JP2022128720A - Tailored blank welding device - Google Patents

Abstract

To provide a tailored blank welding device capable of suppressing deterioration of weld quality compared with the past.SOLUTION: When a temperature change of a robot 20 exceeds a prescribed threshold, a control device 50 calculates a deviation amount of a welding target position by the robot 20 based on a processing result of a welding trajectory image by a camera 40, and corrects the welding target position of the robot 20. Therefore, even when the robot 20 is deformed owing to outdoor temperature change caused by seasonal fluctuation or linear expansion caused by heat generation during operation of the robot 20, deviation of the welding target position can be corrected, to thereby suppress deterioration of weld quality.SELECTED DRAWING: Figure 1

Description

The present invention relates to a tailored blank welding device.

2. Description of the Related Art There is a tailored blank welding apparatus that manufactures a raw material for pressing (tailored blank) by butting together workpieces having different thicknesses and materials and line-welding the abutted portions (see, for example, Patent Document 1).

By the way, the welding quality of the tailored blank is maintained by accurately irradiating the boundary line between the butted workpieces with the laser. In particular, in tailored welding by robots, quality is controlled by fine adjustments of a few tenths of a millimeter through teaching work.

However, in general, robots are constructed of metal. Therefore, as shown in FIG. 7, the length of the robot arm 2a of the robot 2 changes from the state D1 indicated by the solid line to the state D2 indicated by the dotted line due to linear expansion due to fluctuations in outside temperature due to seasonal fluctuations and heat generated by the motor during operation of the robot. . This is because it is difficult to keep the temperature inside the processing machine constant during welding for equipment reasons, and because it is difficult to manufacture the robot 2 from members having a small coefficient of linear expansion. As a result, the welding target position of the robot 2 may deviate from the position T1 indicated by the solid line, which is taught here, to the position T2 indicated by the dotted line.

JP 2009-262193 A

SUMMARY OF THE INVENTION An object of the present invention is to provide a tailored blank welding apparatus capable of suppressing deterioration of welding quality as compared with the conventional one.

The present invention for achieving the above object is as follows.
(1) a robot that butts the first and second workpieces and welds the butted parts;
a temperature measuring device that measures the temperature of the robot;
a camera that captures the welding trajectory of the robot and acquires the image;
a control device that controls the robot, the temperature measurement device and the camera;
has
When the temperature change of the robot exceeds a predetermined threshold, the control device calculates the amount of deviation of the welding target position of the robot based on the processing result of the welding trajectory image by the camera, and calculates the welding target position of the robot. Tailored blank welding equipment that corrects the position.
(2) The tailored blank welding apparatus according to (1), wherein a correction value is automatically input to the control device based on the amount of deviation of the welding target position.

According to the tailored blank welding apparatus of (1) above, when the temperature change of the robot exceeds a predetermined threshold, the control device determines the amount of displacement of the welding target position by the robot based on the processing result of the welding trajectory image by the camera. is calculated and the welding target position of the robot is corrected. Therefore, even if the robot deforms due to changes in outside temperature due to seasonal fluctuations or linear expansion due to heat generated during operation of the robot, the deviation of the welding target position can be corrected. Therefore, deterioration of welding quality can be suppressed.

According to the tailored blank welding apparatus of (2) above, since the correction value is automatically input to the control device based on the amount of displacement of the welding target position, the robot needs to be taught again every time the welding target position is displaced. It becomes unnecessary, and the productivity of tailored blanks can be improved.

1 is a schematic configuration diagram of a tailored blank welding apparatus according to an embodiment of the present invention; FIG. FIG. 2 is a partial plan view of first and second work materials to be welded by the tailored blank welding apparatus of the embodiment of the present invention; FIG. 4 is a side view showing the relationship between the laser beam of the robot and the imaging direction of the camera in the tailored blank welding apparatus of the embodiment of the present invention; It is a figure which shows the captured image of the camera of the tailored blank welding apparatus of this invention Example. FIG. 5 is a diagram for explaining that the amount of deviation due to linear expansion at each teaching point differs depending on the posture of the robot during welding in the tailored blank welding apparatus of the embodiment of the present invention; 4 is a flow chart showing a control routine of the control device in the tailored blank welding apparatus of the embodiment of the present invention; 1 is a schematic configuration diagram of a conventional tailored blank device; FIG.

A tailored blank welding device (hereinafter also simply referred to as a welding device) 10 of an embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 2, the welding device 10 line-welds first and second workpieces 101 and 102 made of, for example, steel plates having different plate thicknesses and materials, and line-welds the butted portions (butt portions 103). This is a device that manufactures a sheet of material for pressing (tailored blank). Materials manufactured from the first and second workpieces 101 and 102 are not particularly limited, but are used for automobile bodies for the purpose of reducing the weight of automobiles, for example.

As shown in FIG. 1, the welding apparatus 10 is a robot 20 that linearly laser-welds the first and second workpieces 101 and 102 along the butted portion 103 of the first and second workpieces 101 and 102. , a temperature measuring device 30 for measuring the temperature of the robot 20, a camera 40 for capturing the welding trajectory TR of the butted portion 103 and acquiring the image, and a control device for controlling the robot 20, the temperature measuring device 30 and the camera 40. 50 and

The robot 20 is taught in advance, and laser-welds the first and second workpieces 101 and 102 along the butted portion 103 by this teaching. The robot 20 has a robot arm 23 connected at its proximal end to a base 21 and having a laser head 22 attached at its distal end. The robot arm 23 is a multi-joint arm having first and second joints 23a and 23b and upper and lower arm portions 23c and 23d. A plurality of servo motors (not shown) are built in the robot arm 23, and by driving the robot arm 23 with the servo motors, the laser head 22 can be moved three-dimensionally.

