JP2007167896A - Seam welding machine, seam welding apparatus, seam welding robot system, seam welding method, and method of creating rotary driving control program for roller electrode - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To mitigate a load applied on a worker in a manual work and to prevent a work from being deformed by enabling a seam welding apparatus (or a work) to be rotated without requiring large power. <P>SOLUTION: The seam welding machine 3 comprises: two roller electrodes 25, 27 performing seam welding to the object to be welded; a power source 5 performing energization to the two roller electrodes 25, 27; a pressurization means 24 for pressurizing the roller electrode 25 toward the roller electrode 27; first rotary driving means 26, 29 rotating the respective roller electrodes 25, 27 around an axis passing through the center of the roller electrodes 25, 27 and further almost orthogonal to the radial direction of the roller electrodes 25, 27; and a second rotary driving means 30 rotating the roller electrode 27 around an axis almost orthogonal to the tangential direction of the roller 27 passing through the contact between the object to be welded and the roller electrode 27, and to the rotary axis direction of the roller electrodes 25, 27 by the first rotary driving means 26, 29. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a seam welding machine, a seam welding apparatus, a seam welding robot system, a seam welding method, and a roller electrode rotation drive control program creation method.

Conventionally, seam welding for joining two metal plates by energizing the roller electrode and rotating the roller electrode while sandwiching and pressing the two metal plates by two roller electrodes is known. (For example, refer to Patent Document 1).
JP 7-290249 A

By the way, when welding in a curved shape like a metal fuel tank, it is necessary to advance the roller electrode while drawing a curve in a state where a work (metal plate) is sandwiched between two roller electrodes. In this case, when the pressure applied to the work is large, the frictional force between the work and the two roller electrodes caused by pressurization causes the seam welding apparatus (or work) including the two roller electrodes to rotate. Requires a lot of power.
For this reason, if this is done manually, it will be a heavy labor, and if it is performed by a machine such as a robot, a large machine with a large output will be required. growing.
Moreover, since the jig | tool which fixes a workpiece | work should be strengthened or many jigs must be provided, cost increases. Furthermore, there exists a possibility that a workpiece | work may deform | transform by rotating a seam welding apparatus (or workpiece | work) with a big force.

  Therefore, the present invention has been made to solve the above-described problems, and can rotate the seam welding apparatus (or the workpiece) without requiring a large force, and the burden on the operator when performing manually. It is an object of the present invention to provide a seam welding machine, a seam welding apparatus, a seam welding robot system, a seam welding method, and a roller electrode rotation drive control program creation method capable of realizing reduction and prevention of workpiece deformation.

  According to the first aspect of the present invention, in the seam welding machine, two rollers are formed in a circular shape and perform seam welding on the workpiece by energizing the workpiece while being in contact with each other. An electrode, a power source for energizing the two roller electrodes, a pressing means for pressing one of the two roller electrodes toward the other roller electrode, and each roller electrode. A first rotation driving means for rotating the roller electrode about an axis that passes through the center of the roller electrode and is substantially orthogonal to the radial direction of the roller electrode; and one roller electrode, the workpiece and the one roller electrode, And a second rotation driving means for rotating about the axis substantially perpendicular to the tangential direction of the one roller electrode passing through the contact point and the rotation axis direction of the roller electrode by the first rotation driving means. The features.

  According to a second aspect of the present invention, in the seam welding apparatus, two rollers are formed in a circular shape and perform seam welding on the work piece by energizing the work pieces in contact with each other. An electrode, a power source for energizing the two roller electrodes, a pressing means for pressing one of the two roller electrodes toward the other roller electrode, and each roller electrode. A first rotation driving means for rotating the roller electrode about an axis that passes through the center of the roller electrode and is substantially orthogonal to the radial direction of the roller electrode; and one roller electrode, the workpiece and the one roller electrode, A second rotation drive means for rotating about the axis substantially perpendicular to the tangential direction of the one roller electrode passing through the contact and the rotation axis direction of the roller electrode by the first rotation drive means; Calculated by a rotation angle calculation means for calculating a rotation angle of the one roller electrode rotated by the second rotation drive means based on a curvature of a welding curve to be welded in a curved shape in the object, and the rotation angle calculation means Drive control means for performing drive control of the second rotation drive means so as to rotate the one roller electrode by the set rotation angle.

  According to a third aspect of the present invention, in the seam welding apparatus according to the second aspect of the invention, the rotation angle calculation means is the second rotation driving means based on the curvature of the welding curve and the welding speed of the workpiece. The rotation angle of the one roller electrode to be rotated is calculated.

  According to a fourth aspect of the present invention, in the seam welding robot system, a robot having an arm having a plurality of joints and a driving means for driving the arm, and provided at the tip of the arm, is formed in a circular shape. Two roller electrodes for performing seam welding on the workpiece, a power source for energizing the two roller electrodes, and the two rollers. Among the electrodes, pressure means for pressing one roller electrode toward the other roller electrode and each roller electrode are provided, and each roller electrode passes through the center of the roller electrode and in the radial direction of the roller electrode. The first rotation driving means for rotating around a substantially orthogonal axis and the one roller electrode are connected to the one roller electrode passing through the contact point between the workpiece and the one roller electrode. And a second rotation driving means for rotating about the axis substantially orthogonal to the rotation axis direction of the roller electrode by the first rotation driving means, and a welding curve in which welding is performed in a curved shape on the workpiece. A rotation angle calculation unit that calculates a rotation angle of the one roller electrode that is rotated by the second rotation driving unit based on the curvature of the first rotation electrode, and the one roller electrode is moved by the rotation angle calculated by the rotation angle calculation unit. Drive control means for performing drive control of the second rotation drive means so as to rotate.

  According to a fifth aspect of the present invention, in the seam welding robot system, an arm having a plurality of joints, a gripping unit that is provided at a tip of the arm and grips the workpiece, and a driving unit that drives the arm; And two rollers that are fixed to the floor, are formed in a circular shape, and are energized in a state where they are in contact with the workpiece, thereby performing seam welding on the workpiece. An electrode, a power source for energizing the two roller electrodes, a pressing means for pressing one of the two roller electrodes toward the other roller electrode, and each roller electrode. A first rotation driving means for rotating the roller electrode about an axis passing through the center of the roller electrode and substantially perpendicular to the radial direction of the roller electrode; Second rotation driving means for rotating about a tangential direction of the one roller electrode passing through a contact point between the object and one of the roller electrodes and an axis substantially orthogonal to the rotation axis direction of the roller electrode by the first rotation driving means. A rotation angle calculating means for calculating a rotation angle of the one roller electrode rotated by the second rotation driving means based on a curvature of a welding curve to be welded in a curved shape in the workpiece, and the rotation Drive control means for performing drive control of the second rotation drive means so as to rotate the one roller electrode by the rotation angle calculated by the angle calculation means.

