KR100765832B1 - Robot laser welding method - Google Patents

Abstract

A robot laser welding method which can shorten the welding time as a whole by attaching a laser beam transmitting remote welding head which has a long focal length and is driven in three axes to an operation end of a welding robot and enabling the remote welding head to irradiate laser beams onto determined welding positions while the robot moves is provided. In a laser welding system comprising a laser oscillator; an articulated robot; a laser beam irradiator including an X-axis reflection mirror(31), an X-axis reflection mirror drive motor(32), a Y-axis reflection mirror(33), and a Y-axis reflection mirror drive motor(34); and a controller, a robot laser welding method comprises: allowing the controller to rotate the x-axis reflection mirror drive motor and the y-axis reflection mirror drive motor in a forward direction with respect to a transfer direction of the articulated robot in case of the welding regions; and allowing the controller to rotate the x-axis reflection mirror drive motor and the y-axis reflection mirror drive motor in a reverse direction with respect to the transfer direction of the articulated robot in case of regions between the welding regions when a plurality of welding regions which have a predetermined length and are formed in a predetermined distance therebetween are formed on a transfer path for performing a welding operation of the articulated robot.

Description

Robot Laser Welding Method {ROBOT LASER WELDING METHOD}

1 is an overall schematic view of a robot laser welding system according to the present invention.

2 is a conceptual view illustrating the operation of the robot laser welding system according to the present invention.

3 is an exemplary welding process for calculating a predicted value

4 and 5 is an operation flowchart illustrating an example of a control process of the robot laser welding system according to the present invention.

6 is an illustration of a typical robot laser welding system

7 and 8 is an exemplary view of a conventional welding head

     <Explanation of symbols for main parts of the drawings>

1: laser oscillator 4: optical cable

5: body 20: robot

30: remote welding head 31: reflection mirror in the X-axis direction

32: X-axis driving motor 33: Y-axis reflection mirror

34: Y-axis drive motor

The present invention relates to a robot laser welding method, and in particular, a three-axis drive laser beam transmission remote head having a long focal length is attached to a working end of a welding robot, and the robot optimizes a certain teaching section in which welding lines are arranged without stopping. When moving at speed, the remote head is intended to allow the laser beam to be irradiated to a defined welding position while the robot is moving.

In general, laser processing techniques have been widely used to join automobile bodies and the like, and the representative technical literatures thereof include Patent Nos. 0024847 and Patent No. 0447923.

The welding robot moves by welding the welding torch attached to the robot arm in accordance with the operation command to weld while following the welding line of the welding object. Referring to FIG. 6 attached to the configuration of the welding robot, the vehicle body 5 is welded. Laser welding equipment is a multi-joint robot (2) for performing a welding operation, a laser oscillator (1) for generating a laser beam, an optical cable (4) for transmitting the generated laser beam, and the transmitted laser beam to the body of the welding object ( It consists of a welding head 3 incorporating an optical system configured to focus on 5).

The welding method using the welding robot configured as described above is largely classified into two types according to the welding head type. The first welding method is a one-point welding method, and the second welding method is a group welding method.

FIG. 7 is an exemplary view for explaining an example of the fixed welding head 3a and the welding operation thereof according to the one-point welding method. Referring to the welding method together with the attached FIG. 6, the vehicle body 5 that is a welding object. The laser beam ON signal is assigned to the start point s and the laser beam OFF signal is assigned to the end point e by teaching the start point s and the end point e of the welding point on the robot program for the predetermined welding section of.

In FIG. 7, the entire welding section is not described. However, when the welding section is determined, the above-described welding operation repeatedly occurs within the welding section, and when the robot program according to the one-point welding method is operated, the robot ( 2) performs a welding operation by moving the position once for each welding point.

In addition, the fixed welding head 3a is a focus lens (not shown) for focusing the surface of the vehicle body 5 so that the laser beam incident through the optical cable 4 can increase the energy density for welding the vehicle body 5. It is composed of

The group-specific welding method corresponding to the one-point welding method described above uses a welding head 3b as shown in FIG. 8, and after setting a plurality of welding points to one welding group, the welding head 3b. ) Moves to the center of the welding group to perform welding for multiple welding points located in the group, and when the welding is completed, moves to the center of another welding group.

Among the two welding methods described above, the one-point welding method is performed by the robot from the welding start point (s) to the welding end point (e) within a predetermined welding section. It is a section, and the welding section has a merit that it is possible to implement the teaching speed in the robot program because it is a low speed movement even if the length is short.

On the other hand, if you want to move from one welding point to another, the moving speed moves quickly. Even though you set it to move at high speed in the robot program, there is a limit to speeding up the actual moving speed because the moving section is short. In practice, a problem arises in that the overall welding time becomes long.

