JPH07232272A - Automatic welding equipment and welding method - Google Patents

Abstract

PURPOSE:To highly precisely perform sensing and to improve the working efficiency by moving the attaching position of a sensor to a moving arm part up to a proper attaching position by a moving means based on the sensor attaching position correcting value calculated with a sensor proper attaching position calculating unit. CONSTITUTION:A signal is outputted to a sensor controller 16a based on the correcting value of sensor attaching position calculated in the calculating process of the sensor proper attaching position. A biaxial oscillating motor 15 moves a sensor device 4 in x-y direction from the temporary attaching position to the movable arm's top end 13a of the movable arm part 13 up to a proper attaching position by allowing a 1st stepping motor 15a and a 2nd stepping motor 15b to drive with receiving the signal from the sensor controller 16a. In such a way, the precision of the attaching position is improved, the accurate sensing data can be obtained and welding can be accurately executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic welding apparatus for welding based on position data detected by a sensor by a welding torch attached to the tip of a movable body such as a robot arm.

[0002]

2. Description of the Related Art As a conventional automatic welding device of this type,
For example, the ones shown in FIGS. 8 and 9 are known.
In such an automatic welding apparatus 1, the sensor device 4 and the welding torch 5 are provided at the tip 3a of the movable arm 3 as the moving arm portion provided on the pedestal 2.

In this automatic welding apparatus 1, in advance of the welding preparation process, teaching (teaching) is performed on the welding torch 5 by using the workpiece 7 as the taught object having the reference welding point groups s1 to s4. Done. As this taught object,
A standard welding point group s corresponding to the planned welding site of the workpiece 7
It does not have to be the welded object 7 itself as long as it has 1 to s4.

The coordinates of the reference welding point groups s1 to s4 for welding are calculated from the position parameter of the movable arm 3 and stored in the internal central control unit.

The stored reference welding point groups s1 to s4
The sensor device 4 senses the workpiece 7 based on such coordinates. Then, the coordinates of the welding point groups s1 to s4 and the like are corrected by this sensing data, and the welding torch 5 is configured to weld the actual position-detected planned welding site (line 6 in FIG. 8). ing.

As a welding robot equipped with this type of sensor, those described in “Mechatronics System Encyclopedia”, pages 595 to 601 and the like, published by the Industrial Research Institute, Inc., are known. There is.

Regarding the sensing and the determination of the welding position, JP-A-3-32470 and JP-A-3-14 are available.
Those described in Japanese Patent No. 2069 and Japanese Patent Laid-Open No. 3-207577 are also known.

[0008]

However, in such a conventional device, it is necessary to protect the sensor device 4 from sparks generated near the tip 5a when the welding torch 5 welds an object to be welded. is there. Therefore, as shown in FIG. 9, the irradiation device 4a and the light receiving unit 4b of the sensor device 4 are oriented in a direction substantially opposite to the direction of the tip of the welding torch 5 so that the sensor device 4 is arranged at the tip 3a of the movable arm 3. I have to.

In such an automatic welding apparatus 1, since the accuracy of arranging the sensor device 4 on the tip 3a of the movable arm 3 affects the accuracy at the time of sensing, the sensor device 4 is arranged on the tip 3a of the movable arm 3. For the work to be set up, it is necessary to carry out a test several times while moving the position where the sensor device 4 is arranged to the tip 3a of the movable arm 3 and to check whether accurate welding can be performed by the sensing data. It was hard to say that the efficiency was good.

In particular, when the welding torch 5 and the sensor device 4 are removed from the tip 3a and replaced with another sensor device 4 or the like, each data stored in the internal central control unit is replaced with a new welding torch. All had to be remade to fit the positional relationship between 5 and the sensor device 4. Also in this respect, it was difficult to say that the work efficiency was good.

When a part of the optical sensor device or the like is used as the sensor device 4, the measurement region where good accuracy can be obtained is relatively narrow, and the position where the sensor device 4 is provided at the tip 3a of the movable arm 3 is set. Depending on the blind spot or the defective measurement area around the measurement area, the object to be welded may come off. For this reason, the positioning work when disposing the sensor device 4 on the tip 3a of the movable arm 3 becomes more difficult, and it is difficult to say that the work efficiency is good.

Therefore, according to the present invention, the sensor can be easily arranged, and the object to be measured can be stored in the good measurement area of the sensor to perform highly accurate sensing, and the automatic welding apparatus having good working efficiency can be provided. It is an object to provide a welding method.