  According to a sixth aspect of the present invention, in the seam welding method using the seam welding apparatus according to the second aspect, the energization step of energizing the two roller electrodes by the power source and the one of the one by the pressurizing means. Each of the roller electrodes passes through the center of the roller electrode and is substantially orthogonal to the radial direction of the roller electrode by the pressurizing step of pressing the roller electrode toward the other roller electrode and the first rotation driving means. The first rotation driving step of rotating around the axis and the rotation angle calculating means rotate the second rotation driving means based on the curvature of a welding curve to be welded in a curved shape on the workpiece. A rotation angle calculating step of calculating a rotation angle of one roller electrode; and the one of the roller electric powers by the rotation angle calculated by the rotation angle calculating means by the drive control means. Is rotated around an axis substantially perpendicular to the tangential direction of the one roller electrode passing through the contact point between the workpiece and the one roller electrode and the rotation axis direction of the roller electrode by the first rotation driving means. And a drive control step for performing drive control of the second rotation drive means.

  According to a seventh aspect of the present invention, in the seam welding method using the seam welding robot system according to the fourth aspect, the arm is driven by the driving means to a position where the two roller electrodes sandwich the workpiece. A driving step for energizing the two roller electrodes by the power source, a pressing step for pressing one roller electrode toward the other roller electrode by the pressurizing unit, and the first step A first rotation driving step of rotating each roller electrode about an axis that passes through the center of the roller electrode and is substantially perpendicular to the radial direction of the roller electrode by the rotation driving unit; and The rotation angle of the one roller electrode rotated by the second rotation driving means is calculated based on the curvature of the welding curve that is welded in a curved shape in the weldment. A rotation angle calculating step, and the one roller electrode passing through the contact point between the work piece and the one roller electrode by the rotation angle calculated by the rotation angle calculating means by the drive control means. A drive control step of performing drive control of the second rotation drive unit so as to rotate about an axis substantially orthogonal to the tangential direction of the electrode and the rotation axis direction of the roller electrode by the first rotation drive unit. It is characterized by that.

  According to an eighth aspect of the present invention, in the seam welding method using the seam welding robot system according to the fifth aspect, the gripping unit grips the workpiece by the gripping unit, and the gripping unit includes the driving unit. A driving step of driving the arm to a position where the two roller electrodes are sandwiched between the workpieces, an energizing step of energizing the two roller electrodes by the power source, A pressurizing step of pressurizing one roller electrode toward the other roller electrode by the pressurizing means, and each roller electrode passes through the center of the roller electrode by the first rotational driving means and The workpiece is welded in a curved shape by the first rotation driving step of rotating around an axis substantially orthogonal to the radial direction and the rotation angle calculation means. A rotation angle calculating step of calculating a rotation angle of the one roller electrode rotated by the second rotation drive unit based on a curvature of a tangent curve; and a rotation calculated by the rotation angle calculation unit by the drive control unit. The one roller electrode is substantially perpendicular to the tangential direction of the one roller electrode passing through the contact point between the workpiece and the one roller electrode and the rotation axis direction of the roller electrode by the first rotation driving means by an angle. A drive control step of performing drive control of the second rotation drive means so as to rotate around the axis.

  According to a ninth aspect of the present invention, in the seam welding robot system according to the fourth or fifth aspect, in the rotation drive control program creating method for the roller electrode, a teaching operation for the robot is performed based on a teaching program for operating the robot. A teaching step for recording, a recording step for recording robot teaching operation information in the teaching step, and welding in which the workpiece is welded in a curved shape based on the robot teaching operation information recorded in the recording step A curvature calculating step for calculating a curvature of a curve, and a rotation angle calculating step for calculating a rotation angle of the one roller electrode rotated by the second rotation driving unit based on the curvature calculated by the curvature calculating step. And rotating the one roller electrode by the rotation angle calculated by the rotation angle calculation step. Characterized in that it comprises a program generation step of generating a drive control program of the second rotary drive means.

According to the first aspect of the present invention, when seam welding is performed, the two roller electrodes are brought into contact with the workpiece and the two roller electrodes are energized by the power source. The pressing means pressurizes one roller electrode toward the other roller electrode. Then, seam welding is performed by rotating the two roller electrodes about the axis that passes through the center of the roller electrode and is substantially orthogonal to the radial direction of the roller electrode by the first rotation driving means.
Here, since the seam welder is provided with the second rotation driving means, one roller electrode is connected to the tangential direction of the one roller electrode passing through the contact point between the workpiece and the one roller electrode and the first roller electrode. The rotation drive means can rotate the roller electrode about an axis substantially orthogonal to the rotation axis direction of the roller electrode.

That is, when welding is performed in a curved shape on the workpiece, a larger frictional force acts on the roller electrode than when welding in a linear shape. In such a case, the second rotation driving means is driven to cause one roller electrode to pass through the contact point between the work piece and one roller electrode, and the tangential direction of the one roller electrode and the first rotation driving means. By rotating the roller electrode about the axis substantially perpendicular to the rotation axis direction of the roller electrode, the resultant force of the force to move in the tangential direction passing through the contact point with the workpiece in each roller electrode is It acts in a direction different from the tangential direction passing through the contact point with the object. Therefore, the second rotational drive means rotates one of the roller electrodes so that the tangential direction of the one roller electrode is along the tangential direction of the curve. It becomes possible to act.
Therefore, compared with the case where one of the roller electrodes is not rotated, the two roller electrodes can be rotated without requiring a large force, and the roller electrodes can be rotated. It is possible to reduce the burden and prevent deformation of the workpiece.

According to the second and sixth aspects of the invention, when performing seam welding, the two roller electrodes are brought into contact with the workpiece and the two roller electrodes are energized by the power source (energization process). The pressurizing means pressurizes one roller electrode toward the other roller electrode (pressurizing step). Then, seam welding is performed by rotating the two roller electrodes about an axis that passes through the center of the roller electrode and is substantially orthogonal to the radial direction of the roller electrode by the first rotation driving means (first Rotation drive process).
Here, the rotation angle calculation means calculates the rotation angle of one of the roller electrodes rotated by the second rotation drive means based on the curvature of the welding curve that is welded in a curved shape on the workpiece (rotation angle calculation). Process). Then, the drive control means performs drive control of the second rotation drive means so as to rotate one roller electrode by the rotation angle calculated by the rotation angle calculation means (drive control process). Thus, the second rotation driving means rotates one of the roller electrodes (second rotation driving process).
Thus, the second rotation driving means is substantially orthogonal to the tangential direction of the one roller electrode passing through the contact point between the work piece and the one roller electrode and the rotation axis direction of the roller electrode by the first rotation driving means. One roller electrode can be rotated based on the angle calculated about the axis.

