TWI421487B - And a method of detecting the state of the object to be conveyed - Google Patents

Description

Method and device for detecting the state of an object being floated and transported

In the floating transport apparatus that transports the object while floating on the object, the method of detecting the state of the object to be transported by floating is described.

In the manufacture of a semiconductor device or a liquid crystal panel, a glass substrate is used. Usually, the glass substrate is transported while being floated by a fluid such as compressed air in order to prevent injury. However, there are cases in which the glass substrate is in contact with any portion of the floating transport device due to various reasons such as insufficient floating height, and thus the glass substrate is damaged.

In order to confirm the presence or absence of injury, it can be checked by visual inspection. Such work must be interrupted, so highly automated engineering efficiency can be significantly impaired. There must be a method and device for automatically detecting the presence or absence of contact.

Japanese Laid-Open Patent Publication No. 2007-076836 discloses a gas floating transport apparatus that includes a detector that detects a current flowing between the detecting transport body and the transport surface when coming into contact with the transport surface. In such a technique, it is necessary to impart a conductive film to the transfer surface in advance.

In order to automatically detect the presence or absence of contact between the object and the floating transport apparatus, the present invention aims to provide a method and apparatus for detecting the state of the object to be transported by the float.

The first aspect of the present invention is a method of detecting a state in which an object having a plurality of marks is transported from the transport surface to be lifted upward, and is characterized in that the plurality of cameras disposed apart from each other are ingested for floating transport. In the image in the path, each of the images captured by the camera specifies the pixel of the marker in the object, from the position of each of the specified pixels and the position of the camera. The third-order position of the object is calculated.

Preferably, the control device is configured to select one of the groups formed by the presence or absence of contact between the object and the transfer surface and the group of the object to be in contact with the transfer surface based on the third-order position.

Preferably, the control device is configured to calculate the velocity of the object from the temporal change of the third dimensional position.

Preferably, the control device is configured to perform one of the group consisting of detecting the presence or absence of the object and the calculation of the amount of escape of the object based on the temporal change of the third-order position.

Embodiments of the present invention will be described below with reference to the drawings. For convenience of explanation, as shown in FIG. 1, the X, Y, and Z axes, and the directions along the X, Y, and Z directions are defined. This definition is for convenience of explanation, and the present invention is not necessarily limited thereto.

As shown in FIGS. 1 and 6 to 8 , the floating transport apparatus 10 according to the embodiment of the present invention is for moving the object W in the vertical direction (Z direction in the drawing) in the horizontal transport direction (in the figure). X direction) The device to be transported.

In the scope of this specification and the scope of patent application, the term "escape" is defined. Meaning: The object W acts in a direction different from the originally intended direction of transport. For example, when the originally attempted transport direction is the X direction, the trajectory of the object W is correctly aligned with the X direction and is not changed to the Y direction, and it is determined that "the object W has not escaped". On the other hand, even if the trajectory of the object W is approximately coincident with the X direction, when it is changed to the Y direction, it is determined that "the object W is escaping". The object W snake line is of course included in the category of escape.

The object W is an object having a thin overall planar shape, and a thin plate such as a glass substrate for a liquid crystal panel is suitable. The object W is not necessarily all planar, as long as at least a part of the lower surface thereof is planar. In order to float, for example, a fluid such as air can be utilized. The floating transport device 10 can be used in a clean room or the like as needed.

The floating transport device 10 includes a base B extending in the X direction, a transport device 11 arranged in the X direction on the base B, and a plurality of the X and Y directions on the base B. The floating device 37 and the detecting device.

The conveying device 11 has a plurality of rollers 13 arranged in the X direction in the vicinity of the left end and the right end of the base B. Each of the rollers 13 is integrally coupled to a Worm wheel 17 via a rotating shaft 13s, and is rotatably supported by a carriage 33. A pair of drive shafts 19 are provided so as to be able to penetrate the base B in the X direction, and each of the drive shafts 19 is provided with a worm 21 that is operatively engageable with each of the worm wheels 17. An output shaft of the motor 23 is drivably coupled to the front end of each of the drive shafts 19 via a connector or the like. Thereby, each of the rollers 13 receives the driving force of the motor 23 to rotate at the same rotational speed.

