JP2018176164A - Laser welding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser welding device that is able to perform high quality laser welding.SOLUTION: In a seam tracking controller 30, a determination whether there is displacement between the emission position of a laser beam C emitted to a work-piece W and an actual weld line L on the work piece W is made in S18 in a laser position movement process. In a case where there is a displacement as a result of determination in S18, the Galvano mirror part 20 of a Galvano-scanner G is controlled such that the emission position of the laser beam C is moved toward the actual weld line L on the work piece W. Meanwhile, in a case where it is determined that there is no displacement as a result of determination in S18, the Galvano-mirror part 20 of the Galvano-scanner G is controlled such that the emission position of the laser beam C is moved within a predetermined range from the weld line L on the work piece W.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a laser welding apparatus for welding an object to be welded with a laser beam irradiated to an object to be welded by the laser irradiation device while moving the laser irradiation device with respect to the object to be welded by a moving device.

  There is a laser welding apparatus which performs welding by irradiating a welding object with a laser beam oscillated by a laser oscillator while moving the laser beam using a galvano scanner (for example, Patent Document 1). In such a laser welding apparatus, for example, the weld line of the object to be welded is programmed in advance by teaching, and the galvano scanner is controlled to change the irradiation position of the laser light along the programmed weld line, Perform laser welding.

  Here, the change range of the irradiation position of the laser beam by the galvano scanner is limited, and when the welding range is wide, welding can not be completed by one laser welding only by control of the galvano scanner. In addition, when the shape of the weld line and the shape of the object to be welded are complicated, the control of the galvano scanner also becomes complicated.

  Therefore, in recent years, a laser welding apparatus has been used in which a laser irradiation apparatus is mounted at the tip of a multi-axis robot that has a plurality of axes and can rotate around each axis. In this laser welding apparatus, the multi-axis robot moves the laser irradiation apparatus such that the laser light is irradiated along the welding line of the pre-programmed welding target. As a result, welding of the object to be welded can be performed over a wide range by one laser welding, and laser welding can be easily performed even if the shape of the welding line or the shape of the object to be welded is complicated.

JP, 2012-024808, A

  However, when moving a laser irradiation apparatus by a multi-axis robot, the irradiation position of a laser beam may shift from the welding line of a welding subject with the movement accuracy. In addition, when welding is performed on a plurality of welding objects having the same shape, the shape of each welding object may have some variations even if laser light is irradiated toward the welding line based on the same program. In some cases, the desired position is not irradiated with the laser beam.

  Therefore, the laser irradiation device provided at the tip of the multi-axis robot is configured by a galvano scanner, and when the irradiation position of the laser light deviates from the welding line, the irradiation position of the laser light is moved by the galvano scanner It is conceivable to eliminate the deviation. However, when the galvano scanner is driven to start moving the irradiation position of the laser light from the state where the galvano scanner is not driven (the state where the irradiation position of the laser light is not changed by the laser irradiation device), There are some cases where it is necessary to stop the irradiation of the laser beam, and in such a case, there is a problem that there is a possibility that a portion where the laser beam is not sufficiently irradiated is generated and the quality of welding may be degraded.

  The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a laser welding apparatus capable of performing high-quality laser welding.

  In order to achieve this object, a laser welding apparatus according to claim 1 comprises: a laser irradiation apparatus for irradiating a welding object with laser light; and a moving apparatus capable of moving the laser irradiation apparatus relative to the welding object; Welding the object to be welded with a laser beam irradiated to the object to be welded by the laser irradiation device while moving the laser irradiation device with respect to the object to be welded by the moving device. The moving device includes moving device control means for controlling the laser irradiation device to move along the welding line of the welding target set in advance, and the laser irradiation device is configured to Irradiation means for condensing and irradiating the object to be welded, moving means for moving the irradiation position of the laser light emitted from the irradiation means on the object to be welded, and moving means for the same Laser irradiation device control means for controlling movement of the irradiation position by the laser irradiation device control means, wherein the laser irradiation device control means shifts the irradiation line between the irradiation position of the laser beam irradiated to the object to be welded and the welding line A first movement control means for controlling the moving means to move the irradiation position to the welding line when it is judged by the judging means that there is the deviation; And second movement control means for controlling the movement means such that the irradiation position moves within a predetermined range from the welding line when the judgment means does not judge that the deviation is present.

  The laser welding apparatus according to claim 2 is the laser welding apparatus according to claim 1, wherein the second movement control means controls the movement means so that the irradiation position moves at least on the welding line. .

  The laser welding apparatus according to claim 3 is the laser welding apparatus according to claim 1 or 2, wherein the second movement control means performs the movement of the irradiation position a plurality of times by the second movement control means. The movement is controlled so that the accumulation of the movement distance becomes zero.

  The laser welding apparatus according to claim 4 is the laser welding apparatus according to any one of claims 1 to 3, wherein the second movement control means controls the irradiation position of the laser light by the control of the second movement control means. The irradiation position of the laser light is moved such that the moving speed in the direction parallel to the welding line is smaller than the moving speed of the irradiation position of the laser light by the moving device.

  A laser welding apparatus according to claim 5 is the laser welding apparatus according to any one of claims 1 to 4, wherein the laser irradiation apparatus control means is a welding preset for the moving apparatus from the moving apparatus. The second movement control means is configured to obtain the irradiation position within a predetermined range from the welding line based on the information concerning the position of the welding line acquired by the acquiring means; The moving means is controlled to move inward.

  According to the laser welding apparatus of the first aspect, the moving device moves the laser irradiation device with respect to the welding object along the welding line of the welding object set in advance by the control of the moving device control means. The laser beam is irradiated from the laser irradiation apparatus along the weld line of the object to be welded, and the object to be welded is welded at the weld line. A laser irradiation apparatus has an irradiation means which condenses a laser beam and irradiates it toward a welding object, and the irradiation position in the welding object of the laser beam irradiated from the irradiation means is a laser irradiation apparatus. It is comprised so that it can move also by the provided movement means. The movement of the irradiation position by the movement means is controlled by the laser irradiation device control means. Here, in the laser irradiation apparatus control means, it is judged by the judgment means whether there is a deviation between the irradiation position of the laser beam irradiated to the object to be welded and the welding line of the object to be welded. The moving means is controlled by the first movement control means such that the irradiation position is moved to the welding line when it is judged by the judging means that there is a deviation. On the other hand, the moving means is controlled by the second movement control means such that the irradiation position is moved within a predetermined range from the welding line of the welding object when it is not judged by the judging means that there is a deviation. Thereby, while a laser beam is always irradiated in a predetermined range from a welding line, when a shift arises between an irradiation position of a laser beam and a welding line, an irradiation position of a laser beam without stopping irradiation of a laser beam Can be returned to the weld line. Therefore, there is an effect that good quality laser welding can be performed.

  According to the laser welding device of the second aspect, in addition to the effects of the laser welding device of the first aspect, the following effects can be obtained. That is, the movement of the irradiation position of the laser beam by the second movement control means is controlled by the second movement control means so that the irradiation position moves at least on the welding line. Thereby, even if movement control by the 2nd movement control means is performed, the irradiation position of a laser beam can suppress that it deviates from a welding line, and it can be said that good quality laser welding can be performed along a welding line. effective.

