JP3162749B2 - Welding line detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding line detecting device, and more particularly to a welding line detecting device suitable for detecting a welding line in automatic welding using an automatic welding machine or a welding robot.

[0002]

2. Description of the Related Art Conventionally, various types of optical welding line scanning sensors have been devised. In particular, sensors for specific applications such as welding of steel frames, structures for shipbuilding, and welding of automobile bodies have been put to practical use. I have.

[0003]

However, in such a conventional technique, since a sensor which can be widely applied to various joint shapes has not been put into practical use, welding to various joint shapes is required. In the field of sheet metal welding, its development is particularly awaited in order to automate welding.

An object of the present invention is to pay attention to such a conventional technique, and in sheet metal welding which is required to cope with various joint shapes, an automatic welding machine or an automatic welding machine using a welding robot is used. An object of the present invention is to provide a welding line detection device applicable to welding.

[0005]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides a floodlight that emits a light beam in a Y-axis direction orthogonal to a X-direction welding portion of a member to be welded; An area sensor for receiving reflected light from the member, first detection means for detecting a welding line based on the detection of the area sensor when there is a gap in the butted portion of the member to be welded, and detection of the area sensor Second detecting means for detecting a welding line when there is a backing material below the gap between the butted portions of the members to be welded, and a butting portion of the members to be welded based on the detection of the area sensor. A third detecting means for detecting a welding line when the gap is very narrow or in close contact, and a selector means for selecting the first, second or third detecting means. .

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a welding line detecting apparatus according to the present invention will be described below with reference to FIG. This welding line detection device uses light (visible light or infrared light) emitted from the light source 1.
A light projector 5 for projecting slit-shaped light L1 onto the surface of the member to be welded W through the lens 3, an area sensor 7 as a light receiving unit for receiving the reflected light L2 from the surface of the member to be welded W, A controller 9 for receiving the light receiving signal from the sensor 7 to detect the surface shape of the member W to be welded and to detect the welding line WL. This is a device for detecting the line WL.

The control section 9 has an A / D converter 11 for converting a light receiving signal into a digital quantity, a timing circuit 15 for storing the signal in a memory 13, and the like.

In such a welding line detecting device, the light emitting device 5
The slit-shaped light L1 emitted from the welding line WL in the X direction is Y
The reflected light L2 is received by the area sensor 7 via the lens 17 in a state of crossing at right angles to the direction. And
The area sensor 7 transmits a light receiving signal to the control unit 9. In the control section 9, after the A / D converter 11 receives the light receiving signal and converts it into a digital amount, the timing circuit 15 synchronizes the memory 1 with the transfer clock (not shown) of the area sensor 7 in the memory 1.
3 is stored.

Next, a method of detecting the welding line WL will be described with reference to the drawings. FIG. 2A shows a welding line detection device. The control unit 9 recognizes the cross-sectional shape of the workpiece W from the stored signal, as shown in FIG. That is, as shown in FIG. 2C, the peak position of the reflected light L2 for each scanning line corresponds to the cross-sectional shape at the position where the slit-shaped light L1 is projected. This position is detected for every scanning line to obtain the cross-sectional shape shown in FIG.

A method of detecting a welding line WL for each case in which the shape of the butted portion is different will be described below with reference to the drawings.

Detection Case 1 In case 1, as shown in FIG. 3A, a case where there is a gap G at the butted portion of the member W to be welded will be described. Thus, the gap G is formed at the butted portion of the member W to be welded.
In the case where there is, since there is no reflected light L2 from that portion, a notched portion g is generated in the cross-sectional shape obtained as shown in FIG. Therefore, the middle point Pa (xa, ya) of the two points P1 (x1, y1) and P2 (x2, y2) immediately before and after the missing portion g is regarded as the welding line WL position. Here, each coordinate of this midpoint Pa is xa = (x1 + x2) / 2, ya = (y1 + y2) /
2 For the sake of convenience in the following description, the means for detecting the welding line WL by the detection method in this case is referred to as “first method”.
Of the detecting means.

Detection Case 2 In case 2, as shown in FIG. 4 (A), a case where a backing material (including a jig) 19 and the like are provided below the gap G of the butted portion will be described. In this case, the change in the distance to the surface of the member to be welded W is a concave shape as shown in FIG. 4B, so that two points P3 (x3, y3) and P4 immediately before and after the concave are formed. The midpoint Pb (xb, yb) of (x4, y4) is regarded as the welding line WL position. Here, the coordinates of this midpoint Pb are
xb = (x1 + x2) / 2 and yb = (y1 + y2) / 2.

Then, two points P3 immediately before and after the depression,
To recognize P4, for example, the member to be welded W in the Y-axis direction
When the difference ΔY of the distance to the surface is taken, a graph similar to the shape shown in FIG. 4B is obtained as shown in FIG. 4C.
In this graph, points at which the difference value ΔY is maximum are defined as two points P3 and P4. That is, MAX [x (i) −x (i +
1)], x (i) may be x3 and MAX [x (i + 1) −x (i)] may be x4. For convenience in the following description,
The means for detecting the welding line WL by the detection method in this case is referred to as "second detecting means".

