn) Therefore, θn = Cos− ¹ ｛− (VAn · VCn) / (| VAn || VCn |)｝ ・ ・ ・ (2)

In this case, as shown in FIG. 4, the angle θn between the shape surfaces of the numerical model obtained above is determined by setting the remaining amount of machining with the tool 5 having the minimum diameter previously obtained in step 21 within the measurement tolerance ds. Compared with the minimum value θs of the angle between both side surfaces 6 and 7 of the concave portion that fits in the range, as shown in FIG.
In the case of θs, the distance dn between the position of the break point F in the design sectional shape DF corresponding to the concave portion having the sandwiching angle θn and the actual processing surface is dn> ds with respect to the measurement tolerance ds. In the vicinity of the points An and Cn before and after the above, the error generated due to the unprocessed portion with the tool having the smallest diameter is a measurement unnecessary portion corresponding to the unprocessed portion exceeding the measurement tolerance.
When the examination point Bn and the preceding and following points An and Cn form a concave shape, it is a measurement unnecessary point candidate that can be the measurement unnecessary point Px.

If the examination point Bn becomes a measurement unnecessary point candidate in the unnecessary measurement part determination processing in step 26, the next step 27
If the determination is made in step (a), the process proceeds to step 28, where irregularity determination is performed to determine whether or not the study point Bn and the preceding and following points An and Cn form a concave shape. In the cross section obtained, a measurement progress direction vector β and a reference vector α that is orthogonal to the space and are set in advance are set in advance, and the following calculation formula (3) is used to set the measurement progress direction vector β before the examination point Bn. An outer product (VAB × VBC) of a vector VAB from the point An to the examination point Bn and a vector VBC from the examination point Bn to the subsequent point Cn, and an outer product (VAB × VBC) × of the measurement progress direction vector β β is determined and used as a determination vector VC. The determination vector VC and the reference vector α
And the inner product (VC · α).

## EQU3 ## VC = (VAB × VBC) × β (3) And if the inner product (VC · α) has a positive sign,
It is determined that the consideration point Bn and the points An and Cn before and after the point Bn form a concave shape.

That is, for example, when the cross section from which the above-mentioned reference data is obtained is a vertical cross section as shown in FIG. 5, within the vertical cross section, for example, a horizontal measurement traveling direction vector β going rightward in FIG. By setting in advance the direction of the space, that is, the reference vector α pointing upward, as shown in the lower part of FIG. 5, the examination point Bn is the point Bp and the previous point is the point Bp.
If An is the point Ap, the subsequent point Cn is the point Cp, and those points Ap, Bp, Cp form a concave shape, the consideration point Bp from the previous point Ap
The vector VAB going to the right is the point Cp after the consideration point Bp
Since the vector VBC heading upward is upward, their cross product is directed forward with respect to the plane of the drawing, and the judgment vector VC, which is the cross product of the cross product and the right-handed horizontal measurement progress direction vector β, has space. Is directed upward, the sign of the inner product of the determination vector VC and the upward reference vector α becomes positive.

On the other hand, as shown in the upper part of FIG. 5, the study point Bn is a point Bq, the preceding point An is a point Aq, the subsequent point Cn is a point Cq, and the points Aq, Bq, Cq have a convex shape. Is formed, the vector VAB from the previous point Aq to the study point Bq is upward, and the vector VBC from the study point Bq to the later point Cq is rightward. The determination vector VC, which is the cross product of the outer product and the rightward horizontal measurement progress direction vector β, is directed downward, which is not the direction of the space but the direction of the entity. The sign of the inner product of VC and the upward reference vector α is negative. If the shape is flat and the study point Bn, the previous point An and the subsequent point Cn are on a straight line, the vector VA
The outer product of B and the vector VBC is a zero vector, and the above-mentioned determination vector VC, which is the outer product of the zero vector and the measurement traveling direction vector β, is also a zero vector, so that the inner product of the determination vector VC and the above-mentioned reference vector α Is no longer positive.