  According to the laser welding device of the third aspect, in addition to the effects of the laser welding device of the first or second aspect, the following effect is exhibited. That is, the movement of the irradiation position of the laser beam by the second movement control means is controlled such that the accumulation of the movement distance becomes zero when the movement is performed a plurality of times. As a result, even if the movement control by the second movement control means is performed, the laser light irradiation position can be prevented from deviating from the position assumed by the movement device.

  According to the laser welding device of the fourth aspect, in addition to the effects of the laser welding device of any one of the first to third aspects, the following effects can be obtained. That is, the second movement control means is configured such that the movement speed of the irradiation position of the laser light in the direction parallel to the weld line by the control of the second movement control means is smaller than the movement speed of the irradiation position of the laser light by the movement device. The irradiation position of the laser beam is moved by the control of. As a result, it is possible to suppress the laser light from being irradiated to the same portion, and it is possible to perform the laser welding with good quality.

According to the laser welding device of the fifth aspect, in addition to the effects of the laser welding device of any of the first to fourth aspects, the following effects can be obtained. That is, the information on the position of the weld line set in advance with respect to the moving device is acquired by the acquisition unit of the laser irradiation device control unit.
Then, based on the information on the position of the weld line acquired by the acquisition means, the moving means is controlled by the second movement control means so that the irradiation position moves within the predetermined range from the weld line. Thereby, there is an effect that the movement amount by the second movement control means can be easily determined based on the information acquired from the movement device.

BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows schematically the structure of the laser welding apparatus which is one Embodiment of this invention. It is the schematic which showed the internal structure of the galvano scanner and the seam tracking head roughly. It is a block diagram showing the electric composition of a seam tracking controller. (A) shows an example of the moving position of the laser beam irradiated to the workpiece, which is moved by the galvano scanner when it is not determined that there is a deviation between the laser beam irradiated to the workpiece and the welding line on the actual workpiece (B) is a schematic view schematically showing the case where the laser irradiation position by the galvano scanner is moved in the example shown in (a) while moving the galvano scanner by the multi-axis robot It is the figure which showed the time change of the irradiation position of a laser beam. (A) is another movement position of the laser beam irradiated to the workpiece, which is moved by the galvano scanner when it is not determined that there is a difference between the laser beam irradiated to the workpiece and the welding line on the actual workpiece FIG. 8B is a schematic view schematically showing an example, and while moving the galvano scanner by the multi-axis robot, moving the irradiation position of the laser beam by the galvano scanner in the example shown in FIG. It is the figure which showed the time change of the irradiation position of a laser beam at the time of having. It is a flowchart which shows the laser position movement process performed by CPU of a seam tracking controller.

  Hereinafter, embodiments of the present invention will be described with reference to the attached drawings. First, a schematic configuration of a laser welding apparatus T according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic view schematically showing the configuration of the laser welding apparatus T. As shown in FIG.

  The laser welding apparatus T is an apparatus that performs welding of the workpiece W while irradiating the workpiece W (hereinafter simply referred to as “workpiece”) with the laser light C along the welding line L. As shown in FIG. 1, the laser welding apparatus T includes at least a laser oscillator 10 for oscillating a laser beam C, a galvano scanner G and a seam tracking head S which are laser irradiation apparatuses, and a multi-axis robot R which is a moving apparatus. Configured

  The laser beam C oscillated by the laser oscillator 10 is transmitted by the optical fiber 11 and taken into the galvano scanner G from the fiber adapter 12 provided at one end of the optical fiber 11. The galvano scanner G adjusts the irradiation position in the direction indicated by the two-axis D2 when irradiating the taken-in laser light C toward the workpiece W.

  The seam tracking head S is attached to the galvano scanner G. The seam tracking head S determines the deviation of the irradiation position of the laser beam C irradiated to the workpiece W with respect to the welding line L, controls the galvano scanner G, and the irradiation position of the laser beam C becomes on the welding line L Is a device for performing position correction.

  The galvano scanner G is attached to the tip of the multi-axis robot R. The multi-axis robot R, for example, is capable of rotating the galvano scanner G attached to the tip, around each axis of the three axes D1. As a result, welding of the workpiece W can be performed over a wide range by one laser welding, and laser welding can be easily performed even if the shape of the welding line L or the shape of the workpiece W is complicated. it can. The multi-axis robot R does not have to have three axes at the center of rotation, as long as the galvano scanner G can rotate around one or a plurality of axes.

  A teach pendant 23 is connected to the multi-axis robot R. The teaching pendant 23 is used to set the operation of the laser welding apparatus T, teach the welding line L of the workpiece W (program), etc., for the robot controller 40 (see FIG. 2) that controls the multi-axis robot R. It plays a role as an input means and also plays a role as a display means for displaying the operating state of the laser welding apparatus T. Under the control of the robot controller 40, the multi-axis robot R moves the galvano scanner G such that the laser beam C is irradiated to the work W along the weld line L taught by the teaching pendant 23. The robot controller 40 is incorporated in the multi-axis robot R.

  Next, with reference to FIG. 2, the internal configurations of the galvano scanner G and the seam tracking head S will be described. FIG. 2 is a schematic view schematically showing the internal configuration of the galvano scanner G and the seam tracking head S. As shown in FIG.

  The galvano scanner G includes a collimator lens 13, a reflection mirror 14, a half mirror 15, a focusing lens 16, a galvano mirror unit 20, an X axis displacement motor 20 a, a Y axis displacement motor 20 b, an fθ lens 21, and a galvano scanner controller 18. There is. The seam tracking head S also includes an imaging device 17, an imaging device rotation motor 22, and a seam tracking controller 30.

  Specifically, in the galvano scanner G, the collimator lens 13 is disposed on the output side of the fiber adapter 12. The laser beam C oscillated by the laser oscillator 10 and transmitted through the optical fiber 11 and irradiated from the fiber adapter 12 is collimated by the collimator lens 13. The laser beam C collimated by the collimator lens 13 is reflected by the reflection mirror 14 toward the galvano mirror unit 20, and is transmitted through the half mirror 15 provided between the reflection mirror 14 and the galvano mirror unit 20. , And the galvano mirror unit 20.

  The galvano mirror unit 20 adjusts the irradiation position when irradiating the laser beam C toward the workpiece W, and is configured by a pair of reflection mirrors (galvano mirrors) not shown.

  One of the pair of reflection mirrors is connected to the X-axis displacement motor 20a. By driving the X-axis displacement motor 20a, the reflection angle of the reflection mirror to be connected is changed, and the irradiation position of the laser light C with respect to the work W can be displaced in the X-axis direction. The other of the pair of reflection mirrors is connected to the Y-axis displacement motor 20b. By driving the Y-axis displacement motor 20b, the reflection angle of the reflection mirror to be connected is changed, and the irradiation position of the laser light C with respect to the workpiece W can be displaced in the Y-axis direction. Therefore, the galvano scanner G can adjust the irradiation position of the laser beam C irradiated with respect to the workpiece | work W by driving the X-axis displacement motor 20a and the Y-axis displacement motor 20b.

