JP2022071967A - Pallet management system - Google Patents

Abstract

[Problem] Manages the status of pallets without adding equipment or changing the configuration of the pallets. [Solution] A pallet management system according to the present invention comprises a wireless tag (10) attached to a pallet (2), a wireless tag reader (30) that receives a beacon signal transmitted by the wireless tag (10), and a pallet management device (40), the wireless tag (10) comprises wireless transmission means that transmits a beacon signal including identification information unique to the wireless tag (10) and beacon detection means that detects beacon signals transmitted by other stacked wireless tags, a first wireless tag transmits a beacon signal including detection information obtained by detecting a beacon signal transmitted by a second wireless tag by the beacon detection means to the wireless tag reader (30), the wireless tag reader (30) associates the identification information and detection information of the first wireless tag with each other and transmits them to the pallet management device (40), and the pallet management device (40) manages the status of the pallet (2) on which the first wireless tag is attached based on the identification information and detection information of the first wireless tag. [Selected Figure] Figure 1

Description

The present invention relates to a technique for managing the state of a pallet using a wireless tag installed on the pallet.

Generally, a pallet used for transporting or storing a cargo is stored in a warehouse in a state where the cargo is placed or a state in which the cargo is not placed. In order to use the pallets in the warehouse efficiently, it is necessary to manage the state of the pallets housed in the warehouse. In particular, it is important to know the number of empty pallets that are not loaded with luggage that can be used immediately.

Empty pallets without luggage are stored in a stacked state on the floor of the warehouse in order to make effective use of the space in the warehouse. In Patent Document 1, as a technique for managing such stacked pallets, the stacked pallets are photographed from a forklift camera, and a start bar provided on the front surface of the pallets included in the captured images is used. A technique for grasping the stacking state of pallets based on the vertical length of the stop bar has been proposed.

Japanese Unexamined Patent Publication No. 2015-084139

However, in grasping the state of palettes by images, equipment such as cameras for taking images of stacked palettes and software such as image processing for extracting the vertical length from the obtained images. Need to be added.

Also, if the front of the pallet in the warehouse contains a pallet that does not have a start bar or stop bar, it may not be possible to accurately grasp the state of the pallet. Changes may be required.

As described above, in the conventional technique, there is a problem that it is necessary to add equipment for managing the state of the pallet or change the configuration of the pallet.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a pallet management technique capable of managing the state of pallets without adding equipment or changing the pallet configuration. It is supposed to be.

In order to solve the above-mentioned problems, the pallet management system according to the present invention includes a wireless tag installed on the pallet, a wireless tag reader that receives a beacon signal transmitted by the wireless tag, and a pallet management device. In the pallet management system, the wireless tag is a wireless transmission means for transmitting a beacon signal including identification information unique to the wireless tag, and a beacon for detecting a beacon signal transmitted by another stacked wireless tag. The first wireless tag includes detection means, and the first wireless tag is configured to transmit the beacon signal including the detection information of detecting the beacon signal transmitted by the second wireless tag to the wireless tag reader by the beacon detecting means. The wireless tag reader associates the identification information of the first wireless tag with the detection information and transmits the detection information to the pallet management device, and the pallet management device transmits the identification information of the first wireless tag and the detection information. Based on the above, the state of the pallet on which the first wireless tag is installed is managed.

The pallet management device is an empty pallet on which the pallet on which the first wireless tag is installed is not loaded with luggage, based on the detection information associated with the identification information of the first wireless tag. May be determined.

Further, the beacon detecting means may be a passive wireless element that does not require electric power supplied from a power source.

Further, the pallet is configured by combining metal frame members, and the wireless tag is surrounded by the metal frame members and is arranged in a space without the metal frame members in the vertical direction of the pallet. Further, the radio tag may be arranged at the center of the pallet in a plan view.

Further, the pallet is provided with four strut portions at predetermined positions on the edge portion of the pallet in a plan view, and at least two strut portions are on the upper pallet and the lower side when the pallets are stacked. Alignment means for aligning the pallets may be provided.