That is, when welding is performed in a curved shape on the workpiece, a larger frictional force acts on the roller electrode than in the case of welding in a linear shape. In such a case, the second rotation driving means is driven to cause one roller electrode to pass through the contact point between the work piece and one roller electrode, and the tangential direction of the one roller electrode and the first rotation driving means. By rotating the roller electrode about the axis substantially perpendicular to the rotation axis direction of the roller electrode, the resultant force of the force to move in the tangential direction passing through the contact point with the workpiece in each roller electrode is It acts in a direction different from the tangential direction passing through the contact point with the object. Therefore, by rotating the one roller electrode by the calculated rotation angle by the second rotation driving means, a force along the weld line can be applied to the workpiece.
Therefore, compared with the case where one of the roller electrodes is not rotated, the two roller electrodes can be rotated without requiring a large force, and the roller electrodes can be rotated. It is possible to reduce the burden and prevent deformation of the workpiece.

  According to the third aspect of the invention, since the rotation angle of one of the roller electrodes is calculated in consideration of not only the curvature of the welding curve but also the welding speed, the accuracy of the rotation angle calculation can be improved.

According to the fourth and seventh aspects of the invention, when performing seam welding, the arm is driven by driving the drive means so that the two roller electrodes sandwich the workpiece (drive process), and the robot Two roller electrodes provided at the front end are brought into contact with the workpiece, and the two roller electrodes are energized by a power source (energization process).
The pressurizing means pressurizes one roller electrode toward the other roller electrode (pressurizing step). Then, seam welding is performed by rotating the two roller electrodes about an axis that passes through the center of the roller electrode and is substantially orthogonal to the radial direction of the roller electrode by the first rotation driving means (first Rotation drive process).
Here, the rotation angle calculation means calculates the rotation angle of one of the roller electrodes rotated by the second rotation drive means based on the curvature of the welding curve that is welded in a curved shape on the workpiece (rotation angle calculation). Process). Then, the drive control means performs drive control of the second rotation drive means so as to rotate one roller electrode by the rotation angle calculated by the rotation angle calculation means (drive control process). Thus, the second rotation driving means rotates one of the roller electrodes (second rotation driving process).
As a result, the second rotation driving means is arranged around an axis substantially orthogonal to the tangential direction of the one roller electrode passing through the contact point between the work piece and one roller electrode and the rotation axis direction of the roller electrode by the rotation driving means. One roller electrode can be rotated based on the calculated angle.

That is, when welding is performed in a curved shape on the workpiece, a larger frictional force acts on the roller electrode than in the case of welding in a linear shape. In such a case, the second rotation driving means is driven to cause one roller electrode to pass through the contact point between the work piece and one roller electrode, and the tangential direction of the one roller electrode and the first rotation driving means. By rotating the roller electrode about the axis substantially perpendicular to the rotation axis direction of the roller electrode, the resultant force of the force to move in the tangential direction passing through the contact point with the workpiece in each roller electrode is It acts in a direction different from the tangential direction passing through the contact point with the object. Therefore, by rotating the one roller electrode by the calculated rotation angle by the second rotation driving means, a force along the weld line can be applied to the workpiece.
Therefore, compared with the case where one of the roller electrodes is not rotated, the two roller electrodes can be rotated without requiring a large force, and the roller electrodes can be rotated. It is possible to reduce the burden and prevent deformation of the workpiece.

According to the fifth and eighth aspects of the invention, when seam welding is performed, the workpiece is gripped by the gripping means provided at the tip of the robot (gripping step), and the workpiece is against the floor. The drive means is driven so as to be sandwiched between the two fixed roller electrodes to drive the arm (drive process). Then, the work piece is brought into contact with the two roller electrodes, and the two roller electrodes are energized by the power source. Thus, the second rotation driving unit rotates one of the roller electrodes (energization process).
Further, the pressurizing unit pressurizes one roller electrode toward the other roller electrode, and thus the second rotation driving unit rotates the one roller electrode (pressurizing step). Then, seam welding is performed by rotating the two roller electrodes about an axis that passes through the center of the roller electrode and is substantially orthogonal to the radial direction of the roller electrode by the first rotation driving means (first Rotation drive process).
Here, the rotation angle calculation means calculates the rotation angle of one of the roller electrodes rotated by the second rotation drive means based on the curvature of the welding curve that is welded in a curved shape on the workpiece (rotation angle calculation). Process). Then, the drive control means performs drive control of the second rotation drive means so as to rotate one roller electrode by the rotation angle calculated by the rotation angle calculation means (drive control process). Thus, the second rotation driving means rotates one of the roller electrodes (second rotation driving process).
Thus, the second rotation driving means is substantially orthogonal to the tangential direction of the one roller electrode passing through the contact point between the work piece and the one roller electrode and the rotation axis direction of the roller electrode by the first rotation driving means. One roller electrode can be rotated based on the angle calculated about the axis.

That is, when welding is performed in a curved shape on the workpiece, a larger frictional force acts on the roller electrode than when welding in a linear shape. In such a case, the second rotation driving means is driven to cause one roller electrode to pass through the contact point between the work piece and one roller electrode, and the tangential direction of the one roller electrode and the first rotation driving means. By rotating the roller electrode about the axis substantially perpendicular to the rotation axis direction of the roller electrode, the resultant force of the force to move in the tangential direction passing through the contact point with the workpiece in each roller electrode is It acts in a direction different from the tangential direction passing through the contact point with the object. Therefore, by rotating the one roller electrode by the calculated rotation angle by the second rotation driving means, a force along the weld line can be applied to the workpiece.
Therefore, compared with the case where one of the roller electrodes is not rotated, the two roller electrodes can be rotated without requiring a large force, and the roller electrodes can be rotated. It is possible to reduce the burden and prevent deformation of the workpiece.

