JPH02205266A - Detection of groove route gap by memory and reproduction type arc welding robot - Google Patents

Abstract

PURPOSE:To detect the subject gap with the accuracy which does not hinder welding in the subject method using the robot having a sensing means for detecting the positions of members even if there is an errors in groove angle by executing specific steps. CONSTITUTION:A torch 8 which supports a welding wire 8a of a prescribed projecting length is moved in, for instance, the transverse direction X of a single Vee groove and the positions P1, P2 of groove faces 9a, 9b facing each other are detected by the sensing means. The equal position P3 in the direction X is determined by computation from the data on these positions. The torch is then moved from the position P3 in the direction of the base 10 of the groove route and after the base 10 is detected, the torch is turned back by a prescribed distance L and the front end of the wire 8a is positioned near the base 10. The torch is again moved in the direction X from this position and to positions P4, P5 of the groove faces 9a, 9b are detected. The groove route positions Q1, Q2 are determined by computation from the position data, the distance L and the inputted groove angles theta1, theta2 and the distance between both is computed and determined as the groove route gap.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention applies a sensing voltage between a torch that supports a welding wire (hereinafter referred to as wire) and a workpiece in a memory/replay type arc welding robot. The present invention also relates to a groove gap detection method using a memory/regeneration type arc welding robot, which detects the groove root gap using a sensing means that detects the energization state due to contact between the wire and the workpiece and detects the position of the workpiece. It is something.

[Prior Art] In general, a workpiece (object to be welded) composed of a member having a plate thickness of approximately 5 am or more has a groove root gap.
Welded joints with butt grooves, such as shapes and shapes, are used. However, the groove root gap of these welded joints usually varies from the design value due to processing accuracy and assembly errors of the members forming the welded joint.

When such welding joints are automatically welded by a memorization/regeneration type arc welding robot, the groove root gap is detected before welding starts, and the welding method taught in advance is performed according to the value of the detected groove root gap. Among the conditions, it is necessary to change the weaving width, welding speed, etc. Therefore,
The applicant has previously proposed a method for detecting groove gears and knobs for automatic welding equipment, in which a sensing voltage is applied to a torch that supports the wire, and this torch is used as a sensor to detect the groove root gap. (Special application 1986-240)
No. 719).

Hereinafter, using a V-shaped groove as a specific example, this conventional groove root gap detection method will be explained using the explanatory diagram of the teaching operation according to the conventional method shown in FIG. 7 and the explanatory diagram of the conventional method shown in FIG. I will explain while referring to it. Torch (8) as shown in Figure 7
The protruding length of the wire (8a) from the wire (8a) is set to a predetermined length, and the first welded joint is first taught to perform sensing, which will be described later, in the following steps.

■ After teaching the sensing start point PS1 near the member surface Ac of the first member Aa, lower the torch (8) and bring the tip of the wire (8a) into contact with the member surface Ac to teach the teaching point PIT. . Similarly, a sensing start point PS2 near the member surface Ac and a teaching point P2T on the member surface Ac are taught.

■ Next, a sensing start point PS3 is taught near the groove surface Ad of the first member ^a, the torch (8) is lowered to teach a teaching point P3T on this groove surface Ad, and similarly, 1st
A sensing start point PS4 is located near the groove surface Af of the second member Ab opposite to the groove surface Ad of the member Aa, and a light surface A
A teaching point P4T is taught on f.

After performing such teaching work in advance, the groove root gap in subsequent workpieces is detected by the following procedure (see FIG. 8).

Here, a sensing voltage is applied to the torch (8) to move it, and a wire (
8a) and members Aa and ^b forming the welded joint to detect the energized state and detect the position of the members is called sensing.

■ First, a sensing voltage is applied to the torch (8) positioned at the sensing starting point PS1, and this starting point Psi
The torch (8) is moved in the direction from to the teaching point PIT, a point P1 on the member surface Ac of the first member ^a is detected by sensing, and the position information of this point PI is stored.Similarly, The torch (8) is moved in a direction from the sensing start point PS2 toward the teaching point P2T, and the point P2 on the member surface Ac of the first member ^a is detected by sensing, and the position information thereof is stored.

