Transfer devices and article conveying devices

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 conveying device.

Background Art

[0002] Conventionally, in an automated warehouse, the conveyance of articles to the shelves of a rack for storing articles has been performed by a stacker crane. In the automated warehouse of Patent Document 1, a main controller determines whether there is already an article in a required article placement section of a shelf based on the detection result of an optical sensor provided on the lift table of the stacker crane, and transfers the conveyed article to the article placement section (transfer position) only when it is determined that there is no article.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when a problem occurs in the detection by the sensor due to a sensor failure or the like, an incorrect determination is made, and there is room for improvement in the determination accuracy of the presence or absence of an article.

[0005] One aspect of the present disclosure aims to provide a transfer device and an article conveying device capable of improving the determination accuracy of the presence or absence of an object.

Means for Solving the Problems

[0006] To solve the above problems, a transfer device according to one aspect of the present disclosure includes a transfer unit that transfers a transported object to a predetermined transfer position, a sensor that detects whether or not there is an object within a detection range in the transfer direction, which is the direction in which the transfer unit transfers the transported object, and a control unit. The control unit performs a first determination process that sets the detection range of the sensor to a first range that includes the transfer position and a first position located further in the transfer direction than the transfer position, and determines whether or not the sensor detects an object, and a second determination process that 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 or not the sensor detects an object. [Effects of the Invention]

[0007] According to one aspect of this disclosure, the accuracy of determining the presence or absence of an article can be improved. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view showing an example of an article handling facility using a stacker crane according to the embodiment of this disclosure. [Figure 2] This is a front view of a stacker crane according to an embodiment. [Figure 3] This is a schematic control block diagram of a stacker crane according to an embodiment. [Figure 4] This flowchart shows an example of the flow of the double loading detection process by the transfer control unit according to the embodiment. [Figure 5] This is a top view showing the positional relationship between the main body of the transfer unit according to the embodiment and the transfer position of the shelf. [Figure 6] This is a top view showing the second range of the distance sensor according to the embodiment. [Figure 7] This is a top view showing the second range of the distance sensor related to the modified example. [Modes for carrying out the invention]

[0009] The embodiments of this disclosure will be described below with reference to Figures 1 to 6.

[0010] [Material handling equipment] Figure 1 is a perspective view showing an example of an article handling facility 8 in which a stacker crane 100 is used. For the sake of explanation, the vertical, horizontal, and left-right directions of the article handling facility 8 are defined as shown by the arrows in Figure 1.

[0011] As shown in Figure 1, the goods transport equipment 8 has multiple shelves 80. The shelves 80 are located on both the front and rear sides of the travel path R on which the stacker crane 100 travels. Each shelf 80 is positioned such that its front side in the depth direction faces the travel path R.

[0012] Each shelf 80 has multiple storage compartments 81 for storing transported goods M. The multiple storage compartments 81 are arranged in multiple tiers in the vertical direction and in multiple rows in the horizontal direction. Each storage compartment 81 has a transfer position for transferring transported goods M. A plate-shaped cover member 81a is erected on the back side of each storage compartment 81 to cover the storage compartment 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 the sake of explanation, the vertical and horizontal directions of the stacker crane 100 are defined as shown by the arrows in Figures 1 and 2. The vertical direction of the stacker crane 100 corresponds to the direction in which the lifting unit 20 moves up and down. The horizontal direction of the stacker crane 100 corresponds to the direction in which the traveling carriage 30 travels.

[0014] As shown in Figures 2 and 3, the stacker crane 100 comprises a pair of masts 11, a transfer unit 10, a lifting unit 20, a traveling carriage 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 conveying device.

[0015] The control device 50 includes a transfer control unit 51, a lifting control unit 52, and a traveling control unit 53. The distance sensor 40, the transfer control unit 51, and the transfer unit 10 constitute the transfer device 1.

[0016] The transfer device 1 is supported by the lifting unit 20. The transfer unit 10 has forks for holding the conveyed object M. When loading the conveyed object M, the transfer unit 10 protrudes the forks in the transfer direction, holds the conveyed object M with the forks up to the transfer position A, places the conveyed object M at the transfer position A, and then retracts the forks.

[0017] As shown in FIG. 2, the pair of masts 11 are fixed to the upper part of the traveling carriage 30. Each mast 11 is spaced apart in the traveling direction of the traveling carriage 30, that is, in the left - right direction, and extends along the vertical direction. Each mast 11 is formed of a vertically long hollow member.

