Aerial transport vehicle

Abstract

An overhead transport vehicle is provided with: a holding unit that is provided so as to be liftable with respect to a main body and holds an article; a lifting drive unit that lifts and lowers the holding unit; and a recognition device that recognizes the position of the holding unit in the horizontal direction and the position of the holding unit in the height direction.

Description

Technical Field

[0001] The present disclosure relates to an aerial transport vehicle. Background Art

[0002] Patent Document 1 describes a technology related to an aerial transport vehicle. The vehicle comprises a lifting platform (holding unit) configured to be raised and lowered relative to a main body and having a clamp, and a lifting drive unit that raises and lowers the lifting platform. In the vehicle described in Patent Document 1, the lifting drive unit is equipped with a vibration detection sensor. This vibration detection sensor emits a laser beam toward a reflector on the upper surface of the lifting platform and detects vibration of the lifting platform based on whether or not the reflected light (returning light) is detected.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2020 / 121765 Summary of the Invention

[0006] In an aerial transport vehicle, when raising or lowering a holding unit, there may be a situation where an obstacle exists at a specific height. Therefore, it is desirable to accurately determine the amount of sway in the holding unit and the height at which the holding unit is located. In this regard, the aforementioned aerial transport vehicle only detects whether the amount of sway in the holding unit is within a specified range (with regressive light) or above the specified range (without regressive light). Therefore, there is a concern that the amount of sway in the holding unit and the height at which the holding unit is located cannot be accurately determined.

[0007] Therefore, an object of the present disclosure is to provide an overhead transfer vehicle that can accurately grasp the amount of shaking of a holding unit and accurately grasp the height at which the holding unit is located.

[0008] (1) The aerial transport vehicle disclosed in the present invention comprises: a holding unit that is configured to be able to be raised and lowered relative to a main body and to hold articles; a lifting drive unit that raises and lowers the holding unit; and an identification device that identifies the position of the holding unit in the horizontal direction and in the height direction.

[0009] In this aerial transport vehicle, when the holding unit is raised or lowered, the recognition device can determine the holding unit's height position and quantify its sway based on the recognition results. This allows accurate determination of both the amount of sway and the height of the holding unit.

[0010] (2) In the overhead transport vehicle described in (1) above, a reflective component may be provided on the holding unit, and the identification device may include: a sensor that irradiates light toward the reflective component at multiple irradiation angles within a monitoring range including the reflective component and detects multiple regressive lights reflected by the reflective component in response to the irradiation; and a processing unit that calculates the horizontal position and the height position of the holding unit based on the detection results of the multiple regressive lights detected by the sensor. In this case, the horizontal position and the height position of the holding unit can be easily detected using the regressive light.

[0011] (3) In the aerial transport vehicle described in (2) above, when the traveling direction of the aerial transport vehicle is defined as the X direction and the horizontal direction perpendicular to the X direction is defined as the Y direction, the sensor may irradiate light toward the reflective member in a manner of scanning in the Y direction within the monitoring range, the processing unit may calculate an angle average and a distance average with respect to the optical axis of a plurality of detected regressive lights, and calculate the position of the holding unit in the Y direction based on the angle average and the distance average. In this case, the amount of shaking of the holding unit in the Y direction can be accurately determined.

[0012] (4) In the overhead transport vehicle described in (3) above, the shape of the reflective member may include a shape whose width in the Y direction varies as it approaches the X direction, and the processing unit may determine the position of the holding unit in the X direction based on the number of previously stored regressive lights and the number of the plurality of detected regressive lights. In this case, the amount of X-direction swing of the holding unit can be accurately determined, and the height of the holding unit can be accurately determined.

[0013] (5) The overhead transfer vehicle described in any one of (1) to (4) above may further include a determination unit that determines whether the horizontal position of the holding unit identified by the identification device is within an allowable range. In this case, it is possible to determine whether the amount of shaking of the holding unit is allowable.

[0014] (6) The aerial transport vehicle described in any one of (1) to (5) above may also include a lateral transfer mechanism that moves the lifting drive unit laterally relative to the main body. Thus, when lifting or lowering the vehicle to transfer articles between the vehicle and a loading unit located laterally of the main body, the amount of shaking of the holding unit and the height of the holding unit can be accurately determined.

