JPH0218674B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a welding arc position control device, and particularly to a welding arc position control device that controls the welding torch position by monitoring the arc during welding and the shape of the welded part (hereinafter referred to as base metal). The present invention relates to a welding arc position control device that controls position.

[Background of the invention]

2. Description of the Related Art Conventionally known weld line detection devices using optical systems include those shown in FIGS. 1 and 2. In the example shown in Fig. 1, a slit-shaped laser beam is obliquely irradiated onto the groove surface 3 of the base material 2 from a light projection means 1 using a laser beam, and the reflected light from the groove surface 3 is captured by a solid-state camera. In this method, the welding position is determined by detecting the welding position with a light receiving means 4 such as the above, and analyzing the image obtained at this time. In this method, the groove surface 3 is copied once before welding, and the groove information is stored in an external storage means, and the welding torch 5 is controlled based on this information during welding, and the welding wire 6 is supplied with electric power. In some cases, the position of the torch 5 is controlled by tracing the groove surface 3 while supplying the arc 7 and generating the arc 7. However, since neither method directly observes the tip of the wire during welding, it is not possible to detect bends in the wire or changes in the amount of wire protrusion, so the torch must accurately follow the welding line. I can't. On the other hand, FIG. 2 shows a method in which the arc 7 during welding is captured through a filter group 8 into a light receiving means such as an ITV camera, and the obtained image is analyzed to determine the arc occurrence position at the tip of the wire. However, with this method, it is difficult to set the level of the observation system due to large changes in the intensity of the arc light, and since the arc itself is used as a light source, it is difficult to detect the groove shape around the arc because it is affected by the brightness of the arc. There were problems such as:
Although such drawbacks can be solved by using an optical system having both of FIG. 1 and FIG. 2, the apparatus becomes large and complicated, which is not preferable in practice.

[Purpose of the invention]

The purpose of the present invention is to accurately detect the relationship between the wire tip position and the groove position during welding, and automatically move the welding arc to a predetermined groove position regardless of bending of the welding wire or changes in the amount of protrusion. It is an object of the present invention to provide a welding arc position control device with a simple configuration that can be controlled.

[Summary of the invention]

The present invention provides a light projecting means for irradiating light onto a groove at a position preceding the position of a welding arc, and a single light receiving means for receiving both reflected light from the groove and light from the welding arc. a filter that attenuates the welding arc light incident on the light receiving means; an image processing device that calculates a groove shape and a welding arc position from the groove image and the arc image obtained by the light receiving means, respectively; Based on the groove shape information and welding arc position information obtained by the image processing device,
a welding torch position control device that controls the position of the welding torch to control the position of the welding arc to a predetermined groove position; The filter is placed in a position within the field of view, and the filter is placed between the welding arc and the light receiving means,
The light projecting means is a welding arc position control device arranged so that the reflected light does not pass through the filter and illuminates the groove at a position where it can enter the light receiving means.

With this configuration, according to the present invention, the object of the present invention can be achieved through the following actions.

That is, since a groove image at a position preceding the arc position is detected, a groove image that is less susceptible to the influence of arc light can be obtained. This makes it possible to accurately detect the groove shape regardless of changes in the intensity of the arc light. Furthermore, since the welding arc image is also detected, changes in the bending of the wire, etc. can be accurately detected based on the welding arc image. Therefore, the arc position can be accurately and automatically controlled to a predetermined groove position.

In addition, the configuration of the device is simplified because the positional relationship between the light receiving means, the irradiation position of the groove, and the welding arc position is defined so that a welding arc image and a groove image are obtained by a single light receiving means. , the above effects can be achieved without increasing the size. Furthermore, when obtaining two images with one light receiving means, it is desirable to make their received light intensities almost the same.
In relation to the above arrangement, only the welding arc light is attenuated by the filter.

[Embodiments of the invention]

An embodiment of the present invention will be described below. FIG. 3 shows the configuration and principle of a welding arc position control device according to the present invention. In Fig. 3, 9 is a half mirror with low transmittance and high reflectance.
The arc image P' at the arc detection point P is captured by the image sensor 10 via the half mirror 9. On the other hand, at the same time, the light is projected onto the groove surface 3 by a light projecting means 11 such as a semiconductor laser device. A groove image Q' at a position Q preceding the arc detection point P is similarly reflected by the half mirror 9 and taken into the image sensor 10. The half mirror 9, the image sensor 10 and the semiconductor laser device 11 form a visual sensor detection unit 1.
2 are configured. As shown in FIG. 5, the image obtained by the image sensor 10 is such that an arc image P' and a groove image Q' are formed at different positions. These images are separated by an image separation device 13 by noise removal, thin line removal, image subtraction processing, etc., and then separated by an image processing device 14.
be taken in. The image processing device 14 includes a groove image processing section 15 and an arc image processing section 16. The groove image processing unit 15 processes the groove image
The type of groove is determined from Q' by pattern matching, for example, and then the necessary information regarding the groove shape is calculated, converted to a coordinate position as seen from the robot system, and output. On the other hand, the arc image processing section 16 determines the arc point or the amount of wire protrusion from the arc image P', and outputs these as arc position information.

