JP7283881B2 - work system - Google Patents

Description

This specification discloses a working system.

Conventionally, by applying vibration to a supply section such as a conveying path on which the work is placed, the work is conveyed in a predetermined direction, or the work is unraveled in a state of being overlapped to supply the work. is disclosed (see, for example, Patent Document 1).

JP 2018-127301 A

When the robot picks up the work supplied by the work supply device described above, the work is picked up after waiting for a predetermined period of time, which is expected for the work to stand still after the end of applying vibration to the supply unit, to pick up the work. It is conceivable to start However, if the predetermined time is set to a short time, the robot may pick up the work while the work is still moving, and picking errors are likely to occur. On the other hand, if the predetermined time is set to a long time to prevent picking errors, it will take a long time to pick up a large number of works, leading to a decrease in work efficiency. Moreover, it is difficult to appropriately set the predetermined time for a work whose posture is difficult to stabilize, such as a cylindrical work.

A main object of the present disclosure is to efficiently and appropriately pick up supplied workpieces.

The present disclosure has taken the following means to achieve the above-mentioned main objectives.

A work system according to the present disclosure is a work system in which a robot picks up a plurality of works supplied to a supply unit and performs a predetermined work, comprising: an imaging device that images the plurality of works on the supply unit; a control device for controlling the robot so as to obtain the amount of change in a plurality of images captured by the device, determine whether the work is stationary based on the convergence of the amount of change, and then pick up the work; ,
The gist is to provide

The work system of the present disclosure determines that the work on the supply unit is stationary based on the convergence of the amount of change in the plurality of images, and then controls the robot to pick up the work. As a result, it is possible to properly pick up the workpiece by preventing the robot from making a mistake in picking up the workpiece due to the movement of the workpiece. In addition, as in the case of setting the waiting time until the start of picking up the supplied work, frequent picking mistakes due to short waiting time and the decrease in work efficiency due to long waiting time are avoided. can be prevented. Therefore, the supplied work can be efficiently and appropriately picked up.

1 is a configuration diagram showing an outline of the configuration of a work system 10; FIG. FIG. 2 is a configuration diagram showing an outline of the configuration of a work conveying device 20; FIG. 2 is a partial external view of the work conveying device 20 as seen from the back side; FIG. 4 is an explanatory diagram showing the electrical connection relationship of the control device 70; FIG. 4 is an explanatory view showing how the bulky piled state of the workpieces W is unraveled. 4 is a flow chart showing an example of a collection and placement control routine; FIG. 4 is an explanatory diagram showing how the work W stands still; 10 is a flowchart showing a pick-and-place control routine of a modified example;

Next, embodiments for implementing the present disclosure will be described with reference to the drawings.

FIG. 1 is a configuration diagram showing an outline of the configuration of the work system 10, FIG. 2 is a configuration diagram showing an outline of the configuration of the work conveying device 20, and FIG. , and FIG. 4 is an explanatory diagram showing the electrical connection relationship of the control device 70. As shown in FIG. 1 and 2, the horizontal direction is the X-axis direction, the front-rear direction is the Y-axis direction, and the vertical direction is the Z-axis direction.

The work system 10 of this embodiment is a system that places the works W accommodated in the supply box 12 on the tray T in an aligned state. The work system 10 includes a tray transport device 16, a work transport device 20, a supply robot 40, and a collection robot 50, as shown in FIG. These are installed on the workbench 11 . The work performed by the work system 10 is not limited to the work of placing the work W on the tray T, and may include an assembly work of assembling the work W to a predetermined object.

The tray conveying device 16 has a pair of belt conveyors that are stretched in the left-right direction (X-axis direction) with an interval in the front-rear direction (Y-axis direction). The tray T is conveyed from left to right by a belt conveyor.

