JPH0632861B2 - Welding robot equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a welding robot apparatus, and more particularly to a welding robot apparatus capable of continuously and automatically welding a work including a valley corner at an inner circumference.

"Prior art and problems" When performing horizontal fillet welding with a conventional welding robot apparatus, arc tracing control is usually performed to correct the deviation between the taught welding line and the actual welding line of the workpiece. .

However, if the work has a valley corner, the work deviation in the direction of the welding line cannot be detected, so the torch hits the wall of the corner or bends before reaching the corner, and proper welding cannot be performed.

This is because, at some point, this condition is no longer satisfied at the valley corner.

Therefore, if the work includes a valley corner, the welding line up to just before the valley corner and the welding line just after the valley corner are welded by a welding robot device, and the valley corner part is Welding is performed by work.

However, interposing such a manual welding process reduces the significance of using the welding robot apparatus by half.

[Object of the Invention] An object of the present invention is to provide a welding robot apparatus capable of continuously performing automatic welding inward even in the case of a work including a valley corner.

"Structure of the Invention" The welding robot apparatus of the present invention includes a first welding line from the starting point to the valley bending point, welding conditions related to the first welding line, and a first welding line from the valley bending point to the ending point. No. 2 welding line and condition setting means for setting welding conditions related to the second welding line, and second starting point setting for setting a second starting point located in the vicinity of the valley bending point and on the end point side of the valley bending point. First welding operation control means for advancing a welding operation in the first welding line direction under the welding conditions related to the first welding line while performing weaving and detecting the welding current or voltage, the welding current or voltage Detecting a predetermined change in Detecting a valley corner of a work by detecting a valley corner, a cornering control means for moving the welding torch to the second starting point after detecting the valley corner, and a moving to the second starting point After the second A second welding work control means for advancing the welding work in the welding line direction under the welding conditions relating to the second welding line is provided, and it is possible to continuously and automatically weld the work including the valley corner at the inner circumference. It is a feature of the above.

Further, the welding robot apparatus of the present invention includes a first welding line from the starting point to the valley bending point, welding conditions related to the first welding line, and second welding from the valley bending point to the ending point. Condition setting means for setting welding conditions relating to a line and its second welding line, second starting point setting means for setting a second starting point located in the vicinity of the valley break point and on the end point side of the valley break point, and weaving And a welding current or voltage is detected while advancing the welding operation in the first welding line direction under the welding conditions relating to the first welding line, and a predetermined welding current or voltage. A valley break corner detecting means for detecting a valley break corner of a work by detecting a change, after detecting the valley break corner, a welding current smaller than a welding current in a welding condition relating to the first welding line and a welding torch angle, Welding related to the first welding line Cornering control means for smoothly and continuously changing the welding torch angle under the welding condition of the second welding line to the welding torch angle for the second welding line and moving the welding torch to the second starting point, and the second starting point. The second welding work control means for advancing the welding work in the second welding line direction under the welding conditions relating to the second welding line after moving to It is a structural feature that automatic welding is possible.

[Examples] Hereinafter, the present invention will be described in more detail based on the examples shown in the drawings. Here, FIG. 1 is a block diagram showing the construction of a welding robot apparatus according to an embodiment of the present invention, FIG. 2 is a perspective view of an example of a work including a valley corner, and FIG. 3 is an operation of the apparatus shown in FIG. FIG. 4 is a schematic diagram of the movement locus of the welding torch by the apparatus shown in FIG. The present invention is not limited to the embodiments shown in the drawings.

In the welding robot apparatus 1 shown in FIG.
Supplies a drive signal to the robot body 4 via the servo circuit 3 so as to perform a movement in the welding line direction and a weaving movement perpendicular to the movement direction. Further, the work W is welded by electrically controlling the welding torch 6 via the welding machine 5. Further, the welding current is detected via the arc sensor 7. Furthermore, the operator's instruction is read via the control panel 8.

The control device 2 is configured with a computer as a center, and includes a condition setting unit 10, a near point setting unit 11, and a second point.
It has a starting point setting unit 12, a valley corner detecting unit 13, a first welding work control unit 14, a nearby welding work control unit 15, a cornering control unit 16 and a second welding work control unit 17.

Next, referring to FIGS. 3 and 4, the welding robot apparatus 1 will be described in the order of its operation. For convenience of explanation, in the work W as shown in FIG. 2, the starting point P ₁
→ We consider the work of welding in the order of valley break point P ₂ → end point P ₃ .

