JP5176331B2 - Imaging apparatus and spot welding robot system - Google Patents

Description

  The present invention relates to an imaging device and a spot welding robot system.

In a process in which many spot welding robots are used, such as assembling an automobile, a technique for creating a robot work program in advance is often employed for the purpose of reducing work man-hours when starting up equipment.
As a method of creating a spot welding robot work program in advance, information on the mechanism and shape of the robot and spot welding gun, the shape of the workpiece (workpiece to be welded), the positional relationship between the robot and the workpiece, necessary operating conditions, etc. In addition, an offline teaching system for simulating a robot operation on a computer and creating a work program is used.
However, when using a program created by the offline teaching system with an actual robot, due to factors such as robot and jig installation errors, robot body differences, workpiece dimensional errors, and robot arm deflection due to gravity, The welding position may deviate from previously recorded welding points.

For this reason, before performing automatic operation for all or part of the welding point position, the operator manually operates the robot to check the welding point position, and if there is a deviation, correct the position recorded in the work program. It is necessary to do work to do.
Further, not only when the equipment is started up, but also when the equipment is transferred, the welding point position of the work program used before the equipment transfer may be shifted due to the same factors as described above. In this case as well, it is necessary for the operator to check the position of the welding point by manual operation and to correct the recording position if necessary.
As a method of correcting the work program of the spot welding robot, a method of correcting by measuring a welding point using a visual sensor has been proposed. In order to measure the welding point of the workpiece, it is necessary to measure the welding point with a camera. For example, the camera is attached by replacing one of the two electrodes provided on the spot welding gun (Patent Document 1). ).
Japanese Patent Laid-Open No. 7-325611

By the way, as shown in FIG. 5, the shank 102 which becomes the attachment part of the electrode 101 in a spot welding gun is a taper shape, and it attaches to a spot welding gun by pressing the electrode 101 strongly. When the electrode 101 is attached, for example, the electrode 101 is hit with a tool such as a hammer or two electrodes are brought into contact with each other and pressed. For this reason, when the camera is attached to the spot welding gun instead of the electrode 101, there is a problem that the camera is damaged if the same method as the attachment of the electrode 101 is used.
In addition, as shown in FIG. 5, the shank 102 of the spot welding gun has a structure including a cooling hose 103 that can circulate cooling water to cool the electrodes. There was also a risk of camera failure due to a short circuit.

  Therefore, the present invention has been made to solve the above-described problems, and prevents the camera from being damaged when the camera is attached to the spot welding gun and prevents the camera from being broken due to the application of cooling water. It is an object of the present invention to provide an imaging apparatus and a spot welding robot system that can perform the above-mentioned.

The invention according to claim 1 is provided at the tip of a robot having a plurality of joints, and is provided so as to be exchangeable with one electrode of a spot welding gun having two electrodes opposed to each other, and an optical axis is the electrode. In an imaging apparatus that is provided so as to be coaxial with an axis of the workpiece and that forms an image by imaging a welding point of the workpiece by the electrode, a camera that images an image of the welding point of the workpiece, and the camera as the spot welding gun A mounting portion provided so as to be interposed between the two at the time of mounting; and a protection portion that is connected to the mounting portion and covers the camera head of the camera having an imaging element and a lens that form an image of a welding point of the workpiece. The protective portion is provided with a passage hole through which light passes, or the entire protective portion is formed of a light-transmitting material .
Here, the axis of the electrode refers to an axis that passes through the welding point of the workpiece during spot welding (where the workpiece and the electrode are in contact) and is parallel to the moving direction of the electrode.

According to a second aspect of the present invention, in the imaging apparatus according to the first aspect of the present invention, the imaging device includes a light source that is covered by the protection unit and that irradiates light to the surroundings, and the passage hole of the protection unit is irradiated from the light source. It is characterized in that light directed to a workpiece provided between the other electrode and the camera is passed.

According to a third aspect of the present invention, in the imaging apparatus according to the first or second aspect, the camera includes the camera head and a processing unit that processes an image formed by the camera head, and the camera Only the head is provided so as to be covered with the protective portion.

  According to a fourth aspect of the present invention, in the imaging apparatus according to any one of the first to third aspects, a tool is attached to the surface of the attachment portion when the attachment portion is attached to or detached from the spot welding gun. A fitting portion to be fitted is formed.

