JPH09185404A - Robot for welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and effectively reduce man-hour for teaching concerning a robot for welding with which a work having various groove angles can be dealt with. SOLUTION: The distance and rotating phase data of non-contact distance sensor 3 and object work 9 are processed into these distance and rotating phase data by a signal processing means 6 and from these distance and rotating phase data, the opening top end angle of object work 9 is detected 7. By calculating the position relation between a manipulator and the object work corresponding to these groove angle data, the work having various groove angles can be easily taught.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to position detection by a sensor of a teaching playback type welding robot.

[0002]

2. Description of the Related Art The automation of welding processes by arc welding robots has been expanding steadily mainly in mass production sites represented by the automobile industry as an effective means for improving productivity and achieving uniform welding quality. It was In addition, a flexible production system using a robot is highly expected as an extremely effective means even for a variety of small-quantity production forms with the diversification of consumer needs in recent years.

However, most of the welding robots currently in operation are so-called teaching playback type robots, and in order to cope with low-volume production of a wide variety of products, one robot is compatible with many production types. While there is a shortage of skilled robot operators while it is necessary to teach operation programs, effective measures for reducing teaching man-hours by simplifying teaching work are desired.

There is a means for effectively reducing the teaching man-hours by replacing the torch tip part of the welding torch held by the manipulator with distance detecting means. And using a non-contact distance sensor as a distance detecting means, the non-contact distance sensor is rotated and scanned at the manipulator tip,
There is a technique (Japanese Patent Laid-Open No. 06-800269) characterized in that a manipulator operates so that the non-contact distance sensor and a target work are at predetermined positions.

In this technique, the non-contact distance sensor is rotated by the rotation scanning means, and the signal data obtained from the distance between the manipulator and the target work and the rotation phase detected by the rotation phase detecting means attached to the rotation scanning means are signaled. Extracted by the processing means, by the position calculating means from the extracted distance and rotational phase data, the positional relationship between the coordinate system fixed to the manipulator tip and the coordinate system set on the target work is calculated, and this is calculated. The operation of the manipulator is stored so that the positional relationship matches the stored predetermined positional relationship. When actually welding, the non-contact distance sensor is replaced with a welding torch, and the manipulator is operated as stored. That is, the manipulator is operated at the target position and posture of the predetermined welding torch with respect to the target work.

The present inventor has proposed a technique of operating the manipulator at a predetermined welding torch target position and posture with respect to various groove-shaped workpieces to be welded. This technique is a means for teaching by teaching the torch tip part of the welding torch held by the manipulator by replacing it with distance detecting means, and disposing a plurality of position calculating means having different calculation methods, and using a non-contact distance sensor as the distance detecting means. The non-contact distance sensor is rotated and scanned, and the position is calculated from the shape of the signal waveform in one rotation scan or the distance and the rotation phase data extracted from the signal processing means and the groove shapes of a plurality of preset target works. The position selecting means suitable for the target work is selected by the method selecting means, the manipulator is stored at the target position and posture of the predetermined welding torch with respect to the target work, and the non-contact distance sensor is welded when actually performing welding. The manipulator is replaced with a torch and the manipulator is operated as memorized.

[0007]

However, in general, the groove angle of the work to be welded is not constant and varies,
Even if the distance to the target work is the same, the distance information extracted from the signal processing means changes depending on the groove angle. That is, the position calculation means that does not consider the groove angle cannot accurately calculate the positional relationship between the manipulator and the target work.

Specifically, when the non-contact distance sensor deviates from the central axis of the non-contact distance sensor while the non-contact distance sensor is following the welding line, the deviation is attempted to be restored. If the groove angle of the target work is narrow, the deviation is recognized as larger than it actually is, and the non-contact distance sensor makes a sudden operation. However, since the actual deviation is narrower than that, the non-contact distance sensor that starts to move suddenly cannot stop and collides with the target work, so that it may not be possible to perform teaching so as to reach a predetermined position. There was a problem.

The present invention solves such a conventional problem, and provides a welding robot which can easily cope with works having various groove angles and can realize a simple and effective teaching man-hour reduction. The purpose is to provide.

