JP2016055345A - Camera position adjusting device, welding robot system, and camera position adjusting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem in which: a camera position, a diaphragm and exposure time or the like are needed to be readjusted when a single focus camera is reattached when the single focus camera is once removed for maintenance or the like; and the setting are largely deviated according to adjusting persons when manual adjustment is performed.SOLUTION: A camera position adjusting device includes: a determination section; and a signal generation section. The determination section compares a first image accurately focused on a welding region with a plurality of second images which are imaged from the same view point direction as the view point direction of the first image and have mutually different imaging distances so as to determine a focusing camera position accurately focused on the welding region of a single focus camera directed to the welding region. The signal generation section generates a control signal to set the imaging position of the single focus camera to the focusing camera position. Accordingly, when the imaging position of the single focus camera is set, human determination is not needed to be interposed, thereby enabling reduction of setting deviations of the single focus camera.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a camera position adjustment device, a welding robot system, and a camera position adjustment method.

  If the workpiece is distorted during the welding process or the accuracy of the workpiece is not very good, the distance between the welding torch and the groove center may deviate from the initially assumed value. In this case, it is difficult to perform stable welding, which may cause poor welding. As a countermeasure, for example, the welding torch position is corrected by capturing an image of the welding region with a camera and detecting the amount of deviation of the groove position from the image obtained by the imaging (see Patent Document 1).

JP2000-301340

  When incorporating the camera into the welding robot system, it is necessary to set the camera position, aperture, exposure time, and the like. However, since the welding region to be imaged includes a region where arc light is emitted, the contrast may be too large and the camera may be overexposed. Therefore, a filter that attenuates arc light is usually attached to the camera. Since the arc light contains a large amount of visible light, a filter that selectively attenuates visible light is attached to the camera. Setting of a camera to which such a filter is attached is performed as follows, for example.

  First, with the filter removed, the camera position is adjusted so that the weld bead of the workpiece is in focus. Thereafter, a filter is attached, and the aperture and exposure time are adjusted while performing arc welding. This series of operations is repeated several times as necessary.

  The camera may be temporarily removed due to maintenance or the like. In this case, when the camera is reinstalled, the above-described series of operations are performed. However, human judgment is involved in this series of operations. Therefore, the camera settings vary depending on the person who made the adjustment.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a camera position adjusting device, a welding robot system, and a camera position adjusting method capable of reducing variation in setting of cameras.

  The camera position adjustment apparatus of the present invention includes a determination unit and a signal generation unit. The determination unit compares the first image focused on the welding region with a plurality of second images captured from the same viewpoint direction as the first image and having different imaging distances. The position of the in-focus camera focused on the welding area of the single-focus camera directed to is determined. The signal generation unit generates a control signal for setting the imaging position of the single focus camera to the in-focus camera position.

  The welding robot system of the present invention includes a moving unit, a determining unit, a signal generating unit, and an adjusting unit. The moving part has a welding torch including a welding electrode, and arc welding is performed by moving the welding torch. The determination unit compares the first image focused on the welding region including the tip of the welding electrode and a plurality of second images captured from the same viewpoint direction as the viewpoint direction of the first image and having different imaging distances. Thus, the position of the in-focus camera focused on the welding area of the single focus camera directed to the welding area is determined. The signal generation unit generates a control signal for setting the imaging position of the single focus camera to the in-focus camera position. The adjustment unit is configured to set the imaging position of the single focus camera based on a control signal from the signal generation unit.

The camera position adjustment method of the present invention includes the following two steps.
(1) By comparing the first image focused on the welding region with a plurality of second images captured from the same viewpoint direction as the first image and having different imaging distances, the welding region Determination step of determining a focused camera position focused on the welding area of the directed single-focus camera (2) Signal generation step of generating a control signal for setting the imaging position of the single-focus camera to the focused camera position

  In the camera position adjustment device, the welding robot system, and the camera position adjustment method of the present invention, the first image focused on the welding area is compared with a plurality of second images having different imaging distances. Thereby, an image focused on the welding area can be selected from the plurality of second images. By setting the imaging position of the single focus camera to the camera position when the selected second image is captured, the focus of the single focus camera can be adjusted to the welding area. In the present invention, a control signal for generating the imaging position of the single focus camera as the in-focus camera position is generated. Thereby, the setting of the imaging position of the single focus camera can be performed by the adjustment unit that sets the imaging position of the single focus camera based on the control signal.

  According to the camera position adjustment device, the welding robot system, and the camera position adjustment method of the present invention, an image focused on the welding area is selected from the plurality of second images, and the imaging position of the single focus camera is selected. Since the control signal to be set at the camera position when the second image is captured is generated, it is not necessary to involve human judgment when setting the imaging position of the single focus camera. As a result, it is possible to reduce the setting variation of the single focus camera.

It is a figure showing an example of schematic structure of the welding robot system of one embodiment of the present invention. It is a figure showing an example of the section composition of a standard work and an object work. It is a figure for demonstrating the position shift of a target workpiece | work. It is a figure showing an example of a situation of arc welding in perspective. It is a figure showing an example of the image obtained by an imaging device. It is a figure showing an example of schematic structure of the robot control apparatus of FIG. It is a figure showing an example of schematic structure of the teach pendant of FIG. It is a figure showing an example of schematic structure of the image processing apparatus of FIG. It is a figure showing an example of an initial camera position adjustment procedure. It is a figure showing an example of the camera position adjustment procedure again. It is a figure showing the other example of the camera position adjustment procedure again.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

<1. Embodiment>
Initially, the outline | summary of the welding robot system 1 which concerns on one embodiment of this invention is demonstrated. FIG. 1 shows an example of a schematic configuration of a welding robot system 1. The welding robot system 1 performs arc welding on a workpiece W by a program-controlled articulated robot. The welding robot system 1 corresponds to a specific example of the “welding robot system” of the present invention.

  For example, as illustrated in FIG. 2, the workpiece W includes two base materials B1 and B2 arranged in the same plane. The side surface S1 of the base material B1 and the side surface S2 of the base material B2 are arranged close to each other. A V-shaped groove shape is formed by the side surface S1 and the side surface S2. Note that the workpiece W is not limited to one having a V-shaped groove shape.

