JP2022047209A - Welding position detection device - Google Patents

Abstract

To provide a welding position detection device that can reduce the wrong detection of a welding position even if a work is tilted.SOLUTION: The welding position detection device according to the present invention includes a search unit 110 and a tilt calculation unit 120. The search unit 110 moves a contact sensor 22 to acquire a first distance dv1 from a first position P1 to a first work W10 or a first coordinate value of a contact point with the work W10, and acquires a second distance dv2 from a second position P2 that is a predetermined distance dh0 from the first position P1 to the first work W10, or a second coordinate value of the contact point with the work W10. The tilt calculation unit 120 calculates a tilt α of the first work W10 on the basis of the first distance dv1, the predetermined distance dh0, and the second distance dv2, or the first coordinate value and the second coordinate value. The search unit 110 moves the contact sensor 22 along the tilt α and detects a second work W20.SELECTED DRAWING: Figure 4

Description

The present invention relates to a welding position detecting device.

A welding robot that performs arc welding generally moves a welding torch along a welding line position preset by teaching to weld a workpiece to be joined. When welding is performed by a welding robot, for example, due to an assembly error of the work to be welded and deformation of the work due to heat during welding, there is a deviation between the welding line position set in the welding robot and the welding position of the work to be welded. May occur.

In order to correct such a positional deviation, a method for generating a sensing motion of a working manipulator provided with a contact sensor has been proposed (see, for example, Patent Document 1).

Specifically, in the sensing operation generation method of the work manipulator described in Patent Document 1, the contact surface of the work to which the contact sensor contacts is extracted, and one edge constituting the contact surface is selected. Then, the sensing posture of the work manipulator is reset so that the position of the edge coincides with the position where the set position set on the base end side of the contact sensor is projected onto the contact surface.

Japanese Unexamined Patent Publication No. 2011-170522

However, in the method of generating the sensing motion of the work manipulator described in Patent Document 1, although the contact sensor can cope with the parallel deviation such as deep hitting or shallow hitting the work, it corresponds to the erroneous detection due to the inclination of the work. There is a problem that it cannot be done.

Therefore, an object of the present invention is to provide a welding position detecting device capable of reducing erroneous detection of a welding position even when the work is tilted.

The welding position detecting device according to one aspect of the present invention is a welding position detecting device that detects a welding position using a contact type sensor, and moves the contact type sensor from the first position to the first direction to make the contact. The first search unit that acquires the first coordinate value at the first distance or the contact point from the first position to the first work by bringing the formula sensor into contact with the first work to be welded, and the first By moving the contact sensor from the second position located at a predetermined distance in the second direction perpendicular to the first direction from the first position to the first direction, the contact sensor and the first work are brought into contact with each other. , Based on the first distance, the predetermined distance and the second distance, or the first with the second search unit that acquires the second coordinate value at the second distance from the second position to the first work or the contact point. The inclination calculation unit that calculates the inclination of the first work based on the coordinate values and the second coordinate value, and the second work that is joined to the first work by moving the contact sensor along the inclination of the first work. It is provided with a third search unit for acquiring the distance to.

According to this aspect, the first search unit acquires the first coordinate value at the first distance from the first position to the first work or the contact point with the first work, and the second search unit obtains the first position. The second coordinate value at the second distance from the second position located at a predetermined distance to the first work or the contact point with the first work is acquired. Then, the inclination calculation unit calculates the inclination of the first work based on the first distance, the predetermined distance and the second distance, or based on the first coordinate value and the second coordinate value, and the third search unit calculates the inclination of the first work. The second work is searched by moving the contact sensor along the inclination of the first work. Therefore, the contact type sensor can avoid erroneous detection of contact with the first work and missed swing that the second work cannot be detected. That is, even when the work is tilted, it is possible to reduce erroneous detection of the welding position.

In the above aspect, the second direction may be a direction away from the second work.

According to this aspect, since the second position is located in a direction away from the first position with respect to the second work, unintended contact with the second work when the contact sensor is moved to the second position. Can be avoided. Since the inclination of the first work in the direction away from (approaching) the welding line position between the first work and the second work can be calculated, the contact sensor can detect erroneous contact with the first work. And it is possible to surely avoid the missed swing that the second work cannot be detected.

In the above aspect, the first direction may be a vertical direction or a horizontal direction.

According to this aspect, the first search unit and the second search unit search the first work twice in the vertical direction or twice in the horizontal direction, and the tilt calculation unit tilts or faces the first work with respect to the horizontal plane. The inclination of the first work with respect to is calculated. Then, the third search unit searches for the second work by moving the contact sensor along the inclination of the first work with respect to the horizontal plane or the inclination of the first work with respect to the vertical plane. Therefore, regardless of whether the first work is tilted with respect to the horizontal plane or the vertical plane, the second work is appropriately detected and erroneous detection of the welding position is reduced. can do.

