JP2009292560A - Conveying vehicle, and cargo transfer method of conveying vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent any abnormal stop of conveying work caused by slight deviation of a cargo when transferring the cargo by a conveying vehicle. <P>SOLUTION: A stacker crane 3 is a conveying vehicle which loads and conveys a cargo W between an article storage shelf 13 and itself, and comprises a traveling truck 23, an elevating/lowering stand 27, a slide fork 29, a deviation detection arm 35, and a control unit. The elevating/lowering stand 27 is mounted on the traveling truck 23. The slide fork 29 can transfer the cargo W to the article storage shelf 13. The deviation detection arm 35 detects the deviation in the traveling direction of the cargo W transferred to the elevating/lowering stand 27 from the article storage shelf 13. The control unit performs the control to transfer the cargo W to the article storage shelf 13 by the slide fork 29 when the deviation is in a permissible range, and then, to make the traveling truck 23 travel by the compensation quantity so as to compensate the deviation, and further, transfer the cargo W from the article storage shelf 13 to the elevating/lowering stand 27 by the slide fork 29. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a transport vehicle and a load transfer method for a transfer vehicle, for example, a stacker crane of an automatic warehouse and a load transfer method thereof.

  A conventional automatic warehouse includes, for example, a pair of racks provided at predetermined intervals in the front-rear direction, a stacker crane provided movably in the left-right direction between the front and rear racks, and a side of one rack. And a loading station arranged on the side of the other rack. The rack has a large number of luggage storage shelves vertically and horizontally. The stacker crane has a traveling carriage, a lifting platform that can be raised and lowered on a mast provided therein, and a load transfer device (for example, a slide fork that is slidable in the front-rear direction). (For example, refer to Patent Document 1).

In a stacker crane, when transferring a load from a shelf to a lift, it is important that the load is arranged at a predetermined position of the lift. This is because if the load protrudes from a predetermined position, the load may collide with the left and right racks. Therefore, conventionally, a photoelectric switch composed of a light projecting element and a light receiving element is provided as a deviation detecting device to detect the deviation of the load on the lifting platform. When the deviation of the load is detected, the conveyance work is abnormally stopped at that time. Then, the worker checks the load on the elevator platform and the deviation detection device, operates the slide fork by manual operation, for example, to eliminate the deviation, and resumes the transfer operation. In this way, it is not efficient to carry out an abnormal stop and check / reset every time a load deviation is detected.
JP 2003-246415 A

  In the stacker crane described in Patent Document 1, photoelectric sensors are provided on both sides of the lifting platform in the transfer direction (before and after the traveling direction of the traveling carriage) to monitor the deviation in the traveling direction of the load. In addition, this stacker crane prevents the transport operation from abnormally stopping due to a slight misalignment of the load.If a misalignment is detected during the pull-in of the slide fork, the slide fork is returned to the opposite side of the pull-in direction. A control method for determining whether or not is slight is adopted.

With this control method, it is possible to cancel the false detection when the protective film or tag of the luggage temporarily protrudes, but the luggage exceeding the specified size is taken into the lifting platform and detected by the displacement detection sensor. In this case, even if the load is lightly collapsed, the conveyance work is abnormally stopped.
SUMMARY OF THE INVENTION An object of the present invention is to prevent the conveyance operation from being abnormally stopped due to a slight deviation of the load when the transfer vehicle transfers the load.

  A transport vehicle according to the present invention is a transport vehicle that can transfer a load to and from a load placement unit, and loads and transports the load, and includes a travel unit, a storage unit, and a transfer unit. , A detection means, a determination means, and a control unit. The storage unit is mounted on the traveling unit. The transfer unit can transfer the load between the storage unit and the load mounting unit. The detecting means detects a shift amount in the traveling direction of the load transferred from the load placement portion to the storage portion. The determination means determines whether or not the deviation amount is within a range that can be stored in the storage unit. When the deviation amount is within an allowable range, the control unit moves the load to the transfer unit from the storage unit to the load placement unit, and then causes the travel unit to travel the compensation amount so as to compensate the deviation amount. Further, the transfer unit is controlled to transfer the load from the load storage unit to the storage unit.

