JP3658680B2 - Monitoring device and remote monitoring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a monitoring device that monitors a work situation, and more particularly, to a remote monitoring device that can be used in a bad environment such as a welding process in which a substance such as spatter or fume or radiant heat is generated.
[0002]
[Prior art]
Japanese Patent Laid-Open No. 8-150475 describes a welding status remote monitoring device that images the state of a weld pool, an arc, and a groove during welding. In this device, an interference filter that transmits light having a center wavelength of 600 to 800 nm and a wavelength width of 100 nm or less is disposed on the front surface of the CCD camera, and is suitable for each of the above-described objects by a control device that selects and switches the shutter speed. Images are captured at the shutter speed, and the images of the objects are combined and displayed by the image processing apparatus, thereby enabling welding condition control including groove line copying.
[0003]
Japanese Patent Laid-Open No. 8-25040 discloses an infrared light generating means for irradiating a welded portion, a monitoring camera for photographing a welded portion provided with an infrared light transmitting filter that transmits only infrared light, and an output from the monitoring camera. A system for monitoring the welding state is shown, which includes a monitor for outputting a video signal.
[0004]
Japanese Laid-Open Patent Publication No. 2-303679 describes that a light-reducing glass is arranged in a front and rear direction of the camera so as to cope with a large luminance difference between welding and non-welding.
[0005]
[Problems to be solved by the invention]
In order to obtain a clear image, it is necessary to adjust the amount of light incident on the CCD or the like according to the luminance of the observation target. Therefore, in the above-described conventional apparatus, when an object with high luminance is imaged, light incident on the CCD is inserted by inserting a filter or a light reducing glass that transmits light in a specific range of wavelengths into the optical axis of the camera. The amount of is decreasing.
[0006]
However, the brightness of observation objects with high brightness, such as arc light or molten pool, is not constant, but varies with time or with welding conditions. In the above-described prior art device, it is impossible to always make the optimal amount of light incident on the CCD in response to such a variation in luminance, and a sufficiently clear image cannot be obtained.
[0007]
An object of the present invention is to obtain a clear image at all times even if the range of change in luminance of an observation object is large and the luminance varies depending on time and environment.
[0008]
[Means for Solving the Problems]
The above-described problems include a camera body having an imaging lens, a filter that transmits light in a specific wavelength range, and light that travels along the optical axis by inserting and removing the filter from the optical axis of the imaging lens. A first actuator that changes the amount in two stages, two polarizing plates that are arranged on the optical axis and transmit linearly polarized waves in a specific polarization direction, and the polarizing transmission axis of one polarizing plate is the other A second actuator that adjusts the amount of light that is rotated with respect to the polarization transmission axis of the polarizing plate and that travels along the optical axis, a third actuator that moves the imaging lens along the optical axis, and components thereof The first to third actuators are arranged symmetrically around the optical axis, and the base plate is connected to a cooling member having a cooling water channel. From the cooling member. It is solved by a monitoring device, characterized in that transmits cold heat to the component and the housing through the scan plate.
[0009]
According to this monitoring device, by inserting / removing the filter to / from the optical axis, the amount of light incident on the imaging lens is adjusted in two stages, and further, the angle formed by the polarization axes of the two filters is changed, The amount of light incident on the imaging lens can be continuously finely adjusted. Therefore, by using this monitoring device, even if the luminance of the observation object changes greatly, an appropriate amount of light can be instantaneously incident on the imaging lens, and the luminance of the observation object can be reduced. Even if it fluctuates, it can follow this.
[0010]
If the third actuator for moving the imaging lens along the optical axis is provided, a clear image can be obtained that is accurately focused. Moreover, if a means for supplying a sealing gas and a cooling fluid is provided inside the housing of the monitoring device, it can be used in a harsh environment such as a welding process.