  The welding robot system 1 employs a so-called teaching & playback system. The teaching and playback method is a method that uses welding torch coordinate information along the welding position (groove position) of the workpiece W, which is set in advance as teaching data by an operator, etc. Refers to the method to be performed. The welding robot system 1 further employs copying control. In the copying control, when the workpiece W is displaced, correction is performed on the preset teaching data according to the displacement of the workpiece W, so that the welding torch can be opened more accurately. This refers to the control along the tip position. The welding robot system 1 obtains correction data used for copying control from image data obtained by an imaging device 20 described later.

(Position shift of work W)
Note that the above-mentioned “positional displacement of the workpiece W” means, for example, as shown in FIG. 3, when a welding torch 13 (described later) is arranged based on the teaching point, the groove position of the workpiece W (welding) The line WL) indicates that the welding electrode 14 (described later) fixed to the welding torch 13 is displaced from the tip position. The “positional displacement of the workpiece W” refers to, for example, the relationship between the welding line WL of the workpiece W and the tip position of the welding electrode 14 in the left-right direction (D1 direction in FIG. 3) and the vertical direction (D2 direction in FIG. 3). It means that it is displaced in at least one direction.

[Constitution]
Next, the configuration of the welding robot system 1 will be described. As shown in FIG. 1, the welding robot system 1 includes a manipulator 10, an imaging device 20, an adjustment device 30, a robot control device 40, a teach pendant 50, a welder 60, and an image processing device 70. I have. The manipulator 10 corresponds to a specific example of the “moving unit” of the present invention. The imaging device 20 corresponds to a specific example of a “single focus camera” of the present invention. The adjusting device 30 corresponds to a specific example of the “adjusting unit” of the present invention. A device including the robot control device 40 and the image processing device 70 corresponds to a specific example of “camera position adjusting device” of the present invention. The robot control device 40 corresponds to a specific example of a “signal generation unit” of the present invention. The image processing apparatus 70 corresponds to a specific example of the “determination unit” of the present invention. The robot control device 40 and the image processing device 70 may be configured separately from each other as illustrated in FIG. 1 or may be configured integrally with each other. Further, the robot control device 40 and the teach pendant 50 may be configured separately from each other as illustrated in FIG. 1 or may be configured integrally with each other.

  The welding robot system 1 includes, for example, cables L1 to L8 that connect various devices to each other. The cable L <b> 1 is a communication cable for communicating between the robot control device 40 and the manipulator 10, and is connected to the robot control device 40 and the manipulator 10. The cable L2 is a communication cable for communicating between the robot control device 40 and the teach pendant 50, and is connected to the robot control device 40 and the teach pendant 50. The cable L3 is a communication cable for communicating between the robot control device 40 and the welding machine 60, and is connected to the robot control device 40 and the welding machine 60. The cable L4 is a communication cable for communicating between the robot control device 40 and the image processing device 70, and is connected to the robot control device 40 and the image processing device 70. The cable L5 is a communication cable for communicating between the robot control device 40 and the adjustment device 30, and is connected to the robot control device 40 and the adjustment device 30. The cables L6 and L7 are power cables for supplying a high welding voltage Vs between a welding electrode 14 (to be described later) and the workpiece W. The cable L6 is connected to the welding machine 60 and a worktable 15 described later, and the cable L7 is connected to the welding machine 60 and a welding torch 13 described later. The cable L8 is a communication cable for communicating between the image processing device 70 and the imaging device 20, and is connected to the image processing device 70 and the imaging device 20.

(Manipulator 10)
The manipulator 10 performs arc welding on the workpiece W by moving the welding torch 13 based on a control signal from the robot control device 40. The manipulator 10 includes a base member 11 fixed to a floor or the like, a multi-joint arm portion 12 provided on the base member 11, a welding torch 13 connected to the tip of the multi-joint arm portion 12, a work table 15, have. The welding torch 13 includes a welding electrode 14. The welding electrode 14 is fixed to the tip portion of the welding torch 13. The welding torch 13 corresponds to a specific example of the “welding torch” of the present invention. The welding electrode 14 corresponds to a specific example of “welding electrode” of the present invention.

  The multi-joint arm unit 12 includes, for example, a plurality of arms 12A and a joint shaft (not shown) that rotatably connects the two arms 12A. The articulated arm unit 12 is further provided, for example, one for each arm 12A, and is connected to a plurality of drive motors (not shown) that drive the corresponding arm 12A and each of the drive motors. And an encoder (not shown) for detecting the current position. Each drive motor is driven by a control signal input from the robot controller 40 via the cable L1. By driving each drive motor in this way, each arm 12A is displaced, and as a result, the welding torch 13 moves up and down, front and rear, and right and left. The encoder outputs the detected current position of each arm 12A (hereinafter referred to as “position information”) to the robot controller 40 via the cable L1.

  One end (tip) of the articulated arm portion 12 is connected to the welding torch 13, and the other end of the articulated arm portion 12 is connected to the base member 11. The welding electrode 14 is a non-melting electrode and is made of, for example, a metal material with high hardness such as tungsten. The welding torch 13 generates an arc between the tip of the welding electrode 14 and the workpiece W, and melts the workpiece W (and a filler rod) with the heat of the arc, thereby arc welding the workpiece W. Is to do. In addition, when a filler rod is used for arc welding, the manipulator 10 may further include a wire feeding device that supplies the filler rod to the welding torch 13. The welding torch 13 has a contact tip (not shown) electrically connected to the cable L6. The contact tip is configured to supply the welding voltage Vs supplied from the cable L6 to the welding electrode 14.

  The work table 15 is fixed to a floor or the like, and is used as a pedestal on which the work W is installed. The work table 15 may be a positioner for optimally maintaining the torch posture with respect to the workpiece W. When the work table 15 is the above-described positioner, the robot controller 40 drives and controls the positioner shaft. The work table 15 is connected to the welding machine 60 via a cable L5, and is configured to electrically connect the workpiece W and the cable L5 installed on the work table 15.