First, the operator inputs the start point P ₁ , the valley break point P ₂ , and the end point P ₃ via the control panel 8. As shown in FIG.
These points are the taught start point TP ₁ , mountain break point TP ₂ and end point.
It is set in the condition setting unit 10 as TP ₃ . Accordingly, the control device 2 recognizes the first welding line L ₁ between the starting point TP ₁ and the valley bending point TP ₂ , and the second welding line L ₂ between the valley bending point TP ₁ and the end point TP _3. Recognize that.

Further, the operator inputs the welding conditions for the first welding line L ₁ and the welding conditions for the second welding line L ₂ .

As a specific example of this welding condition, for example, a welding current of 25
0A, welding speed 24 cm / min, weaving width 10 mm, weaving frequency 2 Hz, etc. However, the present invention is not limited to this, and for example, a welding current of 70 to 500 A and a welding speed of 1 to
It can be appropriately selected within the range of 200 cm / min and the weaving frequency of 0.5 to 3 Hz.

The above setting may be taught by the operator as described above, but may be set in advance.

After the input operation, when the operator gives an instruction to start the welding, the control device 2 starts the welding operation according to the procedure shown in FIG.

First, the near-point setting unit 11 of the control device 2 determines the first welding line L
And setting the first neighboring point C ₁ from inwardly folded point TP ₂ for example at a distance of 15mm on _1. However, the present invention is not limited to this, and may be set to a distance larger than the predicted maximum value of the deviation between the taught welding line and the actual welding line of the work. Usually, it is 20 mm or less. Similarly, to set a second neighboring point C ₃ on the distance between the first and for example 10mm from the inwardly folded point TP ₂ the weld line L ₁ on a line extended from the inwardly folded point TP _2.

Next, the second start point setting unit 12 of the control device 2 sets the temporary second start point C ₄ . Specifically, for example, the second welding line L
A tentative second starting point C ₄ is set as a point on the upper side of ₂ and at a distance equal to the leg length from the valley break point TP ₂ . However, the present invention is not limited to this, and can be appropriately selected from the range of, for example, 0.5 to 1.5 (the leg length).

After the calculation process (S1) of C ₁ , C ₃ , and C ₄ described above, the first welding work control unit 14 of the control device 2 causes the first welding line L
Based on the welding conditions according to the _1, point break trough from the starting point TP ₁ TP ₂
Welding operation is started toward (i.e., in the direction of the _first welding line L1) (S2).

At this time, in order to correct the deviation between the taught welding line L ₁ and the actual welding line of the work W (broken line in FIG. 4),
Arc copying control is performed. Therefore, as shown in FIG. 4, in the vicinity of the starting point TP ₁ , the welding torch 6 starts from the true welding line.
Although it is slightly off, it will soon follow the true weld line. Such arc copying control is a conventionally known technique and is disclosed in, for example, Japanese Patent Laid-Open Nos. 54-124850, 55-22488 and 58-53375.

By the arc tracing control, the welding torch 6 follows the welding line of the actual work W to proceed with the welding work, but when the welding torch 6 arrives at the neighboring corresponding point C ₁ ′ corresponding to the first neighboring point C ₁ (S
3), inwardly folded corner detection unit 13 starts the detection of changes in welding current (S4), vicinity welding operation control unit 15 moves the welding torch 6 to a point C ₂ corresponding to the inwardly folded point TP ₂ (S5).

The average value of the welding current is substantially constant when welding is performed along the normal welding line, and is 250 A, for example, as described above. However, when the welding torch 6 approaches the valley-folded corner C of the work W, for example, 10 to 20 A
A degree increase will be observed. Therefore, if an increase in the current value is detected over two weaving cycles,
It is determined that the valley C of the work is detected. The reason why such a determination is made after the detection for two cycles is to prevent an erroneous determination, and to minimize the overshoot amount.

It should be noted that such a determination can also be made by detecting a voltage change.

When the welding torch 6 reaches the second neighboring point C ₃ without being able to detect the valley fold corner C, it is determined to be overshooting (S
7) Then, the process shifts to processing for corner detection abnormality such as interruption of welding work (S8).

When the second weld near point C ₃ torch 6 detects the inwardly folded corner C before reaching the second start point setting unit 12 performs the correction operation of the second starting C ₄ and end TP ₃ (S9).

