KR880000652B1 - Device for detacting the first spot of arc welding robort - Google Patents

Abstract

Regardless of the surface state of weldded material and the quality of material, the high frequency signal of small current is applied to the weldded material to detect rapidly and precisely the initial point. The microprocessor makes the torch move up and down or left and right by sensing the high frequency signal and performs the weldding operation by detecting the initial point. The output of an oscillator (8) is amplified by an amplifier (9) in proper level and though a transformer (10) applied to the output part of the signal (11). The torch (6) is connected to the selection switch (5) which is manipulated by microprocessor of robot control system (1).

Description

Initial point detection device of arc welding robot

1 is a system configuration diagram of the present invention.

2 is an overall schematic diagram for initial point detection of the present invention.

3 is an example of the overall circuit of the present invention.

4 is a time chart diagram according to the present invention.

5 is an embodiment of a butt initial point detection method for explaining the present invention.

6 is an embodiment of a method for detecting an initial point of a horizontal filtrate for explaining the present invention.

Figure 7 is an embodiment of the initial point detection method of the vertical filtrate for explaining the present invention.

* Explanation of symbols for main parts of the drawings

3: welding machine, power supply 4: initial point detection device

5: selector switch 6: torch

8: oscillator 9: amplifier

10: transformer 11: signal output unit

12: TTL level generator 14: microprocessor

The present invention relates to an apparatus for detecting an initial welding start point of an arc welding robot of the present invention.

The conventional welding robot detects the initial point by using a proximity method, a contact method or a detection method using a light sensor, but the proximity method has a detection error depending on the type of the base metal. In the contact method, a detection error occurs according to the surface state of the base material, and the method by the light sensor inevitably causes a detection error due to the reflected light generated on the surface of the base material.

In addition, the algorithm used in the conventional welding robot (Algorithm) is only a simple contact and the angle of the part to be welded and the type of welding is not a separate one, there is a problem that its use is extremely limited.

In order to solve this problem, the microprocessor sends a high frequency signal of a small current to the base material and detects it so that the initial point can be detected accurately and quickly without regard to the surface state or material of the base material. Torch (Torch) to move up and down and left and right while detecting the initial point to perform a welding operation as described in detail by the accompanying drawings as follows.

1 relates to an entire robot system using the present apparatus.

The system consists of a robot controller 1, a robot body 2, a welding machine power supply 3, an initial point detection device 4, a selector switch 5, and a torch 6 and a substrate 7.

In this configuration, the initial point detecting device 4 according to the present invention is shown well through the overall schematic of FIG. 2 and the detailed circuit diagram of FIG.

According to this configuration, the output of the oscillator 8 is amplified to an appropriate level by the amplifier 9 and applied to the signal output unit 11 through the transformer 10, and the torch 6 is a microcomputer in the robot controller 1. The selector switch 5 operated by the processor 14 is connected so that it can be selectively connected to the signal output unit 11 or the welding machine power source 3, and the output of the signal output unit 11 is the TTL level generator 12. And the TTL level optical coupler 13 and connected to the input of the microprocessor 14, and the torch 6 is moved up and down and left and right by the output of the microprocessor 14 to detect the initial contact.

First, in the present invention, the condition for initial point detection is that the size of the base material 7, the shape of the welding line, the welding length, and the like are already programmed in the microprocessor 14 of the robot controller 1, and the base material 7 ) Is transported to the position set by the transport cart (not shown), etc., the position error of the transport cart on which the base material 7 is loaded is extremely small, so that the torch 6 tracks the position of the weld line initial point (ie, the center point). In this case, there is no large error in the left and right movement, and when the welding seam initial point is detected by the torch 6, the torch 6 performs welding by the microprocessor 14 of the robot controller 1.

In the present invention as described above, when the base material 7 is conveyed to the position set by the transfer balance as in the above conditions, the robot controller 1 sends an initial point detection command to the microprocessor 14 as shown in FIG. 4 (b). Will send a signal.

Then, the microprocessor 14 outputs a high level signal through the resistor R ₁ and the photodiode PD so that the phototransistor Q ₁ is turned on to turn on the transistor R ₂ and the relay R _y . Operate.

By operating the relay R _y , the selector switch 5 is connected to the connection point Rya.

