JPH10260033A - Three-dimensional measuring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically measure an object without interference between a prove and the object even when the object is set unsuitably in a three- dimensional measuring system which employs a rotational prove. SOLUTION: By photographing a work 7 with image pick-up means 8, 9, calculating temporary new coordinate system from collected image information, and performing temporary measurement to provide true new coordinate system on the basis of the temporary new coordinate system, true new coordinate system is determined in which the work 7 is a basis. Setting the determined true new coordinate system to be standard, angle indication values ϕ, θ of the rotational prove 17 which are included in measurement indications such as a part program is determined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional measuring machine using a rotary probe, and more particularly, to preventing automatic interference between the rotary probe and an object to be measured, thereby facilitating automatic measurement. The present invention relates to a three-dimensional measurement system.

[0002]

2. Description of the Related Art In a CNC three-dimensional measuring system, a probe is automatically driven by a preset part program according to a command from a host computer. CN
When measuring the same object multiple times with the C three-dimensional measurement system, use a jig that fixes the object so that the set position of the object does not shift. The measurement has been realized.

[0003]

However, even if a fixing jig is used, when a rotary probe is used in the three-dimensional measuring system, a slight displacement of the set position of the measured object and processing of the reference surface of the measured object. Due to the accuracy or the like, the movement locus of the probe may interfere with the measured object. This will be described with reference to FIG. As shown in FIG. 9 (a), the rotation angle θ of the rotary probe 81 is set so that when the work 82 is set at a position and posture assumed in advance, the shape of the small hole 83 to be measured of the work 82 is changed. 81 is set to the most suitable angle. However, as shown in FIG. 8B, when the work 82 is set to be inclined, the direction of the small hole 83 and the direction of the probe 81 are shifted, and the probe 81 82
May interfere. In particular, when the small hole to be measured is close to the diameter of the probe or when the rotatable angle of the rotary probe is an intermittent type, such a tendency is remarkable. For such a reason, when a rotary probe is used, it is difficult to perform automatic measurement without using any fixing jig.

The present invention has been made in view of such a point, and in a three-dimensional measurement system using a rotary probe, even if the measurement object is set with a deviation, the probe and the measurement object may interfere with each other. It is an object of the present invention to provide a three-dimensional measurement system that does not interfere with automatic measurement without any problem. Another object of the present invention is to provide a three-dimensional measurement system that enables automatic measurement using a rotary probe without using a fixing jig.

[0005]

According to the present invention, there is provided a three-dimensional measuring system, comprising: an image pickup means for picking up an image of a measurement object; and a temporary image based on the measurement object based on image information of the measurement object obtained by the image pickup means. Means for calculating a new coordinate system, means for temporarily measuring the measurement target based on the temporary new coordinate system calculated by this means, and calculating a true new coordinate system based on the measurement target, Means for setting an angle indication value of the rotary probe included in the measurement instruction based on the true new coordinate system calculated by this means.

According to the present invention, an object to be measured is imaged by the imaging means, a temporary new coordinate system of the object to be measured is calculated from the obtained image information, and the true new coordinate system is calculated based on the temporary new coordinate system. By performing tentative measurement for obtaining the system, a true new coordinate system based on the measurement target is obtained. Then, based on the obtained true new coordinate system, the angle instruction value of the rotary probe included in the measurement instruction of the part program or the like is determined, so that the position, orientation, and the like of the measurement target are scheduled. Even when the position and orientation are different from each other, the most appropriate angle instruction value can be set based on the coordinate system of the measurement target. For this reason, even if a rotary probe is used, it is possible to avoid interference between the measurement target and the probe, and automatic measurement can be performed without using a fixing jig or the like.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A three-dimensional measuring system according to an embodiment of the present invention will be described below with reference to the accompanying drawings. FIG.
1 is a perspective view showing a schematic configuration of this system. On a known special pneumatic anti-vibration device 1, a special mount 2 for the anti-vibration device is mounted. Further, on one side of the special mount 2, a three-dimensional measuring machine 3 is mounted, and on the other side, Has the first lighting device 4
Are installed respectively. The coordinate measuring machine 3 has a base 11 serving as a base, and a bridge-shaped arm that moves in the Y-axis direction along Y-axis guides 12 at both ends of the base 11 and connects both ends of the base 11. A support 13; a Z-axis guide 15 that moves in the X-axis direction along the X-axis guide 14 of the arm support 13; an arm 16 that moves in the Z-axis direction along the Z-axis guide 15; And a rotary probe 17 for measurement supported by the support 16. Further, the coordinate measuring machine 3 is provided with an automatic probe exchange device 18 for exchanging probes.