(Imaging device 20)
The imaging device 20 is a camera with a fixed focal position, for example, a single focus camera. The imaging device 20 is fixed at a fixed position in relation to the welding torch 13. The imaging device 20 acquires an image I by performing imaging based on a control signal input from the image processing device 70 via the cable L8. The imaging device 20 has a filter 20 </ b> A that selectively cuts visible light on the light incident surface of the imaging device 20. For example, the filter 20 </ b> A is fixed in a detachable state with respect to the light incident surface of the imaging device 20. The filter 20A is configured to attenuate high-intensity visible light contained in arc light generated during arc welding. The filter 20A is configured to transmit near infrared rays emitted from the tip of the welding electrode 14 during arc welding. Therefore, in the imaging device 20, in the state where the filter 20A is attached, an image in the near infrared region is obtained as the image I. The imaging device 20 is configured to output the image I obtained by imaging to the image processing device 70 via the cable L8.

  The imaging device 20 is fixed to the welding torch 13 via the adjustment device 30, for example. For example, the imaging device 20 is detachably fixed to the adjustment device 30 and can be displaced in the optical axis direction of the imaging device 20 by the adjustment device 30. The viewpoint direction of the imaging device 20 is directed to a welding area WA described later. The imaging device 20 is disposed at a position (focusing camera position Po (not shown)) that is focused on the welding area WA. The welding area WA refers to an area including the tip of the welding electrode 14 and an electrode reflection image IR generated during arc welding. The welding area WA corresponds to a specific example of the “welding area” of the present invention. The in-focus camera position Po corresponds to a specific example of “in-focus camera position” of the present invention.

(Welding area WA, electrode reflection image IR)
The electrode reflection image IR is a reflection image of the tip of the welding electrode 14 reflected on the molten pool WP or the workpiece W. The molten pool WP corresponds to a specific example of the “molten pool” of the present invention. FIG. 4 is a perspective view showing an example of the welding area WA during arc welding. At the time of welding, the near infrared ray radiated from the tip of the welding electrode 14 is reflected by the molten pool WP and the side surfaces S1 and S2 of the workpiece W. As a result, an electrode reflection image IR appears on the molten pool WP and the side surfaces S1, S2 of the workpiece W. The position and size of the electrode reflected image IR change according to the displacement of the workpiece W. For example, when the workpiece W is displaced downward with respect to the welding electrode 14, the electrode reflection image IR reflected on the molten pool WP becomes small, and the electrode reflection image IR reflected on the workpiece W becomes small and moves away from the groove center. Further, for example, when the workpiece W is displaced leftward with respect to the welding electrode 14, the electrode reflection image IR reflected on the molten pool WP is displaced rightward within the molten pool WP, and the electrode reflection image IR reflected on the workpiece W is also converted to the workpiece W. Displaces rightward within W.

(Image I)
FIG. 5 shows an example of the image I. The image I includes, for example, the tip of the welding electrode 14, the molten pool WP, the electrode reflected image IR reflected on the molten pool WP, the electrode reflected image IR reflected on the side surface S1 of the workpiece W, and the electrode reflected on the side surface S2 of the workpiece W. It is an image including the reflected image IR. Note that the image I may be an image including at least one of the tip of the welding electrode 14, the molten pool WP, and the three electrode reflection images IR described above.

(Adjustment device 30)
The adjusting device 30 sets the imaging position of the imaging device 20 based on a control signal from the robot control device 40. The adjusting device 30 is configured to be able to displace the imaging device 20 in the optical axis direction of the imaging device 20. That is, the adjustment device 30 is used for focusing the imaging device 20. For example, the adjusting device 30 is fixed to the welding torch 13.

(Robot control device 40)
FIG. 6 illustrates an example of a schematic configuration of the robot control device 40. The robot control device 40 controls the articulated arm unit 12, the welding machine 60, the image processing device 70, and the adjustment device 30 in accordance with instructions from the teach pendant 50. The robot control device 40 includes a control unit 41, a servo control unit 42, a communication unit 43, and a storage unit 44. Below, it demonstrates in order of the memory | storage part 44, the servo control part 42, the communication part 43, and the control part 41. FIG.

  The storage unit 44 is configured to be able to store various programs and various data files. The storage unit 44 stores control software 44 </ b> A that controls the operation of the articulated arm 12. The control software 44A is stored, for example, in a ROM (read only memory). The storage unit 44 further stores a plurality of work programs 44B in which a procedure for welding work of the manipulator 10 is taught, a copying control program (not shown), and a camera position adjustment program 44C. The copying control program describes a procedure for performing the above-described copying control. The camera position adjustment program 44 </ b> C describes a procedure for performing focusing of the imaging apparatus 20. The camera position adjustment program 44C will be described in detail later.

  The plurality of work programs 44B include, for example, one or more work programs 44B used in the camera adjustment mode and one or more work programs 44B used in the profile welding mode. The plurality of work programs 44B, the copying control program, and the camera position adjustment program 44C are stored in, for example, a hard disk. In the work program 44B, for example, a movement command, a welding command, and the like are described. The movement command may include, for example, a movement start command, a movement stop command, a work path (teaching point), a torch posture, and the like. The welding command may include, for example, an arc welding start command, an arc welding end command, a set value of the welding current Is, a set value of the welding voltage Vs, and the like.

  The storage unit 44 is further configured to be able to store various data generated by executing the camera position adjustment program 44C. An example of a file including such data is a camera position file 44D. The current position data (camera position Pi) of the imaging device 20 can be stored in the camera position file 44D. The camera position Pi is data used for position adjustment of the imaging device 20 in the adjustment device 30 and can be included in a control signal transmitted to the adjustment device 30.

  The servo control unit 42 controls each drive motor of the manipulator 10. In the camera adjustment mode, the servo control unit 42 generates a control signal based on, for example, a movement command described in the work program 44B and position information from the encoder of the manipulator 10. In the copying welding mode, the servo control unit 42 receives, for example, a movement command described in the work program 44B, correction data for the position of the welding torch 13 generated by the execution of the copying control program, and an encoder of the manipulator 10. A control signal is generated based on the position information. The servo control unit 42 controls each drive motor of the manipulator 10 by outputting the generated control signal to the manipulator 10.