Further, in the pallet, the at least two support columns are provided with the alignment means including protrusions or holes at the upper and lower portions thereof, and when the pallets are stacked, the protrusions and the holes are formed. May be aligned so that the upper pallet and the lower pallet are aligned.

According to the present invention, it is possible to provide a pallet management technique capable of managing the state of a pallet without adding equipment or changing the configuration of the pallet.

FIG. 1 is a configuration example of a pallet management system according to the first embodiment. FIG. 2 is an example of a functional block diagram of a wireless tag and a wireless tag reader according to the first embodiment. FIG. 3 is an example of the operation mode of the wireless tag in the first embodiment. FIG. 4 is an example of detection of a beacon signal of a wireless tag according to the first embodiment. FIG. 5 is an example of the state management data of the pallet in the first embodiment. FIG. 6 is an example of a sequence for explaining the pallet management method in the first embodiment. FIG. 7 is an example of a control flowchart of the pallet management method according to the first embodiment. FIG. 8A is a configuration example (top view) of the pallet in the second embodiment. FIG. 8B is a configuration example (A side view) of the pallet in the second embodiment. FIG. 8C is a configuration example (B side view) of the pallet in the second embodiment. FIG. 9A is a configuration example (A side view) of the pallet in the second embodiment. FIG. 9B is a configuration example (A side view) of the stacked pallets in the second embodiment. FIG. 9C is a configuration example (B side view) of the stacked pallets in the second embodiment. FIG. 10 is an example of the configuration of stacked pallets in the second embodiment. FIG. 11 is a verification result of the detection of the beacon signal in the second embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments described below.

<First Embodiment>
<System configuration>
FIG. 1 is a configuration example of a pallet management system according to the first embodiment. The pallet management system receives a wireless tag 10 installed on the pallet 2 used for transporting and storing luggage, and a beacon signal including unique identification information transmitted by the wireless tag, which is transported by the forklift 5 and housed in the warehouse 1. It is composed of a wireless tag reader 30 and a pallet management device 40 which is connected to the wireless tag reader 30 via a network 50 and manages the state of the pallet 2 in the warehouse 1. The wireless tag reader 30 may be configured to include a pallet management device 40.

The pallet 2 in the first embodiment is a resin pallet, and a wireless tag is housed in a space in the center of the pallet 2. For example, the wireless tag 10 may be housed in the central part of the storage box molded of resin and may be arranged in the space in the central part of the pallet 2. The present invention is applicable not only to pallets made of resin but also to pallets made of other materials, for example, pallets made of metal or the like.

The wireless tag 10 installed on the pallet 2 has a function of detecting a beacon signal transmitted by another wireless tag 10, and when the pallets 2 on which the wireless tag 10 is installed are stacked, the upper and lower pallets are stacked. It is possible to detect the presence of the beacon signal transmitted by the wireless tag 10 of the above, detect the existence of the pallet on the upper side or the lower side, and grasp that the pallets are stacked.

Here, since the beacon signal transmitted by the other stacked wireless tags is detected, it is desirable that the positions of the wireless tags in the vertical direction when stacked are aligned, but when stacking the pallets, it is desirable. Installation errors in the front-back direction or left-right direction between pallets are allowed to some extent. For example, in the case of a resin pallet having a thickness of about 150 mm, the distance between the wireless tags is close, so that an installation error in the wavelength range of the radio wave used by the wireless tag 10 is allowed. For example, when the frequency of the radio wave used by the wireless tag 10 is in the 920 MHz band (wavelength: 325 mm), it is possible to detect the beacon signal transmitted by another wireless tag even if there is an installation error of about 300 mm. be.

In addition, the accommodation position of the wireless tag in each pallet is preferably installed in the center of the pallet in a plan view, but it is limited to the center of each pallet as long as it can receive other beacon signals when stacked. It is not something that will be done.

Beacon signals of other radio tags in this radio tag are detected by a passive radio element. A passive wireless element is an element that operates by radio waves transmitted by an external device such as a wireless tag, and does not require electric power supplied from a power source such as a battery for its operation. This passive element is mounted on the active radio tag to activate the radio tag from the outside.

