JPH0679779B2 - Shape recognition method for corner joints - Google Patents

Description

TECHNICAL FIELD The present invention relates to a shape recognition method for a corner joint for optimally controlling welding conditions.

(Prior Art) Conventionally, a system for recognizing the shape of a welded joint portion during welding and optimally controlling welding conditions such as a torch position, a filler supply amount, and a welding current based on the obtained results, for example, Proposals such as JP-A-59-28608 and JP-A-61-4907 have been made.

In particular, a typical system for recognizing the shape of the joint to optimally control the welding conditions has a configuration shown in FIG. In the figure, 11 is a plate material to be measured, and the light emitted from a light source 12 such as a semiconductor laser is introduced into a projection scanning mechanism 16 through a lens 14 at a lap joint portion of the plate material 11 and the projected light is projected. The light is emitted as light having a constant cycle by a vibrating mirror or the like of the light scanning mechanism 16. Then, the reflected light is imaged on a light receiving element 13 such as a photodiode array or a CCD linear array via a light receiving lens 15 installed in a direction having a constant angle θ with the projection axis. .

In this way, the distance to the object surface can be obtained from the projection angle and the light receiving position by a simple geometrical operation (the same principle as triangulation). In order to carry out the measurement without being affected by the arc light during welding, various measures have been taken such as using modulated light for the laser light used for the measurement and providing a narrow band filter in front of the light receiving element.

(Problems to be Solved by the Invention) However, in the above-described method, since the reflected light of the spot light projected from the light projecting system is captured and measured by the light receiving system, the surface shape, property, color, etc. of the measurement target It is susceptible to influence, and particularly in the case of the shape of the corner joint shown in FIG. 7, it is difficult to perform stable measurement because the amount of received light fluctuates extremely. In order to solve this problem, various measures have been taken such as increasing the dynamic range of the light receiving element and controlling the intensity of the projection laser, but none of them can reliably detect the shape of the corner joint.

The present invention has been made in view of the above circumstances, and an object thereof is to make it difficult to be influenced by the surface shape, property, color and the like of a measurement object, and to detect stably and accurately even a shape such as a corner joint. We are trying to propose a method for recognizing the shape of a corner joint.

[Means for Solving the Problems]

In order to achieve the above object, the method for recognizing the shape of a corner joint according to the present invention determines the shape of the corner joint by using a scanning distance sensor of a triangulation distance measuring method including a pair of light emitting and receiving elements in a fixed positional relationship. At the time of detection, a first distance sensor A is provided at a position facing at least one surface of at least one of the two plate members forming the joint, and a first distance sensor A is provided at a position facing the other surface of the other side. It is characterized in that the shape data of the corner joint portion is recognized by combining and calculating the detection data of the second distance sensor B.

(Operation) Since the light emitting / receiving element is provided at a position directly facing one surface of the corner joint portion as described above, a stable light amount can be obtained from the joint portion and distance data can be accurately calculated. Since such a light projecting / receiving element is directly faced to the other one side surface, the shape of the corner joint portion can be recognized by calculating the distance data of both side surfaces adjacent to the corner joint portion.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

Figure 1 shows the shape of the corner joint and the dimensions of the joint required for welding control. In the figure, reference numerals 1 and 2 denote plate materials, and the plate materials 1 and 2 are in close contact with the end surface of one plate material (here, 1) on the rear surface side of the other plate material 2 and are combined at right angles to each other to form a corner portion. It is a thing. Then, a slight space is created at the corner between the plate material 1 and the plate material 2 to form a "gap". The difference between the surface of the plate material 1 and the end surface of the plate material 2 is “step”, the distance between the ridgeline of the surface of the plate material 1 and the ridgeline of the surface of the plate material 2 is “space”, and the edge line of the end surface of the plate material 2 is close to the plate material 1. Those who do are called "positions".

Among these names, the dimension data of "step" and "gap" are used to determine the welding current, the amount of filler supply, the torch posture, etc., and the data of "interval" and "position" are the torch position. Is used to determine

FIG. 2 shows the position of the light emitting / receiving element with respect to the corner joint. In the figure, the plate materials 1 and 2 are combined with each other in a right angle direction as a corner joint, and when placed at the α position on the extension of the bisector of the right angle direction (direction facing the corner joint), the plate material 1 is Since it becomes difficult to obtain the reflected light from the surface portions (portions with diagonal lines) of 2 and 2, it becomes difficult to detect the shape data of the corner joint portion.

Therefore, a position γ facing one surface of the plate member 1 forming the corner joint and a position β facing one surface of the plate member 2
It can be said that and are the optimum positions in terms of the amount of reflected light.