Therefore, when the inner product (VC · α) between the decision vector VC and the reference vector α has a positive sign, the consideration point Bn and the points An and Cn before and after it form a concave shape. Can be determined, and this is similarly established when the section from which the reference data is obtained is not a vertical section. However, if it is determined in step 28 that the consideration point Bn and the points An and Cn before and after it have formed a concave shape in step 29, the process proceeds to step 30, where the measurement is unnecessary. The study point Bn of the point candidate is determined to be a measurement unnecessary point, and a search for a measurement unnecessary point before and after the study point and a process of deleting the measurement unnecessary point including the study point are performed.

In this process, first, as shown in FIG. 6, a case where the concave portion and the cross section for which the reference data is obtained is orthogonal is illustrated based on the angle θn between the surfaces of the numerical model obtained above. In the cross section, the distance H from the two points of contact between the section line of those surfaces and a circle having a radius r equal to the radius of the tool 5 having the minimum diameter, to the intersection of those section lines,
A point which is obtained by the following arithmetic expression (4) and which is located within a distance less than the obtained distance H from the examination point Bn, which is the measurement unnecessary point, in the point sequence of the reference data is not extracted as a measurement point. Point.

H = {rCos (θ / 2)} / Sin (θ / 2) (4)

That is, the point Bn considered as the above measurement unnecessary point
As shown in FIG. 7, first, at step 41, the distance H is determined by the above equation (4), and then at step 42, as shown in FIG. the point a ₁ and point of interest here, in the following step 43, sought distance Hn of the study points Bn and the point a ₁ of the previous, the next step 44
The distance Hn is compared with the distance H. If the distance Hn is less than the distance H, the process proceeds to step 45, where the target point A ₁
The process returns to step 43 after setting the point A ₂ immediately before to a new target point. In this way, the distance Hn is equal to or greater than the distance H (Hn ≧
When H) is reached, the process proceeds from step 44 to step 46, where the target point immediately before the distance Hn becomes equal to or longer than the distance H is set as a measurement unnecessary point. Also, for the points C ₁ , C _2, ... After the study point Bn, which is the unnecessary measurement point shown in FIG. The distances H are compared, and the target point immediately before the distance Hn becomes equal to or longer than the distance H is determined as a measurement unnecessary point.

After searching and finding the unnecessary measurement points near the examination point Bn in this manner, in this processing, the examination points Bn, which are the above-mentioned unnecessary measurement points, and the measurement unnecessary points obtained by the above-mentioned search, are next obtained. Is deleted from the point sequence of the reference data, and then the point following the deleted point in the point sequence of the reference data is set as the measurement point and the comparison start point, and the point after the comparison start point is set as the next point. The process returns to step 24 with a point to be considered (a point to be considered) and a point ahead of the point to be considered as a target point.

On the other hand, the angle θn between the shape surfaces of the numerical model is determined in the measurement unnecessary portion determination process in the step 26.
Is compared with the previously obtained minimum value θs, and when θn ≧ θs as shown in FIGS. 4A and 4C, the distance dn is equal to dn ≦ ds with respect to the measurement tolerance ds. Therefore, the vicinity of the front and rear points An and Cn does not become a measurement unnecessary part. Therefore, the examination point Bn is determined regardless of whether the examination point Bn and the front and rear points An and Cn form a concave shape. It cannot be a measurement unnecessary point Px. Therefore, when it is determined in step 26 that θn ≧ θs, and it is determined in step 27 that the study point Bn is not a candidate for the unnecessary measurement point, the study point Bn is set as a measurement point in step 31. In a succeeding step 32, it is determined whether or not the target point is the last point on the reference data within the measurement range, and if the target point is not the last point, in a step 33, the consideration point is determined. Is set as a new comparison start point, a point one point ahead of the comparison start point is set as a study point, and a point one point ahead of the study point is set as a target point.
Return to Also, when it is determined in step 29 that the study point Bn and the points An and Cn before and after the study point Bn do not form a concave shape in step 28, the study point Bn becomes a measurement unnecessary point Px. Then, the process proceeds to step 31 described above.

