JP3112056B2 - Three-dimensional shape measurement method and device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-dimensional shape measuring method for irradiating a workpiece with laser light and an apparatus therefor.

[0002]

2. Description of the Related Art Conventionally, apparatuses for measuring a three-dimensional shape are disclosed in Japanese Patent Application Laid-Open Nos.
No. 07, JP-A-60-196608 and the like. JP-A-5-149723 discloses that an object to be measured is arranged between a light emitting unit arranged at an upper part and a light receiving unit arranged at a lower part, and a laser beam is emitted from the light emitting part toward the light receiving part. It measures the distance between the measured object and the reference rod. Japanese Patent Application Laid-Open No. 4-84707 discloses a method in which a slit light is radiated from above to a surface of a measuring object, a light cutting line projected on the surface of the measuring object is imaged, and a three-dimensional image is obtained from the light cutting line image. This is for calculating coordinate values. Japanese Patent Application Laid-Open No. 60-196608 discloses a technique for continuously detecting the height of a cross section of an object by a light cutting method in which a light beam is scanned obliquely from above the object.

[0003]

However, in the above-described conventional apparatus, the laser light is irradiated onto the work from above or the work is scanned by a rotating mirror, so that the irradiated laser light is irregularly reflected to the surroundings. For this reason, a protection guard is provided around the work, or a measure that does not pose a risk to the eyes of the operator is required. Therefore, there is a problem that the configuration around the apparatus is complicated.

[0004] It is an object of the present invention to provide a three-dimensional shape measuring method and a three-dimensional shape measuring method capable of simplifying the configuration including peripheral devices.

[0005]

A three-dimensional shape measuring method according to the present invention irradiates a work with laser light and measures the three-dimensional shape of the work based on reflected light of the laser light. In the movable section of the XY table mounted on a substantially horizontal surface, only the laser displacement meter for directing the laser light upward and irradiating the laser light is provided, and the work is held by the work holding means above the XY table. It is a technical means to store distance data to the work measured by the laser displacement meter at each coordinate of the XY table together with each coordinate, and calculate a contour shape of the work based on the distance data. .

A three-dimensional shape measuring apparatus for irradiating a work with laser light and measuring the three-dimensional shape of the work based on reflected light of the laser light according to the present invention. An XY table placed on top,
Provided on the movable portion of the XY table, the laser displacement gauge which irradiates with <br/> directed a laser beam upward, the workpiece X
Work holding means arranged and held above the Y table; distance data storage means for storing distance data to the work measured by the laser displacement meter at each coordinate of the XY table together with the coordinates; distance data storage means based on the stored the distance data is provided with a shape calculating unit for calculating a three-dimensional shape of the workpiece, the movable part of the XY table, the laser displacement
It is a technical measure that only a meter is provided .

[0007]

According to the present invention, when a work is arranged above an XY table and a movable portion of the XY table is movable, a laser beam is radiated upward from a laser displacement meter provided in the movable portion, and each coordinate is adjusted. Is measured and stored as distance data. Since the distance data to the work is stored together with each coordinate in the XY table, the three-dimensional shape of the work is calculated based on each coordinate and the distance data.

[0008]

According to the present invention, in calculating the shape of a work, the three-dimensional shape of the work can be calculated based on the coordinates of the XY table and the distance data to the work measured at the coordinates. May be measured only in one direction from the top of the XY table to the top. Therefore, the irradiation direction of the laser beam in the laser displacement meter only needs to be upward, and the scanning of the laser beam itself is not performed, so that the irradiated laser beam does not irregularly reflect to the periphery. As a result, it is not necessary to perform a device for preventing the influence of irregular reflection of the laser light and a process for protecting workers around the work to be irradiated with the laser light. A measurement can be made.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG.
1 shows the appearance of the three-dimensional shape measuring apparatus 100 according to the embodiment of the present invention. In FIG. 1, reference numeral 2 denotes an XY table as an orthogonal table provided on the surface plate 1, each of which is electrically driven X
It has a shaft actuator 3 and a Y-axis actuator 4 provided on the X-axis actuator 3, and a movable portion of the Y-axis actuator 4 is provided with a laser displacement gauge 5.

As shown in FIG. 2, the laser displacement meter 5 measures a distance L from the laser displacement meter 5 to a measurement object arranged in a laser light irradiation direction as a displacement amount in a laser light irradiation axis direction. It is composed of a laser oscillator 5a for irradiating while changing the intensity of the irradiating laser light with time, and a light receiving sensor 5b, and is measured by a triangulation method based on a phase difference of the intensity of the laser light reflected by the object to be measured. The distance L to the target is measured. The measured distance L is the distance L to the measurement work 8 below the measurement work 8, and a non-reflection error is detected at a position other than the measurement work 8.

