WO2014115472A1 - Transferring device and transferring method - Google Patents

Abstract

The purpose of this invention is to allow a transferring device (2), that unloads articles (22) to an unloading location by way of a lifting platform (16) provided in an overhead traveling vehicle (2), to detect, when alignment has failed, which direction a positional deviation for an article has occurred by using a positional deviation sensor (20, 27) and retry unloading. When lowering an article (22) to an unloading location by way of a lifting platform (16), if the part to be engaged (28) of the article is not engaged with the engaging part (7) at the unloading location, the article (22) is lifted and unloaded again on the basis of the positional deviation direction and degree obtained by detecting, with the positional deviation sensors (20, 27), the force that is received by the transferring device (2) from the unloading location side.

Description

Transfer device and transfer method

This invention relates to the unloading of articles by a transfer device.

移 Transfer devices such as overhead traveling vehicles transport items such as FOUPs between load ports, buffers, stockers, etc. on the ground side. Here, a positioning member such as three pins may be provided on the load port side to position the article. When the transfer device unloads an article, the hole or the like at the bottom of the article is positioned by a positioning member and unloaded to a correct position. In order to engage the hole in the bottom of the article with the positioning member, the transfer device needs to store the position of the positioning member.

Patent Document 1 (JP4296914B) discloses that a member equipped with a camera is conveyed by an overhead traveling vehicle and images a mark on a load port side. If the position and posture of the overhead traveling vehicle with respect to the load port are known from the imaging of the mark, transfer data such as the stopping position and posture of the overhead traveling vehicle for unloading are also found. However, since the load port is behind the article, when the article such as FOUP is being conveyed, the load port cannot be imaged. Therefore, the position of the load port is imaged and stored in advance, and unloading is performed according to the storage. Then, since the hole at the bottom of the article does not engage with the positioning member, even if a positioning error occurs, the retry cannot be executed. This is because it is impossible to recognize how much displacement has occurred on which side. In this case, for example, the overhead traveling vehicle is manually controlled to perform unloading. During this time, unloading is delayed, and the traveling route of the overhead traveling vehicle is blocked.

JP4296914B

An object of the present invention is to detect in which direction a position shift occurs when alignment fails at unloading and to allow unloading by retry.

According to the present invention, an article having an engaged portion or an engaging portion at the bottom is fixed to the ground side, and is moved up and down to an unloading position having an engaging portion or an engaged portion and supporting the bottom of the article. A transfer device that unloads by operation,
When the article is lowered to the unloading position, if the engaged part or the engaging part of the article is displaced from the engaging part or the engaged part at the unloading position and does not engage, the transfer device A displacement sensor that detects the direction and degree of displacement by detecting the force received from the unloading position via the article;
And a control unit that controls the transfer device so that the article is lifted again and unloaded again based on the direction and degree of the positional shift obtained by the positional shift sensor. In this specification, the fact that the engagement is not caused by the displacement is simply referred to as displacement.

In addition, the present invention provides an article having an engaged portion or an engaging portion at the bottom, fixed to the ground side, an engaging portion or an engaged portion, and an unloading position that supports the bottom of the article. A transfer method of unloading by lifting and lowering operation,
Lowering the article to an unloading position;
When the engaged part or the engaging part of the article is displaced from the engaging part or the engaged part at the unloading position, by detecting the force that the transfer device receives from the unloading position side via the article, Detecting the direction and degree of misalignment with a misalignment sensor;
The step of controlling the transfer device by the control unit so as to re-raise the article and unload it again based on the direction and degree of the displacement obtained by the displacement sensor is performed in this order. And

When the engaged part or the engaging part of the article is displaced from the engaging part or the engaged part at the unloading position, the transfer device receives a force from the unloading position side. In the following description, the article is described as having the engaged portion and the unloading position side has the engaging portion, but the article may have the engaging portion and the unloading position side may have the engaged portion. If the engaged portion does not engage the engaging portion, the article rides on the engaging portion, and the force applied at this time can be detected by the acceleration sensor. Further, since the article tilts when it rides on the engaging portion, this can be detected by the tilt sensor. When the transfer device moves the elevator up and down to transfer an article, the elevator base is supported by a plurality of suspension materials. When the article rides on the engaging portion, the force applied to the suspension material becomes uneven, and can be detected by a torque sensor or the like. If these sensors are installed so as to determine the direction and degree of displacement, even if unloading fails, the sensor can be recovered by retry. Therefore, it is not necessary to stop the transfer device and unload it manually after waiting for the worker to arrive. In this specification, the description relating to the transfer device also applies to the transfer method as it is.

