KR20080111977A - Automatic multi-wire welding system with wireless communication and seam tracking functions - Google Patents

Abstract

An automatic multi-wire welding system capable of wireless telecommunication and welding seam tracking is provided to increase productivity by mounting two wires on one torch. An automatic multi-wire welding system capable of wireless telecommunication and welding seam tracking comprises a wireless remote pendant(1), a welding carriage(2) including a system capable of feeding two wires to one torch, a wireless database system(3) transmitting a database wirelessly, a main control system(4) which transmits and receives wireless data and sends the data to different control boards so that each control board performs the operation corresponding to the data, a personal mobile terminal(5) transmitting the database, a wire feeder box(6) configured to feed two wires to one torch, and a welding machine(7) performing the wire feeder and welding.

Description

Automatic multi-wire welding system with wireless communication and seam tracking functions}

1 is a view showing a multi-electrode automatic welding system capable of wireless communication and welding seam tracking of the present invention.

2 is a view showing the operation of the wireless remote pendant of the present invention.

3 is a diagram showing the characteristics of the welding signal of the present invention.

4 graphically depicts a weld seam tracking algorithm of the present invention.

5 illustrates a multi-electrode welding system of the present invention.

Conventional onshore and offshore pipe welding has a problem in that its characteristics must be connected to the pipes by direct welding at the site where it is intended to be installed. In the case of large pipes, welding can be performed while the pipe is rotated under a fixed torch, but it is not only difficult to fix the welding torch in the field, but also installation of equipment for rotating a heavy pipe roll is a problem. Can be.

In order to solve this problem, an orbital we1ding carriage, which can weld a fixed pipe while the welding carriage rotates, has been developed, but most of them are over 500kg in size and weight. Therefore, it is very difficult for workers to move easily in the actual site, and there is a problem in that a heavy weight welding carriage must be moved in order to weld at a desired welding position.

Recently, in order to solve these problems, orbital welding carriages that can be easily welded by workers have been developed or developed in various forms abroad. And gas tungsten arc welding. Prior to the development of digital automatic welding carriages, analog carriage controllers were the mainstay, and tended to be affected by poor welding environment and ambient temperature. In the case of digital controllers, the speed of development is increasing very rapidly in recent years, and most of the recently developed welding carriage controllers have exhibited products using digital characteristics.

The welding carriage controller with digital function is not only affected by the bad environment and ambient temperature, but also the motor control, welding machine control, oscillation control, and welding conditions stored in the database. By using the function that can be controlled by the control and the pre-programmed function, the function can be used efficiently. Products and patents developed overseas have various functions such as automatic welding condition control, oscillation control, welder control, and real real time control is also successfully implemented. However, these products consist of only one wire per torch and all functions are controlled by the remote's remote pendant. In addition, in order to track the weld, the operator directly tracks the welding line through the remote pendant. In particular, when the wired remote pendant is used in a harsh working environment, the wired cable may be damaged by the surrounding environment, making it unusable.

The present invention devised to solve the above problems is to change the wired remote pendant to wireless, to automatically implement the welding seam tracking manually, and to increase the output by mounting two wires in one torch An object of the present invention is to provide a multi-electrode automatic welding system capable of wireless communication and welding seam tracking.

The present invention for achieving the above object, a wireless remote pendant; A welding carriage having a system capable of feeding two wires to one torch; A wireless database system capable of transmitting a database wirelessly; A main control system configured to transmit and receive wireless data and transmit the received data to various control boards so that individual control boards perform an operation corresponding thereto; A personal terminal capable of transmitting a database; A wire feeder box configured to feed two wires to one torch; And it provides a multi-electrode automatic welding system capable of wireless communication and weld line tracking including a wire feeder and a welder for performing the welding.

Preferably, the multi-electrode automatic welding system capable of wireless communication and seam tracking may use an arc sensor algorithm based on a moving average algorithm.

More preferably, the moving average algorithm, Value _mean (k) _{k = 1-100} = {Value _forward (k) + Value _backward (k)} / 2 can satisfy the above equation.

In order to fully understand the present invention, the advantages of the operability of the present invention, and the objects achieved by the practice of the present invention, reference should be made to the accompanying drawings which illustrate preferred embodiments of the present invention and the contents described in the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals in the drawings denote like elements.

Multi-electrode automatic welding system capable of wireless communication and welding seam tracking of the present invention is large, wireless remote pendant, welding seam tracking sensor, multi-electrode welding torch, welding machine control and welding condition control system, motion control system for oscillation, welding speed setting It consists of a motion control system for the system, a main control system for database access, and a database system for managing each board as a whole.