  The communication unit 43 communicates with the teach pendant 50 via the cable L2, communicates with the welding machine 60 via the cable L3, communicates with the image processing device 70 via the cable L4, and the cable L5. It communicates with the adjustment apparatus 30 via this. The communication unit 43 receives a work command from the teach pendant 50 and outputs the received work command to the control unit 41. The work command from the teach pendant 50 can include, for example, the number of the work program 44B to be reproduced, the camera adjustment status, and the like. The camera adjustment status may include, for example, initial adjustment or readjustment. In addition, the communication unit 43 transmits a welding command from the control unit 41 to the welding machine 60. The welding command from the control unit 41 may include, for example, an arc welding start command, an arc welding end command, a set value of the welding current Is, or a set value of the welding voltage Vs. In addition, the communication unit 43 transmits an adjustment start command or a copying start command from the control unit 41 to the image processing apparatus 70. The adjustment start command may include a camera adjustment status, for example.

  Based on the work command input from the teach pendant 50, the control unit 41 reads out the work program 44B, the copying control program, and the camera position adjustment program 44C and analyzes the contents. Based on the analysis result of the work program 44B, the control unit 41 generates a command notification in response to an instruction described in the work program 44B. The control unit 41 generates, for example, a movement command, a welding command, an adjustment start command, or a copying start command according to the content of the generated command notification. The control unit 41 outputs a movement command to the servo control unit 42. The control unit 41 outputs a welding command to the welding machine 60 via the communication unit 43. The control unit 41 outputs an adjustment start command or a copying start command to the image processing apparatus 70 via the communication unit 43. The control unit 41 reads the current position data (camera position Pi) of the imaging device 20 from the camera position file 44D in response to the camera position transmission command input from the image processing apparatus 70. The control unit 41 outputs the camera position Pi to the image processing device 70 via the communication unit 43.

(Teach pendant 50)
FIG. 7 illustrates an example of a schematic configuration of the teach pendant 50. The teach pendant 50 is for an operator to teach the operation of the manipulator 10. The teach pendant 50 includes, for example, a control unit 51, a display unit 52, an input unit 53, a communication unit 54, and a storage unit 55.

  The display unit 52 displays a video based on the video signal. The display unit 52 includes a display panel having a display surface for displaying video and a drive unit for driving the display panel based on the video signal. The input unit 53 receives teaching from an operator. The input unit 53 has, for example, a plurality of keys, generates an input signal in response to an operation of each key, and outputs the input signal to the control unit 51. The communication unit 54 communicates with the robot control device 40 via the cable L2. The communication unit 54 is configured to transmit a work command from the control unit 51 to the robot control device 40. The communication unit 54 receives the image I from the robot control device 40 and outputs it to the control unit 51. The storage unit 55 stores teaching software 55A that enables various displays and work instructions in various modes. The teaching software 55A is stored in, for example, a ROM.

  The control unit 51 generates a video signal, outputs it to the display unit 52, generates a work command if necessary, and outputs it to the communication unit 54. The control unit 51 generates a video signal according to the read teaching software 55A, or generates a video signal including the image I received from the robot control device 40. The control unit 51 also generates a work command as necessary. For example, when the input signal input from the input unit 53 is a selection signal for a reproduction mode for performing a machining operation, the control unit 51 performs one or more stored in the storage unit 44 according to the teaching software 55A. A video signal for displaying a list of work programs 44B is generated. Further, for example, when the reproduction mode is selected and one work program 44B to be reproduced is selected, the control unit 51 issues a work command including the number of the work program 44B to be reproduced according to the teaching software 55A. It is designed to generate. Further, for example, when the playback mode is selected, when the monitoring unit 51 acquires the monitoring information from the communication unit 54, the control unit 51 generates a video signal for displaying the acquired monitoring information.

(Welder 60)
The welding machine 60 generates an arc between the tip of the welding electrode 14 and the workpiece W by precisely controlling the welding current Is, the welding voltage Vs, and the like based on a control signal from the robot controller 40. is there.

(Image processing apparatus 70)
FIG. 8 illustrates an example of a schematic configuration of the image processing apparatus 70. The image processing device 70 processes the image I obtained from the imaging device 20. The image processing apparatus 70 includes a control unit 71, a communication unit 72, and a storage unit 73.

  The storage unit 73 is configured to be able to store various software. The storage unit 73 stores image processing software 73A for processing the image I. The image processing software 73A is stored in, for example, a ROM. The image processing software 73A will be described in detail later. Further, the storage unit 73 is configured to be able to store various data generated by executing the image processing software 73A. Examples of the file including such data include an image file 73B and a setting file 73C. In the image file 73B, for example, a plurality of images I captured by the imaging device 20 can be stored. In the setting file 73C, for example, camera setting values (for example, in-focus camera position Po, aperture, exposure time, etc.) can be stored.

  The communication unit 72 communicates with the robot control device 40 via the cable L4 and communicates with the imaging device 20 via the cable L8. The communication unit 72 receives the adjustment start command or the copying start command from the robot control device 40 and outputs the received adjustment start command or the copying start command to the control unit 71. The communication unit 72 is configured to transmit an imaging start command from the control unit 71 to the imaging device 20. The communication unit 72 receives a plurality of images I from the imaging device 20 and outputs the received plurality of images I to the control unit 71. The communication unit 72 outputs the camera setting values derived from the control unit 71 (for example, the focused camera position Po, the aperture, the exposure time, and the like) to the imaging device 20.

  The control unit 71 reads the image processing software 73A based on the adjustment start command or the copying start command input from the robot control device 40, and analyzes the contents thereof. Based on the analysis result, the control unit 71 generates a command notification or executes predetermined arithmetic processing in accordance with an instruction described in the image processing software 73A.