[0010]

In order to solve the above-mentioned problems, the present invention provides a groove angle detecting means for detecting a groove angle of a target work, and a gap between a manipulator and the target work based on the groove angle data. A positional relationship calculating means for calculating the positional relationship is provided.

Then, the positional relationship between the manipulator and the target work can be accurately calculated from such groove angle data.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a manipulator for holding a welding torch, a distance detecting means for detecting a distance between the manipulator and a target work, a rotary scanning means for rotationally scanning the distance detecting means, and the rotation. Rotation phase detection means for detecting the rotation phase of the scanning means, and a signal for outputting distance and rotation phase data at the maximum / minimum points of the distance between the manipulator and the target work from the signals from the distance detection means and the rotation phase detection means. A processing means, a groove angle detection means for detecting a groove angle of the target work from the distance and rotation phase data from the signal processing means, and the manipulator to the target work by the data from the signal processing means. Control means for controlling to a predetermined position, and the control based on the groove angle data from the groove angle detecting means. It is obtained by a correction means for correcting the control of the manipulator by stages.

As a judgment criterion of the groove angle calculating means,
Furthermore, a correction can be made more accurately by adding the groove shapes of a plurality of target works stored in the groove shape storage means.

Further, as the correcting means, a plurality of position calculating means for calculating the positional relationship between the manipulator and the target work from the output data of the signal processing means and the groove angle data of the groove angle detecting means, and an appropriate position calculating means. By providing the position calculation method selecting means for selecting, it is possible to prevent erroneous recognition due to a difference in groove angle, and calculate an accurate positional relationship between the manipulator and the target work.

Further, in order to cope with an abnormality, a distance detecting means and an interference judging means for the target work are provided, and a torch coordinate system, an origin on the target work is set with respect to the origin of the tip of the distance detecting means held at the tip of the manipulator. In consideration of the work coordinate system, the positional relationship between the distance detecting means and the target work is calculated, and the distance detecting means and the target work are prevented from interfering with each other, or when they interfere with each other, the interference is avoided. As described above, the manipulator is controlled by the operation control unit, and the correction amount of the position changed so as not to interfere can be stored in the position correction amount storage unit.

The groove shape storage means can manually input and set the groove shapes of a plurality of target works, and the position storage means can manually input and set the positional relationship between the manipulator and the target work.

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) In FIG. 1, reference numeral 1 is a vertical multi-joint type manipulator, and a welding torch (hereinafter referred to as a torch) 2 is attached to the tip thereof. A non-contact distance sensor (hereinafter referred to as a sensor) 3 is used as a distance detecting means and is rotatably attached to the tip of the torch 2 while being eccentric by a predetermined distance d from the central axis of the torch 2. It should be noted that the sensor 3 is adapted to be attached to the torch 2 by removing the torch constituent parts at the tip thereof.

Reference numeral 4 denotes a rotary scanning means, which is attached to the torch 2, uses a motor (not shown) as a rotary drive source, and rotationally scans at a predetermined rotational diameter with the central axis of the torch 2 as the central axis of rotation. Reference numeral 5 denotes a rotation phase detecting means, which is attached to the torch 2, and detects a rotation phase of the sensor 3 by a motor control encoder with a predetermined one direction of the manipulator 1 as a reference position.

Reference numeral 6 denotes a signal processing means, which operates the manipulator 1 based on the detection signals of the sensor 3 and the rotational phase detection means 5.
Then, signal data of the distance and the rotation phase of the target work (hereinafter referred to as the work) 9 is obtained, and the distance and the rotation phase at the maximum / minimum points of the distance between the manipulator 1 and the work 9 are extracted.

The following parts are built in the control means for controlling the manipulator except the work 9.

Reference numeral 7 is a groove angle detecting means, which is a signal processing means 6.
The groove angle of the work 9 is detected based on the distance and the rotation phase data extracted in step. Reference numeral 8 denotes a position calculating means, which is arranged in plural depending on the difference between the output data of the signal processing means 6 and the groove angle data of the groove angle detecting means 7, and calculates the positional relationship between the torch coordinate system and the work coordinate system described later. . Reference numeral 12 is a position calculation method selection means, and the optimum position calculation means 8 is selected based on the output data of the signal processing means 6 and the groove angle data of the groove angle detection means 7. That is, the position calculating means 8 and the position calculating method selecting means 13 are configured as the correcting means.