[0015] (7) In the overhead transport vehicle described in (6) above, when the lifting drive unit is moved sideways by the lateral transfer mechanism, the recognition device may correct the horizontal position of the holding unit based on a pre-stored correction value corresponding to the inclination of the lifting drive unit. Thus, even if the illumination direction of the sensor is tilted due to the inclination of the lifting drive unit when the lifting drive unit is moved sideways by the lateral transfer mechanism, the amount of shaking of the holding unit and the height of the holding unit can be accurately determined.

[0016] (8) The overhead transfer vehicle described in any one of (1) to (7) above may also include a storage unit that stores the horizontal position and the height position of the holding unit identified by the identification device in a time sequence for a predetermined period. In this case, the movement of the holding unit can be grasped, and the grasped movement of the holding unit can be used, for example, for maintenance.

[0017] Effects of the Invention

[0018] According to the present disclosure, it is possible to accurately grasp the shaking amount of the holding unit and accurately grasp the height at which the holding unit is located. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a side view showing an overhead transfer vehicle according to one embodiment.

[0020] Figure 2 This is a front view showing the sensor and reflector in their initial state.

[0021] Figure 3 middle, Figure 3 (a) means Figure 2 Schematic top view of the reflector. Figure 3 (b) means Figure 2 A schematic three-dimensional diagram of the sensor and reflector.

[0022] Figure 4 This is a block diagram showing a transport vehicle controller.

[0023] Figure 5 This is a front view showing the sensor and reflector during transfer.

[0024] Figure 6 middle, Figure 6 (a) means Figure 5 Schematic top view of the reflector. Figure 6 (b) means Figure 5 A schematic three-dimensional diagram of the sensor and reflector. DETAILED DESCRIPTION

[0025] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or corresponding elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0026] like Figure 1 As shown, the aerial transfer vehicle 1 of the embodiment travels along a track 20 laid near the ceiling of a clean room for manufacturing semiconductor devices. The track 20 forms a travel path for the aerial transfer vehicle 1. The aerial transfer vehicle 1 is a transport vehicle that can transport an article 200 and transfer the article 200 relative to a loading port 300. The article 200 is, for example, a FOUP (Front Opening Unified Pod) that accommodates a plurality of semiconductor wafers. The loading port 300 is, for example, a loading portion provided on a processing device that performs various processes on semiconductor wafers. There is no particular limitation as to the article 200 and the loading port 300. In the example here, the loading port 300 is located at a position away from the track 20 in the horizontal direction (to the side of the travel direction of the aerial transfer vehicle 1).

[0027] In the following description, the terms "up" and "down" correspond to the vertically upper and lower directions, respectively. The term "front" corresponds to the front side of the AMT 1 in the direction of travel, and the term "rear" corresponds to the rear side of the AMT 1 in the direction of travel. The X direction corresponds to the travel direction, the Z direction corresponds to the vertical direction, and the Y direction corresponds to the lateral direction (the horizontal direction perpendicular to the travel direction).

[0028] The overhead transport vehicle 1 includes a frame unit 2, a travel unit 3, a traverse unit 4, a theta unit 5, a lift drive unit 6, a holding unit 7, and a transport vehicle controller 8. The frame unit 2 includes a center frame 15, a front frame 16, and a rear frame 17. The frame unit 2 constitutes the main body. The front frame 16 extends downward from the front end of the center frame 15. The rear frame 17 extends downward from the rear end of the center frame 15.

[0029] The travel unit 3 is arranged on the upper side of the central frame 15. The travel unit 3 travels along the track 20 by receiving power supply in a non-contact manner from a high-frequency current line laid along the track 20. The transverse unit 4 is arranged on the lower side of the central frame 15. The transverse unit 4 moves the θ unit 5, the lifting drive unit 6, and the holding unit 7 in the Y direction (lateral direction) relative to the frame unit 2. The transverse unit 4 slides the θ unit 5, the lifting drive unit 6, and the holding unit 7 in the Y direction relative to the frame unit 2 using the driving force of a driving mechanism (such as a driving motor, pulleys, and belts) not shown in the figure. The transverse unit 4 constitutes a transverse transfer mechanism. The θ unit 5 is arranged on the lower side of the transverse unit 4. The θ unit 5 rotates the lifting drive unit 6 and the holding unit 7 in a horizontal plane.