  The fθ lens 21 is disposed on the output side of the galvano mirror unit 20. The laser beam C directed to a desired irradiation position by the galvano mirror unit 20 is condensed at the irradiation position of the work W by the fθ lens 21. In place of the fθ lens 21, a lens that moves in the Z-axis direction by the Z-axis displacement motor is installed in front of the X-axis displacement motor 20 a and the Y-axis displacement motor 20 b so that light is collected at the irradiation position of the work W May be

  The light I reflected from the work W by the laser light C and the other light passes through the fθ lens 21 and is reflected by the galvano mirror unit 20 in the opposite direction to the laser light C. Then, the light I is reflected by the half mirror 15 and is input to the imaging device 17 of the seam tracking head S. A focusing lens 16 is disposed between the half mirror 15 and the imaging device 17, and the light I reflected from the workpiece W by the focusing lens 16 is displayed on the imaging device 17 as an image representing a welding surface of the workpiece W. It is imaged.

  The imaging device 17 is configured by, for example, a charge coupled device (CCD) image sensor, a complementary MOS (CMOS) image sensor, or the like. The image formed on the imaging device 17 is decomposed into pixels arranged in a two-dimensional array in the imaging device 17, and the intensity of the light input is converted into an electrical signal for each pixel, whereby imaging is performed. It will be. The electrical signal converted for each pixel by the imaging device 17 is output to the seam tracking controller 30 by raster scan.

  An imaging element rotation motor 22 is connected to the imaging element 17. When the image pickup device rotation motor 22 is driven by the seam tracking controller 30, the image pickup device 17 is rotated. Thereby, the direction of the image captured by the imaging element 17 can be rotated.

  The seam tracking controller 30 controls the entire laser welding apparatus T in cooperation with a robot controller 40 provided in the multi-axis robot R. The seam tracking controller 30 communicates with the robot controller 40 via the galvano scanner controller 18 of the galvano scanner G.

  When teaching (program) the weld line L of the work W is performed by the teach pendant 23 connected to the robot controller 40, a display device (not shown) provided or connected to the seam tracking controller 30, or a teach The welding surface of the workpiece W imaged by the imaging device 17 is displayed on a display device (not shown) provided on the pendant 23. The user sets the welding line L on the workpiece W while teaching the welding line L while looking at the welding surface of the workpiece W displayed on the display device.

  At this time, the seam tracking controller 30 detects a feature point from the image of the work W captured by the imaging device 17 and displays on the display device such that the weld line L of the work W is set based on the feature point. Support the user through the displayed image, and determine whether to accept the operation of the teach pendant 23.

  Information indicating the position of the weld line L of the workpiece W taught by the teaching pendant 23 is transmitted from the robot controller 40 to the seam tracking controller 30 via the galvano scanner controller 18 and is provided in the seam tracking controller 30 (RAM ( It is stored in Random Access Memory) 33 (see FIG. 3).

  In addition, the seam tracking controller 30 detects the positions of the characteristic points detected from the image of the workpiece W captured by the imaging device 17 during the welding of the workpiece W (ie, the welding line L of the actual workpiece W). The displacement amount between the position (a) and the position of the welding line L of the taught work W (the position of the laser light C irradiated to the work W) is detected. Then, the seam tracking controller 30 determines whether there is a deviation between the laser beam C irradiated to the workpiece W and the welding line L of the actual workpiece W, based on the detected displacement amount.

  If the seam tracking controller 30 determines that there is a deviation between the laser beam C irradiated to the workpiece W and the weld line L of the actual workpiece W, the feature detected from the image of the workpiece W captured by the imaging device 17 The irradiation position of the laser beam C on the position of the feature point of the detected work W (the actual weld line L of the work W) based on the deviation between the position of the point and the position of the welding line L of the taught work W The position correction amount (moving amount for position correction) of the irradiation position of the laser beam C is calculated so that The calculated position correction amount is included in the movement command of the irradiation position of the laser light C, and is transmitted to the galvano scanner controller 18 of the galvano scanner G.

  On the other hand, if it is not determined that there is a difference between the laser beam C irradiated to the workpiece W and the welding line L of the actual workpiece W, the seam tracking controller 30 applies the irradiation position of the laser beam C irradiated to the workpiece W However, the movement amount is included in a movement command of the irradiation position of the laser light C so as to move within a predetermined range from the weld line L of the workpiece W and transmitted to the galvano scanner controller 18.

  The galvano scanner controller 18 drives the X axis displacement motor 20a and the Y axis displacement motor 20b connected to the galvano mirror unit 20 so that the laser light C is irradiated to a desired position on the welding surface of the workpiece W. It is a thing.

  The galvano scanner controller 18 controls the seam tracking controller 30 to emit the laser beam C transmitted when it is determined that the laser beam C irradiated to the workpiece W deviates from the weld line L of the actual workpiece W. When receiving the movement command of the position, the X-axis displacement motor 20a and the Y-axis displacement motor 20b are driven based on the position correction amount included in the movement command, and the position of the feature point of the detected workpiece W (actual workpiece W The irradiation position of the laser beam C is adjusted so that the laser beam C is irradiated to the welding line L). Thereby, the irradiation position of the laser beam C is corrected to be on the welding line L of the actual workpiece W.

  In addition, the galvano scanner controller 18 controls the seam tracking controller 30 to transmit the laser beam C when it is not determined that there is a difference between the laser beam C irradiated to the workpiece W and the weld line L of the actual workpiece W. When receiving the irradiation position movement command, the X-axis displacement motor 20a and the Y-axis displacement motor 20b are driven based on the movement amount included in the movement command.

  The galvano scanner controller 18 is connected to the laser oscillator 10, and instructs the laser oscillator 10 to turn on / off the oscillation of the laser light C based on an instruction from the seam tracking controller 30.

  For example, when the galvano scanner controller 18 receives an instruction to move the irradiation position of the laser light C from the seam tracking controller 30, the galvano scanner controller 18 drives the galvano mirror unit 20 to move the irradiation position of the laser light C while moving the laser light In order to irradiate C to the work W, the laser oscillator 10 turns on the oscillation of the laser light C. At this time, the galvano scanner controller 18 causes the laser oscillator 10 to continuously output the laser light C even after the irradiation position of the laser light C is moved to a desired position based on the movement command. The oscillation of the laser beam C is kept on.

  Here, when the galvano mirror unit is driven to start moving the irradiation position of the laser beam from a state where the galvano mirror unit is not driven (a state where the irradiation position of the laser beam by the galvano scanner is not changed) Once, it is necessary to stop the irradiation of the laser beam, and in this case, there is a problem that a portion where the laser beam is not sufficiently irradiated is generated to deteriorate the quality of the laser welding.

  On the other hand, in the laser welding apparatus T, according to the movement command from the seam tracking controller 30, the laser beam C is controlled to be irradiated while being constantly moved from the weld line L within the predetermined range, When the welding line L deviates from the welding line L, the irradiation position of the laser light C can be returned to the welding line L without stopping the irradiation of the laser light C. Therefore, good quality laser welding can be performed.

  Next, the detailed configuration of the seam tracking controller 30 will be described with reference to FIG. FIG. 3 is a block diagram showing the electrical configuration of the seam tracking controller 30. As shown in FIG. The seam tracking controller 30 includes a central processing unit (CPU) 31, a read only memory (ROM) 32, and a RAM 33, which are connected via a bus line 34. In addition to the imaging device 17, the imaging device rotation motor 22, and the galvano scanner controller 18, the display unit (not shown) is connected to the bus line 34. As described above, the robot controller 40 is connected to the galvano scanner controller 18, and the teach pendant 23 is connected to the robot controller 40.