  In this transport vehicle, since the detection means detects the amount of deviation of the load in the traveling direction, it can be determined whether or not the amount of deviation is within an allowable range. Furthermore, since the transfer unit transfers the load to the storage unit after the travel unit has traveled the compensation amount corresponding to the shift amount, even if there is a slight shift of the load, an abnormal stop does not occur. Note that “displacement” refers to a case where the luggage is collapsed, and a part of the luggage protrudes from a predetermined range of the storage unit.

The transport vehicle preferably further comprises means for storing a predetermined maximum dimension of the luggage. The determination means also determines whether or not the maximum package size is exceeded based on the deviation amount. The control unit controls the traveling unit to travel at a low speed when the maximum baggage size is exceeded.
In this transport vehicle, the load can be stably transported by traveling at a low speed when the load exceeds the maximum dimension.

It is preferable that the transport vehicle further includes a storage unit that stores the compensation amount. When the load is transferred to another load placement unit after the deviation of the load is detected and further compensated, the control unit moves the other load load by running the running unit based on the stored compensation amount. Compensation is performed on the placement unit, and then the load is transferred from the storage unit to another load placement unit by the transfer unit.
In this transport vehicle, when the load is transferred to another load placement unit, the stop position of the traveling unit is changed from the normal position by the compensation amount. Thereby, for example, the center of the pallet on which the load is placed can be aligned with the center of the other load placement portion.

A method for transferring a load on a transport vehicle according to the present invention includes a travel unit, a storage unit mounted on the travel unit, and a transfer unit capable of transferring a load between the load mounting unit and the storage unit. A method for transferring a load on a transport vehicle, which includes the following steps.
◎ Step to transfer the load to the storage unit from the load placement unit to the storage unit ◎ Step to detect the shift amount of the load placed in the storage unit in the running direction ◎ Whether the shift amount is within the allowable range ◎ If the amount of deviation is within the allowable range, transfer the load to the transfer unit from the storage unit to the load placement unit, and then run the compensation amount so that the travel unit compensates for the amount of deviation. Next, the step of transferring the load to the transfer section from the load storage section to the storage section. In this load transfer method of the transport vehicle, the shift amount in the traveling direction of the load is detected. It can be determined whether or not is within an allowable range. Furthermore, since the transfer unit transfers the load to the storage unit after the travel unit has traveled the compensation amount corresponding to the shift amount, even if there is a slight shift of the load, an abnormal stop does not occur.

  In the transport vehicle according to the present invention, when the transport vehicle transfers the load, it is not necessary to abnormally stop the transport operation due to a slight shift of the load.

(1) Whole automatic warehouse Hereinafter, the automatic warehouse 1 as one Embodiment which concerns on this invention is demonstrated. In addition, in this embodiment, the up-down direction of FIG. 1 is the front-back direction of the automatic warehouse 1, and the left-right direction of FIG.
The automatic warehouse 1 is mainly composed of a pair of racks 2 and a stacker crane 3.
(2) Racks The pair of racks 2 are arranged so as to sandwich the stacker crane passage 5 extending in the left-right direction in FIG. The rack 2 is provided on a large number of front columns 7 arranged on the left and right sides at a predetermined interval, a rear column 9 arranged behind the front columns 7 with a predetermined interval therebetween, and the front and rear columns 7, 9. A large number of load bearing members 11 are provided. A luggage storage shelf 13 is constituted by a pair of left and right luggage support members 11. As is apparent from the figure, the luggage W can be placed on each luggage storage shelf 13. Each load W is placed on a pallet P (see FIGS. 8 and 9) and moved together with the pallet P. In addition, between the pair of left and right luggage support members 11 is a fork passage gap 15 that allows a slide fork 29 described later to move in the vertical direction.

