Transfer device and article conveyance device

Abstract

To provide a transfer device capable of improving precision of a determination on whether there is an object.SOLUTION: A transfer device comprises a transfer part which transfers a conveyance object, a sensor which detects whether an object is present within a detection range in a transfer direction, and a control part. The control part executes: first determination processing (S2) to set the detection range of the sensor to a first range (S1) and then determine whether the sensor detects the object; and second determination processing (S6) to set the detection range of the sensor to a second range (S5) and then determine whether the sensor detects the object.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a transfer device and an article transport device. [Background technology]

[0002] Conventionally, in automated warehouses, transport of goods to shelves of racks where the goods are stored is carried out by a stacker crane. In the automated warehouse of Patent Document 1, the main controller determines whether or not a goods is already present in a required goods placement section of the shelf based on the detection results of an optical sensor provided on the lifting platform of the stacker crane, and is configured to transfer the transported goods to that goods placement section (transfer position) only when it determines that no goods are present. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5252084 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if a problem occurs in the detection by the sensor due to a sensor failure or other reason, an erroneous determination will be made, and there is room for improvement in the accuracy of determining whether or not an article is present.

[0005] An object of one aspect of the present disclosure is to provide a transfer device and an article transport device that can improve the accuracy of determining the presence or absence of an object. [Means for solving the problem]

[0006] In order to solve the above problem, a transfer device according to one aspect of the present disclosure includes a transfer unit that transfers an object to a predetermined transfer position, a sensor that detects whether an object is present within a detection range in a transfer direction in which the transfer unit transfers the object, and a control unit. The control unit sets the detection range of the sensor to a first range that includes the transfer position and a first position that is further back than the transfer position in the transfer direction, and executes a first determination process to determine whether the sensor detects an object, and a second determination process to set the detection range of the sensor to a second range that includes the transfer position but does not include the first position, and determines whether the sensor detects an object. [Effects of the Invention]

[0007] According to one aspect of the present disclosure, it is possible to improve the accuracy of determining whether an item is present or absent. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view illustrating an example of an article transport facility in which a stacker crane according to an embodiment of the present disclosure is used. FIG. [Figure 2] FIG. 1 is a front view of a stacker crane according to an embodiment. [Figure 3] FIG. 2 is a schematic control block diagram of the stacker crane according to the embodiment. [Figure 4] 10 is a flowchart showing an example of the flow of a double carry-in detection process performed by a transfer control unit according to the embodiment. [Figure 5] 10 is a top view showing the positional relationship between the main body of the transfer unit and the transfer position of the shelf according to the embodiment. FIG. [Figure 6] FIG. 10 is a top view showing a second range of the distance sensor according to the embodiment. [Figure 7] FIG. 10 is a top view showing a second range of a distance sensor according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to FIGS.

[0010] [Goods transport equipment] Fig. 1 is a perspective view showing an example of an article transport facility 8 in which a stacker crane 100 is used. For ease of explanation, the up-down direction, front-rear direction, and left-right direction of the article transport facility 8 are defined as shown by the arrows in Fig. 1.

[0011] As shown in Fig. 1, the article transport equipment 8 has a plurality of shelves 80. The shelves 80 are arranged on both the front and rear sides of the travel route R along which the stacker crane 100 travels. Each shelf 80 is arranged so that the front side in the depth direction of the shelf 80 is on the travel route R side.

[0012] Each shelf 80 has a plurality of storage sections 81 for storing the transported items M. The plurality of storage sections 81 are arranged in a plurality of stages in the vertical direction and in a plurality of rows in the horizontal direction. Each storage section 81 has a transfer position for transferring the transported items M. A plate-shaped cover member 81a that covers the storage section 81 is erected at the back side of each storage section 81.

[0013] [Stacker crane] Next, the stacker crane 100 will be described with reference to Figures 2 and 3. Figure 2 is a front view of the stacker crane 100. Figure 3 is a schematic control block diagram of the stacker crane 100. For ease of explanation, the up-down direction and left-right direction of the stacker crane 100 are defined as shown by the arrows in Figures 1 and 2. The up-down direction of the stacker crane 100 corresponds to the direction in which the lifting section 20 moves up and down. Furthermore, the left-right direction of the stacker crane 100 corresponds to the direction in which the traveling carriage 30 travels.