The supply robot 40 is a robot for taking out the works W as various parts such as mechanical parts and electric parts from the supply box 12 and supplying them to the supply area A1 (see FIG. 2) of the work transfer device 20 . The supply robot 40 includes a vertically articulated robot arm 41 and an end effector 42 . The robot arm 41 includes a plurality of links, a plurality of joints that rotatably or pivotally connect the links, a drive motor 44 (see FIG. 4) that drives the joints, and an encoder 45 (see FIG. 4) that detects the angles of the joints. See FIG. 4). The plurality of links includes a distal link to which end effector 42 is attached and a proximal link that is fixed to workbench 11 . The end effector 42 can hold and release the work W. The end effector 42 can use, for example, a mechanical chuck, a suction nozzle, an electromagnet, or the like, and supplies the workpieces W in bulk to the supply area A1.

The picking robot 50 is a robot for picking up the works W in the picking area A2 (see FIG. 2) of the work conveying device 20, transferring them onto the tray T, and aligning them. The collection robot 50 includes a vertically articulated robot arm 51 and an end effector 52 . The robot arm 51 includes a plurality of links, a plurality of joints that rotatably or pivotally connect the links, a drive motor 54 (see FIG. 4) that drives the joints, and an encoder 55 (see FIG. 4) that detects the angles of the joints. See FIG. 4). The plurality of links includes a distal link to which end effector 52 is attached and a proximal link that is secured to workbench 11 . The end effector 52 can hold and release the work W. For the end effector 52, for example, a mechanical chuck, a suction nozzle, an electromagnet, or the like can be used. A camera 53 is also attached to the tip link of the robot arm 51 for capturing images of the work W transported by the work transport device 20 and the tray T transported by the tray transport device 16 to grasp their positions and states. It is The camera 53 is capable of capturing an image with each sampling area A2 as an imaging range, and captures not only a still image but also a plurality of images (moving images) that are continuous in time series at a predetermined frame rate (several tens of fps, etc.). It is possible.

As shown in FIGS. 1 and 2, the work transport device 20 has a plurality of transport lanes 21 capable of transporting the works W from the supply area A1 to the collection area A2 in the front-rear direction (Y-axis direction). A plurality of supply boxes 12 for storing works W to be supplied to each of the plurality of transportation lanes 21 are arranged behind the work transportation device 20 .

The work conveying device 20 includes a conveyor belt 22 and partitions 25 . As shown in FIG. 2, the conveyor belt 22 is stretched over a drive roller 23a and a driven roller 23b. The conveyor belt 22 conveys the work W in the belt feed direction by rotating the drive roller 23a with the drive motor 38 (see FIG. 4), with the work W placed on the upper surface portion 22a (placement portion). Side walls 24 a and 24 b are provided on both sides of the conveyor belt 22 . The drive roller 23a and the driven roller 23b are rotatably supported by side walls 24a and 24b. Further, as shown in FIG. 3, the work conveying device 20 has a support plate 28 that supports the conveyor belt 22 on the back side of the upper surface portion 22a of the conveyor belt 22. As shown in FIG. The support plate 28 is formed with openings 28a at positions corresponding to the collection areas A2 of the plurality of transport lanes 21, respectively. Below each opening 28a, a vertical motion device 30 is arranged for pushing up the upper surface portion 22a from the back surface and moving it vertically. The vertical movement device 30 includes a contact body 31 and a cylinder 32 that vertically moves the contact body 31 so as to pass through the opening 28a. The cylinder 32 is supported by a support base 29 fixed to the side walls 24a, 24b. The partition 25 is a partition plate that extends parallel to the side walls 24a and 24b and partitions the upper surface portion 22a of the conveyor belt 22 into a plurality of transport lanes 21 at regular intervals.