(3) Stacker Crane A pair of upper and lower guide rails 21 are provided along the stacker crane passage 5, and the stacker crane 3 is guided by these guide rails 21 so as to be movable left and right. The stacker crane 3 is slid in the front-rear direction by a traveling carriage 23, a lifting platform 27 mounted on a pair of left and right masts 25 provided on the traveling carriage 23, and a lifting mechanism 27 (not shown). The slide fork 29 is provided so as to be movable.
The lifting platform 27 includes a placement portion 31 and left and right wall portions 33 extending upward therefrom. Further, the lifting platform 27 is provided with shift detection arms 35 on both the left and right sides. The deviation detection arm 35 is a rod-like member that is supported so as to be rotatable about an axis extending in the vertical direction. An angle sensor 37 (FIG. 4) for detecting the rotation angle is connected to the deviation detection arm 35. Thus, when the load W rotates the shift detection arm 35, the angle sensor 37 can detect the rotation angle and detect the shift amount.

  Next, the control part 51 of the stacker crane 3 is demonstrated using FIG. The control unit 51 is mounted on each stacker crane 3 and can communicate with a controller 52 that controls the entire automatic warehouse 1. The control unit 51 is realized by computer hardware such as a CPU and a memory, but in FIG. 4, it is expressed by a functional configuration realized by cooperation of the computer hardware and software. The control unit 51 includes computer hardware such as a CPU and a memory. In FIG. 4, the control unit 51 is expressed as a functional block realized by the cooperation of the computer hardware and software.

  The control unit 51 includes a travel control unit 53, a lift control unit 55, a transfer control unit 57, and a deviation amount determination unit 71. The traveling control unit 53 is a control unit for controlling the traveling / stopping of the traveling carriage 23, and is connected to the traveling motor 59 and the rotary encoder 61. The lifting control unit 55 is a control unit for moving the lifting platform 27 up and down along the mast 25, and is connected to the lifting motor 63 and the rotary encoder 65. The transfer control unit 57 is a control unit for moving the slide fork 29 in the front-rear direction, and is connected to a transfer motor 67 and a rotary encoder 69. The deviation amount determination unit 71 is a determination unit that determines the presence / absence and amount of deviation of the load loaded on the lifting platform 27, and is connected to the angle sensor 37. Further, the deviation amount determination unit 71 includes a storage unit 73 for storing the deviation amount.

(4) Station A warehouse station 17 is arranged on the left side of the front rack 2, and a warehouse station 19 is arranged on the left side of the rear rack 2. Since the entry station 17 and the exit station 19 have the same structure, only the exit station 19 will be described below.
As shown in FIG. 8B, the unloading station 19 includes a base 41, a pair of left and right side walls 43 extending upward from the base 41, and a pair of loading platforms 45 provided inside the front end of the side wall 43. Yes. Further, a guide member 47 having a guide surface spreading outward is provided at the upper end of the side wall 43. Note that a space between the pair of loading platforms 45 is a passage gap of the slide fork 29.

(5) Basic Operation The basic operation of the stacker crane 3 of the automatic warehouse 1 will be described using the flowchart of FIG. The traveling / elevating / transferring operation of the stacker crane 3 is executed by the control unit, motor, and sensor shown in FIG. 4, but in the following description, the operation of the above configuration is not clearly shown for the sake of simplicity.
In step S1, the stacker crane 3 travels on the guide rail 21 in an empty state, and stops in front of the luggage storage shelf 13 with the cargo W to be delivered. In step S <b> 2, the lifting platform 27 is raised to the target height of the luggage storage shelf 13. In step S <b> 3, the slide fork 29 transfers the luggage W from the luggage storage shelf 13 to the lifting platform 27. In step S4, the lifting platform 27 descends and returns to the original position. In step S <b> 5, the stacker crane 3 travels on the guide rail 21 with the load W loaded thereon, and stops before the delivery station 19. In step S <b> 6, the slide fork 29 transfers the load W from the elevator 27 to the delivery station 19.