  The CPU 31 is an arithmetic device that controls the laser welding device T in accordance with a program stored in the ROM 32. The ROM 32 is a non-rewritable nonvolatile memory for storing programs executed by the CPU 31, fixed value data, and the like. The ROM 32 at least stores moving point A data 32 a and moving point B data 32 b as fixed value data.

  The RAM 33 is a rewritable volatile memory, and temporarily stores various data when the CPU 31 executes a program. The RAM 33 includes at least image data 33a, teaching data 33b, current welding line data 33c, current spot point data 33d, feature point data 33e, shift amount data 33f, position correction amount data 33g, rotation amount data 33h and movement point flag 33i. Remember.

  The moving point A data 32 a and the moving point B data 32 b are information indicating the moving position of the irradiation position of the laser light C with respect to the work W using the galvano scanner G. As described above, the seam tracking controller 30 determines that the laser beam C irradiated to the workpiece W does not deviate from the welding line L of the actual workpiece W, the laser beam C irradiated to the workpiece W The galvano scanner G is controlled such that the irradiation position moves within a predetermined range from the weld line L of the workpiece W. The movement position is indicated by movement point A data 32a and movement point B data 32b.

  Here, referring to FIGS. 4 and 5, the work performed by galvano scanner G when it is not determined that there is a difference between laser beam C irradiated to work W and welding line L in actual work W. The movement position of the laser beam C irradiated to W will be described. In the description of FIGS. 4 and 5, the movement of the laser beam C performed by the galvano scanner G in this case is simply referred to as the movement of the laser beam C by the galvano scanner G or the like.

  FIG. 4A is a schematic view schematically showing an example of the movement position, and the surface (welding surface) of the work W to which the laser light C is irradiated is viewed from the side to which the laser light C is irradiated. It is the figure which looked at. In FIG. 4A, for convenience of explanation, assuming that the laser beam C is not moved by the galvano scanner G, the origin O is set at a position on the welding line L to which the laser beam C is irradiated, and welding is performed. After setting the x-axis along the line L, the y-axis is set in a direction perpendicular to the x-axis on the surface of the work W on which the welding line L is set, and the work on which the welding line L is set The z axis is set in the direction perpendicular to the surface of W (welding surface). The positive direction and the negative direction of each axis may be appropriately determined in each axis.

In the example shown in FIG. 4 (a) is carried out by the galvanometer scanner G, the movement of the laser beam C is irradiated to the workpiece W, around the origin O, in the positive direction of the x-axis by the moving distance x _A from the origin O It is made to travel between the point A which is separated and the point B which is separated from the origin O by the moving distance x _{B in} the negative direction of the x-axis. The information for specifying the point A is stored in the ROM 32 as the movement point A data 32a, and the information for specifying the point B as the movement point B data 32b.

  Here, the x-axis is an axis set along the welding line L as described above. That is, in the example shown in FIG. 4A, the workpiece W is performed by the galvano scanner G when it is not determined that there is a difference between the laser beam C irradiated to the workpiece W and the weld line L of the actual workpiece W The movement of the laser beam C applied to the laser is performed on the weld line L. Thereby, even if the movement is performed, it is possible to suppress the laser light C from coming off the welding line L, and it is possible to perform laser welding with good quality along the welding line L.

When welding line L is a curve, it moves along point of welding line L in a positive direction at point _A separated from origin O by moving distance x A and in a negative direction of x axis from origin O Control is performed so as to travel between the point B separated by a distance x _B. Thereby, even if welding line L is a curve, it can control that laser beam C separates from welding line L in the movement concerned.

  The seam tracking controller 30 is information indicating the position of the weld line L of the work W taught by the teach pendant 23, and determines the position of the weld line L based on the teaching data 33b stored in the RAM 33, and the judgment The amount of movement to point A or point B is calculated from the position of welding line L and movement point A data 32a or movement point B data 32b. Thereby, the movement amount of the laser beam C by the galvano scanner G can be easily determined.

  Next, in FIG. 4B, while moving the galvano scanner G by the multi-axis robot R, in the example shown in FIG. 4A, moving the irradiation position of the laser light C by the galvano scanner G It is the figure which showed the time change of the irradiation position of the laser beam C. FIG. In FIG. 4B, the irradiation position x of the laser light C on the x axis shown in FIG. 4A is shown as the vertical axis, and the time t is shown as the horizontal axis. In addition, the broken line shown in FIG. 4B assumes that the movement of the laser light C by the galvano scanner G is not performed, and temporally the irradiation position of the laser light C by the movement of the galvano scanner G by the multi-axis robot R Change is shown. In FIG. 4B, it is assumed that there is no case where it is determined that there is a deviation between the laser beam C irradiated to the workpiece W and the welding line L of the actual workpiece W.

Here, in the example shown in FIG. 4 (a), in the movement of the laser beam C by the galvano scanner G, it is set so that the moving distance x _A and the moving distance x _B is equal to the distance. Thus, when a plurality of movements of the movement are performed, the accumulation of the movement distance is zero. Therefore, as shown in FIG. 4B, even if the galvano scanner G performs the movement, the irradiation position of the laser light C is assumed to be the irradiation position of the laser light C assumed based on the movement of the multi-axis robot R It is possible to suppress the deviation from the position shown by the broken line).

  In the movement of the laser light C by the galvano scanner G in the example shown in FIG. 4A, the movement speed of the laser light C in the x-axis direction is the movement of the laser light C by the movement of the galvano scanner G by the multi-axis robot R It is done to be less than the speed. As a result, as shown in FIG. 4B, it is possible to suppress that the laser light C is irradiated to the same place (the time when the laser light C is irradiated to the irradiation position x is plural times), and the laser of good quality It can do welding.

  On the other hand, FIG. 5A is a schematic view schematically showing another example of the moving position of the laser beam C by the galvano scanner G, in which the surface of the work W to which the laser beam C is irradiated ( It is the figure which looked at the welding surface from the side to which the laser beam C is irradiated. In FIG. 5A, for convenience of explanation, the origin O, the x axis, the y axis, the z axis, and the positive direction and the negative direction of each axis are set as in FIG. 4A.

In the example shown in FIG. 5A, the workpiece W is irradiated, which is performed by the galvano scanner G when it is not determined that there is a difference between the laser beam C irradiated to the workpiece W and the welding line L in the actual workpiece W the movement of the laser beam C which is, around the origin O, and a point distant from the origin O by the movement distance y _a in the positive direction of the y-axis, in the negative direction of the y-axis by the moving distance y _B from the origin O away It moves between the point B and the other. The information for specifying the point A is stored in the ROM 32 as the movement point A data 32a, and the information for specifying the point B as the movement point B data 32b.

  Also in the example shown in FIG. 5A, the seam tracking controller 30 is information indicating the position of the weld line L of the workpiece W taught by the teaching pendant 23, and based on the teaching data 33b stored in the RAM 33. The position of welding line L is determined, and the amount of movement to point A and point B is calculated from the determined position of welding line L and moving point A data 32a and moving point B data 32b. Thereby, the movement amount of the laser beam C by the galvano scanner G can be easily determined.