  The control unit 71 is configured to output the generated command notification to the imaging device 20. For example, when the control unit 71 receives an adjustment start command including initial adjustment as the camera adjustment status (in the initial camera adjustment mode), the control unit 71 issues a command notification for capturing one or a plurality of images I at a predetermined timing. , And output to the imaging device 20. This command notification is output when arc welding is performed in the initial camera adjustment. Hereinafter, the image I at this time is referred to as an image Ir.

  In the initial camera adjustment mode, the controller 71 further executes, for example, the following arithmetic processing. For example, when a plurality of images Ir are obtained from the imaging device 20 and there is variation between the images Ir, the control unit 71 may perform a moving average process on the plurality of images Ir. Good. The control unit 71 finally selects one image Ir, and sets the selected image Ir as an image If focused on the welding area WA. The image If corresponds to a specific example of the “first image” of the present invention. The image If is an image focused on the welding area WA. The image If is, for example, an electrode reflection image IR reflected on the tip of the welding electrode 14, the molten pool WP or the workpiece W, or an image focused on the molten pool WP.

  For example, when the control unit 71 receives an adjustment start command including readjustment as the camera adjustment status (in the camera adjustment mode again), the control unit 71 issues a command notification for imaging the image I at every predetermined timing. 20 is output. Hereinafter, the image I obtained in the camera adjustment mode again is referred to as an image Is. The image Is corresponds to a specific example of the “second image” of the present invention. While the control unit 71 outputs a command notification for imaging the image I at every predetermined timing to the imaging device 20, the robot control device 1 is performing arc welding. Therefore, the plurality of images Is obtained by the imaging device 20 are a plurality of images captured from the same viewpoint direction as the viewpoint direction of the image If and having different imaging distances.

  In the camera adjustment mode again, the control unit 71 further performs, for example, the following arithmetic processing. For example, the control unit 71 compares the image If with a plurality of images Is having different imaging distances so as to determine the in-focus camera position Po focused on the welding area WA of the imaging device 20. It has become. For example, the control unit 71 selects an image Is having a predetermined correlation with the image If from the plurality of images Is, and sets the camera position Pi when the selected image Is is captured as the in-focus camera position Po. It comes to judge. For example, the control unit 71 performs pattern matching between the subject included in the image If and the subject included in each image Is, and the camera position Pi when the selected image Is is captured is determined as the in-focus camera position Po. It comes to judge.

  Here, the image Ir and each image Is include at least one of the tip of the welding electrode 14, the electrode reflection image IR reflected on the molten pool WP or the workpiece W, and the molten pool WP as a subject. For example, the control unit 71 obtains the degree of difference between the image If and each image Is and the feature point (that is, the subject) between the image If and each image Is, and the degree of difference is minimized among the plurality of images Is. Pattern matching is performed by selecting the image Is.

  For example, when receiving a scanning start command (in the scanning welding mode), the control unit 71 outputs a command notification for capturing an image I at every predetermined timing to the imaging device 20. The control unit 71 further derives correction data of the position of the welding torch 13 based on, for example, a plurality of acquired images I in the copying welding mode.

[Operation]
Next, the operation procedure of the welding robot system 1 in the camera adjustment mode will be described.

(Initial camera adjustment mode)
FIG. 9 illustrates an example of operation procedures of the robot control device 40, the image processing device 70, and the imaging device 20 in the initial camera adjustment mode.

  First, an operator installs a work W on which a weld bead is formed at a groove position (that is, a welded workpiece) on the work table 15. Next, the operator removes the filter 20 </ b> A from the imaging device 20, illuminates the imaging location, and focuses the imaging device 20 while confirming the image I captured by the imaging device 20 in that state. At this time, for example, the operator focuses on the weld bead. Next, instead of the welded workpiece W, the worker installs the workpiece W on which the weld bead is not formed at the groove position (that is, unwelded) on the work table 15. Next, the operator attaches the filter 20A to the imaging device 20, and instructs the teach pendant 50 to start the initial camera adjustment. Then, the teach pendant 50 generates a work command including initial adjustment as a camera adjustment status in accordance with an instruction to start initial camera adjustment input from the operator, and transmits the generated work command to the robot control device 40. .

  The robot control device 40 receives a work command including initial adjustment as a camera adjustment status from the teach pendant 50 (step S101). Then, the robot control device 40 reads the work program 44B having the corresponding number, and generates a command notification in accordance with the instruction described in the work program 44B. The robot control device 40 transmits a movement command to the manipulator 10 and transmits a welding command to the welding machine 60. The manipulator 10 controls the welding torch 13 according to a control signal from the robot control device 30. When receiving the welding command from the robot controller 30, the welding machine 50 controls, for example, the welding current Is and the welding voltage Vs in accordance with the contents. As a result, arc welding is started. The robot control device 40 further transmits an adjustment start command including initial adjustment as a camera adjustment status to the image processing device 70 (step S102).

  When the image processing apparatus 70 receives such an adjustment start command from the robot control apparatus 40 (step S103), for example, the internal state is initialized. Thereafter, the image processing device 70 transmits an imaging start command to the imaging device 20 (step S104). When the imaging device 20 receives an imaging start command from the image processing device 70 (step S105), the imaging device 20 performs imaging at a predetermined timing and acquires one image Ir (step S106). That is, the imaging device 20 acquires one image Ir during a period in which arc welding is performed in the initial camera adjustment. At this time, the imaging device 20 is fixed at a predetermined position. Thereafter, the imaging device 20 transmits the acquired image Ir to the image processing device 70 (step S107). The image processing device 70 receives the image Ir from the imaging device 20 (step S108).

  When receiving the image Ir from the imaging device 20, the image processing device 70 requests the robot control device 40 for the camera position Pi when the received image Ir is captured (step S109). When receiving the request for the camera position Pi (step S110), the robot control device 40 reads the camera position Pi from the camera position file 44D and transmits the read camera position Pi to the image processing device 70 (step S111). When the image processing device 70 receives the camera position Pi from the robot control device 40 (step S112), the image processing device 70 stores the camera position Pi in association with the image Ir in the storage unit 73.

