JP2003039354A - Robot control method, control device and jig - Google Patents

Abstract

(57) [Summary] [PROBLEMS] When the actual tip position is deviated from the reference teaching position due to deformation due to replacement or collision of a welding torch,
Provided are a control method, a control device, and a jig for a robot that can automatically calculate a correction amount of a deviation without performing visual alignment or the like and can increase productivity in a welding process. When an actual tip position is deviated from a reference teaching position due to replacement of a welding torch or deformation due to a collision, the robot operates in a predetermined operation pattern so that a welding wire comes into contact with a recess. For example, the robot 1 is stopped. In this way, the amount of movement from the reference teaching position to the point where the robot 1 is stopped is stored, and the amount to correct the displacement of the welding torch is calculated from the amount of movement.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a robot control method for performing arc welding, a control device, and a jig used for the control device.

[0002]

2. Description of the Related Art If a welding torch attached to the tip of a robot arm is deformed or replaced and a displacement occurs between the tip position of the welding torch and the initial tip position, the original teaching data Is disclosed in Japanese Patent Publication No. 7-4781 and Japanese Patent Laid-Open No. 8-255011 to correct the motion of the robot so that the reproducing operation can be performed by using the above. In these techniques, the amount of displacement after replacement or deformation is calculated by manually moving the torch tip position after the displacement has occurred to a reference position taught in advance. However, these techniques are premised on manual positioning work by visual observation, and no consideration was given to automation of correction work.

Techniques for automating this correction work include:
There is a technique in which a welding wire protruding from a welding torch is used as a contact sensor and a jig designed specifically for correction work is brought into contact with the jig to automatically calculate the amount of displacement of the tip position. In this technique, as shown in FIG. 5, it is necessary to perform a contact operation in the three directions of X, Y, and Z with respect to the above-mentioned dedicated jig in order to detect the amount of displacement in the three-dimensional space.
The number of operations is at least 7 including the approaching operation to the teaching reference position. In order to improve the production efficiency in the welding process, it is desirable that this number be as small as possible.

[0004]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to fix the welding torch attached to the arm tip of a robot between the tip position of the welding torch and the initial tip position due to deformation or replacement. If a position deviation occurs in the robot, it is possible to automatically calculate the amount to correct the robot motion so that the original teaching data can be used as it is for playback operation, and the robot motion required for the calculation. It is an object of the present invention to provide a robot control method, a control device, and a jig used for the same, which can reduce the number of times.

[0005]

According to a first aspect of the present invention, there is provided a robot control method for reproducing a robot motion based on pre-stored robot teaching data. A process in which a jig with a certain conductive contact plate is installed near the robot, the welding torch attached to the tip of the wrist of the robot is positioned at a predetermined position in the recess, and the teaching data at that time is stored as the reference teaching position. When the actual tip position deviates from the reference teaching position due to welding torch replacement or deformation due to collision,
Move the robot to the stored reference teaching position, operate the robot in a predetermined motion pattern, and stop the robot if the welding wire protruding from the tip of the welding torch and the surface of the recess come into contact with the robot. It includes a process of storing the amount of movement to the point where the robot is stopped and calculating an amount for correcting the deviation amount of the welding torch from the amount of movement.

According to the robot control method of the first aspect, the welding torch attached to the tip of the arm of the robot is deformed or exchanged, so that the welding torch is located between the tip position and the initial tip position. When the positional deviation occurs, the welding wire is operated in a predetermined operation pattern in the recess of the jig, and the movement amount of the robot is calculated from the operation until the welding wire comes into contact with the surface of the recess.
The original teaching data can be used as it is for replaying, the amount of robot motion correction can be automatically calculated, and the number of robot motions required for the calculation can be reduced. Therefore, the productivity in the welding process can be improved.

According to a second aspect of the present invention, in the robot control method according to the first aspect, when the robot is stopped, a sensing voltage is applied to the conductive contact plate and the welding wire, and the welding wire and the conductive contact plate come into contact with each other. This is done by detecting the flowing sensing current.

According to the robot control method of the second aspect, the same effect as that of the first aspect can be obtained.

According to a third aspect of the present invention, there is provided a robot control method according to the first aspect, wherein a predetermined operation pattern for calculating an amount for correcting the deviation amount of the welding torch is realized by a welding torch having a deviation. a reference teaching position as the origin of the corrective action, to operate until the recess and the welding wire to a defined Y-axis positive direction is in contact with the recess, then the recess <br/> the Y axis negative direction and the welding wire contacts Until the contact between the recess and the welding wire in the X-axis positive direction defined on the recess from the origin of the correction operation. According to the robot control method of the third aspect, there is the same effect as the first aspect.