Preferably, the transfer device includes a traveling carriage that travels along a traveling rail provided in a high space, and a lifting drive unit that lifts and lowers a lifting platform that supports articles by a plurality of suspension members. In the above-described overhead traveling vehicle, the positional deviation sensor is a sensor that detects the inclination of the lifting platform or a sensor that detects acceleration applied to the lifting platform. When the article rides on the engaging portion, the force applied at that time can be detected by the acceleration sensor. In addition, when the article rides on the engaging portion, the elevator base tilts and can be detected by the tilt sensor. In either case, automatic retry can be performed and unloading can be completed. Here, when the overhead traveling vehicle fails to unload, if the automatic traveling cannot be retried, the traveling rail is blocked for a long time, and the subsequent overhead traveling vehicle is prevented from traveling.

Particularly preferably, the overhead traveling vehicle further includes a lateral movement unit that laterally moves the lifting platform with respect to the traveling rail, and a rotation unit that rotates the lifting platform about a vertical axis, and the lifting platform is, for example, an upper limit. And when the article is engaged, or the engagement part is displaced from the engagement part or the engagement part at the unloading position, the control unit moves the lifting platform, for example, The traveling carriage, the lateral movement unit, and the rotation unit are controlled based on the direction and degree of the positional deviation obtained by the positional deviation sensor. If the elevator is raised to the upper limit, even if the position and orientation of the elevator are changed, there is little shaking of the elevator. And since a traveling trolley, a lateral movement part, and a rotation part are controlled, it can be made to succeed in a retry reliably.
Preferably, the control unit controls the traveling carriage, the lateral movement unit, and the rotation unit so as to eliminate the positional deviation obtained by the positional deviation sensor, thereby returning the article to the unloading position again. Let unload.
Particularly preferably, the positional deviation sensor has three kinds of positions including a positional deviation along the traveling direction of the traveling carriage, a positional deviation along the lateral movement direction of the lateral movement unit, and a positional deviation due to rotation around the vertical axis. The controller is configured to detect a deviation, and the control unit controls the traveling carriage so as to eliminate the positional deviation along the traveling direction of the traveling carriage when the article is unloaded again to the unloading position. The lateral movement unit is controlled so as to eliminate the positional deviation along the lateral movement direction of the lateral movement unit, and the rotating unit is controlled so as to eliminate the positional deviation due to the rotation around the vertical axis. Has been.
Most preferably, the misalignment sensors are at least three acceleration sensors that are different in the direction in which acceleration is detected and are attached to a lifting platform.

Side view of main part of transport system using overhead traveling vehicle of embodiment The figure which shows the positioning hole of the bottom of a lift stand, and the position shift of a lift stand Diagram schematically showing displacement of positioning hole with respect to positioning pin Vertical sectional view schematically showing displacement of positioning hole with respect to positioning pin Block diagram of displacement sensor The figure which shows the vertical direction cross section and light-receiving part of a position shift sensor The figure which shows the position of LED light to the light receiving section The figure which shows the position shift sensor which consists of the pressure sensor of the chuck of the lifting platform The figure which shows monitoring the tension of the lifting material of the lifting platform The figure which shows that the acceleration sensor provided in the lifting platform is used as a position shift sensor Diagram showing control system of overhead traveling vehicle The flowchart which shows the algorithm of unloading in an Example

