JPS61137004A - Method for measuring semi-spherical free curved body - Google Patents

Abstract

PURPOSE:To perform measurement with high accuracy at a high speed, by aligning the center of a semi-spherical free curved body with the rotation center of a measuring device before respectively rotating the measuring device and a work table. CONSTITUTION:A work table 11 is three-dimensionally moved by the movement of an up-and-down movable table 2 and an X-Y table 8 to allow the center of an object 13 to be measured to align with the rotation center of a measuring device 18. By rotating the object 13 to be measured in a horizontal plane by the rotation of the rotary table 8, the longitude of the object 13 to be measured is scanned by the measuring device 18 while, by rotating the measuring device 18 by driving a motor 21, the latitude of the object 13 to be measured is scanned by the measuring device 18. By this method, surface coordinates are measured with respect to each measuring point determined on the surface of the object 13 to be measured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for measuring the coordinates of each point on the surface of a hemispherical free-form surface.

[Conventional technology]

Until now, there was no dedicated machine for measuring the surface coordinates of hemispherical free-form surfaces.

In cases where the object to be measured is not limited to a hemispherical free-form surface body, a method for measuring the surface coordinates of the object to be measured is to fix the object to be measured and move the measuring instrument in three-dimensional directions with respect to the object to be measured. There is a way to measure while doing so.

[Problem that the invention seeks to solve]

The above configuration has the disadvantage that the measuring device becomes large because the measuring device is moved three-dimensionally to accommodate objects of any shape, not just hemispherical free-form surfaces.

In addition, in order to specify the surface shape of a hemispherical free-form surface,
Compared to when the object to be measured has a geometric shape, it is necessary to take a large number of measurement points, but when measuring a hemispherical free-form surface using the above conventional technique, the measuring instrument must be moved between the measurement points. Since the measuring instrument must be moved in two or three dimensions each time, it takes time to move the measuring instrument. In this way, there is a drawback that the total measurement time is long because a large number of measurement points are taken as described above while moving over time.

The disadvantage of the conventional technique that it takes a long time to measure a hemispherical free-form surface object is particularly noticeable when a contact type measuring instrument is used. In other words, with contact-type measuring instruments, the working time required for measurement is not only moving the measuring instrument between measurement points, but also the time required for the probe measuring pressure to reach a constant pressure. Since this amount of time is required for each measurement point, the total measurement time becomes even longer.

In addition, when a contact type is used as a measuring device in the above-mentioned conventional technology, there are drawbacks that generally exist in the contact method.
There are also disadvantages in that measures against abrasion of the contacts are required, and it is impossible to measure irregularities with an area smaller than the contact area of the contacts.

On the other hand, non-contact measuring instruments generally require that the distance from the measuring instrument to the measurement point of the object to be measured be maintained at a predetermined distance, and that the position and direction of the measuring instrument be on the normal line to the measurement point of the object to be measured. This is an important requirement for improving measurement accuracy. However, when trying to use a non-contact type measuring device in the above conventional technology,
Since the measuring instrument moves in three dimensions, it is difficult to satisfy any of the above requirements. Therefore, in this case,
There is a drawback that sufficient measurement accuracy cannot be obtained.

[Means for solving problems]

The present invention provides a method for measuring a hemispherical free-form surface object that solves the above-mentioned problems and is capable of measuring at high speed and with high precision. By adjusting the movement, the center of the hemispherical free-form surface body is aligned with the rotation center of the rotatable measuring instrument, and then the surface of the hemispherical free-form surface body is scanned by rotating the measuring instrument and the work table respectively. This is carried out by a hemispherical free-form surface body measurement method characterized by measuring the surface coordinates of the hemispherical free-form surface body.

[Effect]

The above-mentioned method for measuring a hemispherical free-form surface body allows the work table to be moved and rotated in three dimensions, and the measuring instrument to be rotated.Compared with conventional techniques, there is no need to move the measuring instrument in three dimensions. Since there is no such thing, the structure for moving the measuring instrument is greatly simplified, and the structure for moving the work table is simpler than moving the measuring instrument, so overall it is possible to downsize the measuring device. .