According to the ninth aspect of the invention, in the teaching step, the robot is caused to perform a teaching operation based on a teaching program for operating the robot. Next, in the recording step, teaching operation information of the robot in the teaching step is recorded. Next, in the curvature calculation step, the curvature of the welding curve that is welded in a curved shape on the workpiece is calculated based on the teaching operation information of the robot recorded in the recording step. Next, in the rotation angle calculation step, the rotation angle of one roller electrode rotated by the second rotation driving unit is calculated based on the curvature calculated in the curvature calculation step. Next, in the program creation step, a drive control program for the second rotation drive means is created so that one of the roller electrodes is rotated by the rotation angle calculated in the rotation angle calculation step.
As a result, the roller electrode drive control by the second rotation driving means can be performed only by performing the teaching operation of the robot, thereby facilitating the creation of the teaching program, reducing the work time, and reducing the work cost. And production preparation lead time can be shortened. In addition, since the program is created using information when the robot is operated, a program with high synchronization accuracy with the robot can be created.

Hereinafter, the best mode of a seam welding machine, a seam welding apparatus, a seam welding robot system, a seam welding method, and a roller electrode rotation drive control program creation method will be described in detail with reference to the drawings.
<Configuration of seam welding machine, seam welding equipment, seam welding robot system>
The configurations of the seam welding machine, the seam welding apparatus, and the seam welding robot system will be described.
As shown in FIG. 1, the seam welding robot system 10 is used when a workpiece W is produced by joining a main body W1 and a lid W2, for example, when producing a metal fuel tank.
The seam welding robot system 10 includes a robot 1 that operates within a predetermined operation range when a driving force is applied, and a seam welding device 2 provided in the robot 1.

(robot)
The robot 1 includes a base 12 serving as a base, a plurality of arms 14 connected by joints 13, servo motors 15 (see FIG. 2) as driving means provided at the joints 13, and shafts of the servo motors 15. And an encoder (not shown) for detecting each angle. And the seam welding apparatus 2 which performs seam welding to the workpiece | work W as a to-be-welded object (for example, metal plate) is equipped in the front-end | tip part of the arm 14 arrange | positioned most at the front-end | tip.
Each joint 13 is either a swing joint that pivots one end of the arm 14 and pivotally supports the other end, or a rotary joint that pivotally supports the arm 14 so that the arm 14 itself can rotate about its longitudinal direction. Composed. That is, the robot 1 corresponds to a so-called articulated robot.

(Seam welding equipment)
The seam welding device 2 includes a seam welder 3 and a control device 4 that controls the operation of the seam welder.
The seam welder 3 includes a support base 21 provided at the distal end portion of the arm 14 disposed at the most distal end of the robot 1. The support base 21 is a substantially rectangular plate material that is long in the vertical direction. The support base 21 is provided with a guide rail 22 extending in the vertical direction from the vicinity of the upper end to the vicinity of the center. The guide rail 22 is provided with a movable base 23 that is fitted into the guide rail 22 and is slidable along the guide rail 22. The movable base 23 is connected to the tip of a piston rod 24 a of an air cylinder 24 that serves as a drive source when the movable base 23 is slid along the guide rail 22.

  The air cylinder 24 is provided at the upper end portion of the support base 21, and is provided on the support base 21 so that the piston rod 24a expands and contracts along the vertical direction. By extending the piston rod 24a, the movable base 23 connected to the piston rod 24a slides downward on the guide rail 22, and by contracting the piston rod 24a, the movable base 23 connected to the piston rod 24a. Slides on the guide rail 22 upward. That is, the air cylinder 24 functions as a pressurizing unit that pressurizes the roller electrode 25 toward the roller electrode 27 out of the two roller electrodes 25 and 27. The air cylinder 24 is connected to the control device 4, and the drive of the piston rod 24 a is controlled by a drive control signal transmitted from the control device 4.

  The movable base 23 is provided with a roller electrode 25 that performs seam welding on the work W by energizing the work W while being in contact with the work W. The roller electrode 25 is formed in a substantially perfect circular disk shape and has a rotation shaft at the center thereof. Connected to the roller electrode 25 is an electrode rotation motor 26 as a first rotation driving means for rotating the roller electrode 25 around an axis substantially perpendicular to the radial direction of the roller electrode 25 while passing through the center of the roller electrode 25. ing. The electrode rotation motor 26 is provided on the back side of the movable table 23 and is supported by the movable table 23. Here, the roller electrode 25 is provided such that its rotation axis is along a direction (substantially horizontal direction) orthogonal to the moving direction (vertical direction) of the movable base 23.

A roller electrode 27 that performs seam welding on the work W by energizing the work W while being in contact with the work W is provided below the support base 21 via a fixed base 28. The roller electrode 27 is disposed on the same plane as the disk portion of the roller electrode 25. When the roller electrode 25 is lowered, the workpiece W is sandwiched between the roller electrode 25 and the roller electrode 27 and seam welding is performed. Be able to. The fixed base 28 is fixed to the support base 21, and the roller electrode 27 cannot move like the roller electrode 25. Connected to the roller electrode 27 is an electrode rotation motor 29 as a first rotation driving means for rotating the roller electrode 27 around an axis substantially perpendicular to the radial direction of the roller electrode 27 while passing through the center of the roller electrode 27. ing. The electrode rotation motor 29 is provided on the back side of the fixed base 28 and is supported by the fixed base 28.
Further, on the lower surface of the fixed base 28, the roller electrode 27 is substantially orthogonal to the tangential direction of the roller electrode 27 passing through the contact point between the workpiece W and the roller electrode 27 and the rotation axis direction of the roller electrode 27 by the electrode rotation motor 29. A fixed table rotation motor 30 is provided as second rotation driving means for rotating around the axis. Specifically, the fixed table rotation motor 30 can rotate the roller electrode 27 provided on the fixed table 28 around the Z axis by rotating the fixed table 28 around the Z axis in FIG.

  Here, the roller electrode 27 is provided such that its rotation axis is along a direction (substantially horizontal direction) orthogonal to the moving direction (vertical direction) of the movable table 23. The electrode rotation motors 26 and 29 are controlled so as to rotate in opposite directions when viewed from the same direction. Specifically, for example, the roller electrode 25 rotates clockwise toward the paper surface in FIG. 1, and the roller electrode 27 rotates counterclockwise toward the paper surface in FIG.

  As a result, the two roller electrodes 25 and 27 have rotation axes that are parallel to each other, the tangent line passing through the lowermost peripheral edge of the roller electrode 25 positioned above and the uppermost end of the roller electrode 27 positioned below. Both tangents passing through the peripheral edge extend in a direction (X direction in FIG. 1) perpendicular to the moving direction (Z direction in FIG. 1) and the rotation axis direction (Y direction in FIG. 1) of the movable base 23. It has become. That is, these tangential directions become the traveling direction (X direction in FIG. 1) of the robot 1 (roller electrodes 25 and 27).