This problem occurs because most of the industrial robots 2 driving the fixed welding head 3a are manufactured for the purpose of driving large loads. Because you can't.

On the other hand, in the above-mentioned two welding methods, the welding method for each group has a movement from the welding end point e to another welding start point s in the area where the welding head 3b is workable compared to the one point welding method. Only by moving the motor within) has the advantage that it can move at maximum speed by maximizing acceleration / deceleration.

Therefore, compared to the one-point welding method, the moving time is reduced and the overall working time can be reduced. However, the welding head 3b can be welded only in a limited welding group area, and thus the welding head 3b can be moved from one welding group to the next. The process is inevitably dependent on the acceleration / deceleration capability of the industrial robot 2 in the same way as the one-point welding method described above.

The present invention corrects the above problems, and when the three-axis drive laser beam transmission remote head having a long focal length is attached to the working end of the welding robot, and the robot moves at a constant teaching interval where the welding line is arranged at an optimum speed without stopping. The remote head is intended to provide a robot laser welding method for shortening the overall welding time by allowing the laser beam to be irradiated to a predetermined welding position while the robot is moving.

In order to achieve the above object, the present invention comprises a laser oscillator for generating a laser beam that can be transmitted through an optical fiber, and a multi-joint robot that receives a laser beam transmitted from the laser oscillator and is movable relative to a welding work section for welding. In the laser welding system for irradiating and bonding a laser beam to the object, located on one side of the arm of the articulated robot, the laser beam generated by the laser oscillator is received through a plurality of rotatable mirror to change the course A controller for controlling the laser beam irradiator in synchronization with a laser beam irradiator configured to irradiate a laser beam to an outgoing mirror with respect to a welding point in accordance with the direction and speed of the articulated robot; and a robot controller for controlling the articulated robot. It is configured to include.

In order to achieve the above object, the controller of the present invention is to synchronize the welding speed to the feed speed of the articulated robot to drive the laser beam irradiator.

In order to achieve the above object, the laser beam irradiator of the present invention receives the laser beam generated by the laser oscillator and reflects in the X-axis direction, and rotates the X-axis reflection mirror in the forward or reverse direction The X-axis reflecting mirror driving motor to adjust the reflection angle, the Y-axis reflecting mirror which receives the laser beam reflected from the X-axis reflecting mirror and reflects it in the Y-axis direction, and rotates the Y-axis reflecting mirror in the forward or reverse direction. It includes Y-axis reflective mirror driving motor to adjust the reflection angle.

In order to achieve the above object, in the case of having a plurality of welding regions having a constant distance and a certain length on the feed path for the welding operation of the articulated robot of the present invention, the controller is the laser in the case of a welding region The X-axis reflective mirror driving motor and the Y-axis reflective mirror driving motor of the light irradiator are rotated in the forward direction in accordance with the feeding direction of the articulated robot, and in the case of a spaced area between the welding area and the welding area, the X-axis reflection of the laser beam irradiator The mirror drive motor and the Y-axis reflective mirror drive motor are rotated in the opposite direction to the conveying direction of the articulated robot.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail.

1 is an overall schematic view of a robot laser welding system according to the present invention, and FIG. 2 is a schematic diagram illustrating a robot laser welding system according to the present invention.

Referring to FIG. 1, the constitution includes a multi-joint robot 20 for performing a welding operation, a laser oscillator 1 for generating a laser beam, an optical cable 4 for transmitting the generated laser beam, and a transmitted laser. It consists of a synchronized remote welding head 30 incorporating a beam transmission optical system capable of three-dimensional driving configured to focus the beam on the welding target vehicle body 5.

The overall configuration is not significantly different from the prior art, the difference in the configuration is in the remote welding head 30, the operation state between the remote welding head 30 and the robot 20 having a configuration difference with the prior art is synchronized with each other. It is done.

Referring briefly with reference to Figure 2 attached to such a technical difference, the robot 20 moves without stopping motion over the working section of the welding target object 5 at a moving speed that can be synchronized with the remote welding head 30. do.

At this time, the X-axis reflection mirror 31 and the X-axis driving motor 32, the Y-axis reflection mirror 33 and the Y-axis driving motor 34 in the remote welding head 30 performs the synchronous operation. .

In the case of the welding section, the rotational driving (forward direction) of the motor is made at the speed that can be welded in the same direction as the moving direction of the robot, and at the same time as the welding ends, each motor is driven in the opposite direction to the rotational direction during welding to return to the origin.

When the time point of another welding section is reached again, the above-described operation is repeatedly performed, and the setting of the factor is set by theoretical calculation so as to achieve the optimum synchronous control.

