JP2009006383A - Welding condition correcting method of automatic welding apparatus, and automatic welding apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a welding condition correcting method of an automatic welding apparatus capable of preventing any burn-through in the adaptive welding, and the automatic welding apparatus. <P>SOLUTION: A control device 10 of a welding robot comprises an image pickup camera 25 which is supported by a manipulator M to acquire the shape of a bead formed by the welding by a welding torch 14, and a camera control device CCU for calculating the reinforcement height of the bead based on the image pickup data of the image pickup camera 25. The control device 10 comprises a robot control device RC which performs the correction so that the welding current is converged to the determined value according to information on the groove of a weld joint as the reinforcement height of the bead is increased, and the heat input of the welding current determined by the gap of the weld joint is decreased as the reinforcement height of the bead is decreased. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a welding condition correction method for an automatic welding apparatus and an automatic welding apparatus.

  In the arc welding robot system that realizes the laser sensor copying technique, a welding torch 50 and a laser sensor LS are provided at the free end of a manipulator M as shown in FIG. The laser sensor control device LU performs image analysis based on distance measurement data acquired by the laser sensor LS preceding the welding torch 50. Then, the laser sensor control device LU acquires groove information including groove feature points and physical quantities (gap amount, groove angle, groove area, etc. according to the groove) by image analysis, and the obtained characteristics. A three-dimensional trajectory of the welding torch 50 is generated by connecting the points.

  Here, in the obtained three-dimensional trajectory, the tangent vector is defined as a traveling direction vector. The laser sensor control device LU defines a feature line in the groove as a reference angle and gives a target relative angle with respect to the reference angle with respect to the groove information (that is, the feature point and the physical quantity). Together with the vector, the target posture of the welding torch 50 with respect to the groove is generated.

  For example, FIG. 8 shows groove information when image analysis is performed on the lap joint based on distance measurement data sampled by the laser sensor LS. In the case of a lap joint, as shown in FIG. 8, a point that is an end angle of an upper plate (not shown) is a feature point. In this case, it is possible to generate the target posture of the welding torch 50 with respect to the groove together with the traveling direction vector by setting the groove normal line through which the feature point passes as a reference angle and giving a target relative angle with respect to the reference angle. it can.

FIG. 9 shows an example in which the three-dimensional trajectory of the welding torch 50 is generated by connecting the characteristic points obtained for the lap joint.
By the way, only the position / posture of the feature point with respect to the groove coordinate system can be calculated only by the groove information based on the distance measurement data obtained from the laser sensor LS. Therefore, the robot controller RC transmits the current coordinates of the welding torch 50 in the robot coordinate system to the laser sensor controller LU.

  The laser sensor control device LU receives the current position in the robot coordinate system of the welding torch 50 received, the feature point coordinates acquired by image analysis, and the speed (velocity data) given in advance, so that the target position (in the robot coordinate system) That is, the target coordinates are calculated and returned to the robot controller RC.

In the robot controller RC, the interpolation point generated from the teaching data is replaced with the received target position (target coordinate), and copying is performed by operating the manipulator M.
Further, the laser sensor control device LU calculates groove information such as a gap amount and a groove area in real time in the process of obtaining the target position (target coordinates). Therefore, the laser sensor control device LU returns the groove information to the robot control device RC together with the return of the target position (target coordinates). For example, the laser sensor control device LU calculates the gap amount G for the fillet joint shown in FIG. 10A and the gap amount G and the groove area for the butt joint shown in FIG. 10B.

  By the way, in the adaptive welding function using the laser sensor LS, the robot controller RC refers to a preset adaptive welding condition table, and refers to a welding condition (for example, welding current or the like) commanded to the welding power source WPS according to the groove information. The welding voltage can be changed in real time. For example, Table 1 shows an example of an adaptive welding condition table that changes a welding current, which is one of the welding conditions, according to the gap amount G as groove information. In this example, the welding current Is changes stepwise according to the gap amount G. Table 2 shows another example of an adaptive welding condition table in which the welding current is changed in accordance with the gap amount G. In this example, when the gap amount G is 0.0 mm to 3.0 mm, the welding current Is changes linearly.

  In both Tables 1 and 2, the current is set to be constant at the upper limit value when the gap amount G is 3.0 mm or more. By setting an appropriate adaptive welding condition table by such a method and changing the welding conditions in real time according to the gap amount, a desired welding operation can be performed while filling the gap.