The invention according to claim 5 is provided so as to be interchangeable with a robot having a plurality of joints, a spot welding gun having two electrodes disposed opposite to each other at the tip of the robot, An optical device is provided so that the optical axis is coaxial with the axis of the electrode, and an image pickup device for picking up an image of a welding point of a workpiece by the electrode to form an image, and teaching the robot and the spot welding gun to perform a welding operation. A spot welding robot system comprising: storage means for storing a work program stored therein; and control means for controlling operation of the robot and the spot welding gun in accordance with the work program stored in the storage means. A camera that captures an image of the welding point of the workpiece, and an intervening device between the camera and the spot welding gun. A mounting portion provided so as to, be connected to the attachment portion, and a protective portion covering the camera head of the camera having an image sensor and a lens for forming an image of the welding point of the workpiece, the protective portion Further, the present invention is characterized in that a passage hole for allowing light to pass through is provided or the entire protective part is formed of a light-transmitting material .

According to the first aspect of the present invention, since the camera head of the camera is covered with the protection part, when the camera is attached to the spot welding gun, the camera is damaged by hitting the protection part even when tapping with a hammer. The camera can be attached to the spot welding gun together with the protective part without any trouble.
Further, since the attachment portion is provided so as to be interposed between the two when the camera is attached to the spot welding gun, the camera is indirectly attached to the spot welding gun. Accordingly, even if the cooling water is circulated, the water is applied to the mounting portion, so that the cooling water is not applied to the camera, and a failure due to a short circuit of the electric circuit of the camera can be prevented.

According to the second aspect of the present invention, the light emitted from the light source diffuses to the surroundings. However, since the through hole is formed in the protective portion, the light is emitted from the light source and the other electrode is connected to the camera. The light directed to the workpiece provided therebetween passes through the passage hole and jumps out of the protective portion to irradiate the workpiece.
This makes it possible to accurately capture the workpiece even when imaging a portion where a large amount of light is required, such as the inside of the workpiece.

  According to the third aspect of the present invention, since only the camera head of the camera is provided so as to be covered with the protection part, the protection part is more than the case where both the camera head and the processing part are covered with the protection part. Since the size can be reduced, the size of the portion of the camera provided on the spot welding gun can be brought close to the size of the electrode, and the effect of preventing interference between the camera and the workpiece can be enhanced.

  According to the fourth aspect of the present invention, since the fitting portion is formed on the surface of the attachment portion, the tool can be easily fitted when the imaging device is attached to or detached from the spot welding gun. It can be attached to and detached from the spot welding gun while holding the apparatus in a stable state.

According to the invention described in claim 5, since at least a part of the camera is covered with the protective part, when attaching the camera to the spot welding gun, the camera is damaged by hitting the protective part even when tapping with a hammer. Without making it possible, the camera can be attached to the spot welding gun together with the protective part.
Further, since the attachment portion is provided so as to be interposed between the two when the camera is attached to the spot welding gun, the camera is indirectly attached to the spot welding gun. Accordingly, even if the cooling water is circulated, the water is applied to the mounting portion, so that the cooling water is not applied to the camera, and a failure due to a short circuit of the electric circuit of the camera can be prevented.

  Hereinafter, the best embodiment of an imaging device and a spot welding robot system will be described in detail with reference to the drawings.

<Configuration of spot welding robot system>
As shown in FIG. 1, a spot welding robot system 1 includes a multi-axis robot 2 having a plurality of joints 22 and arms 23, a spot welding gun 3 provided at the tip of the robot 2, and a spot welding gun 3. An image pickup device 4 that picks up an image of a welding point of a workpiece to be spot-welded and forms an image, and a control device 5 that controls operations of the robot 2, the spot welding gun 3, the image pickup device 4, and the like are provided.

(robot)
As shown in FIG. 1, the robot 2 is used in a spot welding line such as a body frame of an automobile, for example. The robot 2 includes a base 21 serving as a base, a plurality of arms 23 connected by joints 22, and a servo motor (not shown) that drives the robot 2. And the spot welding gun 3 is provided in the front-end | tip part of the arm 23 located in the most front end among each connected arm 23. FIG.
Each joint 22 is one of a swing joint that pivots one end of the arm 23 and pivotally supports the other end thereof, and a rotary joint that pivotally supports the arm 23 so that the arm 23 itself can rotate around its longitudinal direction. Composed. That is, the robot 2 corresponds to a so-called articulated robot.