[0014] 2 and 3, the stacker crane 100 includes a pair of masts 11, a transfer unit 10, a lifting unit 20, a traveling cart 30, a distance sensor 40, a control device 50, a lifting sensor 60, and a traveling sensor 70. The stacker crane 100 is an example of an article transport device.

[0015] The control device 50 has a transfer control section 51, a lift control section 52, and a travel control section 53. The distance sensor 40, the transfer control section 51, and the transfer section 10 constitute the transfer device 1.

[0016] The transfer device 1 is supported by a lifting unit 20. The transfer unit 10 has forks that hold the transported object M. When transporting the transported object M, the transfer unit 10 extends the forks in the transfer direction, holds the transported object M with the forks until it reaches the transfer position A, places the transported object M at the transfer position A, and then retracts the forks.

[0017] As shown in Fig. 2, a pair of masts 11 are fixed to the upper part of the traveling carriage 30. The masts 11 extend in the vertical direction, spaced apart from each other in the traveling direction of the traveling carriage 30, i.e., in the left-right direction. Each mast 11 is formed of a hollow member that is long in the vertical direction.

[0018] The upper ends of the pair of masts 11 are connected to a connecting portion 23. The connecting portion 23 has a guide roller 83. The guide roller 83 is guided by a guide rail 82 provided on the ceiling (not shown). The connecting portion 23 is configured to be movable in the left-right direction while being guided by the guide rail 82.

[0019] The lifting unit 20 is supported by a pair of masts 11 and moves up and down along the masts 11. The lifting unit 20 is supported by being suspended by a plurality of wires 22 wound around a rotating body 24. The lifting motor 21 is driven to rotate the rotating body 24 forward and backward, thereby winding or unwinding the wires 22, causing the lifting unit 20 to move up and down along the masts 11.

[0020] The traveling carriage 30 travels in a traveling direction, i.e., left and right, along a traveling path R. The traveling path R is formed by traveling rails 33 arranged on the floor surface. The traveling carriage 30 has a first wheel W1 driven by a first motor 31 and a second wheel W2 driven by a second motor 32.

[0021] The control device 50 controls various operations of the stacker crane 100. As shown in FIG. 3, the control device 50 is electrically connected to the distance sensor 40, the lifting sensor 60, and the travel sensor 70.

[0022] The transfer control unit 51 of the control device 50 controls the operation of the transfer unit 10 based on the detection result of the distance sensor 40. The lifting control unit 52 controls the operation of the lifting unit 20 based on the detection result of the lifting sensor 60. The travel control unit 53 controls the operation of the traveling cart 30 based on the detection result of the travel sensor 70.

[0023] The distance sensor 40 is, for example, a triangulation type laser distance sensor. The distance sensor 40 is an example of a sensor that detects whether or not an object is present within a detection range in the transfer direction. The distance sensor 40 has a light-emitting unit that emits laser light and a light-receiving unit that receives reflected light.

[0024] The distance sensor 40 emits laser light from the light-emitting unit toward the transfer position A in the transfer direction, and measures the distance from the distance sensor 40 to the object based on the light reflected from the object being received by the light-receiving unit. The transfer control unit 51 controls the operation of the fork of the transfer unit 10 by controlling the drive of a transfer motor (not shown) based on the detection result of the distance sensor 40.

[0025] Furthermore, the distance sensor 40 is disposed, for example, at the tip of the fork of the transfer unit 10. Therefore, it is possible to measure the accurate distance from the tip of the transfer unit 10 in the transfer direction to the transported item M or object.

[0026] The lifting sensor 60 is, for example, an optical sensor, and is arranged on the traveling carriage 30. The lifting sensor 60 emits light toward a reflector 61 installed on the underside of the lifting unit 20, and receives the light reflected by the reflector 61, thereby detecting the distance to the lifting unit 20.

