JP2013255972A - Workpiece conveying device and method for controlling the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve positional detection accuracy when recognizing a position of a workpiece by a camera, in an articulated robot.SOLUTION: A workpiece 13 in a container 11 is conveyed to a processing chamber 50 by an articulated robot 20. The camera 23 for photographing the workpiece 13 and detecting the position thereof is mounted on an arm 25 of the articulated robot 20. When the posture of the workpiece 13 mounted on a liner 12 of the container 11 is tilted, the position of the workpiece 13 can not be detected in some cases as the workpiece 13 can not be fully focused even though the camera 23 photographs it from vertically upper side. When such a situation occurs, a control device 100 controls arms 21, 22 and the arm 25 to change the posture of the camera 23 for photographing so that a picture image with smaller inclination relative to the workpiece 13 is obtained and the position detection can be performed. This improves the positional detection accuracy of the workpiece without providing any special mechanism.

Description

  The present invention relates to a technique for conveying a workpiece by an articulated robot.

Articulated robots are used to remove workpieces, that is, products to be processed in factories, etc., from containers before processing, transport them to processing chambers, etc., and store processed workpieces in containers. There is. In this case, since the articulated robot recognizes and holds the position of the workpiece, a camera may be used.
Patent Document 1 discloses a technique for recognizing a work target with a camera attached to a robot hand. Patent Document 2 discloses a technique for three-dimensionally recognizing a work target based on a plurality of pieces of image data taken while a camera is translated.

JP-A-5-204423 JP-A-6-10603

In general, the workpiece before transport is often stored in a container or the like, but is not necessarily stored accurately in a posture and position that can be easily grasped by the articulated robot. When the container containing the workpiece is set in the movable range of the articulated robot, the position and posture of the workpiece may be shifted. Further, when the work is stacked and accommodated in multiple layers in the container via the insole, the position and posture of the work may deviate from the original state due to bending of the insole.
If an articulated robot tries to pick up a workpiece without recognizing such a deviation, the workpiece may not be gripped sufficiently and may fall off, or the workpiece may get caught in the container or insole when taken out. As a result, other workpieces in the container may be damaged.
In order to avoid such trouble, it is necessary to accurately detect the position in consideration of the posture of the workpiece.
However, if a special apparatus such as a three-dimensional vision camera is used in order to consider the posture of the workpiece, a new problem that the cost becomes too high is caused.
The present invention has been made in view of the above problems, and an object of the present invention is to improve the position detection accuracy when recognizing the position of a workpiece using a camera in an articulated robot.

The present invention
A workpiece transfer device for transferring a workpiece,
An articulated robot, and a control unit for controlling the articulated robot,
The articulated robot is:
An arm that extends from the base and is articulated,
A hand attached to the tip of the arm and gripping the workpiece;
A camera attached to the arm and imaging the workpiece;
The controller is
Controlling the arm and sequentially changing the camera to a plurality of preset postures to image the workpiece, detecting the position of the workpiece based on the imaging result, and gripping the workpiece; It can be configured as a work transfer device that controls the hand.

According to the present invention, it is possible to accurately detect the position of a workpiece even when the workpiece is deviated from the original posture by sequentially changing the camera to a plurality of postures and capturing images.
Further, the articulated robot can freely move the position of the arm. In the present invention, since the camera is attached to the arm, the posture of the camera can be easily changed by controlling the arm. . Therefore, according to the present invention, it is possible to obtain an improvement effect of detection accuracy at a low cost without newly providing a special mechanism for changing the posture of the camera.
In the present invention, the camera can be attached to any position of the arm, but is preferably attached to a position away from the hand, for example, a position across the indirect from the hand. By doing so, when the articulated robot moves the hand in order to grip the workpiece, the camera can be prevented from being hindered, and the operating efficiency can be improved.
Imaging in a plurality of postures can be performed by various procedures. For example, it is also possible to use the one that has obtained the best result by detecting the position after imaging in a plurality of preset postures. As another method, a method of repeatedly performing imaging and detection, that is, a method of performing imaging with a certain posture and detecting a position, and performing imaging and detecting a position with the next posture when detection accuracy is insufficient. It may be taken. The latter method has an advantage that unnecessary shooting can be avoided.

In the present invention,
When the workpiece has a substantially axial target shape,
The control unit may detect the position of the workpiece using the imaging result in which a ratio of a focused portion is a predetermined value or more.
When the posture of the work with respect to the camera is relatively inclined, an image in which a portion focused by the camera and a portion other than that are mixed is captured. Therefore, the position detection accuracy can be evaluated by detecting the ratio of the in-focus portion of the workpiece image. According to the above aspect, the detection accuracy can be evaluated by such a relatively simple method, and the control processing load can be reduced.
The predetermined value for evaluating the detection accuracy can be arbitrarily set.

In the present invention,
A cleaning mechanism for cleaning the lens of the camera within a movable range of the arm;
The control unit may retry the imaging and detection after cleaning the lens by the cleaning mechanism when the position of the workpiece cannot be detected in a predetermined number of postures.
The reason why the position of the workpiece cannot be detected is not only that the posture of the workpiece is tilted but also that the lens is dirty. If the lens of the camera is cleaned as in the above embodiment, the reason why the position cannot be detected is limited to the tilt of the workpiece, so that it is possible to quickly detect the position without repeating unnecessary imaging.
The timing for interposing the cleaning can be arbitrarily set based on statistical data or the like where position detection is normally performed.