(Spot welding gun)
As shown in FIGS. 1 and 2, the spot welding gun 3 includes two electrodes 31 and 32. One electrode 31 is fixed to the arm 33 via a shank 36. The other electrode 32 is provided on a pressure shaft 35 driven by a servo motor, and the electrode 32 is driven toward one electrode 31 by driving the pressure shaft 35. The electrodes 31 and 32 are disposed so as to face each other. That is, the workpiece can be held between the electrodes 31 and 32 by driving the pressurizing shaft 35 by the servo motor and reducing the distance between the electrode 31 and the electrode 32. And it can spot-weld by supplying with electricity to each electrode 31 and 32 in the state which pinched | interposed the workpiece | work between the electrodes 31 and 32. FIG.
A shank 36 is formed at the tip of the arm 33 to which the electrode 31 is attached. The shank 36 is formed in a tapered shape that is inclined with respect to the axis of the electrode 31. As shown in FIG. 3, the inside of the shank 36 is formed hollow. The servo motor is driven and controlled by a control signal from the control device 5 and can drive the arm 23 of the robot.

(Imaging device)
As shown in FIG. 1, the imaging device 4 is connected to a camera 41 that captures an image of a welding point of a workpiece, an attachment portion 42 provided between the spot welding gun 3 and the camera 41, and the attachment portion 42. , And a protection unit 43 that covers at least a part of the camera 41.
(1) Attachment part As shown in FIG. 3, the attachment part 42 is formed in the cylinder shape, and is attached to the shank 36 of the front-end | tip of the spot welding gun 3 so that attachment or detachment is possible. The attachment portion 42 is formed with a tapered insertion hole 42 a that fits into the tapered shank 36 for attachment to the shank 36. The attachment portion 42 can be fixed to the shank 36 together with the protection portion 43 by hitting with a hammer or the like, like the electrode 31. By attaching the attachment portion 42 to the shank 36, the tip of the shank 36 is shielded.
As shown in FIGS. 3 and 4, on the surface of the mounting portion 42, a fitting portion 42b for fitting a tool such as a spanner to stably hold the mounting portion 42 when being attached to or detached from the shank 36. Is formed. The fitting portion 42b is a concave portion that is recessed with respect to the surface of the mounting portion 42 formed in a curved surface, and the bottom surface of the concave portion is formed to be a flat surface. Thereby, even if tools, such as a spanner, are fitted in fitting part 42b, a tool does not slip and it can hold attachment part 42 in the stable state.
The protection part 43 is connected to the end part of the attachment part 42 opposite to the end part to be attached to the shank 36 by a connection screw 47.

(2) Protection part As shown in FIG. 3, one end of the protection part 43 is formed in an elliptical shape or a rectangular shape, and a passage hole 43a through which light emitted from the light source 44 provided in the protection part 43 passes. Is formed. By forming the passage hole 43a, it is possible to irradiate light onto the workpiece that is irradiated from the light source 44 and disposed between the electrode 32 and the camera head 45 (described later).
Here, the light source 44 is attached to the inner wall surface of the protection part 43 by a jig 44 a. One light source 44 may be provided as long as it can irradiate the work with a sufficient amount of light, but a plurality of light sources 44 may be provided within a space allowed.

(3) Camera As shown in FIG. 2, as the camera 41, for example, a small CCD camera is used. The camera 41 is detachably provided to at least one of the two electrodes 31 and 32. At this time, the camera 41 is provided such that its optical axis is coaxial with the axis A of the electrode 32. Here, the axis A of the electrode 32 refers to an axis parallel to the moving direction of the electrode 32, passing through the welding point of the workpiece during spot welding (where the workpiece and the electrode 32 are in contact). FIG. 2 shows an example in which the electrode 31 fixed to the arm 33 and the camera 41 are exchanged.
As shown in FIGS. 1 and 3, the camera 41 includes a camera head 45 having an imaging element and a lens for forming an image of a workpiece welding point, and a processing unit 46 for processing an image formed by the camera head 45. And. The camera head 45 is fixed to the mounting portion 42 with fixing screws 49, and the periphery thereof is covered with a protection portion 43. Here, only the camera head 45 is provided in the protection unit 43, and only the camera head 45 is covered by the protection unit 43. The processing unit 46 is provided at a position away from the spot welding gun 3 by the communication cable 46a. Thereby, the imaging by the camera head 45 can be remotely operated, and the size of the protection unit 43 can be reduced.