■Next, sensing is performed in the direction from the sensing starting point PS3 toward the teaching point P3T, and the point P3 on the groove surface Ad of the first member ^a is detected and this positional information is memorized. Sensing is performed in the direction from the starting point PS4 to the teaching point P4T, and the groove surface A of the second member AbO is
4 and stores this position information.

■ After obtaining these location information, first, check the above two points P.
Based on the position information of I and P2 and the plate thickness dimension of the first member Aa input in advance, as shown in FIG.
Points Pi' and P2° are determined, and a gap position straight line L1 along the back surface of the member surface Ac passing through these points is calculated and determined.

■ Next, the first member Aa is opened along the groove surface Ad based on the position information of the point P3 on the groove surface Ad and the groove angle θyo of the first member Aa that has been input in advance. In addition to calculating and finding the tip straight line L2, the opening of the second member Ab is calculated based on the position information of the point P4 on the groove surface Af of the second member Ab and the groove angle θ of this member ^b that has been input in advance. A groove straight line L3 along the front surface Af is calculated and determined.

■ Then, the above gap position straight line Ll and the first member ^
The intersection Bl of the groove line L2 of the second member Ab is calculated as the root position of the first member Aa, and the intersection B2 of the gap position line L1 and the groove straight line L3 of the second member Ab is calculated as the root position of the first member Aa.
Calculate and find the root position of.

In the conventional groove root gap detection method, the root position Bl of the first member Aa and the second member Ab are determined by such a procedure.
The route position B2 is determined, and the determined route position B1.8
The groove root gap is detected by calculating the distance between the two.

[Problem to be solved by the invention]

However, there are differences in machining accuracy, etc. between the groove angles θ and θ4 of both members Aa and Ab that are input in advance, that is, the designed groove angle and the actual groove angle for each workpiece. Because errors often occur due to
The conventional method introduced above has the following problems.

First, to explain the case of determining the root position B1 of the first member Aa, the detection point P3 on the groove surface Ad of the first member AaO is sensed in a predetermined direction by the teaching operation as described above. This is the position detected by. Therefore, since there is a mounting error between the first workpiece on which the teaching operation was performed and the subsequent workpieces, the position of the detection point P3 on the groove surface Ad differs for each workpiece.

Therefore, the position of detection point P3 is close to the root position to be determined (in some cases, even if there is an error between the groove angle θ8 of the first member Aa input in advance and the actual groove angle, The calculated root position, which is calculated as the intersection of the groove straight line L2 along the plane Ad and the gear position straight line ILI, can be determined with respect to the actual root position with an accuracy that does not interfere with welding. If the position of the detection point P3 is located away from the desired root position along the groove surface Ad in the direction of the member surface Ac, there is an error between the actual root position and the calculated root position. There is a problem that arises.

Also, when determining the root position 1 of the second member Ab, there are problems similar to those described above.

Therefore, in the conventional method, when the position on the groove surface detected by sensing is not close to the desired root position but is far away, the accuracy of the detected groove root gap deteriorates. There was a problem.

Therefore, the present invention has been made to solve these problems, and it uses the groove angle of the groove surface that is input in advance and the actual groove of each workpiece to be used for detecting the groove root gap. Provided is a groove root gap detection method using a memorization/regeneration type arc welding robot that can detect the groove root gap with accuracy that does not hinder welding even when there is an error between the angle and the processing accuracy due to processing accuracy, etc. With the goal.