The above-described cleaning mechanism can have various configurations, for example,
The cleaning mechanism is a mechanism in which a wiping portion for wiping off dirt on the lens is supported by an elastic member,
The control unit may control the arm so that the lens is rubbed against the wiping unit during the cleaning.
Lens wiping is the simplest and most effective cleaning method. According to the above aspect, there is an advantage that cleaning can be realized by controlling the arm without providing a special device. Moreover, in the said aspect, since the wiping part is supported by the elastic member, the elastic member can absorb the pressure at the time of rubbing a lens on a wiping part, and it can avoid that a lens is damaged easily.
As the cleaning mechanism, a mechanism for blowing a gas such as compressed air to the lens after wiping by the wiping unit and blowing away fine fibers of the wiping unit may be provided.

Regardless of whether or not a cleaning mechanism is provided, in the present invention,
The workpiece before conveyance is accommodated in a recess formed by opening on a flexible insole,
The control unit may be configured to control the workpiece to be lifted upward from the concave portion after the workpiece is held from above by the hand and the posture of the workpiece is inclined by a predetermined angle from the vertical direction. Good.
When the workpiece is accommodated in the flexible insole, depending on the position and posture of the workpiece, a part of the workpiece may be biting into the side wall of the recess. In such a case, if the work is lifted up as it is, the work may catch the insole and damage other insole. According to the said aspect, since it inclines before lifting a workpiece | work, it can be made to release from the state which the workpiece | work bites into the insole by this operation | movement, and the failure | damage etc. of another workpiece | work can be avoided.
The tilt angle of the workpiece can be arbitrarily set according to the type of the workpiece, the operating environment, etc. so that the above-mentioned trouble does not occur.

Also,
The workpiece transfer device is for storing the workpiece after transfer in a workpiece storage insole having a recess formed by opening upward,
The control unit may perform control to release the holding of the workpiece in a state where the arm holding the workpiece is placed in the concave portion with a predetermined angle from the vertical direction.
When the workpiece transfer destination is a workpiece storage insole having a recess, it is necessary to accurately store the workpiece in the recess. When the work is tilted by a predetermined angle as in the above-described aspect, a part of the work is easily accommodated in the recess relatively smoothly, and as a result, the accommodation efficiency of the entire work can be improved.
The tilt angle of the workpiece can be arbitrarily set according to the type of the workpiece, the operating environment, etc. so that the above-mentioned trouble does not occur.

In the present invention,
When the work has a vertical through-hole,
The work before transport is housed in a predetermined insole,
The articulated robot includes a rod mechanism that projects a rod extending through the through hole when the work is held by the hand,
The controller may control the rod to protrude when the workpiece is held by the hand and lifted from the insole.
As a workpiece having a vertical through-hole, for example, a workpiece having a cylindrical portion can be considered.
If the work is in close contact with the insole with oil or the like, or if it is biting into the insole, when the work is lifted, there is a risk of damaging the other work that has been housed by shifting the insole. According to the said aspect, since a workpiece | work and an insole can be reliably separated by making a rod protrude, such a trouble can be avoided.
Various timings can be set for projecting the rod, but it is desirable to project at least when lifting the rod from the insole.

Moreover, when the workpiece conveyance device of the present invention is for conveying the workpiece into a processing chamber filled with mist,
The articulated robot has a gas blowing unit that blows gas onto the lens of the camera,
The control unit may perform control so that gas is blown from the gas blowing unit when transported into the processing chamber.
Mist refers to a state in which oil, water, dust, etc. are mist-like. When transported into the processing chamber filled with such mist, dirt is likely to adhere to the camera lens. According to the said aspect, by blowing gas on a lens, the mist around a lens can be blown off and adhesion of dirt can be suppressed. As the gas to be blown, any gas such as air or nitrogen can be selected.

The present invention is not limited to the above-described aspect of the workpiece transfer device, and can take various forms.
For example,
An articulated robot having an arm extending from a base and connected by a multi-joint, a hand attached to a tip of the arm and gripping the work, and a camera attached to the arm and imaging the work. A control method for controlling a workpiece transfer device for transferring
(A) controlling the arm and detecting the position of the workpiece based on an imaging result obtained by imaging the workpiece with a preset posture of the camera;
(B) If the position of the workpiece is not detected, performing the step (a) by sequentially changing the camera to a plurality of postures;
(C) Based on the detected position of the workpiece, it may take a form of a control method for a workpiece transfer device including a step of controlling the arm and the hand so as to hold the workpiece.
In this case, it is also possible to apply various features described in the workpiece transfer device together.

  In addition, the present invention may be configured as a computer program for controlling the work transfer device by a computer. Moreover, you may comprise as a computer-readable recording medium which recorded such a computer program. Recording media include flexible disks, CD-ROMs, magneto-optical disks, IC cards, ROM cartridges, punch cards, printed matter on which codes such as bar codes are printed, internal storage devices of computers (memory such as RAM and ROM), and Various media that can be read by a computer, such as an external storage device, can be used.

It is explanatory drawing which shows the whole structure of an apparatus. It is explanatory drawing which shows the structure of a hand periphery. It is explanatory drawing which shows the structure of the mechanism with which the articulated robot periphery was equipped. It is explanatory drawing which shows the functional block of a control apparatus. It is explanatory drawing which shows the principle of the position detection of a workpiece | work. It is a flowchart of a workpiece conveyance control process. It is a flowchart of a container / insole transfer process. It is a flowchart of a work position detection process. It is explanatory drawing which shows the sequence of a camera attitude | position. It is a flowchart of a workpiece removal process.