(6) Loading Operation The loading (shipping) operation in step S3 will be described in detail using the flowchart of FIG. In step S <b> 11, the luggage W is loaded from the luggage storage shelf 13. Specifically, the slide fork 29 protrudes downward from the load W, and the lift 27 rises from the state to lift the load W, and then the slide fork 29 retracts toward the lift 27 so that the load W Is pulled into the lifting platform 27.
In step S <b> 12, the deviation amount determination unit 71 determines whether a deviation has occurred based on the detection result from the angle sensor 37 connected to the deviation detection arm 35. If there is no deviation, the loading operation is completed normally and the next operation is started. For example, as shown in FIG. 8A, the case where there is no displacement is arranged at a position where the load W does not contact the displacement detection arm 35, and the center C of the pallet P in the left-right direction is the position of the lifting platform 27. This corresponds to the case where it coincides with the center in the horizontal direction.

  If there is a deviation, the process proceeds to step S13, and the deviation amount determination unit 71 determines whether the deviation amount is within an allowable range. For example, as shown in FIG. 9 (a), the case where there is a deviation means that a load W 'larger than the range in the left-right direction assumed in the lifting platform 27 is transferred and one deviation detection arm 35 rotates. It is in a state. If it is not within the allowable range, the process proceeds to step S17 to perform an abnormal stop. “Not within the allowable range” means, for example, a state in which a baggage rotates both of the shift detection arms 35. As described above, in the present embodiment, “there is a deviation but within an allowable range” means that the lateral width of the load W is shorter than the distance between the pair of shift detection arms 35, but the load W approaches one of the left and right directions. In this state, the detection arm is rotated.

In the case of the allowable range, the process proceeds to step S14, and the luggage W is returned to the luggage storage shelf 13. The operation of returning the load W to the load storage shelf 13 is the reverse of the operation of loading the load W from the load storage shelf 13. In step S15, the position compensation operation of the lifting platform 27 is performed. Specifically, the traveling carriage 23 moves by a compensation amount Z (1/2 of the deviation amount) toward the luggage deviation side and stops. Subsequently, in step S16, the luggage W ′ is loaded from the luggage storage shelf 13 in the same manner as in step S11. Then, as shown in FIG. 9 (b), the center in the left-right direction of the load W ′ coincides with the center in the left-right direction of the lifting platform 27. Note that the center C1 in the left-right direction of the pallet P is shifted from the center in the left-right direction of the lifting platform 27 by the compensation amount Z to the opposite side.
Summarizing the above, the allowable amount of luggage is increased by distributing the increase in the load appearance of the luggage to the left and right within the effective dimensions of the lifting platform. As described above, the increase in the allowable amount can reduce the load form recognized as abnormal, and as a result, stable operation is possible.

(7) Unloading operation The loading operation in step S3 in FIG. 6 will be described in detail with reference to the flowchart in FIG. Here, it is assumed that the stacker crane 3 is stopped at a regular position with respect to the delivery station 19. At the regular position, the center in the left-right direction of the stacker crane 3 and the center in the left-right direction of the exit station 19 coincide.
In step S21, it is determined whether or not the deviation amount determination unit 71 has performed position compensation at the time of loading the package. When the position compensation has not been performed (in the case of the luggage W), the process proceeds to step S23, and the luggage W is lowered to the delivery station 19 as it is. In this case, as shown in FIG. 8B, the center C in the left-right direction of the pallet P coincides with the center in the left-right direction of the delivery station 19.

  If position compensation has been performed (in the case of the baggage W ′), the process proceeds to step S <b> 22 to perform position compensation of the lifting platform 27. Specifically, the traveling carriage 23 moves toward the opposite side of the luggage W 'from the displacement side by the compensation amount Z (1/2 of the displacement amount) and stops. Subsequently, in step S23, the load W 'is loaded from the load storage shelf 13. Then, as shown in FIG. 9C, the luggage W ′ is disposed at a position where it does not contact the guide member 47. As a result, the center C1 in the left-right direction of the pallet P coincides with the center in the left-right direction of the delivery station 19, that is, the pallet P is unloaded at a normal position.

  In step S13, the deviation amount determination unit 71 may be able to determine whether or not the luggage exceeds the maximum luggage size based on the deviation amount. In this case, the storage unit 73 stores a predetermined maximum dimension of the package. In this case, in step S5 described above, the travel control unit 53 controls the stacker crane 3 to travel at a speed lower than the normal speed. The stacker crane 3 can stably transport the load by traveling at a low speed when the load exceeds the maximum dimension.