  Next, in FIG. 5B, while moving the galvano scanner G by the multi-axis robot R, in the example shown in FIG. 5A, moving the irradiation position of the laser light C by the galvano scanner G It is the figure which showed the time change of the irradiation position of the laser beam C. FIG. In FIG. 5B, the irradiation position y of the laser light C on the y axis shown in FIG. 5A is shown as the vertical axis, and the time t is shown as the horizontal axis. In addition, in FIG.5 (b), the welding line L exists in the irradiation position y in the place of "0" in arbitrary time t. Further, in FIG. 5B, it is assumed that there is no case where it is determined that there is a deviation between the laser beam C irradiated to the workpiece W and the welding line L of the actual workpiece W.

Here, in the movement of the laser light C by the galvano scanner G in the example shown in FIG. 5A, the movement distance y _A and the movement distance y _B are in a predetermined range from the welding line L (welding line L Is set to be in the range of y _L or less). Here, the distance y _L or less in the range of from the welding line L, when considering the spot diameter of the laser beam C, if it is irradiated the laser beam C is in that range, substantial laser beam C is the weld line L It is the range which can be substantially identified with what was irradiated to. Thereby, even if movement of laser beam C by galvano scanner G is performed, it can control that laser beam C separates from welding line L, and good quality laser welding can be performed along welding line L.

Further, a moving distance y _A and the moving distance y _B is set to be equal distance. Thus, when a plurality of movements of the movement are performed, the accumulation of the movement distance is zero. Thereby, as shown in FIG. 5B, even if the movement by the galvano scanner G is performed, the irradiation position of the laser light C is assumed to be the irradiation position of the laser light C based on the movement of the multi-axis robot R. It can be suppressed that the irradiation position y deviates from zero.

  In the present embodiment, the moving point A data 32a and the moving point B data 32b are stored in the ROM 32, but these are stored in the rewritable non-volatile memory (for example, flash memory, FeRAM, etc.) The positions of the point A and the point B may be changeable by Alternatively, a plurality of combinations of point A specified by the moving point A data 32a and point B specified by the moving point B data 32b may be prepared, and one combination may be selected by the user from among them.

  Returning to FIG. 3, the description will be continued. The image data 33 a is RAW data of an image captured by the imaging device 17. When the electric signal (analog signal) of each pixel picked up by the image pickup element 17 is outputted by raster scan while being amplified, it becomes an 8-bit digital value by an A / D converter (not shown) for each pixel. It is converted. The RAW data is raw data output from the A / D converter for each pixel, and is stored in the RAM 33 as image data 33a. The resolution of the A / D converter is not necessarily 8 bits, and an A / D converter having an arbitrary resolution such as a 10-bit A / D converter can be used.

  The image data 33a stored in the RAM 33 is used for display on a display device (not shown) after being subjected to predetermined image processing when teaching the welding line L of the workpiece W. Thereby, the welding surface of the workpiece W imaged by the imaging device 17 is displayed on the display device.

  Further, the image data 33a stored in the RAM 33 is used to detect a plurality of feature points from the planned welding portion included in the work W when teaching the welding line L of the work W. The detected feature points are used to combine and display an image indicating the position of the feature points on the welding surface of the workpiece W displayed on the display device.

  In addition, when the user teaches the welding line L of the work W, it is determined whether or not the taught welding line L is set based on the detected feature points, and based on the detected feature points Only when it is determined that the setting has been made, welding line L of workpiece W taught by the user is accepted. If it is determined that the welding line L taught by the user is not set based on the detected feature points, the user is again prompted to teach the welding line L.

  Thereby, the user can be assisted to set the welding line L in the work W based on the detected feature point.

  Further, the image data 33a stored in the RAM 33 is included in the predetermined area of the work W even when the work W is irradiated with the laser light C (that is, when welding by the laser light C is performed). It is used to detect a plurality of feature points from the welding line L to be welded, and to detect the position of the welding line L already welded at that time and the irradiation position of the laser beam C at that time. Is also used.

  The teaching data 33 b is data indicating the position of the welding line L of the workpiece W taught by the user. When the user teaches the welding line L of the work W by the teaching pendant 23, positional information of the welding line L is transmitted from the teaching pendant 23 to the seam tracking controller 30. In the CPU 31, the taught welding line L is detected by judging whether or not the taught position of the welding line L substantially matches the position of the feature point detected based on the image data 33a. It is determined whether or not it is set based on the feature points. When it is determined that the taught weld line L is set based on the detected feature points, the positional information of the weld line L of the workpiece W transmitted from the teach pendant 23 is stored in the RAM 33 as the teaching data 33 b. Be done.

  The present weld line data 33c is detected from the image data 33a captured during the period when the workpiece W is being irradiated with the laser beam C (that is, during the period when welding by the laser beam C is being performed), Are data showing the position of the weld line L already welded. When the weld line L already welded is detected from the image data 33a captured during the period, the CPU 31 stores the position information in the RAM 33 as the present weld line data 33c.

  The current spot point data 33 d is detected from the image data 33 a captured during the period in which the workpiece W is being irradiated with the laser light C (ie, in the period in which welding by the laser light C is performed) It is data which show the position of the irradiation position of the laser beam C in. When the irradiation position of the laser light C is detected by the CPU 31 from the image data 33a captured during the period, the position information is stored in the RAM 33 as current spot point data 33d.

  A plurality of feature point data 33e are detected from image data 33a captured during a period in which the workpiece W is irradiated with the laser light C (that is, during a period in which welding by the laser beam C is performed) Data indicating the position of the feature point of When a plurality of feature points are detected from the image data 33a captured during the period by the CPU 31, the position information of each is stored in the RAM 33 as feature point data 33e.

  The deviation amount data 33f is data indicating the deviation amount between the position of the feature point detected from the image of the workpiece W indicated by the feature point data 33e and the taught welding line L indicated by the teaching data 33b. During welding of the workpiece W, the position of the feature point detected from the image data 33a of the workpiece W captured by the imaging device 17 by the CPU 31 and the position of the welding line L of the taught workpiece W The amount of deviation is detected. The detected deviation amount is stored in the RAM 33 as deviation amount data 33f.

  The position correction amount data 33g is data indicating a correction amount (position correction amount) of position correction to be performed on the position of the welding line L of the taught work W indicated by the teaching data 33b. It is determined that there is a deviation between the laser beam C irradiated to the work W and the welding line L of the actual work W based on the deviation detected by the CPU 31 (the deviation shown by the deviation data 33f) In this case, the irradiation position of the laser light C is at the position of the feature point of the work W indicated by the feature point data 33e from the irradiation position of the laser light C at that time indicated by the current spot point data 33d on the work W The CPU 31 calculates a position correction amount for correcting the position of the weld line L of the taught work W so as to move. The position correction amount is stored in the RAM 33 as position correction amount data 33g. The position correction amount stored in the position correction amount data 33 g is included in the movement command of the irradiation position of the laser light C, and is transmitted to the galvano scanner controller 18 of the galvano scanner G.

  Here, the welding line L of the taught work W is originally set along the feature points of the work W. Therefore, the taught work W such that the irradiation position of the laser light C moves to the position of the feature point of the work W detected while irradiating the work W with the laser light C (that is, during welding of the work W) By correcting the position of the welding line L, the desired position is irradiated with the laser light C even if the work W moves during welding or if there is a variation in the shape among a plurality of works W of the same shape. be able to. Therefore, laser welding can be performed at a desired position.