A. Device configuration:
A1. overall structure:
Hereinafter, an embodiment of a workpiece transfer apparatus using a vertical articulated robot will be described.
FIG. 1 is an explanatory diagram showing the overall configuration of the apparatus. This is an apparatus for taking out a workpiece from the carry-in side container storage 10A and transporting it to the processing chamber 50, then taking out the processed workpiece from the processing chamber 50 and transporting it to the carry-out side container storage 10B.

  The state of the workpiece | work accommodated in the container 11 placed in 10 A of carrying-in side container storage places was shown in the lower right of the figure. As shown in the figure, the workpiece 13 to be conveyed in the present embodiment is a component that is a shaft target, and has a shape in which a cylindrical portion and a disc-shaped flange portion are combined. This is an example of the shape of the workpiece 13, and may be a workpiece other than a shaft target component or a component having a cylindrical portion.

In the container 11, the workpieces 13 are stacked in multiple stages via the insole 12. The insole 12 is a resin sheet and is provided with a recess for accommodating the workpiece 13. The insole 12 is prepared according to the type of the work 13. Further, the insole 12 has such a degree of rigidity that is necessary for stacking the work 13 in multiple stages without damaging it, and the posture of the work 13 may be inclined from the vertical direction due to flexibility.
The container 11 and the insole 12 placed in the carry-in side container storage 10A are moved to the discharge side container storage 10B after all the workpieces 13 are taken out. The processed workpieces 13 are stacked in multiple stages in the container 11 via the insole 12 and discharged, as in the case of carrying in.

In the figure, the insole transfer device 40 is shown on the carry-in side container storage 10A and the carry-out side container storage 10B. Although not shown in order to avoid complication of the drawing, the insole transfer device 40 is supported by a rail so as to be movable in the direction of arrow F. As will be described later, suction cups are provided at four locations on the lower surface of the apparatus, and the insole 12 can be adsorbed.
In the carry-in side container storage 10A, the workpieces 13 are sequentially taken out from the containers 11. When the top of the insole 12 becomes empty, the insole transfer device 40 moves onto the container 11 and sucks and moves the insole 12 with a suction cup. By doing so, the workpiece transfer device can take out the workpiece 13 at the lower stage of the insole 12 that has become empty.
Conversely, in the carry-out side container storage 10B, when the processed workpieces 13 are fully loaded on the insole 12, the insole transfer device 40 transfers the insole 12 collected in the carry-in side container storage 10A. . By doing so, since the empty insole 12 is placed on the full work 13, the next processed work 13 can be accommodated thereon.

In the center of the apparatus, an articulated robot 20 for conveying a workpiece is installed. The articulated robot is an industrial robot having a known structure in which the arms 21, 22, 25 and the hand 24 are connected by joints. The arm 21 is attached to a base portion (in the shadow of a cleaner 30 described later in the drawing), and can rotate around a vertical axis as indicated by an arrow A. The arm 22 is connected to the arm 21 and is rotatable as indicated by an arrow B. The arm 25 is attached to the tip of the arm 22 and swings as indicated by an arrow C. A hand 24 for gripping a workpiece is attached to the tip of the arm 25.
By the movement of the arms 21, 22, and 25 described above, the articulated robot 20 can move the hand 24 up and down as shown by an arrow E at an arbitrary location.
Two hands 24 are attached to the tip of the arm 25 and are rotatable as indicated by an arrow D. By carrying out like this, while an unprocessed workpiece | work can be conveyed to the processing chamber 50 with one hand 24, the processed workpiece | work can be taken out from the processing chamber 50 with the other vacant hand 24, and operating efficiency is improved. Can do.

A camera 23 is attached to the arm 25. The camera 23 is a digital camera for capturing a two-dimensional still image. In the present embodiment, as will be described later, the work in the container 11 is photographed by the camera 23 and the position thereof is detected, whereby the work can be gripped and conveyed.
Further, as will be described later, in this embodiment, the ratio of the in-focus portion in the image captured by the camera 23 is used to determine whether or not position detection is appropriate. Therefore, it is preferable that the camera 23 has a relatively narrow depth range, and in this sense, a longer focal length is preferable.

The processing chamber 50 can be, for example, a working chamber that performs cutting or polishing by a machine. The inside of the processing chamber 50 is filled with oil and dust at the time of processing like mist (hereinafter also referred to as “mist”).
The processing contents in the processing chamber 50 are for convenience of explaining the embodiments, and in applying the present invention, the processing contents in the processing chamber 50 are not limited to cutting or polishing. . In applying the present invention, the inside of the processing chamber 50 does not need to be filled with mist, the processing chamber 50 is omitted, and the workpiece transfer device simply transfers the workpiece from a predetermined location to another location. You may comprise as an apparatus only for the purpose to do.

The cleaner 30 is a mechanism for cleaning the lens of the camera 23. Although the structure of the cleaner 30 will be described later, it includes a wiping unit for wiping the lens and a mechanism for blowing air onto the lens.
In addition to the cleaner 30, as will be described later, a device for blowing air onto the lens is attached to the camera 23 as a mechanism for preventing contamination of the lens portion of the camera 23. When the hand 24 is inserted into the processing chamber 50, air is blown onto the lens to prevent mist from adhering to the lens. The attachment site of this device will be described later.
Air for spraying the cleaner 30 and the camera 23 is supplied from an air compressor 60.