[0011]
The above monitoring device, and means for controlling the position of the monitoring device so that the position of the specific monitoring object in the image obtained by the monitoring device matches a predetermined position in the image The remote monitoring device can automatically place the position of the camera at a position where the observation object can be best observed, and can be used, for example, for remote monitoring of the welding process.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a schematic configuration diagram of an embodiment of the monitoring apparatus of the present invention. The monitoring device includes a CCD camera 1, a base 2 to which the CCD camera 1 is attached, a cylindrical housing 3, a water-cooling cooling member 4, and a cover 5 having an opening (not shown) in the center. The A transparent optical window 6 such as heat resistant glass is integrally attached to the cover 5. The housing 3 is attached to the base 2 via a heat conductive packing 11. Further, the cover 5 is attached to the housing 3 through a similar packing 12. The base 2 is provided with an injection hole 13 for injecting a gas such as air, CO 2, or Ar in order to seal the inside of the housing from the outside. The CCD camera includes an imaging lens 7 disposed in front, a first polarizing plate 8 attached integrally with the imaging lens 7, a bandpass filter 9 that transmits only light in a specific wavelength range, A polarizing plate 10 is provided.
[0013]
FIG. 2 is a plan view of the cooling member 4 as viewed from the direction of the arrow M in FIG. A cooling water inlet 14 and a cooling water drain 15 are provided on the rear surface of the cooling member 4. Water passages 13A, 13B, and 13C are provided inside the cooling member. The end of the water channel 13B is closed by a lid 16. The CCD camera is controlled by a signal sent from the outside via the control signal cable 1a. The gas injection hole 13 on the base 2 side communicates with the gas injection hole 17 on the cooling member side. The cooling member 4 is provided with through holes 18 and 19 for fixing the base 2. On the base 2 side facing the two through holes, screw grooves are respectively provided (not shown). By flowing cooling water through the cooling member 4, the cooling member 4 is cooled, and the base 2 and the CCD camera 1 are cooled by heat transfer from the contact surface between the cooling member 4 and the base 2.
[0014]
FIG. 3 is a diagram showing an orthogonal cross section at an arbitrary position on the central axis (Z) line of the cylindrical casing 3 shown in FIG. In this figure, the same elements as those in FIG. A first DC motor 21, a second DC motor 22, and a third DC motor 23 are disposed around the optical axis.
[0015]
The imaging lens 7 of the remote monitoring apparatus of this embodiment can be moved in the optical axis direction of the CCD camera by an actuator. Hereinafter, this mechanism and its operation will be described with reference to FIG. FIG. 4 is a cross-sectional view of the cylindrical housing 3 in the direction indicated by BB ′ in FIG. 3, and shows a bandpass filter rotating mechanism and a polarizing plate rotating mechanism, which will be described later, omitted. In FIG. 4, the first DC motor 21 is fixed to the base 2 without contact with the imaging lens 7 (not shown). The linear actuator 24 is composed of a ball screw and a roller guide, and the slide table 24b moves straight by the rotation of the rotating shaft 24a. The supports 25 and 26 of the linear actuator 24 are fixed to the base 2. The V pulley 27 is integrally attached to the rotating shaft 24a. A first polarizing plate is integrally attached to the tip of the imaging lens 7 via a ring 28, and these are further attached to an angle 29. The angle 29 is fixed to the slide table 24b. On the other hand, a V pulley 31 is integrally attached to the rotating shaft of the first DC motor 21. The rotational motion of the V pulley 31 is transmitted to the rotational motion of the V pulley 27 by the belt 32. That is, the imaging lens 7 can linearly move on the observation optical axis of the CCD camera by the forward and reverse rotational movements of the first DC motor 21.
[0016]
Since the focal position of the observation image changes due to the linear movement of the imaging lens 7, even if the relative distance between the target object and the CCD camera changes for some reason, it is not necessary to readjust the CCD camera mounting position. The focus position can be easily adjusted while watching a monitor TV or the like that remotely displays the image of the CCD camera.
[0017]
FIG. 5 is a cross-sectional view of the cylindrical housing 3 in the direction indicated by CC ′ in FIG. 3, omitting the linear motion mechanism of the imaging lens 7 and a polarizing plate rotation mechanism described later. is there. In FIG. 5, a holder 33 provided with a band pass filter 9 is integrally attached to the rotating shaft of the second DC motor 22. The supports 34 and 35 of the second DC motor 22 are fixed to the base 2.