The processing unit 46 stores a CPU 61 that executes image processing according to a processing program related to a captured image captured by the camera head 45, a RAM 62 that is a work area of the CPU 61, an image processing program and various data, and is rewritable and nonvolatile. A camera interface 64 connected to be able to receive captured image data between the memory 63 and the camera head 45, and a communication interface connected to be able to send and receive image processing data and various data between the control device 5. 65.
The non-volatile memory 63 stores an image processing program that performs image processing of a captured image captured by the camera head 45. That is, when the CPU 61 executes the image processing program, the processing unit 46 functions as an image processing unit.

(Control device)
As shown in FIG. 1, the control device 5 stores a CPU 51 that executes each process according to a processing program related to operation control of the robot 2, a RAM 52 that is a work area of the CPU 51, a work program of the robot 2, and various data. The rewritable nonvolatile memory 53, the robot body axis servo driver 54 that drives the robot 2, the pressure axis servo driver 55 that drives the pressure axis 35 of the spot welding gun 3, and the processing unit 46. And a communication interface 56 connected so as to be able to transmit and receive data.

  As shown in FIG. 1, the non-volatile memory 53 of the control device 5 stores a work program taught to perform a welding operation on the robot 2 and the spot welding gun 3. Accordingly, the nonvolatile memory 53 functions as a storage unit. Moreover, when the CPU 51 executes the work program, the control device 5 functions as a control unit that controls the operation of the robot 2 and the spot welding gun 3.

<How to attach / detach the imaging device to / from the spot welding gun>
As shown in FIGS. 3 and 4, when attaching the imaging device 4 to the spot welding gun 3, after fixing the camera head 45 to the attachment portion 42, the camera head 45 is covered with the protection portion 43, and the attachment portion 42 The protection part 43 is connected to the connection screw 47. Then, the shank 36 of the spot welding gun 3 is inserted into the insertion hole 42a of the mounting portion 42 and the protective portion 43 is hit with a hammer, or the pressure shaft 35 is driven to bring the electrode 32 and the protective portion 43 into contact with each other. Thus, the attachment portion 42 is fixed by being inserted into the shank 36. After the attachment portion 42 is fixed to the shank 36, the shank 36 and the attachment portion 42 are tapered, and thus cannot be easily detached.
On the other hand, when removing the mounting portion 42 fixed to the shank 36, a tool such as a spanner is fitted to the fitting portion 42b of the mounting portion 42, and the tool is operated while the mounting portion 42 is stably held by the tool. By doing so, the attaching part 42 can be removed from the shank 36.

<Operational effects of imaging device and spot welding robot system>
Thus, according to the spot welding robot system 1 including the imaging device 4 and the imaging device 4, at least the camera head 45 that is a part of the camera 41 is covered by the protection unit 43. When attaching to the gun 3, the camera head 45 can be attached to the spot welding gun 3 together with the protection part 43 without damaging the camera head 45 by hitting the protection part 43 even when tapping with a hammer.
Further, since the attachment portion 42 is provided between the shank 36 of the spot welding gun 3 and the camera head 45, the camera head 45 is indirectly attached to the spot welding gun 3 via the attachment portion 42. It will be. Thereby, even if the cooling water is circulated in the shank 36, the water is applied to the mounting portion 42, so that the cooling water is not applied to the camera head 45, and a failure due to a short circuit of the electric circuit of the camera head 45 is prevented. Can do.

The light emitted from the light source 44 provided in the protection unit 43 diffuses to the surroundings. However, since the protection unit 43 has a passage hole 43a, the light is emitted from the light source 44 and the electrode 32. Light traveling toward the workpiece provided between the camera head 45 passes through the passage hole 43a and jumps out of the protective portion 43 to irradiate the workpiece.
This makes it possible to accurately capture the workpiece even when imaging a portion where a large amount of light is required, such as the inside of the workpiece.