As shown in Fig. 7, the upper end portions of the respective rollers 13 are slightly protruded upward from the upper surface of the floating device 37, and are disposed so as to be uniform on a single surface. As shown in Fig. 7, the object W is in contact with the drum 13 that should receive the driving force even in a floating state. Instead of the drum, a conveying means such as a driveable clamp or a belt conveyor may be applied to the conveying device 11.

Referring to Figures 6-8, the floating device 37 is provided with a plurality or a single chamber 25 through which air can flow. The chamber 25 is provided with one or more inlets 27 for allowing air to flow in the lower portion thereof, and a plurality of openings 29 communicating with the floating device 37 at the upper portion thereof. Each of the intake ports 27 is provided with a blower 31 supported by the base B via the carriage 33. The air blowing device 31 is a device for supplying a fluid such as air, and a fan driven by a motor can be used, but is not limited thereto. The air may be supplied by a compressor or by using a pre-stored compressed air, a cylinder of nitrogen or argon, or the like. An opening 35 communicating with the air blowing means 31 may also be provided between the adjacent chambers 25.

Each of the floating devices 37 includes an upper body 39 having a flat upper surface and a leg portion 43 connected to the lower portion thereof. The upper body 39 and the leg portion 43 are both hollow and communicate with each other. The leg portions 43 are fixed to the base B so as to be internally connectable to the opening 29 of the chamber 25. As shown in Fig. 6, the upper body 39 is provided with a discharge hole 41 that communicates with the inside. The plurality of floating devices 37 are height-aligned in such a manner that they are in a single plane with respect to each other. Hereinafter, this plane is referred to as a transfer surface S.

Referring to Figs. 1 and 2, the detecting device is provided with a plurality of cameras 3R, 3L and a control device 5 for processing an image taken by the cameras 3R, 3L. In this example, there are two cameras, but three or more cameras.

The cameras 3R, 3L are respectively mounted to the frame 7, which is configured to span the arranged floating device 37. The camera 3R and the camera 3L are disposed apart from each other so as to have an appropriate interval in the Y direction.

The camera is suitably a digital camera that can be intermittently imaged by a solid-state imaging element such as a CCD. It can also replace a digital camera, and use a camera that can continuously capture images, or an analog camera. Analog cameras can also be combined with analog-to-digital converters. The cameras 3R, 3L are in synchronization with each other, and take in a common area in the path of the floating transport. Further, the cameras 3R, 3L periodically output the taken portraits in the form of digital data.

The area taken by the cameras 3R, 3L is an area shown by a broken line A in Fig. 1, for example. This area A is a path in which the object W is floated and transported in the X direction by the floating transport device 10, and is appropriately set as necessary. Since the camera 3R and the camera 3L are disposed apart from each other in the Y direction, and the common area A in the path of the floating transport is taken, the respective images taken are so-called parallax.

One or more markers 9 attached to the surface of the object W may be provided. When the object W is made of a transparent material like glass, the above-described parallax cannot be clearly detected, but such a mark 9 contributes to clarifying the above-described parallax. Further, in place of the attached label, any object that can be clearly recognized by the logo printed on the object, the wheel of the object, the surface model of the object, the shape, the hologram, or the like can be used.

The control device 5 includes a CPU 5a that performs calculation and processing of data, a RAM 5b that temporarily stores data, and a ROM 5c that continuously stores programs and the like. The control device 5 may further include a memory device such as a hard disk or a solid disk, or a display device such as a display. The CPU 5a is connected to the cameras 3L, 3R and can take in image data output from the camera. The RAM 5b is a data area having data to be taken in by the memory CPU 5a, and a work area for performing various processes. The ROM 5c is a control program that accommodates the execution of the CPU 5a. The CPU 5a analyzes the image data output from the cameras 3L, 3R in accordance with the control program.