The driving process of the system is a process in which arbitrary functions are transmitted to the main control system through the wireless remote pendant operation, a process of transferring any data transmitted to each control system via the main control system by wire, and each It can be divided into a process in which the control system performs a function independently using the transmitted data.

1 is a view showing a multi-electrode automatic welding system capable of wireless communication and welding seam tracking of the present invention.

Referring to FIG. 1, a multi-electrode automatic welding system capable of wireless communication and welding seam tracking includes a wireless remote pendant 1, a welding carriage 2 having a system capable of supplying two wires to one torch, and a wireless ( Wireless database system (3) capable of transmitting a database over a wireless ethernet, and a main control system (4) configured to transmit and receive wireless data and to transmit data to various control boards so that individual control boards perform an operation according thereto. A personal terminal (PDA) 5 capable of transmitting a database, a wire feeder box 6 configured to feed two wires to one torch, and a welder 7 for performing the wire feeder and welding.

2 is a view showing the operation of the wireless remote pendant of the present invention.

Referring to FIG. 2, when the function switch 14 of the wireless remote pendant 1 is pressed, the function of the selected switch is displayed on the LCD 15, and data related to the function is transmitted and transmitted through the antenna 13. (S21), a process of displaying on the LED 12 whether the transmitted data is normally transmitted, the process of receiving the data transmitted through the antenna 18, the main control system 4 and the LED 16 whether the reception was made normally And displaying the received data on the touch screen 20 mounted on the main control system.

When the reception is normal, the main control system 4 sends the received data back to the wireless remote pendant through the wireless antenna 18 in order to check whether the wireless remote pendant is normally transmitted and received (S22). When the received data is not received from the system, the wireless remote pendant 1 is configured to transmit data again after a certain time (S23).

On the other hand, the sensor for implementing seam tracking can be divided into laser vision sensor, contact sensor and arc sensor. The dual laser vision sensor has a disadvantage that the price is expensive and the contact sensor has a problem of low durability.

On the other hand, the arc sensor uses a change in current and voltage in accordance with the characteristics of the welder as the tip-to-workpiece distance changes. Gas Meta1 Arc We1ding (GMAW) using consumable electrodes can be classified into constant vo1tage and constant current according to the welder power supply characteristics. In the case of the constant voltage, the welding current decreases as the tip-to-base distance increases, and the welding current increases as the shortening becomes short. At this time, the voltage is kept almost constant. In the case of a constant current welder, the current is constant as the tip-to-base distance increases, but the physical property of the voltage decreases as the voltage increases and shortens.

3 is a view showing the characteristics of the welding signal of the present invention.

Referring to FIG. 3, reference numeral 101 shows the characteristics of the constant voltage and constant current welding machine, and reference numeral 102 shows the change of the voltage and current signals according to the change of the torch distance. Using this principle, the welding torch measures the welding current or welding voltage value in the weaving state as it moves between the two ends of the weld, and compares it with the reference current (or voltage) and the current (or voltage) value of the previous stage. It will change the weaving direction of. However, when measuring the current value (or voltage value) according to the distance between the electrode and the base material, these values change significantly due to the metal transition mode, and the reliability of these measured values decreases due to electrical noise, which in turn lowers the accuracy of the arc sensor. It becomes a factor.

The arc sensor algorithms developed so far have been used to determine the voltage value (or current value) near the end of the groove using a moving average (integral method) and curve fitting. fitting). The method of determining the voltage value of the end by using the moving average value near both ends may lose its function as an arc sensor if the algorithm implementation method is not only reliable but also noise influenced by the characteristics of the processor. The curve fitting method is more reliable in determining the end voltage value, but it may be a problem because it tends to follow the noise interference.

In the case of curve fitting, the reliability is high, but generally the welding signal such as the V-groove is generally reliable when predicted in the form of two-dimensional curve by the welding pool, but the groove is narrow like the subsea pipeline and the measured signal at the weaving end is In the case of rapidly rising or falling, there is a problem that it is very difficult to apply.

When using the moving average algorithm to implement the arc sensor, there is a problem in that the characteristics of the measured signal are accurately analyzed and various constraints are introduced. The present invention provides an arc sensor algorithm based on a moving average algorithm rather than a curve fitting method to develop an arc sensor that can be applied to both narrow welds as well as general welding improvements.

One of the prevailing conditions for arc sensor implementation is how reliable can be in the voltage / current values measured when the torch weaves along the groove. As a result of welding experiment, both voltage and current showed the same signal characteristics according to the tip-base distance, and the rate of change of the voltage or current value according to the change of the tip-base distance has a proportional relationship.