That is, while the robot 20 moves at a constant speed, the reflection mirror drive motors 32 and 34 of the remote welding head 30 rotate in the same welding direction as the moving direction of the robot 20 in the welding section. While irradiating the laser beam, the non-welded section (moving section) is rotated at the maximum speed in the reverse direction to the moving direction of the robot 20 to return to the home position.

In order to achieve such an operation, that is, the setting of the factor to be the optimal synchronous control, referring to FIG. 3 attached to the principle of theoretical calculation, the optimum driving speed of the robot should be predicted. Assuming that work is performed as shown in 3, a prediction equation for predicting an optimal driving speed of the robot may be defined by Equation 1 below.

[Equation 1]

Looking at the factor of Equation 1, Vr (mm / s) is the robot driving speed, L (mm) is the robot driving section length, Lw (mm) is the welding length, Vw (mm / s) is welding Speed, Lp (mm) is pitch length, Vp (mm / s) is pitch speed, Td (s) is laser beam ON time delay time at welding time, and Tw = Lw (n) / Vw (n) Weld section work time, Tp = Lp (n-1) / Vp (n-1) is pitch section work time.

The theoretical value of each control factor is calculated based on the above equation, and the robot 20 is capable of synchronizing with the remote welding head 30 based on this.

Therefore, in the welding method according to the present invention, the robot 20 continues to move without stopping operation by teaching work points for a predetermined welding section of the vehicle body 5, which is a welding object, and the remote welding head 30 has a predetermined welding position. In order to accurately irradiate the laser beam to the welding start point and end point, the welding is performed by synchronizing with the moving speed of the robot 20 to perform the teaching work.

That is, the robot 20 can perform high-speed welding only by the individual welding of the remote welding head 30 during the movement, as long as the robot 20 moves at a predetermined speed, so that the robot 20 can perform independent welding work without depending on the control device such as the robot 20. There is a big advantage to that.

4 and 5 are operational flowcharts illustrating an example of a control process of the robot laser welding system according to the present invention. FIG. 4 is an operational flowchart relating to an overall welding operation, and FIG. 5 is a welding diagram. The operation is terminated and moves to the next welding position, while the reflection mirrors 31 and 33 of the remote welding head 30 return to their original positions, and the detailed description thereof will be omitted.

In addition, although not shown, the driving motor 32 rotates the reflection mirrors 31 and 33 of the remote welding head 30 in synchronization with a robot controller that controls the movement of the robot 20 and the movement of the joint. This is done by the controller that controls it.

While the invention has been shown and described in connection with specific embodiments thereof, it is well known in the art that various modifications and changes can be made without departing from the spirit and scope of the invention as indicated by the claims. Anyone who owns it can easily find out.

As described above, the present invention attaches a three-axis driving laser beam transmission remote welding head having a long focal length to the working end of the welding robot, and the remote welding head when the robot moves at an optimum speed without stopping a certain teaching section in which the welding line is arranged. Since the laser beam can be irradiated to a predetermined welding position while the robot is moving, the welding time can be dramatically shortened, thereby improving productivity.

Claims (4)

A laser oscillator for generating a laser beam that can be transmitted through an optical fiber, and a multi-joint robot that receives the laser beam transmitted from the laser oscillator and is movable for a welding work section. In the welding system, Located on one side of the arm of the articulated robot, the laser beam generated by the laser oscillator is received through a plurality of rotatable mirrors to change the path and then emit light to the welding point according to the feeding direction and speed of the articulated robot. A laser beam irradiator configured to irradiate a laser beam with a mirror, And a controller for controlling the laser beam irradiator in synchronization with a robot controller for controlling the articulated robot. The laser beam irradiator includes an X-axis reflecting mirror which receives the laser beam generated by the laser oscillator and reflects it in the X-axis direction; An X-axis reflection mirror driving motor for adjusting the reflection angle by rotating the X-axis reflection mirror in a forward or reverse direction; A Y-axis reflection mirror which receives the laser beam reflected from the X-axis reflection mirror and reflects it in the Y-axis direction, and And a Y-axis reflection mirror driving motor configured to rotate the Y-axis reflection mirror in a forward or reverse direction to adjust a reflection angle. In the case of having a plurality of welding regions having a predetermined distance and a certain length on the transfer path for the welding operation of the articulated robot, In the welding area, the controller rotates the X-axis reflective mirror driving motor and the Y-axis reflective mirror driving motor of the laser beam irradiator in a forward direction in accordance with the transfer direction of the articulated robot, In the case of the separation area between the welding area and the welding area, the robot laser welding, wherein the X-axis reflective mirror driving motor and the Y-axis reflective mirror driving motor of the laser beam irradiator are rotated in a direction opposite to the conveying direction of the articulated robot. Way. The robot laser welding method according to claim 1, wherein the controller drives the laser beam irradiator by synchronizing a welding speed to a feed speed of the articulated robot. delete delete

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