阅读说明：本技术 吊顶输送车 (Suspended ceiling conveying vehicle ) 是由 进武士 中江哲史 于 2019-12-31 设计创作，主要内容包括：本发明涉及一种吊顶输送车。吊顶输送车(10)沿着配置于顶壁的作为输送轨道的轨道(20)而行进并沿着轨道(20)而对作为输送对象的壳体(50)进行输送,其中,当使得对壳体(50)进行保持的升降体(16)在输送用位置(24)与移载用位置(34)之间升降时,对吊顶输送车(10)的动作进行控制的控制器(15)基于相机(40)拍摄的图像而判定由相机(40)进行拍摄的拍摄范围(42)内有无障碍物。(The invention relates to a ceiling conveying vehicle. A ceiling transport vehicle (10) travels along a rail (20) which is a transport rail arranged on a ceiling wall and transports a casing (50) which is a transport object along the rail (20), wherein when a lifting body (16) which holds the casing (50) is lifted and lowered between a transport position (24) and a transfer position (34), a controller (15) which controls the operation of the ceiling transport vehicle (10) judges whether an obstacle is present in an imaging range (42) imaged by a camera (40) based on an image imaged by the camera (40).)

1. A ceiling transport vehicle that travels along a transport rail disposed on a ceiling wall and transports an article to be transported along the transport rail,

the suspended ceiling transport vehicle is characterized in that,

the ceiling transport vehicle is provided with: a traveling carriage that travels along the conveying rail; a main body that moves along the conveying rail together with the traveling carriage; a lifting body which is provided on the main body and can be lifted between a conveying position and a transfer position below the conveying position; an imaging device that images an area below the main body; and a controller for controlling the operation of the ceiling transport vehicle,

the elevator can execute the following actions: an acquiring operation of lowering the article placed on the article placing table below the conveying position to the transfer position and holding the article; and a release operation of lowering the article held at the transport position to the transfer position and disposing the article on the article placement table,

when the elevating body is caused to execute the acquiring operation or the releasing operation, the controller determines whether an obstacle is present in a photographing range photographed by the photographing device based on an image photographed by the photographing device.

2. The ceiling transport cart of claim 1,

when the elevating body is caused to perform the acquiring operation or the releasing operation, the controller searches for a plurality of predetermined markers from an image captured by the imaging device, and sets a monitoring range for determining the presence or absence of an obstacle based on the positions of the plurality of markers.

3. The ceiling transport cart of claim 1,

when the elevating body is caused to perform the acquiring operation or the releasing operation, the controller searches for a shape similar to a predetermined standard shape from an image captured by the imaging device as a marker, and sets a monitoring range for determining the presence or absence of an obstacle based on a position of the marker.

4. Ceiling transport cart according to claim 2 or 3,

setting an image captured by the imaging device at the start of execution of the acquiring action or the releasing action as a reference image, setting an image captured by the imaging device while the acquiring action or the releasing action continues as an in-action image,

the controller determines that an obstacle is present in the imaging range when a difference exceeding a predetermined threshold is generated between the image data in the monitoring range of the reference image and the image data in the monitoring range of the moving image.

5. The ceiling transport vehicle according to any one of claims 1 to 4,

when the elevating body is caused to perform the acquiring action or the releasing action, the controller records an image taken by the photographing device together with a time at which the image is taken.

Technical Field

The present invention relates to a ceiling transport vehicle, and more particularly to a technique of providing a lifting body capable of lifting and lowering an article in a ceiling transport vehicle that transports the article along a transport track.

Background

Conventionally, as one of the transport devices used in semiconductor device manufacturing facilities such as clean rooms, there has been proposed a ceiling-mounted transport vehicle (ceiling-mounted travel transport device) described in japanese patent No. 3371897, which transports the semiconductor device along a transport rail disposed on a ceiling wall of the facility. The ceiling transport vehicle is provided with a trolley with a lifter, and can make a wafer loader of a semiconductor lift between a loading port and a top wall side of a semiconductor manufacturing device.

The ceiling transport vehicle described in patent document 1 is provided with an optical obstacle detection sensor for checking whether or not an obstacle is present in a lifting path of the wafer carrier when the wafer carrier is lifted.

The obstacle detection sensor can irradiate light within a preset detection range, and can investigate the presence or absence of an obstacle within the detection range based on the amount of light reflected by the obstacle detection sensor.