  Adaptive welding is effective in medium thickness plate (that is, plate thickness of approximately 4 mm or more) welding. However, when the plate thickness is reduced, if the welding current (that is, the command current) is increased in proportion to the gap amount or the groove area in order to fill the gap, the heat input becomes too much and the burnout is lost. It may occur.

  The objective of this invention is providing the welding condition correction method and automatic welding apparatus of an automatic welding apparatus which can prevent a burn-off in adaptive welding.

  In order to solve the above-mentioned problems, the invention described in claim 1 is directed to a welding condition correction method for an automatic welding apparatus that determines welding conditions according to groove information of a welded joint. The higher the value, the more the welding condition determined according to the groove information determined according to the groove information of the welded joint is corrected, and the lower the height of the bead, the lower the welding condition determined according to the groove information of the welded joint. The gist of the present invention is a welding condition correction method for an automatic welding apparatus, wherein the correction is made so that the heat input becomes smaller.

According to a second aspect of the present invention, in the first aspect, the groove information is a gap amount or a groove area.
According to a third aspect of the present invention, in the first or second aspect, when the surplus height is within a predetermined range, as the surplus height approaches the upper limit of the predetermined range, the groove of the weld joint is Correction is made so that it converges to the welding conditions determined in accordance with the information, and as the surplus height approaches the lower limit of the predetermined range, the welding condition is determined to be greater than the welding conditions determined in accordance with the groove information of the weld joint. The correction is made so that the heat is reduced.

  According to a fourth aspect of the present invention, there is provided groove information acquisition means for acquiring groove information based on measurement data of a measurement means for measuring a cross-sectional shape of a welded joint, and calculation means for calculating welding conditions based on the groove information. In an automatic welding apparatus that performs welding with a welding torch provided in a manipulator according to the welding conditions, a shape that is supported by the manipulator and that is formed by welding with the welding torch is obtained. According to the acquisition means, the surplus height calculation means for calculating the surplus height of the bead based on the acquisition data of the shape acquisition means, and according to the groove information of the weld joint as the surplus height of the bead increases. The welding conditions determined in accordance with the groove information of the welded joint are reduced as the bead surplus height is lowered. Further comprising a correction means for correcting such that it is an gist automatic welding device according to claim.

According to a fifth aspect of the present invention, in the fourth aspect, the groove information is a gap amount or a groove area.
According to a sixth aspect of the present invention, in the fourth or fifth aspect, when the surplus height is within a predetermined range, the correction means is configured so that the surplus height approaches the upper limit of the predetermined range. Correction is made so as to converge to the welding conditions determined according to the groove information of the welded joint, and the welding determined according to the groove information of the welded joint as the surplus height approaches the lower limit of the predetermined range. The condition is corrected so that the heat input becomes smaller.

  According to the method of the first aspect of the invention, as the surplus height of the bead increases, correction is made so as to converge to the welding conditions determined according to the groove information of the welded joint, and the surplus height of the bead decreases. The welding conditions determined in accordance with the groove information of the welded joint are corrected so that the heat input becomes smaller. Therefore, in adaptive welding, it is possible to prevent the melt-out.

  According to the method of the invention of claim 2, by setting the groove information as the gap amount or the groove area, the welding current is determined by the gap amount or the groove area, and by correcting the welding current, The effect of claim 1 can be achieved.

  According to the method of the invention of claim 3, when the surplus height is within a predetermined range, the surplus height is determined according to the groove information of the welded joint as it approaches the upper limit of the predetermined range. Correction is made so as to converge to the welding conditions, and as the surplus height approaches the lower limit of the predetermined range, the welding conditions determined according to the groove information of the welded joint are corrected so that the heat input becomes smaller. . As a result, according to the third aspect of the present invention, when the surplus height is within the predetermined range, it is possible to prevent burn-out in adaptive welding.

  According to the automatic welding device of claim 4, the higher the height of the bead, the correction is made so as to converge to the welding conditions determined according to the groove information of the welded joint, and the height of the bead is lower. The welding conditions determined in accordance with the groove information of the welded joint are corrected so that the heat input becomes smaller. Therefore, in the adaptive welding, it is possible to prevent the burnout from occurring.

  According to the automatic welding apparatus of claim 5, by setting the groove information as the gap amount or the groove area, the welding current is determined by the gap amount or the groove area, and by correcting the welding current, The effect of claim 4 can be achieved.