[0030] The lifting drive unit 6 is disposed below the θ unit 5. The lifting drive unit 6 raises and lowers the holding unit 7 in the Z direction by unwinding and reeling in a plurality of suspension members B, such as belts, connected to the holding unit 7. The suspension members B are flexible. The lifting drive unit 6 constitutes a lifting drive unit. The holding unit 7 is disposed below the lifting drive unit 6. The holding unit 7 is configured to be able to be raised and lowered relative to the frame unit 2 by the lifting drive unit 6. The holding unit 7 includes a holding member 12, such as a pair of clamps, that can be opened and closed in the horizontal direction. The holding unit 7 holds the flange 201 of the article 200 using the pair of holding members 12.

[0031] The transport vehicle controller 8 is configured on the central frame 15. The transport vehicle controller 8 is an electronic control unit composed of a CPU (Central Processing Unit), a ROM (Read only memory) and a RAM (Random access memory). The transport vehicle controller 8 is a control unit that controls each part of the aerial transport vehicle 1. The transport vehicle controller 8 can also be composed of multiple electronic control units. In the case of being composed of multiple electronic control units, these electronic control units can also be connected via a communication network such as the Internet or an intranet to logically construct a unit. The transport vehicle controller 8 can also be configured on the front frame 16, etc.

[0032] The aerial transport vehicle 1 constructed as described above operates, for example, as follows when transferring articles 200 from the loading port 300 in a lateral direction. At the stop position corresponding to the loading port 300, the aerial transport vehicle 1 drives the lateral unit 4 to move the holding unit 7 in the entry direction relative to the frame unit 2. At the same time, the orientation of the holding unit 7 is adjusted by driving the θ unit 5 as needed. The entry direction refers to the direction in which the holding unit 7 in the lateral direction enters in a manner protruding from the frame unit 2. Next, the aerial transport vehicle 1 drives the lifting drive unit 6 to lower the holding unit 7, and uses the holding unit 7 to hold the flange 201 of the article 200 on the loading port 300. The aerial transport vehicle 1 drives the lifting drive unit 6 to raise the holding unit 7 to the raised end. Furthermore, the aerial transport vehicle 1 drives the lateral unit 4 to move the holding unit 7 in the exit direction, which is the opposite direction of the entry direction, so that the holding unit 7 is located between the front frame 16 and the rear frame 17.

[0033] On the other hand, when the aerial transport vehicle 1 transfers the article 200 laterally to the loading port 300, it operates, for example, as follows. At a stop position corresponding to the loading port in the lateral direction, the aerial transport vehicle 1 drives the lateral unit 4 to move the holding unit 7 holding the article 200 in the entry direction relative to the frame unit 2. At the same time, the orientation of the holding unit 7 is adjusted by driving the θ unit 5 as needed. Next, the aerial transport vehicle 1 drives the lifting drive unit 6 to lower the holding unit 7, places the article 200 on the loading port 300, and the holding unit 7 releases the hold on the flange 201 of the article 200. The aerial transport vehicle 1 drives the lifting drive unit 6 to raise the holding unit 7 to the rising end. Furthermore, the aerial transport vehicle 1 drives the lateral unit 4 to move the holding unit 7 in the exit direction, so that the holding unit 7 is located between the front frame 16 and the rear frame 17.

[0034] like Figure 1 、 Figure 2 、 Figure 3 (a) and Figure 3 As shown in (b), the aerial transport vehicle 1 includes a sensor 10 and a reflector 11. The sensor 10 is a sensor provided on the lifting drive unit 6. The sensor 10 is not particularly limited, and is, for example, a laser rangefinder. The sensor 10 irradiates the laser (light) L toward the reflector 11 at a plurality of irradiation angles within a monitoring range Z including the reflector 11, and detects a plurality of return lights RL reflected by the reflector 11 corresponding to the irradiation. The sensor 10 irradiates the laser L toward the reflector 11 in a manner scanning along the Y direction within the monitoring range Z. The monitoring range Z is an isosceles triangle area with the sensor 10 as a vertex when viewed from the X direction. The sensor 10 is connected to the transport vehicle controller 8. Return light is also called reflected light.