The operation of each device described above is controlled by the control device 100. The control device 100 is a computer having a CPU, a ROM, and a RAM inside, and controls each device according to a control program. Examples of the control target include the articulated robot 20, the air-compressor 60, the insole transfer device 40, the processing chamber 50, and the like.
The configuration of the control program and the contents of the control process will be described later.

A2. Configuration around the hand:
FIG. 2 is an explanatory diagram showing a configuration around the hand.
FIG. 2A shows an enlarged perspective view of the vicinity of the hand 24 and the camera 23. As described with reference to FIG. 1, two hands 24 are attached, and one hand can be used for unloading a workpiece from the processing chamber 50 and the other for loading the workpiece into the processing chamber 50. As illustrated, the camera 23 is provided with a lens 23L and an air outlet 23b. Although not shown, a pipe for sending air from an air compressor (see FIG. 1) is connected to the air outlet 23b.

  FIG. 2B schematically shows a side view. The air outlet 23b blows out air (portion indicated by fine hatching in the drawing) to the lens 23L of the camera 23. By doing so, an air curtain can be formed on the surface of the lens 23L, and mist can be prevented from adhering to the lens 23L during loading / unloading into the processing chamber 50.

The hand 24 is provided with a gripping portion 24a that opens and closes so as to grip the workpiece from the outside. The gripping portion 24a is not limited to such a structure, and may be a mechanism that grips the cylindrical portion from the inside by being expanded after being inserted into the cylindrical portion of the workpiece.
A rod 24 b is attached to the center of the hand 24. The rod 24b has a shape in which a disk is attached to the tip of a rod-shaped member, and moves up and down as indicated by arrows in the drawing. The rod 24b is accommodated in the hand 24 when gripping and transporting the workpiece, and protrudes as shown when the workpiece is taken out from the container.
By doing so, the workpiece can be taken out while holding the insole with the rod 24b. If the insole is in close contact with the workpiece, when the workpiece is taken out, the insole may be lifted together with the workpiece and cause damage to other workpieces remaining on the insole. You can avoid these problems by holding down the floor.
As a mechanism for operating the rod 24b, for example, a mechanism that electromagnetically operates using a solenoid, a mechanism that operates using hydraulic pressure or air, and the like can be applied. If it is a use which presses an insole, since the big load will not be applied to the rod 24b, the mechanism operated electromagnetically is comparatively simple and highly useful.
In the present embodiment, one of the two hands 24 is used as the hand 24 dedicated to taking out the workpiece from the container, and therefore the rod 24b is provided only on one side. If any of the hands 24 is used for taking out a workpiece, it is preferable to provide both of them.
The rod 24b is a mechanism for reliably separating the workpiece and the insole. Instead of the rod 24b, the compressed air may be blown out in the direction in which the rod 24b protrudes (from the top to the bottom in the figure).

A3. Peripheral structure:
FIG. 3 is an explanatory diagram showing a configuration of a mechanism provided around the articulated robot.
FIG. 3A is a perspective view of the cleaner 30. The cleaner 30 is a mechanism for removing dirt on the lens of the camera attached to the articulated robot. The cleaner 30 is provided with a wiping portion 32 and an air blowing portion 34 in the main body 31.
The wiping portion 32 is a part having a cloth for wiping the lens on the surface, is supported on the surface by a spring 33, and moves up and down according to pressure from above. By controlling the arm of the articulated robot and rubbing the lens of the camera against the wiping unit 32, dirt on the lens can be wiped off. As described above, since the wiping unit 32 moves up and down, damage to the lens can be avoided even if the force of the articulated robot pressing the lens against the wiping unit 32 becomes excessive. .
The air blowing part 34 is a mechanism for blowing out compressed air from the air compressor. When the lens is wiped off by the wiping unit 32, there is a possibility that fiber waste or the like may adhere to the lens. Therefore, by blowing air from the air blowing unit 34 to the lens, such dirt can be blown off. In this embodiment, after the articulated robot rubs the lens on the wiping unit 32, the lens is moved to the upper side of the air blowing unit 34, so that air is blown out to remove dirt attached to the lens. .

FIG. 3B shows the configuration of the insole transfer device 40. In the insole transfer device 40, suction cups 42 are attached to the lower surfaces of four corners of a rectangular main body 41. As shown in the drawing, the suction cup 42 has a shape in which three trapezoidal cone-shaped resin cups are connected in a bellows shape. Due to this shape, the cup is deformed so that a degree of freedom is generated in the direction of the opening portion of the suction cup. Has the advantage that it can be adsorbed.
A drain pipe 43 is connected to the suction cup 42. The drain pipe 43 is used to collect oil adhering to the surface of the insole with the drain pipe 43 when adsorbing the insole with the suction cup.

A4. Control unit configuration:
FIG. 4 is an explanatory diagram showing functional blocks of the control device. The control device 100 is configured by a computer. Therefore, each functional block shown in the figure is configured by software by installing a computer program for control. A part or all of each functional block may be configured in hardware.