Above the XY table 2, a frame 6 fixed as a structural part to each end of the surface plate 1 in the X-axis direction is provided.
A jig 7 for holding a work supported on the upper end of the work is arranged. The jig 7 has a holding part corresponding to the shape of each end when the concave side of the measurement work 8 is directed downward, and holds the measurement work 8 with the concave side down. The measurement work 8 is a kind of a standardized product group and is a lightweight (0.2 kg to 0.5 kg) resin molded product having a substantially container shape. Has dimensions. Note that the measurement work 8 has variations in which various dimensions are given in the length direction (the displacement direction of the X-axis actuator 3).
In order to cope with this variation, a slider that can be displaced in the length direction of the measurement work 8 (the displacement direction of the X-axis actuator 3) may be provided.

The XY table 2 and the laser displacement meter 5 are controlled by a computer 10 and auxiliary equipment. Hereinafter, the computer 10 and the auxiliary equipment will be described with reference to FIG. The computer 10 includes the arithmetic unit 1
1 (CPU), a storage device (memory) 12, and has an input device 13 such as a keyboard and a display device 14. In addition, as a peripheral device, an external storage device 1
5, a printer 16 and communication means 17 for data communication.

As equipment for signal transmission between the laser displacement meter 5 and the computer 10, a displacement (distance) signal obtained by measurement of the laser displacement meter 5 is converted to a DC voltage (for example, a voltage in the range of ± 5 V). ) And outputs the output voltage of the displacement meter amplifier 21 at a conversion speed of 5.
An A / D converter 22 that performs AD conversion to a digital signal in 00 μs, and a parallel interface 23 for individually controlling the actuators 3 and 4 of the XY table 2 are provided.

The computer 10 processes the displacement (distance) up to the measurement work 8 obtained by the laser displacement meter 5 while controlling the drive of the XY table 2 to perform a three-dimensional shape of the measurement work 8 to be measured. Is calculated as the measurement result of the measurement work 8. Here, a large number of measurement coordinates (i, j) arranged in a fine grid pattern are set for the positions of the X-axis and the Y-axis of the laser displacement meter 5 provided on the movable part of the XY table 2, and each measurement is performed. The distance L to the measurement work 8 corresponding to the coordinates (i, j) is measured, and X is defined as distance data D (i, j) corresponding to each measurement coordinate (i, j).
The measurement coordinate (i, j) on the Y table 2 is once stored and arranged in the storage device 12 together with the measurement coordinates (i, j). Calculate the shape.

Hereinafter, control of the XY table 2 and processing of the measurement data of the laser displacement meter 5 in the computer 10 will be described with reference to FIG. First, an initialization setting is performed according to a measurement start instruction (step 1).
Here, the position of each actuator in the XY table 2 is controlled to the initial position, the A / D converter is initialized, and the distance data D (i, j) and the like are cleared to zero.

Next, step feed is performed for the Y-axis actuator 4 (step 2), and scanning of the X-axis actuator 3 is started at that position (step 3). This X
When the axis actuator 3 scans, the measurement coordinates (i,
j), the measurement is successively performed by the laser displacement meter 5 and the distance data D (i, j) is stored in the storage device 1.
2 (Step 4), X-axis actuator 3
Scan until the end is reached.

When the scanning of the X-axis actuator 3 has been performed to the end (YES in step 5), the scanning of the X-axis actuator 3 ends (step 6), and if the step feed of the Y-axis actuator 4 has not reached the end (step 6). (NO in step 7), proceed to step 2 to perform step feed of the Y-axis actuator 4, and perform steps 3 to 6
Is repeated. Here, the forward path and the backward path are set as the scanning of the X-axis actuator 3, and as shown in FIG. 5, the forward path scanning and the backward path scanning are performed alternately so as to perform a reciprocating motion. Step feed by the Y-axis actuator 4 is performed.

If the step feed of the Y-axis actuator 4 has reached the end (YES in step 7), X
The drive control of the Y table 2 is completed, and thereafter, the process proceeds to processing of the distance data D (i, j).