[0013]

In order to solve the above-mentioned problems, according to the first aspect of the present invention, a moving arm part for driving a plurality of movable parts is welded to a welding-scheduled part of an object to be welded. A welding torch and a sensor for detecting the position of the planned welding site are provided, and a taught object having a reference welding point group corresponding to the planned welding site of the workpiece is prepared. After teaching the coordinates of the welding point group, an automatic welding device for welding the planned welding site whose position has been detected by the sensor with respect to the object to be welded, in the data obtained by teaching to the welding torch. A teaching data calculation unit that calculates the coordinates of the reference welding point group of the taught object based on the above, and calculates the coordinates of the reference welding point group of the taught object based on the sensing data by the sensor. And a sensor for calculating a sensor mounting position correction value that matches the coordinates of the reference welding point group calculated by the teaching data calculation unit with the coordinates of the reference welding point group calculated by the sensing data calculation unit. Automatic welding having a proper mounting position calculation unit and a moving unit that moves the mounting position of the sensor to the moving arm unit to the proper mounting position based on the sensor mounting position correction value calculated by the sensor proper mounting position calculation unit. It features a device.

According to another aspect of the present invention, the moving means includes a drive actuator for movably supporting the sensor with respect to the moving arm portion, and a sensor mounting position from the sensor proper mounting position calculating portion. The automatic welding apparatus according to claim 1, further comprising a control unit that receives the signal of the correction value and drives the drive actuator.

According to the third aspect,
A reference welding point group of the taught object based on the teaching process of the welding torch for teaching by applying the tip of the welding torch to the reference welding point group of the taught object and the data obtained by the teaching to the welding torch. Teaching data calculation process for calculating the coordinates of the sensor, temporary sensor mounting process for temporarily mounting the sensor on the moving arm, sensing process for sensing the sensor toward the reference welding point group of the taught object, and sensing by the sensor A sensing data calculating step of calculating the coordinates of the reference welding point group based on the data, and a reference of the reference welding point group coordinates calculated by the teaching data calculating step by the sensing data calculating step. Proper sensor mounting position calculation to calculate the sensor mounting position correction value that matches the coordinates of the welding point group of Process, moving process to move the sensor from the temporary mounting position to the moving arm part to the proper mounting position based on the sensor mounting position correction value calculated in the sensor proper mounting position calculation process, and the welded position detected by the sensor A welding method of an automatic welding apparatus having a welding step of welding a planned welding site of an object with a welding torch.

[0016]

[Operation] According to the above-mentioned structure, the moving unit can mount the sensor on the moving arm based on the sensor mounting position correction value calculated by the sensor proper mounting position calculating unit. Is moved to the proper mounting position,
The work of disposing the sensor on the moving arm portion can be easily performed, the work efficiency is good, and the accuracy of the mounting position is improved, so that accurate sensing data can be obtained.

In particular, when replacing the welding torch or sensor, it is not necessary to recreate each data stored in the internal central control unit so as to match the new positional relationship between the welding torch and the sensor. Can be used. For this reason,
Furthermore, the working efficiency is good.

Further, as the sensor, even when using a part of the optical sensor device or the like which has a relatively narrow measurement area where good accuracy can be obtained, the object to be welded can be easily brought into the good measurement area in the approximate center of the measurement area. You can pay. Therefore, the positioning work when the sensor is provided on the moving arm portion can be easily performed, and the work efficiency is good.

According to another aspect of the present invention, the control means of the moving means receives the signal of the sensor mounting position correction value from the sensor proper mounting position calculating portion and drives the drive actuator. For this reason, the work of automatically moving the sensor to the proper mounting position of the moving arm portion is performed, and the work efficiency is further improved.

And, in the one described in claim 3,
In the teaching process of the welding torch, the tip of the welding torch is applied to the reference welding point group of the taught object to perform teaching.

In the teaching data calculation step, the coordinates of the reference welding point group of the taught object are calculated based on the data obtained by teaching the welding torch.

In the sensor temporary attaching step, the sensor is temporarily attached to the moving arm portion.

In the sensing process, the sensor is directed to the reference welding point group of the object to be sensed.

In the sensing data calculation step, the coordinates of the reference welding point group of the object to be taught are calculated based on the sensing data from the sensor.

In the sensor proper mounting position calculating step, the sensor mounting position correction in which the coordinates of the reference welding point group calculated in the teaching data calculating step are made to match the coordinates of the reference welding point group calculated in the sensing data calculating step The value is calculated.