[0018] The upper end portions of the pair of masts 11 are connected to the connecting portion 23. The connecting portion 23 has guide rollers 83. The guide rollers 83 are guided by a guide rail 82 provided on a 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 the pair of masts 11 and moves up and down along the masts 11. The lifting unit 20 is suspended and supported by a plurality of wires 22 wound around a rotating body 24. The lifting unit 20 moves up and down along the masts 11 by driving the lifting motor 21 to rotate the rotating body 24 forward and backward, thereby winding or unwinding the wires 22.

[0020] The traveling carriage 30 travels in the traveling direction, that is, in the left - right direction, along the traveling path R. The traveling path R is formed by a traveling rail 33 disposed 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 Figure 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 travel carriage 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 within the 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 measures the distance from the distance sensor 40 to the object by irradiating a laser beam from the light-emitting unit toward the transfer position A in the transfer direction and receiving the reflected light reflected from the object with the light-receiving unit. The transfer control unit 51 controls the operation of the forks 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 positioned, for example, at the tip of the fork of the transfer unit 10. This makes it possible to accurately measure the distance from the tip of the transfer unit 10 in the transfer direction to the transported object M or other object.

[0026] The lifting sensor 60 is, for example, an optical sensor and is located on the trolley 30. The lifting sensor 60 emits light toward a reflector 61 installed on the underside of the lifting section 20 and detects the distance to the lifting section 20 by receiving the light reflected by the reflector 61.

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

[0028] The running sensor 70 is, for example, an optical distance detection sensor and is located on the running trolley 30. The running sensor 70 emits light toward a reflector 71 fixed to the floor and detects the distance between the running sensor 70 and the reflector 71 by receiving the reflected light from the reflector 71. The running sensor 70 may be located on the upper part of the mast 11 or 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 path 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 travel rail 33 in accordance with the rotation of the first wheel W1 and the second wheel W2.

[0030] [Flowchart of the process for detecting duplicate loading by the transfer control unit] Next, the flow of the double loading detection process by the transfer control unit 51 will be explained with reference to Figures 4 to 6. Figure 4 is a flowchart showing an example of the flow of the double loading detection process by the transfer control unit 51.

[0031] As shown in Figure 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 trolley 30 and the lifting unit 20 to move the transfer unit 10 to just before the desired shelf 80 where the transported object M is stored, and then stops the transfer unit 10.

[0032] Here, Figure 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 Figure 5, the first range includes the transfer position A, the first position P1, and the first non-transferable range B1. The first range is, for example, a range of about 200 mm to 1000 mm when the position of the distance sensor 40 in the transfer direction is set to 0 mm. The transfer direction is the direction in which the transfer unit 10 moves when placing the transported object M.

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

[0034] The first non-transferable range B1 is, for example, the range from approximately 600 mm to 1000 mm from the distance sensor 40, and is the range in which it is impossible to transfer the transported object M. The range beyond 1000 mm is outside the shelf 80. The second non-transferable range B2 is, for example, the range from approximately 0 mm to 200 mm from the distance sensor 40, and is the range in which it is impossible to transfer the transported object M.

[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 transfer control unit 51 detects that the distance sensor 40 has an object, in this case the cover member 81a, within the first range (S2: YES), it 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 a malfunction or other abnormality has occurred in the distance sensor 40, notifies the abnormality of the distance sensor 40 (S4: first error processing), and avoids transferring the transported object M to the transfer position A by the transfer unit 10, thereby ending 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 it may display an error code indicating an abnormality in the distance sensor 40 on a display unit (not shown). After the user confirms the notification of an abnormality in the distance sensor 40, the user takes appropriate action, 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, Figure 6 is a top view showing the second range of the distance sensor 40. As shown in Figure 6, the second range 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 non-transferable range B1 and the second non-transferable range B2. The second range is, for example, a range of about 200 mm to 600 mm when the 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 object M or an obstacle within the second range (S6: YES), the transfer control unit 51 notifies of an abnormality related to double loading (S7: second error processing).

[0040] In step S7, the transfer control unit 51 prevents the transfer of the transported object M to the transfer position A by the transfer unit 10, and does not perform the transfer of the transported object M to the transfer position A by the transfer unit 10. In step S7, the transfer control unit 51 may also output an audio message from the speaker to notify of the abnormality of double loading, or display an error code or the like on the display unit to notify of the abnormality of double loading.