In the processing of the distance data D (i, j), first, as preprocessing, the array of the distance data D (i, j) obtained by the backward scanning by the X-axis actuator 3 is arranged in the same array as the forward scanning. Data rearrangement is performed (step 8). Next, a smoothing process (filtering) of the distance data D (i, j) is performed (step 9).
Here, for each distance data D (i, j), a moving average is calculated using the distance data of four nearby points.

Next, an XY ridge line (contour shape) in the XY plane direction is extracted based on the gradient of the distance data D (i, j) in the XY plane direction (step 10). Further, the distance data D (i, j) on the XY ridge line extracted above is extracted to extract the XZ ridge line (step 11). Based on the above extraction results, the torsion and flatness of the measurement work 8 are calculated and the results are output (step 12).

Next, an example of a measurement result of the three-dimensional shape obtained by the above data processing will be described. FIG.
The schematic shape of the measurement work 8 is shown, where the lower side in the figure is the pipe side and the upper side in the figure is the opposite pipe side. FIG. 7 shows the result of extracting the XY ridge line (contour shape) in the XY plane direction for the measurement work 8 whose schematic shape is shown in FIG. 6, and FIG. 8 shows the result in the XY plane direction in FIG. It shows the result of extracting the ridge line in the XZ plane direction in the ridge line. FIG. 9 shows a result of synthesizing the measurement results of the XYZ contour shape based on the calculation results of these ridge lines.
In FIG. 9, A is a standard plane determined by three corner points o, p, and q, and B is an XYZ synthesized and displayed.
It is a contour shape. The calculation of the flatness error m and the torsion height n can be performed more easily with this device configuration.

As described above, in the present invention, X on the surface plate 1
Since the measurement work 8 is arranged above the Y table 2 and the laser beam is emitted upward from the laser displacement meter 5 of the movable part of the XY table 2 below the measurement work 8, the outer circumference of the measurement device is protected. There is no need to provide a guard, and it is not necessary to take any special measures for protection for the operator, and the three-dimensional shape can be measured with a simple configuration.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the appearance of a three-dimensional shape measuring apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a laser displacement meter of the present embodiment and a measurement principle thereof.

FIG. 3 is a block diagram showing a computer and peripheral devices for control calculation in the three-dimensional shape measuring apparatus of the present embodiment.

FIG. 4 is a flowchart illustrating a control operation of a computer in the three-dimensional shape measuring apparatus according to the present embodiment.

FIG. 5 is an explanatory diagram for explaining movement of a movable portion of an XY table in the three-dimensional shape measuring apparatus according to the embodiment.

FIG. 6 is an explanatory diagram showing a measurement work measured by the three-dimensional shape measuring apparatus of the present embodiment.

FIG. 7 is an XY ridgeline measurement diagram showing a calculation result in the XY plane direction by a computer in the three-dimensional shape measuring apparatus of the present embodiment.

FIG. 8 is a measurement diagram of an XZ ridgeline showing a calculation result in an XZ plane direction by a computer in the three-dimensional shape measuring apparatus of the present embodiment.

FIG. 9 is a composite display diagram of an XYZ contour shape of a measurement work showing measurement results by the computer of the present embodiment.

[Explanation of symbols]

2 XY table 5 Laser displacement meter 7 Jig (work holding means) 8 Measurement work (work) 10 Computer (shape calculation means, distance data storage means)

Claims (2)

(57) [Claims] 1. A three-dimensional shape measuring method for irradiating a work with laser light and measuring a three-dimensional shape of the work based on reflected light of the laser light, wherein a movable XY table mounted on a substantially horizontal plane is movable. It provided with only the laser displacement gauge which irradiates directed the laser beam upwardly parts, the workpiece held above said XY table by the work holding unit, measured by the laser displacement meter at each coordinate of the XY table And storing the calculated distance data to the work together with the coordinates and calculating a contour shape of the work based on the distance data. 2. A three-dimensional shape measuring apparatus for irradiating a work with laser light and measuring a three-dimensional shape of the work based on reflected light of the laser light, comprising: an XY table mounted on a substantially horizontal plane; the provided on the movable portion of an XY table, and a laser displacement gauge which irradiates with <br/> directed a laser beam upward, and the workpiece holding means for holding the positioning the workpiece above the XY table, the XY Distance data storage means for storing distance data to the work measured by the laser displacement meter at each coordinate of the table together with the respective coordinates, and the distance of the work based on the distance data stored in the distance data storage means. And a shape calculating means for calculating a three-dimensional shape , wherein the movable part of the XY table includes only the laser displacement meter.
A three-dimensional shape measuring apparatus, characterized in that a three-dimensional shape measuring device is provided .