In the above aspect, the first search unit may retract the contact sensor in the direction opposite to the first direction after the contact sensor and the first work are brought into contact with each other.

According to this aspect, since the welding wire or the like which is the tip of the contact type sensor is retracted in the direction opposite to the first direction in contact with the first work, the load on the welding wire or the like due to the contact is reduced and the welding is performed. It is possible to prevent the wire or the like from bending.

In the above aspect, the first search unit may be retracted by at least the first distance.

According to this aspect, since the contact sensor is separated from the first work by a sufficient distance, even if the first work is tilted to a considerable extent, when the contact sensor is moved to the second position, the contact sensor is moved to the second position. It is possible to avoid unintended contact with the first work.

In the above embodiment, the second search unit contacts the contact sensor and the first work, and then, based on the inclination of the first work calculated by the inclination calculation unit, the second search unit is perpendicular to the first work. The contact type sensor may be retracted.

According to this aspect, since the welding wire or the like which is the tip of the contact type sensor is retracted in the direction perpendicular to the first work, the load on the welding wire or the like due to the contact is reduced and the welding wire or the like is bent. It can be prevented from doing so.

According to the present invention, it is possible to provide a welding position detecting device capable of improving the welding position detection accuracy even when the work is tilted.

It is a system schematic diagram which shows the welding robot system 10 which concerns on 1st Embodiment of this invention. It is a functional block diagram which shows each function of the welding position detection apparatus 100 which concerns on 1st Embodiment of this invention. It is a flowchart which shows the welding position detection method 300 executed by the welding position detection apparatus 100 which concerns on 1st Embodiment of this invention. It is a figure which shows the mode that the 1st work and the 2nd work are searched by the contact type sensor in the welding position detection apparatus 100 which concerns on 1st Embodiment of this invention. It is a figure which shows a mode that the inclination calculation unit 120 calculates the inclination of the 1st work based on the coordinate value in the welding position detection apparatus 100 which concerns on 1st Embodiment of this invention. It is a flowchart which shows the welding position detection method 500 executed by the welding position detection apparatus 100 which concerns on 2nd Embodiment of this invention. It is a figure which shows the mode that the 1st work and the 2nd work are searched by the contact type sensor in the welding position detection apparatus 100 which concerns on 2nd Embodiment of this invention.

Hereinafter, each embodiment of the present invention will be specifically described with reference to the accompanying drawings. It should be noted that each embodiment described below is merely a specific example for carrying out the present invention, and does not limit the interpretation of the present invention. Further, in order to facilitate understanding of the description, the same components are designated by the same reference numerals as possible in each drawing, and duplicate description is omitted.

<First Embodiment>
[Overview of welding robot system]
FIG. 1 is a system schematic diagram showing a welding robot system 10 according to the first embodiment of the present invention. In FIG. 1, the welding robot system 10 includes a welding robot 20, a teach pendant 30, a robot control device 40, and a power supply 50.

The welding robot 20 is connected to the robot control device 40 via a cable, and performs arc welding based on an operation command from the robot control device 40. The welding robot 20 is provided with a welding torch 21 at the tip of the arm, and by feeding a welding wire from the tip of the welding torch 21 and generating an arc with a metal material (work) to be welded. Perform arc welding.

The welding torch 21 is connected to the power source 50 via a cable, and receives a welding voltage and a welding current supplied to the welding wire. In arc welding, when the welding wire is momentarily brought into contact with the metal material and energized, an arc discharge is generated between the welding wire and the metal material, and the heat of the generated arc melts the welding wire and the metal material. By doing so, welding is performed.

The teach pendant 30 receives input from a worker who performs welding work about welding-related teaching information of the welding robot 20. The operator inputs the optimum welding-related teaching information using the teach pendant 30 while checking the state of the arc.

Here, the welding-related teaching information is information about welding performed by the welding robot 20, and includes teaching information and welding conditions for teaching the operation of the welding robot 20. The teaching information of the welding robot 20 includes information on the operation of the arm of the welding robot 20, information on the position and posture of the welding robot 20, information on the protrusion length of the welding wire supplied from the tip of the welding torch 21, and the like. .. Further, the welding conditions include the welding voltage applied to the welding wire, the value of the welding current flowing through the welding wire, the welding speed indicating the moving speed of the welding torch 21 in the direction of the welding line during welding, and the like.

The robot control device 40 is a device that controls the welding robot 20. The robot control device 40 is connected to the teach pendant 30, and can acquire welding-related teaching information input to the teach pendant 30. The robot control device 40 controls the welding robot 20 and the power supply 50 based on the welding-related teaching information.

The power supply 50 is connected to the welding robot 20 via a cable, and supplies a welding voltage and a welding current to the welding torch 21 in the welding robot 20 based on a command from the robot control device 40.