The main control unit 101 integrates overall control of each device described with reference to FIGS. Parameters necessary for control are stored in the control parameter database 102. Examples of stored parameters include the type of workpiece and insole.
The operation control unit 110 includes the functional blocks shown in the figure, and controls the other operations of the articulated robot.
The arm / hand drive control unit 111 controls the operations of the arms 21, 22, 25, the hand 24, the rod 24 b and the like of the articulated robot 20. The container / insole transfer mechanism drive control unit 112 controls the operation of the insole transfer device 40 and the mechanism for transferring the empty container. The camera control unit 113 controls photographing with the camera 23. The processing chamber control unit 114 controls processing performed inside the processing chamber 50. The air compressor control unit 115 controls on / off of air blowing from the air compressor 60.
The work position detection unit 120 detects the position of the work based on the image taken by the camera control unit 113. A method for analyzing the position will be described later. The detection result of the workpiece position is used for workpiece gripping / conveyance control. If the position cannot be detected, the main control unit 101 retries position detection via the arm / hand drive control unit 111 and the camera control unit 113 as described later.
The lens cleaning control unit 130 has a function of cleaning the lens 23L of the camera 23. This cleaning is performed in the process of retrying position detection. The lens cleaning control unit 130 also has a function of giving an instruction to the air compressor control unit 115 so as to blow air onto the lens 23L when the work is carried into and out of the processing chamber 150.
The conveyance operation control unit 140 controls the gripping / conveying / carrying out of the workpiece and accommodation in the insole 12 based on the workpiece position detected by the workpiece position detecting unit 120. For example, the movement of the hand to a position for gripping the workpiece is realized by the transfer operation control unit 140 issuing an instruction to the arm / hand drive control unit 111. In addition, the operation of the hand for gripping the workpiece, the protrusion of the rod during gripping, and the like are the same. When the insole 12 becomes empty, the transport operation control unit 140 outputs an instruction to the container / insole transfer mechanism drive control unit 112 to move the insole. The control content of the transport operation will be described later.

B. Work position detection:
Next, a method for detecting the position of the workpiece will be described.
FIG. 5 is an explanatory view showing the principle of workpiece position detection. A state in which the workpiece is imaged by the camera 23 with the vertically upward posture Aa and the slightly oblique posture Ab is shown. It is assumed that the workpiece is slightly tilted from vertically above due to bending of the insole 12 or the like.
The image Pa is an imaging result from a vertically upward posture Aa. The hatched part on the left represents the part that is not in focus. When the work is inclined obliquely, in this state, since the work is inclined relative to the camera 23, only a part of the work is focused as shown in the image Pa. In the image Pa, the left half is hatched to schematically show a portion out of focus, but in practice, the focus shift sequentially changes according to the distance of the work from the camera 23, and in a certain region Therefore, the image is so unclear that it is not acceptable. The hatched portion in the figure is a region that is unclear beyond the allowable range.
On the other hand, the image Pb is shown in the image taken from the oblique posture Ab. The image Pb has no hatched portion. This indicates that the entire subject is in focus. In the posture Ab, since both the workpiece and the camera 23 are tilted, the relative tilt of both is small, and thus an image that is focused as a whole can be taken. Thus, according to the image focused entirely, the center position C can be specified with high accuracy by image analysis. The process of specifying the center of the circular image can be realized by a relatively well-known and easy image processing technique.
Even in the case of using the camera 23 that performs two-dimensional imaging in this way, it is possible to capture an image suitable for position detection by changing the imaging posture according to the tilt of the workpiece. In the present embodiment, the position of the workpiece is detected with high accuracy using such a principle.

C. Work transfer control processing:
Below, the content of the control process for conveying a workpiece | work is demonstrated. This process is a process realized by each functional block (see FIG. 4) of the control apparatus 100, and is a process executed by the CPU of the control apparatus 100 based on a computer program in terms of hardware.

C1. Work transfer control processing:
FIG. 6 is a flowchart of the workpiece transfer control process. This process corresponds to a process for controlling the operation of the entire workpiece transfer apparatus, and mainly corresponds to a function of the main control unit 101 shown in FIG.
First, the control device 100 executes a container / insole transfer process (step S10), a workpiece position detection process (step S20), and a workpiece removal process (step S30). The container / transfer process is a process of transferring the empty container 11 and insole 12. The workpiece position detection process is a process for detecting the position of the workpiece based on the principle described with reference to FIG. The workpiece removal processing is processing for removing the workpiece from the insole 12. Specific contents of each processing will be described later.

Next, the control device 100 executes a control process for bringing the workpiece into the processing chamber 50. First, in order to prevent the mist from adhering to the lens 23L of the camera 23, the air blow to the lens 23L is turned on (step S40), and in this state, the work is carried into the processing chamber 50 (step S41).
Then, the processed workpiece is removed from the processing chamber 50, and a new workpiece is installed (step S42). As described with reference to FIGS. 1 and 2, in this embodiment, two hands 24 are provided. In this process, the processed workpiece is first gripped by the hand 24 not gripping the workpiece, and then a new workpiece gripped by the other hand 24 is set. By doing this, it is possible to efficiently remove and install the work, avoiding the trouble of once taking the processed work in the container and then taking out the new work from the container and transporting it to the processing chamber. Become.
The control device 100 leaves the processing chamber while holding the processed workpiece, and when the exit is completed, turns off the air blow to the lens 23L of the camera 23 (step S43).
Then, the work is placed at a specified position of the insole for discharge, that is, the insole in the container installed in the carry-out side container storage 10B, and released (step S44). The specified position is a place where the work is not yet placed in the recess of the insole.
When placing the workpiece, the control device 100 lowers the workpiece while holding the workpiece in a slightly tilted state, gently grounds the insole, and then releases the workpiece. In this case, the inclination angle may be in the range of several degrees from the vertical.
By tilting in this way, there is an effect that the workpiece can be stably accommodated in the recess. For example, consider a case where the position where the workpiece is lowered is slightly shifted from the recess of the insole. If the workpiece is lowered without being inclined, the bottom surface of the workpiece hits the periphery of the recess, and therefore the control device 100 may erroneously recognize that the workpiece is grounded on the insole and release the workpiece. On the other hand, when the work is inclined, the projected area on the insole is reduced according to the inclination angle, so that even if the position is slightly shifted, it can be easily accommodated in the recess of the insole. The tilt angle of the workpiece may be set according to the expected value of the position error between the workpiece and the recess, taking this effect into account.
By repeatedly executing the above processing, the workpiece transfer device can sequentially transfer the workpieces to the processing chamber 50 and store the processed workpieces in the container of the unloading side container storage 10B. Next, specific contents of each of the above-described steps S10 to S30 will be described.