  According to the automatic welding apparatus of claim 6, when the surplus height is within a predetermined range, the surplus height is determined according to the groove information of the welded joint as it approaches the upper limit of the predetermined range. Correction is made so as to converge to the welding conditions, and as the surplus height approaches the lower limit of the predetermined range, the welding conditions determined according to the groove information of the welded joint are corrected so that the heat input becomes smaller. . As a result, in the automatic welding apparatus according to the sixth aspect, when the surplus height is within a predetermined range, it is possible to prevent the melt-off in the adaptive welding.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment in which a welding condition correction method and automatic welding apparatus for an automatic welding apparatus according to the present invention are embodied as a welding condition correction method for an arc welding robot and a control apparatus for an arc welding robot will be described with reference to FIGS. To do. FIG. 1 is a block diagram showing a configuration of an arc welding robot control device 10 (hereinafter referred to as a welding robot control device 10).

The control device 10 of the welding robot controls the workpiece (work object) W so as to automatically perform arc welding.
The welding robot control device 10 includes a manipulator M that performs a welding operation, a robot control device RC that controls the manipulator M, a laser sensor LS as a measurement unit that detects the shape of the workpiece W, and a laser that controls the laser sensor LS. A sensor control unit LU and the like are provided.

  In addition, a teach pendant TP as a portable operation unit is connected to the robot controller RC. The teach pendant TP is provided with a keyboard and a liquid crystal display (not shown). Various teaching data are input to the robot controller RC by the keyboard.

  The manipulator M includes a base member 12 fixed to a floor or the like, and a plurality of arms 13 connected via a plurality of shafts. A welding torch 14 as a work tool is provided at the distal end portion of the arm 13 located on the most distal side. The welding torch 14 includes a wire 15 as a filler material, generates an arc between the tip of the wire 15 fed by a feeding device (not shown) and the workpiece W, and welds the wire 15 with the heat. To weld the workpiece W. A plurality of motors (not shown) are disposed between the arms 13, and the welding torch 14 can be freely moved back and forth and left and right by driving the motors. Note that front and rear refers to the direction in which the welding torch 14 travels along the weld line (that is, the welding progress direction indicated by the arrow in FIG. 1) as the front, and the direction opposite to 180 degrees as the rear. Left and right are referred to as left and right with reference to the direction in which the person travels. Weaving is possible by moving the welding torch 14 in the forward and leftward directions.

  The robot controller RC is composed of a computer as shown in FIG. The robot controller RC is a CPU (Central Processing Unit) 20, various programs for controlling the manipulator M, a rewritable EEPROM 21 that stores a plurality of image analysis programs prepared according to various groove shapes, A RAM 22 serving as a work memory and a storage unit 23 as a storage unit including a rewritable nonvolatile memory for storing various data are provided. In the present embodiment, the robot control device RC corresponds to a calculation unit and a correction unit.

  The storage unit 23 includes a first storage area 23a and a second storage area 23b. The storage unit 23 also includes a teaching data storage area (not shown) for storing teaching data such as a route input by the keyboard. The first storage area 23a stores the adaptive welding condition table of Table 2 described above. Note that the adaptive welding condition table of Table 1 described above may be stored in the first storage area 23a. In this embodiment, for convenience of explanation, as an example of welding a butt joint, if the gap amount G is increased as shown in Tables 1 and 2, the welding current Is as a welding condition is set to increase. The adaptive welding condition table is used. In the adaptive welding condition table of Table 1, when the gap amount G increases, the welding current Is as a welding condition increases stepwise, and in the adaptive welding condition table of Table 2, the welding current Is increases when the gap amount G increases. Increases linearly.

  The second storage area 23b stores a bead appearance adjustment table (see Table 3) described later. The bead appearance adjustment table includes a bead surplus height Cv and a relative current IR. The relative current IR corresponds to a correction value for the welding current.

ビードの余盛り高さＣｖは図４に示すように、ワークＷに対して形成されるビードＢにおいて、ワークＷの任意の基準部位（図４の突き合わせ継ぎ手の例では、ワークＷの上面）からビードＢの頂点までの距離（すなわち、高さ）である。なお、ビードＢが基準部位よりも低くなって凹状となった場合には、ビードＢの余盛り高さＣｖは深さを含む。基準部位からのビードＢの頂点までの高さは＋値で示され、基準部位からビードＢの深さは−値で示される。撮像カメラ２５は、形状取得手段に相当する。

As shown in FIG. 4, the extra height Cv of the bead is determined from an arbitrary reference portion of the workpiece W (the upper surface of the workpiece W in the example of the butt joint in FIG. 4) in the bead B formed with respect to the workpiece W. This is the distance (ie, height) to the apex of bead B. In addition, when the bead B becomes lower than the reference portion and becomes concave, the surplus height Cv of the bead B includes the depth. The height from the reference part to the apex of the bead B is indicated by a positive value, and the depth of the bead B from the reference part is indicated by a negative value. The imaging camera 25 corresponds to a shape acquisition unit.

