JPH08215844A - Multi-layer welding equipment - Google Patents

Abstract

PURPOSE: To simultaneously make torch position optimum in generating return track of multi-layer welding. CONSTITUTION: Multi-layer welding equipment has functions which teaches a first pass and its torch position being the track connecting a series of teaching points from welding start to completion, automatically generates the remaining pass based on the above with executing shift operation of specified quantity only and automatically generates the pass so as to make plurally numbered pass to return track. Further, the means to control welding is provided so that the torch position in return pass is made facial symmetry to the torch position in welding of the first pass taught beforehand against the plane vertical to weld line connecting adjacent two points. By this method, the teaching work efficiency at multi-layer welding is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-layer welding (multi-layer welding) device using a welding robot.

[0002]

2. Description of the Related Art Conventionally, in the case of multi-layer welding, only the teaching of the first pass is performed, and the remaining passes store the locus of the first pass or the position of the locus corrected by the tracing control of the first pass such as arc sensing. A device that automatically generates the traces of the second and subsequent passes by scaling up and down by a specified amount based on the traced traces (hereinafter referred to as the sampling pass traces), or an even trace (an odd trace that is an odd-numbered welding). Is the forward welding from the start point to the end point, and the even-numbered trajectory, which is the even-numbered welding, is the retrograde welding from the end point to the start point) is automatically performed for the first pass or sampling pass trajectory. A device for making a return path is used (see FIG. 2). In either case, when the return path is automatically generated, the order of the position data of the base trajectory is simply reversed.

[0003]

When welding is performed by an industrial robot, it is often the case that the moving angle of the torch posture is slightly advanced. In the case of the return path automatic generation function in the conventional method, it is realized only by generating the reverse trajectory by reversing the order of the movement commands and the trajectory shift processing, so the movement angle is taught by the forward angle. As a result, the position became a receding angle (since the welding direction was reversed), and the posture was unsuitable for welding. For this reason, when the first pass is taught, the movement angle is made perpendicular to the welding line, or the return pass is automatically generated and the posture is taught again. Was there.
Therefore, it is an object of the present invention to provide a device capable of simultaneously adjusting the torch posture to an optimum posture when generating a return trajectory.

[0004]

In order to solve the problems, the present invention teaches a first pass, which is a locus connecting a series of teaching points from the start to the end of welding, and a torch posture at that time,
In the multi-layer welding device having the function of automatically generating the remaining paths based on the shift operation by the designated amount and automatically generating the paths so that the even paths become the return loci, Welding control is performed so that the torch posture of the path is plane-symmetric with the torch posture of the first pass, which is taught in advance, with respect to the plane perpendicular to the welding line connecting the two adjacent teaching points. It is characterized in that a means for doing so is provided.

[0005]

As a result, when the movement angle of the torch posture 1 of the first pass is taught as the forward angle, the torch posture 2 of the return pass is automatically moved forward with the same movement angle of the torch posture with respect to the welding line as the first pass. It becomes a corner, and it becomes unnecessary to change the teaching of the posture after the automatic generation of the return path which is conventionally required (see FIG. 1).
FIG. 1B is a view seen from the direction B in FIG.

[0006]

EXAMPLE A specific example will be described below (calculation processing flow is shown in FIG. 5). When P1 to Pn are present as teaching points on the welding locus in the return path operation program that is generated so as to have an inverse locus with respect to the first pass, the following calculation is performed to find Pn 'to Pn'. , Teaching position Pn ~ P
replace n.

When P1 to Pn exist as teaching points on the welding locus, the orthogonal positions of P _i and P _{i + 1} (i is 1 to n-1) in the robot coordinate system are Pi (Xi, Yi, Zi). And Pi + 1 (Xi + 1,
Yi + 1, Zi + 1).

A welding line direction unit vector (L) is obtained from orthogonal data of two adjacent points (Pi, Pi + 1). D = √ {(Xi + 1- Xi) ² + (Yi + 1- Yi) ² + (Zi + 1-
Zi) ² } Lx = (Xi + 1− Xi) / D Ly = (Yi + 1− Yi) / D Lz = (Zi + 1− Zi) / D

Of the two points, the taught posture data of the point (Pi) with respect to the plane (H) including the point (Pi) from the operation start point and perpendicular to the welding line direction unit vector (L). (N: Normal vector, O: Orient vector, A: Approach vector)
Torch direction unit vector (A: approach vector)
Then, a unit vector (A ′) which is plane-symmetric with is obtained (see FIG. 3).

-1) Let M be the outer product of L and A. M = L × A −2) Let N be the cross product of L and M. N = L × M −3) The unit vector (L, M, N) obtained above is used as the transformation T.

[0011]

[Equation 1]

-4) When the unit vector A is a vector (At) viewed from T, At = T ^-1 * A (At = [Atx Aty Atz]) -5) Symmetric vector At '
Becomes At '= [-Atx Aty Atz] -6) Convert At' into the robot coordinate system and set it as A '. A ′ = T * At ′ Attitude data (N ′, O ′) obtained by rotating the remaining attitude data (N, O) of the teaching point Pi about the unit vector (M) by the angle (θ) formed by A and A ′. ) Is calculated by the following calculation (see FIG. 4). -1) θ = cos-1 (AxA'x + AyA'y + AzA'Z) -2) Versθ = 1-cos θ -3)

[0013]

[Equation 2]

N ′ obtained by the above calculation,
Replace O'and A'with the attitude of the new teaching position. Repeat up to i = 1 to N-1. For the last point Pn, the welding vector unit vector in the section of Pn-1 to Pn is set to L and the calculation of is performed. As described above, the movement angle of the torch posture of the return path becomes the same as the forward angle of the first path, and the return path automatic generation, which is conventionally required, becomes unnecessary.

[0015]

As described above, according to the present invention, the torch posture of the return pass automatically takes the same movement angle with respect to the welding line direction as the first pass, and the teaching correction of the return pass posture is performed. Is unnecessary, the teaching work efficiency in multi-layer welding is significantly improved.

[Brief description of drawings]

FIG. 1 is an explanatory view of the operation of the present invention, in which (a) is a perspective view,
(B) is the figure seen from the B direction of (a).

FIG. 2 is a diagram showing paths in multi-layer welding.

FIG. 3 is a diagram for explaining calculation of A ′.

FIG. 4 is a diagram for explaining calculation of N ′ and O ′.

FIG. 5 is a flowchart showing a calculation processing procedure.

[Explanation of symbols]

 1 Teaching attitude of the first pass 2 Teaching attitude calculated and obtained by the present invention

Claims (1)

[Claims] 1. A first path, which is a locus connecting a series of teaching points from the start to the end of welding, and a torch posture at that time are taught, and the remaining paths are shifted based on the first path by a designated amount. In a multi-layer welding device having a function of automatically generating by applying the path and automatically generating even paths so as to automatically return paths, a torch posture of the returning path is obtained by connecting two adjacent teaching points. A multi-layer welding apparatus comprising means for controlling welding so as to be plane-symmetric with respect to a torch posture at the time of welding of the first pass, which is taught in advance, with respect to a plane perpendicular to the welding line.