C2. Container / insole transfer processing:
FIG. 7 is a flowchart of the container / insole transfer process. This is a process corresponding to step S10 of the workpiece transfer control process (FIG. 6).
The control device 100 determines whether there is a work to be taken out from the carry-in side container storage 10A (step S11). This determination can be easily made by counting the number of workpieces that have been transferred after transferring the insole. The insole may be photographed with the camera 23 to determine whether or not the work remains.
When the work remains (step 11), it is determined that there is no need to transfer the container and the insole, and the control device 100 ends the container / insole transfer process.

If no workpiece remains, the control device 100 next determines whether or not the container 11 is empty (step S12). Whether or not the container 11 is empty can be easily determined by counting the number of insoles that have been transferred after the workpiece has been transported. Alternatively, the insole may be photographed with the camera 23, and a determination may be made based on whether or not the existence of a workpiece can be confirmed below the insole.
When it is determined that the container 11 is empty, the control device 100 executes a transfer process for the container 11 (step S13). In this embodiment, the container 11 is transferred from the carry-in side container storage 10A to the carry-out container storage 10B. Since the mechanism for transferring the container 11 is a well-known technique, description thereof is omitted.

  When the work remains in the container 11, the control device 100 performs a process for transferring the insole 12. For this reason, the insole 12 is adsorbed by the suction cup 42 of the insole transfer device 40 (step S14) and moved (step S15). The insole transfer device 40 has suction cups 42 attached to the four corners (see FIG. 3). However, since the insole 12 has a different recess position for each type, any of the suction cups 42 may be recessed. May hit you. Therefore, the control device 100 operates by changing the suction cup 42 used for suction according to the type of the insole 12. Instead of always operating the four suction cups 42, two or three suction cups 42 that do not hit the recesses are operated depending on the insole 12, and different suction cups 42 are operated in the case of another insole 12. To do. By doing so, it is possible to perform stable adsorption on a wide variety of insoles 12.

  In the present embodiment, a drain pipe 43 is attached to the suction cup of the insole transfer device 40. Therefore, the oil on the insole can be recovered through the drain pipe 43 by the action of the suction cup in step S14.

C3. Work position detection processing:
FIG. 8 is a flowchart of the workpiece position detection process. This is a process corresponding to step S20 of the workpiece transfer control process (FIG. 6).
First, the control device 100 moves the arm to the specified position (step S21). Since the number and arrangement of works on the insole are determined in advance according to the type of work, the position of the work to be taken out next is also determined. The specified position refers to a position determined in this way.
When the arm is moved, the control device 100 controls the posture of the camera 23 and performs shooting (step S22). In the present embodiment, as described with reference to FIG. 5, the center position of the workpiece is obtained based on the focused portion in the image obtained by photographing the workpiece. Therefore, the control device 100 determines whether or not it is an appropriate shooting result based on whether or not the ratio of the focused portion of the image shot in step S22 exceeds a predetermined reference value. (Step S23).
The reference value for determination can be arbitrarily set, for example, 70% or more. The reference value may be a fixed value or a value that varies depending on the type of workpiece.
When it is determined that the image is appropriate (step S23), the control device 100 detects the position of the workpiece based on the image (step S24). In this embodiment, as shown in FIG. 5, the center position of the workpiece is obtained by image processing. The position detection method is not limited to this, and various methods can be used.

When it is determined that the ratio of the in-focus portion is lower than the reference value and is not an appropriate image (step S23), until the third time (step S25), the control device 100 changes the posture of the camera 23. Then, shooting is attempted again (step S22). A sequence for changing the posture will be described later.
When it is determined that the image is not an appropriate image for the third time (step S25), the control device 100 determines that the cause is other than the posture of the workpiece, that is, the contamination of the camera 23, and performs the lens wiping process. Execute (step S26). In this process, the control device 100 controls the arm to rub the lens 23L portion of the camera 23 against the wiping portion 32 of the cleaner 30. In this way, the dirt on the lens 23L can be easily removed.
Due to this wiping, the fine fibers of the wiping portion 32 may adhere to the lens 23L, and thus the control device 100 executes air blow to the lens 23L (step S27). In this process, the control device 100 controls the arm to bring the lens 23L portion of the camera 23 closer to the air blowing portion 34 of the cleaner 30 and blows air from the air blowing portion 34 to blow off the fine fibers.
After the camera 23 has been cleaned in this way, the camera 23 is changed in posture again and shooting is attempted (step S22).
Through the above processing, the control device 100 can detect the position of the workpiece.