Furthermore, since the measuring instrument and the work table are each rotated to scan the surface of the hemispherical free-form surface, the entire curved surface portion of the hemispherical free-form surface can be measured.

Furthermore, even if the measuring instrument and work table rotate, the alignment between the measuring instrument and the hemispherical free-form surface body is maintained.
The measuring device can be positioned on the normal line to the measuring point on the surface of the hemispherical free-form surface. Furthermore, the distance between the measuring device and the measuring point on the hemispherical free-form surface body is kept approximately constant. Therefore, it is possible to perform highly accurate measurement using a non-contact type measuring device. Also, a contact type measuring device may be used.

Once aligned, the measuring point can be moved by rotating one or both of the work table and the measuring instrument, improving work efficiency and aligning the measuring instrument and the measuring point compared to conventional techniques. Accuracy can be improved.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a partially cutaway front view of a main part of an embodiment of the present invention. 2 is a longitudinal cross-sectional view taken along the line ■--■ in FIG. 1, and FIG. 3 is a cross-sectional view taken along the line m--m in FIG. In the figure, l is the pedestal, 2 is the vertically movable table, 3 is the guide bar fixed to the vertically movable table 2, 4 is the bearing of the guide bar 3 fixed to the pedestal 1, and 5 is the vertically movable table 2 as shown by the arrow Z.
The motors for vertical driving are shown as follows.

A rotary table 6 is attached on top of the vertically movable table 2. Reference numeral 7 indicates a motor for rotating the rotary table 6 as indicated by arrow A.

An X-Y table 8 is mounted on the rotary table 6. 9 is a motor for horizontally moving the X-Y table 8 as shown by arrow X; 0 is a motor for horizontally moving the X-Y table 8 as shown by arrow
The motors for driving horizontal movement are shown as follows.

A work table 11 is mounted on the X-Y table 8. An object to be measured 13, which is a hemispherical free-form surface, can be clamped to the work table 11 via a jig 12.

Due to the above-mentioned purchase, the object to be measured 13 can be moved in three dimensions by the action of the vertical movement table 2 and the X-Y table 8, and the object to be measured 13 can be moved by the action of the rotary table 6. It can rotate in the direction along its own latitude.

Next, the measuring instrument support arm will be explained. Frame 1
A pair of bearing stands 14 are erected on the bearing stand 14, and a shaft 16 is rotatably supported in a horizontal plane by a bearing 15 of the bearing stand 14, and a gate-shaped support arm 17 is attached to the shaft 16. A measuring device 18 for non-contact displacement measurement is provided at the center of the support arm 17, and 19 indicates carancraate.

A pulley 2o is attached to one of the shafts 16, and a pulley 2o for outputting various motors 2, such as a DC motor or a servo motor, as a drive source fixed to the frame l.
A transmission means is stretched between the belt 23 and the belt 23. Therefore, by driving the motor 21, the measuring instrument 18 can revolve more than 180 degrees between the extreme positions C and 0, as indicated by the arrow B shown in FIG. In FIG. 1, the bearing stand 14 on the other shaft 16 side is provided with an angle sensor 24 for detecting the angular position of the measuring instrument 18 during its revolution. Although a gate-shaped structure for supporting the measuring instrument has been described above, a cantilevered arm may be used instead.