In the moving step, the sensor is moved from the temporary mounting position to the moving arm portion to the proper mounting position based on the sensor mounting position correction value calculated in the sensor proper mounting position calculating step.

Then, in the welding process, the to-be-welded portion of the object to be welded whose position is detected by the sensor is welded by the welding torch.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings.

1 to 6 show an embodiment of the present invention. The same or equivalent parts as those of the conventional example are designated by the same reference numerals.

First, the structure will be described.
A welding robot as an automatic welding apparatus of this embodiment is shown, and this welding robot 11 is provided with a rotating base 12 which is rotationally driven in a horizontal direction on a pedestal 2.

The rotary base 12 is provided with a moving arm portion 13 which is three-dimensionally driven. The moving arm portion 13 mainly includes a plurality of movable arms 13a, 1 that can be driven in a predetermined direction.
3b and 13c and a plurality of movable portions 14a, 14b and 14c which are rotatably connected between the movable arms 13a ... And which are driven in a predetermined direction.

Each of the movable parts 14a has a drive motor driven by a central controller 16 in the welding robot 11, and the movable arm 13a is driven in a predetermined manner based on a signal from the central controller 16. I am trying to move in the direction. Further, the position parameter of the moving arm portion 13 is calculated from the drive amount of these drive motors. Regarding the detection of the position parameter of the moving arm portion 13, an absolute encoder or a potentiometer may be separately provided in each movable portion 14a to detect the position parameter.

Of these, a welding torch 5 is fixed to the tip of the movable arm 13c for welding the planned welding portion of the structure 7 as the object to be welded. In addition, this movable arm 13
An optical sensor device 4 as a sensor is connected to c via a biaxial swinging motor 15 as a part of a moving means for moving the mounting position to the moving arm portion 13 to an appropriate mounting position. There is.

The biaxial swing motor 15 includes a first stepping motor 15a as a drive actuator for supporting the sensor device 4 so as to be movable in the X direction with respect to the tip 13a of the moving arm portion 13, and the sensor device 4 Is constituted by a second stepping motor 15b as a drive actuator that supports the movable arm 13 so as to be movable in the Y direction with respect to the distal end 13a thereof.

These first stepping motors 15a
And the second stepping motor 15b are connected to a sensor controller 16a which is a control means as a part of the moving means. And this sensor controller 16
When the signal of the sensor mounting position correction value from a is received, this first
The stepping motor 15a and the second stepping motor 15b are driven to move the irradiation unit 4a and the light receiving unit 4b of the sensor device 4 so as to face in a predetermined direction.

The laser light 10 emitted from this irradiation portion is reflected in the vicinity of the planned welding portion of the structure 7 as the object to be measured, and the reflected laser light is received by the light receiving portion 4b.
And the position on the structure 7 to be welded is detected.

The sensor device 4 is connected to the sensor controller 16a. Then, the shape data of the structure 7 detected by the sensor device 4 is transmitted to the sensor controller 16a.

The sensor controller 16a receives the shape data and calculates the coordinate values of the gap G, the step D, the edge E, etc. between the column 7a and the joint pipe 7b which form the structure 7. Means, an optimum condition selecting means for selecting an optimum welding condition from the shape data from the optimum welding condition database stored in advance by the welding robot 11, and a welding planned site coordinate and an optimum welding condition signal to the welding robot 11. And a signal transmitting means for transmitting. And this sensor controller 16a
Is connected to the central control unit 16 of the welding robot 11.

Central control unit 16 of the welding robot 11
In the optimum welding condition database 17 therein, information such as current, voltage, speed, torch angle and aiming angle for determining welding conditions is stored based on the knowledge and experience of a skilled worker.

The central control unit 16 also includes a teaching data calculation unit 18 for calculating the coordinates of the reference welding point group of the object to be taught based on the data obtained by teaching the welding torch 5, and the sensor. A sensing data calculation unit 19 that calculates the coordinates of the reference welding point group of the object to be taught based on the sensing data of the device 4, and the coordinates of the reference welding point group calculated by the teaching data calculation unit 18 are calculated as sensing data. A sensor proper mounting position calculation unit 20 that calculates a sensor mounting position correction value that matches the coordinates of the reference welding point group calculated by the unit 19, and a sensor mounting position correction value that is calculated by this sensor proper mounting position calculation unit 20. Based on the above, the sensor device 4 moves the position to be attached to the tip 13a of the moving arm portion 13 to the proper attachment position. And a sensor controller 16a of the moving means for moving by driving the biaxial oscillating motor 15.