Further, if the above-mentioned examination point is not adopted in step 25 described above, in step 34, as in step 32, the target point is the last point on the reference data within the measurement range. It is determined whether the target point is not the last point.If the target point is not the last point, in step 35, the point one point ahead of the target point is set as a new target point, and the point one point ahead is newly set. As an important consideration, the process returns to step 24. If the target point at that time is the last point in step 32 or step 34, the last point is set as a measurement point in step 36, and the measurement point extraction process ends.

After the measurement point sequence is extracted from the reference data point sequence in this way, the method of this embodiment uses FIG.
As shown in (1), the user of the measurement system causes the minicomputer to display a screen of the extracted measurement point sequence on the terminal device 1; however, the unnecessary measurement points are automatically deleted in the measurement point extraction process here. Since the operation has been performed, the result is confirmed on the screen, and if there is no problem, the teaching on the cross section is terminated. And by repeating such a procedure for the section of the mold to be measured, after teaching the measurement points to the minicomputer for all of the sections to be measured, the minicomputer,
The operation of the three-dimensional measuring device is controlled so that the probe of the sensor of the three-dimensional measuring device sequentially follows the sequence of the measuring points, the measuring operation is performed, and data obtained by the measurement is transmitted to the minicomputer to the system. Is appropriately processed so that the user can easily view it, and is displayed on the screen by the terminal device 1.

As described above, according to the method of this embodiment, when a measurement point is extracted from the point sequence of the reference data, a point to be examined, which is an unnecessary measurement point, is not automatically extracted as a measurement point. Therefore, when teaching a shape measurement procedure of the shape of the object to the shape measuring device using the point sequence of the measurement points, the number of steps of manually deleting unnecessary measurement points at the last stage of the teaching can be reduced. Can be largely omitted, the number of man-hours required for teaching can be further reduced compared to the conventional method, and only unnecessary measurement points can be reliably removed, so that there is no possibility of erroneously deleting necessary measurement points. be able to.

Further, according to the method of this embodiment, when obtaining the angle between the surfaces of the numerical model at positions respectively corresponding to points before and after the point to be examined in the point sequence of the reference data,
An angle at which the value obtained by dividing the inner product of the normal vectors at each of the points before and after the point of interest by the product of the absolute values of the normal vectors with a negative sign is the cosine value Is obtained and the angle is defined as the above-described angle, so that the angle of the surface of the numerical model at the position corresponding to each of the points before and after the point to be examined can be easily and accurately obtained.

Further, according to the method of this embodiment, when determining whether or not the point to be examined and the points before and after it form a concave shape, the measurement progress direction vector is determined within the cross section in which the reference data is created. And a reference vector orthogonal to it and directed to a certain space in advance, and a vector from the point before the point to be examined to the point to be examined and the point from the point to be examined to the point after the point to be examined. The cross product of the heading vector and the cross product of the measurement progress direction vector are obtained and used as the judgment vector.If the inner product of the judgment vector and the reference vector has a positive sign, the points to be examined and the Since it is determined that the points before and after form a concave shape, it is possible to easily and accurately determine whether the point to be examined and the points before and after the concave form a concave shape.

Further, according to the method of this embodiment, based on the angle between the surfaces of the numerical model, a cross-section line of those surfaces and a radius equal to the radius of the tool having the minimum diameter in a cross section orthogonal to the surfaces. The distance from the two points of contact with the circle to the intersection of their cross-sectional lines is determined, and in the point sequence of the reference data, the distance is less than the determined distance from the point to be examined that is not extracted as the measurement point. Points, other than the points to be considered, the points located in the measurement-unnecessary parts in the reference data corresponding to the unprocessed parts with the tool having the minimum diameter are also not extracted as the measurement points.
When extracting measurement points from the reference data point sequence, not only the points to be considered but also points that become more unnecessary can be automatically excluded without extracting them as measurement points. When teaching the shape measurement procedure of the object to the shape measuring device using the rows, the man-hour for manually deleting unnecessary measurement points at the last stage of the teaching is further reduced, and the man-hour required for the teaching is further reduced. be able to.

