JPS6039964B2 - Welding groove center position detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a weld joint center position detection device.

In automating welding, it is very important to accurately detect the center position of a welding groove (hereinafter simply referred to as groove).

This is particularly important when performing multilayer welding.
Therefore, various groove center position detection devices have been proposed and put into practice. As a device for detecting the center position of a groove in a secondary groove, there is a device described in Japanese Patent Laid-Open No. 13305/1983.

This groove center position detection device includes an optical device that irradiates a groove portion with slit light, an imaging device that captures a slit image showing a cross-sectional shape of the groove by the slit light, and a slit image captured by the imaging device. a coordinate extraction device that extracts the coordinates of necessary slit image data from among the slit image data stored in the storage device; and an estimating device for estimating the position.The estimating device linearly approximates the slit image data of the groove hypotenuse portion by the method of least squares, and the intersection thereof is set as the groove center position. However, the conventional groove center position detection device described above has various problems as described below.

■ The groove surface is precisely machined to prevent weld defects.

Therefore, the slit image captured by the imaging device includes an unnecessary reflected image due to multiple reflections of the slit light on the junction surface. Furthermore, the S/N of the slit image on the oblique side of the groove is significantly reduced due to the arc light transmitted through the groove surface. Due to these causes, as a result of incorrectly detecting the oblique side of the function, the accuracy of detecting the center position of the function decreases. ■ In the latter half of multilayer welding, the slit image data of the oblique side of the joint becomes very small, resulting in a decrease in the accuracy of linear approximation and a decrease in the detection accuracy of the groove center position.

■ The slit image captured by the Shigo device is
Images are stored in a storage device, which typically requires large amounts of memory, making the device expensive and complex.

This invention was made in order to solve the various problems of the conventional groove center position detection device as described above. The feature is that the slit image data from the center of the Kansai to the hypotenuse of the Kansai is not used, but the slit image data at the horizontal part and the upper end of the hypotenuse of the Kansai are used to detect the center of the Kansai. have

The present invention will be explained by way of examples with reference to the drawings.

FIG. 1 is a schematic configuration diagram of a target center position detecting device according to an embodiment of the present invention. In the drawings, 1 indicates a welding base material 2,
This is an optical device that irradiates slit light 4 to three parts of two weld joints (hereinafter simply referred to as joints).

Reference numeral 5 denotes an imaging device that captures a slit image 4' showing the cross-sectional shape of the groove by slit light 4 irradiated onto the joint 3 from directly above the welding grooves 2, 2.

Reference numeral 6 denotes an image capture control circuit that captures (samples) only one line of slit image data from among the slit image signals from the imaging device 5, as will be described later.

The slit image data captured by the image capturing control circuit 6 is sequentially captured by a command from a main control circuit (not shown). 7 is an image capture control circuit 6
This is an image vertical one line storage circuit that stores one vertical line of slit image data taken in by.

Reference numeral 8 denotes a brightest point detection circuit that detects the upper layer of the slit image 4' from the slit image data stored in the image vertical one line storage circuit 7 and stores it. In order to smooth the slit image data, some slit position detection data are stored.

9 is a smoothing differentiation circuit that smoothes and differentiates some slit position detection data from the brightest point detection circuit 8.

10' is a shoulder determination circuit that determines and detects the shoulder of the slit image 4' based on the smoothed differential value calculated by the smoothed differential circuit 9.

11' is a joint center position calculation circuit that calculates the center position of the joint based on the shoulder signal of the IJ shot image detected by the shoulder determination circuit.

Reference numeral 12 denotes a welding torch drive control calculation circuit that calculates the required movement amount of the welding torch 14 based on the calculation result calculated by the groove center position calculation circuit 11.

Reference numeral 13 denotes a welding torch drive device that moves the welding torch (i) based on the calculation results calculated by the welding torch drive control calculation circuit (12).

Since the welding groove position detecting device of the present invention is configured as described above, the slit light 4 irradiated from the optical device 1 to the groove 3 section allows the ``groove cross-sectional shape to be detected at the groove 3 section''. A slit image 4' as shown is formed.

The slit image turtle' is captured as a green image by the imaging device 5. This slit image, as shown in FIG.
The image capture control circuit 6 receives a command from the main control circuit (not shown) to capture the slit image 4'' as shown in Fig. 2. One vertical line of slit image data at the coordinates xi located inside the left edge of the slit image 4'' by w2, which corresponds to about 1'3 in the horizontal part, is extracted from the slit image signal from the imaging device 5. Take in. The captured slit image data of one vertical line is stored in the image vertical one line storage circuit 7. The brightest point detection circuit 8 uses the slit image data A in FIG.
The y-coordinate position yi of the point is detected as the brightest point and stored.
Next, in accordance with the command from the pre-receiver control circuit, the image capture control circuit 6 advances the x-coordinate of the slit image data to be captured by one to capture xM, which is one vertical line of slit image data. It is stored in the line storage circuit 7. The technical point detection circuit 8 detects the brightest point based on the slit image data of one vertical line. In this detection, the slit image 4 is centered at the previously detected and stored y-coordinate position yi. Medium d, which is about three times the medium △d of ″
The brightest point is detected only between (see Figure 2). In this manner, when the brightest point detection circuit 8 tracks and detects the slit image 4'', by providing a limited range in which unnecessary light does not exist, it is possible to prevent the slit image 4' from being detected.

