KR102004183B1 - Method for welding curved block using distance detection by welding robot - Google Patents

Abstract

A method for welding a work surface of a tune block using a welding robot comprises the steps of: (A) creating a virtual model for a work cell of a tune block and obtaining a tilt angle of the work surface; (B) acquiring an optimal robot base position and moving the robot; And (C) generating an optimum teaching point corresponding to the inclination angle, and checking and correcting the collision situation.
Accordingly, the program is automatically generated based on the welding direction of the flat block orthogonal cell that has been verified in the robot operation of the shipbone groove block welding cell having various angles, and the productivity is greatly improved.

Description

TECHNICAL FIELD [0001] The present invention relates to a method of welding a curved block using a distance measuring method of a welding robot,

More particularly, the present invention relates to a method of welding a groove block using a distance measuring method of a welding robot for realizing a robustness in a shipbuilding field based on a welding robot equipped with a sensor capable of distance measurement .

In the shipbuilding industry, the blocks constituting the ship can be roughly divided into flat blocks and tune blocks. Unlike flat blocks, it is difficult to introduce automation or robotization processes into the block. One of the reasons is that the welding surface has various angles unlike the flat block. In the flat block, if the welding angle is set, it is not modified unless the welding technique is changed. In the case of the curved block, the welding angle should be defined differently according to the slope of the welding surface.

In the case of the current song block, it is common practice to manually perform offline teaching at the OLP stage. However, this method is very inefficient, so all depends on manual welding.

As prior art documents which can be referred to in this connection, Korean Patent Publication No. 2014-0118151 (Prior Art 1) and Korean Patent Registration No. 0671024 (Prior Art 2) are known.

According to the prior art document 1, the welding portions are composed of a preceding torch and a trailing torch arranged side by side at a certain interval from each other, and a weaving motor for driving the preceding torch and the trailing torch respectively to be connected to the preceding torch and the trailing torch, We expect the effect of butt welding of flat and tongue blocks by one welding.

However, this is a structure using a moving wheel and two torches, and shows a limitation in application to a curved block welding in a narrow space, even if it is miniaturized.

The prior art document 2 includes a step of moving the welding robot to a step portion of the workpiece using stored CAD data; Determining and storing three-dimensional position information of the step from a step point of the laser band measured by the laser vision sensor; And performing step welding using the stored information. Thus, an effect of solving the processing time delay and the communication delay of the laser vision sensor is expected.

However, it is difficult to maintain the reliability and durability in the curved block welding, and it requires CAD data, thus it is difficult to increase the speed.

1. Korean Patent Laid-Open Publication No. 2014-0118151 entitled " Welding Apparatus for Ship Evaluation and Tile Blocks "(Open date: October 10, 2014). 2. Korean Patent Registration No. 0671024 "Step Welding Method and System of Welding Robot Using Laser Vision Sensor" (Published Date: Jan. 19, 2007)

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the above-mentioned problems of the prior art by providing a weld robot for efficiently determining the teaching direction of a curved block cell by reflecting a tilting of a welding surface with reference to a teaching direction of a previously- And to provide a method of welding a curved block using a distance measuring method.

In order to achieve the above object, the present invention provides a method for welding a work surface of a tune block using a welding robot, comprising the steps of: (A) creating a virtual model for a work cell of a tune block, ; (B) acquiring an optimal robot base position and moving the robot; And (C) generating an optimum teaching point corresponding to the inclination angle, and checking and correcting the collision situation.

In the detailed construction of the present invention, the step (A) is characterized by obtaining the three-dimensional inclination angles?,?, And? Of the work surface in the virtual model generated by using the distance sensor mounted on the welding robot.

As a detailed configuration of the present invention, the step (B) is characterized by confirming the interference of the torch arm and the reachable motion range of the distance sensor at the current welding robot position.

In the detailed construction of the present invention, the step (C) is characterized in that the direction of the standard teaching point with respect to the origin of the flat block vertical cell is converted into the direction of the optimum teaching point with respect to the curved block working surface.

In this case, in the transformation algorithm of the step (C), the three-dimensional tilt angle of the work surface is input with half values of?,?, And?, Respectively.

