JPS61269980A - Control device for weld line following up - Google Patents

Abstract

PURPOSE:To increase a follow-up performance by providing the device outputting hourly the correcting quantity in the height and right and left directions of a torch, by arranging the computing element of respective operation quantity as well as by following up the torch to the weld line according to the operation quantity thereof. CONSTITUTION:An actuator 4 is arranged on a welding torch 3 and an arc sensor 5 is provided as well. Differentiators 8, 12 and computing elements 9, 13 are provided as for processing the signal in the height and right, left directions respectively on the arc sensor 5. The differentiator 8 calculates the difference Iyi of the torch height correction quantity stored in primary and secondary memories 6, 7. The computing elements 9, 13 operate the operation quantity DELTAUy and DELTAUx respectively given by equation (I), equation (II) respectively further. The a1-a4, b1-b4 in the equation are taken as constants. The actuator 4 corrects the position of the torch 3 according to the operation quantity DELTAUy, DELTAUx. The following up performance for the weld line 2 of the torch 3 therefore becomes better.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a welding line tracking control device using fuzzy control.

<Prior Art> The conventional art will be explained using a welding line tracking method using an arc sensor as an example.

Fig. 3 shows an overview of the conventional technology, in which 01 is the object to be welded, 02 is the welding line, 03 is the welding torch, 04 is the actuator that performs oscillation operation, torch height tracking operation, and welding line tracking operation, and 05 is an arc sensor. The welding torch 03 is supplied with power and wire from a welding power source and a wire feeding device (not shown in the figure), and generates an arc between it and the workpiece O1 to perform welding, but at the same time, the actuator 04 Welding is performed by moving in the direction of welding line 02 using a traveling truck, manipulator, etc. not shown in .

However, if the welding line 02 draws an irregular curve as shown in the figure, the welding torch 03 will deviate from the welding line 02, so the arc sensor 05 will be required.

Arc sensor 05 detects the amount of deviation of the welding torch from the groove center line by comparing the welding current and the welding tip-to-base metal distance changes caused by the groove shape on the left and right sides of the simulation. It is widely used in welding robots and other applications. Therefore, by inputting the electric current, voltage V, wire feeding speed V, etc. from the power source wire feeding system including the welding torch 03 to the arc sensor 05, and at the same time inputting the oscillation information θ from the actuator 04, the deviation of the welding torch 03 will be controlled moment by moment. Determine the amount and adjust the torch height correction amount Δ
Since Y and the horizontal correction amount ΔX are output to the actuator 04, the welding torch follows along the welding line 02, and welding is completed.

(Problems to be solved by the invention) The welding atmosphere is a harsh environment with high temperatures, exposure to strong light, fumes, and spatter, and strong electromagnetic disturbances.For this reason, it is difficult to follow the weld line. The output of the sensor used includes noise components.Therefore, if the correction signal from the sensor is fed back to the actuator as is, the trajectory of the welding torch is likely to cause hunting as shown in Figure 4.To prevent this, the sensitivity must be lowered. As a result, the range of application was limited and welding defects were induced, which was a serious problem in practice.

(Means for solving the problems) The present invention aims to solve the problems of the above-mentioned prior art by using ambiguous control,
The configuration of the welding line tracking control device of the present invention that achieves this object includes a correction amount output device that momentarily outputs the torch height correction amount ΔYi and the torch lateral direction correction amount ΔXi, and a primary storage device that stores the torch height correction amount ΔYj. A memory, a secondary memory that stores the correction amount ΔYi−1 a certain time ago, and a difference numerator, i(
−ΔYi−ΔYi−1), a primary memory that stores the rightward correction amount ΔXi, a secondary memory that stores the correction amount Δxi−1 from a certain time ago, and a difference Ixi(−
ΔXi−ΔX1−1), and ΔUY, Δ
The present invention is characterized by comprising an actuator that causes the welding torch to follow the welding line according to the UX.

<Operation> In the present invention, since the amount of correction and the difference thereof are each processed by a membership function to determine the amount of operation, it is possible to smoothly follow the weld line even with a correction signal with many noise components.

<Example> FIG. 1 shows an example in which the present invention is applied to an arc sensor.

In FIG. 1, l is the object to be welded, 2 is the welding line, 3 is the welding torch, 4 is the actuator, and 5 is the arc sensor.The welding procedure, arc sensing means, etc. are completely the same as in the conventional method.