(8) Advantages of the present invention The stacker crane 3 is a transport vehicle that can transfer the load W between the load storage rack 13 and the stations 17 and 19 and carries the load W while it is traveling. A carriage 23, a lifting platform 27, a slide fork 29, an angle sensor 37, and a control unit 51 are provided. The elevator 27 is mounted on the traveling carriage 23. The slide fork 29 can transfer the load W between the lifting platform 27 and the load storage rack 13 or the stations 17 and 19. The angle sensor 37 detects the shift amount of the luggage W transferred from the luggage storage shelf 13 to the lifting platform 27 in the traveling direction. When the deviation amount is within the allowable range, the control unit 51 transfers the load W to the slide fork 29 from the lift 27 to the load storage shelf 13, and then compensates the shift amount to the traveling carriage 23. Next, control is performed so that the load W is transferred from the load storage shelf 13 to the lifting platform 27 on the slide fork 29.

In the stacker crane 3, since the angle sensor 37 detects the amount of deviation of the load W in the traveling direction, it can be determined whether or not the amount of deviation is within an allowable range. Further, by moving the luggage W onto the lifting platform 27 after the traveling carriage 23 has traveled a compensation amount corresponding to the deviation amount, an abnormal stop does not occur even if there is a slight deviation of the luggage W.
In particular, in the stacker crane 3, the traveling carriage 23 is traveled by a compensation amount in order to place the load W at an appropriate position on the lifting platform 27, so that no special mechanism is required.

  The stacker crane 3 preferably further includes a storage unit 73 that stores the compensation amount. When the load of the load W is transferred to the delivery station 19 after the deviation of the load W is detected and further compensated, the control unit 51 travels based on the compensation amount stored in the travel carriage 23 after stopping at the normal position. Thus, compensation is made for the exit station 19, and the load W is then transferred from the elevator 27 to the exit station 19 on the slide fork 29.

In the stacker crane 3, when the load W is transferred to the delivery station 19, the stop position of the traveling carriage 23 is changed from the normal position by the compensation amount. Thereby, the center of the pallet P on which the luggage W is placed can be placed in alignment with the center of the delivery station 19.
The loader transfer method of the stacker crane 3 of the present invention includes the following steps.
Step of transferring the load W from the load storage shelf 13 to the lifting platform 27 on the slide fork 29 (step S11 in FIG. 6)
◎ Step of detecting the shift amount of the load W placed on the lifting platform 27 in the traveling direction (step S12 in FIG. 6)
Step for determining whether or not the deviation amount is within the allowable range (step S13 in FIG. 6)
If the amount of deviation is within the allowable range, the load W is transferred from the lifting platform 27 to the luggage storage shelf 13 on the slide fork 29 (step S14 in FIG. 6), and then the amount of deviation is compensated for the traveling carriage 23. (Step S15 in FIG. 6), and next, the load W is transferred from the load storage shelf 13 to the lifting platform 27 on the slide fork 29 (step S16 in FIG. 6). In the load transfer method, since the amount of shift of the load W in the traveling direction is detected, it can be determined whether or not the shift is within an allowable range. Furthermore, the slide fork 29 transfers the load W to the lifting platform 27 after the travel cart 23 travels the compensation amount corresponding to the shift amount, so that no abnormal stop occurs even if the load W is slightly shifted. .

(8) Other Embodiments Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention.
In the embodiment shown in FIG. 10, photoelectric sensors 81 to 86 each composed of a pair of light projecting elements and light receiving elements are arranged on both the left and right sides of the lifting platform 27 as the displacement detection sensors for the load W ″. The on / off of the photoelectric sensors 81 to 86 can detect the presence / absence and the amount of deviation of the luggage W ″ from side to side.
In the above embodiment, the stacker crane of an automatic warehouse is taken as an example of the transport vehicle, but the present invention can also be applied to other transport vehicles.

The transfer device for the stacker crane is not limited to a slide fork, and may be a robot hand, for example.
The package may be transported without being placed on the pallet.
In the said embodiment, although the control part was mounted in the stacker crane, all or one part of the control part may be contained in the external controller.