A position storage means 10 stores a predetermined target position and posture of the torch 2 with respect to the work 9 as a positional relationship between a torch coordinate system and a work coordinate system, which will be described later.
Reference numeral 11 denotes an operation control unit, which has an interference determination unit 21 that determines whether or not the sensor 3 and the work 9 interfere with each other.
The predetermined position data obtained from the position storage means 10 is changed so that the work 9 does not interfere with the work 9 and the difference from the stored position data is stored in the position correction amount storage means (not shown). Further, the manipulator 1 is operated so that the predetermined position data stored in the position storage means 10 and the position data calculated by the position calculation means 8 match.

The operation of the welding robot constructed as above will be described below. First, a torch coordinate system and a work coordinate system, which serve as a reference for the positional relationship between the torch 2 and the work 9, will be described with reference to FIGS. 2 and 3.

FIG. 2 shows a torch coordinate system set on the torch 2 attached to the manipulator 1. In the torch coordinate system, the action point at the tip of the torch 2 is the coordinate origin Ot of the torch coordinate system, and the central axis of the torch 2 is the Xt axis. The positive direction of the Xt axis is indicated by an arrow in FIG. 2 (the positive direction of each coordinate axis described below is indicated by an arrow in the figure). A direction orthogonal to the Xt axis on a plane including the Xt axis and the rotation center axis TW of the most advanced wrist axis of the manipulator 1 is defined as a Zt axis. And X
The remaining axis that is orthogonal to the t-axis and the Zt-axis and forms a right-handed coordinate system is the Yt-axis.

FIG. 3 shows a work coordinate system set on the work 9. In the state where the manipulator 1 is positioned in the vicinity of the welding line on the work 9, the point where the Xt axis of the torch coordinate system is extended and intersects with the work 9 is designated as Q, and the perpendicular line and the welding line dropped from the point Q to the welding line. The intersection is defined as the coordinate origin Ow of the work coordinate system. The direction of the welding line from this coordinate origin Ow is Y
Xw is the direction that divides the groove angle of the workpiece 9 into two equal parts with the w axis.
Axis. Further, the remaining axis that is orthogonal to the Xw axis and the Yw axis and forms the right-handed coordinate system is the Zw axis. Since the Xw axis and the Zw axis are located on the other side of the work 9, they are indicated by dotted lines.

Both the torch coordinate system and the work coordinate system are right-handed coordinate systems, and if the positive direction of each axis is the right-handed coordinate system, the directions shown in FIGS. No need to fix.

FIG. 4 is a block diagram showing a data flow according to the first embodiment of the present invention. The distance detected by the sensor 3 and the rotation phase obtained from the rotation phase detection means 5 are input to the signal processing means 6, and the manipulator 1 is operated.
Is processed into distance and rotation phase data at maximum / minimum points of the distance between the workpiece 9 and the workpiece 9, and is input to the phase calculation method selection means 12, the position calculation means 8 and the groove angle detection means 7.

The position calculation method selection means 12 is the signal processing means 6
Based on the output data of 1 and the groove angle of the work 9 detected by the groove angle detecting means 7, a suitable position calculating means 8 is selected. The selected position calculating means 8 determines the positional relationship between the torch coordinate system and the work coordinate system according to the distance and the rotation phase extracted by the signal processing means 6 and the groove angle of the workpiece 9 detected by the groove angle detecting means 7. To calculate.

The position data calculated by the position calculation means 8 is input to the operation control means 11 together with the predetermined position data stored in the position storage means 10, and the calculated position data matches the predetermined position data. The manipulator 1 is operated as described above. At this time, the interference determination means 21 operates the sensor 3 so as not to interfere with the work 9.

Next, the specific calculation of the positional relationship between the torch coordinate system and the work coordinate system by the position calculating means 8 will be described with reference to the drawings.