A measurement area of the coordinate measuring machine is formed above the surface plate 11 of the coordinate measuring machine 3, and an image pickup area is formed above the first illumination device 4. A stage drive mechanism 5 is provided so as to connect these two areas. The stage driving mechanism 5 includes two parallel rails 21 that connect the surface plate 11 of the coordinate measuring machine 3 and the first lighting device 4, and a U-shaped slide table guided and moved by the parallel rails 21. And a motor 23 for driving the slide table 22 and a screw-shaped drive shaft 24. The pallet 6 is mounted on the slide table 22. The pallet 6 constitutes a stage on which the work 7 is placed, and is composed of a transparent glass plate 31 and a frame 32 mounted on a peripheral portion of the glass plate 31. A positioning hole 33 is formed in the frame 32, and the hole 33 and a positioning boss 34 provided on the slide table 22 are fitted to position the pallet 6 on the slide table 22.

Above and beside the work 7 arranged on the pallet 6, CCD cameras 8, 9 for picking up the work 7 are provided.
Are arranged respectively. On the opposite side of the work 7 from the CCD camera 9, a second illumination device 10 is arranged. The lighting devices 4 and 10 each include a case 41 in which a light source (not shown) is housed, and a translucent plate 42 that seals the case 41 and uniformizes the light from the light source.

FIG. 2 is a diagram showing details of the rotary probe 17. A motor (not shown) is built in the probe head 45 attached to the tip of the arm 16, and the touch signal probe main body 46 and the tracing stylus 47 attached to the tip by the motor are shown in FIG. As shown in a), the arm 16 can rotate by a specified angle φ around the central axis, and as shown in FIG. 4B, can rotate by a specified angle θ along a vertical plane from the central axis. It is configured as follows.

FIG. 3 is a block diagram showing a signal / information processing system of this system. Image information picked up by the CCD cameras 8 and 9 is supplied to an image processing device 51, where characteristic points of the work 7 are extracted by image processing, and a rough set position and the like of the work 7 are obtained by image recognition processing. Can be The three-dimensional measuring machine data processing device 52 constructs a temporary new coordinate system of the workpiece 7 from information such as the workpiece position, converts a necessary part of a part program that defines a procedure of the three-dimensional measurement, and performs a temporary measurement. Is given to the controller 53 or a true new coordinate system is calculated based on the provisional measurement result.
4 are supplied with designated angles φ and θ of the rotary probe 17. The controller 53 drives the stage driving mechanism 5 and the coordinate measuring machine 3. Also, the probe controller 54
The rotary probe 17 is driven to rotate based on the specified angles φ and θ.

Next, the operation of the present system configured as described above will be described. FIG. 4 is a flowchart showing a measurement procedure of the present system. At the start of measurement, pallet 6
Are arranged in an imaging area where imaging by the CCDs 8 and 9 is possible. In this state, when the work 7 is carried onto the pallet 6 by a transfer means such as a hand or a robot (S1), C
The work 7 is imaged by the CD cameras 8 and 9, and the rough work position and the like are extracted (S2). At this time,
The illuminating light from the first illuminating device 4 passes through the hollow portion of the slide table 22 and the glass plate 31 of the pallet 6 between the parallel rails 21 to illuminate the work 7 from below. Since the CCD camera 8 captures an image of the work 7 from above the opposite side of the lighting device 4, the work 7 is backlit and the contrast between the work and the background is reduced as shown in FIG. Obtained clear image information is obtained.
Similarly, C that receives the illumination light from the second illumination device 10
The image information of the side of the work 7 obtained by the CD camera 9 is also
As shown in FIG. 5B, clear image information is obtained in which the contrast between the work portion and the background is enhanced.

When the image information is supplied to the image processing device 51, the image processing device 51 calculates a rough work position or the like from the supplied image information. That is, as shown in FIG. 6, after the image information is binarized by the binarization section 61, the edge portion of the binary image is extracted by the contour extraction section 62. Subsequently, in order to increase the processing efficiency of the pattern matching, a characteristic portion, for example, a corner coordinate, is extracted from the contour information by the characteristic extracting portion 63, and the characteristic portion and the basic pattern storage portion 64 are extracted.
And some basic patterns stored in the matching unit 6
Matched at 5. Thereby, based on the obtained work pattern, the position calculating unit 66 and the main dimension calculating unit 67
Calculates a rough work position and a work main dimension from the characteristic portion of the image. The obtained work pattern, work position, work main dimension, and the like are transferred to the coordinate measuring machine data processing device 52.