Although the present invention has been described with reference to the illustrated examples, the present invention is not limited to the above-described example, and may be applied to, for example, shape measurement of an object other than a body panel molding die. The same operation and effect as in the example can be obtained.

[0044]

As described above, according to the teaching method of the shape measurement procedure of the present invention, when a measurement point is extracted from a point sequence of reference data, a point to be examined, which is an unnecessary measurement point, is not extracted as a measurement point, but is automatically extracted. Therefore, when teaching a shape measuring procedure of the shape of the object to the shape measuring device using the point sequence of the measuring points, it is possible to eliminate unnecessary measurement points manually at the last stage of the teaching. The number of man-hours required for teaching can be greatly reduced, so that the man-hour required for teaching can be further reduced compared to the conventional method. Moreover, since only unnecessary measurement points can be reliably removed, the necessary measurement points may be erroneously deleted. Can be eliminated.

When calculating the angle between the surfaces of the numerical model at positions corresponding to the points before and after the point to be examined in the point sequence of the reference data, respectively, the points before and after the point to be examined are determined. The value obtained by dividing the inner product of the normal vectors by the product of the absolute values of the normal vectors is obtained as an angle at which a value obtained by adding a negative sign becomes a cosine value, and the angle is defined as the above-described angle. Then, the angle between the surfaces of the numerical model at the positions respectively corresponding to the points before and after the point to be examined can be easily and accurately obtained.

When judging whether or not the point to be examined and the points before and after the point form a concave shape, in the section in which the reference data is created, the measurement progress direction vector and the direction in which And a reference vector pointing to the point to be examined is set in advance, and an outer product of a vector from the point before the point to be examined to the point to be examined and a vector from the point to be examined to the point after the point to be examined, and the above measurement The outer product of the traveling direction vector is obtained and used as a determination vector.If the inner product of the determination vector and the reference vector has a positive sign, the point to be considered and the points before and after it form a concave shape. If it is determined that the point is examined, it is possible to easily and accurately determine whether the point to be examined and the points before and after the point form a concave shape.

Further, based on the angle between the surfaces of the numerical model, two points of contact between a sectional line of those surfaces and a circle having a radius equal to the radius of the tool having the minimum diameter in a cross section orthogonal to those surfaces are obtained. Find the distance to the intersection of those section lines,
In the point sequence of the reference data, a point at a distance less than the obtained distance from the point to be examined that is not extracted as the measurement point, that is, a part to be processed by the tool having the minimum diameter other than the point to be examined. If the points located in the measurement-unnecessary part in the reference data corresponding to are not extracted as the measurement points, when extracting the measurement points from the point sequence of the reference data, not only the points to be examined but also more Can be automatically excluded without extracting points that are unnecessary measurement points as measurement points, and teaching the shape measurement procedure of the object to the shape measurement device using the point sequence of the measurement points. In the last stage of the process, the man-hour for manually removing unnecessary measurement points is further
The number of steps required for teaching can be further reduced.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a measurement point extraction process in one embodiment of a teaching method of a shape measurement procedure according to the present invention.

FIG. 2 is an explanatory view showing a method of obtaining a minimum value of an angle between both side surfaces of a concave portion so that a residual amount of machining with a tool having a minimum diameter falls within a measurement tolerance in the method of the embodiment.

FIG. 3 is an explanatory diagram showing a method for obtaining an angle between surfaces of numerical data at positions corresponding to points before and after a study point in the method of the embodiment.

FIG. 4 is an explanatory diagram showing a comparative example of the minimum value of the sandwiching angle and the sandwiching angle of the surface of the numerical data.