First, FIG. 5 shows a schematic view in the case where the work 9 has a T-shaped joint groove shape (a groove angle of 90 degrees) and the torch coordinate system and the work coordinate system coincide with each other. In FIG. 5, the sensor 3 is rotated counterclockwise about the Xt axis by the rotary scanning means 4 (not shown) while continuing the distance in the Xt axis direction (the length of the arrow in the figure) to the work 9. Will be detected. Depending on the sensor, the arrow may not be in a fixed direction as shown in FIG. 5, but here, the arrow merely indicates that the distance in the arrow direction is detected.
This will be described below. During the detection, the rotational phase of the sensor 3 is simultaneously detected by the rotational phase detecting means 5, and the signal data as shown in FIG. 6 is obtained.

The vertical axis of FIG. 6 indicates the workpiece 9 measured by the sensor 3.
And the horizontal axis is the rotation phase of the sensor 3 obtained by the rotation phase detecting means 5. Since this signal data changes according to the positional relationship between the torch coordinate system and the work coordinate system, the positional relationship between the torch coordinate system and the work coordinate system can be known by detecting the change in this signal data.

Here, regarding the maximum and minimum points of the distance,
As is clear from FIG. 5, the maximum points are located before and after the welding line of the work 9, and these characteristic points are designated as F and B. The minimum point is located at a position where the left and right surfaces of the work 9 intersect the Xt-Zt plane, and the left and right characteristic points are L and R. The signal processing unit 6 extracts the distance and the rotation phase for each of the characteristic points F, B, L, and R from the distance measured by the sensor 3 and the phase of the rotation phase detection unit 5.

FIG. 7 shows the case where the groove angle of the work 9 is 60 degrees. The signal data obtained at this time is shown in FIG. 8, and the maximum and minimum points are designated as F1, B1, L1, and R1. Further, the broken line in FIG. 8 is a signal when the groove angle is 90 degrees in which the torch coordinate system and the work coordinate system shown in FIG. 7 coincide.

As is apparent from FIG. 8, when the groove angle changes, the difference between the average value of the distances F1 and B1 and the average value of the distances L1 and R1 changes. Therefore, use this difference value. Thus, the groove angle can be detected. 7 and 8
If the average value of the distance between F1 and B1 and the average value of L1 and R1 are La and Lb, respectively, the difference L is (Equation 1)
Is calculated by

[0036]

[Equation 1]

Let r be the radius of gyration of the sensor 3 at L,
When the groove angle is θ, (Equation 2) is established from a right-angled triangle defined by L, r, and θ / 2.

[0038]

[Equation 2]

Therefore, the groove angle θ to be obtained is represented by (Equation 3).

[0040]

(Equation 3)

FIG. 9 shows a work 9 having a groove angle of 60 degrees and Zt.
The case where a shift Z0 occurs in the direction is shown. The signal data obtained at this time is shown in FIG. The maximum and minimum points at this time are defined as F2, B2, L2, and R2. Further, the broken line in FIG. 10 shifts in the Zt direction in the work 9 having a groove angle of 90 degrees Z
This is signal data obtained when 0 is generated. The maximum and minimum points at this time are defined as Fz, Bz, Lz, and Rz.

Conventionally, the shift in the Zt direction can be calculated from the difference in the distance between Lz and Rz. However, when the groove angles are different, if the same calculation method is used, the same Z0 shift will be obtained. This is the result of calculating the shift amount. For example,
The deviation Z0 when the groove angle is 90 degrees is represented by (Equation 4) as the distance difference between LZ and RZ, but when the groove angle is 60 degrees, the deviation Z0 is represented by (Equation 5).

[0043]

(Equation 4)

[0044]

(Equation 5)

Therefore, by correcting the difference in distance by using the angle detected by the groove angle detecting means 7, even in the works 9 having different groove angles, the same deviation amount Z can be obtained.
The same calculated value Z0 for 0 can be obtained.

Next, the interference determination means 21 of the operation control means 11
The interference between the sensor 3 and the work 9 in 1 will be described.

FIG. 11 is a view showing interference between the work 9 having the groove angle data and the sensor 3 having the rotational scanning diameter φ.