Next, the operation of the first embodiment will be described with reference to FIGS.
Description will be given along the flowcharts of FIGS. 6 and 7.

In the first embodiment, in the welding preparatory step performed in advance, the structure 7 which is the object to be welded as the object to be taught having the reference welding point groups s1 to s4 and the like is used for the welding torch 5. Teaching is performed. The object to be taught need not be the structure 7 itself as long as it has the reference welding point groups s1 to s4 corresponding to the planned welding site of the object to be welded 7.

First, as shown in FIG. 3, in the teaching process of the welding torch 5 in step 1, the tip 5a of the welding torch 5 is processed.
Is applied to the reference welding point groups s1 to s4, etc., and teaching is performed. In this teaching, the two points at both ends in the case of a straight line and the three points in the case of a circular arc are taught by the computing ability of the central control unit 16.
The tip 5a can be accurately moved by performing linear interpolation or circular interpolation calculation, and also by using a wrist correction function that corrects the planned welding site by the welding torch 5 so that it does not change even if the wrist posture changes. I can.

In the teaching data calculating step of step 2, based on the parameter data obtained by the teaching data calculating section 18 by teaching the welding torch 5, the reference welding point group s1 of the taught object as shown in FIG. The coordinates such as s4 are calculated.

Next, in the temporary sensor mounting step of step 3, the sensor device 4 preliminarily sets the movable arm tip 1 of the moving arm portion 13.
3a is temporarily attached via the biaxial swing motor 15. This temporary mounting does not require the precision of the mounting position to be as high as in the conventional case. Therefore, the work of disposing the sensor device 4 at the movable arm tip 13a of the moving arm portion 13 is
It can be done easily and has good work efficiency.

In the sensing step of step 4, as shown in FIG. 4, the irradiation portion 4a of the sensor device 4 is directed toward the reference welding point groups s1 to s4 of the object to be sensed and sensing is performed.

In the sensing data calculating step of step 5, the sensing data calculating section 19 as shown in FIG.
Then, the coordinates of the reference welding point groups s1 to s4, etc. of the object to be taught are calculated based on the sensing data by the sensor device 4. In the measurement by the optical sensor device 4, the planned welding site is not directly detected, but the spatial features such as the end portion and the gap are once extracted, and the welding point or the welding line which is a collection of the welding points is extracted. As the coordinates of the welding point group, the coordinates of the planned welding site are grasped.

Further, in the measurement by the optical sensor device 4, when the planned welding site has a curved surface and diffuse reflection occurs, the relative positional relationship with the planned welding site other than the planned welding site of the workpiece. It is also possible to measure the outer shape of a portion where the constant welding temperature is constant and take into account the relative positional relationship to calculate the coordinates of the welding point group of the planned welding portion.

Then, in the step 6 of calculating the sensor proper mounting position, the sensor proper mounting position calculating section 20
The coordinates of the reference welding point group s1 to s4 calculated in the teaching data calculation step are the coordinates s1 to the reference welding point group calculated in the sensing data calculation step.
A sensor mounting position correction value H that matches s4 and the like is calculated.

In the moving step of step 7, as shown in FIG. 6, a signal is output to the sensor controller 16a based on the sensor mounting position correction value H calculated in the sensor proper mounting position calculating step. In the biaxial rocking motor 15, the first stepping motor 15a and the second stepping motor 15b send signals from the sensor controller 16a from a temporary mounting position to the movable arm tip 13a of the moving arm portion 13 to a proper mounting position. By receiving and driving, the sensor device 4 is moved in the xy direction.

Then, in the welding process of step 8, the structure 7 is welded by the welding torch 5 as shown in FIG. 1 along the line 6 which is the planned welding site of the workpiece detected by the sensor device 4. To be done. At this time, since the mounting position of the sensor device 4 has been moved from the temporary mounting position to the proper mounting position, the accuracy of the mounting position is improved and accurate sensing data can be obtained. Therefore, the welding torch 5 tip 5a can be welded while accurately tracing the line 6.

For this reason, as the sensor, a part of the optical sensor device 4 in which the measurement region where good accuracy can be obtained is relatively narrow.
Even if such a structure is used, the structure 7 can be easily accommodated in the good measurement region substantially in the center of the measurement region. Therefore, the positioning operation when disposing the sensor device 4 on the moving arm portion 13 can be easily performed.

In particular, when the welding torch 5 and the sensor device 4 are replaced, each data stored in the internal central control device 16 is adapted to the new positional relationship between the welding torch 5 and the sensor device 4. You can use it as it is without having to remake everything. Therefore, work efficiency is further improved.