Here, the main role of the selector switch 5 is used at the time of welding and the initial point detection. In particular, the foreign material and the oxidized iron plate adhered to the surface of the base material 7 from the initial point detection device 4 at the initial point detection. In order to make accurate contact, high voltage (400V) and high frequency (400Hz) are output. This voltage and frequency is installed to prevent backflow into the welding machine. If there is no selection switch 5, high voltage (400V) Since the semiconductor formed by flowing back into the welding power source 3 is destroyed, when the initial point is detected, it is switched to the connection point Rya and the closed circuit (a) is generated by the voltage and frequency generated by the initial point detection device 4. It is used to detect that the torch 6 and the base material 7 are stranded. When welding is performed, the welding power source 3, the torch 6, and the base material 7 are connected to the connection point Ry. Lung connecting And create it by (b).

On the other hand, the initial point detection device 4 is equipped with the operating conditions in the robot system and the oscillator 8 is operated, the oscillator signal (400Hz) of the oscillator 8 is amplified while passing through the amplifier 9 is a transformer ( To the secondary side of 10).

Therefore, the frequency signal induced on the secondary side of the transformer 10 is transmitted to the signal output unit 11 and applied to the torch 6, whereas on the base material 7 side, one end of the secondary side of the transformer 10 is grounded. The induced high frequency voltage is applied to the secondary side to flow.

Therefore, the microprocessor 14 of the robot controller 1 moves the torch 6 installed in the robot body 2 to the first point.

Here, the movement of the torch 6 to the first set point is performed by the program. The torch 6 is placed on the y axis, which is the end of the welding line of the base material 7, as shown in FIG. And move up and down to start the initial point detection operation.

The method for detecting the initial point by the present invention is divided into Butt (Butt) and Fillet (Fillet) when discussing the detailed processing method as follows.

First of all, in the case of the butt, as shown in FIG. 5, the form is only possible in four modes to find the center point of the weld seam at the current position of the torch 6. First, when the torch 6 is placed on the surface of the base material G ₁ and G ₂ as in the example of (a), the torch 6 is lowered to the base material 7 at the same time as the initial point detection command. As soon as (6) touches the point A of the base material G ₁ , the high frequency signal flowing through the base material 7 flows through the torch 6 and the selector switch 5, thereby closing the circuit as shown in FIG. ).

Accordingly, the signal output unit 11 detects a voltage by using a built-in resistor and a rexungx component, and the detected voltage is input to the TTL level generator 12 and compared with a preset reference voltage Vref. A signal such as (bar) is input to the microprocessor 14 of the robot controller 1 through the combiner 13.

At this time, the microprocessor 14 of the robot controller 1 regards the signal as being touched, moves the torch 6 by a distance preset by the program in the y-axis direction, and performs the above operation again. Repeat it.

Here, when the torch 6 is moved and raised in the y-axis direction, the spacing with the base material 7 is set to 2 to 3 mm, and the spacing can be arbitrarily changed.

Therefore, the last to the base (7) when the torch (6) exposed to the C point in the coordinate system of the robot control device (1) Meanwhile, the value of X _3, the current slope of the comparison to the distance of the accumulated X _1, X ₂ of G ₁ Can be easily recognized in the coordinate system. Therefore, if the microprocessor 14 of the robot controller 1 is programmed in advance so that the torch 6 faces the direction of the point D of G ₂ , which is the base material 7, the center point is the point C of G _{1 and} the point D of G ₂ . It is possible to maintain the torch 6 at a certain distance E point by dividing it on the basis of the point.

In addition, in the case of (a, ruler, car) of FIG. 5, if the robot torch 6 is programmed in advance to move in the y-axis direction, the center point to be welded can be found by performing the same method.

At this time, it should be noted that when the torch 6 is first touched by the textbook 7, it is only possible to touch the base material of G ₁ before G ₂ . The reason is that when the base material 7 G ₂ is touched first, the torch 6 of the robot moves a predetermined distance in the y-axis direction and then touches again, so that an error occurs eventually. The base material (7) should be installed so that 6) contacts G ₁ side first.

Therefore, when the torch 6 is located at the point E position by finding the center point of the base material G ₁ and G ₂ , the robot controller 1 may perform the microprocessor 14 as shown in FIG. 4 (a). The welding start command signal is output. The microprocessor 14 then outputs a low level signal through the resistor R ₁ to deactivate the photodiode PD and the photo transistor Q ₁ .