According to a fourth aspect of the present invention, there is provided a robot control device for reproducing a robot motion based on previously stored robot teaching data, wherein a conductive contact plate having a conical concave portion is provided. By holding the jig and the welding torch attached to the tip of the wrist of the robot at a predetermined position in the recess and storing the teaching data at that time as the reference teaching position, the welding torch is replaced or deformed by collision. When the actual tip position deviates from the reference teaching position, the robot is moved to the stored reference teaching position, the robot operates in a predetermined operation pattern, and the welding wire and the concave portion protruding at the tip of the welding torch Corrective action execution means to stop the robot if the surface touches, and the amount of movement from the reference teaching position to the point where the robot is stopped And, those having a correction amount calculating means for calculating an amount for correcting the shift amount of the welding torch from the amount of movement.

According to the robot controller of the fourth aspect, the same effect as that of the first aspect can be obtained.

According to a fifth aspect of the present invention, there is provided a robot control device according to the fourth aspect, wherein the means for stopping the robot when the welding wire and the recess contact each other includes a conductive contact plate and a sensing power supply for applying a sensing voltage to the welding wire. It has a contact detection means for detecting a sensing current flowing when the welding wire and the jig come into contact with each other.

According to the robot controller of the fifth aspect, the same effect as that of the fourth aspect can be obtained.

According to a sixth aspect of the present invention, in the robot control apparatus according to the fourth aspect, the correction operation executing means for calculating the amount of correction of the deviation amount of the welding torch is the reference teaching realized by the welding torch having the deviation. The position is the origin of the correction operation,
Operate until the recess and the welding wire make contact in the Y-axis positive direction defined on the jig, and then in the Y-axis negative direction until the recess and the welding wire make contact, and then move from the origin of the correction operation to the recess The welding wire is operated in the positive direction of the X-axis defined in (3) until the recess and the welding wire come into contact with each other.

According to the robot control apparatus of the sixth aspect, the same effect as that of the fourth aspect can be obtained.

According to a seventh aspect of the present invention, when the operation of the robot is reproduced based on the previously stored teaching data of the robot, the actual tip position is changed from the reference teaching position by the replacement of the welding torch or the deformation caused by the collision. A jig for determining the amount of deviation when displaced, comprising a conductive contact plate having a conical concave portion in which the welding torch operates and contacts in a predetermined operation pattern from a predetermined position, The shift amount can be obtained from the movement amount from the predetermined position to the contact position.

According to the jig described in claim 7, the same effect as in claim 1 can be obtained.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a robot to which the present invention is applied and its control device. In FIG. 1, 1 is a robot,
Reference numeral 2 is a welding torch, 3 is a robot control device, and 4 is a detection device including a jig having a conductive contact plate 8 having a conical recess 8a, a sensing power supply, and a contact detection means. The robot 1 is connected to the control device 3 and its operation is controlled, and the detection device 4 is connected to the control device 3.

FIG. 2 shows the structure related to the present invention in the control device 3 and the detection device 4. In FIG. 2, 8 is a conductive contact plate having a conical recess 8a in the jig, and 9 is a jig having the conductive contact plate 8 and the welding wire 1.
1 is a sensing power source for applying a sensing voltage, 10 is a contact detecting means for detecting a sensing current flowing when the welding wire 11 and the conductive contact plate 8 are in contact, and 5 is a welding torch 2 attached to the robot 1. Storage means for positioning the teaching data at that position in the device 4 as a reference teaching position and 6 for moving the robot 1 to the stored reference teaching position and moving the robot 1 in a predetermined operation pattern Corrective action executing means to operate,
Reference numeral 7 is a correction amount calculation means for storing a movement amount from the reference teaching position to a point where the robot 1 is stopped and calculating an amount for correcting the deviation amount of the welding torch 2 from the movement amount. The relationship between these components will be described according to the processing flow shown in FIG.

In step S1 shown in FIG. 3, the welding torch 2 attached to the robot 1 is positioned at a predetermined position in the detection device 4 before the welding torch is replaced or deformed, and teaching data at that time is set. Is stored in the storage means 5 as a reference teaching position. If the actual tip position deviates from the reference teaching position due to the deformation of the welding torch 2 due to the replacement or collision in the process S2, the correction operation executing unit 6 causes the reference teaching stored in the storage unit 5 in the process S3. The robot 1 is moved to the position. Next, in process S4, the robot 1 is also operated by the correction operation execution means 6 in a predetermined correction operation pattern. At this time, when the welding wire 11 and the conductive contact plate 8 come into contact with each other, the contact detection signal 10 is output to the correction operation execution means 6 from the contact detection means 10, and the correction operation execution means 6 stops the robot 1 and in step S5. The movement amount from the reference teaching position to the point where the robot 1 is stopped is stored.