  In the bead appearance adjustment table shown in Table 3, the relative current IR is set to 0 A when the surplus height Cv is larger than 2.0 mm, and the relative current IR is surpassed when the surplus height Cv is larger than 1.0 mm and up to 2.0 mm. -10A. The bead appearance adjustment table has a relative current IR of −20 A when the surplus height Cv is greater than 0.0 mm and up to 1.0 mm, and a relative current IR of −30 A when the surplus height Cv is 0.0 mm. It is said. As described above, the relative current IR is set as the correction value of the welding current so that the surplus height Cv changes stepwise according to the surplus height Cv in the range of the lower limit value 0.0 mm to the upper limit value 2.0 mm. Has been. That is, the absolute value of the relative current IR that is the correction value is set to be smaller as the surplus height Cv is higher. Further, the absolute value of the relative current IR is set to increase as the surplus height Cv decreases.

  When the welding current Is as the welding condition is calculated from the adaptive welding condition table according to the gap amount G, the welding current is corrected by calculating (Is + IR). Note that the numerical values shown in the bead appearance adjustment table in Table 3 are examples and are not limited to these values, but the point is that the melting occurs under various conditions when welding. The values obtained by testing or the like may be tabulated so that no drop occurs.

For example, it goes without saying that the lower limit value of the surplus height Cv may be appropriately changed so as to include a negative value.
The robot controller RC controls the motor to drive the welding torch 14 along a route that is preset teaching data. Further, the robot controller RC outputs welding conditions such as a welding current and a welding voltage to the welding power source WPS, and causes the welding operation to be performed by electric power supplied from the welding power source WPS through the power cable PK.

  The laser sensor LS is a scanning type laser sensor that measures the distance to the workpiece W by light emission and light reception of a laser, is mounted on the welding torch 14, and the direction in which the welding torch 14 travels along the welding line (that is, FIG. The distance of the groove opening (that is, the unwelded portion) portion on the side of the traveling direction indicated by the arrow 1 is measured. The laser sensor LS includes a light emitting unit that emits light toward the workpiece W, a light receiving unit that receives the laser reflected by the workpiece W, and the like (both not shown). The laser emitted from the light emitting unit is irregularly reflected by the workpiece W and received by the light receiving unit. The light receiving unit is constituted by a CCD line sensor, for example, and measures the distance from the center of gravity of the received light amount distribution to the workpiece W.

  The laser sensor control device LU drives and controls the laser sensor LS, and in the process of obtaining the target position (target coordinates) of the welding torch 14 in the same manner as in the prior art, the gap amount and the opening amount are measured from the measured distance measurement data (distance information). The groove information such as the tip area and cross-sectional shape is calculated in real time. The laser sensor control device LU returns the groove information including the cross-sectional shape of the weld joint together with the return of the target position (target coordinates) to the robot control device RC.

  The laser sensor control device LU includes a central processing unit (CPU), a computer having a plurality of image analysis programs prepared according to various groove shapes, a memory for storing various data, and the like. The laser sensor control device LU corresponds to groove information acquisition means.

  The welding torch 14 is equipped with an imaging camera 25 that images a bead formed on the side opposite to the traveling direction of the welding torch 14. In the present embodiment, the imaging camera 25 is composed of a CCD camera. However, the imaging camera 25 may be a camera composed of another imaging element (for example, CMOS), and is not limited. The imaging camera 25 corresponds to a shape acquisition unit.

  The camera control unit CCU includes a central processing unit (CPU), a computer having an image analysis program prepared according to various groove shapes, a memory for storing various data, and the like. The camera control unit CCU performs image processing of imaging data as acquired data acquired by the imaging camera 25, calculates (that is, analyzes) the surplus height Cv of the captured bead B, and controls the surplus height Cv by robot control. Notify device RC. The camera control unit CCU corresponds to extra height calculation means.