As the transistor Q ₂ is turned off, the relay Ry is inoperative and the selector switch 5 is connected to the connection point Ry so that the oscillation frequency applied through the amplifier 9 and the transformer 10 is cut off. On the other hand, as shown in FIG. 1, a closed circuit (b) in which the welder power source 3 and the torch 6 are connected is formed so that the torch 6 is welded according to the welding shape already stored in the robot controller 1. Will be done.

After the welding operation is completed, the torch 6 returns to its original position by the microprocessor 14 of the robot controller 1 and waits for the next welding operation. The return of the torch 6 to the original position is such that the welding is completed and at the same time, the torch 6 installed on the arm of the robot main body 2 is already set by the command by the microprocessor 14 of the robot controller 1. This is to be placed in position so that the next welding is performed so that the base material 7 is not disturbed when it is transferred to the position set by the transfer balance.

The following describes the initial point detection method of Fillet.

FIG. 6 shows the initial point detection of the horizontal fill (H Fillet), and FIG. 7 shows an example of the vertical fill (V Fillet). During welding of the horizontal and vertical filtrates, the torch 6 has an appropriate inclination according to the angle of the base material G ₁ , G ₂ in order to prevent the overwrapping phenomenon. P ₀ ) is pre-programmed to face G ₁ , the base material (7).

제어라고 말할 수 있으며 그 동작을 좀더 구체적으로 설명하면 다음과 같다.In addition, the movement of the torch 6 by the robot motion is the same as that of the butt, and in particular, the horizontal fillet of FIG.

It can be said that the control and the operation is described in more detail as follows.

First, when the robot control apparatus 1 inputs the initial point detection command signal of FIG. 4 (b) to the microprocessor 14, a high level signal is output through the resistor R ₁ and is selected by the relay Ry. (5) is connected to the connection point Rya.

At this time, the initial point detection device (4) amplifies the 400Hz signal generated by the oscillator (8) through the amplifier (9) and applies it to the transformer (10), the base material 7 To flow).

In this state, the microprocessor 14 of the robot controller ₁ lowers the torch 6 toward G ₁ , which is the base material 7, by a pre-programmed program. The closed circuit (a) is formed at the moment when the torch 6 is moved to and touches G ₁ , which is the base material 7, and the signal output unit 11 detects a voltage by using a built-in resistance and reactance component.

The detected voltage is inputted to the TTL level generator 12 and compared with the preset reference voltage Vref, and is then transferred to the microprocessor 14 of the robot controller 1 through the TTL level optical coupler 13. Input a signal such as

Then, the microprocessor 14 of the robot control board 1 regards the signal as being touched, raises the torch 6 by a predetermined length of X ₁ by a program, and then the direction of the base material G _{2 as} the base material 7. Move to.

Then, the torch 7 comes into contact with the base material 7, G ₂ , and when the touch signal is input to the microprocessor 14 as described above, the torch 6 is moved again by an X ₂ length.

점에 위치하게 되는 것이다.Therefore, the coordinate system of the robot control device 1 is moved by the torch (6) X ₂ length by being thereby position the torch (6) to the point such that the length of X ₁ and X ₂ is that the end position

It will be located at the point.

In addition, in the embodiment of the V fillet of FIG. 7, when the torch 6 first touches the G ₁ surface of the base material 7, as shown in (wave), it is raised by a predetermined distance X ₁ and then G ₂ Direction, and then touch the point B to move the torch 6 to the G ₁ side again.

Therefore, when the torch 6 touches the point C of the G ₁ surface, the length of the C and B points and the angle Q of the G ₁ and G ₂ are calculated to find the center point.

Similarly, the following examples are performed in the same manner.

In this way, the present invention enables the torch to detect the movement distance by the contact signal by moving the torch to the left, right and up and down to the high frequency signal flowing in the base material, thereby accurately finding the starting point, such as the angle and the type of welding Since the welding is performed in response to various conditions, its use is extremely diverse.

Claims (1)

Amplifying the output of the oscillator 8 as an amplifier 9 and applying it to the signal output unit 11 via the transformer 10, the selector switch 5 operated by the microprocessor 14 to the torch 6 ) Can be selectively connected to the signal output unit 11 or the welder power source 3 so that the initial welding start point can be detected or the welder power source 8 can be applied to the toy 6 to perform the welding operation. The output of the signal output unit 11 is input to the microprocessor 14 via the TTL level generator 12, thereby allowing the microprocessor to move the torch 6 up and down and left and right to detect the initial point. Initial point detection device of arc welding robot.

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