Next, the correction operation pattern executed by the correction operation executing means 6 will be described with reference to FIG. Figure 4
4A is a cross-sectional view of the conductive contact plate 8 having a conical recess 8a, and FIG. 4B is a top view. FIG. 4 (a),
As shown in (b), the reference teaching position P0 is taught on the center line of the cone and at the middle point in the height direction. A reference teaching position realized by the welding torch 2 in which a positional deviation exists due to replacement or deformation of the welding torch 2 is represented by o as the origin of the correction operation. The correction operation pattern is operated from the correction operation origin o in the Y-axis positive direction defined on the recess 8a of the jig until the recess 8a and the welding wire 11 come into contact with each other, and then welds the recess 8a in the Y-axis negative direction. Operate until the wire 11 touches,
Next, the correction operation is performed from the origin o in the positive direction of the X-axis defined on the recess 8a until the recess 8a and the welding wire 11 come into contact with each other.

Next, an algorithm for calculating the correction amount of the welding torch 2 from the movement amount obtained by executing the correction operation pattern will be described with reference to FIG. Conductive contact plate 8
Has a conical shape, and has a circular shape from above as shown in FIG.

The amount of movement when the correction contact is moved in the positive direction of the Y-axis from the origin o and comes into contact with the conductive contact plate 8 with Pl, yl,
When the movement amount when the Y-axis is moved in the negative direction and the conductive contact plate 8 is in contact with P2 is y2, and the movement amount when the X-axis positive direction is in contact with the conductive contact plate 8 and P3 is x, The vector from the correction operation origin o to each contact point is expressed as in equations (1), (2), and (3).

Pl = (0, yl) (1) P2 = (0, y2) (2) P3 = (x, 0) (3) If the torch 2 is deformed only by displacement of position. , P
l, P2, and P3 exist in the same plane whose normal is the height direction of the cone. If you know the coordinates of 3 points on the plane, 3
The radius and center coordinates of a circle passing through the points can be calculated by a simple calculation.

This central coordinate is defined as Cp and is expressed by the equation (4),
Let R be the radius.

Cp = (Cpx, Cpy) (4) Since the coordinates shown by the equations (1), (2) and (3) have the origin o of the correction operation as the coordinate origin, the central coordinates Cp It can be seen that the value of is the projection component of the vector toward the reference teaching position P0 on the XY plane as shown in FIG. Further, since the circle passing through the coordinates of the three points has a conical cross section, its radius is proportional to the height. As shown in FIG. 4A, when the angle formed by the cone and the horizontal plane H is θ, the relationship between the height h and the radius R is expressed by equation (5).

H = Rtan θ (5) If the height of the reference coordinate position from the horizontal plane H is ho, then h
It can be seen that the difference between o and h is the correction amount in the Z direction.

From the above, the amount by which the positional deviation is corrected is expressed by the equation (6).
Required by.

Correction amount = (Cpx, Cpy, ho-h) (6) The required number of operations in this case includes the approach operation from the standby position set near the jig to the correction operation origin o. From the corrective operation origin o to Pl, from Pl to P2, from P2 to corrective operation origin o, from corrective operation origin o to P3, from P3 to corrective operation origin o, a total of 6 operations are performed.

[0031]

According to the robot control method of the first aspect of the present invention, the welding torch attached to the end of the arm of the robot is deformed or replaced, and the tip position of the welding torch and the initial tip position are changed. If a misalignment occurs,
The welding wire is operated in a predetermined movement pattern inside the recess of the jig, and the movement amount of the robot is calculated from the operation until the welding wire comes into contact with the surface of the recess. It is possible to perform the regenerating operation by automatically calculating the amount to correct the robot operation, and to reduce the number of robot operations required for the calculation, thus improving the productivity in the welding process. Can be increased.

According to the robot control method of the second and third aspects, the same effect as that of the first aspect can be obtained.

According to the robot controller of the fourth aspect, the same effect as that of the first aspect can be obtained.

According to the robot control device of the fifth and sixth aspects, the same effect as the fourth aspect can be obtained.

