JPS6021182A - Detection of welding position and welding route with welding robot - Google Patents

Abstract

PURPOSE:To cope adequately with the change in the shape of a work and the deviation in positioning by detecting the shape of the work and the condition of positioning thereof with sensors and determining the position to be welded and the welding course by calculation. CONSTITUTION:A torch is moved in the direction F1 from a preliminarily taught operation start point K1 and the point S1 on a surface M2 when the torch contacts with a work is detected. The torch is immediately moved in the opposite direction and when the torch returns to the point K1, the direction is changed toward F2 and the point S2 on the surface M1 is detected. The torch is thereafter returned and the point S3 via the point K2 at a specified distance from the point S2 is detected. The points S4, S5, S6 on the surface M1 or M2 are thereafter successively detected in the same manner. A straight line L2 is calculated by the calculation equation if the positions of the three points not on one straight line on the respective surfaces constituting the work are known by the above-described procedure. Since the weld line is the part where the work on the straight line L2 exists, the line L2 is sensed with a magnetic sensor, and the point P1 or P2 where the work is discontinuous is detected, by which the weld line is determined.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to the detection of the welding position and welding path of a workpiece in a welding robot, particularly when the workpiece has a shape error and a complicated error occurs in its positioning. The present invention relates to a method for detecting a welding position and a welding route suitable for.

[Background of the invention]

The conventional method for detecting the welding position in a welding robot is to measure and record the distance between the teach point and the workpiece using a sensor that can measure the distance between the workpiece and a single point, such as a magnetic sensor or touch sensor! Then, the distance to the workpiece was measured using the same method during welding, the amount of deviation was calculated, and this amount of deviation was used as the amount of workpiece position correction.

This method has the disadvantage that correct position correction cannot be performed when the shape of the workpiece has an error compared to that during teaching or when the positional deviation is complicated.

[Purpose of the invention]

An object of the present invention is to provide a method for detecting welding positions and welding paths that can accurately deal with changes in the shape of a workpiece or complicated positioning errors when a welding robot detects a welding location on a workpiece using a sensor. I have a lot to offer.

[Summary of the invention]

The present invention uses a sensor to sense the surface of each surface that makes up the workpiece during welding, determines the equation of the surface by determining the coordinate values of the fish school existing on the surface, and calculates the intersection line of those surfaces. By formulating the welding line equation, it was possible to accurately deal with changes in the shape of the workpiece and positioning deviations.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows the hardware configuration of a welding robot used in this embodiment, in which a robot body 1 is controlled by a control device 2. As shown in FIG. The control device 2 also carries the positioner control device 1 and the arc welding machine 3, and controls these devices at the same time.

In FIG. 1, 5 is a positioner, 6 is a welding torch (hereinafter referred to as torch), and 7 is a sensor control circuit.

Next, FIG. 2 is an enlarged view of the robot's torch 6, which includes a welding wire (hereinafter referred to as wire) 10, which is the contact part of the touch sensor that can confirm the contact between the workpiece and the torch 6, and a Magnetic sensors 8 and 9 are attached that can measure the distance to the torch. In addition to the contact detection function of the touch sensor, the wire 10 has an original function as a welder during welding. The control circuit main body 7 for the touch sensor and the magnetic sensor is housed in the control device 2, as shown in FIG.

With the above hardware configuration, the welding work is performed by sensing the welding surface of the workpiece.

FIG. 6 shows the shape of the welding workpiece used in this example, and shows the horizontal fillet shape. Symbol S.

S6 indicates a point on the welding surface M1 and M2 of the workpiece, and is a point to be detected using a sensor in order to detect the weld line. Point P and point P are the start and end points of welding. Figure 4 shows the movement of the wire tip when detecting the detection points from point S1 to point S6 using a touch sensor. There is. The broken line section represents the work shown in FIG. 6, and the arrow line section represents the direction in which the torch moves.

The procedure for the detection operation from point S1 to point S''4 is as shown in Fig. 4. First, move the torch in the taught direction F1 to the operation start point that has been taught in advance, and then insert the wire. When the tip contacts the workpiece, detect point S1 on surface M2. After detecting 0, immediately move the torch in the opposite direction and return to the point. Next, change direction to the teaching direction F. Move the torch to point S on plane M1,
Detect. Thereafter, the torch is returned to the point S, and a point S3, which is oriented in the direction F1, is detected via point S and 2, which are a certain distance apart.

Thereafter, in the same manner, point KB+K4 is used as a waypoint for torch movement, and plane M or point S4+S6 on plane M is moved.
t 86 are detected in descending order of subscript number.