  At this time, if the brightness of the image Ir is within a desired range, the operator ends the initial camera adjustment. Specifically, the operator instructs the teach pendant 50 to end the initial camera adjustment. Then, the teach pendant 50 generates an adjustment end work command in accordance with an initial camera adjustment end instruction input by the operator, and transmits the generated work instruction to the robot control device 40. The robot control device 40 receives an adjustment completion work command from the teach pendant 50 (step S113). Then, the robot control device 40 generates an adjustment end command and transmits the generated adjustment end command to the image processing device 70 (step S114).

  When receiving the adjustment end command from the robot control device 40 (step S115), the image processing device 70 determines that the image Ir is an image Ir ′ in focus on the welding area WA, and the camera position associated with the image Ir ′. Let Pi be the in-focus camera position Po. The image processing apparatus 70 determines a region for extracting a focused subject from the image Ir ′, and extracts an image of the determined region from the image Ir ′ as an image If. The image processing apparatus 70 stores the extracted image If in the image file 73B (step S116). The image If is an image focused on the welding area WA, and corresponds to a specific example of the “first image” of the present invention. The image processing device 70 further transmits the in-focus camera position Po to the robot control device 40 (step S117). When receiving the in-focus camera position Po from the image processing apparatus 70, the robot controller 40 stores the in-focus camera position Po in the camera position file 44D (step S118). In this way, by executing the initial camera adjustment mode, the image If and the focused camera position Po are obtained.

(Camera adjustment mode again)
FIG. 10 illustrates an example of operation procedures of the robot control device 40, the image processing device 70, and the imaging device 20 in the camera adjustment mode again.

  It is assumed that the operator temporarily removes the imaging device 20 by, for example, maintenance, and then reinstalls the imaging device 20. Next, the worker installs the unwelded workpiece W on the work table 15. Next, the operator instructs the teach pendant 50 to start the camera adjustment again with the filter 20 </ b> A attached to the imaging device 20. Then, the teach pendant 50 generates a work command including readjustment as a camera adjustment status in accordance with an instruction for starting camera adjustment again input from the operator, and transmits the generated work command to the robot controller 40. .

  The robot controller 40 receives a work command including readjustment as a camera adjustment status from the teach pendant 50 (step S201). Then, the robot control device 40 reads the work program 44B having the corresponding number, and generates a command notification in accordance with the instruction described in the work program 44B. The robot control device 40 transmits a movement command to the manipulator 10 and transmits a welding command to the welding machine 60. The manipulator 10 controls the welding torch 13 according to a control signal from the robot control device 30. When receiving the welding command from the robot controller 30, the welding machine 50 controls, for example, the welding current Is and the welding voltage Vs in accordance with the contents. As a result, arc welding is started. The robot control device 40 further transmits an adjustment start command including readjustment as a camera adjustment status to the image processing device 70 (step S202). At this time, the robot control device 40 generates a control signal Sa for setting the imaging device 20 at a predetermined position, and transmits the generated control signal Sa to the adjustment device 30. The adjustment device 30 sets the position of the imaging device 20 according to the control signal received from the robot control device 40.

  When the image processing apparatus 70 receives such an adjustment start command from the robot control apparatus 40 (step S203), for example, the internal state is initialized. Thereafter, the image processing device 70 transmits an imaging start command to the imaging device 20 (step S204). When the imaging device 20 receives an imaging start command from the image processing device 70 (step S205), the imaging device 20 performs imaging at a predetermined timing and acquires one image Is (step S206). That is, the imaging device 20 acquires one image Is during a period in which arc welding is performed in another camera adjustment. At this time, the imaging device 20 is fixed at a predetermined position. Thereafter, the imaging device 20 transmits the acquired image Is to the image processing device 70 (step S207). The image processing device 70 receives the image Is from the imaging device 20 (step S208).

  When receiving the image Is from the imaging device 20, the image processing device 70 requests the robot control device 40 for the camera position Pi when the received image Is is captured (step S209). When receiving the request for the camera position Pi (step S210), the robot control device 40 reads the camera position Pi from the camera position file 44D, and transmits the read camera position Pi to the image processing device 70 (step S211). When the image processing device 70 receives the camera position Pi from the robot control device 40 (step S212), the image processing device 70 stores the camera position Pi in association with the image Is in the storage unit 73.

  Subsequently, the image processing apparatus 70 compares the image If with the image Is to determine whether the image Is is an image in focus on the welding area WA (step S213). Specifically, the image processing device 70 determines whether or not the image If and the image Is have a predetermined correlation. More specifically, the image processing device 70 performs pattern matching between the subject included in the image If and the subject included in the image Is. As a result, when the pattern matching rate between the image If and the image Is is equal to or lower than a predetermined threshold, the image processing device 70 determines that the image Is is not an image in focus on the welding area WA. At this time, the image processing device 70 transmits a command for displacing the camera position Pi by a predetermined amount to the robot control device 40. When receiving such a command from the image processing device 70, the robot control device 40 generates a control signal Sa for displacing the camera position Pi by a predetermined amount (step S214), and adjusts the generated control signal Sa to the adjustment device 30. Send to. The control signal Sa at this time corresponds to a specific example of “a second control signal for shifting the imaging position of the single focus camera” of the present invention. The adjustment device 30 adjusts the current position of the imaging device 20 according to the control signal received from the robot control device 40. After the current position of the imaging device 20 is displaced, the image processing device 70 executes the above step S204 and executes the above step S213 again. That is, in step S206, the imaging device 20 acquires the image I at a position (camera position Pi) different from the previous time. The image processing apparatus 70 repeatedly executes steps S204, S208, S209, S212, and S213 unless the pattern matching rate between the image If and the image Is exceeds a predetermined threshold. At this time, the robot control device 40 generates the control signal Sa so that the imaging position of the imaging device 20 is displaced within a predetermined range including the imaging position of the imaging device 20 when the image If is captured.