Although the teach pendant 30 is connected to the robot control device 40 via a cable in FIG. 1, it may be connected wirelessly. That is, the teach pendant 30 and the robot control device 40 may include a communication unit that performs wireless communication. By wirelessly connecting the robot control device 40 and the teach pendant 30, the operator can move freely without being bothered by the existence of the cable or being restricted by the length of the cable. While it is possible to input welding-related teaching information.

[Structure of welding position detection device]
In the above-mentioned welding robot system 10, when the welding robot 20 performs arc welding on a work, the welding position on the work is important. Hereinafter, the configuration of the welding position detection device that detects the welding position using the contact type sensor will be described in detail. In the welding position detection device, the position of the work is confirmed by contacting the work using a contact sensor, and the welding position in the work is detected.

FIG. 2 is a functional block diagram showing each function of the welding position detecting device 100 according to the first embodiment of the present invention. In FIG. 2, the welding robot 20 includes a contact sensor 22, and the robot control device 40 includes a welding position detection device 100. The welding position detection device 100 includes a search unit 110 including a contact detection unit 111 and a voltage application command unit 112, an inclination calculation unit 120, and a control unit 130.

Although the welding position detecting device 100 is configured to be included in the robot control device 40, it can be interpreted that the welding position detecting device 100 is included as a function and a software configuration provided in the welding position detecting device 100. In other words, the robot control device 40 may be configured to include each functional block provided in the welding position detecting device 100.

The contact type sensor 22 in the welding robot 20 may typically use a wire touch sensor. In a state where a sensing voltage is applied between the welding wire protruding from the tip of the welding torch 21 in the welding robot 20 and the work to be welded, the welding torch 21 in the welding robot 20 is subjected to an operation command of the control unit 130. Move. When the welding wire protruding from the tip of the welding torch 21 comes into contact with the work, the voltage changes at that time, and the contact between the welding wire and the work is recognized by the change in the voltage. That is, the welding torch 21 and the welding wire protruding from the tip of the welding torch 21 bear one end of the contact type sensor 22.

The search unit 110 moves the contact sensor 22 to acquire the coordinate value at the distance until the welding wire and the work come into contact with each other or the contact point with the work. Specifically, the voltage application command unit 112 commands the power supply 50 to apply a voltage for sensing between the welding wire and the work, and in a state where the voltage is applied, an operation command of the control unit 130. Moves the welding torch 21 in the welding robot 20. The contact detection unit 111 monitors the voltage and detects the contact between the welding wire and the work by the change of the voltage. In this way, the search unit 110 acquires the moving distance of the welding torch 21 (welding wire) or the coordinate value at the contact point by detecting the contact between the welding wire and the work.

The inclination calculation unit 120 calculates the inclination of the work based on the distance to the work acquired by the search unit 110 or the coordinate value at the contact point with the work. The details of the inclination calculation method will be described later.

The control unit 130 sends and receives commands and data to the search unit 110 and the inclination calculation unit 120, controls the processing executed by the welding position detection device 100, and stores them in a storage unit (not shown) such as a memory. The welding robot 20 and the power supply 50 are controlled based on the welding-related teaching information provided.

[Welding position detection method when the work is tilted]
Next, when the work is tilted, a welding position detection method for detecting the welding position while calculating the tilt of the work will be specifically described.

FIG. 3 is a flowchart showing a welding position detection method 300 executed by the welding position detection device 100 according to the first embodiment of the present invention, and FIG. 4 is a flowchart showing the welding position detection device 100 according to the first embodiment of the present invention. It is a figure which shows the mode that the 1st work and the 2nd work are searched by the contact type sensor. Hereinafter, (1) to (6) shown in the specification correspond to the circled numbers 1 to 6 shown in FIG.

In FIG. 3, the welding position detecting method 300 includes steps S301 to S310, and each step is executed by a processor included in the welding position detecting device 100. Further, here, as shown in FIG. 4, a case where the first work W10 and the second work W20 are vertically overlapped and welded, and a so-called lap joint will be described as an example.

In step S301, the search unit 110 searches the first work W10 by moving the contact sensor 22 (welding torch 21) in the vertical direction from the first position P1 (1).

In step S302, the contact detection unit 111 in the search unit 110 detects the contact between the contact type sensor 22 (welding wire protruding from the tip of the welding torch 21) and the first work W10. As a result, the search unit 110 acquires the first distance dv1 from the first position P1 to the first work W10 based on the moving distance of the contact sensor 22.

Steps S301 and S302 are first searches for searching the first work W10 in the vertical direction from the first position P1 and acquiring the first distance dv1.