That is, since the position C ₂ ′ when the determination of the detection of the valley corner C is performed is a position which is two weaving cycles ahead of the actual valley corner C, the position C ₂ ′ is calculated from the welding speed and the weaving condition. To obtain the valley-corresponding corner corresponding point C ₂ ″. The deviation of the position of the valley-breaking point TP ₂ taught as the valley-breaking corner point C ₂ ″ is the deviation of the work W. Therefore, to obtain a _'first weld line L ₁ of the actual work W by and inwardly folded corner corresponding point C _{2 "'} the vicinity corresponding points C _1, the first weld line L ₁ which therewith taught
And the parallel movement amount and the rotational movement amount of the shift are calculated, and the second welding line L ₂ taught thereby is moved in parallel and rotationally to obtain the corrected welding line L ₂ ′. Then, the temporary second starting point C ₄ is moved onto the modified welding line L ₂ ′, and the second
The starting point C ₄ ′ is set. Further, similarly, the end point TP _{3 of the} above teaching is moved onto the correction welding line L ₂ ′, and the correction end point P ₃ ′.
To set. Further, in the present embodiment, the modified welding line L ₂ ′,
Although the rotational movement is included in the calculation of the second starting point C ₄ ′, only parallel movement may be performed. In this case, the error slightly increases, but the processing time of the arithmetic unit is reduced.

It should be noted that the welding result becomes better because the welding torch 6 goes over the actual corner C. This is because insufficient penetration at the corner C is prevented.

The cornering control unit 16 sets the welding current to 200 A, for example.
Then, the welding torch 6 is moved to the second start point C ₄ ′ while smoothly changing the angle (posture) of the welding torch 6 to the angle (posture) under the welding condition related to the second welding line L ₂ (S1).
0). However, the present invention is not limited to this, and the welding current is, for example, 1
The range of 00 to 250 A can be appropriately selected.

This welding current avoids heat concentration at the valley corner C,
Further, the welding current is set so as to avoid excessive welding beads, and the welding current is usually smaller than the welding line related to the first welding line L ₁ . In this sense, the time from the detection of the valley corner C to the second start point C ₄ ′ is preferably 5 seconds or less.

When the welding torch 6 reaches the second starting point C ₄ ′ (S1
1), the modified end point P ₃ ′ from the second start point C ₄ ′
The welding operation is performed under the welding conditions related to the second welding line L ₂ (S12). At this time, as described above, even if there is a deviation between the corrected welding line L ₂ ′ and the actual work W by the arc copying control, it is gradually corrected.

As described above, according to the welding robot apparatus 1, it is understood that it is possible to preferably perform continuous automatic welding inward even on a work including a valley corner without particularly increasing the burden of teaching. In other words, since the teaching is simple in the welding robot apparatus 1, it is possible to perform welding on a work having a valley corner without skill.

In addition, since the welding torch is moved with the welding current set to a small value in the movement to the second start point after the detection of the valley corner, heat concentration at the valley corner is prevented and excessive melting of the standing plate can be suppressed.

Further, the valley corner detection according to the present invention cannot be applied after the second pass in multi-pass welding, but
By using the information obtained by applying the second pass, it is possible to faithfully weld the actual work even after the second pass.

"Effects of the Invention" According to the present invention, the first welding line from the start point to the valley break point, the welding condition relating to the first welding line, and the second welding line from the valley break point to the end point. Condition setting means for setting welding conditions relating to the welding line and the second welding line, second starting point setting means for setting a second starting point located near the valley fold point and on the end point side of the valley fold point, First welding operation control means for advancing a welding operation in the first welding line direction under the welding conditions related to the first welding line while performing weaving and detecting the welding current or voltage, and a predetermined welding current or voltage Of the valley corner of the work by detecting the change of the corner corner detecting means, after detecting the valley corner, the cornering control means for moving the welding torch to the second start point, and after moving to the second start point, In the direction of the second welding line A welding robot apparatus is provided, which is provided with a second welding operation control means for advancing welding operation under welding conditions related to the second welding line, whereby a teaching point and a valley of an actual work are taught. Even if the corner is misaligned, the actual valley corner can be detected and the welding torch can be suitably cornered, so that the work including the valley corner can be continuously and automatically welded inward. Become.