FIG. 5 is an explanatory diagram showing a method for determining whether or not a point to be considered and points before and after the method form a concave shape in the method of the embodiment.

FIG. 6 is an explanatory diagram showing a method of searching for a measurement unnecessary point near a study point in the method of the embodiment.

FIG. 7 is a flowchart showing a procedure for searching for a measurement unnecessary point near a study point in the method of the embodiment.

FIG. 8 is an explanatory diagram showing a teaching procedure of a conventional teaching method of a shape measuring procedure, and a right flowchart is an explanatory diagram showing a teaching procedure of a teaching method of a shape measuring procedure of the embodiment.

FIG. 9 is a flowchart showing measurement point extraction processing in the conventional method.

FIG. 10 is an explanatory diagram showing a method of measuring point extraction processing in the conventional method.

FIG. 11 is an explanatory diagram showing a state of occurrence of an unprocessed portion at a corner of a concave portion of an object during machining.

FIG. 12 is an explanatory diagram showing unnecessary measurement points in a measurement unnecessary portion corresponding to the above-mentioned unprocessed portion at a corner of a concave corner portion in a reference data point sequence or a measurement data point sequence extracted therefrom. It is.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Terminal device 2 Mouse 3 Keyboard 4 Mold 5 Tool with minimum diameter 6, 7 Both sides of recess

Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) G05B 19/18-19/46 B25J 3/00-3/04 B25J 9/10-9/22 B25J 13/00-13 / 08 B25J 19/02-19/06

Claims (4)

(57) [Claims] 1. A numerical model representing an assumed shape of an object in three dimensions in detail from a numerical model representing a cross-sectional shape of the object by a point sequence and for each point in the point sequence at a position corresponding to the point. Create reference data having the normal vector of the surface of the numerical model, extract points that need to be measured based on a predetermined measurement standard from the point sequence of the reference data as measurement points, and use the point sequence of the measurement points. When teaching a shape measurement procedure of the shape of the object to the shape measuring device, regarding the concave portion such that an error generated by unprocessed tool with the smallest diameter tool among the tools used for processing the object falls within the measurement tolerance. The two sides of the recess are flat
In this case, the minimum value of the angle between the two side surfaces is obtained in advance as a reference angle, and at the time of extracting the measurement points, at positions corresponding to points before and after the point to be considered in the point sequence of the reference data, respectively. When the angle between the surfaces of the numerical model is less than the reference angle, and the point to be examined and points before and after it form a concave shape, the point to be examined is measured. A method of teaching a shape measurement procedure, characterized by not extracting a point. 2. When obtaining an angle between surfaces of the numerical model at positions respectively corresponding to points before and after a point to be examined in a point sequence of the reference data, The value obtained by dividing the inner product between the normal vectors in each case by the product of the absolute values of the normal vectors is given as a cosine value, and the angle sandwiching the angle is obtained. 2. The method of teaching a shape measurement procedure according to claim 1, wherein 3. A method for determining whether or not a point to be considered and points before and after the point form a concave shape, includes: And a reference vector directed toward a certain point is set in advance, and a cross product of a vector directed from the point before the point to be examined to the point to be examined and a vector directed from the point to be examined to the subsequent point is Finding the outer product of the measurement progress direction vector and using it as a determination vector, when the inner product of the determination vector and the reference vector has a positive sign, the point to be considered and the points before and after it are concave. 3. The method according to claim 1, wherein it is determined that a shape is formed. 4. A contact point between two points of a cross-section line of the surface and a circle having a radius equal to the radius of the tool having the minimum diameter in a cross section orthogonal to the surface based on an angle between the surfaces of the numerical model. From the points of the reference data, a point less than the obtained distance from the point to be examined, which is not extracted as the measurement point, is also extracted as the measurement point. The method of teaching a shape measurement procedure according to any one of claims 1 to 3, wherein the method is not performed.