Next, adaptive welding control in the robot controller 10 will be described. The workpiece W to be welded is a butt joint as a weld joint.
As a precondition, the welding progress direction of the welding torch 14 is set to be the X axis or Y axis of the tool coordinate system, and the laser sensor LS is attached so as to be parallel to the X axis or Y axis. The The laser sensor LS (that is, the sensor head LSa shown in FIG. 2B) is configured to irradiate a laser beam at a position spaced a predetermined distance from the tip of the welding torch 14 toward the welding direction. The distance between the laser toe point on the tool coordinate system that is a predetermined distance away from the tip of the welding torch 14 and the welding direction is referred to as the sensor look-ahead distance T. In this embodiment, the + X direction is set as the welding progress direction. The laser sensor LS may be attached obliquely with respect to the welding torch 14 as indicated by a two-dot chain line in FIG.

  In addition, teaching data indicating the operation of the manipulator M when welding is performed, welding conditions, and the like are input to the robot controller RC via the teach pendant TP before the welding operation is performed. It is stored in the storage area 23b.

  For convenience of explanation, after the welding torch 14 is moved to the detected welding start point by the laser sensor LS preceding the welding torch 14, copying and welding are performed along a path taught in advance. I will explain from the beginning.

  Here, the weaving is executed, and based on the distance measurement data as the measurement data obtained by the laser sensor LS for each sampling period, the laser sensor control device LU detects the feature point of the groove and the initial groove. The groove information such as the gap amount G is calculated, and the groove information including the gap amount G is notified to the robot controller RC.

  On the other hand, the camera control unit CCU performs image processing on data captured by the imaging camera 25. If there is a bead B, the camera control unit CCU analyzes the surplus height Cv of the bead B and notifies the surplus height Cv to the robot control unit RC.

FIG. 6 is a control flowchart executed by the CPU 20 of the robot controller RC every predetermined calculation cycle.
In S <b> 10, the CPU 20 determines whether or not the bead B is within the field of view of the imaging camera 25. If the surplus height Cv is not notified from the camera control unit CCU, it is determined as “NO”, and in S20, the CPU 20 refers to the adaptive welding condition table and determines the welding current Is based on the gap amount G. And notifies the welding power source WPS. The welding power source WPS supplies current to the wire 15 based on the welding current Is.

In next S30, the CPU 20 controls the posture of the manipulator M with the target posture determined based on the groove information on the posture of the welding torch 14, and once ends this control flowchart.
On the other hand, if there is a notification of the surplus height Cv from the camera control unit CCU in S10, the CPU 20 determines “YES”, and in S40, the CPU 20 refers to the adaptive welding condition table based on the gap amount G. Thus, the welding current Is is determined.

  In subsequent S50, the CPU 20 refers to the bead appearance adjustment table and determines (calculates) the relative current IR according to the surplus height Cv. In S60, the CPU 20 calculates (welding current Is + relative current IR) to correct the welding current, and notifies the welding power source WPS of the corrected welding current. The welding power source WPS supplies current to the wire 15 based on the corrected welding current. In S70, the CPU 20 controls the attitude of the manipulator M based on the target attitude determined based on the groove information, and this control flowchart is temporarily terminated.

Hereinafter, by performing the processing of S40 to S70 up to the welding end point, the welding current supplied to the welding torch 14 is corrected according to the surplus height Cv.
Here, since the absolute value of the relative current IR, which is the correction value, is set to be smaller as the surplus height Cv is higher, the corrected welding current is determined according to the gap amount G of the weld joint. It is converged to the welding current Is. For example, when the gap amount G continues and is the same, the welding current Is is constant. Therefore, in this state, the absolute value of the relative current IR of the correction value decreases as the surplus height Cv increases. The welding current Is + the relative current IR) is a value converged to the welding current Is. As a result, the heat input of the workpiece W increases.

  Further, for example, when the gap amount G is continuously the same, the welding current Is is constant. In this state, the absolute value of the relative current IR is set to increase as the surplus height Cv decreases, so the corrected welding current is the welding current Is determined according to the gap amount G of the weld joint. Is corrected so as to be smaller. For this reason, an increase in heat input is suppressed, and it is possible to prevent melting.

  Considering the phenomenon of burn-through, it is considered that the cause of the burn-out is that the heat capacity of the thin plate material is smaller than that of the medium-thick plate. When comparing normal welding and burn-off, it is the surplus height that shows a marked change. Since the welding current Is is set in advance so as to obtain a predetermined penetration and surplus height, the surplus height at normal time is as shown in FIG.