As can be considered from FIG. 11, presence / absence of interference between the sensor 3 and the work 9 is determined by the known rotational scanning diameter, the position data stored by the position storage means 10, and the opening angle detected by the groove angle detection means 7. Based on the tip angle data, it can be determined in the same manner as the above-described calculation of the shift amount. At the same time, it is possible to calculate the minimum correction amount of the position required to avoid interference.

The interference determination means 21 for determining the interference between the sensor 3 and the work 9 and the method for calculating the position correction amount need not be provided as the features of the operation control means 11, and the interference determination means 2
The same effect can be obtained even if it is provided with a feature that the position correction amount calculation means necessary to avoid interference with 1 is newly provided.

The operation control means 11 stores the correction amount of the position required for avoiding interference in the position correction amount storage means (not shown). When actually welding, the sensor 3 is removed from the tip of the welding torch, and the torch structure is formed. The manipulator 1 is controlled by replacing it with a component and correcting the correction amount to a set position.
When the position data of the manipulator 1 at the stored position is necessary, it is easy to correct the position data of the manipulator 1 based on the correction amount stored in the position correction amount storage means (not shown). Obtainable.

As described above, by considering the groove angle data, the positional relationship with the manipulator can be accurately calculated even for works with various groove angles.

Further, by providing the interference determining means 21, it is possible to prevent the interference between the sensor 3 and the work 9 and to teach that the sensor 3 and the work 9 do not interfere with each other.

(Embodiment 2) In FIG. 12, the same symbols as those in FIG.

In FIG. 12, reference numeral 1 is a vertical articulated manipulator, and a welding torch (hereinafter referred to as a torch) 2 is attached to the tip of the manipulator. A non-contact distance sensor (hereinafter referred to as a sensor) 3 is used as a distance detecting means and is rotatably attached to the tip of the torch 2 while being eccentric by a predetermined distance d from the central axis of the torch 2. The sensor 3 is designed to be attached to the tip of the torch 2 by removing it.

Reference numeral 4 denotes a rotary scanning means, which is attached to the torch 2, uses a motor (not shown) as a rotary drive source, and rotationally scans at a predetermined rotational diameter with the central axis of the torch 2 as the central axis of rotation. Reference numeral 5 denotes a rotation phase detecting means, which is attached to the torch 2, and detects a rotation phase of the sensor 3 by a motor control encoder with a predetermined one direction of the manipulator 1 as a reference position.

Reference numeral 6 denotes a signal processing means, which operates the manipulator 1 based on the detection signals of the sensor 3 and the rotational phase detection means 5.
Then, signal data of the distance and the rotation phase of the target work (hereinafter referred to as the work) 9 is obtained, and the distance and the rotation phase at the maximum / minimum points of the distance between the manipulator 1 and the work 9 are extracted.

The following parts are built in the control means for controlling the manipulator except the work 9.

Reference numeral 13 denotes a groove shape memory means, which stores various groove shapes such as a corner joint and a T-shaped joint. Reference numeral 20 is a groove angle detecting means for detecting the groove angle of the work 9 from the distance and the rotation phase data extracted by the signal processing means 6.
Reference numeral 8 denotes a position calculating means, which is arranged in plural depending on the difference between the output data of the signal processing means 6, the groove shape of the groove shape detecting means 13 and the groove angle data of the groove angle detecting means 20,
Calculate the positional relationship between the torch coordinate system and the work coordinate system. 1
Reference numeral 2 denotes a position calculation method selection means, which selects the optimum position calculation means 8 based on the output data of the signal processing means 6, the groove shape data of the groove shape storage means 13 and the groove angle data of the groove angle detection means 20. To be done. That is, the position calculating means 8 and the position calculating method selecting means 13 are configured as the correcting means.

A position storage means 10 stores a predetermined target position and posture of the torch 2 with respect to the work 9 as a positional relationship between the torch coordinate system and the work coordinate system. Reference numeral 11 denotes an operation control means, and the interference determination means 21 determines whether or not the sensor 3 and the work 9 interfere with each other, and changes a predetermined position obtained from the position storage means 10 so that the sensor 3 and the work 9 do not interfere with each other. At the same time, the difference from the stored position is stored in the position correction amount storage means (not shown). Further, the manipulator 1 is operated so that the predetermined position stored in the position storage means 10 and the position calculated by the position calculation means 8 match.