Next, a method for measuring a hemispherical free-form surface object using the hemispherical free-form surface object measuring device described above will be described. First, the object to be measured 13 is placed on the work table 11 of the device using the jig 1.
Set by 2. In the autumn, leave the work table 11 at its current position, or move the work table 11 to the work table 1 if the standard position for preliminary measurements described below is fixed.
1 to the standard position, and the surface coordinates of a plurality of measurement points on the surface of the object to be measured 13 are preliminarily measured by the measuring device 18. Based on the results of this measurement, a calculation means such as a central control device connected to the measuring device calculates the
Calculate the center of 3. In this case, the center of the object to be measured can be defined as a point halfway between the center of the maximum inscribed sphere for the hemispherical free-form surface of the object to be measured and the center of the minimum circumscribed sphere for the same surface. , or simply the center of the maximum inscribed method or simply the center of the minimum circumscribed sphere. Next, move the work table 11 to the vertical movement table 2.
By moving the X-Y table 8 three-dimensionally, the center of the object 13 determined by the ice formation calculated above is made to coincide with the center of revolution of the measuring instrument 18. Next, the measuring device 18 scans the longitude of the measuring object 13 by rotating the measuring object 13 in a horizontal plane by rotating the rotary table 8, and the measuring device 18 is caused to revolve by driving the motor 21. The measuring instrument 18 scans the latitude of the object 13 to be measured, and measures the surface coordinates of each measurement point defined on the surface of the object 13 to be measured. In this measurement, the object to be measured 1
3 and the center of revolution of the measuring device 18 are aligned as described above, and the surface of the object to be measured is a hemispherical free-form surface, so the object to be measured 13 and the measuring device 18 are at an altitude of ψ゛They maintain a constant distance from each other at near values of and face each other at right angles. Therefore, it is possible to increase the precision and speed of coordinate measurement on the surface of the object to be measured. Although it is possible to select any point on the hemispherical free-form surface of the object to be measured 13 as the measurement point of the object to be measured 13, for example, it is possible to select an arbitrary point at an arbitrary angular interval along the longitude and latitude of the object to be measured 13. Measurement points can be used. In this case, in order to move the measurement object between measurement points belonging to the same longitude, it is sufficient to simply revolve the measuring instrument 18 without moving the object to be measured, and also to move the measurement object between measurement points belonging to the same latitude. To do this, it is sufficient to simply rotate the object to be measured 13 without moving the measuring instrument. Therefore, the work of moving the measurement object between all measurement points of the object to be measured 13 is as follows:
Compared to conventional measuring devices, it is possible to shorten the required time and improve positioning accuracy.

Furthermore, if necessary, it can be used as a tool for various systems such as CAD and CAM, such as by creating a graph using the surface coordinates of the object to be measured or by using it as control data for other machines. wide.

In the above embodiment, it was explained that a non-contact type measuring device is used, but even if a contact type measuring device is used, coordinate measurement can be performed with high precision and high speed. It is possible to obtain the same effects as those described in the above embodiments, such as being able to be used for CAM and the like. Therefore, in the present invention, the measuring device can be freely selected from contact type and non-contact type, taking into consideration required accuracy, measurement accuracy, cost, etc.

〔Effect of the invention〕

As explained above, according to the present invention, after aligning the center of the hemispherical free-form surface body that is the object to be measured with the rotation center of the measuring instrument, the longitude and latitude of the hemispherical free-form surface body are scanned, and the coordinates are Because it performs measurement, it can be measured with high precision and at high speed, and has the effect of having a wide range of applications, including not only measurement but also control of other machines.

[Brief explanation of drawings]

FIG. 1 is a front view of the main part showing an example of a hemispherical free-form surface measuring device used in one embodiment of the present invention, with a partial cross section. FIG. 2 is a longitudinal sectional view taken along line nm in FIG. 1. , FIG. 3 is a cross-sectional view taken along the line mm in FIG. 1. ■... Frame 2... Vertical table 5/P/Motor for vertical drive 6... Rotary table 7... Motor for rotational drive 8... X-Y table 9... X direction Motor 10 for movement...Motor 11 for movement in the Y direction...Work table 12...Jig 13...Object to be measured 14...Bearing stand 15...Bearing 16...Shaft 17 ...Support arm 18...Measuring instrument 21...Motor 24 for rotating the measuring instrument...Angle sensor, Fig. 1

Claims (1)

[Claims] By moving and adjusting the work table on which the hemispherical free-form surface body is placed in three-dimensional directions, the center of the hemispherical free-form surface body is aligned with the rotation center of the rotatable measuring instrument, and then the measuring instrument and work table are moved. 1. A method for measuring a hemispherical free-form surface object, comprising: scanning the surface of the hemispherical free-form surface object by rotating each of the hemispherical free-form surface objects, and measuring the surface coordinates of the hemispherical free-form surface object.