  However, when burn-out occurs, the gap increases to increase the welding current (command current), but the workpiece W melts more than expected and the gap rapidly increases. Then, the molten metal is gradually pulled up in the plate direction, and the surplus height is lowered. Finally, the molten metal leaks into gravity due to its own weight, and at the same time, the surplus is lost all at once (see FIG. 5).

  In this way, the melt-off does not occur suddenly, and a symptom occurs in which the welded portion gradually begins to become larger than expected and at the same time, the surplus height gradually decreases. In the present embodiment, this precursor is captured and reflected in the welding current, which is a welding condition, to prevent burn-off.

According to this embodiment, the following effects can be obtained.
(1) In the welding condition correction method for the arc welding robot of the present embodiment, the welding current Is (welding condition) is determined according to the gap amount G (groove information) of the butt joint. And it correct | amends so that it may converge to the welding current Is (welding conditions) determined according to the gap amount G of a butt joint, so that the surplus height Cv of the bead B becomes high. Further, the welding current Is (welding condition) determined in accordance with the gap amount G of the butt is corrected so that the heat input becomes smaller as the surplus height Cv of the bead B becomes lower. As a result, in the adaptive welding, it is possible to prevent melt-down.

  (2) In the welding condition correction method of the arc welding robot of this embodiment, when the surplus height Cv is within a predetermined range of 0.0 mm to 2.0 mm, the surplus height Cv is an upper limit of the predetermined range ( As the value approaches 2.0 mm), correction is made so as to converge to the welding current Is (welding conditions) determined according to the gap amount G (groove information) of the butt joint. Further, as the surplus height Cv approaches the lower limit (0.0 mm) of the predetermined range, correction is made so as to become smaller than the welding current Is (welding conditions) determined according to the gap amount G of the butt joint.

As a result, when the surplus height Cv is within a predetermined range, it is possible to prevent the melt-off in adaptive welding.
(3) The control apparatus 10 for the welding robot of the present embodiment acquires laser groove information based on measurement data (ranging data) of a laser sensor LS (measuring unit) that measures the cross-sectional shape of the weld joint. An apparatus LU (groove information acquisition means) is provided. The control device 10 includes a robot control device RC (calculation means) that calculates welding conditions based on groove information, and performs welding with the welding torch 14 of the manipulator M according to the welding conditions. Further, the control device 10 is supported by the manipulator M and acquires an image camera 25 (shape acquisition unit) that acquires the shape of the bead B formed by welding with the welding torch 14, and image data (acquisition of the image pickup camera 25). A camera control unit CCU (surplus height calculation means) that calculates the surplus height Cv of the bead B based on the data). Further, the control device 10 corrects the bead B so that it converges to the welding current Is (welding condition) determined according to the groove information of the welded joint as the surplus height Cv of the bead B increases, and the surplus height of the bead B is corrected. A robot controller RC (correction means) is provided that corrects the welding current Is determined according to the gap amount G (groove information) of the weld joint as the length Cv decreases, so that the heat input becomes smaller. As a result, by using this control device 10, when the surplus height Cv is within a predetermined range, it is possible to prevent the melt-off in adaptive welding.

  (4) Further, when the surplus height Cv is within a predetermined range of 0.0 mm to 2.0 mm, the robot controller RC increases as the surplus height Cv approaches the upper limit (2.0 mm) of the predetermined range. Then, correction is made so as to converge to the welding current Is (welding condition) determined according to the gap amount G (groove information) of the butt joint. Further, the robot controller RC becomes smaller than the welding current Is (welding condition) determined according to the gap amount G of the butt joint as the surplus height Cv approaches the lower limit (0.0 mm) of the predetermined range. Correct as follows. As a result, by using this control device 10, when the surplus height Cv is within a predetermined range, it is possible to prevent the melt-off in adaptive welding.

In addition, this invention is not limited to the said embodiment, You may comprise as follows.
In the above-described embodiment, the bead appearance adjustment table is welded so that the surplus height Cv changes as a step in accordance with the surplus height Cv in the range from the lower limit value 0.0 mm to the upper limit value 2.0 mm as an example. A relative current IR is set as a current correction value. Instead, for example, as shown in Table 4, it may be changed linearly within a predetermined range such as a range from a lower limit value of 0.0 mm to an upper limit value of 2.0 mm.