The following is an optimum embodiment for carrying out the present invention. The scope of the present invention should be determined according to the understanding of those skilled in the art based on the description of the scope of the claims, taking into account the description of the specification and well-known techniques in this field. Examples of overhead traveling vehicles will be described below. However, a stacker crane equipped with a slide fork or a SCARA arm, or a transfer fork such as a slide fork with a lifter or a SCARA arm with a lifter, which does not have a traveling carriage, is also used. The embodiment can be applied. In the case of a slide fork or a SCARA arm, unloading is performed by supporting the bottom of the article and lowering the article with a lifter. For example, in the case of a stacker crane, the positional deviation amount in these cases is detected two-dimensionally in the traveling direction and the transfer direction, and in the case of a fixed slide fork, scalar arm, etc., it is detected in one dimension in the transfer direction.

In FIG. 1, 2 is an overhead traveling vehicle, 4 is a traveling rail, and is supported by a column 5 from the ceiling of the building, for example. Reference numeral 6 denotes a load port fixed on the ground side, for example, a place for transferring articles between the processing device and the overhead traveling vehicle 2. The overhead traveling vehicle 2 performs unloading and loading of the article 22 on the load port 6, and in the case of loading, the tolerance for the position and orientation of the lifting platform 16 with respect to the article 22 is high. Hereinafter, although an embodiment will be described regarding unloading to the load port 6, unloading to a buffer or a stocker is the same. Reference numeral 7 denotes, for example, three positioning pins provided on the load port 6, which protrude from the load port 6.

The overhead traveling vehicle 2 includes a traveling carriage 8 and travels along the traveling rail 4. Reference numeral 10 denotes a horizontal movement unit that horizontally moves the rotation unit 12 to the lifting platform 16 in a direction perpendicular to the longitudinal direction of the traveling rail 4 in the horizontal plane. The moving direction may not be perpendicular to the traveling rail 4. The rotating unit 12 rotates the elevating drive unit 14 and the elevating table 16 within a predetermined range such as ± 10 ° to ± 180 ° around the vertical axis. The elevating drive unit 14 suspends the elevating table 16 by, for example, four suspending materials 15 and elevates the elevating table 16 by winding and unwinding the suspending material 15. When the overhead traveling vehicle 2 travels, the lifting platform 16 is raised to the upper limit to prevent the lifting platform 16 from shaking.

The elevator 16 includes a chuck 18 that can be freely opened and closed, supports the flange surface of the bottom of the protrusion 24 of the article 22, and includes a displacement sensor 20 to measure the direction and degree of inclination of the elevator 16. The article 22 is, for example, a FOUP that houses a semiconductor substrate, but may be another article, and includes, for example, three positioning holes 28 provided in a plate-like bottom portion 26. A groove may be provided instead of the positioning hole 28 and the groove and the positioning pin 7 may be engaged. A positioning pin may be provided on the bottom of the article 22 and a positioning hole may be provided on the article placement surface of the load port.

FIG. 2 schematically shows the state of the bottom portion 26 when positioning is successful (solid line) and when positioning fails (dashed line). Causes of positioning failure include positional deviation in the x direction (traveling direction), positional deviation in the y direction (lateral movement direction), and rotation around the vertical axis (rotation angle is θ). Therefore, the displacement sensor 20 measures these values with an appropriate resolution such as ± 3 level or ± 10 level.

FIGS. 3 to 5 show the measurement of misalignment. The positioning pin 7 is provided with a conical surface 7c around the apex 7p, and the lower portion of the positioning pin 7 has a cylindrical shape, for example, arranged in a regular triangle shape on the load port. Has been. In the bottom of the article, positioning holes 28 are provided at three locations so as to fit the positioning pins 7, and a displacement sensor 27 is provided around the positioning holes 28. Note that this article is an article for obtaining transfer data for unloading, and a normal article is not provided with the positional deviation sensor 27. Furthermore, when using the article | item provided with the position shift sensor 27, the position shift sensor 20 provided in the lifting platform of the overhead traveling vehicle is unnecessary.