[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 object M or an obstacle at the transfer position A (S8), and transfers the transported object M to the transfer position A using the transfer unit 10 (S9).

[0042] Based on the above, the transfer control unit 51 terminates the double loading detection process shown in Figure 4. When multiple transported items M are stored in different storage sections 81 of shelves 80, the transfer control unit 51 executes the double loading detection process shown in Figure 4 each time a transported item M is moved to the transfer position A of each storage section 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 located at the first position P1 within the first range (S2: NO), it is determined that an abnormality such as a malfunction has occurred in the distance sensor 40, and the abnormality of the distance sensor 40 is reported (S4: first error processing). As a result, the user can quickly grasp that an abnormality has occurred in the distance sensor 40 and take appropriate action.

[0044] Furthermore, in the first error processing (S4), the transfer control unit 51 avoids transferring the transported object M to the transfer position A by the transfer unit 10. This prevents a situation where the transported object 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 there is an object within the second range (S6: second determination process), and if the distance sensor 40 detects an object such as the transported object M or an obstacle within the second range (S6: YES), it notifies of a double transport (S7: second error processing). This allows the user to quickly understand that a double transport has occurred and take appropriate action. Thus, in this embodiment, the transfer control unit 51 switches the detection range of one distance sensor 40 between a first range and a second range and executes the first determination process (S2) and the second determination process (S6), making it possible to improve the accuracy of determining the presence or absence of an object with a simple configuration.

[0046] Furthermore, in the second error processing (S7), the transfer control unit 51 avoids transferring the transported object M to the transfer position A by the transfer unit 10, thereby reliably preventing double loading of the transported object M.

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

[0048] [Other Embodiments] In the embodiment described above, the transfer control unit 51 prevents the transfer of the transported object M to the transfer position A by the transfer unit 10 during the first error processing (S4) and the second error processing (S7), but is not limited to this. For example, the control device 50 may control the operation of the transfer unit 10, the lifting unit 20, and the traveling trolley 30, etc., during the first error processing (S4) and the second error processing (S7) 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 perform the error verification work.

[0049] In the embodiment described above, the second range is defined as the range that includes the transfer position A and does not include the first position P1, the first non-transferable range B1, and the second non-transferable range B2, as shown in Figure 6, but is not limited to this. For example, the second range may be the range that includes the transfer position A and the second non-transferable range B2, but does not include the first position P1 and the first non-transferable range B1, as shown in the modified example in Figure 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 non-transferable range B2, which would be an undetectable range for conventional distance sensors whose detection range cannot be changed, as shown in Figure 7. In this way, by appropriately changing the second range, which is the detection range of the distance sensor 40, taking into account the size of the transfer position A and the second non-transferable range B2, it becomes possible to execute the second determination process (S6) by the transfer control unit 51 more accurately.

[0051] Furthermore, in the embodiment described above, the distance sensor 40 is positioned at the tip of the fork of the transfer unit 10, but it is not limited to this, and may be positioned on the side of the transfer unit 10 that is on the transfer direction side.

[0052] Furthermore, in the embodiment described above, the distance sensor 40 is a laser-type distance sensor, but it is not limited to this, and may be an ultrasonic-type distance sensor, for example. In an ultrasonic-type distance sensor, the distance from the distance sensor to the object is detected based on the emission of ultrasonic waves from the distance sensor towards the object and the reception of ultrasonic waves reflected from the object.

[0053] Furthermore, in the above-described embodiment, the lifting sensor 60 and the travel sensor 70 are optical sensors, but the system is not limited to these. For example, the vertical position of the lifting unit 20 and the travel position of the travel carriage 30 may be detected by providing a rotary encoder that rotates in conjunction with the lifting of the lifting unit 20 and a rotary encoder that rotates in conjunction with the rotation of the first wheel W1 and the second wheel W2 of the travel carriage 30.

[0054] 〔summary〕 A transfer device according to a first aspect of the present disclosure includes a transfer unit for transferring a transported object to a predetermined transfer position, a sensor for detecting whether or not an object is within a detection range in the transfer direction, which is the direction in which the transfer unit transfers the transported object, and a control unit. The control unit performs a first determination process for setting the detection range of the sensor to a first range that includes the transfer position and a first position located further in the transfer direction than the transfer position, and determining whether or not the sensor detects an object, and a second determination process for setting the detection range of the sensor to a second range that includes the transfer position but does not include the first position, and determining whether or not the sensor detects an object.