Disclosure of Invention

However, since the optical obstacle detection sensor provided in the ceiling transport vehicle as described in patent document 1 cannot irradiate the entire detection range having a certain degree of width at a time with one light source, it is necessary to repeatedly perform the following operations when detecting an obstacle: after the detection at a certain point is completed, the irradiation angle is switched and the detection is performed at other points.

In order to switch the irradiation angle of the light source, it is necessary to generate mechanical motion by a driving mechanism such as a motor, and therefore, the mechanical loss of the device is caused by friction or the like every time the device is used. Therefore, the conventional obstacle detection sensor has a problem that the life of the mechanism is shortened.

In addition, since a general optical type obstacle detection sensor is fixed at an angle (the angle can be switched only at a constant angle) at which a light projecting pitch (a switching width of an irradiation angle) is constant, there is a problem in that: a small obstacle accommodated in the middle of the light projecting pitch cannot be detected.

Further, since the optical type obstacle detection sensor according to the related art irradiates light from the obstacle detection sensor disposed on the ceiling side toward the load port spaced downward, even if the irradiation angle is slightly varied, the irradiation point is greatly displaced, and light cannot be irradiated to a desired position. Therefore, the following problems still exist in the prior art: the optical axis of the light source must be precisely aligned, and when the optical axis is deviated, an operator needs to climb to the top wall side of the apparatus and perform adjustment work of the optical axis alignment at a high position, which is very labor-consuming. As described above, the ceiling transport vehicle including the conventional optical obstacle detection sensor has a disadvantage of being difficult to operate. In view of the above problems, an object of the present invention is to provide a ceiling transport vehicle including a mechanism for determining the presence or absence of an obstacle, which is relatively easy to handle.

In order to solve the above problem, an example of an embodiment of a ceiling transport vehicle according to the present invention is a ceiling transport vehicle that travels along a transport rail disposed on a ceiling wall and transports an article to be transported along the transport rail, the ceiling transport vehicle including: a traveling carriage that travels along the conveying rail; a main body that moves along the conveying rail together with the traveling carriage; a lifting body which is provided on the main body and can be lifted between a conveying position and a transfer position below the conveying position; an imaging device that images an area below the main body; and a controller that controls an operation of the ceiling transport vehicle, the lifting body being capable of performing the following operations: an acquiring operation of lowering the article placed on the article placing table below the conveying position to the transfer position and holding the article; and a release operation of lowering the article held at the transport position to the transfer position and disposing the article on the article mounting table, wherein when the lifting body is caused to perform the acquisition operation or the release operation, the controller determines whether or not an obstacle is present in an imaging range imaged by the imaging device based on an image imaged by the imaging device.

Further, it is preferable that the controller searches for a plurality of markers predetermined in advance from an image captured by the imaging device when the ascending/descending body is caused to perform the acquiring operation or the releasing operation, and sets a monitoring range for determining the presence or absence of an obstacle based on positions of the plurality of markers.

Further, it is preferable that the controller searches for a shape similar to a predetermined standard shape from an image captured by the imaging device as a marker when the elevating body is caused to perform the acquiring operation or the releasing operation, and sets a monitoring range for determining the presence or absence of an obstacle based on a position of the marker.

Preferably, the controller determines that an obstacle is present in the imaging range when a difference exceeding a predetermined threshold value is generated between image data in the monitoring range of the reference image and image data in the monitoring range of the in-motion image.

Further, it is preferable that the controller records an image captured by the image capturing device together with a timing of capturing the image when the elevating body is caused to perform the capturing action or the releasing action.

According to the ceiling transport vehicle of the embodiment of the present invention, since the presence or absence of an obstacle is determined based on the image captured by the imaging device, a drive mechanism for switching the irradiation angle of the light source, such as a conventional optical obstacle detection sensor, is not required, and the life of the mechanism for performing obstacle determination is extended.

Further, since all objects included in the imaging range are reflected in the image captured by the imaging device, it is possible to detect even a small obstacle that cannot be detected by the conventional optical obstacle detection sensor.

Further, since the direction of the imaging device does not need to be set as precisely as long as the transfer position and its surroundings are included in a certain area within the captured image, the work that has been conventionally performed and that is time-consuming and labor-consuming, such as the worker climbing up to a high place and manually adjusting the direction of the light source, is not necessary.