In step S303, the search unit 110 moves the contact sensor 22 by the first distance dv1 in the direction opposite to the search direction in step S301 (2). More specifically, the search unit 110 moves the contact sensor 22 moved in steps S301 and S302 by the first distance dv1 in the direction opposite to the search direction, and moves the contact sensor 22 to the first position P1. return. The search direction is a vertical direction and a direction approaching the first work W10, and a direction opposite to the search direction is a vertical direction and a direction away from the first work W10.

Here, as a post-processing of the first search, the search unit 110 brings the contact sensor 22 into contact with the first work W10, and then retracts the contact sensor 22 in the direction opposite to the search direction. Actually, it is the welding wire protruding from the tip of the welding torch 21 that comes into contact with the first work W10, and the welding wire may be burdened by the contact. Therefore, after the contact is made, the welding wire or the like is retracted in the direction opposite to the contact search direction to reduce the load on the welding wire or the like due to the contact and prevent the welding wire or the like from bending.

Further, the search unit 110 moves the contact sensor 22 by the first distance dv1 and returns it to the first position P1. If the first work W10 is tilted to a considerable extent, if the contact sensor 22 is moved in the horizontal direction in the next step S304, unintended contact may occur with the first work W10. A sufficient distance is secured for the work W10. The first position P1 is set as a search start position at a position where a sufficient distance is secured with respect to the first work W10 so that unintended contact with the first work W10 does not occur.

In other words, the search unit 110 does not have to return the contact sensor 22 to the first position P1 and moves a distance larger than the first distance dv1 to secure a sufficient distance with respect to the first work W10. It doesn't matter. Further, if it is possible to avoid unintended contact with the first work W10 when the contact sensor 22 is moved in the horizontal direction, the contact sensor 22 may be moved by a distance smaller than the first distance dv1. I do not care.

In step S304, the search unit 110 moves the contact sensor 22 to the second position P2, which is separated by a predetermined distance dh0 in the horizontal direction (3).

Here, the search unit 110 is supposed to move the contact type sensor 22 in the horizontal direction, but this is a direction away from (approaching direction) to the second work W20, and typically, the first work W10. It is a direction away from (a direction toward approaching) the welding line position between the second work W20 and the second work W20. By locating the first position P1 and the second position P2 in a direction away from (approaching) the welding line position, the inclination of the first work W10 with respect to the direction can be calculated. As a result, the contact type sensor 22 can surely avoid erroneous detection of contact with the first work and missed swing that the second work cannot be detected.

Further, if the search unit 110 moves the contact sensor 22 in a direction approaching the second work W20, an unintended contact may occur with the second work W20. Therefore, the search unit 110 is closer to the second work W20. It is more preferable to move the sensor away from it.

In step S305, the search unit 110 moves the contact sensor 22 in the vertical direction again from the second position P2 to search for the first work W10 (4).

In step S306, the contact detection unit 111 in the search unit 110 detects the contact between the contact type sensor 22 (welding wire protruding from the tip of the welding torch 21) and the first work W10. As a result, the search unit 110 acquires the second distance dv2 from the second position P2 to the first work W10 based on the moving distance of the contact sensor 22.

Steps S305 and S306 are second searches for searching the first work W10 in the vertical direction from the second position P2 and acquiring the second distance dv2.

In step S307, the inclination calculation unit 120 calculates the inclination α of the first work W10 based on the first distance dv1, the predetermined distance dh0, and the second distance dv2. Here, it can be calculated by the slope α = (first distance dv1-second distance dv2) / predetermined distance dh0.

In step S308, after the contact sensor 22 and the first work W10 are brought into contact with each other, the search unit 110 attaches to the first work W10 based on the inclination α of the first work W10 calculated by the inclination calculation unit 120. On the other hand, the contact sensor 22 is moved in the vertical direction by a distance d1 (5).

Here, as a post-processing of the second search, the search unit 110 brings the contact sensor 22 into contact with the first work W10, and then retracts the contact sensor 22 in the direction perpendicular to the first work W10. ing. Actually, it is the welding wire protruding from the tip of the welding torch 21 that comes into contact with the first work W10, and the welding wire may be burdened by the contact. Therefore, by retracting the work W10 in the vertical direction after contacting the work, the load on the welding wire or the like due to the contact is reduced, and the welding wire or the like is prevented from bending.

Further, the search unit 110 moves the contact sensor 22 by a distance d1. Here, if the distance d1 is too small, if there are measurement errors, calculation errors, irregularities on the surface of the first work W10, etc., the first work W10 will move when the contact sensor 22 moves in step S309 described later. There is a possibility of accidental contact with. On the other hand, if the distance d1 is too large, the contact sensor 22 cannot come into contact with the second work W20 in step S310 described later, and there is a possibility that the contact sensor 22 will miss the second work W20. Therefore, here, the distance d1 may be set to about half the thickness of the second work W20.