  In the predetermined range of the bead appearance adjustment table shown in Table 4, the welding current is such that the surplus height Cv changes linearly in accordance with the surplus height Cv in the range from the lower limit value 0.0 mm to the upper limit value 2.0 mm. In this example, the relative current IR is set as the correction value. As shown in the figure, in the bead appearance adjustment table, as the surplus height Cv increases, the absolute value of the relative current IR that is the correction value decreases, and as the surplus height Cv decreases, the relative current IR increases. The absolute value of is set to be large. In addition, the numerical value of the bead appearance adjustment table of Table 4 is an example, and is not limited.

○ アダプティブ溶接条件テーブルは、表１、表２では、ギャップ量Ｇと溶接電流Ｉｓとから構成しているが、開先面積と溶接電流からなるアダプティブ溶接条件テーブルとしてもよい。この場合のアダプティブ溶接条件テーブルは、開先面積が増加すると、溶接電流Ｉｓをステップ状に、或いはリニアに増加させるものとする。

In Tables 1 and 2, the adaptive welding condition table is composed of the gap amount G and the welding current Is, but may be an adaptive welding condition table including a groove area and a welding current. In the adaptive welding condition table in this case, when the groove area increases, the welding current Is is increased stepwise or linearly.

In the above-described embodiment, the imaging camera 25 is used as the shape acquisition unit. However, instead of the imaging camera 25, a laser sensor may be used.
In the above embodiment, the adaptive welding condition table for changing the welding current as the welding condition according to the gap amount G as the groove condition is set, but the adaptive welding condition table is not limited to this. .

  An adaptive welding condition table for changing the welding voltage as the welding condition according to the gap amount G as the groove condition or the groove area may be set. In this case, by referring to the adaptive welding condition table, the robot controller RC communicates a command corresponding to the gap amount G or the groove area, that is, the welding voltage to the welding power source WPS and changes the welding voltage in real time. By doing, desired welding construction can be performed, filling a gap.

  In this case, in the adaptive welding condition table, when the gap amount G or the groove area increases, the welding voltage as the welding condition increases, and when the gap amount G or the groove area decreases, the welding voltage decreases. Is set to Note that the welding voltage may be increased or decreased linearly or stepwise.

  On the other hand, in this case, the bead appearance adjustment table is set so that the absolute value of the relative voltage, which is a correction value, is expressed as a negative value as the surplus height Cv increases, and the surplus height Cv. The absolute value of the relative voltage is set to increase as the value of becomes lower. The method of increasing or decreasing the relative voltage of the correction value may be either linear or stepped.

  The robot controller RC determines the welding voltage according to the gap amount G or the groove area by referring to the adaptive welding condition table, and refers to the bead appearance adjustment table according to the surplus height Cv. The relative voltage as a correction value is determined, and the welding voltage and the relative voltage are added to correct the welding voltage so that the heat input becomes smaller.

Even in this case, it is possible to prevent the melt-down in the same manner as in the embodiment.
In addition, instead of the welding current in the adaptive welding condition table of the above embodiment, a welding speed as a welding condition may be used.

  In this case, in the adaptive welding condition table, when the gap amount G or the groove area increases, the welding speed as the welding condition decreases, and when the gap amount G or the groove area decreases, the welding speed increases. Is set to The method of increasing / decreasing the welding speed may be linear or stepped.

  On the other hand, in this case, the bead appearance adjustment table is set so that the absolute value of the relative speed, which is a correction value, is expressed as a negative value as the surplus height Cv increases. The absolute value of the relative speed is set to be smaller as the value becomes lower. The method of increasing or decreasing the relative speed of the correction value may be either linear or stepped.

  Then, the robot controller RC determines the welding speed according to the gap amount G or the groove area with reference to the adaptive welding condition table, and according to the surplus height Cv with reference to the bead appearance adjustment table. The relative speed, which is a correction value, is determined, and the welding speed is corrected by adding the welding speed and the relative speed. Then, the robot controller RC controls the manipulator M based on the corrected welding speed.

  In this case, since the absolute value of the relative speed is set to be smaller as the surplus height Cv is lower, the welding speed is corrected so that the heat input becomes smaller. As a result, similar to the above embodiment, it is possible to prevent the melt-down.

  In the configuration of the above embodiment, as the adaptive welding condition table, at least any two welding conditions among the welding current, the welding voltage, and the welding speed may be combined according to the gap amount G or the groove area. Of course. In this case, also in the bead appearance adjustment table, at least any two welding conditions among the welding current, the welding voltage, and the welding speed may be set in combination according to the surplus height.