Drawings

Fig. 1 is a side view showing a ceiling transport vehicle and an article mounting table according to an embodiment of the present invention.

Fig. 2 is a plan view showing the top surface of the article placing table and the positioning pins provided on the article placing table.

Fig. 3 is a plan view showing the shape of the housing including the top flange.

Fig. 4 is a flowchart showing the steps of the obstacle detection processing.

Description of reference numerals

10: a ceiling transport vehicle; 16: a lifting body; 32: an article-placing table; 36: positioning pins; 40: a camera; 42: a shooting range; 48: monitoring the range; 50: a housing; 52: a top flange.

Detailed Description

Fig. 1 shows an example of an embodiment of a ceiling transport vehicle according to the present invention. In facilities (semiconductor manufacturing facilities, etc.) using the ceiling transport vehicle 10, a rail 20 as a transport rail is disposed on the ceiling wall side, and the traveling carriage 12 on the ceiling transport vehicle 10 travels along the rail 20. The traveling carriage 12 is coupled to a main body portion 14 of the ceiling transport vehicle 10, and a lifting body 16 is provided on the main body portion 14. The lifting body 16 is provided with a lifting mechanism 18, so that the lifting body 16 can be lifted between the ceiling wall side and the floor surface side of the facility.

An article table 32 is provided on the floor surface side of the apparatus. The article stage 32 is a stage on which a case 50 (a Front-opening unified pod (so-called FOUP) as a wafer carrier for a semiconductor) as an article to be transported in the apparatus can be stably placed, and functions as the article stage 32, for example, a load port of a semiconductor manufacturing apparatus.

The lifting body 16 can hold the case 50 by the arm 19, the chuck, and the like, and can lift and lower the case 50 between the conveyance position 24 in the main body 14 (top wall side) and the transfer position 34 above the article table 32 (floor surface side). Specifically, the lifting body 16 is capable of performing an acquiring action and a releasing action. In the acquiring operation, the vertically movable body 16, which is not holding the case 50, is lowered from the conveying position 24 to the transfer position 34, and the arm 19 of the vertically movable body 16 grips the top flange 52 of the upper portion of the case 50 disposed at the transfer position 34 on the article table 32, thereby holding the case 50 by the vertically movable body 16.

In the release operation, the vertically movable body 16 holding the casing 50 is lowered from the conveying position 24 to the transfer position 34 above the article mounting table 32, and the casing 50 is placed on the article mounting table 32 by releasing the holding of the casing 50 by the vertically movable body 16.

In the ceiling transport vehicle 10 of the present embodiment, a camera 40 as an imaging device is provided below the main body 14 and at a position deviated from the lifting path of the lifting body 16. The camera 40 shoots an area downward and below the main body 14. The imaging range 42 in which the image captured by the camera 40 is taken is expanded as it goes downward, and a wide range including a range in which the housing 50 is disposed is taken as the imaging range 42 at the height position of the article mounting table 32 as shown in fig. 1. The imaging range 42 may extend not only to the article mounting table 32 but also to the periphery of the article mounting table 32 (an area outside the article mounting table 32).

The ceiling transport vehicle 10 is provided with a controller 15 (processor or the like) that controls the operation of the ceiling transport vehicle 10. The controller 15 executes control for the traveling operation of the traveling carriage 12, the acquisition operation and release operation of the vertically movable body 16, image processing of the image captured by the camera 40, and the like. In fig. 1, the controller 15 is shown as being incorporated in the main body 14, but a computer or the like that controls the operation of the ceiling transport vehicle 10 by communication, which is a device separate from the ceiling transport vehicle 10, may also function as the controller 15.

The controller 15 can switch between a conveyance operation of traveling along the rail 20 and an acquisition operation or a release operation of stopping traveling and raising and lowering the lifting body 16, depending on the current position of the ceiling transport vehicle 10. For example, in a semiconductor device, what kind of housing 50 should be arranged on which article mounting table 32 (load port) or what ceiling transport vehicle 10 should transport the housing 50 arranged on which article mounting table 32 may be designated by a host device operated by a manager of the device. In this case, the controller 15 receives the above-described specification information from the host device, and stops the travel of the traveling carriage 12 and starts the pick-up operation or the release operation when the casing 50 (being conveyed) currently held by the ceiling transport vehicle 10 reaches the position above the article placing table 32 to be placed, or when the ceiling transport vehicle 10 reaches the position above the article placing table 32 to which the casing 50 to be conveyed by the ceiling transport vehicle 10 is placed. Here, before the vertically movable body 16 is moved up and down to perform the capturing operation or the releasing operation, the controller 15 captures a reference image indicating a situation below the main body 14 at the start of the operation by the camera 40.