The two roller electrodes 25 and 27 are both connected to a welding power source 5 as a power source for supplying a current necessary for welding. The welding power source 5 is connected to a control device 4 that controls the operation of the seam welding device 2. That is, a welding timing signal is transmitted to the welding power source 5 by the control device 4, and the welding power source 5 energizes the roller electrodes 25 and 27 based on the received timing signal. The energized roller electrodes 25 and 27 are subjected to seam welding when they are in contact with the circular outer periphery and the workpiece W.
Moreover, the workpiece | work W in which seam welding is performed is a metal fuel tank etc., for example, is mounted on the mounting base S for performing welding, and the main-body part W1 and the cover part W2 are by the seam welding apparatus 2. Welded.

(Control device)
FIG. 2 is a block diagram illustrating a configuration of the seam welding robot system 10.
The control device 4 includes a CPU 41 that executes each process in accordance with a process program related to the drive control of the robot 1 and the operation control of the seam welding apparatus 2, and a memory 42 that stores a process program, process data, and the like for executing each process. It is equipped with.
The memory 42 has a program area 43 in which a program necessary for performing drive control of the robot 1 and operation control of the seam welding apparatus 2 is stored, and is necessary for performing drive control of the robot 1 and operation control of the seam welding apparatus 2. A data area 44 in which various data are stored, and a work area 45 in which various work memories and counters are provided and each process is performed are formed.

The program area 43 stores a teaching program 43a that realizes a function of causing the robot 1 to perform a teaching operation. That is, when the CPU 41 executes the teaching program 43a, the control device 4 functions as teaching means.
In the program area 43, a rotation angle calculation program that realizes a function of calculating the rotation angle of one roller electrode 27 that the fixed base rotation motor 30 rotates based on the curvature of a welding curve that is welded in a curved shape on the workpiece W. 43b is stored. That is, when the CPU 41 executes the rotation angle calculation program 43b, the control device 4 functions as a rotation angle calculation unit.
The program area 43 stores a drive control program 43c that realizes a function of performing drive control of the fixed base rotation motor 30 so as to rotate one roller electrode 27 by the rotation angle calculated by the rotation angle calculation program 43b. Yes. That is, when the CPU 41 executes the drive control program 43c, the control device 4 functions as a drive control unit.
The program area 43 stores a program creation program 43d for creating a drive control program 43c for the fixed base rotation motor 30 so as to rotate one roller electrode 27 by the rotation angle calculated by the rotation angle calculation program 43b. . That is, when the CPU 41 executes the program creation program 43d, the control device 4 functions as a program creation unit.
The control device 4 is connected to the robot 1, the welding power source 5, and the air cylinder 24, all of which are operation-controlled by the control device 4.

FIG. 3 is a block diagram illustrating functions of a seam welding robot system 10 including the robot 1 and the seam welding apparatus 2.
The robot 1 has a drive unit 60 that drives the arm 14 to sandwich the workpiece W by the two roller electrodes 25 and 27, and the servo motor 15 takes on the function of the drive unit 60.
The seam welding apparatus 2 has two welded portions 61 and 62 that perform seam welding on the workpiece W by energization, and the roller electrodes 25 and 27 perform the functions of the welded portions 61 and 62.
The seam welding apparatus 2 includes a first rotation driving unit 63 that rotates the roller electrode 25 that is the welding unit 61 around the Y axis (see FIG. 1), and the function of the first rotation driving unit 63 is the electrode rotation. The motor 26 is responsible.
The seam welding apparatus 2 has a vertical movement unit 64 that moves the roller electrode 25 that is the welding unit 61 in the vertical direction (Z-axis direction in FIG. 1), and the movable table 23 takes on the function of the vertical movement unit 64.
The seam welding apparatus 2 includes a pressurizing unit 65 that pressurizes one roller electrode 25 that is the welded portion 61 toward the other roller electrode 27 that is the welded portion 62, and the function of the pressurizing unit 65 is an air cylinder. 24 bears.
The seam welding apparatus 2 includes a first rotation driving unit 66 that rotates the roller electrode 27 that is the welding unit 62 around the Y axis (see FIG. 1), and the function of the first rotation driving unit 66 is the electrode rotation. The motor 29 is responsible.
The seam welding apparatus 2 includes a second rotation driving unit 67 that rotates the roller electrode 27 that is the welding unit 62 around the Z axis (see FIG. 1), and the function of the second rotation driving unit 67 is fixed to the fixed base. The rotation motor 30 is responsible.
The seam welding apparatus 2 includes an energization unit 68 that energizes the two roller electrodes 25 and 27 that are the welding units 61 and 62, and the welding power source 5 takes on the function of the energization unit 68.

The seam welding apparatus 2 includes a teaching unit 69 that causes the robot 1 to perform a teaching operation when the CPU 41 executes the teaching program 43 a, and the teaching unit 69 functions as a teaching unit in the control device 4.
In the seam welding apparatus 2, when the CPU 41 executes the rotation angle calculation program 43 b, the fixed base rotation motor 30 rotates the fixed base rotation motor 30 based on the curvature of the welding curve that is welded in a curved shape on the workpiece W. A rotation angle calculation unit 70 that calculates a rotation angle is included, and the rotation angle calculation unit 70 functions as a rotation angle calculation unit in the control device 4.
In the seam welding apparatus 2, the CPU 41 executes the drive control program 43 c to perform drive control of the fixed base rotation motor 30 so as to rotate one roller electrode 27 by the rotation angle calculated by the rotation angle calculation unit 70. A drive control unit 71 is provided, and the drive control unit 71 functions as a drive control unit in the control device 4.
In the seam welding apparatus 2, when the CPU 41 executes the program creation program 43d, the drive control program 43c of the fixed base rotation motor 30 is rotated so as to rotate one of the roller electrodes 27 by the rotation angle calculated by the rotation angle calculation unit 70. The program creation unit 72 functions as a program creation unit in the control device 4.

<Seam welding method>
Next, a seam welding method using the seam welding robot system 10 including the seam welding apparatus 2 will be described.
As shown in FIG. 4, when seam welding is performed on the workpiece W using the seam welding robot system 10 including the seam welding apparatus 2, the CPU 41 executes a predetermined operation control program, thereby the two roller electrodes 25. , 27, the servo motor 15 is driven so as to sandwich the workpiece W (step S1: driving process). Specifically, the piston rod 24a of the air cylinder 24 is extended, and the movable base 23 is moved downward along the guide rail 22 by the piston rod 24a, so that the two roller electrodes 25 and 27 are mounted on the mounting base S. Insert the placed work W.
Next, when performing seam welding, the CPU 41 further extends the piston rod 24a of the air cylinder 24 and pressurizes the workpiece W by the two roller electrodes 25 and 27 (step S2: pressurizing step).