In step S309, the search unit 110 searches the second work W20 by moving the contact sensor 22 along the inclination α of the first work W10 calculated by the inclination calculation unit 120 in step S307 (6).

In step S310, the contact detection unit 111 in the search unit 110 detects the contact between the contact sensor 22 (welding wire protruding from the tip of the welding torch 21) and the second work W20. As a result, the search unit 110 acquires the distance to the second work W20 based on the moving distance of the contact sensor 22. This is a third search for searching the second work W20 along the inclination α of the first work W10 and acquiring the distance to the second work W20.

In this way, the search unit 110 acquires the first distance dv1 from the first position P1 to the first work W10 in the first search, and is located at a predetermined distance dh0 away from the first position P1 in the second search. The second distance dv2 from the second position P2 to the first work W10 is acquired. Then, the inclination calculation unit 120 calculates the inclination α of the first work W10 based on the first distance dv1, the predetermined distance dh0, and the second distance dv2. Further, in the third search, the search unit 110 searches for the second work W20 by moving the contact sensor 22 along the inclination α of the first work W10, and reliably detects the second work W20. There is.

As described above, according to the welding position detection device 100 and the welding position detection method 300 according to the first embodiment of the present invention, the contact type sensor 22 erroneously detects an unintended contact with the first work W10. And it is possible to avoid a missed swing that the second work W20 cannot be detected. That is, even when the first work W10 is tilted, it is possible to reduce erroneous detection of the welding position.

In step S307 described above, the inclination calculation unit 120 calculates the inclination α of the first work W10 based on the first distance dv1, the predetermined distance dh0, and the second distance dv2, but the present invention is limited to this. However, for example, the coordinate values at the contact points between the contact sensor 22 and the first work W10 may be acquired, and the inclination α may be calculated based on the coordinate values.

FIG. 5 is a diagram showing how the inclination calculation unit 120 calculates the inclination of the first work based on the coordinate values in the welding position detecting device 100 according to the first embodiment of the present invention. In FIG. 5, the search unit 110 acquires the first coordinate value at the contact point A between the contact sensor 22 and the first work W10 in step S302, and the contact sensor 22 and the first work W10 in step S306. The second coordinate value at the contact point B of the above is acquired.

Here, it is assumed that the vector X in the search direction has already been taught, but the vector Y can be calculated by the second coordinate value − the first coordinate value. Then, the slope α of the first work W10 can be calculated by α = cos ^-1 ((XY) / (| X || Y |)) using the vector X and the vector Y.

As described above, even if the first distance dv1 and the second distance dv2 are not necessarily acquired, the inclination calculation unit 120 has the first coordinate value at the contact point A and the second coordinate value at the contact point B. The inclination α of the work W10 can be calculated.

In the present embodiment, in step S304, the search unit 110 moves the contact sensor 22 in the horizontal direction, but it does not have to be exactly in the horizontal direction. In step S309, the contact sensor 22 is moved along the inclination α of the first work W10, and in step S310, the contact sensor 22 can be brought into contact with the second work W20 perpendicularly for detection. .. In other words, if the inclination α of the first work W10 can be calculated in order to bring the contact sensor 22 into contact with the second work W20 perpendicularly, the movement of the contact sensor 22 in step S304 is not exactly horizontal. It doesn't matter. For example, it may be substantially horizontal, which is generally horizontal. As a result, the operator does not need to make strict settings for accurately moving the contact sensor 22 in the horizontal direction, the man-hours for teaching are reduced, and as a result, the productivity is improved.

Similarly, the movement of the contact sensor 22 in steps S301 and S305 does not have to be exactly in the vertical direction. However, depending on the degree of inclination of the first work W10, unintended contact may occur or the inclination may not be calculated accurately when the contact type sensor 22 is moved, so that these problems occur. In the case where it is not used and in the range, for example, it may be substantially vertical, which is generally vertical.

Further, in the present embodiment, after the search unit 110 detects the first work W10 in step S302, the contact sensor 22 is once moved to the second position P2 via the first position P1 in steps S303 and S304. Although it is moved, it may be moved directly to the second position P2 without going through the first position P1. In this case, since the contact sensor 22 can move to the second position P2 in the shortest distance after coming into contact with the first work W10, the processing speed can be increased.

Further, in the present embodiment, in step S308, the contact sensor 22 is retracted in the vertical direction with respect to the first work W10, but the present invention is not limited to this, and for example, the search direction is the same as in step S303. You may evacuate in the opposite direction. In this case, high-speed processing can be easily performed without being affected by the calculation result of the inclination α of the first work W10 in step S307.

In this embodiment, the lap joint has been described as an example, but the present invention is not limited to this, and can be applied to other welded joints such as fillet joints and the like.