Since the reception gain of the passive radio element is small, it is not possible to detect the beacon signal transmitted by other radio tags installed apart from each other, but the radio tags are stacked with other radio tags and the radio tags are close to each other. In the state, the passive wireless element built in the wireless tag operates by using the radio wave of the beacon signal transmitted by the other wireless tag, and the presence of the other stacked wireless tags can be detected.

Each radio tag cannot determine if another radio tag is present on both the top and bottom, but by detecting the beacon signal from the other palette, it can at least either the top or the bottom. It is possible to grasp whether a wireless tag exists on one side.

The wireless tag 10 includes detection information indicating that the beacon signal of another wireless tag has been detected in the beacon signal transmitted to the wireless tag reader 30, so that the pallets on which the wireless tags are installed are stacked, that is, empty. It is possible to notify that it is in a state.

The wireless tag reader 30 has a function of collecting information of a plurality of wireless tags by receiving a beacon signal transmitted by the wireless tag and reading identification information (tag ID). The wireless tag reader 30 transmits the received wireless tag identification information and the detection information indicating that the beacon signal of another wireless tag is detected to the pallet management device 40 via the network 50.

The pallet management device 40 can manage the state of the pallet in the warehouse 1 based on the received identification information of the wireless tag and the detection information indicating that the beacon signal of another wireless tag is detected. If the beacon signal includes the detection information of the beacon signal of another wireless tag, it can be determined that the pallet is in a stacked state and is an empty pallet on which no luggage is placed.

As described above, according to the present embodiment, in the pallet management system including the wireless tag provided with the passive element and the wireless tag reader, the pallet is vacant without adding equipment or changing the pallet configuration. It becomes possible to provide a pallet management technology that can manage.

<Configuration of wireless tag and wireless tag reader>
FIG. 2 is an example of a functional block diagram of a wireless tag and a wireless tag reader according to the first embodiment. The wireless tags # A and #B are the wireless tags 10 of the stacked pallets, and the wireless tags # C are the wireless tags 10 installed on the pallets that are not stacked.

<Wireless tag>
The wireless tags # A, # B, and #C are active tags operated by the built-in battery 15, and are for detecting the vibration of the antenna 11, the wireless unit 12, and the wireless tag for transmitting a beacon signal including identification information. The vibration sensor 13 of the above, a passive radio element 14 for detecting a beacon signal transmitted by another radio tag, a central processing unit 16 for controlling each unit, and a memory 17 are included.

The passive wireless element 14 is an element that does not require electric power supplied from the battery 15 for its operation, and is used as a beacon detecting means for detecting a beacon signal transmitted by another stacked wireless tag.

The central processing unit 16 controls the operation mode of the wireless tag 10 according to the state of the vibration sensor 13, controls the transmission interval of the beacon signal, and uses the beacon signal to change the state of the wireless tag 10 to the wireless tag reader 30. Notice. Further, when the passive radio element 14 detects another beacon signal, the central processing unit 16 controls the information transmitted to the beacon signal so as to include the detection information of the beacon signal of the other radio tag.

For example, the payload of the beacon signal is provided with a flag for notifying the detection information of the beacon signal of another wireless tag, and by turning this flag ON / OFF, the presence or absence of detection of the beacon signal of the other wireless tag is determined. The wireless tag reader 30 may be notified.

<Wireless tag reader>
The wireless tag reader 30 is a device that receives a beacon signal transmitted by the wireless tag 10 and manages the state of the wireless tag 10. The wireless tag reader 30 includes an antenna 31 and a wireless unit 32 for receiving a beacon signal from the wireless tag 10, an I / F unit 33 for transmitting and receiving signals via the pallet management device 40 and the network 50, and a beacon signal. It is configured to include a central processing unit 34 and a memory 35 for performing transmission / reception control such as.

In the embodiment of the present invention, the transmission frequency and the transmission interval of the beacon signal in the wireless tag 10 are set for each predetermined operation mode, and the operation is based on the information from each sensor or the like provided in the wireless tag 10. The mode is changed, and the beacon signal is transmitted at the transmission frequency and transmission interval set for each operation mode. In the wireless tag 10, by setting the transmission interval of the beacon signal for each operation mode, it is possible to achieve both low power consumption of the wireless tag and maintenance of reliability of management.