FIG. 9 is an explanatory diagram showing a camera posture sequence. FIG. 9A is a perspective view showing the shooting position of the camera around the workpiece. In this embodiment, the work is photographed from nine locations P1 to P9. The photographing position P1 represents a state where the work is photographed from vertically above. If the workpiece is normally placed facing vertically upward, an appropriate image should be taken at the shooting position P1. The photographing positions P2 to P9 are positions obtained by dividing a circle centered on the vertical axis corresponding to the photographing position P1 into eight equal parts in the horizontal plane. In the case of the photographing position P2, as shown in the drawing, the photographing is performed obliquely facing the direction of the work. The other shooting positions are also shot in the same manner from the eight diagonal directions.
In the present embodiment, since the position of the work is generally determined by the recess provided in the insole, the posture of the photographing positions P2 to P8 is set as described above assuming that the work is at this position. Can do. The radius R of the circle that defines the photographing positions P2 to P8 may be determined so that an appropriate image can be photographed according to variations in the position and posture of the work in the insole. The reason why the camera is photographed in various postures is to enable photographing from a direction where the relative inclination with respect to the workpiece is sufficiently small as shown in FIG. If the radius R is too small, the change in the posture of the camera becomes small and a posture suitable for photographing cannot be obtained. Conversely, if the radius R is too large, the posture change of the camera becomes excessive, and a posture suitable for photographing cannot be obtained. As described above, it is desirable that the radius R that determines the posture of the camera is determined by testing, analysis, or the like as an appropriate value corresponding to the variation in the posture of the workpiece.
The radius R may be a fixed value or a different value depending on the type of workpiece. In the present embodiment, the photographing positions P2 to P9 are set on the same plane, but may be set three-dimensionally. In order to accurately determine the suitability of the photographing result, it is preferable to unify the distance between the camera and the workpiece at all photographing positions. From this viewpoint, the photographing positions P1 to P9 are on the same spherical surface centered on the workpiece. It is also preferable to set to.
In addition, since the workpieces are stacked in multiple stages in the container 11, the position of the workpiece whose position is to be detected changes. Considering these points, the shooting position may be set so that the relative posture between the workpiece and the camera is always constant. According to this aspect, as the lower work is handled in the container 11, the camera position is gradually lowered downward. As another aspect, the shooting height of the camera may be fixed. In this aspect, in order to maintain the angle at which the workpiece is photographed at each of the photographing positions P2 to P9, the radius R that determines the photographing position of the camera is gradually increased as the lower workpiece is handled.

FIG. 9B schematically shows a sequence of shooting positions of the camera. Small circles in the figure represent the photographing positions P1 to P9 shown in FIG. 9A, and ● represents the position at which photographing is performed.
As shown in the upper left of FIG. 9B, shooting is first performed at a shooting position P1 vertically above. If an appropriate photographing result cannot be obtained at this position, photographing is performed at the photographing position P2. Further, if it is not appropriate, photographing is performed at a photographing position P6 that faces the photographing position P2. Images may be taken in order like the shooting positions P2 and P3, but if it is determined that the shooting result is not appropriate, it is more likely that an appropriate result will be obtained if the posture of the camera is greatly changed. Because.
If an appropriate result is not obtained at the shooting position P6, as shown by the solid line arrow, the lens cleaning is performed, and then shooting is resumed. In this embodiment, after taking an image again at the photographing position P1, photographing is performed after the unphotographed photographing position P4. This is because, if the reason why the proper image cannot be obtained by the previous photographing is the dirt of the lens, there is a high possibility that an appropriate image can be obtained at the photographing position P1 from vertically above.
A sequence in which lens cleaning is omitted may be set. In this case, shooting is performed at a shooting position P4 that has not been shot after the shooting position P6 (broken arrow in the figure). Further, the lens cleaning does not necessarily have to be performed after the photographing at the three positions is completed, and may be performed at another timing.
Thereafter, as in the shooting positions P4 and P8, shooting is performed by sequentially changing the shooting positions while pairing the shooting positions facing each other. In this process, lens cleaning may be further performed.

C4. Work removal processing:
FIG. 10 is a flowchart of the workpiece removal process. This is a process corresponding to step S30 of the workpiece transfer control process (FIG. 6).
The control device 100 moves the hand to the workpiece detection position (step S31). Then, the work is gripped and held tilted (step S32). The state of tilt holding is shown in the figure.
The left side shows a state where the workpiece is held in a vertical posture. When the position of the work is slightly deviated from the center of the recess of the insole, if it is gripped in a vertical posture, a part of the work bites into the side wall of the insole recess as shown in the region A in the figure May be. If the workpiece is taken out in this state, the insole is lifted together with the workpiece, and there is a possibility that other workpieces placed on the insole may be damaged.
On the right side, the workpiece is tilted and held. By tilting in this manner, even if a part of the work bites into the insole recess, the biting can be released. What is necessary is just to set arbitrarily the angle which inclines a workpiece | work so that this effect may be acquired. In this embodiment, it has been confirmed that the effect can be obtained at several degrees.

  After tilting the workpiece in this way, the control device 100 takes out the workpiece while protruding the separating rod 24b (step S33). The state of the rod 24b is shown in the figure. The rod 24b is accommodated in the hand, but when the workpiece is taken out, the rod 24b operates in the direction of the arrow in the figure and protrudes from the hand. Since the workpiece of the present embodiment is a cylindrical member at the center, the rod 24b can penetrate the hollow portion of the workpiece and hold the insole. By doing so, it is possible to avoid lifting the insole together with the workpiece when taking out the workpiece, and it is possible to avoid damaging other workpieces placed on the insole.