  When the pattern matching rate between the image If and the image Is exceeds a predetermined threshold, the image processing apparatus 70 determines that the image Is is an image in focus on the welding area WA, and is selected by the determination. The camera position Pi when the image Is is captured is determined as the in-focus camera position Po. In other words, the control signal Sa transmitted to the adjusting device 30 to set the position of the imaging device 20 at this time is the “first control signal for setting the imaging position of the single focus camera to the in-focus camera position” of the present invention. It corresponds to one specific example. At this time, the image processing device 70 transmits the in-focus camera position Po to the robot control device 40 (step S215). When the robot controller 40 receives the in-focus camera position Po from the image processing apparatus 70, the robot controller 40 stores the in-focus camera position Po in the camera position file 44D (step S216). In this way, when the camera adjustment mode is executed again, the imaging device 20 is automatically set to a position in focus on the welding area WA.

  As shown in FIG. 11, the image processing apparatus 70 performs the camera position until the number of images Is captured by the imaging apparatus 20 reaches a predetermined number (N) after executing Step S212 (Step S217). A command for displacing Pi by a predetermined amount may be transmitted to the robot controller 40. When receiving such a command, the robot control device 40 generates a control signal Sa for displacing the camera position Pi by a predetermined amount until the number of captured images Is reaches a predetermined number (N) (step S214). ). At this time, the image processing apparatus 70 repeatedly executes steps S204, S208, S209, S212, and S217 until the number of images Is captured by the imaging apparatus 20 reaches a predetermined number (N). The robot control device 40 generates the control signal Sa so that the imaging position of the imaging device 20 is displaced within a predetermined range including the imaging position of the imaging device 20 when the image If is captured. The robot control device 40 transmits the generated control signal Sa to the adjustment device 30. The control signal Sa at this time corresponds to a specific example of “a second control signal for shifting the imaging position of the single focus camera” of the present invention. The adjustment device 30 adjusts the current position of the imaging device 20 according to the control signal received from the robot control device 40. The image processing device 70 executes step S204 every time the current position of the imaging device 20 is displaced. That is, in step S206, the imaging device 20 acquires the image I at a position (camera position Pi) different from the previous time. In this way, after acquiring a plurality (N) of images Is having different imaging distances, the image processing apparatus 70 selects an image Is in focus on the welding area WA from the plurality of images Is. (Step S218).

  Specifically, the image processing device 70 performs pattern matching between the subject included in the image If and the subject included in each image Is. The image processing device 70 determines that the image Is whose pattern match rate between the image If and the image Is exceeds a predetermined threshold is an image in focus on the welding area WA, and the image Is selected by the determination is captured. The camera position Pi at this time is determined as the in-focus camera position Po.

  When the pattern match rate of the plurality of images Is exceeds a predetermined threshold, the image processing apparatus 70, for example, among the plurality of images Is whose pattern match rate exceeds the predetermined threshold, the pattern match rate is the maximum. The camera position Pi when the image Is is captured may be determined as the in-focus camera position Po. Further, when the pattern match rate of the plurality of images Is exceeds a predetermined threshold in a certain imaging period, the image processing device 70 is, for example, when the image Is corresponding to the middle of the imaging period is captured. The camera position Pi may be determined as the in-focus camera position Po.

  Further, when the pattern match rate of the plurality of images Is exceeds a predetermined threshold in a plurality of different imaging periods, the image processing device 70, for example, has a pattern match rate of a predetermined value in those imaging periods. The imaging period in which the number of images Is exceeding the threshold is selected is selected, and the camera position Pi when the image Is corresponding to the middle of the selected imaging period is captured is determined as the in-focus camera position Po. It may be. Further, when the pattern match rate of the plurality of images Is exceeds a predetermined threshold in a plurality of different imaging periods, the image processing device 70, for example, has a pattern match rate of a predetermined value in those imaging periods. The imaging period in which the number of images Is exceeding the threshold is maximized, the pattern matching rate of each image Is included in the selected imaging period is approximated by a quadratic curve, and the maximum value of the quadratic curve obtained thereby The camera position Pi corresponding to may be determined as the in-focus camera position Po.

  Thereafter, the image processing device 70 transmits the in-focus camera position Po to the robot control device 40 (step S215). When the robot controller 40 receives the in-focus camera position Po from the image processing apparatus 70, the robot controller 40 stores the in-focus camera position Po in the camera position file 44D (step S216) and adjusts the control signal including the in-focus camera position Po. To device 30. The adjustment device 30 sets the position of the imaging device 20 according to the control signal received from the image processing device 70. In this way, when the camera adjustment mode is executed again, the imaging device 20 is automatically set to a position in focus on the welding area WA.

(Copy welding mode)
It is assumed that the robot control device 40 receives a work command including the number of the work program 44B for the copy welding mode from the teach pendant 50. Then, the robot control device 40 reads the work program 44B having the corresponding number, and generates a command notification in accordance with the instruction described in the work program 44B. For example, the robot control device 40 transmits a predetermined control signal to the manipulator 10 and outputs a welding command to the welding machine 60. The robot control device 40 further transmits a copying start command to the image processing device 70. The manipulator 10 operates the welding torch 13 in response to a control signal from the robot control device 40. When receiving the welding command from the robot controller 40, the welding machine 60 controls, for example, the welding current Is and the welding voltage Vs in accordance with the content of the welding command. As a result, arc welding is started.

  When the image processing apparatus 70 receives a scanning start command from the robot control apparatus 40, the image processing apparatus 70 transmits an imaging start command to the imaging apparatus 20. When the imaging device 20 receives an imaging start command from the image processing device 70, the imaging device 20 captures images at predetermined timings and acquires a plurality of images It. By the way, initially, correction data for the position of the welding torch 13 has not yet been derived. For this reason, the welding torch 13 initially operates along the coordinates of the teaching line.

  The imaging device 20 transmits a plurality of images It captured at predetermined timings to the image processing device 70. The image processing device 70 receives a plurality of images It from the imaging device 20. Thereafter, the image processing device 70 derives correction data of the position of the welding torch 13 based on the acquired one or more images It. The image processing device 70 transmits the derived correction data to the robot control device 40. The robot control device 40 receives the correction data from the image processing device 70. The robot control device 40 corrects the position coordinates of the welding torch 13 based on the correction data, and generates a control signal based on the coordinates considered in the correction data. The robot control device 40 outputs the generated control signal to the manipulator 10. The manipulator 10 operates the welding torch 13 according to the control signal in which the correction data is considered. Therefore, thereafter, the welding torch 13 operates in accordance with the coordinates considered in the correction data. In this way, the robot control device 40 performs copying control of the welding torch 13.