For example, when the release operation is started, the casing 50 is not placed on the article table 32 below the ceiling-suspended carrier vehicle 10, and the top surface of the article table 32 is exposed. The condition of the top surface of the article table 32 is shown in the top view of fig. 2.

On the top surface of the article mounting table 32, a positioning pin 36 as a marker is provided as a mark where a target position 55 of the housing 50 should be arranged. The positioning pins 36 are arranged and shaped according to standards in the case of a load port of a semiconductor manufacturing apparatus. For example, pins which are upwardly convex and circular in plan view are buried and arranged on the top surface in a set of 3 pins, each pin forming the apex of a regular triangle, the set corresponding to one target position 55. For the article stage 32 of fig. 2, the 2-position target position 55 is prepared.

Next, a case where the release operation is performed at the target position 55 on the left side in fig. 2 will be described. First, a reference image of the imaging range 42 including the target position 55 is imaged by the camera 40. The controller 15 performs image processing on the reference image and searches for a plurality of (here, 3) positioning pins 36 included in the image. For example, if the article mounting table 32 is made of metal and the top surface appears silver due to metallic luster, and the positioning pins 36 are colored in black, the controller 15 searches for a portion where a black dot exists in a silver background. In addition, if the positioning pin 36 is color-discriminated such that the top portion is white and the bottom end portion is black, the controller 15 searches for a double circle of white and black.

The search of the positioning pin 36 may be performed for the entire imaging range 42, but it may be predetermined in which range in the image the search is performed in order to shorten the search time. For example, the search for the locating pin 36 may be performed in 3 search ranges 46 of an oval shape as shown in fig. 2. As the setting of the search range 46, for example, a range that can be defined regardless of the image can be set, such as "an ellipse of a predetermined shape having a center at a point shifted by X pixels from the left end of the image to the right side and by Y pixels from the lower end of the image to the upper side".

When a predetermined number (here, 3) of positioning pins 36 are found, the controller 15 determines the monitoring range 48 to be a monitoring target of whether or not an obstacle is present based on the positions of these positioning pins 36. For example, the controller 15 calculates the center coordinates 39 of the virtual circle 38 passed through the 3 positioning pins 36, and sets a range spaced apart from the center coordinates 39 by a predetermined distance as the monitoring target 48.

Here, the controller 15 can also calculate the orientation of the horizontal axis 38X and the vertical axis 38Y of the virtual circle 38 from the positions of the 3 positioning pins 36. The orientation of the horizontal axis 38X and the vertical axis 38Y of the virtual circle 38 corresponds to the desired orientation of the casing 50 when the casing 50 is disposed at the target position 55. In fig. 2, the case where the orientation of the camera 40 is deviated to cause the orientation of the photographing range 42 to be inclined with respect to the orientations of the horizontal axis 38X and the vertical axis 38Y of the virtual circle 38 is shown, but even if the photographing range 42 is so inclined, the controller 15 can calculate the horizontal axis 38X and the vertical axis 38Y of the desired orientation based on the positions of the 3 positioning pins 36.

As described above, when the monitoring target 48 is set to the range spaced apart from the center coordinate 39 by the predetermined distance, it is preferable to set the monitoring range 48 by taking into consideration the possibility of the inclination of the imaging range 42, not by the distance in the direction along the horizontal and vertical frames of the image but by the distance in the direction parallel to the horizontal axis 38X and the vertical axis 38Y of the virtual circle 38 calculated, in fig. 2, the monitoring range 48 is configured by the range of the distance L X to the left and right sides in the direction of the horizontal axis 38X with respect to the center coordinate 39 of the virtual circle 38, and the rectangular range of the position spaced apart by the distance L Y1 to the position spaced apart by the distance L Y2 in the direction of the vertical axis 38Y with respect to the center coordinate 39, and as shown in fig. 2, the monitoring range 48 is set to the outer side than the target position 55.