The operation of the welding robot constructed as described above will be described. First, the torch coordinate system and the work coordinate system, which serve as the reference for the positional relationship between the torch 2 and the work 9, are the same as those described in the first embodiment with reference to FIGS.

FIG. 13 is a block diagram showing a data flow according to the second embodiment of the present invention. The distance detected by the sensor 3 and the rotation phase data obtained from the rotation phase detecting means 5 are input to the signal processing means 6 and processed into the distance and the rotation phase at the maximum / minimum points of the distance between the manipulator 1 and the work 9. Then, it is input to the position calculation method selection means 12, the position calculation means 8, the groove shape storage means 13, and the groove angle detection means 20.

The position calculation method selection means 12 is the signal processing means 6
A suitable position calculating means 8 is selected on the basis of the output data of 1), the groove shape stored in the groove shape storage means 13, and the groove angle of the workpiece 9 detected by the groove angle detecting means 20. The selected position calculating means 8 opens the work 9 detected by the groove shape and the groove angle detecting means 20 of the work 9 stored in the groove shape storing means 13, the distance and the rotation phase extracted by the signal processing means 6. The positional relationship between the torch coordinate system and the work coordinate system is calculated from the tip angle.

The position calculated by the position calculation means 8 is input to the operation control means 11 together with the desired position stored in the position storage means 10 so that the calculated position data matches the predetermined position data. The manipulator 1 is operated. At this time, the interference determination means 21 operates the sensor 3 so as not to interfere with the work 9.

Next, the specific calculation of the positional relationship between the torch coordinate system and the work coordinate system by the position calculating means 8 is the same as that described in the first embodiment with reference to FIGS. 5 to 10. The description here is omitted.

Further, the interference determination means 2 of the operation control means 11
The interference between the sensor 3 and the workpiece 9 in 1 is also the same as that described in the first embodiment with reference to FIG. 11, and thus the description thereof is omitted here.

As described above, the positional relationship with the manipulator can be accurately calculated even for works with various groove angles by using the groove angle data in which the groove shape of the work 9 is taken into consideration.

By providing the interference determining means 21, it is possible to teach that the sensor 3 and the work 9 are prevented from interfering with each other and that the sensor 3 and the work 9 do not interfere with each other.

Although the non-contact distance sensor capable of detecting continuous point data is used as the distance detecting means in the present embodiment, discontinuous point data such as a laser sensor can be processed in the same manner.

Also, the distance detecting means has been described as a means for exchanging one part of the welding torch, but a means for exchanging the complete welding torch may be used.

This has the effect that the distance detecting means can be selected over a wide range.

[0071]

As described above, according to the present invention, the distance detecting means is attached to a part of the welding torch held by the manipulator or is attached instead of the welding torch, and the distance detecting means is rotationally scanned. A means for controlling the manipulator to a predetermined position of the target work from the distance and rotation phase data between the manipulator and the target work extracted by the signal processing means from the continuous point signal or the discontinuous point signal data in the rotary scanning. Provided with a correcting means for easily controlling the groove angle of the target work by the groove angle detecting means from the distance and the rotation phase data, and correcting the control of the manipulator by the control means from the detected groove angle. Therefore, it is possible to easily deal with the groove angles of a plurality of target works.

Further, since the interference between the distance detecting means and the target work can be checked from the groove angle detected by the groove angle detecting means, the interference between the distance detecting means and the target work can be prevented. If the distance detection means and the target work interfere with each other, it is possible to operate while avoiding the interference by correcting the position, and by correcting the position of the robot by the correction amount of the corrected position, It is possible to easily obtain the position of the robot while maintaining the predetermined position, and it is possible to prevent a decrease in work efficiency and an increase in work man-hours due to interference with the target work.

[Brief description of the drawings]

FIG. 1 is an external view showing an overall configuration of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a first coordinate system.

FIG. 3 is an explanatory diagram of a second coordinate system.

FIG. 4 is a block diagram showing the first embodiment of the present invention.