Detection Case 3 Next, as shown in FIG.
Is very narrow or absent.
In this case, as can be seen from FIG. 5B, there is no change in the characteristic shape. That is, since the gap G is too small to be in close contact, a change in the distance to the surface of the member W to be welded cannot be detected as shown in FIG. However, "burrs" and "burrs" are generated at the end of the member W to be welded at the time of cutting or the like, so that irregular reflection as shown in FIG. That is, since the reflectance of the light incident on the area sensor 7 is reduced, the brightness of the reflected light is as shown in FIG.
As shown in FIG. Therefore, the welding line WL can be recognized from the change in the brightness distribution.

Therefore, as shown in FIG. 6A, the lowest lightness position yc is obtained from the lightness distribution data, and a cross-sectional shape position xc corresponding to yc is obtained in the cross-sectional shape data. Thereby, the welding line WL position Pc (xc, yc) can be detected. For convenience in the following description, the means for detecting the welding line WL by the detection method in this case is referred to as “third detection means”.
Call.

Next, a processing procedure of the control unit 9 using the above-described detecting means will be described with reference to the drawings.

Processing Case 1 In this case, as shown in FIG. 7, the control unit 9 has a selector means SL, and determines which of the three detection means is used to detect the welding line WL or the like. , Can be selected by the operator according to the joint shape. That is, the member to be welded W is determined by the operator.
If there is a gap G at the butting portion, the first detecting means is selected. If there is a backing material (including a jig) 19 below the gap G at the butting portion, the second detecting means is selected. Select If the gap G between the butted portions is very small or not, the third detecting means is selected, and a detecting means suitable for each case is adopted. Here, the welding positions detected by these detecting means are given by Pa, Pb, and Pc, respectively, as described above.

This makes it possible to quickly detect the welding line WL and the like by utilizing the experience of the operator.

Processing case 2 In this case, as shown in FIG. 8, first, processing is performed by the first detecting means (step S21), and it is determined whether or not the welding line WL has been detected (step S22). . When the welding line WL is detected, Pa is output as the welding line WL position (step S23). On the other hand, when the welding line WL is not detected in step S22, the processing by the second detecting means is performed (step S2).
4) It is determined whether a welding line WL has been detected (step S25). When the welding line WL is detected, Pb is output as the welding line WL position (step S2).
6). On the other hand, if the welding line WL is not detected in step S25, the brightness distribution data of the cross-sectional shape is created (step S27), and the processing by the third detecting means is performed (step S28), and the position of the welding line WL is determined. As Pc
Is output (step S29).

As described above, the processing is performed when the detection processing of the welding line WL is easy, and the next detection processing is performed only when the detection of the welding line WL is not achieved, thereby saving processing time. Further, since there is no processing performed by the operator, it can be used for automatic welding.

Processing Case 3 In this case, as shown in FIG. 9, the detection processing by the first, second and third detection means is all performed in parallel, and the most appropriate welding line WL position is determined. To adopt. That is, the detection processing by the three detection means is performed in parallel, and the recognition evaluation value L set for each of these detection means is determined.
a, Lb, and Lc are calculated (Steps S31, S32, and S33). Then, these recognition evaluation values La, Lb, Lc
Are compared (step S34), and the processing result of the detecting means having the largest recognition evaluation value is adopted as the welding line WL position (step S35).

Here, in order to obtain the recognition evaluation values La, Lb, Lc in the respective detection processes, for example, they can be determined as follows.

In the case of the first detecting means, the size of the gap G at the butted portion is set as the evaluation value La, and if the gap G is small, the evaluation value La is set so as to decrease (see FIG. 3). For example, it can be set as in the following equation.

La = ka · [(x1-X2) ² + (y1-y2) ² ] ^1/2 Here, ka is a weighting coefficient.

In the case of the second detecting means, the magnitude of the difference value ΔY is used as the evaluation value Lb, and if the depression is small, the difference value ΔY becomes small, so that the evaluation value Lb is set to decrease (
(See FIG. 4). For example, it can be set as in the following equation.

Lb = kb · [max [x (i) −X (i + 1)] + max [X (i + 1) −x (i)]] Here, kb is a weight coefficient.

In the case of the third detecting means, the difference between the average value γ of the lightness distribution and the lightness γp at the lowest point of the lightness is obtained, and the evaluation value Lc is set to be lower if the lowest point is smaller. FIG. 6 (B)].

Lc = kc · [max (r-rp)] Here, kc is a weight coefficient.

With these La, Lb, and Lc as evaluation values,
If these values are equal to or greater than the required values, the detection of the welding line WL is successful, and if it is less than the required values, it is unsuccessful.

As described above, all the three detection means are processed in parallel, and the detection results obtained by comparing the detection results and adopting the best result are adopted as the welding line WL positions. Processing can be performed. In addition, since work and judgment by the operator are not required,
Suitable for detecting a welding line WL in automatic welding.