The groove shape information obtained by the groove image processing section 15 is delayed by a certain amount in a delay processing section 17, and then transmitted to a robot control device 18 and a welding machine control device 19 that constitute a welding torch position control device. Ru. The delay processing unit 17 matches the time axis of the temporally preceding groove shape information with the time axis of arc position control. Based on the groove shape information and arc position information processed in this way, the robot controller 18 controls the welding torch 5 so that the position of the welding arc follows the predetermined groove position, that is, the welding line.
It is now possible to control the position of the Thereby, the welding arc position can be precisely controlled in accordance with the accurately detected groove shape information and in response to changes in the bending of the wire. Similarly, the welding machine control device 19 controls the welding current and arc voltage based on the same groove and arc information. In this way, according to this embodiment, 1
In addition to being able to capture arc images and groove images using the image sensor, the groove information of areas that are less affected by arc light is used through delay processing, which eliminates problems with equipment in the past. This solves the difficulty of setting the level of the observation system due to increase in size or changes in arc light intensity, making it particularly suitable for fully automatic welding robots. FIG. 4 shows an embodiment in which the visual sensor detection section 12 of FIG. 3 is applied to a welding robot. An image sensor 21 provided in a welding robot 20 is connected to a base material 2 using a cylindrical lens 23 from a semiconductor laser generator 22.
The groove image projected onto the groove surface in a fan shape and then reflected by the half mirror 25 and the half mirror 25
It is possible to simultaneously capture an arc image that enters through a spatter prevention net 26 and dust prevention air 27 provided on the front surface (welding torch side) of the welding torch.

As described above, the welding arc position control device of the present invention is compact and highly functional, so it is ideal for fully automatic welding robots as described above.

Furthermore, the configuration as shown in FIG. 3 makes it possible to detect the starting and ending ends of the welding line, thereby realizing a highly functional welding robot.

Furthermore, a method may be used in which the arc image and the groove image are simultaneously captured on the same image sensor without using a half mirror. For example, as shown in FIG. 6, the image sensor 10 is arranged so that the light of the welding arc is captured through the filter group 8 instead of the half mirror, and the groove is irradiated with laser light by the semiconductor laser device 11. This can be realized by arranging the image sensor 10 so that the reflected light from the surface 3 is captured in the image sensor 10.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to simultaneously capture an arc image and a groove image using one light receiving means, and therefore, there is an effect that the weight of the detection device can be reduced. Furthermore, since the groove shape at the location preceding the arc light is detected in advance, highly accurate automatic welding can be performed without being affected by the arc light, and welding quality can be improved.

[Brief explanation of drawings]

1 and 2 are diagrams showing a welding line detection device using a conventional optical system, FIG. 3 is a diagram showing the configuration and principle of a welding arc position control device according to the present invention, and FIG. 4 is a diagram showing a welding line detection device using a conventional optical system. FIG. 5 is a diagram showing an example of an image formed on the image sensor 10, and FIG. 6 is a diagram showing the main part of an embodiment that does not use a half mirror. be. 9...Half mirror, 10...Image sensor, 1
1... Semiconductor laser device, 12... Visual sensor detection section, 13... Image separation device, 14... Image processing device,
15... Groove image processing section, 16... Arc image processing section, 17... Delay processing section, 18... Robot control device.

Claims (1)

[Scope of Claims] 1. A light projector that irradiates light onto a groove at a position preceding the position of the welding arc, and one unit that receives both the light reflected from the groove and the light of the welding arc. a light receiving means, a filter that attenuates the welding arc light incident on the light receiving means, and an image processing device that determines a groove shape and a welding arc position from a groove image and an arc image obtained by the light receiving means, respectively. and a welding torch position control device that controls the position of the welding torch to a predetermined groove position by controlling the position of the welding torch based on the groove shape information and welding arc position information obtained by the image processing device. The light receiving means is disposed at a position where the groove portion irradiated with the light and the welding arc are within its field of view, and the filter is disposed between the welding arc and the light receiving means, A welding arc position control device, wherein the light projecting means is arranged so that the reflected light does not pass through the filter and illuminates a groove portion at a position where the reflected light can enter the light receiving means. 2. The filter is a half mirror, the light of the welding arc passes through the half mirror and enters the light receiving means, and the reflected light from the groove is reflected by the half mirror and enters the light receiving means. A welding arc position control device according to claim 1, characterized in that the welding arc position control device has a configuration in which: 3 The groove image signal and the arc image signal detected by the light receiving means are each separated by an image separating means and inputted to the image processing device, and the groove shape information output from the image processing device is The welding arc position control device according to claim 1, wherein the welding arc position control device is configured to be inputted to the welding torch position control device after a delay.