  In addition, since only the camera head 45 of the camera 41 is provided so as to be covered with the protection unit 43, the size of the protection unit 43 is larger than when both the camera head 45 and the processing unit 46 are covered with the protection unit 43. Since the size of the portion of the camera 41 provided on the spot welding gun 3 can be made closer to the size of the electrode 32, the effect of preventing the interference between the camera 41 and the workpiece can be enhanced. .

  Moreover, since the fitting part 42b is formed in the surface of the attachment part 42, when attaching or detaching the imaging device 4 to the spot welding gun 3, tools, such as a spanner, can be easily fitted and the imaging device 4 is attached. Can be attached to and detached from the spot welding gun 3 while being held in a stable state.

<Others>
The present invention is not limited to the above embodiment. For example, in the above embodiment, a C-type spot welding gun is used as the spot welding gun, but an X-type spot welding gun may be used.
Further, the processing unit 46 is provided in the imaging device 4. If the control device 5 has an image processing function, the control device 5 wirelessly transmits an image captured by the camera head 45 to the control device 5. Image processing can be performed and the robot 2 can be controlled based on the data. These configurations can be freely changed according to the requests of workers and designers.
Further, instead of forming the passage hole 43a in the protection portion 43, the entire protection portion 43 may be formed of a light transmissive material. In this case, of course, it is necessary to have such strength that it is not damaged by an external force when attached to the shank 36.

The figure which shows schematic structure of a spot welding robot system provided with an imaging device. The front view of a spot welding gun. (A) is a sectional view taken along the line aa in FIG. 4, and (b) is a sectional view taken along the line bb in FIG. The perspective view of an attaching part and a protection part. The figure explaining the attachment structure of an electrode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Spot welding robot system 2 Robot 3 Spot welding gun 4 Imaging device 5 Control apparatus (control means)
22 Joint 31 Electrode 32 Electrode 41 Camera 42 Mounting part 42b Fitting part 43 Protection part 43a Passing hole 44 Light source 45 Camera head 46 Processing part 53 Non-volatile memory (storage means)
A Axis of electrode

Claims (5)

Provided at the tip of a robot having a plurality of joints, provided to be exchangeable with one electrode of a spot welding gun having two electrodes arranged opposite to each other, and provided so that the optical axis is coaxial with the axis of the electrode In an imaging device for imaging an image of a welding point of a workpiece by the electrode,
A camera that captures an image of a welding point of the workpiece;
An attachment part provided to be interposed between the two when attaching the camera to the spot welding gun;
A protection unit that covers the camera head of the camera , which is connected to the mounting unit and has an imaging element and a lens that form an image of a welding point of the workpiece ;
Equipped with a,
The image pickup apparatus according to claim 1, wherein the protection part is provided with a passage hole for allowing light to pass through or the entire protection part is formed of a light-transmitting material . A light source that is covered by the protection unit and that irradiates light to the surroundings;
The passage hole of the protection unit, the imaging apparatus according to claim 1, wherein the passing light toward the workpiece disposed between the camera is illuminated with the other electrode from the light source. The camera includes the camera head, and a processing unit that processes an image formed by the camera head,
The imaging apparatus according to claim 1, wherein only the camera head is provided so as to be covered with the protection unit.   The fitting part which fits a tool in the case of the attachment or detachment of the said attachment part to the said spot welding gun is formed in the surface of the said attachment part. The imaging device described. A robot having a plurality of joints;
A spot welding gun provided at the tip of the robot and having two electrodes disposed opposite to each other;
An imaging device that is provided so as to be exchangeable with one of the electrodes, is provided so that an optical axis is coaxial with the axis of the electrode, and images an image of a welding point of the workpiece by the electrode; and
Storage means for storing a work program taught to perform a welding operation on the robot and the spot welding gun;
In a spot welding robot system comprising: control means for controlling operation of the robot and the spot welding gun according to a work program stored in the storage means;
The imaging device
A camera that captures an image of a welding point of the workpiece;
An attachment part provided to be interposed between the two when attaching the camera to the spot welding gun;
A protection unit that covers the camera head of the camera , which is connected to the mounting unit and has an imaging element and a lens that form an image of a welding point of the workpiece ;
Equipped with a,
The spot welding robot system , wherein the protection part is provided with a passage hole for allowing light to pass through, or the entire protection part is formed of a light-transmitting material .

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