Although not shown, the control device 70 is configured as a well-known computer including a CPU, ROM, HDD, RAM, input/output interface, communication interface, and the like. Various signals from the encoder 45 of the supply robot 40, the encoder 55 of the collection robot 50, the camera 53, the input device 80, and the like are input to the control device 70. FIG. From the control device 70, the drive motor 38 of the workpiece transfer device 20, the vertical movement device 30 (cylinder 32), the drive motor 44 of the supply robot 40, the drive motor 54 of the collection robot 50, the camera 53, the tray transfer device 16, etc. Various control signals are output. Further, the control device 70 outputs a control signal to the vertical motion device 30 to control the operation of the cylinder 32 , whereby the cylinder 32 vertically moves (vibrates) the contact body 31 to perform a loosening operation. FIG. 5 is an explanatory view showing how the bulk work W is unraveled. As shown in the figure, by the unraveling operation, the lumps of the workpieces W in a bulk state are unraveled and separated, so that the workpieces W can be easily picked up by the picking robot 50 . Further, even if the controller stops the operation of the cylinder 32 after the loosening operation is performed, the vibration of the upper surface portion 22a of the conveyor belt 22 does not stop immediately. It takes time for minute vibrations to converge.

In the work system 10 configured in this manner, various controls such as work W supply control, transport control, loosening operation control, pick-and-place control, and the like are sequentially performed. The supply control is performed by driving and controlling the supply robot 40 so as to pick up the necessary work W from the supply box 12 and supply it to the supply area A1 of the corresponding transport lane 21 . Conveyance control is performed by driving and controlling the work conveying device 20 so that the work W supplied to the supply area A1 reaches the collection area A2. The loosening operation control is performed by driving and controlling the cylinder 32 of the vertical movement device 30 corresponding to the sampling area A2 in a state where the work W has reached the sampling area A2. The picking and placing control is performed by driving and controlling the picking robot 50 so as to pick up the works W that have been loosened and separated by the untangling operation control and place them on the tray T in an aligned manner. These controls performed on the works W on each transport lane 21 may be executed in parallel if they do not affect the controls on the works W on the other transport lanes 21 . The details of the collection and placement control will be described below with reference to the flowchart shown in FIG.

6, the control device 70 waits for the loosening operation by the vertical movement device 30 to finish (S100), and when it determines that the loosening operation has finished, the target sampling area is picked up at a predetermined frame rate. The image G of A2 is captured by the camera 53 (S110). Note that FIG. 7 is an explanatory diagram showing how the work W stands still, and the vibration of the work W on the upper surface portion 22a (sampling area A2) converges in the order of FIGS. 7A, 7B, and 7C and comes to rest. show the situation. The control device 70 performs image processing on the image G captured by the camera 53, and changes the images G(i−2), G(i−1), and G(i), which are three consecutive frame images in time series. A quantity is obtained (S120). Note that i indicates the image number based on the imaging order. In S120, the control device 70 extracts, for example, a pixel having a particularly high luminance value among the pixels of the image G as a feature point, and produces three images G(i-2), G(i-1), G(i). is obtained as the amount of change. Alternatively, the control device 70 may obtain the luminance distribution from the luminance value of each pixel of the image G, and obtain the amount of change in the luminance distribution. Since the work W vibrates for a while after the loosening operation is finished (see FIGS. 7A and 7B), the position of the work W in the image G also changes. Such changes appear as movement of feature points in the image G, changes in luminance distribution, etc. Therefore, the controller 70 can determine the degree of displacement of the workpiece W by acquiring the amount of change in S120.

After obtaining the amount of change, the control device 70 determines whether or not the amount of change has converged (S130). If the amount of change obtained in S120 is within a predetermined range, the control device 70 determines that the amount of change has converged. This predetermined range is determined in advance by experiments or the like as a range in which it can be determined that the workpiece W has stopped, and is stored in the HDD or the like of the control device 70 . Further, the control device 70 obtains, for example, the amount of change between the two images G(i-1) and G(i) and the amount of change between the two images G(i-2) and G(i-1), Convergence of the amount of change is determined when all the amounts of change are within a predetermined range. Note that the control device 70 may acquire and determine the amount of mutual change among the images G(i-2), G(i-1), and G(i). When the control device 70 determines in S130 that the amount of change has converged, it determines that the work W has stopped and ends the imaging of the image G (S140). In the present embodiment, the control device 70 detects that the amount of change in the entire area of the image G has converged, such as that the amount of change in each feature point in the image G has converged. It is determined that all of the plurality of works W have stopped (see FIG. 7C).

