JPS62114771A - Touch sensing idle swing preventive type control method for welding robot - Google Patents

Abstract

PURPOSE:To prevent an idle swing from being executed even to a comparatively difficult plate thickness surface by executing a sensing operation of a wide surface part, and thereafter, shifting a wire by a moving extent of the sensing operation, and executing the next sensing operation. CONSTITUTION:At the time of teaching, an X direction sensing operation is executed extending from a start point B of a touch sensing operation of the tip of a wire 3 to an end point C where it contacts the surface 1a of a base metal, and an X direction shift quantity of the base metal 1 is stored. Subsequently, an operation of a Y direction is executed extending from a start point D of a sensing operation of the tip of the wire 3 to an end point E where it contacts the plate thickness surface 1C of the base material, and a Y direction shift quantity of the base material 1 is stored. Next, at the time of play-back, the sensing operation in the X direction is executed to the part of the surface 1a extending from the start point B to the end point C1, and a shift quantity l extending from the point C to the point C1 is derived. Thereafter, at the time of the touch sensing operation in the Y direction to the plate thickness surface 1C, the start point D is moved to a point D1 by l, the sensing operation in the Y direction is executed extending from D1 to the point D1 where it contact the plate thickness surface 1C, and a Y direction shift quantity of the base material 1 is derived.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a touch sensing control method for detecting the amount of positional deviation of a base material of a welding robot.

In particular, the present invention relates to a touch sensing control method for preventing missed welding of a welding robot, which is suitable for detecting the amount of positional deviation of a base material in five-dimensional directions.

[Background of the invention]

A conventional touch sensing control method for a welding robot is illustrated in FIG. In Fig. 4, in a robot control device that generally has a vertical sensor that detects the position of the base metal by generating a high voltage between the welding wire and the base metal and detecting the position of the base metal when the two come into contact, an apex A of the base metal 1 is used. When detecting the position of
X perpendicular to α, 1h, and 1c, respectively.

The position of point A can be determined by performing touch sensing from the Y and Z directions.

However, in the conventional method, when the sensor operation position is determined by touch sensing during teaching, the surface of the base material 1 generally has a surface 1α, a portion 1h, a thickness surface 1C, etc., and the surface 1α.

Regarding part 1b, touch sensing is relatively easy because the sensing surface is wide, but since the sensing surface is narrow with respect to plate thickness surface 1C, the wire and base material 1 often miss due to misalignment of the base material 1. There was a problem that touch sensing was not possible.

C. Object of the Invention The purpose of the present invention is to solve the problems of the prior art described above, and to prevent touch sensing of a welding robot that performs control to prevent the wire and base material from erecting during touch sensing of a welding zero-bot control device. To provide an expression control method.

[Summary of the invention]

In the present invention, the surface of the weld base metal generally has a surface part and a plate thickness side, and sensing can be performed relatively easily on the surface part, but the sensing surface is narrow on the plate thickness side and there is no error. Focusing on the point that this is often the case, we perform touch sensing on the surface portion without twisting, calculate the sensing result in the corresponding direction from the sensing result, and then shift the wire position by the amount of movement for the next touch sensing and perform sensing operation. row fH
In addition, for the next touch sensing, the wire position is shifted by the cumulative amount of movement and sensing is performed.
This is a touch-sensing control method for preventing welding robots that can sense the wire and the base material on relatively difficult plate thickness surfaces without causing them to miss. [Example of the invention] One embodiment of this will be explained with reference to FIGS. 1 to 5.

FIG. 1 is an explanatory diagram showing an operational outline of an embodiment of the touch-sensing missed-run prevention control method for a welding robot according to the present invention. In Fig. 1, a case is illustrated in which the positional deviation view AAi of the vertex A of the base material (work) 1 is obtained, and the broken line indicates the position of the base material 1 during teaching and the welding that detects the position of the vertex A of the base material 1. The touch sensing operation of the tip of the wire 5 of the torch 2 is shown, and the solid line indicates the welding torch 2 that detects the position of the base material 1 and the position of the apex A1 of the base material 1 during playback.
The touch sensing operation of the tip of the wire 3 is shown.

First, during teaching, a sensing operation is performed in the X direction from the start point B of the touch sensing operation of the tip of the wire 5 of the welding torch 2 shown by the broken line to the end point C where it contacts the surface 1α of the base material 1. Detect and memorize the shift amount〇Continue sensing operation in the Y direction from the start point of the touch sensing operation of the tip of the wire 5 of the welding torch 2 to the end point E where it contacts the plate thickness surface 1C of the base material 1. Then, the shift amount of the base material 1 in the Y direction is detected and stored.

Next, during playback, according to the present invention, first, the touch sensing operation of the tip of the wire 5 of the welding torch 2 shown in the solid line is performed in the X direction from the start point B to the end point C1 where it contacts the surface 1α of the base material 1. The sensing operation is performed, and from the result, the shift amount (positional deviation amount) t from point C to point C in the X direction of the base material 1 is determined. After that, plate thickness side 1
During the touch sensing operation in the Y direction for c, the present invention moves the start point of the touch sensing operation at the tip of the wire 5 of the welding torch 2 to the shift amount (positional deviation amount) t in the X direction to the bending start point D1. Then, a sensing operation is performed in the Y direction from the starting point D1 after movement to the end point D1 where it contacts the plate thickness surface 1C of the base material 1, and based on the result, the sensing operation is performed in the Y direction.
Find the shift t (positional deviation 荀°) in the Y direction.