Next, the CPU 41 supplies a current necessary for welding to the two roller electrodes 25 and 27 by executing a predetermined energization control program (step S3: energization process). When energizing the two roller electrodes 25 and 27, the energization ON / OFF timing is appropriately switched by the energization control program. Since this timing changes according to the shape, material, etc. of the workpiece W, it is set in advance by the user before welding.
Next, the CPU 41 drives the electrode rotation motors 26 and 29 to rotate the roller electrodes 25 and 27 in the opposite directions at the same speed, and moves the robot 1 in the surface direction of the workpiece W (X direction in FIG. 1). (Step S4: 1st rotation drive process).

Next, the CPU 41 determines whether or not the weld line at the location to be welded is a curve in the read operation control program (step S5). In addition, a weld line means the line which shows the track | orbit of seam welding. Here, when the CPU 41 determines that the welding line is a curve (step S5: YES), the CPU 41 calculates the curvature of the welding curve, and calculates the rotation angle of the roller electrode 27 based on the calculated curvature ( Step S6: rotation angle calculation step). Here, the curvature of a welding curve calculates | requires a curvature based on the welding curve which calculates | requires a welding curve from the position coordinate data memorize | stored in the operation control program. On the other hand, when the CPU 41 determines that the welding line is not a curve (step S5: NO), the CPU 41 determines whether or not the welding is finished (step S9). When the CPU 41 determines that the welding has been completed (step S9: YES), the CPU 41 terminates this process, and when the CPU 41 determines that the welding has not been completed (step S9: NO), the CPU 41 performs the step The process returns to S5.
Next, the CPU 41 executes the program creation program 43d to create a drive control program 43c for the fixed base rotation motor 30 so as to rotate the roller electrode 27 by the calculated rotation angle based on the calculated angle ( Step S7).

(Drive control program creation method)
Here, a method of creating the drive control program 43c by the program creation program 43d will be described.
As shown in FIG. 5, when the CPU 41 executes the program creation program 43d, the CPU 41 executes the teaching program 43a for operating the robot 1, thereby causing the robot 1 to perform a teaching operation (step S11: teaching process).
Next, the CPU 41 records the teaching operation information of the robot 1 in step S11 in the memory 42 (step S12: recording step).
Next, the CPU 41 calculates the curvature of the welding curve to be welded in a curved shape on the workpiece W based on the teaching operation information of the robot 1 recorded in the memory 42 in step S12 (step S13: curvature calculation step).

Next, the CPU 41 calculates the rotation angle around the Z axis of the roller electrode 27 provided on the fixed base 28 rotated by the fixed base rotation motor 30 from the curvature of the welding curve calculated in step S13 (step S14: rotation). Angle calculation step).
Next, the CPU 41 creates a drive control program 43c for the fixed base rotation motor 30 based on the rotation angle calculated in step S14 (step S15: program creation step).
Next, the CPU 41 updates the drive control program 43c stored in the memory 42 to the new drive control program 43c created in step S15 (step S16), and this process is terminated.
The drive control program 43c may be a program that updates a program stored in the memory 42 in advance, or a program that is newly created.

Returning to the flowchart of FIG. 4 again, after the drive control program 43c is created, the CPU 41 executes the drive control program 43c created by the program creation program 43d, thereby driving the fixed base rotation motor 30 to The roller electrode 27 is rotated around the Z axis (see FIG. 1) by the rotation angle calculated in step S6 (step S8: drive control process).
Next, the CPU 41 determines whether or not the welding is finished (step S9). When the CPU 41 determines that the welding has been completed (step S9: YES), the CPU 41 terminates this process, and when the CPU 41 determines that the welding has not been completed (step S9: NO), the CPU 41 performs the step The process returns to S5.

<Advantages of rotating the roller electrode>
Next, the merit of rotating the roller table 27 by rotating the fixed table 28 by the fixed table rotating motor 30 will be described.
Fig.6 (a) is a figure which shows a weld line. The workpiece W is welded by moving the seam welder 3 along the weld line while rotating the energized roller electrodes 25 and 27. As shown in FIG. 6B, the weld line is a straight line L1. Compared to the case of (dotted line), when the curve L2 (dashed line) is obtained, the frictional force between the roller electrodes 25 and 27 and the workpiece W increases, and a large load is applied when the seam welding machine 3 is moved. However, the addition is reduced by rotating the roller electrode 27.

  The specific principle will be described. As shown in FIG. 7, when the rotation axis of the roller electrode 25 and the rotation axis of the roller electrode 27 are the same, the forces F1 and F2 applied to the workpiece W by the roller electrodes 25 and 27 are as follows. Each work in the same direction. Accordingly, since the work W is also sent in the same direction as the forces F1 and F2 at which the roller electrodes 25 and 27 send the work W, the frictional force does not increase. However, when the weld line is a curve and a force such as forces F1 and F2 is applied to the workpiece W, the direction in which the seam welder 3 advances and the direction in which the workpiece W is pushed out are completely different. Must be moved against the forces F1 and F2, and a large force acts.

  However, by rotating the roller electrode 27 by the rotation angle θ, as shown in FIG. 8, the force F3 acting on the workpiece W is the force Fa applied to the workpiece W by the roller electrode 25 and the rotated roller electrode 27 is applied to the workpiece. This is the resultant force with the force Fb applied to W. Here, F1 in FIG. 7 and fa in FIG. 8 have the same size, and F2 in FIG. 7 and fb in FIG. 8 have the same size. As a result, when the weld line becomes a curve, the direction of the force acting on the workpiece W is rotated along the weld line by rotating the roller electrode 27, so that each roller electrode 25, 27 and the workpiece W The frictional force can be reduced.