In the detailed construction of the present invention, the step (C) is characterized in that the initial position of the standard teaching point on the reference coordinate system is converted into the position of the optimum teaching point for the curved block working surface.

As described above, according to the present invention, the program is automatically generated based on the welding direction of the flat block orthogonal cell that has been verified in the robot operation of the shipbuilding block block welding cell having various angles, and the productivity is greatly improved .

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an exemplary view showing a flat block and a tune block,
Fig. 2 is a schematic view showing the inclination angle of a tune block related to the welding method of the present invention
3 is a process flow diagram illustrating the main steps of a welding method according to the present invention;
Figs. 4 to 7 are diagrams showing details in the main steps of Fig. 3

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention proposes a method of welding a work surface of a tune block using a welding robot. 1 (a) illustrates a tune block of a ship comprising a lower plate 11, a floor 12, a T bar 13, and the like. The T bar 13 has a structure having a flange 16 at the upper end of the longe 15. 1 (a) and 1 (b), the teaching point for the left side flat block is converted into the teaching point for the working surface (U-cell) of the right curved block. Fig. 1 (c) illustrates the state in which the algorithm applied to the method according to the present invention is simulated through a PC screen. The welding robot 20 applies a articulated robot having a wire on the torch arm 22.

The step (A) according to the present invention proceeds to a process of creating a virtual model for the work cell of the tune block and acquiring the tilt angle of the work surface. 4A shows a state in which a virtual model is created and FIG. 4B shows a state in which the welding robot 20 is roughly placed on the T bar 13 (FIG. 4A) State. The virtual model shown in FIG. 4 (a) is generated by various sensors and a known program, and can selectively use CAD information previously designed and stored in the process.

As a detailed configuration of the present invention, the step (A) is characterized by obtaining the three-dimensional tilt angles?,?, And? Of the work surface in the virtual model generated by using the distance sensor 25 mounted on the welding robot 20 . The distance sensor 25 can use any of various known methods and in any case refers to the tip of the wire held in the torch arm 22 as shown. The working plane inclination angles?,?, And? Are obtained using the normal vectors of the lower plate 11, the floor 12, and the longe 15, which are working surfaces of the curved block working cell. The normal vector can be obtained by the three-point measuring method using the distance sensor 25 while moving the torch arm 22 of the welding robot 20. [

The area in which the robot works in the work block cell is a part of the entire curvature portion, so it can be modeled as an inclined surface as shown in FIGS. 2 (a) to 2 (c). The origin (x, y, z) of the reference coordinate system can be set to a point that intersects at the same time with the base plate 11 and the floor 12 of the one side rung 15. α is the angle that the longevity is rotated in the y direction of the origin coordinate, and β and γ are the angles of rotation of the origin coordinates in the x and z directions, respectively. The sign coincides with the coordinate direction.

Referring to FIG. 5A, the inclination angle alpha is obtained in the x-z plane, and the inclination angle beta is obtained in the y-z plane and the inclination angle y is obtained in the z-y plane in reference to FIG. 5 (a), the color of the longe 15 is only an example, and in Fig. 5 (b), the color of the one side longe 15 is expressed by the color superimposed on the lower plate 11 and the longe 15 do.

Step (B) according to the present invention is a process of acquiring an optimal robot base position and moving the robot. Step (B) corresponds to step S40 in FIG. 3 and corrects the position of the welding robot 20 arranged roughly as shown in FIG. 4 (b). 6 illustrates a state in which the base of the welding robot 20 is moved to the left and is disposed at the optimum position.

In the detailed configuration of the present invention, the step (B) is characterized by confirming the interference of the torch arm 22 and the reachable motion range of the distance sensor 25 at the current welding robot 20 position. In order to exclude a state in which the torch arm 22 is interfered with the longe 15 or the like or the maximum expansion of the torch arm 22 and the wire does not reach the work surface at the approximate arrangement of the current position. This algorithm is implemented through a program installed in the welding robot 20, and in this connection, refer to Patent Application No. 2016-0108303 by the present applicant. However, if it is initially determined that the welding robot 20 is disposed at the correct position, the optimum position placement of step (B) may be omitted.