Next, another embodiment of the welding line detecting apparatus according to the present invention will be described with reference to FIG. Here, components common to those of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted. In this welding line detecting device, a light source 21 that emits a spot light, a light projecting mirror 25 and a light receiving mirror 27 that are reciprocated integrally by a motor 23, a line sensor 29
And a control unit 31. That is, the spot-like light (visible light or infrared light) L21 emitted from the light source 21 is irradiated by the motor 23 onto the light projecting mirror 25 which reciprocates in synchronization with the clock, and the reflected light L
22 is irradiated on the surface of the workpiece W. Therefore, light L
Numeral 22 reciprocates linearly on the surface of the member W to be welded. At this time, the welding line WL should cross the welding line WL as perpendicularly as possible. Then, the light L23 reflected on the surface of the workpiece W is received by the line sensor 29 via the light receiving mirror 27 which reciprocates in synchronization with the light projecting mirror 25. The line sensor 29 transmits a light receiving signal to the control unit 31.

Even when such a welding line detecting device is used, the welding line W is similarly formed by the procedure described in the above embodiment.
Since L and the like can be detected, a similar effect can be obtained.

In the above two embodiments, only the butt joint is used. However, other face joints, fillet joints and lap joints can be recognized.

The recognition evaluation value L in processing case 3
Although the equations for obtaining a, Lb, and Lc have been exemplified, the present invention is not limited to this, and various equations based on the same concept can be adopted.

[0035]

As can be understood from the above description of the embodiment, in short, the present invention is directed to the light beam (L1) in the Y-axis direction orthogonal to the X-direction welding portion of the member to be welded (W).
(5), an area sensor (7) for receiving the reflected light (L2) from the workpiece (W), and the workpiece ( First detecting means for detecting a welding line (WL) when there is a gap (G) in the butt portion of W), and a butt portion of the member to be welded (W) based on the detection of the area sensor (7); Second detecting means for detecting a welding line (WL) when there is a backing material (19) below the gap (G), and the member to be welded based on the detection of the area sensor (7). The third detecting means for detecting the welding line (WL) when the gap (G) of the abutting portion of W) is very narrow or in close contact, and the first, second or third detecting means And a selector means (SL) for selecting.

Therefore, according to the present invention, when the gap G is present at the butted portion of the members to be welded, when the backing material 19 is present in the gap G, and when the gap is in close contact with the welding line WL, Can be selected, and a welding line can be easily detected corresponding to various shapes of the butted portions of the members to be welded.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a welding line detection device according to the present invention.

FIG. 2A is an explanatory diagram showing an overall state detected by a welding line detection method according to the present invention. (B) is a figure which shows the surface shape of the to-be-welded member which the control part detected. (C) is a graph showing a state of light reflected from the member to be welded. (D) is a figure which shows the detected surface shape of the to-be-welded member.

FIG. 3A is an explanatory diagram showing a welding line detection method when a gap is present at a butt portion of a member to be welded. (B) is a figure which shows the surface shape of the to-be-welded member obtained by (A).

FIG. 4A is an explanatory diagram showing a welding line detection method when a backing material or the like is provided below a gap between butt portions of members to be welded; (B) is the surface shape of the member to be welded obtained in (A). (C) is a graph showing the difference in the distance to the surface of the member to be welded in (B).

FIG. 5A is an explanatory diagram showing a welding line detection state in a case where the gap between the butted portions of the members to be welded is very narrow or absent. (B) is a figure which shows the surface shape of the to-be-welded member obtained by (A).

FIG. 6A is a diagram showing the surface shape of the member to be welded obtained in FIG. 5A. (B) is a graph showing the brightness distribution on the surface of the member to be welded obtained in FIG. 5 (A). (C) is a sectional view showing a light reflection state of the butted portion.

FIG. 7 is a flowchart in a case where the control unit has selector means, and an operator selects a detecting means according to a welding shape to detect a welding line or the like;

FIG. 8 is a flowchart in a case where detection processing by three detection means is sequentially performed to detect a welding line WL and the like.

FIG. 9 is a flowchart in the case where detection processing by three detection means is performed in parallel, and the most appropriate welding line position is adopted among them.

FIG. 10 is a configuration diagram showing another embodiment of the welding line detection device according to the present invention.

[Explanation of symbols]

 1, 25 light source (light emitter) 7 area sensor (light receiving unit) 9, 31 control unit 29 line sensor (light receiving unit) G gap WL welding line W welded member

Claims (1)

(57) [Claims] 1. A light projector (5) for projecting a light beam (L1) in a Y-axis direction orthogonal to a welding portion in a X direction of a member to be welded (W), and a reflection from the member to be welded (W). Light (L
2) An area sensor (7) that receives light, and a welding line (WL) is detected based on the detection of the area sensor (7) when there is a gap (G) at the butted portion of the member to be welded (W). A first detecting means and a welding line (19) located under the gap (G) between the butted portions of the members to be welded (W) based on the detection of the area sensor (7). WL) for detecting when the gap (G) between the butted portions of the members to be welded (W) is very narrow or in close contact with each other based on the detection of the area sensor (7). A welding line detecting device comprising: a third detecting unit that detects a welding line (WL); and a selector unit (SL) that selects the first, second, or third detecting unit.