[Means to solve the problem]

In order to achieve the above object, the method according to the invention comprises:
Equipped with a sensing means that applies a sensing voltage between a torch that supports a welding wire set to a predetermined protrusion length and the workpiece, detects an energized state due to contact between the welding wire and the workpiece, and detects the position of the workpiece. The memory/regeneration type arc welding robot detects the groove root gap of the groove formed by the opposing groove surfaces and the groove root bottom.The groove root gap is detected by the memory/regeneration type arc welding robot. In the detection method, each of the following steps, i.e. (=i) moving the torch in the groove width direction of the groove, detecting the position of each of the opposing groove surfaces by the sensing means, and obtaining the position data. (b) Calculate and find equal division positions in the groove width direction from this double groove surface position 1 data; (c) Move the torch from this groove width equal division position in the direction of the bottom surface of the groove root. ,
After detecting the bottom surface of the groove root by the sensing means, the torch is pulled back a predetermined distance to position the welding wire tip near the bottom surface of the groove root; (d) from this pulled back position again in the groove width direction; (e.
) Opposing groove surfaces based on the position data of both groove surfaces obtained in step (d) above, the pullback distance in step (c) above, and the groove angle of the opposing groove surfaces input in advance. calculating and finding the groove root position of each of the grooves;
(f) The distance between both groove root positions is calculated and detected as a groove root gap.

[For production]

The torch is moved in the groove width direction, and the position of each of the opposing groove surfaces is detected by the sensing means. From this detected position data of both groove surface positions, the groove width equal dividing position located at the center of both groove surface positions is calculated by calculation, and during this time the torch moves from the light width equal dividing position toward the bottom of the groove route. be done. This allows the sensing means to reliably detect the bottom surface of the groove root.
The torch is pulled back a predetermined distance from the detected bottom surface of the groove root, and the welding wire tip is positioned near the bottom surface of the groove root. Furthermore, the torch is moved again in the groove width direction from this pulled back position, and the sensing means detects the positions of each of the opposing groove surfaces, that is, the positions of both groove surfaces near the groove root position. .Then, the respective openings of the opposing groove surfaces are determined from the position data of the detected groove surface positions, the above-mentioned pullback distance, and the pre-input groove angle of the opposing groove surfaces. The tip root position is calculated, and the groove root gap is detected by calculating the distance between the two groove root positions.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 6.

FIG. 6 is a perspective view showing an example of a memory/reproduction type arc welding robot that implements the method according to the present invention. As shown in the figure, the arc welding robot (1) is an articulated arc welding robot. Main body (2), robot control device (3)
), welding type a (4) and teaching box (5)
It consists of Reference numeral (6) is a positioner, and a workpiece (7) having a groove in a v-shape, a diamond-shape, etc. is set in this positioner (6). Further, a torch (8) that supports and guides the wire (8a) is attached to the wrist portion of the arc welding robot body (2). The robot control device (3) equipped with a microcomputer includes a robot main body drive control unit that controls the position and orientation of the torch (8), a welding condition control unit that controls the output of the welding power source (4), and a teaching unit. A memory that stores teaching data such as the position and orientation of the torch (8), welding conditions, etc., which are manually taught by the box (5), and a control program for executing predetermined control including the method according to the present invention. Department, etc. are provided.

Furthermore, a sensing power source (not shown) is provided in the welding power source (4) to apply a sensing voltage between the torch (8) supporting the wire (8a) and the workpiece (7) during sensing. , inside the robot control device (3), the wire (8a) and the workpiece (
7) is provided with an energization detection device (not shown) that detects the energization state due to contact with and outputs the energization detection signal;
The sensing power source and the energization detection device constitute a sensing means for detecting the position of the workpiece.

Hereinafter, a method for detecting a groove root gap in a workpiece (7) according to the present invention, which is carried out by the above-mentioned arc welding robot (1), will be explained.

First, a method for detecting a groove root gap in a ■-shaped gap will be explained below with reference to FIGS. 1 to 3.