As shown in FIG. 5, the misalignment sensor 27 includes three semiconductor acceleration sensors 27x, 27y, 27z and a signal processing unit 27c. The semiconductor acceleration sensors 27x, 27y, and 27z include a diaphragm that covers a cavity provided in the silicon substrate, and measures acceleration from the degree of deformation of the diaphragm due to acceleration. By providing three semiconductor acceleration sensors 27x, 27y, and 27z, accelerations in three directions of xyz can be detected. The signal processing unit 27c outputs an integrated value of acceleration for each xyz direction and outputs a mean square of accelerations in three directions with a time resolution such as 10 μsec to 1 msec. Or the signal processing part 27c outputs the acceleration of each direction, without integrating | accumulating.

For example, in FIG. 3, the displacement with respect to the upper right positioning pin is large, and the positional displacement with respect to the upper left and lower center positioning pins is small. In this case, the direction of misalignment can be estimated by comparing the strength of the signals of the three misalignment sensors 27. In addition, a position shift detection signal is first obtained from the positioning hole that has the largest position shift. Furthermore, each displacement sensor 27 outputs a signal in which acceleration is decomposed in three directions of xyz, so that the direction of displacement is known.

FIG. 4 shows a process in which the positioning hole 28 is guided by the positioning pin 7. If the left-right direction in FIG. 4 is the x direction, the positioning sensor 27 detects an impact caused by the contact with the positioning pin 7 as an acceleration in the x direction and the z direction. The positive or negative acceleration in the x direction indicates whether the positioning pin 7 has been displaced to the positive side or the negative side along the x direction.

Therefore, it can be determined how much the article 22 has been displaced in which direction from the magnitude and positive / negative of the signal for each direction of the three positional deviation sensors 27 and the time difference between the signal waveform and the signal waveform for each sensor. . From this data, transfer data for unloading the article to the load port without collision with the positioning pin is obtained. A sensor for obtaining the absolute coordinates of the overhead traveling vehicle, for example, a magnetic linear sensor proposed by the applicant, is provided in the entire traveling route of the overhead traveling vehicle. When the overhead traveling vehicle system is started up, the stop position data for transfer to the load port is obtained from the linear sensor, and the transfer data for unloading is obtained from the position deviation sensor 27. If these data are transplanted (copied) to each overhead traveling vehicle, the article can be automatically transferred without collision with the positioning pin without teaching by the operator.

As described above, the displacement sensor 27 is provided in each of the three positioning holes 28, and by comprehensively analyzing these signals, the displacement in the x, y, and θ directions can be accurately detected. Accurate position correction is possible. 3 to 5, three semiconductor acceleration sensors 27z, 27y, and 27z are provided in one misalignment sensor 27, but the acceleration sensor in the z direction can be omitted. Further, since the direction and degree of the positional deviation can be estimated from the signal strength at the three positional deviation sensors, the time difference between the signals, etc., one acceleration sensor may be provided for each positional deviation sensor.

FIG. 6 shows the misalignment sensor 20, and a pendulum 30 is supported by a cable 34 with an electric wire in a dark room case 29. FIG. The swing of the pendulum 30 is braked by the cable 34. An LED (not shown) is provided in the pendulum 30, and a parallel light beam is taken out from the cross-shaped slit 32. For example, the lid 35 is provided with a slit 36 in a direction rotated by 90 ° with respect to the slit 32. Inside the slit 36, for example, four light receiving elements such as a photodiode array (not shown) are formed in a cross shape along the slit 36. It is arrange | positioned and it detects to which position of the light the slit 36 entered.

FIG. 7 shows the detection principle of the misalignment sensor 20 of FIG. Under normal conditions, the slit 32 is at the position of the solid line in FIG. 7 with respect to the slit 36, and the light is received at one point of the light receiving position 38. For example, when the slit 32 is shifted as indicated by a chain line in the figure, the slit 36 side receives light at, for example, four light receiving positions 39 to 42. The pattern in which the light receiving position shifts is determined by the positional deviation in the x direction, the positional deviation in the y direction, and the rotation angle θ, and these values are known from the pattern of the light receiving position. Further, since the pendulum 30 is braked by the cable 34 and does not shake, the light receiving position is stable.