  In the above-described embodiment, various control units are expressed as functional blocks, but these may be realized as a software program for causing a computer to execute these functions.

  The present invention is widely applicable to transport vehicles such as stacker cranes in automatic warehouses.

The schematic plan view of the automatic warehouse where the position embodiment of this invention was employ | adopted. It is an II-II arrow line view of FIG. 1, and is a figure for demonstrating a rack and a stacker crane. It is a III-III arrow line view of FIG. 1, and is a figure for demonstrating a rack and a stacker crane. The functional block diagram of the control part of a stacker crane. The flowchart which shows the basic operation | movement of a stacker crane. The flowchart which shows the operation | movement which loads a load into a crane. The flowchart which shows the operation | movement which unloads a package to a delivery station. The schematic diagram which shows the relationship between a luggage | load, a lifting platform, and a delivery station when there is no deviation | shift of a luggage. The schematic diagram which shows the relationship between a luggage | load, an elevator stand, and a delivery station when there exists a shift | offset | difference of luggage. The schematic diagram which shows the sensor for detecting the deviation | shift amount of a load in other embodiment.

Explanation of symbols

1 Automatic Warehouse 2 Rack 3 Stacker Crane 5 Stacker Crane Passage 7 Front Strut 9 Rear Strut 11 Luggage Support Member 13 Luggage Storage Shelf (Luggage Placement Section)
15 Fork passing gap 17 Warehousing station (loading part)
19 Departure station (loading part)
21 Guide rail 23 Traveling carriage (traveling part)
25 Mast 27 Lifting platform (storage part)
29 Slide fork (transfer section)
31 Placement part 33 Wall part 35 Deviation detection arm (detection means)
37 Angle sensor (detection means)
41 base 43 side wall 45 loading platform 47 guide member 51 control unit 52 controller 53 travel control unit 55 lift control unit 57 transfer control unit 59 travel motor 61 rotary encoder 63 lift motor 65 rotary encoder 67 transfer motor 69 rotary encoder 71 Deviation amount determination unit 73 Storage unit

Claims (4)

It is a transport vehicle that can transfer a package to and from the package mounting unit, and mounts and transports the package,
A traveling section;
A storage unit mounted on the traveling unit;
A transfer unit capable of transferring the luggage to a storage unit;
Detecting means for detecting a shift amount in the traveling direction of the load transferred from the load placement portion to the storage portion;
Determination means for determining whether or not the deviation amount is within an allowable range that can be stored in the storage unit;
When the deviation amount is within an allowable range, the compensation amount is transferred so that the load is transferred from the storage portion to the load placement portion, and then the traveling portion is compensated for the load collapse amount. A control unit that controls to move and then transfer the load from the load storage unit to the storage unit on the transfer unit;
A transport vehicle equipped with. Further comprising means for storing a predetermined maximum dimension of the luggage;
The determination means also determines whether or not the maximum load size is exceeded by the deviation amount,
The conveyance vehicle according to claim 1, wherein the control unit controls the traveling unit to travel at a low speed when the maximum package size is exceeded. A storage unit for storing the compensation amount;
When the load is transferred to another load placement unit after the load deviation is detected and compensated for, the control unit causes the running unit to travel based on a stored compensation amount. The transport vehicle according to claim 1, wherein compensation is performed for another load placing unit, and then the load is transferred to the other load placing unit from the storage unit to the transfer unit. A load transfer method for a transport vehicle comprising: a travel unit; a storage unit mounted on the travel unit; and a transfer unit capable of transferring a load between the load storage unit and the storage unit. ,
Transferring the load from the load placement unit to the storage unit on the transfer unit;
Detecting a shift amount of the load placed in the storage unit in the traveling direction;
Determining whether the deviation amount is within an allowable range;
If the deviation amount is within an allowable range, the compensation amount is transferred so that the load is transferred from the storage portion to the load placement portion on the transfer portion and then the running portion is compensated for the deviation amount. Traveling, and then transferring the load to the storage unit from the load storage unit to the storage unit, and
Transfer method for transport vehicles equipped with

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