<Second Embodiment>
In the first embodiment of the present invention, in the first search and the second search, the inclination α of the first work W10 is calculated by searching the work twice in the vertical direction, and the welding position is appropriately detected. In the second embodiment of the present invention, a welding position detection method for calculating the inclination of the work by searching the work twice in the horizontal direction and appropriately detecting the welding position will be described. Since the configuration of the welding position detecting device according to the second embodiment of the present invention is the same as the configuration of the welding position detecting device 100 shown in FIG. 2, detailed description thereof will be omitted.

FIG. 6 is a flowchart showing a welding position detection method 500 executed by the welding position detection device 100 according to the second embodiment of the present invention, and FIG. 7 is a flowchart showing the welding position detection device 100 according to the second embodiment of the present invention. It is a figure which shows the mode that the 1st work and the 2nd work are searched by the contact type sensor. Hereinafter, (1) to (6) shown in the specification correspond to the circled numbers 1 to 6 shown in FIG. 7.

In FIG. 6, the welding position detecting method 500 includes steps S501 to S510, and each step is executed by a processor included in the welding position detecting device 100. Further, here, as shown in FIG. 7, a case where the first work W11 and the second work W21 are arranged and welded so as to be orthogonal to each other is described by taking a so-called fillet joint as an example. do.

In step S501, the search unit 110 moves the contact sensor 22 (welding torch 21) in the horizontal direction from the first position Q1 to search the first work W11 (1).

In step S502, the contact detection unit 111 in the search unit 110 detects the contact between the contact sensor 22 (welding wire protruding from the tip of the welding torch 21) and the first work W11. As a result, the search unit 110 acquires the first distance dh1 from the first position Q1 to the first work W11 based on the moving distance of the contact sensor 22.

Steps S501 and S502 are first searches for searching the first work W11 in the horizontal direction from the first position Q1 and acquiring the first distance dh1.

In step S503, the search unit 110 moves the contact sensor 22 by the first distance dh1 in the direction opposite to the search direction in step S501 (2). More specifically, the search unit 110 moves the contact sensor 22 moved in steps S501 and S502 by the first distance dh1 in the direction opposite to the search direction, and moves the contact sensor 22 to the first position Q1. return. The search direction is a horizontal direction and a direction approaching the first work W11, and a direction opposite to the search direction is a horizontal direction and a direction away from the first work W11.

Here, as a post-processing of the first search, the search unit 110 brings the contact sensor 22 into contact with the first work W11, and then retracts the contact sensor 22 in the direction opposite to the search direction. Actually, it is the welding wire protruding from the tip of the welding torch 21 that comes into contact with the first work W11, and the welding wire may be burdened by the contact. Therefore, after the contact is made, the welding wire or the like is retracted in the direction opposite to the contact search direction to reduce the load on the welding wire or the like due to the contact and prevent the welding wire or the like from bending.

Further, the search unit 110 moves the contact sensor 22 by the first distance dh1 and returns it to the first position Q1. If the first work W11 is tilted to a considerable extent, if the contact sensor 22 is moved in the vertical direction in the next step S504, unintended contact may occur with the first work W11. A sufficient distance is secured for the work W11. The first position Q1 is set as a search start position at a position where a sufficient distance is secured with respect to the first work W11 so that unintended contact with the first work W11 does not occur.

In other words, the search unit 110 does not have to return the contact sensor 22 to the first position Q1 and moves a distance larger than the first distance dh1 to secure a sufficient distance with respect to the first work W11. It doesn't matter. Further, if it is possible to avoid unintended contact with the first work W11 when the contact type sensor 22 is moved in the vertical direction, the contact type sensor 22 may be moved by a distance smaller than the first distance dh1. I do not care.

In step S504, the search unit 110 moves the contact sensor 22 to the second position Q2 separated by a predetermined distance dv0 in the vertical direction (3).

Here, the search unit 110 is supposed to move the contact type sensor 22 in the vertical direction, but this is a direction away from (approaching direction) to the second work W21, and typically, the first work W11. It is a direction away from (a direction toward approaching) the welding line position between the second work W21 and the second work W21. By locating the first position Q1 and the second position Q2 in a direction away from (approaching) the welding line position, it becomes possible to calculate the inclination of the first work W11 with respect to the direction. As a result, the contact type sensor 22 can surely avoid erroneous detection of contact with the first work and missed swing that the second work cannot be detected.

Further, if the search unit 110 moves the contact sensor 22 in a direction approaching the second work W21, an unintended contact may occur with the second work W21. Therefore, the search unit 110 is closer to the second work W21. It is more preferable to move the sensor away from it.

In step S505, the search unit 110 searches the first work W11 by moving the contact sensor 22 in the horizontal direction again from the second position Q2 (4).

In step S506, the contact detection unit 111 in the search unit 110 detects the contact between the contact sensor 22 (welding wire protruding from the tip of the welding torch 21) and the first work W11. As a result, the search unit 110 acquires the second distance dh2 from the second position Q2 to the first work W11 based on the moving distance of the contact sensor 22.