[0035] The reflector 11 is provided on the holding unit 7. As an example, the reflector 11 is provided in the center of the upper portion of the holding unit 7. The reflector 11 is capable of reflecting the laser light L from the sensor 10. The reflector 11 is arranged with its reflective surface facing upward, and is capable of reflecting the laser light L from above upward. When the lifting drive unit 6 is in a horizontal position, the reflector 11 is arranged directly below the sensor 10. There is no particular limitation on the reflector 11, and various reflective components can be used.

[0036] The reflector 11 has a shape whose width in the Y direction varies from the center toward the outside in the X direction. For example, the reflector 11 is a rectangular plate member, arranged with its diagonal lines oriented along the Y direction when viewed from above. The reflector 11 has a shape that is line-symmetrical about an axis passing through the center and along the X direction. The reflector 11 may also have a portion having a constant width in the Y direction. The reflector 11 may be formed of a reflective tape or other components capable of reflecting the laser light L.

[0037] like Figure 4 As shown, the transport vehicle controller 8 includes a processing unit 8A, a determination unit 8B, and a storage unit 8C as functional components. The processing unit 8A determines (identifies) the horizontal and height positions of the holding unit 7 based on the detection results of the plurality of regressive lights RL detected by the sensor 10.

[0038] The processing unit 8A calculates the average angle and average distance of the optical axes of the detected plurality of recurrent lights RL and calculates the position of the holding unit 7 in the Y direction based on the average angle and average distance. The processing unit 8A calculates the position of the holding unit 7 in the X direction based on the pre-stored number of recurrent lights RL and the number of detected recurrent lights RL. When the traverse unit 4 moves the lifting drive unit 6 sideways, the processing unit 8A corrects the horizontal position of the holding unit 7 based on a pre-stored correction value corresponding to the tilt of the lifting drive unit 6. Details of the various processes performed by the processing unit 8A will be described later.

[0039] The determination unit 8B determines whether the horizontal position of the holding unit 7 identified by the processing unit 8A is within an allowable range. The determination unit 8B may also determine whether at least one of the X-direction position and the Y-direction position of the holding unit 7 identified by the processing unit 8A is within an allowable range. The allowable range may be a predetermined fixed width. The allowable range may also be defined based on an angle or width corresponding to the height position of the holding unit 7. The allowable range may be a range in the X direction, a range in the Y direction, or a range encompassing both.

[0040] When the judgment unit 8B judges that the horizontal position of the holding unit 7 identified by the processing unit 8A is not within the allowable range, it can be regarded that the holding unit 7 has shaken beyond the allowable range, and the shaking detection error can be reported by the notification unit (not shown). The judgment result based on the judgment unit 8B can also be sent to an external superior controller. The storage unit 8C stores the horizontal position and the height position of the holding unit 7 identified by the processing unit 8A in a predetermined period according to a time sequence. The predetermined period is not particularly limited and can be a predetermined fixed period or a period that can be changed by the user.

[0041] Next, the pre-process (pre-treatment) before obtaining the horizontal position and the height position of the holding unit 7 will be described. Figure 2As shown, in the initial state where the lateral unit 4 is not tilted, the lifting drive unit 6 is not shaking, and the reflector 11 is present directly below the sensor 10, the sensor 10 irradiates the reflector 11 with a laser L in a scanning manner along the Y direction, and detects a plurality of return lights RL reflected by the reflector 11 in response to the irradiation.

[0042] The processing unit 8A calculates the average angle of the optical axes of the detected multiple regressive light beams RL as the initial average angle α0. For example, the average angle can be the average of the angle of the optical axis of the first regressive light beam RL1 detected first among the detected multiple regressive light beams RL and the angle of the optical axis of the first regressive light beam RL2 detected last among the detected multiple regressive light beams RL. The first regressive light beam RL1 corresponds to the regressive light beam RL detected when the state switches from no regressive light RL detection to a state where regressive light RL is detected. The second regressive light beam RL2 corresponds to the regressive light beam RL detected when the state switches from the state where regressive light RL is detected to a state where no regressive light RL is detected. The initial average angle α0 corresponds to the angle of the optical axis of the laser beam L0 irradiated toward the center of the reflector 11 in the scanning direction of the optical axis in the initial state.

[0043] In addition, if Figure 3 (a) and Figure 3 As shown in (b) of FIG. 1 , the processing unit 8A calculates the number of detected regressive light beams RL as the initial regressive light count. The initial regressive light count corresponds to the range of the reflector 11 where the regressive light beams RL are detected (irradiated by the laser beam L) in the initial state, namely, the detection range H0. The number of detected regressive light beams RL corresponds to the number of optical axes of the detected regressive light beams RL. The processing unit 8A stores the calculated initial angular average α0 and the initial regressive light count in the storage unit 8C.