<Wireless tag operation mode>
FIG. 3 is an example of the operation mode of the wireless tag according to the embodiment of the present invention. In FIG. 3, the wireless tag has a mode in which the pallet 2 is stationary in a warehouse or the like (“association mode”), a mode in which the pallet 2 is moving up and down (“vibration mode”), and a mode in which the pallet 2 is moved up and down for a long time. It has a mode in which it continues for a period of time and is moving (“moving mode”), and the transmission frequency and transmission interval of the beacon signal are set in each mode.

For example, in the association mode, the beacon signal is transmitted at predetermined intervals because it is stationary in the warehouse 1 (T1). The transmission cycle of the beacon in the association mode is set to be longer than that in the vibration mode in order to reduce power consumption.

Further, when the vertical movement of the pallet is detected, the pallet 2 is likely to move to another place by the forklift 5 or the like, so the mode shifts to the vibration mode in which the beacon signal is transmitted in a shorter cycle (T2). It enhances the reliability of pallet position management. Further, when the vibration of the pallet continues for a long time, the mode transitions to the movement mode having a longer transmission interval than the vibration mode (T3).

As described above, in the present embodiment, the transmission interval of the beacon signal is changed according to the state of the wireless tag 10, the reliability of pallet management is improved, and the power consumption is reduced. Further, the transmission frequency (F1-F3) of the beacon signal in each mode is also predetermined, and each radio tag 10 is configured to transmit the beacon signal at the transmission frequency and the transmission interval set for each operation mode. ing.

<Detection of beacon signal in wireless tag>
Next, the detection of the beacon signal in the wireless tag according to the embodiment of the present invention will be described. FIG. 4 is an example of detection of a beacon signal of a wireless tag according to the first embodiment.

The wireless tags # A, # B, and #C are wireless tags 10 installed on the pallet 2. As described with reference to FIG. 3, the radio tag transmits a beacon signal including identification information at a transmission frequency and a transmission interval determined for each operation mode. In FIG. 4, the wireless tags # A and #B are the wireless tags 10 of the stacked pallets 2, and the wireless tags # C are the wireless tags 10 installed on the pallets 2 that are not stacked.

Note that FIG. 4 illustrates a case where the wireless tags # A, # B, and #C are stationary and operating in the association mode, but the same applies to the case where the wireless tags # A, # B, and #C operate in the association mode.

For example, even when the stacked pallets 2 are moved together, each wireless tag can detect a beacon signal from the wireless tags installed on the other stacked pallets. In this case, by managing the state of the pallets together with the information of the vibration sensor, it is possible to collectively manage a plurality of stacked pallets as a group of pallets.

The wireless tag reader 30 receives the beacon signals transmitted by the wireless tags # A, # B, and #C, collects information on the status of the wireless tag using the beacon signals, and manages the status of the wireless tag. Can be done.

In the present embodiment, a flag for notifying the detection information of the beacon signal of another wireless tag is provided in the payload portion of the beacon signal, and by turning this flag ON / OFF, the beacon signal of the other wireless tag is signaled. Notifies the wireless tag reader 30 of the presence or absence of detection. For example, the beacon signal detected by the beacon signal transmitted by another radio tag transmitted from the radio tag #A is described as a beacon signal (A / ON), and the undetected beacon signal is described as a beacon signal (beacon signal (A / ON)). A / OFF).

The wireless tag #A transmits a beacon signal (A / OFF), and similarly, the wireless tags # B and #C transmit a beacon signal (B / OFF, C / OFF). At this point, since the wireless tag # A has not detected the beacon signal of the other wireless tag, the detection information of the beacon signal transmitted by the other wireless tag is "OFF" in the beacon signal to be transmitted.

When the pallet on which the radio tag # B is installed is stacked on the pallet on which the radio tag # A is installed, the passive radio element causes the radio tag # A to have another radio on the top or bottom of the radio tag # A. It is possible to detect that the tags have been stacked.