Moreover, in this first embodiment, the moving means 2
The sensor controller 16a of No. 1 receives the signal of the sensor mounting position correction value H from the sensor proper mounting position calculation unit 20, and drives the stepping motors 15a and 15b of the biaxial rocking motor 15 which is a drive actuator. For this reason, since the work of automatically moving the sensor device 4 to the proper mounting position of the moving arm portion 13 is performed, the work efficiency is further improved.

After welding, when another structure 7 having the same shape is to be welded, the process returns to the welding process of step 8 and the sensor device 4 is used.
As shown in FIG. 1, the welding of the structure 7 by the welding torch 5 is repeated along the line 6 which is the planned welding site of the workpiece whose position is detected by. At this time, since the mounting position of the sensor device 4 has been moved from the temporary mounting position to the proper mounting position, the accuracy of the mounting position is also improved, and even if the sensing by the sensor device 4 is performed by another structure 7, it is accurate. Sensing data can be obtained. Therefore, the welding torch 5
The tip 5a can be welded while tracing the line 6 accurately.

After welding, when welding an object to be welded such as a structure having another shape, the process returns to step 1 and steps 2 to 8 are performed again from the teaching process of the welding torch.

At this time, since the mounting position of the sensor device 4 has already been moved to the accurate good measurement position, step 3
Up to 7 can be omitted. For this reason, the welding process of step 8 can be started immediately after the teaching of step 1, and the work efficiency is further improved.

Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific structure is not limited to this embodiment, and the present invention can be applied even if there is a design change or the like within the scope not departing from the gist of the present invention. include. For example, in the first embodiment, the sensor controller 16a of the moving means 21 receives the signal of the sensor mounting position correction value H from the sensor proper mounting position calculating section 20, and the biaxial rocking motor 15 which is the drive actuator. Although each of the stepping motors 15a and 15b is driven, the present invention is not limited to this. For example, instead of the two-axis rocking motor 15, another multi-axis rocking motor, a hydraulic servo motor, or the like may be used as the sensor device 4. An actuator or the like for movably supporting the sensor is used, or the sensor controller 16a of the moving means 21 uses the sensor proper mounting position calculation unit 20
When the sensor mounting position correction value H signal from
The correction required value may be output to a monitor or the like to be connected, and the operator may manually move the sensor device 4 to the proper mounting position of the moving arm portion 13.

In the first embodiment, after the teaching process of the welding torch 5 of step 1, the sensing process of the sensor device 4 of step 5 is performed, but the present invention is not limited to this. 2 and steps 3 to 5 may be replaced with each other, and after the sensing process by the sensor device 4 is performed, the teaching process of the welding torch 5 may be performed.

[0060]

As described above, according to the first aspect of the present invention having such a structure, the moving means moves the sensor based on the sensor mounting position correction value calculated by the sensor proper mounting position calculating section. Since the mounting position on the moving arm part is moved to the proper mounting position, the work of disposing the sensor on the moving arm part can be easily performed, and the working efficiency is good, and
The accuracy of the mounting position is also improved and accurate sensing data can be obtained.

In particular, when the welding torch and the sensor are replaced, it is not necessary to recreate all the data stored in the internal central control unit so as to match the new positional relationship between the welding torch and the sensor, and the data is stored as it is. Can be used. For this reason,
Furthermore, the working efficiency is good.

Further, even when using a part of the optical sensor device or the like having a relatively narrow measurement area where good accuracy can be obtained as the sensor, the object to be welded can be easily brought into the good measurement area substantially in the center of the measurement area. You can pay. Therefore, the positioning work when the sensor is provided on the moving arm portion can be easily performed, and the work efficiency is good.

Further, according to the second aspect of the invention, the control means of the moving means receives the signal of the sensor mounting position correction value from the sensor proper mounting position calculating portion and drives the drive actuator. For this reason, the work of automatically moving the sensor to the proper mounting position of the moving arm portion is performed, and the work efficiency is further improved.

Then, according to the third aspect,
In the teaching process of the welding torch, the tip of the welding torch is applied to the reference welding point group of the taught object to perform teaching.

In the teaching data calculating step, the coordinates of the reference welding point group of the object to be taught are calculated based on the data obtained by teaching the welding torch.

In the sensor temporary attaching step, the sensor is temporarily attached to the moving arm portion.

In the sensing step, the sensor is aimed at the reference welding point group of the object to be sensed for sensing.

In the sensing data calculation step, the coordinates of the reference welding point group of the object to be taught are calculated based on the sensing data from the sensor.