[0044] Furthermore, if the initial angle average α0 and the initial number of returning lights are obtained in advance using a simulation or other method and stored in the storage unit 8C, the above-mentioned pre-process can be omitted. The reference for the angle is not particularly limited, and the position directly below the sensor 10 (below in the vertical direction) can be set to 0°. The reference for the position of the holding unit 7 in the X direction and the Y direction is not particularly limited, and the position of the holding unit 7 (sensor 10) in the initial state can be set to 0. The reference for the position of the holding unit 7 in the height direction (Z direction) is not particularly limited, and the position of the sensor 10 in the height direction can be set to 0.

[0045] Next, the case of determining the horizontal position and the height position of the holding unit 7 when transferring the article 200 between the loading port 300 located on the side of the rail 20 in a plan view will be described. Figure 5As shown, in this example, the holding unit 7 is shaken in the Y direction, and the reflector 11 is located at a position offset in the Y direction from directly below the sensor 10 .

[0046] First, the sensor 10 irradiates the reflector 11 with laser light L in a scanning manner along the Y direction, and detects the multiple regressing lights RL reflected by the reflector 11 in response to the irradiation. The processing unit 8A calculates the average angle and average distance of the optical axes of the detected multiple regressing lights RL as the transfer angle average α1 and the transfer distance average B1. The average distance can be, for example, the average distance of each optical axis of the multiple regressing lights RL. The distance of the regressing lights RL can be determined based on, for example, the intensity of the regressing lights RL. The transfer angle average α1 corresponds to the angle of the optical axis of the laser light L1 irradiated toward the center of the reflector 11 in the scanning direction of the optical axis during transfer.

[0047] The processing unit 8A calculates the difference β between the initial angle average α0 and the transfer angle average α1, and calculates the position of the holding unit 7 in the Y direction according to the following equation (1) which relates the difference β to the transfer distance average B1. The position of the holding unit 7 in the Y direction corresponds to the amount of play of the holding unit 7 in the Y direction.

[0048] The position of the holding unit 7 in the Y direction = B1·sinβ (1)

[0049] At this time, the position of the holding unit 7 in the horizontal direction is corrected by the processing unit 8A based on the correction value pre-stored in the storage unit 8C. The correction value is a value corresponding to the inclination (posture) of the lifting drive unit 6. The correction value is a value obtained by correcting the initial angle average α0 according to the inclination of the lifting drive unit 6. For example, since the lifting drive unit 6 may be tilted due to the presence or absence of the driving of the transverse unit 4, the driving amount of the transverse unit 4, the type of the loading port 300 of the transfer object, the inclination of the track 20, etc., a correction value associated with at least any one of them is set as a correction value table. As an example, the processing unit 8A obtains the correction value corresponding to the inclination of the lifting drive unit 6 from the correction value table according to the driving amount of the transverse unit 4, and when calculating the position of the holding unit 7 in the Y direction according to the above formula (1), the correction value is added to or subtracted from the initial angle average α0.

[0050] Furthermore, the processing unit 8A calculates the height position of the holding unit 7 based on the average transfer distance B1 and the difference β according to the following formula (2), for example.

[0051] The position of the holding unit 7 in the height direction = B1·cosβ (2)

[0052] In addition, if Figure 6 (a) and Figure 6As shown in (b) of FIG. 1 , the number of detected return lights RL is obtained by the processing unit 8A as the number of return lights during transfer. The number of return lights during transfer corresponds to the range of the reflector 11 where the return light RL is detected during transfer, i.e., the detection range H1. If the scanning position of the laser L is shifted in the X direction from the initial state, the number of return lights during transfer will be different from the initial number of return lights (here, it will be reduced) depending on the shape of the reflector 11 (see FIG. 1 ). Figure 3 (a) and Figure 6 (a)). Therefore, processing unit 8A uses, for example, a conversion coefficient Gx based on the difference between the initial return light number and the return light number during transfer, to determine the position of holding unit 7 in the X direction according to the following formula (3). Conversion coefficient Gx is a coefficient used to convert the difference between the initial return light number and the return light number during transfer into the offset in the X direction, and may be pre-stored in storage unit 8C. The position of holding unit 7 in the X direction corresponds to the amount of shake of holding unit 7 in the X direction.