FIG. 3 shows the relationship between the received light amount obtained by the detection head and the calculated data Z in the case of the lap joint and the corner joint. In the case of a shape such as the lap joint shown in FIG. 3 (a), if the direction perpendicular to the light irradiation direction is x and the light irradiation direction is Z, the surface of the object is the light emitting / receiving surface of the detection head. Because of the positional relationship directly facing the portion, a stable light receiving amount can be obtained over the entire scanning range. Therefore, the calculated distance data also corresponds to the shape.

In the corner joint shown in FIG. 3 (b), the amount of light received from the surface of the plate material cannot be stably obtained in the direction directly facing the above-mentioned corner joint, so that the distance data corresponding to the shape cannot be obtained.

In the corner joint shown in FIG. 3 (c), the detection head 3 should be installed at a position facing at least one of the surfaces, that is, at a position facing the surface of the plate material 2 and including the joint part in its scanning area in the figure. Thus, the reflected light from the surface of the plate material 1 disappears, and the reflected light amount data and the distance data are shown in FIG. 5 (c).
As shown in the figure on the right side of FIG. 1, a stable light amount can be obtained from the joint portion, distance data can be accurately calculated, and shape data can be detected.

However, actually, as shown in FIG. 4, secondary reflection or tertiary reflection occurs due to the step of the joint, the variation of the clearance dimension, the cross-sectional shape, etc., or the amount of reflected light is obtained by the blind spot during projection. However, the reflected light amount data and the distance data differ between the stable region and the unstable region as shown in the figure.
The stable region is when the surface of the plate 2 is detected, and the unstable region is when the end of the surface is passed. Therefore, it is possible to detect the position of the end surface of the plate material which is directly facing by detecting the point where the amount of received light becomes unstable, and the distance data at that position indicates the distance data of the end surface of the plate material.

From this point of view, as shown in FIG. 5, the first distance sensor A is installed at a position directly facing the surface of at least one of the two plate members 1 and 2 constituting the corner joint, and the other surface is directly opposed. The second distance sensor B is installed at the position. If the set position coordinates of the two distance sensors A and B are measured by another means, the coordinates of the points a and b at the end of the facing plate member can be detected by the two distance sensors A and B. . Then, the obtained spatial coordinates of the two points a and b can be easily calculated from the set position coordinates of the distance sensors A and B.

The shape data of the joint portion is calculated from these two point coordinates a and b. At this time, in order to obtain the clearance dimension, it is sufficient to know the plate thickness dimension of the target plate material in advance. In the case of welding, since the plate thickness of the plate material is often limited to the initially set thickness, this does not impede the practice of the present invention.

(Effects of the Invention) As described above, the method for recognizing the shape of the corner joint of the present invention is
When detecting the shape of a corner joint using a triangulation type scanning distance sensor equipped with a pair of light emitting and receiving elements in a fixed positional relationship, at least one of the two plate materials constituting the joint is used. Computation is performed by combining detection data of the first distance sensor A provided at a position directly facing the surface on one side and the second distance sensor B provided at a position directly facing the surface on the other side. As a result, since the shape data of the corner joint portion is recognized, the shape of the corner joint portion can be detected stably and accurately without being affected by the surface shape, property, color, etc. of the measurement target. There are advantages.

[Brief description of drawings]

FIG. 1 is a perspective view of a main portion of a corner joint portion, FIG. 2 is a layout view of a distance sensor for detecting the corner joint portion, and FIG. 3 (a) is a reflected light amount data and distance data chart of a lap joint, and FIG. Figure (b) shows the amount of reflected light data and distance data at the detection position directly facing the corner of the corner joint, and Figure 3 (c) shows the reflection at the detection position directly facing one surface of the corner joint. Light intensity data and distance data diagram,
FIG. 4 is a detailed view of FIG. 3 (c) and this reflected light amount data and distance data diagram, FIG. 5 is a layout diagram in which distance sensors A and B are arranged at positions directly facing the corner joint, and FIG. 6 is a conventional example. FIG. 7 is a layout diagram of shape detection in the lap joint of FIG. 7, and FIG. 7 is a layout diagram of shape detection in the conventional corner joint. 1, 2 ... Plate material A ... First distance sensor B ... Second distance sensor

Claims (1)

[Claims] 1. A plate member for forming a joint when detecting the shape of a corner joint by using a scanning distance sensor of a triangulation distance measuring method having a pair of light emitting and receiving elements in a fixed positional relationship. Of the first distance sensor A provided at a position directly facing the surface of at least one of the two, and the detection data of the second distance sensor B provided at a position directly facing the surface of the other one of A method for recognizing the shape of a corner joint, characterized in that the shape data of the corner joint is recognized by performing the following calculation.