FIG. 5 is a schematic diagram when the torch coordinate system and the workpiece coordinate system match for a workpiece with a groove angle of 90 degrees.

FIG. 6 is a signal waveform diagram when the torch coordinate system and the workpiece coordinate system match for a workpiece with a groove angle of 90 degrees.

FIG. 7 is a schematic diagram when the torch coordinate system and the workpiece coordinate system match for a workpiece with a groove angle of 60 degrees.

FIG. 8 is a signal waveform diagram when the torch coordinate system and the workpiece coordinate system match for a workpiece with a groove angle of 60 degrees.

FIG. 9 is a schematic diagram when the torch coordinate system and the workpiece coordinate system are deviated in the Zt direction in a workpiece with a groove angle of 60 degrees.

FIG. 10 is a signal waveform diagram when the torch coordinate system and the work coordinate system are deviated in the Zt direction in a work with a groove angle of 60 degrees.

FIG. 11 is a diagram showing interference between a workpiece having a groove angle θ and a non-contact distance sensor.

FIG. 12 is an external view showing the overall configuration of the second embodiment of the present invention.

FIG. 13 is a block diagram showing a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Manipulator 2 Welding torch 3 Distance detection means (non-contact distance sensor) 4 Rotation scanning means 5 Rotation phase detection means 6 Signal processing means 7 Groove angle detection means 8 Position calculation means 9 Target work piece 10 Position storage means 11 Operation control means 12 Position calculation method selection means 13 Groove shape storage means 20 Groove angle calculation means 21 Interference determination means

Claims (8)

[Claims] 1. A manipulator for holding a welding torch, a distance detecting means for detecting a distance between the manipulator and a target work, a rotary scanning means for rotationally scanning the distance detecting means, and a rotational phase of the rotary scanning means. Rotation phase detection means for detecting, signal processing means for outputting rotation phase data and distance at the maximum / minimum point of the distance between the manipulator and the target work from the signals from the distance detection means and the rotation phase detection means, and the signal The groove angle detection means for detecting the groove angle of the target work from the distance and the rotation phase data from the processing means, and the data from the signal processing means to position the manipulator at a predetermined position with respect to the target work. Motion control means for controlling
A welding robot comprising: a correction unit that corrects the control of the manipulator by the operation control unit based on the groove angle data from the groove angle detection unit. 2. The groove angle detecting means detects the groove angle of the target work from the data of the groove shape storing means that stores the groove shapes of a plurality of target works, the distance of the signal processing means, and the rotation phase data. The welding robot according to claim 1, wherein 3. The correction means is the same as the plurality of position calculation means for calculating the positional relationship between the manipulator and the target work from the output data of the signal processing means and the groove angle data of the groove angle detection means. The welding robot according to claim 1 or 2, further comprising: a position calculation method selection unit that selects an appropriate position calculation unit according to the input data. 4. A torch coordinate system having a working point of a tip of a welding torch held at a tip of a manipulator as an origin and having a central axis of the welding torch as a coordinate axis, the manipulator being near a welding line on a target work. In the positioned state, the extension line of the coordinate axis of the torch coordinate system has a work coordinate system whose origin is an intersection of a perpendicular and a welding line drawn from a point intersecting the target work to a welding line, and the manipulator. A position storage unit for storing the position of the target work is provided, and whether or not the distance detection unit and the target work interfere with each other based on the groove angle detected by the groove angle detection unit and the position stored in the position storage unit. The welding robot according to any one of claims 1 to 3, further comprising: an interference determination unit that determines whether the welding robot is used. 5. The welding according to claim 4, wherein when the interference determination means determines that the distance detection means and the target work may interfere with each other, the manipulator is controlled by the operation control means so as to avoid the interference. Robot. 6. The welding robot according to claim 5, further comprising position correction amount storage means for storing the correction amount of the position changed so as not to interfere. 7. The welding robot according to claim 2, wherein the groove shape storage means is capable of manually inputting and setting the shapes of a plurality of target works. 8. The position storage means is capable of manually inputting and setting the positional relationship between the manipulator and the target work.
The welding robot according to any one of claims 1 to 7.