[0018]
FIG. 6 shows the structure of the holder 33. In FIG. 6, the fan-shaped holder 33 is provided with two openings for the center M. The band pass filter 9 is mounted only on one opening side. When the second DC motor 22 is rotated to the left in the figure, the bandpass filter 9 is disengaged from the observation axis (center of the figure) of the CCD camera, and is further rotated to indicate the fan-shaped center by the symbol N When the rotation stops at the position, the aperture 33a coincides with the observation axis of the CCD camera. Positioning of the stop after the rotation of the holder 33 is performed by a limit switch, for example (not shown). With the above mechanism, the band pass filter 9 can be set or removed on the front surface of the observation optical axis of the CCD camera by the rotation and positioning of the second DC motor 22.
[0019]
When performing a welding operation remotely using a CCD camera, it is necessary to accurately align the tip of the welding torch with the groove position to be welded before starting welding. Also, during welding, it is monitored whether the welding torch tip is correctly positioned at the groove position and welding is being performed, and when a malfunction occurs, the mechanism system to which the welding torch is attached is operated. Correct the target position of the tip of the welding torch. Furthermore, the welding quality is ensured by confirming whether or not defects have occurred in the beads after welding. In such observation, it is necessary to repeat the removal and attachment of the bandpass filter before the start of welding, during welding, and after the end of welding. However, according to the configuration of the present invention, this operation is easily performed by remote control. be able to.
[0020]
FIG. 7 is a cross-sectional view of the cylindrical housing 3 in the direction indicated by AA ′ in FIG. 3, and omits the linear motion mechanism and the band-pass filter rotation mechanism of the imaging lens 7 described above. . In FIG. 7, a gear 36 is integrally attached to the rotation shaft of the third DC motor 23. The supports 37 and 38 of the third DC motor 23 are fixed to the base 2. The gear 36 is engaged with a gear 40 that is rotatably attached to the center axis of the plate 39. The second polarizing plate 10 is integrally attached to the inside of the gear 40. As the third DC motor 23 rotates, the polarizing plate 10 rotates about the observation optical axis of the CCD camera.
[0021]
The polarizing plate is made of a material that substantially transmits one of two linearly polarized light having polarization planes orthogonal to each other and hardly transmits the other. Accordingly, the amount of light transmitted through the first polarizing plate and the second polarizing plate is the smallest when the polarization transmission axes of the two polarizing plates make an angle of 90 ° with each other. When the first polarizing plate is fixed and the second polarizing plate is rotated from the state where the transmitted light amount is the smallest, the transmitted light amount gradually increases, and reaches the maximum transmitted light amount at 0 ° (or 180 °). That is, by rotating the second polarizing plate, it is possible to continuously change the brightness of the image observed by the CCD camera. This makes it possible to adjust the brightness of an image obtained by a CCD camera, for example, to be constant even if the brightness of an observation object changes due to a change in welding conditions such as a welding current during welding in a welding operation or the like. It becomes possible.
[0022]
FIG. 8 is a schematic configuration diagram of a welding system using the monitoring device of the present invention. This system controls the position of a consumable welding electrode (hereinafter abbreviated as an electrode) 41 such as a tungsten electrode, as well as an electrode 41, welded members 44 and 45, and a welding groove (hereinafter referred to as a welding bead including a weld bead). 43) When the arc generating portion 46 at the tip of the electrode is imaged by the monitoring device 50 of the present invention, the position of the monitoring device 50 is controlled to obtain a clear image.
[0023]
The monitoring device 50 is disposed on the welding progress direction side, and observes (images) the molten pool and the non-consumable electrode from diagonally forward of the groove. The monitoring device includes a control circuit 51 that controls the CCD camera and outputs an analog video (image) signal to the outside, a CCD camera imaging position control circuit 47 that uses the first DC motor 21, and a second DC motor 22. And a second polarizing plate rotation control circuit 49 using the third DC motor 23.
[0024]
The system includes an electrode position control mechanism 54. The electrode position control mechanism 54 includes an X traveling shaft 55, an X traveling carriage 56 traveling on the X traveling axis, a Z traveling shaft 57 integrally disposed on the X traveling carriage 56, and the Z traveling axis. Z traveling carriage 58, Y traveling shaft 59 integrally disposed on Z traveling carriage 58, and Y traveling carriage 60 traveling on the Y traveling axis.