If you know the positions of the three points on each surface of the workpiece that are not on a straight line using the above procedure, you can use a commonly known calculation formula to calculate the equation of the straight line formed by the intersection of the 2,000 surfaces. It is possible to calculate the straight line. Since the weld aLI is the part where the workpiece is located on the straight line L2, the magnetic sensor senses the line L2 and detects the point P where the workpiece breaks.
If I or P is detected, the welding line L1 can be determined.

When welding only part of the weld line, point P.

Alternatively, if the welding skip distance and welding distance from P to the welding point are taught in advance, the desired welding line can be calculated. - Next, FIG. 5 shows the shape of the workpiece used in another example. This work has the surface M 3 + M'4 + M
It consists of three planes: ll. As in the previous example, the point with the symbol S is a detection point set by the touch sensor, and the point with the symbol is a transit point of the tip of the wire when performing a detection operation.

In the same procedure as in the above example, the torch is moved from the operation start point 6 in FIG. 6 in the taught sense direction F, or F, or F, and from point S to 81. From the detection point of 6 to the point 6, go up jllKll via the waypoint of . Point S on surface M? +5lop”+4, surface M4
Above, point s, , 813181B, on surface M, point "0"
1 Sll+ Sl! Since the coordinates of the six points that are not on a straight line on each surface are rounded, the equation for each surface is determined, and the intersection lines of the surfaces, , L, , Lll can be calculated. Also, at the same time [the intersection 0 of the three intersecting lines is circled.

The desired welding line is a line segment "j* L4e L5 whose end point is the intersection O on the intersection line L6 * L71 L@, so
If the welding distance is taught in advance, all welding lines are determined by internal calculations.

Using a sensor as described in the above embodiments, it is possible to detect points on the surface of the workpiece and set the welding line, so even if the positioning of the workpiece is shifted in any direction, the workpiece itself Even if the shape of the workpiece contains errors, it is possible to calculate and detect the correct welding position of the positioned workpiece.

Furthermore, unlike conventional correction methods, the method of this embodiment does not correct the teaching point, so it is possible to accurately detect the welding position and determine the welding path without being limited by the types of errors that can be corrected. can do.

Therefore, according to this embodiment, the following effects are achieved.

(1) Even if the shape of the work to be welded changes and positioning shifts occur in multiple directions, the correct welding position and welding path can be detected.

(2) Since errors in workpieces in multiple directions can be corrected, the positioning accuracy of the positioner may be low, so external welding is useful for simplifying equipment.

(6) Even when you want to perform complicated error correction, simple teaching is enough.

(4) If the workpiece is made up of flat surfaces, all welding positions can be detected using the same algorithm, so the structure of the detection software can be simplified. (5) Accurate welding positions can be detected, so welding This improves the finishing accuracy of the parts, reduces work errors, and improves work efficiency.

(6) Since there is no need to sense the workpiece during teaching, sensing time can be shortened.

According to the present invention described above, in a welding robot equipped with a sensor capable of detecting at least the positioning state of a workpiece, information regarding the shape of the workpiece and the welding position M of the workpiece can be obtained.
By teaching relevant information and using sensors to detect the shape and positioning of the workpiece during welding, the welding position and welding route can be determined, so → It is also highly effective in accurately dealing with changes in the shape of the steering wheel and misalignment in positioning.

[Brief explanation of the drawings] Figure 1 is a system block diagram of the welding robot, Figure 2 is an enlarged view of the torch attached to the welding robot, and Figure 3 is a perspective view showing a horizontal fillet-shaped workpiece as an example of the workpiece. ,
Fig. 4 is an explanatory diagram of the sensing operation when sensing the workpiece shown in Fig. 3, Fig. 5 is a perspective view showing a workpiece consisting of six sides as another example of a wafer, and Fig. 6 is a diagram illustrating the sensing operation when sensing the workpiece shown in Fig. 3. FIG. 3 is an explanatory diagram of sensing operation when sensing the workpiece shown in FIG. DESCRIPTION OF SYMBOLS 1... Robot body, 2... Control device, 6... Arc welding machine, 4... Positioner control device, 5... Positioner, 6... Torch, 7... Sensor control circuit Main body, 8゜9...Magnetic sensor, 10...Wire, S
,~1. ...Sense point, K1-. ...Sense operation start point and transit point, Pl...Welding start point, P, ...Welding end point, M, ~,...Work surface, L, ~7...Welding line and surface Intersection line, F1~. ...Sense direction $ 1 Figure θ Figure 2 Figure 4

Claims (1)

[Claims] A welding robot equipped with a sensor capable of detecting at least the positioning state of the workpiece to be welded is taught information about the shape of the workpiece and information about the welding position of the workpiece, and the shape and positioning state of the workpiece are taught at the time of welding. A method for detecting welding positions and welding routes in a welding robot, characterized in that the welding position and welding route are calculated by detecting the welding position and welding route using a sensor.