  A sensor device control device that integrates the laser sensor control device LU and the camera control device CCU of the above embodiment is provided, and the sensor device control device provides the same features as the management of the laser sensor control device LU and the camera control device CCU. It is also possible to manage the groove information such as the height of the groove and the like. In this case, the adaptive welding condition table and the bead appearance adjustment table may be managed by the sensor device control apparatus. That is, the sensor device control apparatus may include a storage unit 23 having a first storage area 23a for storing an adaptive welding condition table and a second storage area 23b for storing a bead appearance adjustment table. The sensor device controller notifies the robot controller RC of the target position of the welding torch 14 and the target attitude of the welding torch 14 obtained from the feature points, and is obtained from the groove information and the surplus height. The welding condition may be directly notified to the welding power source WPS.

In the above embodiment, the butt joint has been described. However, it goes without saying that the present invention can also be applied to a lap joint or fillet joint welding as a weld joint.
In the above embodiment, the manipulator M is driven and controlled so that the welding torch 14 is weaved. However, the manipulator may be driven and controlled so that the welding torch 14 is along the weld line without weaving.

The block diagram of the control apparatus of the robot of one Embodiment. (A) is explanatory drawing of a tool coordinate system, (b) is a perspective view of the laser sensor LS which shows the attachment state of the laser sensor LS. The block diagram of a robot control apparatus. Explanatory drawing of the surplus height Cv of a bead. Explanatory drawing of burn-through. The flowchart which CPU of a robot control apparatus performs. The block diagram of the control apparatus of the robot of a prior art example. Explanatory drawing of groove | channel information at the time of performing image analysis based on the ranging data sampled with the laser sensor LS with respect to the lap joint. Explanatory drawing of the three-dimensional track | orbit of a welding torch. (A) is explanatory drawing of gap amount G with a fillet joint, (b) is explanatory drawing of gap amount G and groove area of a butt joint.

Explanation of symbols

10 ... Control device, 14 ... Welding torch,
20 ... CPU, 23 ... storage part (storage means),
25. Imaging camera (shape acquisition means),
Is: set current (welding current), IR: relative current (correction value),
M ... Manipulator, RC ... Robot control device (calculation means, correction means),
LU ... Laser sensor control device (groove information acquisition means), WPS ... Welding power supply,
LS ... Laser displacement sensor (measuring means)
Cv: surplus height, CCU: camera control device (surplus height calculation means).

Claims (6)

In the welding condition correction method of the automatic welding apparatus that determines the welding conditions according to the groove information of the welded joint,
As the surplus height of the bead increases, it is corrected so as to converge to the welding conditions determined according to the groove information of the weld joint,
A welding condition correction method for an automatic welding apparatus, wherein the welding condition determined in accordance with the groove information of the welded joint is corrected so that the heat input becomes smaller as the surplus height of the bead becomes lower.   The welding condition correction method for an automatic welding apparatus according to claim 1, wherein the groove information is a gap amount or a groove area. When the surplus height is within a predetermined range, the surplus height is corrected to converge to the welding conditions determined according to the groove information of the weld joint as the surplus height approaches the upper limit of the predetermined range. ,
The correction is made so that the heat input becomes smaller than the welding condition determined according to the groove information of the weld joint as the surplus height approaches the lower limit of the predetermined range. The welding condition correction method for an automatic welding apparatus according to claim 2. A groove information acquisition unit that acquires groove information based on measurement data of a measurement unit that measures a cross-sectional shape of the welded joint, and a calculation unit that calculates a welding condition based on the groove information. In an automatic welding device that performs welding with a welding torch provided in a manipulator,
Shape acquisition means for acquiring the shape of a bead formed by being welded by the welding torch while being supported by the manipulator;
Surplus height calculation means for calculating the surplus height of the bead based on the acquisition data of the shape acquisition means;
Correction is made to converge to the welding conditions determined according to the groove information of the weld joint as the surplus height of the bead increases, and according to the groove information of the weld joint as the surplus height of the bead decreases. An automatic welding apparatus comprising correction means for correcting the welding conditions determined in this way so that heat input is reduced.   The automatic welding apparatus according to claim 4, wherein the groove information is a gap amount or a groove area.   When the surplus height is within a predetermined range, the correction means converges to the welding conditions determined according to the groove information of the weld joint as the surplus height approaches the upper limit of the predetermined range. The welding conditions determined according to the groove information of the weld joint are corrected so that the heat input becomes smaller as the surplus height approaches the lower limit of the predetermined range. The automatic welding apparatus according to claim 4 or 5.

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