  According to the work conveyance device of the embodiment described above, the position of the work can be detected with high accuracy by photographing the work by changing the posture of the camera 23 in various ways. In addition, since an articulated robot is used, the control of the posture of the camera 23 does not need to be provided with a special mechanism, and there is an advantage that it can be easily realized by controlling the arm.

  The various features described in the embodiments are not necessarily all provided, and can be applied by appropriately omitting or combining some of the features. The present invention is not necessarily limited to the above-described embodiments, and can be applied to various configurations.

  The present invention can be used to accurately detect the position of a workpiece with a camera and transport the workpiece using an articulated robot.

DESCRIPTION OF SYMBOLS 10A ... Carrying side container storage place 10B ... Carrying out side container storage place 11 ... Container 12 ... Insole 13 ... Work 20 ... Articulated robot 21, 22, 25 ... Arm 23 ... Camera 23b ... Air outlet 23L ... Lens 24 ... Hand 24a ... Grasping part 24b ... Rod 30 ... Cleaner 31 ... Main body 32 ... Wiping part 33 ... Spring 34 ... Air blowing part 40 ... Insole transfer device 41 ... Main body 42 ... Suction cup 43 ... Drain pipe 50 ... Processing chamber 60 ... Air compressor DESCRIPTION OF SYMBOLS 100 ... Control apparatus 101 ... Main control part 102 ... Control parameter database 110 ... Operation control part 111 ... Arm / hand drive control part 112 ... Container / insole transfer mechanism drive control part 113 ... Camera control part 114 ... Processing room control part 115: Air compressor control unit 120 ... Work position detection unit 130 ... Lens cleaning system Control unit 140 ... Conveyance operation control unit

Claims (9)

A workpiece transfer device for transferring a workpiece,
An articulated robot, and a control unit for controlling the articulated robot,
The articulated robot is:
An arm that extends from the base and is articulated,
A hand attached to the tip of the arm and gripping the workpiece;
A camera attached to the arm and imaging the workpiece;
The controller is
Controlling the arm and sequentially changing the camera to a plurality of preset postures to image the workpiece, detecting the position of the workpiece based on the imaging result, and gripping the workpiece; Work transfer device that controls the hand. It is a workpiece conveyance apparatus of Claim 1, Comprising:
The workpiece has a substantially axial object shape,
The said control part is a workpiece conveyance apparatus which detects the position of the said workpiece | work using the said imaging result whose ratio of the part which is focusing is more than predetermined value. It is a workpiece conveyance apparatus of Claim 1 or 2, Comprising:
A cleaning mechanism for cleaning the lens of the camera within a movable range of the arm;
When the position of the workpiece cannot be detected in a predetermined number of postures, the control unit retryes the imaging and detection after cleaning the lens by the cleaning mechanism. It is a workpiece conveyance apparatus of Claim 3, Comprising:
The cleaning mechanism is a mechanism in which a wiping portion for wiping off dirt on the lens is supported by an elastic member,
The said control part is a workpiece conveyance apparatus which controls the said arm so that the said lens may be rubbed against the said wiping part in the case of the said cleaning. It is a workpiece conveyance apparatus in any one of Claims 1-4,
The workpiece before conveyance is accommodated in a recess formed by opening on a flexible insole,
The said control part hold | maintains the said workpiece | work from the upper direction with the said hand, Then, it inclines the attitude | position of this workpiece | work by only the predetermined angle from the perpendicular direction, The workpiece conveyance apparatus which controls to lift this workpiece | work upward from the said recessed part. It is a workpiece conveyance apparatus in any one of Claims 1-5, Comprising:
The workpiece transfer device is for storing the workpiece after transfer in a workpiece storage insole having a recess formed by opening upward,
The said control part is a workpiece conveyance apparatus which controls so that the holding | maintenance of this workpiece | work may be released in the state which inclined only the predetermined angle from the perpendicular direction in the said arm which hold | maintained the said workpiece | work. It is a workpiece conveyance apparatus in any one of Claims 1-6, Comprising:
The workpiece has a vertical through-hole,
The work before transport is housed in a predetermined insole,
The articulated robot includes a rod mechanism that projects a rod extending through the through hole when the work is held by the hand,
The said control part hold | maintains the said workpiece | work with the said hand, and it is controlled so that the said rod may protrude when it lifts from the said insole. It is a workpiece conveyance apparatus in any one of Claims 1-7,
The workpiece transfer device is for transferring the workpiece into a processing chamber filled with mist,
The articulated robot has a gas blowing unit that blows gas onto the lens of the camera,
The said control part is a workpiece conveyance apparatus which controls so that gas may be sprayed from the said gas spraying part, when conveying in the said process chamber. An articulated robot having an arm extending from a base and connected by a multi-joint, a hand attached to a tip of the arm and gripping the work, and a camera attached to the arm and imaging the work. A control method for controlling a workpiece transfer device for transferring
(A) controlling the arm and detecting the position of the workpiece based on an imaging result obtained by imaging the workpiece with a preset posture of the camera;
(B) If the position of the workpiece is not detected, performing the step (a) by sequentially changing the camera to a plurality of postures;
(C) A method for controlling a workpiece transfer device, comprising: controlling the arm and the hand so as to grip the workpiece based on the detected position of the workpiece.

Images