[0027] The lift control unit 52 controls the vertical position of the lift unit 20 by controlling the driving of the lift motor 21 based on the detection result of the lift sensor 60. Note that the lift sensor 60 may be provided on the lift unit 20, and the reflector 61 may be provided on the traveling carriage 30.

[0028] The travel sensor 70 is, for example, an optical distance detection sensor, and is disposed on the travel carriage 30. The travel sensor 70 emits light toward a reflector 71 fixed to the floor surface and receives the light reflected from the reflector 71, thereby detecting the distance between the travel sensor 70 and the reflector 71. Note that the travel sensor 70 may be disposed on the upper part of the mast 11 or on the connecting part 23, and the reflector 71 may be fixed to the ceiling.

[0029] The travel control unit 53 determines the position of the stacker crane 100 on the travel route R based on the detection results of the travel sensor 70. The travel control unit 53 then controls the rotation of the first wheel W1 by controlling the drive of the first motor 31, and controls the rotation of the second wheel W2 by controlling the drive of the second motor 32. The traveling carriage 30 travels on the traveling rail 33 in accordance with the rotation of the first wheel W1 and the second wheel W2.

[0030] [Duplicate delivery detection process by the transfer control unit] Next, the flow of the double carry-in detection process by the transfer control unit 51 will be described with reference to Fig. 4 to Fig. 6. Fig. 4 is a flowchart showing an example of the flow of the double carry-in detection process by the transfer control unit 51.

[0031] 4, first, the transfer control unit 51 sets the detection range of the distance sensor 40 to a first range (S1). Before the transfer control unit 51 executes step S1, the control device 50 controls the traveling carriage 30 and the lifting unit 20 to move the transfer unit 10 to just before the desired shelf 80 where the transported article M is stored, and then stops the transfer unit 10.

[0032] 5 is a top view showing the positional relationship between the main body of the transfer unit 10 and the transfer position A on the shelf 80. As shown in FIG. 5, the first range is a range that includes the transfer position A, the first position P1, and the first non-transfer range B1. When the position of the distance sensor 40 in the transfer direction is set to 0 mm, the first range is, for example, a range of approximately 200 mm to 1000 mm. The transfer direction is the direction in which the transfer unit 10 moves when placing the transported item M.

[0033] The first position P1 is located further in the transfer direction than the transfer position A, and is a position where the cover member 81a is disposed. The first position P1 is located, for example, about 800 mm from the distance sensor 40 in the transfer direction.

[0034] The first transfer-prohibited range B1 is, for example, a range of approximately 600 mm to 1000 mm from the distance sensor 40, and is a range into which the transported item M cannot be transferred. Note that a range of 1000 mm or more is outside the shelf 80. The second transfer-prohibited range B2 is, for example, a range of approximately 0 mm to 200 mm from the distance sensor 40, and is a range into which the transported item M cannot be transferred.

[0035] After step S1, the transfer control unit 51 determines whether the distance sensor 40 detects an object within the first range (S2: first determination process). In step S2, if the distance sensor 40 detects that an object, in this case the cover member 81a, is present within the first range (S2: YES), the transfer control unit 51 determines that the distance sensor 40 is operating normally (S3).

[0036] On the other hand, in step S2, if the distance sensor 40 does not detect an object, in this case the cover member 81a, within the first range (S2: NO), the transfer control unit 51 determines that an abnormality such as a breakdown has occurred in the distance sensor 40, reports the abnormality in the distance sensor 40 (S4: first error processing), prevents the transfer unit 10 from transferring the transported item M to the transfer position A, and ends the flow shown in Figure 4.

[0037] In step S4, the transfer control unit 51 may output an error sound from a speaker (not shown) or may display an error code or the like on a display unit (not shown) to notify the user of an abnormality in the distance sensor 40. After confirming the notification of an abnormality in the distance sensor 40, the user takes appropriate measures such as replacing the distance sensor 40.