[effect]
Next, the effect of the welding robot system 1 will be described.

  When the imaging device 20 is incorporated in the welding robot system 1, the camera may be temporarily removed due to maintenance or the like. In this case, when reattaching the imaging device 20, for example, with the filter 20A removed, the camera position is adjusted so that the weld bead of the workpiece W is in focus, and then the filter 20A is attached and arc welding is performed. While adjusting, adjust the aperture and exposure time. However, human judgment is involved in this series of operations. Therefore, the camera settings vary depending on the person who made the adjustment.

  On the other hand, in the present embodiment, the image If focused on the welding area WA is compared with a plurality of images Is having different imaging distances. Thereby, the image Is focused on the welding area WA can be selected from the plurality of images Is. By setting the imaging position of the imaging device 20 to the camera position Pi (focused camera position Po) when the selected image Is is captured, the imaging device 20 can be focused on the welding area WA. In the present embodiment, the control signal Sa for generating the imaging position of the imaging device 20 at the in-focus camera position Po is generated. Thereby, the setting of the imaging position of the imaging device 20 can be performed by the adjustment mechanism 30 that sets the imaging position of the imaging device 20 based on the control signal Sa. As a result, since there is no human judgment when setting the imaging position of the imaging device 20, the setting variation of the imaging device 20 can be reduced.

  Further, in the present embodiment, when the image If and each image Is are compared, pattern matching between the subject included in the image If and the subject included in each image Is is performed. As a result, an image Is having a minimum difference between the image If and each image Is is selected from the plurality of images Is, and the camera position Pi of the imaging device 20 when the selected image Is is captured is selected. The imaging device 20 is set. Accordingly, since there is no human judgment, the setting variation of the imaging device 20 can be reduced.

<2. Modification>
In the above embodiment, the welding electrode 14 may be a molten electrode. In the above embodiment, the imaging device 20 may not be a single focus camera as long as the camera has a fixed focal position. Moreover, in the said embodiment, although the imaging device 20 was supposed to be used for copy welding, it may be used for other uses.

  DESCRIPTION OF SYMBOLS 1 ... Welding robot system, 10 ... Manipulator, 11 ... Base member, 12 ... Articulated arm part, 12A ... Arm, 13 ... Welding torch, 14 ... Welding electrode, 15 ... Work table, 20 ... Imaging device, 20A ... Filter, DESCRIPTION OF SYMBOLS 30 ... Adjustment apparatus, 40 ... Robot control apparatus, 41 ... Control part, 42 ... Servo control part, 43 ... Communication part, 44 ... Memory | storage part, 44A ... Control software, 44B ... Work program, 44C ... Camera position adjustment program, 44D ... Camera position file 50 ... Teach pendant 51 ... Control part 52 ... Display part 53 ... Input part 54 ... Communication part 55 ... Storage part 55A ... Teaching software 60 ... Welding machine 70 ... Image processing device , 71 ... Control unit, 72 ... Communication unit, 73 ... Storage unit, 73A ... Image processing software, 73B ... Image file, 73C ... Setting file , D1, D2 ... direction, I, Ir, Ir ', Is, It ... image, IR ... electrode reflection image, L1-L8 ... cable, S1, S2 ... side, W ... work, WB ... weld bead, WL ... Welding wire, W ... work, WP ... molten pool.

Claims (8)

By comparing the first image focused on the welding area with a plurality of second images taken from the same viewpoint direction as the viewpoint direction of the first image and having different imaging distances, the welding image is directed toward the welding area. A determination unit for determining a focused camera position in focus on the welding area of the single focus camera,
A camera position adjustment device comprising: a signal generation unit that generates a first control signal for setting an imaging position of the single focus camera to the focus camera position. The determination unit acquires, as the first image, an image captured by the single focus camera when the single focus camera is fixed at a predetermined position.
The determination unit acquires a plurality of images captured by the single focus camera as a plurality of second images when an imaging position of the single focus camera is displaced within a predetermined range including the predetermined position. The camera position adjusting device according to claim 1. The camera position adjustment device according to claim 2, wherein the signal generation unit generates a second control signal for displacing the imaging position of the single focus camera when the determination unit acquires a plurality of the second images. The determination unit selects an image having a predetermined correlation with the first image from the plurality of second images, and determines the camera position when the selected image is captured as the in-focus camera position. The camera position adjusting device according to any one of claims 1 to 3. The first image and the plurality of second images include, as a subject, a reflected image of the tip reflected on the tip of the welding electrode, a molten pool or a base material, or a molten pool,
The determination unit performs pattern matching between the subject included in the first image and the subject included in each of the second images, and determines a camera position when the selected second image is captured. The camera position adjustment device according to claim 4, wherein the camera position is determined as the in-focus camera position. The first image and the plurality of second images are obtained by imaging the welding region with the single focus camera in a state where a filter that selectively cuts visible light is attached to a light incident surface of the single focus camera. The camera position adjusting device according to any one of claims 1 to 5, wherein the camera position adjusting device is an image obtained by the following. A moving torch that includes a welding electrode, and that performs arc welding by moving the welding torch;
Comparing a first image focused on a welding area including a tip of the welding electrode and a plurality of second images taken from the same viewpoint direction as the viewpoint direction of the first image and having different imaging distances. A determination unit for determining a focus camera position focused on the welding region of the single focus camera directed to the welding region;
A signal generator for generating a control signal for setting the imaging position of the single focus camera to the in-focus camera position;
A welding robot system comprising: an adjustment unit that sets an imaging position of the single focus camera based on a control signal from the signal generation unit. By comparing the first image focused on the welding area with a plurality of second images taken from the same viewpoint direction as the viewpoint direction of the first image and having different imaging distances, the welding image is directed toward the welding area. A determination step of determining a focused camera position focused on the welding area of the single focus camera,
A signal generation step of generating a control signal for setting an imaging position of the single focus camera to the in-focus camera position.

Images