In the step (C) according to the present invention, an optimal teaching point corresponding to the inclination angle is generated, and a collision situation is checked and corrected. Step C corresponds to steps S50 to S70 of FIG. 3, and the optimal teaching point can be outputted on the screen of the PC as shown in FIG. 1 (b) through the algorithm shown in FIG. 7 as shown in FIG. 1 (c). The oblique object of the tile block is modeled and the various inclination angles?,?,? Of the surface to be welded are acquired. Then, the angle and position of the welded teaching point of the flat block of FIG. 1 (a) Apply to block working cell.

In the detailed construction of the present invention, the step (C) is characterized in that the direction of the standard teaching point with respect to the origin of the flat block vertical cell is converted into the direction of the optimum teaching point with respect to the curved block working surface. In Figure 7 (a), ( rpy ) ₀ is the orientation of the reference point relative to the origin in the flat block reference cell (vertical cell or orthogonal cell), and ( rpy ) _t is the direction of the final transformed orientation reflecting the tilting of the block . Through these calculations, yaw, pitch and roll, which are the directional components of the optimal welding teaching point for the origin in the working cell, are generated.

In this case, in the transformation algorithm of the step (C), the three-dimensional tilt angle of the work surface is input with half values of?,?, And?, Respectively. Fig. 2 (d) illustrates a state in which the welding angle to the flat block longeon is reduced in a tune block liner having an inclination at an angle? To the vertical line. As shown in Fig. 2 (e), the welding angle is best when it is half ([theta] / 2) between the inclined slope and the surface to be welded. Therefore, it is preferable to input α / 2, β / 2, γ / 2 in the conversion algorithm of FIG. 7 (a). However, this value can be finally determined through welding test at each teaching point.

In the detailed construction of the present invention, the step (C) is characterized in that the initial position of the standard teaching point on the reference coordinate system is converted into the position of the optimum teaching point for the curved block working surface. (X ₀ , Y ₀ , Z ₀ ) of the reference cell coordinate system to the teaching final position (X _t , Y _t , Z _t ) of the tune block coordinate system using the equation shown in FIG. 7 Conversion. However, since the coordinate basis of this conversion process is the same and there is no positional variation in the vertical direction, Z _t is equal to Z ₀ .

At this time, step (C) of the present invention judges whether a collision occurs (S70), and when a collision occurs, correcting the teaching point information and inputting information (S75) If no collision occurs, the process proceeds to the next step S80. 1 (c), the motion of the welding robot 20 moving the wire of the torch arm 22 onto the teaching point converted as shown in FIG. 1 (b) can be confirmed.

Thereafter, it is checked in step S80 whether there is another work cell, and the work is completed or the process is returned to step S10 and iteratively proceeds.

As described above, the present invention can automatically generate a robot work program of a shipbone tune block welding cell having various angles based on an off-line programming method, thereby greatly improving productivity.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. It is therefore intended that such variations and modifications fall within the scope of the appended claims.

11: Lower plate 12: Floor
13: T Bar 15: Ronji
16: Flange 20: Welding robot
22: Torch arm 25: Distance sensor

Claims (6)

A method of welding a work surface of a tune block using a welding robot, comprising:
(A) a virtual model for a work cell of a tune block, acquires a tilt angle of the work surface, and calculates a three-dimensional (3D) work surface in the virtual model generated using the distance sensor 25 mounted on the welding robot 20. [ Obtaining inclination angles?,?,?;
(B) acquiring a robot base position through movement of the robot by confirming the interference of the torch arm (22) and the range of motion reachable by the distance sensor (25) at the current welding robot (20) position; And
(C) generating a final teaching point calculated by an algorithm set to correspond to the inclination angle, and checking and correcting a collision situation,
Wherein the step (C) transforms the direction of the standard teaching point with respect to the origin of the flat block vertical cell into the direction of the final teaching point with respect to the curved block working surface. . delete delete delete The method according to claim 1,
Wherein the three-dimensional tilt angle of the work surface in the transformation algorithm of the step (C) is input with half values of?,?, And?, Respectively. The method according to claim 1,
Wherein the step (C) converts the initial position of the standard teaching point on the reference coordinate system to the position of the final teaching point on the curved block working surface.

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