JPS6340677A - Welding robot with sensor - Google Patents

Abstract

PURPOSE:To improve the welding strength by allowing a welding robot to weave corresponding to a weld line position and the gap width detected by an optical sensor to perform the welding with the wide bead width on a place with a gap. CONSTITUTION:Spot light 5a from a projection part 1a is projected on a lap joint work 4 and a range finder 1 is oscillated and turned round a welding torch 7 via a stepping motor 3 and an oscillating mechanism 2 and reads the distance data of a distance measurement part 5 to cross a weld line 6 at a prescribed interval. Information on the weld line position and the gap width obtained by a sensor control part 12 is inputted to a robot control part 13 and the weaving is performed on the gap part to perform the welding with the wide bead width and strength. When the position of the robot is coincident with the weld line position stored in a memory of the control part 13, the profile quantity is calculated and the robot is moved to the next weld line position.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a sensor-equipped welding robot.

BACKGROUND OF THE INVENTION In recent years, welding robots have come to be equipped with sensors in order to cope with welding objects (hereinafter referred to as welding workpieces) that are misaligned or have poor dimensional accuracy. The main sensors are arc sensors and optical sensors. The arc sensor detects the weld line position from fluctuations in arc current and voltage during weaving welding, and traces the weld line on medium-thick plate workpieces. In addition, conventional optical sensors obtain a shape by projecting spot light or slit light onto a welding workpiece, and detect the weld line position from the shape, and can be applied to thin plates.

Problems to be Solved by the Invention In the case of arc sensors, they cannot be applied to thin plate welding workpieces where fluctuations in arc current and voltage are small.

There were problems such as the inability to form a straight, clean weld bead without weaving, and the range of its application was narrow.

In addition, conventional optical sensors detect the position of the weld line and follow it to form a straight, relatively narrow weld bead, so it may not be possible to perform strong and normal welding at the gap, which may result in a later process. After inspection, 11 repairs were required.

Means for Solving the Problems In order to solve the above problems, the present invention provides an optical sensor for detecting the position of a weld line and the gap width.

A first means for determining the presence or absence of weaving and the size of the weaving width in response to the detected gap width, and a second means for weaving based on the weaving width determined by the first means. This is what happens.

Weaving is performed where there is a gap in the working weld line and welding with a wide bead allows for strong and normal welding.

Embodiment An embodiment of the present invention will be explained with reference to FIGS. 1, 2, and 3. FIGS. 1, 2, and 3 are a perspective view of a main part of a sensor-equipped welding robot according to this embodiment, a diagram of a shape detected by an optical sensor, and a block diagram of a control device that processes sensor data, respectively.

In FIG. 1, 1 is an optical rangefinder, and 1a is a light projector.

1b is a light receiving part, 2 is a swinging mechanism for swinging the optical sensor,
3 is a stepping motor for swinging.

4 is lap joint work! 5 is a distance measuring unit, 5a is a spotlight, 6 is a welding line of the lap joint work 4, 7 is a welding torch, 8 is a welding bead, 9 is a welding torch holder, 10 is a mounting pace, 11 is a robot wrist rotation unit, 12 13 is a sensor control section, 13 is a robot control section, and 14 is a robot body. The operation of the sensor-equipped welding robot configured as described above will be explained below. An optical distance meter 1 that projects a spot light 6a from a light projector 1a onto the surface of an overlapping joint work 4, receives the reflected light in a light receiver 1b, and detects the distance from the image formation position of the elephant on the light receiver. is oscillated around the welding torch 7 via the oscillating mechanism 2 by the stepping motor 3,
If the distance data of the distance measuring part 6 that crosses the welding line 6 is obtained sequentially at regular intervals of 0.1 or 0.2, a shape as shown in FIG. 2 is obtained. In Figure 2, a is the weld line shape of the part without a gap, b and C are the weld line shapes of the part with a gap,
The recognition unit 12a of the sensor control unit 12 in FIG. 3 uses the microcomputer to determine the welding line position P1'! ! or P2 or P3 are obtained as coordinates of the scanning position and distance. Welding line positions P1 and P3
is obtained as a feature point by taking the difference between the distance data, and P2 is a point where the distance cannot be detected correctly due to the small amount of light received due to reflection from the gap, so it is a feature point Q.
2 is detected, and the subsequent two straight lines are determined and obtained as their intersection. In the case of b, the gap width is detected based on the small number of data, and in the case of C, the change in distance data is large near the weld line position, so it can be detected from the number of data with a large difference value. .

Furthermore, b and C can also be obtained from the distance between two straight lines tilted in the direction of the arrow. At this time, the size diameter of the spot light 6a is 0.
Detection accuracy is better below 6m+11. In FIG. 3, the weld line position and gap width obtained by the recognition unit 12a of the sensor control unit 12 are communicated to the data processing unit 13a from the sensor of the robot control unit 13.

Therefore, the current position calculation unit 13 calculates the welding line position using a microcomputer.
Combined with the robot position data from b, converted to the robot's general coordinate system, and then set the gap width to a constant (e.g. 0.5 mm) registered in the microcomputer's processing program in advance.
Select weaving conditions such as weaving width and weaving speed from the table according to how many times
3 Store in c.

When the gear width is less than a predetermined constant in the weaving condition table, the condition is set to no weaving, thereby determining the presence or absence of weaving and the size of the weaving width based on the gap width. If the current position of the robot matches the welding line position stored in the memo IJ 13C, data on the next welding line position is sent to the operating position calculation unit 13d by the microcomputer provided in the current position calculation unit 13b. The operating position calculation section 13d calculates and combines the tracing and weaving amounts for moving to the next welding line position, and sends the data to the servo 10 and both sections 13e. 13e operates the robot body 14.

Note that fillet joint work and butt joint work can also be welded in the same way.

Further, as an optical sensor, the same operation can be performed even if a slit light is projected.

Effects of the Invention As explained above, according to the present invention, it is possible to perform copying and weaving by detecting the weld line position and the width of the gap using an optical sensor, so it can be applied to welded workpieces of thin plates with gaps, and the strength can be improved. Can do some normal welding. This greatly reduces the amount of inspection and rework required in post-processing.

Therefore, the scope of application is expanded. Furthermore, if the gap width is large, it can also be detected as an abnormal workpiece. As described above, the practical effects of the present invention are significant.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the main parts of a sensor-equipped welding robot according to the present invention, FIG. 2 is a diagram of a shape detected by an optical sensor of the robot, and FIG. 3 is a block diagram of a control device that processes sensor data. 1... Optical distance meter v2... Rocking mechanism,
3... Stepping motor, 4... Lap joint work, 6... Distance measuring part v6...
...Welding lines 1, 7...Welding torch, 8...
...Welding bead, 12...Se/su control section, 12
a...Recognition unit, 13...Robot control unit, 13a...Data processing unit from sensor, 1
3b...Currently r position calculation section, 13e...
- Servo control section, 14...Robot body. Name of agent: Patent attorney Toshio Nakao 1 person 7-
−・fY−chi8−−−=, 3−4y Fig. 2

Claims (1)

[Claims] In a sensor-equipped welding robot that is equipped with a sensor that detects a weld line and a weaving function, an optical sensor that detects the position and gap width of the weld line, and a sensor that detects the presence or absence of weaving and the weaving width according to the size of the detected gap width. 1. A welding robot with a sensor, comprising: a first means for determining the size of the welding robot; and a second means for weaving based on the weaving width determined by the first means.