[0038] Next, after step S3, the transfer control unit 51 sets the detection range of the distance sensor 40 to a second range (S5). Here, FIG. 6 is a top view showing the second range of the distance sensor 40. As shown in FIG. 6, the second range is a range that includes the transfer position A but does not include the first position P1. The second range is narrower than the first range and does not include the first transfer-prohibited range B1 or the second transfer-prohibited range B2. The second range is, for example, a range of approximately 200 mm to 600 mm when the placement position of the distance sensor 40 in the transfer direction is set to 0 mm.

[0039] After step S5, the transfer control unit 51 determines whether the distance sensor 40 detects an object within the second range (S6: second determination process). In step S6, if the distance sensor 40 detects an object such as the transported article M or an obstacle within the second range (S6: YES), the transfer control unit 51 notifies an abnormality regarding double carrying-in (S7: second error process).

[0040] In step S7, the transfer control unit 51 prevents the transfer unit 10 from transferring the transported item M to the transfer position A, and does not execute the transfer of the transported item M to the transfer position A by the transfer unit 10. Also, in step S7, the transfer control unit 51 may output a sound from the speaker to notify the abnormality of double transport, or may display an error code or the like on the display unit to notify the abnormality of double transport.

[0041] On the other hand, in step S6, if the distance sensor 40 does not detect an object within the second range (S6: NO), the transfer control unit 51 determines that there is no object such as the transported item M or an obstacle at the transfer position A (S8), and transfers the transported item M to the transfer position A by the transfer unit 10 (S9).

[0042] With the above, the transfer control unit 51 ends the double-carry-in detection process shown in Fig. 4. When storing multiple transported items M in the storage units 81 of different shelves 80, the transfer control unit 51 executes the double-carry-in detection process shown in Fig. 4 each time it transfers each transported item M to the transfer position A of each storage unit 81.

[0043] According to the stacker crane 100 equipped with the transfer device 1 of this embodiment described above, the transfer control unit 51 sets the detection range of the distance sensor 40 to a first range (S1), executes a first determination process (S2), and if the distance sensor 40 does not detect the cover member 81a arranged at the first position P1 within the first range (S2: NO), it determines that an abnormality such as a breakdown has occurred in the distance sensor 40, and notifies the user of the abnormality in the distance sensor 40 (S4: first error process). This allows the user to quickly recognize that an abnormality has occurred in the distance sensor 40, and to take appropriate measures.

[0044] Furthermore, in the first error processing (S4), the transfer control unit 51 prevents the transfer unit 10 from transferring the transported item M to the transfer position A. This makes it possible to avoid a situation in which the transported item M is not properly transported to the transfer position A due to an abnormality in the distance sensor 40.

[0045] Furthermore, the transfer control unit 51 sets the detection range of the distance sensor 40 to a second range (S5), determines whether or not an object is present within the second range (S6: second determination process), and if the distance sensor 40 detects an object such as the transported article M or an obstacle within the second range (S6: YES), notifies the user of a double carry-in (S7: second error process). This allows the user to quickly recognize that a double carry-in has occurred and take appropriate action. In this way, in this embodiment, the transfer control unit 51 switches the detection range of one distance sensor 40 between the first range and the second range, and executes the first determination process (S2) and the second determination process (S6), thereby improving the accuracy of determining whether or not an object is present with a simple configuration.

[0046] Furthermore, the transfer control unit 51 prevents the transfer unit 10 from transferring the article M to the transfer position A in the second error processing (S7), so that double delivery of the article M can be reliably prevented.

[0047] Furthermore, the transfer control unit 51 executes the first determination process (S2) and the second determination process (S6) using a laser distance sensor that can measure the distance from the distance sensor 40 to the object. This allows the transfer control unit 51 to more accurately determine whether or not the transported object M or an object such as an obstacle is in a position that obstructs the transport of the transported object M.

[0048] Other Embodiments In the above embodiment, the transfer control unit 51 prevents the transfer unit 10 from transferring the object M to the transfer position A in the first error processing (S4) and the second error processing (S7), but this is not limited to this. For example, in the first error processing (S4) and the second error processing (S7), the control device 50 may control the operations of the transfer unit 10, the lifting unit 20, the traveling cart 30, etc. to move the transfer unit 10 from the shelf 80 where the error was reported to another position. This makes it easier for the user to check the error.