  The rotation amount data 33 h is data indicating a rotation amount when the imaging device 17 is rotated by the imaging device rotation motor 22. The seam tracking controller 30 captures an image of the workpiece W captured by the imaging device 17 such that the arrangement of the plurality of feature points included in the workpiece W is not parallel to the horizontal scanning direction of the imaging device 17 The element 17 is rotated. At this time, the CPU 31 sets a rotation amount for rotating the imaging element 17 in the rotation amount data 33h, and the imaging element rotation motor so that the imaging element 17 is rotated by the rotation amount indicated by the rotation amount data 33h. Drive 22

  Here, when the imaging element 17 rotates, the positional relationship between each pixel of the imaging element 17 and the work W also rotates. Therefore, the CPU 31 checks the rotation amount data 33 h when reading RAW data of each pixel from the image data 33 a captured by the imaging device 17, and based on the rotation amount of the imaging device 17, the RAW data of the read pixel is It is grasped at which position of the work W the raw data is.

  The movement point flag 33i is a laser applied to the workpiece W, which is performed by the galvano scanner G when it is not determined that there is a difference between the laser beam C irradiated to the workpiece W and the weld line L of the actual workpiece W The movement of the light C is a flag for indicating to which of the point A and the point B the movement point (see FIG. 4A or FIG. 5A) is to be moved. Specifically, it indicates moving to the point A when the moving point flag 33i is on, and indicates moving to the point B when the moving point flag 33i is off.

  The movement point flag 33i is set to "on" as an initial value when the seam tracking controller 30 is powered on. If it is not determined that there is a difference between the laser beam C irradiated to the workpiece W and the weld line L of the actual workpiece W, the CPU 31 causes the workpiece W to be moved by the galvano scanner G if the moving point flag 33i is on. In order to move the laser light C to be irradiated toward the point A, a movement command of the irradiation position of the laser light C including the movement amount is transmitted to the galvano scanner controller 18, and the movement point flag 33i is Set to "Off". On the other hand, when it is not determined that there is a difference between the laser beam C irradiated to the workpiece W and the welding line L of the actual workpiece W, the CPU 31 works the workpiece by the galvano scanner G if the moving point flag 33i is off. In order to move the laser light C irradiated to W toward the point B, a movement command of the irradiation position of the laser light C including the movement amount is transmitted to the galvano scanner controller 18, and the movement point flag 33i Set to "on".

  Thus, the movement point flag 33i is set to "off" when movement control toward the point A is performed by being "on" and to the point B by that it is "off". It is set to "on" when directed movement control is performed. As a result, when it is not determined that there is a difference between the laser beam C irradiated to the workpiece W and the weld line L in the actual workpiece W, the laser beam C irradiated to the workpiece W performed by the galvano scanner G The movement can be passed back and forth between point A and point B.

  Then, with reference to FIG. 6, the laser position movement process performed by CPU31 of the seam tracking controller 30 is demonstrated. FIG. 6 is a flowchart showing the laser position moving process. The laser position moving process is a process of controlling the galvano scanner G to move the irradiation position of the laser light C. This process is started simultaneously with the start of welding of the workpiece W, and continues to be performed until the welding is completed.

  In the position correction process, first, an imaging element rotation process is performed (S11). In the image sensor rotation process (S11), in the image of the work W captured by the image sensor 17, the image sensor in which the arrangement of the plurality of feature points included in the work W is not parallel to the horizontal scanning direction of the image sensor 17. The rotation amount 17 is set to the rotation amount data 33h. Then, the image pickup device rotation motor 22 is driven such that the image pickup device 17 is rotated by the rotation amount set in the rotation amount data 33 h. Whether or not the arrangement of a plurality of feature points is not parallel to the horizontal scanning direction of the imaging device 17 depends on the position of each feature point stored in the feature point data 33 e (from the image of the workpiece W captured most recently) The determination is made based on the information indicating the position of the detected feature point.

  Here, the reason why the imaging device 17 is rotated so that the arrangement of the plurality of feature points is not parallel to the direction of the horizontal scanning of the imaging device 17 is as follows. In general, image processing on an image captured by the imaging device 17 is performed in the order of pixels read by horizontal scanning of the imaging device 17 based on raster scan. Under such circumstances, if a plurality of feature points of the work W are arranged in parallel with the horizontal scanning direction of the imaging device 17, if image processing is not performed across a plurality of scanning lines, it is a feature point. It can not be determined whether there is any, and it takes time to detect feature points. On the other hand, since the imaging device 17 is rotated by the imaging device rotation motor 22 so that the plurality of feature points of the workpiece W are not parallel to the horizontal scanning direction of the imaging device 17, the scanning lines straddle the plurality of scanning lines. Even if image processing is not performed, feature points can be detected. Therefore, the time required for the detection can be shortened.

  Next, an image capture process is performed (S12). In the image capturing process (A12), the imaging of the workpiece W is instructed to the imaging device 17, and the image data of each pixel output from the imaging device 17 by raster scan and converted into digital values by the A / D converter is It stores in the image data 33a.

  Further, in this image capture process (S12), the image data of the workpiece W captured by the imaging device 17 with the exposure time shortened and the image data of the workpiece W captured with the imaging device 17 with the exposure time extended And are taken in continuously. The reason for capturing two image data having different exposure times is as follows. When the exposure time is long, the reflection of the light of high intensity of the laser light C causes the white light in the vicinity of the irradiation position of the laser light C to fly out, and detection of the irradiation position of the laser light C and its irradiation position It becomes impossible to detect feature points included in the workpiece W and the weld line L already welded.

  On the other hand, when the exposure time is shortened and an image is captured without overexposure near the irradiation position of the laser light C, the area far from the irradiation position of the laser light C is blacked out, and the work W in that area It becomes impossible to detect the feature points included in the above and the weld line L already welded. Therefore, by taking in two image data with different exposure times, image data with a short exposure time is used near the position irradiated with the laser light C, and a region far from the position irradiated with the laser light C Can reliably detect the irradiation position of the laser beam C, detect the feature points included in the workpiece W, and detect the weld line L which has already been welded, using image data with a long exposure time.

  Next, weld line detection processing is performed (S13). In the welding line detection process (S13), the welding line L already welded is detected by image processing from the two image data 33a fetched in S12, and the position information is stored in the RAM 33 as current welding line data 33c. .

  Next, a laser spot detection process is performed (S14). In the laser spot detection process (S14), the current irradiation position (the position of the spot point) of the laser light C is subjected to image processing using the image data 33a having a short exposure time among the two image data 33a captured in S12. The position information is stored in the RAM 33 as current spot point data 33 d. Since the image data 33a having a short exposure time is used to detect the current irradiation position of the laser light C, the area near the irradiation position of the laser light C is not whitened. Therefore, the present irradiation position of the laser beam C can be accurately detected from the image data 33a.