Other examples of the displacement sensor 20 are shown in FIGS. FIG. 8 shows an example in which a positional deviation sensor is constituted by, for example, four pressure sensors 43. Reference numeral 19 in FIG. 8 denotes a shaft for attaching the chuck 18 to the lifting platform. The load of the article is equally applied to the four pressure sensors 43 when normal. When the article rides on the positioning pin of the load port, the signal from the pressure sensor 43 is not uniform, so that a positional deviation can be detected. Further, the direction (x, y, θ) and the degree of displacement are obtained from the signal pattern of the pressure sensor 43 at that time.

FIG. 9 shows a misalignment sensor that detects misalignment using the tension applied to the suspension material 15. When the article rides on the positioning pin of the load port, the tension applied to the four suspension members 15 becomes uneven, and the direction of displacement (x, y, θ) from the tension distribution between the four suspension members 15 And the degree. However, it is difficult to accurately detect the degree of misalignment with the misalignment sensors of FIGS.

FIG. 10 shows misalignment sensors for detecting misalignment by providing acceleration sensors 44 to 46 on the lift 16. The acceleration sensors 44 to 46 are, for example, semiconductor acceleration sensors, and the acceleration sensor 44 represents acceleration in the x direction. 45 detects the acceleration in the y direction, and the acceleration sensor 46 detects the acceleration in the θ direction. That is, when an article descending at a constant speed rides on the positioning pin, it receives a pulsating force and this force is transmitted to the lifting platform 16, and is detected by the acceleration sensors 44 to 46. The strength of each acceleration component can be determined by the three acceleration sensors 44 to 46, and the direction and extent of the displacement can be determined from these. *

FIG. 11 shows the structure of the overhead traveling vehicle 2, and the control unit 50 controls the traveling carriage 4, the lateral movement unit 10, the turning unit 12, and the lifting drive unit 14. The transfer data storage unit 52 stores transfer data such as a stop position, a lateral movement distance, a rotation angle, and a descending amount for transferring an article to and from the load port. The displacement sensor 20 outputs data indicating how much the displacement is in which direction when the article rides on the positioning pin of the load port. The communication part 54 communicates with the ground side controller 56, receives a conveyance command, and reports a result. Further, when a positional deviation occurs, the communication unit 54 transmits data on the direction and degree of positional deviation to the ground-side controller 56, and the ground-side controller 56 averages this data, for example, and transmits the data to the plurality of overhead traveling vehicles 2. The transfer data in the transfer data storage unit 52 is corrected. When using the position shift sensor 27 instead of the position shift sensor 20, the sensor 27 communicates with the control unit 50 by short-range communication.

Fig. 12 shows the unloading algorithm. In FIG. 12, it is assumed that unloading has failed for some reason during normal operation, not when the overhead traveling vehicle system is started up. When the overhead traveling vehicle stops, the elevator platform is moved laterally, rotated, etc., and then the elevator platform is lowered to perform unloading. At this time, if the transfer data stored in the transfer data storage unit is different from the actual data, or if the accuracy of the traveling of the overhead traveling vehicle, the lateral movement and rotation of the lifting platform is low, the positioning hole of the article becomes a load port The article does not engage with the positioning pin, and the article rides on the positioning pin and fails to unload. Then, the displacement sensor determines the direction and degree of displacement, raises the lifting platform to the upper limit, and prevents the lifting platform from shaking. To correct the misalignment. Next, the elevator platform is lowered again to retry unloading. If the output of the position shift sensor is correct, unloading is successful. If unloading is not successful after multiple retries, the overhead traveling vehicle stops and the operator unloads it manually.

In the embodiment, when the overhead traveling vehicle fails to transfer, the direction and degree of the positional deviation are measured and the retry is performed. For this reason, there is no need to wait for the worker to arrive and recover manually. In addition, when the overhead traveling vehicle system is started up, transfer data for unloading to the load port can be automatically acquired.