Next, 6 to 9 are processing circuits for torch height correction signals, 6 is a primary memory, 7 is a secondary memory, 8 is a subtractor, and 9 is an arithmetic unit. Further, 10 to 13 are processing circuits for left/right correction signals, 10 is a primary memory, and l! is secondary memory, 1
2 is a difference device, and 13 is an arithmetic unit.

To explain these effects, the torch height correction amount ΔYi and the horizontal correction amount ΔXi outputted from the arc sensor 5 are inputted moment by moment to the memory 6 and IO using the same means as in the conventional method, and at this time, the torch height correction amount ΔYi and the horizontal correction amount ΔXi are input to the memory 6 and IO. Stored correction amount Δyi−tl
Δxi-t are shifted to secondary memories 7 and 11, respectively. Therefore, the differentiator 8 calculates the difference Iyi between the torch height correction amounts stored in the primary memory 6 and the secondary memory 7 according to the following equation.

Iyi=ΔYi−ΔYi−1 Further, the differentiator 12 calculates the difference 1xi between the correction amounts in the left and right direction stored in the primary memory 10 and the secondary memory 11 according to the following formula: ■・=ΔX・−ΔX1−1! 11 Next, the calculator 9 calculates the operation amount ΔU of the torch height from ΔYi stored in the primary memory 6 and the difference device yi calculated by the difference device 8 according to the following equation.

jan-'(a2·I,,)>The computing unit 13 computes the left-right direction operation amount Δux from ΔXi stored in the primary memory 10 and the difference Ixi computed by the difference unit 12 according to the following equation.

jan-' (a441H) ) also al・a2・a3・a4・bl・b2・b3・b4
is a constant and is stored in the memory in the computing unit 9 or 13 and called up at any time to be used for computation.

Operation amount Δuy from computing units 9 and 13; ΔU! is input to the actuator 4, and the position of the welding torch 3 is corrected accordingly.

In the above embodiment, the arc sensor 5 is used as the correction amount output device, but other stylus sensors, electromagnetic sensors, visual sensors, etc. may be used, and the torch height correction output from these may be used. Ambiguous control may be performed based on the amount ΔYi and the torch lateral direction correction amount ΔXi.Furthermore, the present invention can be applied to an automatic guided vehicle, etc. that moves without detecting the guide set by various sensors. It is.

<Effects of the Invention> As described above in detail based on the embodiments, the welding line tracking control device of the present invention utilizes ambiguity control and can obtain a smooth signal from a modified signal with many noise components. Therefore, as is clear from Figure 2, which shows the results of measuring the torch trajectory following a sinusoidal welding line using a displacement meter, the tracking performance is significantly improved compared to the conventional method (Figure 4). can be improved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram showing a torch trajectory according to the present invention, FIG. 3 is a block diagram of a conventional control device, and FIG. 4 is based on the prior art. It is an explanatory view showing such a torch locus. Inside the drawing. l is the object to be welded, 2 is the welding line, 3 is the welding torch, 4 is the actuator, 5 is the arc sensor, 6.10 is the primary memory, 7.11 is the secondary memory, 8.12 is the differentiator, 9.13 is an arithmetic unit.

Claims (1)

[Claims] Torch height correction amount ΔY_i and torch horizontal direction correction amount Δ
A correction amount output device that outputs X_i every moment, a primary memory that stores the torch height correction amount ΔY_i, a secondary memory that stores the correction amount ΔY_i_-1 a certain time ago, and a difference I_
A differentiator that calculates y_i (=ΔY_i−ΔY_i_−_1) and an operation amount ΔU_y(=[2b_1b_2/π(b
_1+b_2)] {tan^-^1(a_1・ΔY_i
)+tan^-^1(a_2・I_y_i)}), a primary memory that stores the torch horizontal direction correction amount ΔX_i, and a correction amount ΔX_i_-_1 a certain period of time ago.
and the secondary memory that stores the difference I_x_i (=ΔX_i
-ΔX_i_-_1), and a manipulated variable ΔU_x(=[-2b_3b_4/π(b_3+b_4
)] {tan^-^1(a_3・ΔX_i)+tan^
-^1(a_4·I_x_i)}); and an actuator that causes a welding torch to follow the welding line in accordance with the manipulated variables ΔU_y and ΔU_x.