[0055] According to the transfer device of the first embodiment described above, the control unit can detect a sensor abnormality by determining in the first determination process whether or not the sensor detects an object at a first position within a first range. Furthermore, the control unit can determine in the second determination process whether or not the sensor detects an object within a second range whether or not there is a transported object at the transfer position other than the transported object being transported by the transfer unit.

[0056] In the transfer device according to a second aspect of the present disclosure, in the first aspect, the control unit performs 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 embodiment described above, if the control unit determines in the first determination process that there is no object within the first range of the sensor, it executes a first error process to notify the sensor of an abnormality. This allows the user to quickly understand that an abnormality such as a malfunction has occurred in the sensor and to take appropriate action.

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

[0059] According to the transfer device of the third embodiment described above, the control unit performs a second error process in which it notifies of a duplicate delivery if the sensor detects an object within the second range during the second determination process. This allows the user to quickly understand that a duplicate delivery has occurred and take appropriate action.

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

[0061] According to the article transport device of the fourth embodiment described above, the transfer device can prevent the transported items from being loaded twice.

[0062] In the transfer device according to the fifth aspect of this disclosure, in any of the first to fourth aspects, the control unit avoids transferring the transported object to the transfer position by the transfer unit 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 embodiment described above, in the first determination process, if the sensor does not detect an object at the first position within the first range, the control unit considers that there is a malfunction in the sensor and avoids transferring the transported object to the transfer position. This prevents a situation in which the transported object is not properly transported to the transfer position due to a sensor malfunction. Furthermore, in the second determination process, if the sensor detects an object within the second range, the control unit avoids transferring the transported object to the transfer position by the transfer unit. This prevents double loading of the transported object.

[0064] In the transfer device according to the sixth aspect of this 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 in front of the transfer position in the transfer direction.

[0065] According to the transfer device of the sixth embodiment described above, if the control unit determines in the second determination process that an object is located at a non-transferable position in front of the transfer position in the transfer direction within the second range, the transfer unit avoids transferring the transported object to the transfer position. This makes it possible to detect the presence of an object at a non-transferable position, which was previously undetectable by conventional sensors whose detection range cannot be changed, and more reliably prevents double loading of transported objects.

[0066] In the transfer device according to the seventh aspect of this disclosure, in any of the first to sixth aspects, the sensor has a light-emitting unit that emits light and a light-receiving unit that receives reflected light, and is a distance sensor that 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 embodiment described above, the control unit performs a first determination process and a second determination process using a distance sensor capable of measuring the distance from the sensor to the object, so that it can accurately determine whether or not there is a transported object or an object in a position that obstructs the loading of the transported object.

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

[0069] According to the eighth embodiment of the transfer device described above, by attaching a sensor to the tip of the fork, it is possible to accurately measure the distance from the tip of the transfer device in the transfer direction to the transported object, thereby making it possible to more reliably prevent double loading.

[0070] This disclosure is not limited to the embodiments described above, 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 this disclosure. [Explanation of symbols]

[0071] 1 Transfer equipment 8. Goods handling equipment 10 Transfer Section 11 Mast 20 Lifting section 30 Bogies 40 Distance Sensor 51 Transfer Control Unit 81a Cover member 100 stacker crane P1 1st position M Transported items

Claims

1. A transfer unit that transfers the transported object to a predetermined transfer position, A sensor that detects whether or not there is an object within the detection range in the transfer direction, which is the direction in which the transfer unit transfers the transported object, Control unit and Equipped with, The control unit, The detection range of the sensor is set to a first range that includes the transfer position and a first position located further back in the transfer direction than the transfer position, and a first determination process is performed to determine whether or not the sensor detects an object. A second determination process is performed 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 to determine whether or not the sensor detects an object. A transfer device characterized by performing the following actions.

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

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

4. A transfer device according to any one of claims 1 to 3, A trolley that travels along the route, A mast fixed to the aforementioned traction motor and extending in the vertical direction, A lifting unit that holds the conveyed object and moves up and down along the mast, An article conveying device characterized by being equipped with the following features.

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