2 Overhead Traveling Vehicle 4 Rail 5 Post 6 Load Port 7 Positioning Pin 7c Conical Surface 7p Apex 8 Traveling Cart 10 Lateral Moving Part 12 Rotating Part 14 Lifting Driving Part 15 Lifting Material 16 Lifting Stand 18 Chuck 19 Axis 20 Positional Shift Sensor 22 Article 24 Protrusion 26 Bottom 27 Position displacement sensor 27x, 27y, 27z Semiconductor acceleration sensor 27c Signal processing section 28 Positioning hole 29 Case 30 Pendulum 32 Slit 34 Cable 35 Lid 36 Slit 38 to 42 Light receiving position 43 Pressure sensor 44 to 46 Acceleration sensor 50 Control unit 52 Transfer data storage unit 54 Communication unit 56 Ground side controller

Claims (7)

An article having an engaged part or an engaging part at the bottom is unloaded by lifting and lowering to an unloading position that is fixed on the ground side, has an engaging part or an engaged part, and supports the bottom of the article. A transfer device,
When the article is lowered to the unloading position, if the engaged part or the engaging part of the article is displaced from the engaging part or the engaged part at the unloading position, the transfer device loads the article via the article. A displacement sensor that detects the direction and degree of displacement by detecting the force received from the lowering position;
And a controller that controls the transfer device so that the article is raised again and unloaded again based on the direction and degree of the displacement obtained by the displacement sensor. Mounting device. The transfer device includes a traveling carriage that travels along a traveling rail provided in a high space, and a ceiling traveling device that includes a lifting drive unit that lifts and lowers a lifting platform that supports articles by a plurality of suspension members. by car,
2. The transfer apparatus according to claim 1, wherein the displacement sensor is a sensor that detects an inclination of the lifting platform or a sensor that detects acceleration applied to the lifting platform. The overhead traveling vehicle further includes a lateral movement unit that horizontally moves the lifting platform with respect to the traveling rail, and a rotating unit that rotates the lifting platform about the vertical axis, and travels in a state where the lifting platform is raised. And
When the engaged part or the engaging part of the article is displaced from the engaging part or the engaged part at the unloading position, the control unit re-raises the lifting platform, and then the positional deviation obtained by the positional deviation sensor. The transfer apparatus according to claim 2, wherein the traveling carriage, the lateral movement unit, and the rotation unit are controlled based on a direction and a degree of the movement. The control unit causes the article to be unloaded again to the unloading position by controlling the traveling carriage, the lateral movement unit, and the rotating unit so as to eliminate the positional deviation obtained by the positional deviation sensor. The transfer apparatus according to claim 3, wherein the transfer apparatus is configured as described above. The positional deviation sensor detects three types of positional deviations including a positional deviation along the traveling direction of the traveling carriage, a positional deviation along the lateral movement direction of the lateral movement unit, and a positional deviation caused by rotation around the vertical axis. Configured as
The control unit controls the traveling carriage so as to eliminate the positional deviation along the traveling direction of the traveling carriage when the article is unloaded again to the unloading position, and the lateral movement section moves along the lateral movement direction. The lateral movement unit is controlled so as to eliminate the misalignment, and the rotating unit is controlled so as to eliminate the misalignment due to the rotation around the vertical axis. The transfer device according to claim 4. The transfer device according to claim 5, wherein the displacement sensor is at least three acceleration sensors which are different in the direction in which acceleration is detected and are attached to a lifting platform. An article having an engaged part or an engaging part at the bottom is unloaded by lifting and lowering to an unloading position that is fixed on the ground side, has an engaging part or an engaged part, and supports the bottom of the article. A transfer method,
Lowering the article to an unloading position;
When the engaged part or the engaging part of the article is displaced from the engaging part or the engaged part at the unloading position, by detecting the force that the transfer device receives from the unloading position side via the article, Detecting the direction and degree of misalignment with a misalignment sensor;
The step of controlling the transfer device by the control unit so as to re-raise the article and unload it again based on the direction and degree of the displacement obtained by the displacement sensor is performed in this order. And transfer method.

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