Steps S505 and S506 are second searches for searching the first work W11 in the horizontal direction from the second position Q2 and acquiring the second distance dh2.

In step S507, the inclination calculation unit 120 calculates the inclination β of the first work W11 based on the first distance dh1, the predetermined distance dv0, and the second distance dh2. Here, it can be calculated by the slope β = (first distance dh1-second distance dh2) / predetermined distance dv0.

In step S508, after the contact sensor 22 and the first work W11 are brought into contact with each other, the search unit 110 attaches to the first work W11 based on the inclination β of the first work W11 calculated by the inclination calculation unit 120. On the other hand, the contact sensor 22 is moved in the vertical direction by a distance d2 (5).

Here, as a post-processing of the second search, the search unit 110 brings the contact sensor 22 into contact with the first work W11, and then retracts the contact sensor 22 in the direction perpendicular to the first work W11. ing. Actually, it is the welding wire protruding from the tip of the welding torch 21 that comes into contact with the first work W11, and the welding wire may be burdened by the contact. Therefore, by retracting the work W11 in the vertical direction after the contact, the load on the welding wire or the like due to the contact is reduced, and the welding wire or the like is prevented from bending.

Further, the search unit 110 moves the contact sensor 22 by a distance d2. Here, if the distance d2 is too small, if there is a measurement error, a calculation error, unevenness on the surface of the first work W11, or the like, when the contact sensor 22 moves in step S509 described later, the first work W11 There is a possibility of accidental contact with. On the other hand, if the distance d2 is too large, the contact sensor 22 cannot come into contact with the second work W21 in step S510 described later, and there is a possibility that the contact sensor 22 will miss the second work W21. Therefore, here, the distance d2 is a range that does not protrude from the end of the second work W21, and holds a distance that does not erroneously contact the first work W11 when the contact sensor 22 moves in step S509. It should be set so that it can be done.

In step S509, the search unit 110 searches the second work W21 by moving the contact sensor 22 along the inclination β of the first work W11 calculated by the inclination calculation unit 120 in step S507 (6).

In step S510, the contact detection unit 111 in the search unit 110 detects the contact between the contact type sensor 22 (welding wire protruding from the tip of the welding torch 21) and the second work W21. As a result, the search unit 110 acquires the distance to the second work W21 based on the moving distance of the contact sensor 22. This is a third search for searching the second work W21 along the inclination β of the first work W11 and acquiring the distance to the second work W21.

In this way, the search unit 110 acquires the first distance dh1 from the first position Q1 to the first work W11 in the first search, and is located at a predetermined distance dv0 away from the first position Q1 in the second search. The second distance dh2 from the second position Q2 to the first work W11 is acquired. Then, the inclination calculation unit 120 calculates the inclination β of the first work W11 based on the first distance dh1, the predetermined distance dv0, and the second distance dh2. Further, in the third search, the search unit 110 searches for the second work W21 by moving the contact sensor 22 along the inclination β of the first work W11, and reliably detects the second work W21. There is.

As described above, according to the welding position detection device 100 and the welding position detection method 500 according to the second embodiment of the present invention, the contact type sensor 22 erroneously detects an unintended contact with the first work W11. And it is possible to avoid a missed swing that the second work W21 cannot be detected. That is, even when the first work W11 is tilted, it is possible to reduce erroneous detection of the welding position.

As described with reference to FIG. 5 in the first embodiment, also in the present embodiment, the inclination calculation unit 120 has the coordinates at the contact point between the contact sensor 22 and the first work W11 in steps S502 and S506. You may acquire each value and calculate the slope β based on the coordinate value. As a result, even if the first distance dh1 and the second distance dh2 are not necessarily acquired, the inclination calculation unit 120 can use the first work W11 based on the coordinate values at the contact points between the contact sensor 22 and the first work W11. The slope β of can be calculated.

In the present embodiment, in step S504, the search unit 110 moves the contact sensor 22 in the vertical direction, but it does not have to be exactly in the vertical direction. In step S509, the contact sensor 22 can be moved along the inclination β of the first work W11, and in step S510, the contact sensor 22 can be brought into vertical contact with the second work W21 for detection. .. In other words, if the inclination β of the first work W11 can be calculated in order to bring the contact sensor 22 into contact with the second work W21 perpendicularly, the movement of the contact sensor 22 in step S504 is not exactly in the vertical direction. It doesn't matter. For example, it may be substantially vertical, which is generally vertical. As a result, the operator does not need to make strict settings for accurately moving the contact sensor 22 in the vertical direction, the man-hours for teaching are reduced, and as a result, the productivity is improved.