<Effect>
When performing seam welding, the servo motor 15 is driven so that the two roller electrodes 25 and 27 sandwich the workpiece W to drive the arm 14 (driving process), and a seam welding machine provided at the tip of the robot 1 The two roller electrodes 25 and 27 in FIG. 3 are brought into contact with the work W, and the two roller electrodes 25 and 27 are energized by the welding power source 5 (energization process).
The air cylinder 24 pressurizes one roller electrode 25 toward the other roller electrode 27 (pressurizing step). Then, the electrode rotation motors 26 and 29 cause the two roller electrodes 25 and 27 to pass through the centers of the roller electrodes 25 and 27 and around the axis substantially perpendicular to the radial direction of the roller electrodes 25 and 27 (Y axis in FIG. 1). The seam welding is performed by rotating around (first rotation driving step).
Here, when the CPU 41 of the control device 4 executes the rotation angle calculation program 43b, the CPU 41 causes the fixed base rotation motor 30 to rotate based on the curvature of the welding curve that is welded in a curved shape on the workpiece W. 29, the rotation angle of one roller electrode 27 provided at 29 is calculated (rotation angle calculation step). Then, the CPU 41 executes the drive control program 43c to perform drive control of the fixed base rotation motor 30 so as to rotate one of the roller electrodes 27 by the rotation angle calculated by the rotation angle calculation program 43b (drive control). Process). Thus, the fixed base rotation motor 30 rotates one of the roller electrodes 27 (second rotation driving process).
As a result, the fixed base rotation motor 30 moves in the tangential direction of the one roller electrode 27 passing through the contact point between the workpiece W and the one roller electrode 27 and in the rotation axis direction of the roller electrodes 25 and 27 by the electrode rotation motors 26 and 29. One roller electrode 27 can be rotated around a substantially orthogonal axis (around the Z axis in FIG. 1) based on the calculated angle.

That is, when the workpiece W is welded in a curved shape, a larger frictional force acts on the roller electrodes 25 and 27 than in the case of welding in a linear shape. In such a case, the fixed base rotation motor 30 is driven, and the one roller electrode 27 passes through the contact point between the workpiece W and the one roller electrode 27, and the tangential direction of the one roller electrode 27 and the electrode rotation motor 26, 29, the roller electrode 27 is rotated about an axis substantially orthogonal to the rotation axis direction of the roller electrode 27 (around the Z axis in FIG. 1), thereby moving the roller electrodes 25 and 27 in a tangential direction passing through the contact point with the workpiece W. The resultant force acts on the roller electrodes 25 and 27 in a direction different from the tangential direction passing through the contact point with the workpiece W. Therefore, by rotating the one roller electrode 27 by the calculated rotation angle by the fixed base rotation motor 30, a force along the weld line can be applied to the workpiece W.
Therefore, compared with the case where one roller electrode 27 is not rotated, the two roller electrodes 25 and 27 can be rotated without requiring a large force, reducing the burden on the operator when performing manually, Deformation prevention can be realized.

<Others>
The present invention is not limited to the above embodiment. For example, in the above embodiment, the seam welding device 2 is provided in the robot 1 and the workpiece W on the mounting table S provided on the floor or the like is welded, but at the tip of the arm 14 constituting the robot 1. An openable and closable hand is provided as a gripping means for gripping the workpiece W, the seam welding apparatus 2 is fixed to the floor, and the robot 1 is configured so that the workpiece W gripped by the hand is sandwiched between the roller electrodes 25 and 27 of the seam welding apparatus 2. It is good also as a structure which drives. In the case of such a configuration, in the process of performing seam welding, a gripping process of gripping the workpiece W with a hand provided in the robot 1 is necessary.
By adopting such a configuration, it is not necessary to support the seam welder 3 having a large weight at the tip of the arm 14 of the robot 1, thereby eliminating the deflection of the arm 14 caused by the weight of the seam welder 3. Thus, the positioning accuracy and welding accuracy of the robot 1 can be improved.

In addition to the curvature, the driving control program uses the welding speed of the robot 1, the pressure applied to the workpiece W by the air cylinder 24, the friction coefficient between the roller electrodes 25 and 27 and the workpiece W in combination with the curvature. 43c may be created. In such a case, the calculation accuracy of the rotation angle of the roller electrode 27 necessary for reducing the frictional force can be improved, which is preferable.
Further, not all of the processing is processed by software by a program, but part or all of the processing may be processed by hardware.
In addition, substitution and change are possible freely within the scope of the invention.

The schematic diagram of a seam welding machine, a seam welding apparatus, and a seam welding robot system. The block diagram which shows the structure of a seam welding machine, a seam welding apparatus, and a seam welding robot system. The block diagram which shows the function of a seam welding machine, a seam welding apparatus, and a seam welding robot system. The flowchart which shows the seam welding method by a seam welding robot system. The flowchart which shows the preparation method of a drive control program. The schematic diagram which shows a linear weld line and a curvilinear weld line. The figure explaining the force which acts on a workpiece | work when both roller electrodes are mutually parallel. The figure explaining the force which acts on a workpiece | work when one roller electrode is rotated.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Robot 2 Seam welding apparatus 3 Seam welding machine 4 Control apparatus (energization control means, drive control means, pressurization control means)
5 Welding power supply (power supply)
10 Seam welding robot system 14 Arm 15 Servo motor (drive means)
24 Air cylinder (Pressurizing means)
25 Roller electrode 26 Electrode rotation motor (first rotation drive means)
27 Roller electrode 29 Electrode rotation motor (first rotation drive means)
30 Fixed base rotation motor (second rotational drive means)
70 Rotation angle calculation unit (rotation angle calculation means)
71 Drive control unit (drive control means)
W Workpiece (workpiece)

Claims (9)