The coordinate conversion data read from the memory device or the ROM 5c is accommodated in the data area of the RAM 5b. The coordinate transformation data is a three-dimensional position used as a coordinate value for calculating a specific element in the image. In the data area of the RAM 5b, the data of the coordinate value of the third-order position of the transport surface S to be described later, the shape data of the object W, and the like are accommodated.

In the work area of the RAM 5b, a frame memory area for storing image data output from the cameras 3L, 3R in frame units is secured. The frame memory area can be secured to two cameras 3L and 3R. The image data is alternately written into the two frame memory areas, and the image data is analyzed in the other frame memory area while the image data is being written in one of the frame memory areas.

The CPU 5a performs analysis of image data in accordance with a control program stored in the ROM 5c. 3 to 5 show the flow.

Referring to Fig. 3, when the power is turned on, the control device 5 is activated, and the CPU 5a takes in the image data from the cameras 3L, 3R (step S1), analyzes the captured image data (step S3), and calculates based on the analysis result. The position of the object W (step S5) detects the state of the object (step S7). This series of steps can be repeated.

More specifically, in step S1, the CPU 5a writes the image data output from the cameras 3L, 3R into the two frame memory areas in the RAM 5b. These writes are alternately performed. In the step S3, the CPU 5a analyzes the image data in the other frame memory area while the image data is being written in one of the frame memory areas.

Referring to Figure 4, step S3 is explained in more detail. In step S3, the CPU 5a extracts the logos in the respective portraits picked up by the cameras 3L, 3R (step S31). The extraction of the marker is a well-known method that can be performed by an edge detection method or a pattern recognition method. Next, the CPU 5a determines whether or not the number of the extracted markers is equal to or greater than the number necessary for calculating the third-order position (step S33). When the number is less than the necessary number (NO in step S33), the CPU 5a ends the analysis processing.

When the number of the extracted markers is equal to or greater than the necessary number (YES in step S33), the CPU 5a specifies the positions of the pixels to be identified (step S35), from the respective positions of the specified pixels. The 3-dimensional position of the object is calculated. Since the position of the pixel in each image generated by the parallax is different in the three-dimensional position, the coordinate conversion data is used as the coordinate value. The coordinate value is calculated as the value of an appropriate three-dimensional coordinate system such as an orthogonal coordinate system or a polar coordinate system. The coordinate system can be a global coordinate system or a local coordinate system. When the calculation of the coordinate value is completed, the step S3 of the image data analysis processing is completed.

Referring back to FIG. 3, in step S5, the CPU 5a calculates a group of coordinate values of the lower third-order position of the object W of the region A from the coordinate value of the third-order position of each of the markers calculated in step S35. The lower coordinate value immediately below each mark is obtained by adding the value of the plate thickness of the object W to the coordinate value of each mark. The intermediate point between the marks is estimated by applying an appropriate interpolation method to the group of the coordinate values of the mark, and is secondarily obtained by adding the value of the plate thickness of the object W. Alternatively, the shape data of the object W prepared in advance may be used instead of a certain value of the plate thickness. In this way, the third-order position is calculated for the entire object W.

The details of the step S7 following the step S5 will be described with reference to FIG. 5. The CPU 5a detects the group of coordinate values of the third-order position of the lower surface of the object W calculated in step S5 and the coordinate value of the three-dimensional position of the transport surface S prepared in advance. The presence or absence of contact between the object W and the transfer surface S (step S71). In other words, the lower point of the object W is compared with the group of the coordinate value (height) in the Z direction and the coordinate value (height) of the Z direction of the transport surface S, and it is judged whether it is the same or lower. value. When it is the same or a low value, this point is judged as the point where the object W comes into contact with the conveyance surface. This judgment is repeatedly performed for all points below the object W. When there is no contact at any point, the contact of the object W with the conveying surface S can be detected.

Next, the CPU 5a calculates the speed of the object W from the temporal change of the coordinate value of the third-order position of the object W calculated in step S5 (step S73). That is, the CPU 5a deducts the coordinate value of the previous time point from the coordinate value at a certain time point, thereby calculating the coordinate value of the X direction. The change. The velocity of the object W (in the X direction) is calculated by dividing by the elapsed time.