On the other hand, when the pickup operation is started, the top surface of the casing 50 is photographed by the camera 40 because the casing 50 is placed on the article placement table 32 below the ceiling transport vehicle 10. The shape and size of the housing 50 are predetermined according to standards when the front surface of the housing is, for example, a Front Opening Unified Pod (FOUP) which is a wafer carrier of a semiconductor. In particular, the contour of the arm 19 of the vertically movable body 16 and the top flange 52 held by the chuck is defined as a standard shape.

Therefore, when the capturing operation is performed, a shape similar to the standard shape of the top flange 52 is searched for from the captured reference image and used as the marker. Fig. 3 is a plan view showing an example of a specific top surface shape of the housing 50, particularly an outline shape of the top flange 52.

Since the contour shape includes a plurality of notches having a characteristic shape, the position of the top flange 52 can be determined substantially reliably if the contour shape is similar to the overall shape. However, in a case where the article mounting table 32 and the case 50 are both silver and there is little color difference, or in a case where the top flange 52 is not sufficiently irradiated due to the irradiation manner of the apparatus illumination, it is difficult to accurately search for the entire shape. Therefore, the following method is adopted here: the controller 15 searches the shape at multiple locations and finds several of them, thereby being able to determine the position of the top flange 52.

Specifically, the controller 15 searches for the shape of the four corners 54 of the top flange 52 shown in fig. 3. Since the four corners 54 have characteristic shapes, if a shape similar to these is found, it can be determined that the position of the top flange 52 is found. Further, the controller 15 may search for a notch shape or the like provided on each side of the top flange 52 in addition to the four corners 54.

For example, if the top flange 52 is found at the upper right and lower left or upper left and lower right of the four corners 54, that is, 2 parts on the diagonal line, it can be determined that the position of the top flange 52 is found, since the contour shape of the top flange 52 is defined by the standard, it is possible to specify the position by finding a part of the top flange 52, and calculate the position of the other part of the top flange 52, as described above, the controller 15 calculates the position of the center point 59 of the top flange 52 based on the found position of the four corners 54, and then sets the range spaced a predetermined distance from the center point 59 as the monitoring target 48, and in fig. 3, the range spaced a distance L X to the left and right of the center point 59, and the range of a rectangle spaced a distance L Y1 from the center point 59 to a L Y2 constitutes the monitoring range 48, and as shown in fig. 3, the monitoring range 48 is set to be located outside the casing 50.

As described above, when the acquisition operation or the release operation is started, the process of capturing the reference image (step S1 in fig. 4), the process of searching for the marker in the reference image or the marker of the marker section (step S2), and the process of setting the monitoring range 48 (step S3) are executed. When the monitoring range 48 is set, the elevating mechanism 18 starts the operation of elevating the elevating body 16 (step S4).

When the up-down operation is started, the controller 15 captures an in-operation image indicating the state of the top surface of the article mounting table 32 being moved up and down by the camera 40 (step S5). Then, it is determined whether or not there is no difference in the portion reflected in the monitoring range 48 between the in-operation image and the reference image (step S6).

To describe in detail step S6, since the monitoring range 48 is set to be outside the target position 55 or the casing 50 as described above, only the top surface of the article table 32 is reflected during the acquisition operation or the release operation within the monitoring range 48, and the above-described reason is that the top surface is always fixed (the state of the top surface with respect to the reference image is not changed). When the image in the monitoring range 48 changes during the execution of the operation, it means that an obstacle (a hand of the operator, etc.) enters the monitoring range 48. Therefore, in step S6, it is determined whether or not there is no difference between the in-motion image and the reference image in the monitoring range 48. Even if there is no obstacle, the color may be slightly changed due to slight vibration of the device, fluctuation of lighting conditions, or the like, and therefore a slight difference is allowed. When the difference exceeds a predetermined threshold (e.g., 40 pixels) (step S6 — yes), it is determined that an obstacle is present.

When determining that there is an obstacle, the controller 15 transmits an obstacle detection signal to the ascending/descending body 16 and the upper-level device (step S7). When an obstacle actually exists, how to perform the handling varies depending on the apparatus, and for example, it is conceivable to stop the operation until the obstacle is removed, or to record that the "obstacle is detected" and continue the operation as it is.