When determining the positional deviation amount AA1 of the vertex A of the base material 1 in this way, if the sensing operation in the Y direction is performed on the plate thickness surface 1C using the result of the tassing operation on the surface 1α in the X direction, then Plate thickness surface 1c, which was previously difficult
Even when the wire 5 tip of the welding torch 2 and the base metal 1 do not swing in vain, it is possible to perform evening and I-chip sensing.

In the above embodiment, the touch sensing operation in the X and Y directions will be described. However, if the touch sensing operation in the Z direction is also performed, the touch sensing operation in the X direction is first performed on the surface 1α of the base material 1 in the same manner. Then, if necessary, use the results to perform a touch sensing operation in the Z direction on the surface 1h, and then move the tip of the wire 5 of the welding torch 2 by the shift amount of the sensing results in the X and Z directions to touch the plate. What is necessary is to perform a touch sensing operation of Y foot on the thick surface 1C.

FIG. 2 is an overall robot sterilization block diagram showing an embodiment of the touch-sensing missed-run prevention control method for a welding robot according to the present invention.

In Figure 2, -! ! When the robot control device is manually operated, the joint command value or orthogonal command value changes depending on the operation mode. If the operation mode is orthogonal, the orthogonal command value is further converted into a joint command value. Next, the deviation is calculated from the joint command value and the robot's current value, and the deviation amount is converted into a format and becomes a manipulated variable to activate the actuator. As a result, a pulse is generated from the encoder and the current value of the robot is updated. During playback, the teach data stored as joint angles is converted to one-way orthogonal data, and if there is a shift, the shift amount stored in the shift register is added to become the orthogonal command value. . In this way, the actuator is activated through the above procedure, and the teach point can be shifted during playback.

Next, a method of calculating the shift amount using touch sensing of the robot control device will be explained. FIG. 3 is an explanatory diagram of a method of calculating a shift amount (positional deviation amount) by touch sensing of the base material (work) 1 in FIGS. 3 and 1; FIG. In Figure S, the base material (
Workpiece) A touch in which the tip of the wire 5 of the welding torch 2 in playback touches the base metal 1 in the direction from the start point P of the touch sensing operation by the tip of the wire 5 of the welding torch 2 in workpiece 1 to the end point P1 of the touch sensing operation in teaching. The sensing operation is performed until the sensing operation end point P2.Now, the touch sensing operation H of the tip of the wire 5 of the welding torch 2
From the starting point P C2+JJ'+ , , h ) to the teaching touch sensing operation end point P1. (χ2 +;
72 + 22), and the playback touch sensing operation end point P2 (Town +
Suppose that the tip of the wire 5 of the welding torch 2 comes into contact with the point P1 of the base material 1 at this time (positional deviation amount) S (83, Sy, S)
can be calculated using the following equation (1).

1'Sz = smell - z2 This shift amount 8C8χ, sy, S, )) is stored in the shift register. Note that if the shift amount has already been set in the shift register, the value of the shift l described above is accumulated. In this way, as shown in FIG. 1, during playback, the sensing operation from the touch sensing operation start point B to the end point C to detect the shift) t in the X direction of the base material 1 indicated by the broken line, and the sensing operation A touch sensing operation for detecting the amount of shift in the direction is performed from the start point to the end point E, and each shift amount is stored. When playback is performed in this way, first, a sensing operation is performed in the X direction of the base material 1 indicated by the solid line from the start point B to the end point C+-4, and as a result, the shift amount (positional deviation amount) in the X direction is recorded in the shift register. Find t. Next, the shift amount in the X direction just found (
The welding torch 2 is moved by positional deviation amount) t, and the sensing operation is performed from the touch sensing start point D1 to the end point E1 in the Y direction, and the tip of the wire 5 of the welding torch 2 and the plate thickness surface 1C of the base material 1 are aligned. Upon contact, the resulting Y-direction shift 'jk (positional deviation fr) is added to the shift register. As described above, the touch sensing operation is performed without the tip of the wire 5 of the welding torch 2 and the base material 1 swinging inadvertently, and the shift amount (positional deviation amount) of the top layer A of the base material 1 is determined.

〔Effect of the invention〕

According to the present invention, it is possible to perform control to prevent the wire and base material from swinging inadvertently during touch sensing of a robot control device having a touch sensor that detects the position of the base material, so that the robot can be operated in the production line. If you miss the touch sensing operation during the process, a sensing error will occur and the robot will stop, which can prevent the entire production line from stopping. Even when used as a stand-alone device, sensing errors are reduced, resulting in a high operating rate.

[Brief explanation of drawings]

FIG. 1 is an operational overview explanatory diagram showing an embodiment of the touch sensing miss-run prevention control method for a welding robot according to the present invention, FIG. 2 is a robot control block diagram, and FIG. 5 is a diagram showing the shift amount of the touch sensing operation. Explanatory diagram, 4th
The figure is an operational overview diagram illustrating a conventional touch sensing control method for a welding robot. 1... Base material, 1α, 1b... Base material surface, 1C...
Base material plate thickness surface, 2... Welding torch, 5... Wire, t
...X direction shift amount.

Claims (1)

[Claims] In a control device for a welding robot that has a touch sensor that detects the position of the base metal by generating a high voltage between the welding wire and the base metal and detecting the position of the base metal when the wire comes into contact with the base metal, when touch sensing the base metal, the surface part is first detected. After performing a sensing operation on a wide part of the sensing surface, such as, the wire is shifted by the amount of movement of this sensing operation, and sensing operation is performed on a part including a narrow part of the sensing surface, such as the next board thickness surface, to prevent missed swings. A touch sensing control method for preventing missed welding of a welding robot.