[0025]
The electrode 41 is disposed integrally with the Y traveling carriage 60 (not shown), and drives the electrode position control mechanism 54 so that the weld line direction: X, the weld line orthogonal direction: Y, and the vertical direction above the groove 45. Direction: Can move in Z direction. Similarly to the electrode 41, the monitoring device is also mounted on the X traveling carriage 56 and includes a movable shaft (not shown) that can move freely in the X and Y directions separately from the movable shaft of the electrode 41.
[0026]
The system further includes an image processing device 52, and the image processing device A / D converts an analog image signal output from the camera control circuit 51 into a digital quantity and inputs multivalued image data. A multi-value image storage unit for storing multi-value image data, an image feature amount extraction processing unit for extracting the welding electrode tip position and the center position of the weld pool from the multi-value image data stored in the multi-value image storage unit; The calculation unit processing unit detects a positional deviation between the welding electrode tip position and the center position of the molten pool from the screen reference position, and a main control unit that comprehensively controls these. The TV monitor 53 outputs and displays the output video signal from the camera control circuit 51 and the processing result from the image processing apparatus.
[0027]
The system further includes an electrode position control device 61 that drives and controls the electrode position control mechanism 54, a welding power source 62, and a monitoring device position control device 63 that controls the movement of the monitoring device 50 in the X and Y directions.
[0028]
The image processing device 52, the electrode position control device 61, the monitoring device position control device 63, and the welding power source 62 described above are centrally controlled by an overall control device 64 constituted by a personal computer or the like. The overall control device 64 has a function of preliminarily storing the scanning target position of the electrode in each welding pass with respect to the member to be welded for performing multi-layer welding, and an electrode position and an electrode target position shift obtained from the image processing device 52 The welding line scanning control function for outputting the amount of movement of the electrode from the information to the electrode position controller 61, and the amount of movement of the monitoring device from the screen position shift information of the electrode tip obtained from the image processing device 52 to the monitoring head position controller 63 It has a welding line scanning control function. Furthermore, storage of groove reference shapes such as groove depth, groove angle, step difference, etc., storage of welding plan data such as the number of welding passes, reference welding current for each pass, voltage, welding speed, wire feed speed, etc. It is possible to correct these data before starting welding or before starting welding in each welding pass.
[0029]
FIG. 9 is a schematic diagram of a weld pool and electrode image obtained by imaging with a CCD camera in the case of welding with a narrow groove shown in FIG. The high part is expressed as black and the dark part (low brightness) is expressed as white. FIG. 9 shows an electrode image 65, a molten pool image 66, an arc image 67, groove wall images 44 and 45, and an image 44a of the boundary region between the groove bottom portion and the groove slope portion in the groove wall portion. 44b, images 45a and 45b of the boundary region between the groove slope surface and the groove surface in the groove wall portion are shown.
[0030]
The groove walls 44 and 45 also have high brightness when illuminated by arc light during welding. FIG. 9 shows a case where the tip 65a of the electrode image 65 is observed shifted from the screen center point O to the upper left, that is, there is a relative positional shift between the observation optical axis center and the groove center of the CCD camera. It shows a case.
[0031]
Although the inclination angle of the groove slope portion of the member to be welded shown in FIG. 8 is the same, the width of the groove wall portion 45 in the image is narrow and the width of the groove wall portion 44 is It is getting wider. If this deviation further increases, the groove wall 45 disappears from the screen and the right side of the molten pool image 66 is missing. If it becomes like this, it will become difficult to make a welding electrode follow the groove bottom center correctly, and it will lead to the fall of welding quality.
[0032]
In the image of FIG. 9, the arc image 67 is usually the brightest, and is subsequently captured as a bright image in the order of the molten pool image 66 and the electrode image 65. Based on the brightness difference between the images, the electrode image is first extracted, and then the coordinates (i1, j1) of the electrode tip are obtained. Then, the difference from the observation reference point (i0, j0) on the screen is calculated, and this difference is taken as the positional deviation of the CCD camera. A stable image can be acquired by using this positional shift information and sequentially correcting and controlling the camera position using the monitoring device position control device 63. The observation reference point (i0, j0) may be the screen center O (i = 0, j = 0), but is not limited thereto. In the above description, the scanning control of the camera is performed based on the positional deviation of the welding electrode tip. However, the scanning control may be performed using the center position of the molten pool. By making the scanning control of the monitoring device independent from the scanning control of the welding electrode with respect to the welding line, it is possible to always monitor a good welding phenomenon.