Similarly, the CPU 5a detects the presence or absence of the escape of the object W from the temporal change of the coordinate value of the third-order position of the object W calculated in step S5 (step S75). That is, the CPU 5a calculates the coordinate value of the Y direction from the coordinate value at a certain point in time to subtract the coordinate value of the previous time point. The value of the calculated change is the escape amount of the object W. When the escape amount of the object W is larger than a threshold value appropriately set in advance, the object W is detected to escape.

By the above completion of step S7, the process of detecting the state of the object W is completed.

According to the above embodiment, the floating transport apparatus 10 including the detecting device operates as follows.

When air is supplied from the air blowing device 31 to the chamber 25, the chamber 25 uniformly distributes air to each of the floating devices 37, and ejects air from each of the ejection holes 41. The ejected air is between the upper surface of the upper body 39 and the lower surface of the object W, and the space surrounded by the opening of the ejection hole 41 generates a uniform pressure to impart buoyancy to the object W, and the transport surface S is upward. Float. On the other hand, by driving the pair of motors 23, the pair of drive shafts 19 rotate in synchronization. By the engagement of the worm wheel 17 and the worm 21, the rotation of the drive shaft 19 is transmitted to the respective rollers 13. The object W is conveyed in the X direction by being brought into contact with the rotating drum 13 in a floating state. The cameras 3L, 3R are the constantly ingested areas A. When the object W passes through the area A, the object W is taken up by the cameras 3L, 3R together with the mark 9. The cameras 3L, 3R output the captured images to the control device 5 in the form of digital data. The control device 5 calculates the third-order position of the object as described above by using the parallax of the image. Then, the control device 5 compares the calculated three-dimensional position with the three-dimensional position of the transport surface S prepared in advance. Further, based on the comparison, the control device 5 detects the presence or absence of contact between the object W and the transport surface S, and/or where the object W contacts the transport surface S.

Further, the control device 5 calculates the velocity of the object W based on the temporal change of the calculated third-order position. The control device 5 further calculates the presence or absence of the escape of the object W and/or the amount of escape of the object W based on the temporal change of the calculated third-order position.

Further, after the step S7 of FIG. 3, the process of controlling the flying height of the object W may be performed. In other words, the control device 5 calculates the distance between the lower surface of the object W in the region A and the transport surface S (that is, the floating height of the object W) from the coordinate value of the calculated third-order position. The control device 5 controls the output of the air blowing device 31 so that the calculated floating height can be matched with the reference height prepared in advance, and can be controlled such that the flying height of the object W can match the reference height.

As can be understood from the above, according to the present embodiment, the third-order position of the object can be detected, and the state of the object such as the speed of the object or the amount of escape or escape of the object can be detected. As described above, the presence or absence of contact between the object and the floating transport device can be detected based on the third-order position of the object, and various controls such as the next can be performed.

According to the calculated speed of the object W, feedback control of the speed of the object W is possible. That is, the control device 5 compares the speed of the object W to be calculated with the reference speed prepared in advance. When the speed of the object W is smaller than the reference speed, the control device 5 controls the speed increasing motor 23, and when the speed of the object W is larger than the reference speed, the control device 5 controls the speed reducing motor 23. The speed of the object W can be controlled in such a manner as to match the reference speed. Alternatively, the output of the air blowing device 31 may be controlled instead of the control of the motor 23. When the floating height is changed by the control of the air blowing device 31, the driving force received by the object W by contact with the drum 13 changes, and as a result, the speed of the object W is controlled.

Moreover, the escape of the object W can be prevented based on the detection of the presence or absence of the object W and the calculation of the amount of escape of the object. That is, as long as a speed difference is generated between the drum 13 in the right row and the drum 13 in the left row, the driving force can be applied to the object W in the direction in which the escape is prevented. Alternatively, by changing the flow rate of the discharge to each of the floating devices 37 by the control of the air blowing device 31, the driving force can be applied to the object W in the direction in which the escape is prevented. That is, the control possibility such as solving the escape is possible.