FIG. 2 is an explanatory diagram of the groove and teaching operation in a V-shaped groove. In the figure, (9a) and (9b) are opposing groove surfaces, and (9a) shows the groove angle θ1. (9b) is a second groove surface having a groove angle θ2. In addition, 0■ is the bottom surface of the groove root, and Ω1 is the first groove surface (
Groove root position 1.112 in 9a) is the second groove surface (9b)
At the groove root position, a V-shaped groove having a groove root gap W is formed by this groove root bottom surface 0ω and the above-mentioned opposing groove surfaces (9a) and (9b).

Then, the first workpiece (7
) is subjected to the following teaching operation.

That is, the wire (8a
) is set at a torch angle of approximately 90° with respect to the groove root bottom surface 00), that is, the torch posture is such that the torch (8) is approximately perpendicular to the groove root bottom surface 00,
As shown in Fig. 2, this torch (8) is moved vertically in the -Y force direction, the sensing start position PS is taught at the tip of the wire (8a) within the ■-shaped groove, and then the torch (8)
is vertically moved in the -Y force direction to position the tip of the wire (8a) on the bottom surface 0 of the groove root, and teach this position PT.

Next, the method for detecting the groove root gap of the ■-shaped groove in the workpiece (7) after performing the teaching operation as described above will be described with reference to the flowchart of the method according to the present invention in FIG. 1 and FIG. The method according to the present invention in the V-shaped groove shown in ) to (c) will be explained below based on explanatory diagrams. In addition, the first
During the explanation of the flowchart shown in the figure, N1, N2, --...
indicates the number of the processing procedure (step).

First, a torch (
8), apply a sensing voltage to (step Nl). Then, as shown in FIG. 3(a), the sensing start position W
From PS to teaching position PT, the torch (8) is moved vertically in the -Y direction, and the first opening and light surface (
9a) Detect (Step N2) 0 Then, the torch (
8) is pulled back a predetermined distance, for example, 2 seconds (step N3), and the torch (8) is moved in the groove width direction from this pulled back position. That is, the torch (8) is horizontally moved in the previously input -X direction from the pulled back position, the first groove surface (9a) is detected by the sensing means, and the detected first groove surface (9a )
The position data of position P1 is stored (step N4).

Next, the torch (8) is horizontally moved in the pre-input +X direction, the second groove surface (9b) is detected by the sensing means, and the detected position P2 of the second groove surface (9b) is detected. Store the data (step N5).

Then, as shown in Fig. 3, etc., a groove width equal dividing position P3 located at the center of the groove width is calculated from the above-mentioned stored groove surface positions P1 and P2, and the torch (8) is The wire (8a) is moved to position the tip of the wire (8a) at the groove width equidistant position 1tP3 (step N6).

Here, (for vertical P3, P3=Pl+(P2-Pi)
0 calculated by /2 Then, this groove width equally divided position P
3, the torch (8) is vertically moved in one Y direction input in advance, and the sensing means detects the groove root bottom surface 0ω (step N7). In this way, the groove width equally divided position P3 is obtained, and from this position P3, the torch (8) is moved at a predetermined angle (approximately 90' in this case) with respect to the groove root bottom surface 00). ) on the straight line formed in advance in the bottom surface 0 [D direction, the workpiece (7) can be mounted reliably even if there is an error when fixing it to the positioner (6). The groove root bottom surface Oo) can be detected.

After detecting the groove root bottom surface 0ω in step N7, the third
As shown in Figure (c), the torch (8) is pulled back a predetermined distance 1, for example, L=2 mm, and the wire tip of the torch (8) is positioned near the bottom surface QO of the groove root (Step N8). )0 Next, from this pulled back position, the torch (8) is moved again in the groove width direction. That is, by horizontally moving in one X direction that has been input in advance, the sensing means detects the first
The groove surface (9a) is detected, and this detected first groove surface (9a) is detected.
Store the position data of position P4 in a) (step N9
). Subsequently, the torch (8) is horizontally moved in the +X direction inputted in advance, and the sensing means detects the second groove surface (9b) near the groove root position Q2. (9b) The position data of the digit fP5 is stored (step Nl0).