When the control device 70 determines that the work W is stationary, the control device 70 starts picking up the work W by the picking robot 50. Therefore, the control device 70 picks up each work W from the last captured image G among the plurality of images G used for the determination in S130. A position is detected (S150). By detecting the position of the work W from the last image G in this way, it is possible to quickly start picking up the work W without capturing the image G again after determining that the work W is stationary. The control device 70 executes the process of picking up the works W by the picking robot 50 and placing them on the tray T for all the works W in the target picking area A2 (S160), and executes the picking and placing control routine. finish. In this way, since the picking of the work W by the picking robot 50 is started after it is determined that the work W is stationary, it is possible to prevent picking errors of the work W. FIG. It should be noted that the control device 70 may take an image and check the position of the workpiece W as necessary during the processing of S160.

Here, correspondence relationships between the components of the present embodiment and the components of the present disclosure will be clarified. The conveyer belt 22 (upper surface portion 22a) of the work conveying device 20 of this embodiment corresponds to the supply section, the collection robot 50 corresponds to the robot, the work system 10 corresponds to the work system, and the camera 53 corresponds to the imaging device. and the control device 70 corresponds to the control unit.

In the work system 10 of the present embodiment described above, the picking robot 50 is controlled to pick up the work W after determining that the work W is stationary based on the convergence of the variation amounts of the plurality of images G. FIG. As a result, it is possible to properly pick up the work W by preventing picking errors due to the movement of the work W. In addition, as in the case of setting the waiting time from the end of the loosening operation to the start of picking up the work W, frequent picking errors due to a short waiting time and a decrease in work efficiency due to a long waiting time can be prevented. You can prevent them from inviting you. Therefore, the supplied work W can be collected efficiently and appropriately. Moreover, even if the work W has a shape such as a columnar shape or a conical shape, it is possible to reliably determine that the work W has stopped.

In addition, the last captured image G among the plurality of images G used for determining whether the work W is stationary is used for detecting the position of the work W. FIG. Therefore, when it is determined that the work W is stationary, it is possible to start picking up the work W without taking a new image, so that the work W can be picked up more efficiently. In addition, since it is determined whether the work W is still or not based on the amount of change in the three images G(i-2), G(i-1), and G(i) which are consecutive in time series, it is possible to avoid erroneously determining whether or not the work W is still. can be prevented and the accuracy of determination can be improved.

It goes without saying that the present disclosure is not limited to the above-described embodiments, and can be implemented in various forms as long as they fall within the technical scope of the present disclosure.

For example, in the above-described embodiment, the last captured image G is used to detect the position of the work W. However, the present invention is not limited to this. It can also be used as something to do. However, in order to quickly start picking up the workpiece W, it is preferable to use the image G captured last.

In the above-described embodiment, the conveyor belt 22 conveys the work W as the work conveying device 20, but the present invention is not limited to this, as long as the work W is fed with a predetermined operation. For example, by placing a work W above an inclined portion that slopes downward toward the sampling robot 50 side, the work W runs down the surface (inclined surface) of the inclined portion and is supplied to the sampling robot 50 side. It can also be a thing. In addition, a flat supply unit that can move up and down is provided so as to be connected to the lower end of the inclined portion, or the supply robot 40 is provided so that the workpiece W can be directly supplied, and when the workpiece W is supplied, the supply unit may be moved up and down to untangle the lumps of the work W.

In the above-described embodiment, the convergence of the amount of change is determined from three images G consecutive in time series. , may be determined from the two images G.