The wireless tag # A cannot specify that the other stacked wireless tags are the wireless tags # B, but detects that at least the other wireless tags are stacked by detecting the beacon signal. be able to. On the other hand, since the pallets on which the wireless tag #C is installed are not stacked, the wireless tag #A cannot detect the beacon signal of the wireless tag #C.

When the wireless tag #A detects the existence of a beacon signal transmitted by another wireless tag, the wireless tag #A outputs a beacon signal (A / ON) including the identification information of the wireless tag and the detection information of the beacon signal transmitted by the other wireless tag. It is transmitted to the wireless tag reader 30. Here, after transmitting the beacon signal (A / ON) including the detection information, the wireless tag #A resets the detection information of the other beacons and goes into the “OFF” state.

When the wireless tag reader 30 receives the beacon signal (A / ON) including the detection information of the beacon signal transmitted by another wireless tag from the wireless tag #A, the wireless tag reader 30 transmits the detected information to the pallet management device.

When the pallet on which the radio tag # B is installed is stacked on the pallet on which the radio tag # A is installed, the passive radio element causes the radio tag # B to have another radio on the top or bottom of the radio tag # B. It is possible to detect that the tags have been stacked.

When the wireless tag # B detects the existence of a beacon signal transmitted by another wireless tag, the wireless tag #B outputs a beacon signal (B / ON) including the identification information of the wireless tag and the detection information of the beacon signal transmitted by the other wireless tag. It is transmitted to the wireless tag reader 30. Here, after transmitting the beacon signal (B / ON) including the detection information, the wireless tag #B resets the detection information of the other beacons and goes into the “OFF” state.

When the wireless tag reader 30 receives the beacon signal (A / ON) including the detection information of the beacon signal transmitted by another wireless tag from the wireless tag #A, the wireless tag reader 30 transmits the detected information to the pallet management device. When the wireless tags # A and # B are no longer stacked, a beacon signal with the detection information set to "OFF" is transmitted. The wireless tag reader 30 may be configured to set the detection information of the wireless tag to "OFF" when the beacon signal having the detection information "OFF" is received a plurality of times.

Since the pallets on which the wireless tag # C is installed are not stacked, the wireless tag #C will continue to transmit the beacon signal (C / OFF) at predetermined intervals.

The wireless tag reader 30 transmits the identification information of the wireless tag and the detection information of the beacon of another wireless tag to the pallet management device 40. The pallet management device 40 can grasp the state of the pallet on which the wireless tag is mounted by managing the identification information in association with the detection information of the beacon of another wireless tag. If the detection information of the beacon signal of another wireless tag is included, it can be determined that the pallet is in a stacked state and is an empty pallet on which no luggage is placed.

<Palette status management data>
FIG. 5 is an example of pallet state management data according to the embodiment of the present invention. This state management data is recorded in the pallet management device 40. The pallet management device 40 manages the state of the pallet based on the identification information of the wireless tag and the detection information of the beacon signal of the other wireless tag.

The state management data of the pallet is composed of the pallet ID of the pallet, the wireless tag ID of the wireless tag installed on the pallet, the detection information of the beacon, and the information of the pallet. The pallet ID and the wireless tag ID are associated in advance, and the empty state of the pallet can be grasped by determining the stacking state for each pallet using the detection information of the beacon signal of the other wireless tag of the wireless tag. can do. The example of FIG. 5 shows the state of the pallet in the example of FIG. 4, and it is determined that the pallet on which the wireless tags # A and # B are installed is in an empty state in which no luggage is placed. ..

<Sequence>
FIG. 6 is an example of a sequence for explaining the pallet management method according to the first embodiment of the present invention. In the following description, the case where the beacon signal includes the detection signal of the beacon signal of another wireless tag is described as "ON", and the case where the beacon signal does not include the detection signal of the beacon signal of the other wireless tag is described as "OFF".

In the pallet management device, the pallet to be managed and the identification information of the wireless tag installed on the pallet are registered in advance. FIG. 6 illustrates a case where a pallet on which a wireless tag is installed is housed in a warehouse and the wireless tag operates in an association mode in which the wireless tag is stationary.