Then, the position P4 of the first groove surface (9a) obtained in step N9, the predetermined pullback distance in step N8, and the groove angle θ of the first groove surface (9a) inputted in advance.
1, the groove root position Q1 of the first groove surface (9a) is calculated by calculation (step N11).

That is, in the XY plane shown in FIG. 3, the coordinate values of the position P4 of the first groove surface (9a) are P4 (X4, Y4),
The coordinate value of the groove root position opening l is expressed as Ql (XQI, Y
QI), the groove root position opening 1 is calculated by the following formula: XQI = χ4+(L/muanθ+)
-(1) YQI = Y4-L Next, the position P5 of the second groove surface (9b) obtained in step NIO, the predetermined pullback distance in step N8, and the second groove surface (9b) inputted in advance 9b) groove angle θ
, calculate the groove root position 02 of the second groove surface (9b) (step N12), that is, the coordinate values of the second groove surface (9b) (7) position P5 are calculated as
), the coordinate value of the groove root position ffQ2 is 02 (XQ2
, YO2), the groove root position 02 is calculated by the following equation.

XQ2 =X5-(L/l a nθ!)
-(2) Y opening 2=Y5-L Then, the distance between the above both groove root positions Q1.02 is calculated as the groove root gap W (step N15). Since the coordinate value Y (II) and the Y coordinate value Y (12) of the position Q2 are the same, it is only necessary to consider the X coordinate value. Therefore, the groove root gap W is calculated by the following formula.

W= l XQ2−XQI +
= (3) In this formula (3), the above formula (2) and formula (1) are added.
By substituting , the groove root gap W can be obtained.

Next, the groove root gap detection method according to the present invention for a diamond-shaped groove will be explained using the illustrations of the groove and teaching operation in a diamond-shaped groove shown in FIG. The method according to the invention in a shaped bevel will be briefly explained below based on an explanatory diagram. In addition, in FIGS. 4 and 5 (a) to (c), the same reference numerals are used for the same parts as in FIGS. 2 and 3 (a) to (c) above. .

That is, as shown in FIG. 4, the groove root bottom surface θ0 and the first groove surface (9a) perpendicular to this groove root bottom surface 00.
A groove having a groove root gap W is formed by a second groove surface (9b) facing the first groove surface (9a) and having a groove angle θ. Note that θ is the angle formed by the first groove surface (9a) and the second groove surface (9b). As shown in FIG. Set the torch posture so that the torch angle is approximately θ, = (θ, +θ/2) with respect to the bottom surface of the groove root (00), and move this torch (8) in the -Y direction on the straight line forming the angle θ. , a sensing start position ps in the diamond-shaped groove and a teaching position PT on the groove root bottom surface 00).

Then, as shown in FIGS. 5(a) to 5(c), this detected and memorized near the groove loop 1 position O1 of the first groove surface (9a) is performed in the same manner as described above. First groove surface (9
a) position WP4, the second groove surface (9b) (71 groove root position fiP5 detected and memorized near the groove root position IQ2, and the bottom surface of the groove root) The pullback distance fiL of the torch (8) from a0 and the groove angles θ1 and θ of the opposing groove surfaces (9a) and (9b) that have been input in advance
The groove root gap W in the bevel and mustard-shaped grooves can be determined. That is, since the X coordinate value of the groove root position Ql of the first groove surface (9a) is θ+-90@, it becomes Xfll-X4 according to the above formula (1), and
The X coordinate value of the groove root position 02 on the second groove surface (9b) is the value obtained by the above formula (2), so by substituting these values into the above formula (3), the groove root position The gap W can be determined.

As explained above, according to the method according to the present invention, the location of the first groove surface (9a) detected near the groove root position of the first groove surface (9a)? Since the groove root gap W is determined based on 1fP4 and 1fP5 of the second groove surface (9b) detected near the groove root position g2 of the second groove surface (9b), Groove angle θ1 of opposing groove surfaces (9a) and (9b) input in advance
, θ2 and the actual groove angle of each workpiece (7) due to processing accuracy, etc., the groove root gap W can be detected with accuracy that does not interfere with welding.