Also, according to the present invention, as the cornering control means of the welding robot apparatus, the first corner after the detection of the valley corner is detected.
Welding current smaller than welding current and welding torch angle under the welding conditions related to the first welding line, from the welding torch angle under the welding conditions related to the first welding line to the welding torch angle under the welding conditions related to the second welding line Until it changes smoothly and continuously,
A welding robot apparatus having a cornering control means for moving the welding torch to the second starting point is provided, whereby heat concentration in the valley corner of the work is suppressed, so that the valley corner does not melt and the appearance is beautiful. Be able to perform welding.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a welding robot apparatus according to an embodiment of the present invention, FIG. 2 is a perspective view of an example of a work including a valley corner, and FIG. 3 is a main part of the operation of the apparatus shown in FIG. The flow chart, FIG. 4 is a schematic diagram of the movement locus of the welding torch by the apparatus shown in FIG. (Explanation of symbols) 1 ... Welding robot device 2 ... Control device, 4 ... Robot body 5 ... Welding machine, 6 ... Welding torch 7 ... Arc sensor, 8 ... Control panel 10 ... Condition setting section 11 ... Proximity point setting unit 12 ... Second start point setting unit 13 ... Valley break corner detection unit 14 ... First welding work control unit 15 ... Neighborhood welding work control unit 16 ... Cornering control unit 17 ... 2nd welding work control section P ₁ , TP ₁ ...... Start point, P ₂ , TP ₂ ...... valley break point P ₃ , TP ₃・ ・ ・ End point, C …… Valley break corner C ₄ ′ …… Second start point, C ₁ ... 1st neighborhood point C ₁ '... neighborhood correspondence point C ₂ ″ ... valley corner correspondence point L ₁ ...... 1st welding line, L ₂ ...... 2nd welding line W ...... work.

Claims (8)

[Claims] 1. A first welding line from a starting point to a valley break point, welding conditions relating to the first welding line, and a second welding line from the valley break point to an end point. Condition setting means for setting welding conditions relating to the second welding line, (b) second start point setting means for setting a second start point located in the vicinity of the valley break point and on the end point side of the valley break point, (c) A first welding work control means for advancing the welding work in the first welding line direction under the welding conditions relating to the first welding line while weaving and detecting the welding current or voltage, (d) Valley-breaking corner detecting means for detecting a valley-breaking corner of a work by detecting a predetermined change in welding current or voltage, (e) after detecting the valley-breaking corner, cornering control means for moving the welding torch to the second starting point, And (f) after moving to the second starting point, moving forward in the second welding line direction Second advancing welding work in welding conditions according to the second weld line
And a welding robot control device capable of continuously and automatically welding a work including a valley corner at the inner circumference. 2. The first welding line and the second welding line are set by teaching three points of a starting point, a valley bending point and an end point in the condition setting means. Welding robot equipment. 3. The welding robot apparatus according to claim 1, wherein the first welding work control means and the second welding work control means perform arc tracing control. 4. The second starting point setting means sets a tentative second starting point on the second welding line and at a distance of 0.5 or more and 1.5 or less (has a leg length) from the valley bending point, and detects it by the valley bending corner detecting means. The valley-corresponding corner corresponding point corresponding to the valley-corner corner of the work is calculated, and the position of the tentative second start point is corrected by the deviation between the valley-corner corresponding point and the taught valley-break point, and the second start point is determined. The welding robot apparatus according to any one of claims 1 to 3, which is set. 5. (a) A first welding line extending from a starting point to a valley bending point, welding conditions relating to the first welding line, and a second welding line extending from the valley bending point to an end point. Condition setting means for setting welding conditions relating to the second welding line, (b) second start point setting means for setting a second start point located in the vicinity of the valley break point and on the end point side of the valley break point, (c) A first welding operation control means that advances the welding operation in the first welding line direction under the welding conditions related to the first welding line while weaving and detecting the welding current or voltage, (d) Valley break corner detecting means for detecting a valley change corner of a workpiece by detecting a predetermined change in welding current or voltage, (e) From the welding current under the welding condition relating to the first welding line after detecting the valley break corner Welding with a small welding current and welding torch angle under the welding conditions for the first welding line Cornering control means for smoothly and continuously changing the contact torch angle to the welding torch angle under the welding condition relating to the second welding line, and moving the welding torch to the second starting point, and (f) the second starting point. After moving to the second welding line, the welding work is performed in the second welding line direction under the welding conditions related to the second welding line.
And a welding robot control device capable of continuously and automatically welding a work including a valley corner at the inner circumference. 6. The condition setting means sets a first welding line and a second welding line by teaching three points of a starting point, a valley bending point, and an ending point, as set forth in claim 5. Welding robot equipment. 7. The welding robot apparatus according to claim 5 or 6, wherein the first welding work control means and the second welding work control means perform arc tracing control. 8. The second starting point setting means sets a tentative second starting point on the second welding line and at a distance of 0.5 or more and 1.5 or less (the leg length) from the valley bending point, and the valley corner detecting means detects it. The valley-corresponding corner corresponding point corresponding to the valley-corner corner of the work is calculated, and the position of the tentative second start point is corrected by the deviation between the valley-corner corresponding point and the taught valley-break point, and the second start point is determined. The welding robot apparatus according to any one of claims 5 to 7, which is set.