When measuring the voltage or current signal during actual welding to find the tip-base distance, the current signal contains various noises and also includes electrical noise depending on the transfer method of molten metal when the wire melts and falls during welding. Converting the tip-to-substrate distance immediately from the weld voltage value risks generating an error.

In the present invention, analog-to-digital conversion of the measured voltage or current signal through a low pass filter (1ow pass fi1ter) is performed in hardware, and a digital filter effect is added to the converted voltage signal by a moving average algorithm. The voltage signal thus processed should immediately form a groove shape under the torch, but in reality it is difficult to determine exactly how far the torch is from the groove center point, including the characteristics of the processor such as voltage noise components and arc instability. Therefore, if the shape of the groove is assumed and the pattern of the voltage or current value during the weaving can be predicted, this difficulty can be greatly reduced. Based on the above, the present invention performs welding seam tracking by specifying various variables for moving averaged values.

The measured welding voltage signal correlates with the previous value to increase the reliability of the data, and a simple algorithm for this is the moving average. The signal measured using the moving average undergoes a digital filtering effect, which improves the reliability of the measured signal and stabilizes the control signal more. The moving average may be expressed as Equation 1 below.

Here, value _a (k) is the average value at k step, value _a (k-1) is the average value at k-1 step, value _m (k) is the measured signal value at k step, and factor is the moving average factor. Means.

The moving average method represented by Equation 1 is very simple and easy to implement, but has one problem. The moving averaged signals may have an effect such as a kind of phase angle change. If the previously averaged values are low, there is a problem in that the values are smaller by the previous moving average value even if the measured value is higher. For example, there is a slight signal difference between values processed by moving average from the left side of the measured signal during weaving and values averaged on the right side. That is, the moving average value based on the measured signal left and the moving average value based on the right show different characteristics.

4 is a graph illustrating a weld seam tracking algorithm of the present invention.

Referring to FIG. 4, the characteristic between the moving average value based on the left side, the moving average value based on the right side, and the value averaged again from the moving average value on the left side is clearly shown. The "Forward moving average signal" signal at 202 starts by reflecting the high voltage value of the initial left, and the "Backward moving average signal" signal at 203 is actually measured because all values are reflected based on the signal on the right. The pattern of the signal 201 shows a lot of difference.

Because of this principle, in the case of an arc sensor using a moving average in one direction, unexpected tracking results can be obtained. As can be seen in Figure 4 "Forward moving average signa1" (202) (Formula: value _forward (k) _{k = 1 ~ 100} = {(factor-1) * value _a (k-1) + value _m (k) } / factor) and "Backward moving average signa1" (203) (expression: Value _backward (k) _{k = 100 ~ 1} = {(factor-1) * value _a (k) + value _m (k-1)} / factor) The actual measurement of "Mean moving average signal" (204) averaging both values (Equation: Value _mean (k) _{k = 1 to 100} = (Value _forward (k) + Value _backward (k)} / 2) It is the best representation of the pattern of the signal, and it also shows the characteristic of filtering the variable signal values. In the present invention, the arc sensor is implemented using a method of averaging moving averaged data from the left and the right.

5 is a diagram illustrating a multi-electrode welding system of the present invention.

Referring to FIG. 5, a general pipe welding system includes a system in which one wire is supplied to one torch. However, the present invention provides a multi-electrode welding system in which two welding wires 305 are mounted on one torch 303 as shown in FIG. 5. Welding is supplied from the welder 301 through the wire feeder box 302 to the welding torch 303 by the welding wire 305 and the supplied welding wire forms an arc on the pipe 304 surface.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. . Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

The present invention changes the wired remote pendant to wireless, automatically implements the welding seam tracking that is being worked manually, and enables the wireless communication and the seam tracking to increase the yield by mounting two wires in one torch. Provides an electrode automatic welding system.

Claims (3)

Wireless remote pendant; A welding carriage having a system capable of feeding two wires to one torch; A wireless database system capable of transmitting a database wirelessly; A main control system configured to transmit and receive wireless data and transmit the received data to various control boards so that individual control boards perform an operation corresponding thereto; A personal terminal capable of transmitting a database; A wire feeder box configured to feed two wires to one torch; And A multi-electrode automated welding system capable of wireless communication and weld line tracking including wire feeders and welders for performing welding. The method of claim 1, The multi-electrode automatic welding system capable of wireless communication and welding seam tracking is a multi-electrode automatic welding system capable of wireless communication and welding seam tracking using an arc sensor algorithm based on a moving average algorithm. The method of claim 2, The moving average algorithm, Value _mean (k) _{k = 1 ~ 100} = {Value _forward (k) + Value _backward (k)} / 2 Multi-electrode automatic welding system capable of wireless communication and welding seam tracking that satisfies the above formula.

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