[0053] The position of the holding unit 7 in the X direction = (initial return light number - return light number during transfer) · Gx (3)

[0054] As described above, in the overhead transfer vehicle 1, when the holding unit 7 is raised or lowered, the height position of the holding unit 7 can be determined while simultaneously quantifying the sway of the holding unit 7 based on the position of the holding unit 7 in the X and Y directions. In other words, the amount of sway of the holding unit 7 can be accurately determined, as well as the height of the holding unit 7. This allows for numerical management of the sway of the holding unit 7.

[0055] In the overhead transport vehicle 1, a reflector 11 is provided on the holding unit 7. A sensor 10 irradiates the reflector 11 with laser light L at various irradiation angles and detects a plurality of regressive beams RL reflected by the reflector 11 in response to the irradiation. Furthermore, the processing unit 8A calculates the horizontal and vertical positions of the holding unit 7 based on the detection results of the sensor 10. In this case, the horizontal and vertical positions of the holding unit 7 can be easily detected using the regressive beams RL.

[0056] In the overhead transport vehicle 1, the sensor 10 irradiates the Y-direction laser beam L toward the reflector 11 within the monitoring range Z. The processing unit 8A calculates the angular average and distance average of the optical axes of the plurality of detected recurrent beams RL and calculates the Y-direction position of the holding unit 7 based on the angular average and distance average. This allows accurate determination of the Y-direction fluctuations of the holding unit 7 and the height of the holding unit 7.

[0057] In the overhead transport vehicle 1, the reflector 11 includes a shape whose width in the Y direction varies as it approaches the X direction. The processing unit 8A calculates the X-direction position of the holding unit 7 based on the pre-stored initial return light count and the transfer return light count. This allows the accurate determination of the X-direction swing of the holding unit 7.

[0058] The overhead transfer vehicle 1 further includes a determination unit 8B that determines whether the horizontal position of the recognized holding unit 7 is within an allowable range. In this case, it is possible to determine whether the amount of shaking of the holding unit 7 is allowable.

[0059] The overhead transfer vehicle 1 includes a lateral unit 4 that moves the lifting drive unit 6 laterally relative to the frame unit 2. This allows accurate understanding of the amount of shaking of the holding unit 7 and the height of the holding unit 7 during lateral transfer, for example.

[0060] In the overhead transfer vehicle 1, when the lifting drive unit 6 is moved sideways by the traverse unit 4, the processing unit 8A corrects the horizontal position of the holding unit 7 based on a pre-stored correction value. This allows accurate detection of the amount of shaking of the holding unit 7 and the height of the holding unit 7, even if the tilt of the lifting drive unit 6 caused by the traverse unit 4 causes the illumination direction of the sensor 10 to tilt. Furthermore, in the overhead transfer vehicle 1, the horizontal position of the holding unit 7 can be corrected based on a correction value corresponding to the tilt of the lifting drive unit 6 caused by the tilt of the track 20. In this case, even if the tilt of the track 20 causes the illumination direction of the lifting drive unit 6 and the sensor 10 to tilt, the amount of shaking of the holding unit 7 and the height of the holding unit 7 can be accurately determined.

[0061] The overhead transport vehicle 1 includes a storage unit 8C that stores the identified horizontal and vertical positions of the holding unit 7 in a time-series manner for a predetermined period. This allows the movement of the holding unit 7 to be monitored and utilized, for example, during maintenance.

[0062] In addition, in the overhead transfer vehicle 1, the following effects are achieved. That is, the movement of the holding unit 7 (the position in the horizontal direction corresponding to the position in the height direction) can be accurately grasped. The absolute position (three-dimensional position) of the holding unit 7 can be accurately grasped. Appropriate control corresponding to the movement of the holding unit 7 can be performed. For example, even in the case where the transfer of the article 200 is stopped due to a shake exceeding the allowable range, control such as automatic recovery after the shake becomes smaller can be performed. The size of the reflector 11 is no longer related to the allowable amount of shake. The size of the reflector 11 can be increased. The amount of shake of the reflector 11 can be calculated in real time by calculation. It is preferable to make the angular resolution of the sensor 10 fine. By taking into account the calculation of the inclination of the lifting drive unit 6 caused by lateral transfer and the inclination of the track 20, it is less likely to be affected by the inclination.