[0049] In the above embodiment, the second range is a range that includes the transfer position A and does not include the first position P1, the first transfer-prohibited range B1, and the second transfer-prohibited range B2, as shown in Fig. 6. However, the second range is not limited to this. For example, the second range may be a range that includes the transfer position A and the second transfer-prohibited range B2 and does not include the first position P1 and the first transfer-prohibited range B1, as shown in a modified example of Fig. 7.

[0050] As described above, by setting the detection range of the distance sensor 40 to the second range, it becomes possible to detect the presence or absence of the transported object M in the second transfer-prohibited range B2, which is an undetectable range with a conventional distance sensor whose detection range cannot be changed, as shown in Fig. 7. In this way, by appropriately changing the second range, which is the detection range of the distance sensor 40, taking into account the sizes of the transfer position A and the second transfer-prohibited range B2, it becomes possible to more accurately execute the second determination process (S6) by the transfer control unit 51.

[0051] Furthermore, in the above embodiment, the distance sensor 40 is arranged at the tip of the fork of the transfer unit 10, but this is not limited to this, and it may also be arranged, for example, on the surface of the transfer unit 10 facing the transfer direction.

[0052] In the above embodiment, the distance sensor 40 is a laser distance sensor, but it is not limited to this and may be, for example, an ultrasonic distance sensor. An ultrasonic distance sensor detects the distance from the distance sensor to an object by transmitting ultrasonic waves toward the object and receiving the ultrasonic waves reflected from the object.

[0053] In the above embodiment, the lifting sensor 60 and the traveling sensor 70 are optical sensors, but are not limited to this. For example, the vertical position of the lifting unit 20 and the position of the traveling cart 30 in the traveling direction may be detected by providing a rotary encoder that rotates as the lifting unit 20 moves up and down and a rotary encoder that rotates as the first wheel W1 and second wheel W2 of the traveling cart 30 rotate.

[0054] 〔summary〕 A transfer device according to a first aspect of the present disclosure includes a transfer unit that transfers an object to a predetermined transfer position, a sensor that detects whether an object is present within a detection range in a transfer direction in which the transfer unit transfers the object, and a control unit. The control unit executes a first determination process in which the detection range of the sensor is set to a first range that includes the transfer position and a first position that is further back than the transfer position in the transfer direction and determines whether the sensor detects an object, and a second determination process in which the control unit sets the detection range of the sensor to a second range that includes the transfer position but does not include the first position and determines whether the sensor detects an object.

[0055] According to the transfer device of the first aspect, the control unit can detect an abnormality in the sensor by determining in the first determination process whether the sensor detects an object at a first position within a first range. Also, the control unit can determine in the second determination process whether the sensor detects an object within a second range whether there is an object other than the object being transferred by the transfer unit at the transfer position.

[0056] In the transfer device according to the second aspect of the present disclosure, in the first aspect, the control unit executes a first error process to notify of an abnormality in the sensor if the sensor does not detect an object in the first determination process.

[0057] According to the transfer device of the second aspect, when the sensor determines in the first determination process that there is no object within the first range, the control unit executes a first error process to notify the user of a sensor abnormality, thereby enabling the user to quickly recognize that an abnormality such as a failure has occurred in the sensor and to take appropriate measures.

[0058] In the transfer device according to the third aspect of the present disclosure, in the first or second aspect, if the sensor detects an object in the first determination process and the sensor detects an object in the second determination process, the control unit executes a second error process to notify of double entry.

[0059] According to the transfer device of the third aspect, when the sensor detects an object within the second range in the second determination process, the control unit executes a second error process to notify the user of the occurrence of a double carry-in, thereby enabling the user to quickly recognize that a double carry-in has occurred and take appropriate measures.

[0060] An article transport device according to a fourth aspect of the present disclosure comprises a transfer device according to any one of the first to third aspects, a traveling carriage that travels along a travel path, a mast that is fixed to the traveling carriage and extends in the vertical direction, and a lifting section that holds the transported article and moves up and down along the mast.