In the coordinate measuring machine data processing device 52, first, as shown in FIG.
Selects one of the part programs stored in the pattern-specific part program storage unit 72 based on the work pattern information provided from the image processing apparatus 51.
Next, from the work position in the image processing coordinate system obtained by the image processing device 51, a temporary new coordinate system based on the work is constructed (S3), and the teaching previously recorded in the selected part program or the like is performed. The conversion formula from the reference coordinate system at the time to the temporary new coordinate system is calculated, and the measurement point coordinate values of the temporary measurement program part for constructing the true new coordinate system in the selected part program are obtained. The data is converted into a temporary new coordinate system by the conversion formula (S4).

Next, a movement or measurement command corresponding to the measurement procedure of the provisional measurement portion of the part program is given to the controller 53 to execute the provisional measurement (S5). From the obtained measurement data, a conversion formula to the true new coordinate system is calculated (S6). Further, using the calculated conversion formula to the true new coordinate system, all the designated coordinate values of the remaining portion except for the provisional measurement part in the part program are converted by the conversion formula to the true new coordinate system ( S7). If the part program includes an angle command value for the rotary probe, the rotation angles φ and θ of the rotary probe 17 are adjusted so as to compensate for the deviation caused by the true new coordinate system. φ ′,
θ ′ is given (S8), and measurement is started (S8).
9).

Here, as shown in FIG. 8, the commanded rotation angles φ ′ and θ ′ of the rotary probe 17 are expressed in the XY coordinate system of the measuring machine.
Z, assuming that the true new coordinate system is X'Y'Z ', in the new coordinate system X'Y'Z', the inclination of the probe 17 specified by the initial designated rotation angles φ and θ is the measuring machine coordinate system. It is determined by calculating how much the rotation angles φ ′ and θ ′ will be based on XYZ. In the case of a probe whose rotation angle can be continuously indicated, the obtained rotation angles φ ′, θ ′
Is given as it is as the commanded rotation angle, and in the case of the intermittent type (for example, the rotation angle is in increments of 7.5 °), the rotation angle closest to the obtained rotation angles φ ′ and θ ′ may be given as the designated rotation angle.

[0017]

As described above, according to the present invention, an object to be measured is imaged by the imaging means, and a temporary new coordinate system of the object to be measured is calculated from the obtained image information. Based on the above, a tentative measurement for obtaining a true new coordinate system is performed, thereby obtaining a true new coordinate system based on the measurement target, and using the obtained true new coordinate system as a reference, such as a part program. Since the angle indication value of the rotary probe included in the measurement instruction is determined, the position of the measurement target,
Even when the posture is out of the expected position or posture, the most appropriate angle indication value can be set based on the coordinate system of the measurement target, and there is no automatic interference between the measurement target and the rotary probe. This has the effect of enabling measurement.

[Brief description of the drawings]

FIG. 1 is a perspective view of a three-dimensional measurement system according to an embodiment of the present invention.

FIG. 2 is a front view and a side view of a rotary probe of the same system.

FIG. 3 is a block diagram of a signal / information processing system of the system.

FIG. 4 is a flowchart showing a measurement procedure of the system.

FIG. 5 is a diagram showing an example of image information obtained by the system.

FIG. 6 is a functional block diagram illustrating a configuration of an image processing apparatus in the system.

FIG. 7 is a functional block diagram showing a configuration of a CMM data processing device in the same system.

FIG. 8 is a diagram showing a conversion example of a rotation angle of a rotary probe in the system.

FIG. 9 is a diagram for explaining a conventional problem using a rotary probe.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Anti-vibration apparatus, 2 ... Special mount for anti-vibration value, 3 ... 3D measuring machine, 4 ... First illumination device, 5 ... Stage drive mechanism, 6
... Pallet, 7 ... Work, 8,9 ... CCD camera, 10
... Second lighting device, 17 ... Rotary probe.

Claims (1)

[Claims] An imaging unit configured to capture an image of a measurement target; a unit configured to calculate a temporary new coordinate system based on the measurement target from image information of the measurement target obtained by the imaging unit; Means for temporarily measuring the measurement object based on the provisional new coordinate system to calculate a true new coordinate system based on the measurement object; and based on the true new coordinate system calculated by the means. Means for setting an angle instruction value of the rotary probe included in the measurement instruction.