  Next, window setting processing is executed (S15). In the window setting process (S15), a rectangular area (window) for detecting feature points present in the workpiece W is set in the image data 33a captured in S12. Specifically, from the current irradiation position of the laser light C detected by the process of S14, a range of a predetermined size at a position separated by a predetermined distance in the moving direction of the laser light C by the multi-axis robot R Is set as an area (window) for detecting feature points of the workpiece W. From the current irradiation position of the laser beam C detected by the process of S14, the scanning line of the N-th (N is a natural number) image sensor 17 is directed in the moving direction of the laser beam C by the multi-axis robot R. A region up to the scanning line of the M-th (M is a natural number and M> N) imaging element 17 may be set as a region (window) for detecting a feature point of the workpiece W.

  Also, the shape of the region (window) does not have to be rectangular, and the shape may be arbitrary. For example, as the shape of the region (window), a parallelogram may be set by the process of S15. In this case, of the four sides of the parallelogram, the inclination of two parallel sides may be substantially parallel to the inclination of the welding line L taught by the user. Further, from the image data 33a captured by the process of S12, a welding line L to be welded is detected from the image data 33a, and a parallelogram whose inclination of two parallel sides is substantially parallel to the inclination of the welding line L to be welded is An area (window) may be set. As a result, since it is possible to suppress that the region (window) for detecting the feature points of the work W is set to be extra wide, the time taken to detect the feature points can be shortened, and the possibility of false detection is low. It can be suppressed.

  Also, as the shape of the region (window), a shape in which a plurality of rectangles are arranged around the taught welding line L or around the welding line L to be welded determined from the image data 33a is set May be Also by this, it is possible to suppress that the region (window) for detecting the feature points of the work W is set to be extra wide, so the time taken to detect the feature points can be shortened, and the possibility of false detection It can be kept low.

  Furthermore, the size of the area (window) may be changed according to the place (center, end, etc. of the work W) in the work W in which the area (window) is set. Thereby, if the place in the work W of the set area (window) is the central part of the work W, the size of the area (window) is enlarged and the feature points are detected by detecting many feature points. The displacement amount between the position of and the position of the welding line L of the work W taught by the user can be detected more accurately. On the other hand, if the place in the work W of the set area (window) is the end of the work W, the size of the area (window) can be reduced to suppress false detection of the feature point by the end. .

  Next, feature point detection processing is executed (S16). In the feature point detection process (S16), from the two image data 33a taken in by the process of S12, the welding line L of the workpiece W to be welded which is included in the area (window) set by the process of S15. A plurality of feature points are detected from the weld line L. Here, in the area (window), for the area close to the current irradiation position of the laser light C detected by the process of S14, the feature point is detected using the image data 33a having a short exposure time. Further, in an area (window) where the current irradiation position of the laser light C detected by the process of S14 is far, the feature point is detected using the image data 33a having a long exposure time. As a result, even if the area (window) is widely set to an area far from the area near the current irradiation position of the laser light C, the positions of the feature points present in the area (window) can be detected with certainty.

  Next, a shift amount detection process is performed (S17). In the displacement amount detection process (S17), the positions of the plurality of feature points of the work W detected by the process of S16 and the positions of the weld line L of the work W taught by the user, indicated by the teaching data 33b. The amount of deviation is detected for each feature point. Then, the deviation amount for each of the detected feature points is stored in the RAM 33 as deviation amount data 33 f.

  Next, based on the amount of displacement (the amount of displacement stored in the displacement amount data 33f) calculated by the process of S17, there is a displacement between the laser beam C irradiated to the workpiece W and the welding line L of the actual workpiece W It is determined whether there is any (S18). In the process of S17, the positions of the plurality of feature points of the workpiece W detected by the process of S16 indicate the positions of the weld line L in the actual workpiece W, and the weld line of the workpiece W taught by the user The position of L shows the irradiation position of the laser beam C irradiated to the workpiece W. Therefore, it can be determined whether there is a deviation between the laser beam C irradiated to the workpiece W and the welding line L of the actual workpiece W from the displacement amount calculated by the process of S17.

  Here, as described above, in the laser welding apparatus T, when the seam tracking controller 30 does not determine that there is a difference between the laser beam C irradiated to the workpiece W and the welding line L of the actual workpiece W, the workpiece The irradiation position of the laser beam C irradiated to W is controlled to move within a predetermined range from the weld line L of the workpiece W. That is, it is not permitted to determine that the movement within the predetermined range is due to the deviation between the laser beam C irradiated to the workpiece W and the welding line L of the actual workpiece W. Therefore, in the process of S18, when it is determined that the irradiation position of the laser beam C with which the workpiece W is irradiated exceeds the predetermined range from the welding line L of the workpiece W from the displacement amount calculated in the process of S17. It is determined that there is a deviation between the laser beam C irradiated to the workpiece W and the welding line L of the actual workpiece W.

  As a result of the determination in S18, when it is determined that there is a deviation (S18: Yes), next, position correction amount calculation processing is executed (S19). In the position correction amount calculation process (S19), the correction amount of the position correction to be applied to the position of the weld line L of the workpiece W taught by the user, which is indicated by the teaching data 33b, is calculated as follows. That is, based on a plurality of deviations indicated by deviation amount data 33f, the position of already welded welding line L indicated by current welding line data 33c and the point indicated by the current spot point data 33d The position of the welding line L of the taught work W is set so that the irradiation position of the laser light C moves from the irradiation position of the laser light C to the position of the feature point of the work W indicated by the characteristic point data 33e. The position correction amount for correction is calculated. The calculated position correction amount is stored in the RAM 33 as position correction amount data 33g.

  Then, the position correction amount calculated in the process of S19 is included in the movement command of the irradiation position of the laser light C, and is transmitted to the galvano scanner controller 18 of the galvano scanner G (S20). Thereby, the galvano scanner controller 18 drives the X-axis displacement motor 20a and the Y-axis displacement motor 20b based on the position correction amount included in the movement command, and the position of the feature point of the detected workpiece W (actual workpiece The irradiation position of the laser light C is corrected so that the laser light C is irradiated to the welding line L) of W.

  If it is not determined that there is a deviation as a result of the determination in S18 (S18: No), it is then determined whether the moving point flag 33i is on (S21). As a result of the determination in S21, if the moving point flag 33i is on (S21: Yes), the moving amount is based on the moving point A data 32a so as to move the irradiation position of the laser light C toward the point A. The movement amount calculated and calculated is included in the movement command of the irradiation position of the laser light C and transmitted to the galvano scanner controller 18 (S22). Thereby, the galvano scanner controller 18 drives the X-axis displacement motor 20a and the Y-axis displacement motor 20b based on the movement amount included in the movement command, and the irradiation position of the laser light C is moved toward the point A. . After the process of S22, the movement point flag 33i is set to OFF (S23).

  On the other hand, if it is determined that the moving point flag 33i is not on but off as a result of the determination in S21 (S21: No), the moving amount is moved so as to move the irradiation position of the laser light C toward the point B The movement amount calculated based on the point B data 32b is included in the movement command of the irradiation position of the laser light C and transmitted to the galvano scanner controller 18 (S24). Thus, the galvano scanner controller 18 drives the X-axis displacement motor 20a and the Y-axis displacement motor 20b based on the movement amount included in the movement command, and the irradiation position of the laser light C is moved toward the point B. . After the process of S24, the movement point flag 33i is set to ON (S25).