When the pallet on which the wireless tag #A is installed is moving, the wireless tag #A operates in the moving mode and transmits a beacon signal including the identification information (A) at the transmission interval in the moving mode. When the pallet on which the wireless tag #A is installed is housed in the warehouse, the operation mode of the wireless tag #A is changed (from movement to association), and the wireless tag #A transmits a beacon signal including the identification information (A). It transmits at a predetermined transmission interval specified in the association mode.

The wireless tag reader receives the beacon signal transmitted by the wireless tag # A. At this point, since the wireless tag #A has not detected the beacon signals of the other pallets, the detection information of the beacon signals of the other wireless tags is "OFF" in the beacon signals transmitted by the wireless tag #A. ..

The wireless tag reader transmits the received identification information and detection information (A / OFF) of the wireless tag #A to the pallet management device. The pallet management device can confirm that the pallet on which the wireless tag #A is installed is housed in the warehouse.

When the pallet on which the wireless tag # B is installed is moving, the wireless tag # B operates in the moving mode and transmits a beacon signal including the identification information (A) at the transmission interval in the moving mode. When the pallet on which the wireless tag # B is installed is housed in the warehouse, the operation mode of the wireless tag # B is changed (from movement to association), and the wireless tag # B transmits a beacon signal including the identification information (B). It transmits at a predetermined transmission interval specified in the association mode.

The wireless tag reader receives the beacon signal transmitted by the wireless tag # B. At this point, since the wireless tag # B has not detected the beacon signal of the other pallet, the detection information of the beacon signal of the other wireless tag is "OFF" in the beacon signal transmitted by the wireless tag # B. ..

The wireless tag reader transmits the received identification information and detection information (B / OFF) of the wireless tag # B to the pallet management device. The pallet management device can confirm that the pallet on which the wireless tag # B is installed is housed in the warehouse.

The wireless tag #A detects the beacon signal transmitted by the other wireless tag #B made by the built-in passive wireless element, and when it detects the presence of the other wireless tag #B, the identification information of the wireless tag #A and others. A beacon signal (A / ON) including the detection information of the beacon signal of the wireless tag B is transmitted to the wireless tag reader. Since the wireless tag #A has detected the beacon signal of the other palette, the detection information of the beacon signal of the other wireless tag is "ON" in the beacon signal transmitted by the wireless tag #A.

When the wireless tag reader 30 receives a beacon signal (A / ON) including detection information for detecting a beacon signal transmitted by another wireless tag from the wireless tag #A, the wireless tag reader 30 receives identification information of the received wireless tag # A and other information. The detection information of the beacon signal of the wireless tag is associated and transmitted to the pallet management device.

The pallet management device that received the identification information of the wireless tag #A and the detection information of the beacon of the other wireless tag updates the status management data of the wireless tag in FIG. 5, and changes the status of the pallet on which the wireless tag #A is installed. Change to "empty".

Similarly, the radio tag # B detects the beacon signal transmitted by the other radio tag # A made by the built-in passive radio element, and when it detects the presence of the other radio tag, the identification information of the radio tag # B is detected. And another beacon signal (B / ON) in which the detection information of the beacon signal of the wireless tag B is set to "ON" is transmitted to the wireless tag reader.

The pallet management device that received the identification information of the wireless tag #B and the detection information of the beacon of the other wireless tag updates the status management data of the wireless tag in FIG. 5 and sets the baggage status of the wireless tag #B to "empty". change.

By associating and managing the identification information of the wireless tag and the detection information of the beacon of another wireless tag, the state of the pallet on which the wireless tag is mounted can be grasped. If the detection information indicating that the beacon signal of another wireless tag is received is included, it can be determined that the pallet is in a stacked state and is an empty pallet on which no luggage is placed.

<Flow chart>
FIG. 7 is an example of a control flowchart in the wireless tag installed on the pallet according to the first embodiment of the present invention.

The pallet on which the wireless tag is installed moves (S1-1), and the wireless tag transmits a beacon signal at predetermined intervals defined in the movement mode (S1-2).

When the pallet on which the wireless tag is installed is housed in the warehouse (S1-3), the operation mode is changed from the movement mode to the association mode (S1-4). The wireless tag transmits a beacon signal at predetermined intervals defined in the association mode (S1-5).