As shown in FIG. 3, the laser head 22 irradiates the butted portion 103 of the first and second workpieces 101 and 102 with a laser beam L output from a laser oscillator (not shown). The laser head 22 has a collimating lens 22 a that converts the laser light L into parallel light, and a condenser lens 22 b that converges the parallel light so that it is focused at the abutting portion 103 . The laser head 22 also has a reflecting mirror (not shown) that can be rotated by a servomotor (not shown). A laser beam L output from a laser oscillator (not shown) passes through both lenses 22 a and 22 b, is reflected by a reflecting mirror, and irradiates the abutting portion 103 . By rotationally driving the reflecting mirror with a servomotor, the laser beam L can be rotationally moved so as to form a circular orbit. By controlling the robot arm 23 and the laser head 22 by the control device 50 , the irradiation position of the laser beam L can be spirally moved along the butted portion 103 .

As shown in FIG. 1 , a temperature measuring device (thermometer) 30 can measure the temperature of the robot arm 23 . The temperature measuring device 30 measures the temperature of the upper arm portion 23 c and/or the lower arm portion 23 d of the robot arm 23 . The temperature measuring device 30 may be a contact type such as a thermocouple, or a non-contact type such as an infrared radiation thermometer.

The camera 40 can image the laser-welded portion of the butted portion 103 and its surroundings. Therefore, at least part of the welding locus TR of the butted portion 103 can be imaged. The camera 40 images an area including a preset teaching point (imaging point) when welding. A plurality of teaching points are set on the line of matching portion 103. For example, 25 teaching points indicated by circled numbers 1 to 25 are set in FIG. The number and intervals of these teaching points can be set arbitrarily.

As shown in FIG. 3, camera 40 is attached to laser head 22 . Camera 40 images welding locus TR of butted portion 103 via first and second imaging mirrors 41 and 42 that reflect welding locus TR of butted portion 103 . Information of an image captured by the camera 40 is transmitted to the control device 50 via the image processing amplifier 43 as shown in FIG.

A control device (which may also be referred to as a robot control panel) 50 controls the welding target position of the robot 20 based on teaching performed in advance. In addition, the control device 50 calculates the amount of deviation of the actual welding position from the welding target position A taught in advance of the robot 20 based on the processing result of the welding trajectory TR image by the camera 40, and corrects it based on the calculation result. A value can be automatically input to correct the welding target position of the robot 20 .

The reason for calculating (measuring) the amount of deviation based on the processing result of the welding locus image by the camera 40 is as follows.
FIG. 5 shows (a ) robot 20, (b) a plurality of teaching points 1 to 11, (c) to (e) showing the amount of deviation due to linear expansion of the robot 20 at points 1, 4, and 9 among the plurality of teaching points 1 to 11. Graph, showing.

From (c) to (e) of FIG. 5, the robot 20 assumes various postures during welding, and it can be seen that the amount of deviation due to linear expansion at each teaching point 1, 4, 9 differs depending on the posture of the robot 20. Recognize. Therefore, it is effective to calculate (measure) the amount of deviation at each point because it cannot be dealt with by the same uniform correction. Therefore, the deviation amount is calculated (measured) based on the processing result of the welding trajectory TR image by the camera 40 .

FIG. 6 is a flow chart showing a control routine of the control device 50. As shown in FIG. The control routine shown in FIG. 6 is performed at predetermined time intervals while laser welding (welding) is being performed.

First, after starting laser welding, the temperature of the robot 20 is measured using the temperature measuring device 30 in step S1, and the process proceeds to step S2. In step S2, it is determined whether the temperature change of the robot 20 has exceeded a predetermined threshold. If it is determined in step S2 that the temperature change does not exceed the predetermined threshold value, the process proceeds to the end step without correcting the displacement of the welding target position. On the other hand, if it is determined in step S2 that the temperature change has exceeded the predetermined threshold value, the process proceeds to step S3.

In step S3, the welding trajectory TR is imaged using the camera 40, and the process advances to step S4 to calculate (measure) and obtain the deviation amount based on the image information imaged by the camera 40. FIG. Then, in step S5, a correction value is automatically input to the control device 50 in the direction of eliminating the amount of deviation, and the process proceeds to the end step.

Next, the operation and effect of the embodiment of the present invention will be explained.
In the embodiment of the present invention, when the temperature change of the robot 20 exceeds a predetermined threshold value, the control device 50 calculates the amount of deviation of the welding target position of the robot 20 based on the processing result of the welding trajectory image by the camera 40. Since the welding target position of the robot 20 is corrected, even if the robot 20 is deformed due to changes in the outside temperature due to seasonal fluctuations or linear expansion due to heat generated during operation of the robot 20, the deviation of the welding target position can be corrected. It is possible to suppress deterioration in quality.

In addition, since a correction value is automatically input to the control device 50 based on the amount of displacement of the welding target position, there is no need to redo the teaching of the robot 20 each time the welding target position is displaced, thereby increasing the productivity of tailored blanks. can be improved.

10 Tailored blank welding device 20 Robot 22 Laser head 23 Robot arm 30 Temperature measurement device 40 Camera 43 Image processing amplifier 50 Control device 101, 102 First and second workpieces 103 Butt part L Laser beam TR Welding trajectory

Claims (1)

a robot that butts the first and second workpieces and welds the butted parts;
a temperature measuring device that measures the temperature of the robot;
a camera that captures the welding trajectory of the robot and acquires the image;
a control device that controls the robot, the temperature measurement device and the camera;
has
When the temperature change of the robot exceeds a predetermined threshold, the control device calculates the amount of deviation of the welding target position of the robot based on the processing result of the welding trajectory image by the camera, and calculates the welding target position of the robot. Tailored blank welding equipment that corrects the position.

Images