After some slit position detection data, that is, slit image data necessary for smoothing differential calculation described later, is obtained in the above manner, the smoothing differentiation circuit 9 smoothes and differentiates the slit position detection data. , emphasize the point of inflection that corresponds to the shoulder of the guansen.

The smoothing differentiation in the smoothing differentiation circuit 9 will be explained below.

FIG. 4A shows a line diagram representing the slit image 4' detected by the brightest point detection circuit 8, and the smoothed differential value dyj/■ at a certain x-coordinate xj is the same as the slit image 4' detected by the brightest point detection circuit 8. yk-i hand 2ykl. ．． ．． ．． ．． SenK is expressed as i+1.

The horizontal line figure of the detected slit image 4' fluctuates because the brightness distribution in the middle direction is non-uniform.

However, as is clear from equation {1}, since smoothing is added to the differential operation, the 3rd function
Only the shoulders of the person are emphasized. Therefore, the influence of the rocking of the horizontal portion is eliminated, and the detection accuracy when determining the shoulder of the joint 3 is improved. Next, to determine the shoulder of groove 3,
Depending on the imaging conditions, groove length, groove angle, etc., a value of about half of the differential value of the groove hypotenuse that can be calculated in advance is set as the value @(
(see FIG. 4B), and the shoulder judgment circuit 1 determines the magnitude of this and the calculation result dy/dx calculated by the smoothing differentiation circuit 9.
Compare by 0.

If dy/dx is less than 8, it is determined that the area is still in the horizontal region, and the image capture control circuit 6 captures the slit image data at the further x coordinate, and repeats the above-mentioned series of operations. . On the other hand, when dy/dx exceeds @, it is determined and detected as the left shoulder of the groove 3, which is indicated by the dotted point S in FIG.

After detecting the left shoulder, the main control circuit (not shown) sends a command to move to the right horizontal section, and this time, starting from the coordinates indicated by xm in FIG. By repeating the same operation as in Figure 2, point 3 is shown as SR point.
Detects the right shoulder of Next, when the SL point and the SR point on both shoulders of the joint 3 are detected, the center position of the S point and the SR point is calculated by the joint center position calculation circuit 11.

(Point P in Fig. 4 B) Since the groove center position has been calculated, welding torch drive control calculation circuit 1
2, the required movement amount of the welding torch 14 is calculated, and based on the calculation result, the welding torch 14 is moved to the joint center position by the welding torch drive device 13.

As shown in FIG. 5, by attaching the slit light conversion lens 15 to the optical device 1 via the optical fiber 16 and attaching the objective lens 17 to the imaging device layer 5 via the optical fiber 18, Even in a very narrow space, the device of the present invention makes it possible to automatically weld by always aligning the welding torch with the groove.

As explained above, according to the present invention, the center position of the joint is detected based only on the slit image data of the horizontal part of the slit image data. Not affected by light. As a result, in multilayer welding, for example, even if the cross-sectional shape is as shown by line C in Figure 4, the groove center position can be detected with high accuracy. Since it is only necessary to store one line of slit image data, useful effects such as the ability to reduce the cost and size of the image storage device are brought about.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram of a welding groove center position detection device according to an embodiment of the present invention, Fig. 2 is an explanatory diagram showing the fluctuation of the brightest point of a slit image, and Fig. 3 is a slit image data FIGS. 4A and 4B are explanatory diagrams showing a shoulder determination method using smoothing differential calculation, and FIG. 5 is a perspective view of a main part of another embodiment. In the drawing, 1...optical pupil "2...
...Weld mother village, 3...Weld groove, 4...Slit light, 4'...Slit image, 5...
...Imaging device, 6...Image capture control circuit, 4''
... Slit image, 7 ... Image vertical 1 line storage circuit, 8 ... Brightest point detection circuit, 9 ... Smoothing differentiation circuit, 10 ... Shoulder judgment Circuit, 11...
... Welding torch drive control calculation circuit, 13 ... Welding torch drive layer, 1
4... Welding torch, 15... Slit light conversion lens, 16... Optical fiber, 17...
...Objective lens, 18...Optical fiber. Plan ↑Figure 2Figure 3Figure 4Figure 5

Claims (1)

[Claims] 1: an optical device that irradiates a welding groove portion of a welding base material with slit light; an imaging device that captures a slit image showing a cross-sectional shape of the groove by the slit light; an image capture control circuit that captures only one line of slit image data; an image vertical one-line storage circuit that stores one vertical line of slit image data captured by the image capture control circuit;
a brightest point detection circuit that detects and stores the position of the slit image on the image from the slit image data written in the image vertical one line storage circuit; and a brightest point detection circuit that smoothes the slit image data detected by the brightest point detection circuit. a shoulder determination circuit that determines and detects the shoulder of the slit image based on the calculation result calculated by the smoothing differentiation circuit; A welding groove center position detection device comprising: a groove center position calculation circuit that calculates the center position of the welding groove based on a signal.