[0033]
The monitoring apparatus described above includes a CCD camera body, a base to which the CCD camera body is attached, a housing having an optical window attached to the base and a cover on the front surface, and has a structure that blocks the CCD camera body from outside air. is there. Further, by injecting a gas such as air from the gas inlet into the housing, it is possible to increase the internal pressure and seal from the outside. As a result, since spatters such as welding and fumes do not enter the inside, the built-in components are not contaminated. In addition, when a structure that integrally attaches a cooling member that is cooled by cooling water to the base to which the CCD camera is attached and the housing that covers the entire case is used, it receives radiant heat from a high-temperature welding member But it has excellent durability. The monitoring device of the present invention can be used not only in arc welding work but also in adverse environments where high temperatures, dirt, etc. are generated such as laser welding, cutting work, and plasma cutting work.
[0034]
【The invention's effect】
According to the present invention, it is possible to obtain a clear image at all times even if the range of change in luminance of the observation object is large and the luminance varies depending on time and environment.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an embodiment of a monitoring device of the present invention.
FIG. 2 is a plan view of a cooling member of the apparatus of FIG.
3 is a cross-sectional view orthogonal to the central axis of the device of FIG.
FIG. 4 is a diagram showing an imaging lens linear movement mechanism of the apparatus of FIG. 1;
FIG. 5 is a view showing a band-pass filter rotation mechanism of the apparatus of FIG. 1;
6 is a view showing a holder structure of the apparatus of FIG. 1; FIG.
7 is a view showing a polarizing plate rotating mechanism of the apparatus shown in FIG.
FIG. 8 is a schematic configuration diagram of a welding system using the monitoring device of the present invention.
FIG. 9 is a schematic diagram of a molten pool and electrode image captured by a CCD camera.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 CCD camera 2 Mounting base 3 Case 4 Cooling member 5 Cover 6 Optical window 7 Imaging lens 8 1st polarizing plate 9 Band pass filter 10 2nd polarizing plate 14 Cooling water inlet 15 Cooling water drain 17 Gas injection Hole 21 First DC motor 22 Second DC motor 23 Third DC motor 24 Linear actuator 27 V pulley 29 Angle 31 V pulley 32 Belt 33 Holder 36 Gear 40 Gear 41 Consumable welding electrode 43 Welding groove 44 Welded Member 45 Welded member 46 Arc generator 47 CCD camera imaging position control circuit 48 Filter switching control circuit 49 Polarizing plate rotation control circuit 50 Monitoring head 51 CCD camera control circuit 52 Image processing device 53 TV monitor 54 Electrode position control mechanism 55 X Traveling axis 56 X traveling cart 57 Z traveling shaft 58 Z traveling cart 59 Y traveling 60 Y traveling carriage 61 electrode position controller 62 welding power source 63 monitors head position control device 64 the overall control unit 65 electrode image 66 melt pool image 67 arc image 68 groove wall image 69 groove wall image

Claims (3)

A camera body having an imaging lens, a filter that transmits light in a specific wavelength range, and an amount of light that travels along the optical axis by inserting / removing the filter to / from the optical axis of the imaging lens. A first actuator to be changed to two, two polarizing plates arranged on the optical axis and transmitting linearly polarized waves in a specific polarization direction, and a polarizing transmission axis of one polarizing plate to a polarization of the other polarizing plate Contains a second actuator that rotates relative to the transmission axis and adjusts the amount of light traveling along the optical axis, a third actuator that moves the imaging lens along the optical axis, and the components Is integrally attached to the base plate,
The first to third actuators are arranged symmetrically around the optical axis, and the base plate is connected to a cooling member having a cooling water channel, so that the cooling plate is connected to the cooling plate through the base plate. A monitoring device that transmits cold heat to a component and the housing . The base plate, the monitoring device according to claim 1, characterized in that it comprises in the interior of the housing, the gas injection holes for supplying the sealing gas. The position of the monitoring apparatus according to claim 1 or 2 , and the position of the monitoring apparatus so that a position of a specific object in the image obtained by the monitoring apparatus matches a predetermined position in the image And a remote monitoring device.

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