After the obstacle detection signal is transmitted or when the difference exceeding the threshold is not found by the comparison between the in-motion image and the reference image (no at step S6), the controller 15 determines whether the acquisition motion or the release motion is completed (step S8). The determination can be made by, for example, checking whether the lifting body 16 is returned into the main body portion 14 and the housing 50 is held by a method such as measuring the weight of the lifting body 16 by a weight scale provided in the ceiling transport vehicle 10.

When the acquisition operation or the release operation is completed (yes in step S8), the controller 15 resumes driving of the stopped traveling carriage 12 and transitions to the conveyance operation for traveling along the track. If the acquiring operation or the releasing operation has not been completed (no in step S8), the above-described operations are repeatedly executed from the step of capturing the image in motion (return to step S5). As described above, the ceiling transport vehicle 10 of the present embodiment can execute the pick-up operation or the release operation while determining the presence or absence of an obstacle.

In steps S1 to S8 described above, the presence or absence of an obstacle is determined only by comparing the reference image with the in-motion image, but a history of the determination may be stored as a record. For example, an image memory for recording the obtained image data is provided in the ceiling transport vehicle 10. It is preferable that the ceiling transport vehicle 10 be provided with a clock device for measuring the current time and a timer for measuring the time elapsed since the start of operation on the day.

For example, at the time of capturing the reference image in step S1 or at the time of capturing the image during the operation in step S5, the data of the captured image is recorded in the image memory together with the time at which the image was captured. That is, the image capturing time is recorded. In this way, the shooting time is recorded, and when an obstacle occurs, the image data recorded by the manager of the device is compared with the shooting time, so that it is possible to know at which stage of the action the obstacle occurs. In addition, since the image is recorded, the manager of the apparatus can investigate what the obstacle is after that. As a specific example, whether the operator blocks the camera 40 or the operator has erroneously detected the camera can be examined as an image. The camera 40 is an imaging device for investigating the presence or absence of an obstacle during operation, that is, a device for ensuring safety, but a device for ensuring safety may be used as a device for recording the history of a work as described above.

According to the ceiling transport vehicle 10 of the above embodiment, since all objects reflected in the imaging range 42 imaged by the camera 40 can be detected, it is possible to detect even a small obstacle accommodated in the middle of the light projection pitch (constant angle) that cannot be detected by the conventional optical obstacle detection sensor.

Further, although the conventional optical obstacle detection sensor requires a drive mechanism that generates mechanical loss to adjust the irradiation angle, the life of the sensor is shortened, but the drive unit is not required for the imaging device such as the camera 40, and the life of the device is prolonged.

In the above embodiment, the search range 46 and the monitoring range 48 shown in fig. 2 are automatically set, but the controller 15 may transmit the captured image to an external device such as an adjustment console, and the operator may manually set the captured image while checking the captured image using the adjustment console. In this case, since the adjustment of the device for obstacle determination is completed only by the operator changing the setting while viewing the image, it is not necessary to perform a time-consuming and labor-consuming operation such as manually adjusting the irradiation angle of the light source by the operator climbing to a high place with respect to the conventional optical obstacle detection sensor.

In the above embodiment, the monitoring range 48 is set using the positioning pins 36 as a plurality of markers when the case 50 is not present on the article placement table 32 in the release operation, but the monitoring range 48 can be determined using a plurality of predetermined arrangement marks provided on the top surface of the case 50 as a plurality of markers when the acquisition operation is performed, that is, when the case 50 is not placed on the article placement table 32.

In the above embodiment, the monitor range 48 is set using the standard shape of the top flange 52 of the case 50 as the indicator when the case 50 is placed on the article placing table 32 in the pickup operation, but when the case is released, that is, when the case 50 is not present on the article placing table 32, the monitor range 48 can be determined using the shape of the indicator as the indicator by providing the indicator having a predetermined shape on the top surface of the article placing table 32.

In the above embodiment, the presence or absence of an obstacle is determined by examining the state of the monitoring range 48 in the imaging range 42, but the presence or absence of an obstacle can be determined for the entire imaging range 42 (the article placement platform 32 and its surroundings) by using an AI, an image analysis program, or the like, which can distinguish an obstacle from the casing 50 (and an obstacle that is not likely to be reflected in normal operation) by analyzing the contour shape in the image, or the like.