According to the jig described in claim 7, the same effect as in claim 1 can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an embodiment of a robot controller to which the present invention is applied.

FIG. 2 is an explanatory diagram illustrating configurations of a control device and a detection device of the robot.

FIG. 3 is a flowchart illustrating a method of controlling the robot when the welding torch is displaced.

4A is a sectional view of a conductive contact plate, and FIG. 4B is a top view.

FIG. 5 is an explanatory diagram illustrating a conventional example.

[Explanation of symbols]

1 robot 2 welding torch 3 Robot controller 4 detector 5 storage means 6 Corrective action execution means 7 Correction amount calculation means 8 Conductive contact plate 8a recess 9 Sensing power supply 10 Contact detection means 11 welding wire 12 Contact detection signal

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Atsumi Hashimoto             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F-term (reference) 3C007 AS11 BS12 KS17 KS31 KV04                       KX19 LT14 LT17 MS15 MT04

Claims (7)

[Claims] 1. A control method for the robot, which reproduces the operation of the robot based on pre-stored teaching data of the robot, wherein a jig having a conductive contact plate having a conical recess is provided in the robot. A process of positioning the welding torch, which is installed in the vicinity of the robot and attached to the tip of the wrist of the robot, at a predetermined position of the concave portion, and storing teaching data at that time as a reference teaching position, and replacement or collision of the welding torch. When the actual tip position deviates from the reference teaching position due to deformation,
The robot is moved to the stored reference teaching position, the robot is operated in a predetermined operation pattern, and the robot is stopped when the welding wire protruding from the tip of the welding torch comes into contact with the surface of the recess. Then
A method of controlling a robot, comprising a step of storing a movement amount from the reference teaching position to a point where the robot is stopped and calculating an amount for correcting a deviation amount of the welding torch from the movement amount. 2. The stopping of the robot is performed by applying a sensing voltage to the conductive contact plate and the welding wire and detecting a sensing current flowing when the welding wire and the conductive contact plate come into contact with each other. Robot control method. 3. A predetermined operation pattern for calculating an amount for correcting the deviation amount of the welding torch is defined on the concave portion with the reference teaching position realized by the welding torch having the deviation as the origin of the correction operation. Operation is performed in the positive Y-axis direction until the recess and the welding wire come into contact with each other, and then in the Y-axis negative direction until the recess and the welding wire come into contact with each other. The control method for the robot according to claim 1, wherein the robot is operated until the recess and the welding wire contact each other in the positive direction of the X-axis defined in 1. 4. A controller for the robot, which reproduces the operation of the robot based on pre-stored teaching data of the robot, comprising a jig having a conductive contact plate having a conical recess, and the robot. The welding torch attached to the tip of the wrist is positioned at a predetermined position in the recess, and the storage means that stores the teaching data at that time as the reference teaching position, and the actual tip position due to deformation of the welding torch due to replacement or collision When it deviates from the reference teaching position, the robot is moved to the stored reference teaching position, the robot is operated in a predetermined operation pattern, and the welding wire protruding at the tip of the welding torch and the recess are formed. Correction operation executing means for stopping the robot when the surface of the robot comes into contact with the robot, and the robot is stopped from the reference teaching position. Storing the amount of movement to the point, the robot controller having a correction amount calculating means for calculating an amount for correcting the amount of deviation of the welding torch from the amount of movement. 5. A means for stopping the robot when the welding wire comes into contact with the concave portion, a sensing power source for applying a sensing voltage to the conductive contact plate and the welding wire, and when the welding wire comes into contact with the jig. The robot control apparatus according to claim 4, further comprising a contact detection unit that detects a flowing sensing current. 6. The correction operation executing means for calculating the correction amount of the deviation amount of the welding torch is defined on the jig by using the reference teaching position realized by the welding torch having the deviation as the origin of the correction operation. It is operated until the recess and the welding wire contact in the positive Y-axis direction, and then until the recess and the welding wire contact in the Y-axis negative direction, and then from the origin of the correction operation onto the recess. The robot control apparatus according to claim 4, wherein the robot is operated in a defined Y-axis positive direction until the recess and the welding wire come into contact with each other. 7. When the operation of the robot is reproduced based on pre-stored teaching data of the robot, when the actual tip position deviates from the reference teaching position due to replacement of the welding torch or deformation due to collision, the deviation. A jig for determining the amount, comprising a conductive contact plate having a conical concave portion with which the welding torch operates and contacts with a predetermined operation pattern from a predetermined position, and from the predetermined position to the contact position A jig that can determine the amount of deviation from the amount of movement of the jig.