Similarly, the movement of the contact sensor 22 in steps S501 and S505 does not have to be exactly horizontal. However, depending on the degree of inclination of the first work W11, unintended contact may occur or the inclination may not be calculated accurately when the contact type sensor 22 is moved, so that these problems occur. In the case where it is not used and in the range, for example, it may be substantially horizontal, which is generally horizontal.

Further, in the present embodiment, the search unit 110 detects the first work W11 in step S502, and then in steps S503 and S504, temporarily moves the contact sensor 22 to the second position Q2 via the first position Q1. Although it is moved, it may be moved directly to the second position Q2 without going through the first position Q1. In this case, since the contact sensor 22 can move to the second position Q2 in the shortest distance after coming into contact with the first work W11, the processing speed can be increased.

Further, in the present embodiment, in step S508, the contact sensor 22 is retracted in the vertical direction with respect to the first work W11, but the present invention is not limited to this, and for example, the search direction is the same as in step S503. You may evacuate in the opposite direction. In this case, high-speed processing can be easily performed without being affected by the calculation result of the slope β of the first work W11 in step S507.

In this embodiment, the fillet joint has been described as an example, but the present invention is not limited to this, and can be applied to other welded joints such as lap joints and the like.

<Others>
In the first embodiment of the present invention, the search unit 110 moves the contact sensor 22 in the vertical direction to search the first work W10 twice, and in the second embodiment of the present invention, the search unit 110 makes contact. The first work W11 was searched twice by moving the formula sensor 22 in the horizontal direction. As a result, even if the first work W10 and the first work W11 are tilted with respect to the horizontal plane and the vertical plane, the second work W20 and the second work W21 are properly detected. Here, the search direction is typically a vertical direction and a horizontal direction, but is not limited to these, and for example, an arbitrary direction including a substantially vertical direction and a substantially horizontal direction is set as the search direction. And can also be applied.

Further, conventionally, it has been difficult to apply a welding position detection device that detects a welding position using a contact sensor as a response to the inclination of the work, but according to the present invention, the work is inclined. It can be applied even in some cases, and it can be said that it leads to the expansion of the applicable range.

Each of the embodiments described above is for facilitating the understanding of the present invention, and is not for limiting the interpretation of the present invention. Each element included in each embodiment and its arrangement, material, condition, shape, size and the like are not limited to those exemplified, and may be appropriately changed. Further, it is possible to partially replace or combine the configurations shown in different embodiments.

10 ... Robot system, 20 ... Welding robot, 21 ... Welding torch, 22 ... Contact sensor, 30 ... Teach pendant, 40 ... Robot control device, 50 ... Power supply, 100 ... Welding position detector, 110 ... Search unit, 111 ... Contact detection unit, 112 ... Voltage application command unit, 120 ... Tilt calculation unit, 130 ... Control unit, 300, 500 ... Welding position detection method, S301 to S310 ... Welding position detection method 300 steps, S501 to S510 ... Welding position Each step of the detection method 300, W10, W11 ... 1st work, W20, W21 ... 2nd work, P1, Q1 ... 1st position, P2, Q2 ... 2nd position, dh1, dv1 ... 1st distance, dh2, dv2 ... second distance, dh0, dv0 ... predetermined distance, d1, d2 ... vertical distance, α, β ... tilt, A, B ... contact point, X, Y ... vector

Claims (6)

A welding position detection device that detects the welding position using a contact sensor.
By moving the contact type sensor from the first position to the first direction and bringing the contact type sensor into contact with the first work to be welded, the first distance from the first position to the first work. Or, with the first search unit that acquires the first coordinate value at the contact point,
The contact type sensor is moved from the second position located at a predetermined distance in the second direction perpendicular to the first direction from the first position to the first direction, and the contact type sensor and the first work are moved. The second search unit that acquires the second coordinate value at the second distance from the second position to the first work or the contact point by contacting with the second search unit.
A tilt calculation unit that calculates the tilt of the first work based on the first distance, the predetermined distance, the second distance, or the first coordinate value and the second coordinate value.
A third search unit that moves the contact sensor along the inclination of the first work to acquire the distance to the second work joined to the first work.
A welding position detector. The second direction is a direction away from the second work.
The welding position detecting device according to claim 1. The first direction is a vertical direction or a horizontal direction.
The welding position detecting device according to claim 1 or 2. The first search unit brings the contact sensor into contact with the first work, and then retracts the contact sensor in the direction opposite to the first direction.
The welding position detecting device according to any one of claims 1 to 3. The first search unit retracts at least the first distance.
The welding position detecting device according to claim 4. The second search unit contacts the contact sensor and the first work, and then, based on the inclination of the first work calculated by the inclination calculation unit, the second search unit is in a direction perpendicular to the first work. To retract the contact sensor,
The welding position detecting device according to any one of claims 1 to 5.

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