[0061] According to the article transport device of the fourth aspect, the transfer device can prevent double transport of the article.

[0062] In the transfer device according to the fifth aspect of the present disclosure, in any of the first to fourth aspects, the control unit prevents the transfer unit from transferring the transported object to the transfer position if the sensor does not detect an object in the first determination process, or if the sensor detects an object in the second determination process.

[0063] According to the transfer device of the fifth aspect, if the sensor does not detect an object at a first position within a first range in the first determination process, the control unit determines that an abnormality has occurred in the sensor and prevents the transfer of the object to the transfer position. This makes it possible to avoid a situation in which the object is not properly transferred to the transfer position due to a sensor abnormality. Furthermore, if the sensor detects an object within a second range in the second determination process, the control unit prevents the transfer unit from transferring the object to the transfer position. This makes it possible to prevent duplicate delivery of the object.

[0064] In a transfer device according to a sixth aspect of the present disclosure, in any of the first to fifth aspects, the second range further includes a position where the transported object cannot be transferred, which is located before the transfer position in the transfer direction.

[0065] According to the transfer device of the sixth aspect, when the control unit determines in the second determination process that an object is present in a non-transferable position within the second range on the near side in the transfer direction of the transfer position, the control unit prevents the transfer unit from transferring the object to the transfer position. This makes it possible to detect the presence of an object in the non-transferable position, which was an undetectable range for a conventional sensor whose detection range cannot be changed, and more reliably prevents double delivery of the object.

[0066] In the transfer device according to the seventh aspect of the present disclosure, in any of the first to sixth aspects, the sensor is a distance sensor having a light-emitting unit that emits light and a light-receiving unit that receives reflected light, and irradiates light from the light-emitting unit toward the transfer position in the transfer direction, receives the reflected light reflected by the object with the light-receiving unit, and measures the distance from the sensor to the object.

[0067] According to the transfer device of the seventh aspect, the control unit performs the first judgment process and the second judgment process using a distance sensor capable of measuring the distance from the sensor to the object, thereby making it possible to accurately determine whether or not there is an object or transported object in a position that would obstruct the transport of the object.

[0068] In a transfer device according to an eighth aspect of the present disclosure, in any of the first to seventh aspects, the transfer device has a fork for holding the transported object, and the sensor is arranged at the tip of the fork.

[0069] According to the transfer device of the eighth aspect, by attaching a sensor to the tip of the fork, it is possible to measure the exact distance from the tip of the transfer device in the transfer direction to the transported item, making it possible to more reliably prevent double loading.

[0070] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present disclosure. [Explanation of symbols]

[0071] 1 Transfer equipment 8. Goods transport equipment 10 Transfer section 11 Mast 20 Lifting section 30 Traveling cart 40 Distance Sensor 51 Transfer control unit 81a Cover member 100 stacker crane P1 1st position M Transported item

Claims

1. a transfer unit that transfers the object to a predetermined transfer position; a sensor that detects whether or not an object is present within a detection range in a transfer direction in which the transfer unit transfers the transported object; A control unit; Equipped with The control unit a first determination process of setting the detection range of the sensor to a first range including the transfer position and a first position that is further to the rear of the transfer position in the transfer direction, and determining whether the sensor detects an object; a second determination process of setting the detection range of the sensor to a second range that includes the transfer position and does not include the first position, and determining whether the sensor detects an object; A transfer device characterized by performing the above.

2. The control unit 2. The transfer device according to claim 1, wherein, if the sensor does not detect an object in the first determination process, a first error process is executed to notify an abnormality in the sensor.

3. The control unit 3. The transfer device according to claim 2, wherein if the sensor detects an object in the first determination process and if the sensor detects an object in the second determination process, a second error process is executed to notify of a double entry.

4. The transfer device according to any one of claims 1 to 3; a traveling vehicle that travels along a travel route; a mast fixed to the traveling carriage and extending in the vertical direction; a lifting unit that holds the transported object and moves up and down along the mast; An article transport device comprising:

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