Two roller electrodes that are formed in a circular shape and perform seam welding on the workpiece by energizing the workpiece in contact with each other; and
A power source for energizing the two roller electrodes;
A pressing means for pressing one of the two roller electrodes toward the other roller electrode;
First rotation driving means provided on each roller electrode, and rotating each roller electrode about an axis that passes through the center of the roller electrode and is substantially orthogonal to the radial direction of the roller electrode;
One roller electrode is rotated about an axis substantially orthogonal to the tangential direction of the one roller electrode passing through the contact point between the workpiece and the one roller electrode and the rotation axis direction of the roller electrode by the first rotation driving means. Second rotation driving means for rotating
A seam welding machine comprising: Two roller electrodes that are formed in a circular shape and perform seam welding on the workpiece by energizing the workpiece in contact with each other; and
A power source for energizing the two roller electrodes;
A pressing means for pressing one of the two roller electrodes toward the other roller electrode;
First rotation driving means provided on each roller electrode, and rotating each roller electrode about an axis that passes through the center of the roller electrode and is substantially orthogonal to the radial direction of the roller electrode;
One roller electrode is rotated about an axis substantially orthogonal to the tangential direction of the one roller electrode passing through the contact point between the workpiece and the one roller electrode and the rotation axis direction of the roller electrode by the first rotation driving means. Second rotation driving means for rotating
A rotation angle calculating means for calculating a rotation angle of the one roller electrode rotated by the second rotation driving means based on a curvature of a welding curve to be welded in a curved shape in the workpiece;
Drive control means for performing drive control of the second rotation drive means so as to rotate the one roller electrode by the rotation angle calculated by the rotation angle calculation means;
A seam welding apparatus comprising:   The rotation angle calculation unit calculates a rotation angle of the one roller electrode rotated by the second rotation driving unit based on a curvature of the welding curve and a welding speed of the workpiece. Item 3. The seam welding apparatus according to item 2. A robot having an arm having a plurality of joints, and a driving means for driving the arm;
Two roller electrodes that are provided at the tip of the arm, are formed in a circular shape and are energized in a state where they are in contact with the work piece, and perform seam welding on the work piece;
A power source for energizing the two roller electrodes;
A pressing means for pressing one of the two roller electrodes toward the other roller electrode;
First rotation driving means provided on each roller electrode, and rotating each roller electrode about an axis that passes through the center of the roller electrode and is substantially orthogonal to the radial direction of the roller electrode;
One roller electrode is rotated about an axis substantially orthogonal to the tangential direction of the one roller electrode passing through the contact point between the workpiece and the one roller electrode and the rotation axis direction of the roller electrode by the first rotation driving means. Second rotation driving means for rotating
A rotation angle calculating means for calculating a rotation angle of the one roller electrode rotated by the second rotation driving means based on a curvature of a welding curve to be welded in a curved shape in the workpiece;
Drive control means for performing drive control of the second rotation drive means so as to rotate the one roller electrode by the rotation angle calculated by the rotation angle calculation means;
A seam welding robot system comprising: A robot having an arm having a plurality of joints, a gripping means provided at a tip of the arm and gripping the workpiece, and a driving means for driving the arm;
Two roller electrodes that are seam welded to the workpiece by being energized in a state of being fixed to the floor, formed in a circular shape and in contact with each other,
A power source for energizing the two roller electrodes;
A pressing means for pressing one of the two roller electrodes toward the other roller electrode;
First rotation driving means provided on each roller electrode, and rotating each roller electrode about an axis that passes through the center of the roller electrode and is substantially orthogonal to the radial direction of the roller electrode;
One roller electrode is rotated about an axis substantially orthogonal to the tangential direction of the one roller electrode passing through the contact point between the workpiece and the one roller electrode and the rotation axis direction of the roller electrode by the first rotation driving means. Second rotation driving means for rotating
A rotation angle calculating means for calculating a rotation angle of the one roller electrode rotated by the second rotation driving means based on a curvature of a welding curve to be welded in a curved shape in the workpiece;
Drive control means for performing drive control of the second rotation drive means so as to rotate the one roller electrode by the rotation angle calculated by the rotation angle calculation means;
A seam welding robot system comprising: In the seam welding method using the seam welding apparatus according to claim 2,
An energization step of energizing the two roller electrodes by the power source;
A pressing step of pressing the one roller electrode toward the other roller electrode by the pressing means;
A first rotation driving step of rotating each roller electrode about an axis that passes through the center of the roller electrode and is substantially orthogonal to the radial direction of the roller electrode by the first rotation driving means;
Rotation angle calculation for calculating a rotation angle of the one roller electrode rotated by the second rotation drive unit based on a curvature of a welding curve to be welded in a curved shape in the workpiece by the rotation angle calculation unit. Process,
The drive control means causes the one roller electrode to pass through the contact between the workpiece and the one roller electrode by the rotation angle calculated by the rotation angle calculation means, and the tangential direction of the one roller electrode and the first A drive control step of performing drive control of the second rotation drive means so as to rotate about the axis substantially orthogonal to the rotation axis direction of the roller electrode by the one rotation drive means;
A seam welding method comprising: In the seam welding method using the seam welding robot system according to claim 4,
A driving step of driving the arm to the position where the two roller electrodes sandwich the workpiece by the driving means;
An energization step of energizing the two roller electrodes by the power source;
A pressing step of pressing one roller electrode toward the other roller electrode by the pressing means;
A first rotation driving step of rotating each roller electrode about an axis that passes through the center of the roller electrode and is substantially orthogonal to the radial direction of the roller electrode by the first rotation driving means;
Rotation angle calculation for calculating a rotation angle of the one roller electrode rotated by the second rotation drive unit based on a curvature of a welding curve to be welded in a curved shape in the workpiece by the rotation angle calculation unit. Process,
The drive control means causes the one roller electrode to pass through the contact between the workpiece and the one roller electrode by the rotation angle calculated by the rotation angle calculation means, and the tangential direction of the one roller electrode and the first A drive control step of performing drive control of the second rotation drive means so as to rotate about the axis substantially orthogonal to the rotation axis direction of the roller electrode by the one rotation drive means;
A seam welding method comprising: In the seam welding method using the seam welding robot system according to claim 5,
A gripping step of gripping the workpiece by the gripping means;
A driving step of driving the arm by the driving means to a position where the work piece gripped by the gripping means is sandwiched between the two roller electrodes;
An energization step of energizing the two roller electrodes by the power source;
A pressing step of pressing one roller electrode toward the other roller electrode by the pressing means;
A first rotation driving step of rotating each roller electrode about an axis that passes through the center of the roller electrode and is substantially orthogonal to the radial direction of the roller electrode by the first rotation driving means;
Rotation angle calculation for calculating a rotation angle of the one roller electrode rotated by the second rotation drive unit based on a curvature of a welding curve to be welded in a curved shape in the workpiece by the rotation angle calculation unit. Process,
The drive control means causes the one roller electrode to pass through the contact point between the workpiece and the one roller electrode by the rotation angle calculated by the rotation angle calculation means and the tangential direction of the one roller electrode and the first A drive control step of performing drive control of the second rotation drive means so as to rotate about an axis substantially orthogonal to the rotation axis direction of the roller electrode by the rotation drive means;
A seam welding method comprising: In the seam welding robot system according to claim 4 or 5, in the rotation drive control program creation method of the roller electrode,
A teaching step for causing the robot to perform a teaching operation based on a teaching program for operating the robot;
A recording step of recording robot teaching operation information in the teaching step;
A curvature calculating step of calculating a curvature of a welding curve in which welding is performed in a curved shape in the workpiece based on teaching operation information of the robot recorded in the recording step;
A rotation angle calculation step of calculating a rotation angle of the one roller electrode rotated by the second rotation driving unit based on the curvature calculated by the curvature calculation step;
A program creation step of creating a drive control program of the second rotation drive means so as to rotate the one roller electrode by the rotation angle calculated by the rotation angle calculation step;
A method for creating a roller electrode rotation drive control program.

Images