  By the processing of S23 and S25, the movement point flag 33i is set to "off" when movement control toward the point A is performed because it is "on", and it is "off". Since the movement control toward the point B is set to "on", it is not determined that there is a difference between the laser beam C irradiated to the workpiece W and the welding line L of the actual workpiece W. The movement of the laser light C applied to the workpiece W, which is performed by the galvano scanner G, can be transferred between the point A and the point B.

  When the process of S20, S23 or S25 is executed, it is then determined whether the welding of the workpiece W is completed (S26). Specifically, it is determined that the welding of the workpiece W is completed when the welding is completed up to the end of the taught welding line L and when the end of welding is instructed by the user. As a result of the determination in S26, if the welding of the workpiece W is not completed (S26: No), the process returns to S11. On the other hand, as a result of the determination in S26, when the welding of the workpiece W is completed (S26: Yes), the laser position moving process is completed.

  As described above, according to the laser welding apparatus T in this embodiment, the multi-axis robot R uses the galvano scanner G as the work W along the welding line L of the work W taught in advance by the control of the robot controller 40. Move against. The laser beam C is irradiated from the galvano scanner G along the weld line L of the workpiece W, and the workpiece W is welded at the weld line L. The galvano scanner G is configured such that the irradiation position of the laser light C on the workpiece W can be moved also by the galvano mirror unit 20 provided in the galvano scanner G. The movement of the irradiation position of the laser light C by the galvano mirror unit 20 is controlled by the seam tracking controller 30.

  Here, the seam tracking controller 30 determines whether there is a deviation between the irradiation position of the laser beam C irradiated to the workpiece W and the welding line L of the actual workpiece W by the processing of S18 of the laser position movement processing. Be done. If it is determined by S18 that there is a deviation, the galvano mirror unit 20 of the galvano scanner G is controlled such that the irradiation position of the laser light C moves to the welding line L of the actual workpiece W. On the other hand, if it is not determined that there is a shift according to the determination in S18, the galvano mirror unit 20 of the galvano scanner G controls so that the irradiation position of the laser light C moves within a predetermined range from the welding line L of the work W Be done.

  Thereby, when a shift occurs between the irradiation position of the laser light C and the welding line L while always irradiating the laser light C within a predetermined range from the welding line L, the irradiation of the laser light C is not stopped. The irradiation position of the laser beam C can be returned to the welding line L. Therefore, good quality laser welding can be performed.

  As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited at all to the said embodiment, It is easy that various improvement deformation | transformation is possible within the range which does not deviate from the meaning of this invention. It can be guessed. For example, although the internal configuration of the galvano scanner G and the seam tracking head S is shown in FIG. 2, the arrangement of the lenses and mirrors may be appropriately changed by the galvano scanner G and the seam tracking head S. Further, FIG. 3 shows the electrical configuration of the seam tracking controller 30 according to an embodiment of the present invention. However, if the processing shown in FIG. 6 can be realized, the electrical configuration is shown in FIG. It is not limited at all.

  Moreover, although the said embodiment demonstrated the laser welding apparatus T which displaces the irradiation position of the laser beam C irradiated to the workpiece W using the galvano mirror part 20 of XY axis, XY-Z 3-axis The present invention may be applied to a laser welding apparatus in which the irradiation position of the laser beam irradiated to the workpiece W is displaced using the galvano scanner of the above.

In this case, the seam tracking controller 30 moves the irradiation position of the laser beam C when it is not determined that there is a deviation between the laser beam C irradiated to the workpiece W and the weld line L in the actual workpiece W, The z-axis direction, which is a direction perpendicular to the surface (welding surface) of the workpiece W where the welding line L is set, may be made to pass. When the laser beam C is transported in the z-axis direction, it may be set so as to be within a predetermined range from the welding line L (the range from the welding line L to z _L or less). Here, when the laser light C is irradiated in the range where the focal position of the laser light C is taken into consideration, the laser light C substantially falls within the range of the distance z _L or less from the welding line L. It is a range that can be substantially identified with the one focused and illuminated. Thereby, even if movement of the laser beam C in the z-axis direction is performed by the galvano scanner G, good quality laser welding can be performed along the welding line L.

  In the above embodiment, the seam tracking controller 30 does not determine that there is a difference between the laser beam C irradiated to the workpiece W and the welding line L of the actual workpiece W, as shown in FIG. Although the case where the irradiation position of the laser light C is moved by the axial traffic or the y-axial traffic shown in FIG. 5A has been described, the x-axial traffic, the y-axial traffic, and The irradiation position of the laser beam C may be moved by combining at least two axial traveling in the z axial traveling. For example, the irradiation position of the laser light C may be moved by combining traveling in the x-axis direction shown in FIG. 4A or traveling in the y-axis direction shown in FIG. 5A.

C Laser light G Galvano scanner (part of laser irradiation device)
L welding line R multi-axis robot (moving device)
S Seam tracking head (part of laser irradiation device)
T Laser welding equipment W Work (workpiece)
20 Galvano mirror (moving means)
21 fθ lens 21 (irradiation means)
30 Seam Tracking Controller (Laser Irradiator Control Means)
33b Teaching data (acquisition means)
40 Robot Controller (Moving Device Control Means)
S18 (determination means)
S20 (first movement control means)
S22, S24 (second movement control means)

Claims (5)

The laser irradiation device for irradiating a laser beam to a welding object, and a moving device capable of moving the laser irradiation device with respect to the welding object, the laser irradiation device being the welding object by the moving device A laser welding device for welding the welding object with laser light emitted from the laser irradiation device to the welding object while being moved with respect to
The moving device is
A moving device control unit configured to control the laser irradiation device to move along a preset welding line of the object to be welded;
The laser irradiation device is
An irradiation unit that condenses laser light and irradiates the object to be welded;
Moving means for moving the irradiation position of the laser light emitted from the irradiation means on the object to be welded;
Laser irradiation device control means for controlling the movement of the irradiation position by the movement means;
The laser irradiation device control means is
Determining means for determining whether there is a deviation between the irradiation position of the laser beam irradiated to the object to be welded and the welding line;
First movement control means for controlling the moving means to move the irradiation position to the welding line when it is judged by the judging means that there is the deviation;
And second movement control means for controlling the movement means such that the irradiation position moves within a predetermined range from the welding line when it is not judged by the judgment means that the deviation is present. Laser welding equipment.   The laser welding apparatus according to claim 1, wherein the second movement control means controls the movement means so that the irradiation position moves at least on the welding line.   The second movement control means is characterized in that, when the movement of the irradiation position is performed a plurality of times, the movement is controlled such that the cumulative movement distance by the second movement control means becomes zero. The laser welding apparatus according to claim 1 or 2.   The moving speed of the irradiation position of the laser light in the direction parallel to the welding line by the control of the second movement control means is the moving speed of the irradiation position of the laser light by the moving device. The laser welding apparatus according to any one of claims 1 to 3, wherein the irradiation position of the laser beam is moved so as to be smaller. The laser irradiation apparatus control means includes an acquisition means for acquiring, from the movement device, information on the position of a weld line preset for the movement device.
The second movement control means controls the movement means so that the irradiation position moves within a predetermined range from the welding line based on the information on the position of the welding line acquired by the acquiring means. The laser welding apparatus according to any one of claims 1 to 4, characterized in that:

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