As described above, the logo 9 is not essential, and any object that can be clearly identified in the captured portrait is available. The extraction of the object in such an image can be easily performed, for example, using a well-known pattern recognition technique. Then, the extracted object can calculate the 3-dimensional position of the object according to the above method.

Further, in the above description, the attached marks 9 are orthogonally arranged at equal intervals in the X direction and the Y direction, respectively. Instead of such an arrangement, it may be an appropriate arrangement such as a hexagonal arrangement or a random arrangement. It is desirable that the density of the mark 9 is uniform, but it is not limited thereto. Further, the marker 9 does not have to be distributed over the entire object W, and is limited to a part thereof.

The present invention will be described with reference to the preferred embodiments, but the invention is not limited to the embodiments described above. The present invention can be implemented by a person skilled in the art in light of the modifications and variations of the embodiments.

[Industry use possibility]

Provided is a method and apparatus for automatically detecting the state of an object to be floated and transported by the presence or absence of contact between the object and the floating transport apparatus.

5. . . Control device

9. . . Identification

10. . . Floating transport device

11. . . Transport device

13. . . roller

13s. . . Rotary axis

17. . . Worm gear

19. . . Drive shaft

twenty one. . . Worm

twenty three. . . motor

25. . . Chamber

27. . . Take the entrance

31. . . Air supply device

33. . . Trailer

35. . . Opening

37. . . Floating device

39. . . Upper body

41. . . Spout hole

43. . . Foot

3R, 3L. . . camera

5a. . . CPU

5b. . . RAM

5c. . . ROM

S. . . Transfer surface

W. . . Object

B. . . Abutment

Fig. 1 is a schematic perspective view of a detecting device according to an embodiment of the present invention.

Fig. 2 is a schematic view showing electrical connection of the detecting device.

Fig. 3 is a flow chart showing a method of detecting the above-described detecting device.

Fig. 4 is a detailed flowchart showing an image data analysis process of the flowchart of Fig. 3;

Fig. 5 is a detailed flowchart showing the floating transport state detection processing of the flowchart of Fig. 3;

Fig. 6 is a partial plan view showing the floating transport apparatus to which the above-described detecting device is applied.

Fig. 7 is a side view of the above-described floating transport device.

Fig. 8 is a partial longitudinal sectional view showing the above-described floating transport device.

7. . . frame

9. . . Identification

37. . . Floating device

3R, 3L. . . camera

A. . . dotted line

W. . . Object

Claims (6)

One method is a method of detecting a state of an object having a plurality of logos that is transported upward from a transport surface, and is characterized in that each of the plurality of cameras disposed apart from each other picks up an area in the path of the floating transport. In each of the images captured by the camera, the position of the pixel of the marker in the object is specified, and the third-order position of the object is calculated from each of the positions of the specified pixel. One of the group selections formed by the presence or absence of contact between the object and the transfer surface and the contact between the object and the transfer surface is detected based on the third dimensional position. The method of claim 1, further comprising: calculating a velocity of the object from a temporal change of the third dimensional position. The method of claim 1, further comprising: performing group selection by detecting the presence or absence of the object and the calculation of the amount of escape of the object based on the temporal change of the third dimensional position One party. An apparatus for detecting a state in which an object having a plurality of marks is transported from above a transport surface, and a plurality of cameras are configured to be separated from each other in order to respectively pick up an area in a path of floating transport And a control device configured to specify the pixel of the aforementioned identifier in the object in each of the images captured by the camera Calculating the third-order position of the object from the position of each of the specified pixels and the position of the camera, and the control device further configured to detect the object and the transport surface based on the third-order position Whether there is contact or any one of the group selections where the object is in contact with the transfer surface. The apparatus of claim 4, wherein the control device further comprises a speed for calculating the object from a temporal change of the third dimensional position. The apparatus according to claim 4, wherein the control device further comprises a group configured to calculate whether or not the object is detected to escape and the amount of escape of the object is calculated based on a temporal change of the third-order position. Either of the parties selected.