[0063] Although the embodiment has been described above, one aspect of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of one aspect of the present invention.

[0064] In the above embodiment, the shape of the reflector 11 is not particularly limited. The shape of the reflector 11 may be any shape whose width in the Y direction varies as it approaches the X direction. For example, the shape of the reflector 11 may include a polygonal shape, an elliptical shape, an oblong shape, or a combination of these shapes, as long as its width in the Y direction varies as it approaches the X direction.

[0065] In the above embodiment, the recognition device includes the sensor 10, but a stereo camera or other imaging device may be used in place of the sensor 10. In the above embodiment, the transport vehicle controller 8 includes the processing unit 8A, the determination unit 8B, and the storage unit 8C, but some or all of the processing unit 8A, the determination unit 8B, and the storage unit 8C may be mounted on an external computer capable of communicating with the overhead transport vehicle 1.

[0066] The structures in the above-mentioned embodiments and modifications are not limited to the materials and shapes described above, and various materials and shapes can be applied. The structures in the above-mentioned embodiments or modifications can be arbitrarily applied to the structures in other embodiments or modifications. Parts of the structures in the above-mentioned embodiments or modifications can be appropriately omitted without departing from the gist of one embodiment of the present invention. In the above description, the sensor 10 and the processing unit 8A constitute an identification device that identifies the position of the holding unit 7 in the horizontal direction and the position in the height direction.

[0067] Description of Reference Numerals

[0068] 1: Aerial transport vehicle, 2: Frame unit (main body), 4: Horizontal unit (Horizontal transfer mechanism), 6: Lifting drive unit (Lifting drive unit), 7: Holding unit, 8A: Processing unit (Identification device), 8B: Judgment unit, 8C: Storage unit, 10: Sensor, 11: Reflector (Reflective component), 200: Article, 300: Loading port (Loading unit), L: Laser (light), RL: Return light.

Claims

1. An aerial transport vehicle having: a holding unit, the holding unit being configured to be able to rise and fall relative to the main body and to hold an article; a lifting drive unit that causes the holding unit to move up and down; and An identification device is provided for identifying the position of the holding unit in the horizontal direction and the position in the height direction.

2. The overhead transport vehicle according to claim 1, wherein: A reflective plate is provided on the holding unit, The identification device comprises: a sensor provided on the lifting drive unit, configured to irradiate light toward the reflector at a plurality of irradiation angles within a monitoring range including the reflector, and to detect a plurality of return lights reflected by the reflector in response to the irradiation; and A processing unit is configured to obtain a horizontal position and a height position of the holding unit based on detection results of the plurality of returning lights detected by the sensor.

3. The overhead transport vehicle according to claim 2, wherein: When the traveling direction of the overhead transfer vehicle is defined as the X direction and the horizontal direction perpendicular to the X direction is defined as the Y direction, The sensor irradiates light toward the reflector in a manner of scanning along the Y direction within the monitoring range. The processing unit calculates an angle average and a distance average about the optical axes of the plurality of detected returning lights, and calculates a position of the holding unit in the Y direction based on the angle average and the distance average.

4. The overhead transfer vehicle according to claim 3, wherein: The shape of the reflector includes a shape in which the width in the Y direction varies as it approaches the X direction. The processing unit determines the position of the holding unit in the X direction based on the number of the regressive lights stored in advance and the number of the plurality of detected regressive lights.

5. The overhead transfer vehicle according to claim 3 or 4, wherein: The device further includes a determination unit configured to determine whether the horizontal position of the holding unit recognized by the recognition device is within an allowable range.

6. The overhead transfer vehicle according to claim 1 or 2, wherein: A lateral transfer mechanism is provided for moving the lifting drive portion laterally relative to the main body portion.

7. The overhead transfer vehicle according to claim 6, wherein: When the lifting drive unit is moved sideways by the lateral transfer mechanism, the recognition device corrects the horizontal position of the holding unit based on a pre-stored correction value corresponding to the inclination of the lifting drive unit.

8. The overhead transfer vehicle according to claim 1 or 2, wherein: A storage unit is provided for storing the horizontal position and the height position of the holding unit recognized by the recognition device in a time series for a predetermined period.

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