〔Effect of the invention〕

As described above, the groove root gap detection method according to the present invention is based on the position data of opposing groove surfaces detected by the sensing means in a storage/reproduction type arc welding robot equipped with a sensing means for detecting the workpiece position. The groove width equally divided position located in the center of both groove surfaces was determined, and the torch was moved toward the bottom of the groove root from this groove width equally divided position, so there was no error in mounting the workpiece. Even in such a case, the sensing means can reliably detect the bottom surface of the groove root. Then, the torch is pulled back a predetermined distance from the detected bottom surface of the groove root, and the position of the groove surface is detected by the sensing means near each groove root position on the opposing groove surface, and the position of the groove surface is detected near the groove root position. The groove root gap is calculated and determined based on the positions of both groove surfaces detected.

Therefore, according to the method according to the present invention, there is a difference in machining accuracy between the groove angle of the opposing groove surfaces inputted in advance and the actual groove angle of each workpiece, which is used to calculate the groove root gap. Even if there are errors caused by such factors, the groove root gap can be reliably detected with an accuracy that does not affect welding, so when welding, it is possible to properly weld each groove. can.

[Brief explanation of the drawing]

FIG. 1 is a flowchart of the method according to the invention,
FIG. 2 is an explanatory diagram of the teaching operation related to the method according to the present invention and the groove in the ■-shaped groove, and FIGS. 3(a), (b) and (
c) is ■Explanation/routing of the method according to the present invention for a shaped groove, FIG. )as well as(
c) Illustration of the method according to the invention in a chopper groove,
FIG. 6 is a perspective view showing an example of a memory/reproduction type arc welding robot that implements the method according to the present invention; FIG. 7 is an explanatory diagram of a teaching operation related to a conventional groove root gamble detection method for a V-shaped groove; FIG. 8 is an explanatory diagram of a conventional groove root gap detection method for a ■-shaped groove. (+)-1 memory/regeneration type arc welding robot, (21-
Arc welding robot main body, (3) - one robot control device, (4) - welding power source, (5
)--teaching pendant, (6)-positioner, (
7)・-Work, (8)・・・Torch, (8a)・・−
Welding wire, (9all--first groove surface, (9b)-second groove surface, 00-groove root bottom surface, mouth 1, ro 2-groove root position, W-groove root gap. 2nd figure

Claims (1)

[Claims] 1. A sensing voltage is applied between a torch that supports a welding wire set to a predetermined protrusion length and the workpiece, and the energization state due to contact between the welding wire and the workpiece is detected to determine the workpiece position. A memory/regeneration type arc welding robot that detects the groove root gap of a groove formed by the opposing groove surface and the groove root bottom surface using a memory/regeneration type arc welding robot equipped with a sensing means for detecting 1. A groove root gap detection method using a memory/regeneration type arc welding robot, characterized by performing the following steps. (a) A step of moving the torch in the groove width direction of the groove, detecting the positions of each of the opposing groove surfaces by the sensing means, and obtaining the position data. (b) From the position data of both groove surfaces. Step (c) of calculating and finding equal division positions in the groove width direction: Move the torch toward the bottom of the groove root from this position of equal division in the groove width, and after detecting the bottom of the groove root by the sensing means, move the torch. step (d) of pulling back the welding wire a predetermined distance to position the tip of the welding wire near the bottom of the groove root; (d) moving the torch again in the groove width direction from this pulled back position, and detecting the opposite groove surface using the sensing means; Step (e) of detecting each position and obtaining the position data; the double groove surface position data obtained in step (d) above, the pullback distance in step (c) above, and the opposing face input in advance. Step (f) Calculating and detecting the distance between these two groove root positions as a groove root gap from the groove angle of the groove surface to calculate the groove root position of each of the opposing groove surfaces. step.