In the above-described embodiment, it is determined that all of the plurality of works W are stationary by determining that the amount of change has converged over the entire area of the image G, and then picking up of the works W is started. is not limited to FIG. 8 is a flow chart showing a pick-and-place control routine of a modification. In FIG. 8, the same step numbers are given to the same processes as in FIG. 6, and the description thereof is omitted. In the sampling and placement control routine of the modified example, if the control device 70 determines in S130 that the amount of change has not converged in the entire image, it determines whether the amount of change has partially converged in a partial area of the image G. is determined (S132), and if it is determined that it has not converged, the process returns to S120. In S132, the control device 70 determines that the amount of change has partially converged, for example, based on the amount of change (amount of movement) of the feature point of the area indicating any workpiece W in the image G converging. When it is determined in S132 that the amount of change has partially converged, the control device 70 determines that some of the works W have stopped, and detects the positions of some of the still works W from the image G (S134). , the workpiece W is picked up by the picking robot 50 and placed on the tray T (S136), and the process returns to S120. Here, as shown in FIG. 7, the degree of vibration (movement) of the work W may differ for each work W. For example, the work W(1) in FIG. (See FIG. 7B). Therefore, in S132 to S136, when the vibration quickly converges and a stationary workpiece W is found, the stationary workpiece W is picked up without waiting for all the workpieces W to come to a stationary position. Thus, without waiting for all of the plurality of works W to come to rest, picking can be started from some of the stationary works W, so work W can be picked up more efficiently, and work efficiency can be improved. .

In the above-described embodiment, the camera 53 is attached to the collection robot 50. However, the present invention is not limited to this. Alternatively, the camera may be fixed to a wall such as a ceiling above the work system 10 .

Here, the work system of the present disclosure may be configured as follows. For example, in the work system of the present disclosure, the control device may change the last captured image among the plurality of images used for determining whether the workpiece is stationary to the image captured when the robot picks up the workpiece. It may be used for detecting the position of the workpiece. In this way, when it is determined that the workpiece is stationary, the workpiece can be picked up without taking a new image, so that the workpiece can be picked up more efficiently.

In the work system of the present disclosure, the control device detects that the amount of change has partially converged even before determining that all of the plurality of works are stationary based on the amount of change that has converged over the entire image. The robot may be controlled to pick up the part of the workpieces when it is determined that the part of the workpieces is stationary. By doing this, it is possible to start picking up some of the stationary works without waiting for all of the plurality of works to come to a standstill, so that the works can be picked up more efficiently and the work efficiency can be improved.

In the work system of the present disclosure, the control device acquires the amount of change from three or more images that are consecutive in time series among the images captured by the imaging device, and determines that the workpiece is still. good too. In this way, it is possible to prevent erroneous determination that the workpiece is stationary and improve the determination accuracy, so that the workpiece can be picked more appropriately.

INDUSTRIAL APPLICABILITY The present disclosure is applicable to the work system manufacturing industry and the like.

10 work system, 11 work table, 12 supply box, 16 tray conveying device, 20 work conveying device, 21 conveying lane, 22 conveyor belt, 22a upper surface portion, 23a driving roller, 23b driven roller, 24a, 24b side wall, 25 partition, 28 support plate, 28a opening, 29 support base, 30 vertical movement device, 31 contact body, 32 cylinder, 38 drive motor, 40 supply robot, 41 robot arm, 42 end effector, 44 drive motor, 45 encoder, 50 sampling Robot, 51 robot arm, 52 end effector, 53 camera, 54 drive motor, 55 encoder, 70 control device, 80 input device, T tray, W workpiece.

Claims (3)

A work system in which a robot picks up a plurality of works supplied to a supply unit and performs a predetermined work,
an imaging device that images the plurality of works on the supply unit;
The amount of change between two images captured at a predetermined frame rate by the imaging device is obtained, and the work is picked up after it is determined that the work is stationary based on the convergence of the amount of change. a control device that controls the robot;
with
A work system in which the control device determines that the variation has converged when a plurality of the variations obtained in succession are within a predetermined range. The work system according to claim 1,
The control device uses the last captured image among the plurality of images used to determine that the work is still, to detect the position of the work when the robot picks up the work. Work system . The work system according to claim 1 or 2,
The control device determines whether or not all of the plurality of workpieces are stationary based on the convergence of the variation over the entire image. A work system that controls the robot to pick up the part of the workpiece when it is determined to be stationary.

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