In the sensor proper mounting position calculation step, the sensor mounting position correction in which the coordinates of the reference welding point group calculated in the teaching data calculation step are made to match the coordinates of the reference welding point group calculated in the sensing data calculation step The value is calculated.

In the moving step, the sensor is moved from the temporary mounting position to the moving arm portion to the proper mounting position based on the sensor mounting position correction value calculated in the sensor proper mounting position calculating step.

Then, in the welding process, the to-be-welded portion of the workpiece whose position has been detected by the sensor is welded by the welding torch.

Therefore, it is possible to provide an automatic welding apparatus and welding method in which the sensor can be easily arranged, the object to be measured can be stored in the good measurement area of the sensor for highly accurate sensing, and the work efficiency is good. It has a practically useful effect that it can be provided.

[Brief description of drawings]

FIG. 1 is a perspective view showing a welding process of an automatic welding device according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating an automatic welding apparatus of the same embodiment and explaining the configuration.

FIG. 3 is a perspective view showing an automatic welding apparatus of the same embodiment and explaining a teaching process.

FIG. 4 is a perspective view showing the automatic welding apparatus of the same embodiment and showing how the sensor apparatus is performing sensing.

FIG. 5 is a perspective view schematically showing the automatic welding apparatus of the same embodiment and showing coordinate positions sensed by a sensor device and coordinate positions obtained by teaching.

FIG. 6 is a perspective view showing the automatic welding apparatus of the same embodiment and schematically showing how the sensor device is moved.

FIG. 7 is a flow chart showing work steps of the same embodiment.

FIG. 8 is a perspective view of the entire system showing a conventional welding robot.

FIG. 9 is a perspective view of a tip portion of a movable arm, showing a welding robot of a conventional example.

[Explanation of symbols]

 4 Sensor device (sensor) 5 Welding torch 7 Structure (object to be welded) 11 Welding robot (automatic welding device) 13 Moving arm 14a, 14b, 14c Moving part Moving means 21 15 Biaxial swing motor 16a Sensor controller (control) 18) Teaching data calculation unit 19 Sensing data calculation unit 20 Sensor mounting position calculation unit s1 to s4 Reference welding point group

Claims (3)

[Claims] 1. A moving arm part for driving a plurality of movable parts is provided with a welding torch for welding a planned welding site of an object to be welded and a sensor for detecting the position of the planned welding site. A taught object having a reference welding point group corresponding to a planned welding site is prepared, and after teaching the coordinates of the reference welding point group on the taught object, the position of the teaching object is measured by the sensor. An automatic welding device for welding a detected planned welding site, a teaching data calculation unit that calculates the coordinates of a reference welding point group of the taught object based on data obtained by teaching to the welding torch, A sensing data calculation unit that calculates the coordinates of the reference welding point group based on the sensing data from the sensor, and a reference calculated by the teaching data calculation unit. Calculated by the sensor proper mounting position calculation unit that calculates a sensor mounting position correction value that matches the coordinates of the welding point group with the coordinates of the reference welding point group calculated by the sensing data calculation unit, and the sensor proper mounting position calculation unit. And a moving means for moving the mounting position of the sensor to the moving arm portion to a proper mounting position based on the sensor mounting position correction value. 2. The driving means receives a signal of a sensor mounting position correction value from the sensor proper mounting position calculating portion, the driving actuator supporting the sensor movably with respect to the moving arm portion, and the driving actuator. The automatic welding apparatus according to claim 1, further comprising: a control unit that drives the. 3. A teaching process of a welding torch in which teaching is performed by applying the tip of the welding torch to a reference welding point group of the taught object, and the teaching object is taught based on data obtained by teaching the welding torch. Teaching data calculation process that calculates the coordinates of the standard welding point group, sensor temporary mounting process that temporarily mounts the sensor on the moving arm, and sensing process that performs the sensor toward the reference welding point group of the taught object. A sensing data calculation step of calculating the coordinates of the reference welding point group of the taught object based on the sensing data of the sensor; and a sensing data calculation step of calculating the coordinates of the reference welding point group calculated in the teaching data calculation step. A sensor attachment position correction value that matches the coordinates of the reference welding point group calculated by Proper mounting position calculation process, moving process to move the sensor from the temporary mounting position to the moving arm to the proper mounting position based on the sensor mounting position correction value calculated in the sensor proper mounting position calculation process, and position detection by the sensor And a welding step of welding a planned welding site of the welded object with a welding torch.