When the wireless tag detects the beacon signal of another wireless tag (S1-6), the detection flag of the beacon signal of the other wireless tag becomes "ON" (S1-7), and the beacon signal sets the detection flag to "ON". Is transmitted (S1-8).

After that, while the pallet on which the wireless tag is installed is housed in the warehouse, transmission / reception of the beacon signal is repeated with the wireless tag reader. When the wireless tag no longer detects the beacon signal of the other wireless tag, a beacon signal with the detection flag of the beacon signal of the other wireless tag set to "OFF" is transmitted. Here, the wireless tag reader may be configured to set the detection information of the wireless tag to "OFF" when the beacon signal having the detection flag set to "OFF" is received a plurality of times.

<Second embodiment>
In the first embodiment, the case where the present invention is applied to a system using a resin pallet has been described, but in the second embodiment, a metal pallet in which a metal frame material is combined is used. The case where the present invention is applied to the system will be described.

<Palette configuration>
8A-8C is a configuration example of the pallet in the second embodiment. The pallet in the second embodiment is configured by combining metal frame members. 8A is a top view of the pallet 20, FIG. 8B is a side view of the pallet 20 in FIG. 8A, and FIG. 8C is a side view of the pallet 20 in FIG. 8A. In the configuration example of FIGS. 8A-8C, the wireless tag 10 is the central portion of the pallet 20 in a plan view, is surrounded by a rectangular frame 26 composed of a metal frame member, and has a metal frame in the vertical direction of the pallet 20. It is placed in a space without materials.

The wireless tag 10 may be arranged so that the metal frame material around the wireless tag 10 does not interfere with the radio waves transmitted by the wireless tag. For example, the wireless tag 10 is housed in the center of a storage box molded of resin, and then surrounded by a metal frame material formed on the pallet 20 so as to be arranged in a space without a metal frame material in the vertical direction. It may be configured.

In the present embodiment, the distance between the rectangular frame 26 and the wireless tag 10 is configured to be 1/3 or more of the wavelength of the radio wave used by the wireless tag 10. As a result, the antenna gain of the wireless tag 10 is secured, and the beacon transmitted by the wireless tag 10 can be reliably received by the wireless tag reader 30.

For example, when the frequency of the radio wave used by the wireless tag 10 is in the 920 MHz band (wavelength: 325 mm), the distance between the rectangular frame 26 and the wireless tag 10 may be 150 mm. It is only necessary to secure a distance between the wireless tag 10 and the surrounding metal frame material, and the shape of the metal frame material around the wireless tag 10 is not limited to a rectangle.

A strut portion 21 is erected on the edge portion which is the long side of the pallet 20. The strut portion 21 is composed of a base member 23 fixed to the pallet 20 and a strut member 22 installed above the base member. The strut portion 21 includes an alignment means for aligning the upper pallet and the lower pallet when the pallets are stacked. In the configuration example of FIGS. 8A-8C, a hole portion 24 is provided in the lower portion of the base member 23 as a positioning means. The hole portion 24 is configured so that the upper end portion of the support column member 22 can be fitted.

By fitting the upper end of the support column member 22 of the pallet 20 arranged below into the hole 24 of the base member 23 of the pallet 20 arranged above, a plurality of pallets are loaded in a state where the load is loaded on the pallet 20. 20 can be stacked up and down.

<Structure of stacked empty pallets>
9A-9C is a configuration example of the pallet in the second embodiment. FIG. 9A is a diagram showing a state in which the support column member 22 is bent in FIG. 8B. When the strut member 22 is bent, the height of protrusion from the pallet 20 is configured to be the same as the height of the base member 23.

Even when the support column member 22 is bent, the support column portion 21 includes an alignment means for aligning the upper pallet and the lower pallet when stacking the pallets. In the configuration example of FIG. 9A, a protrusion 25 is provided at the upper end of the base member 23. The protrusion 25 is configured to appear at the upper end of the base member 23 when the support member 22 is bent, and may be fitted with a hole 24 provided at the lower portion of the base member 23. It is configured to be possible.

9B and 9C are diagrams showing a state in which a plurality of empty pallets 20 on which no luggage is loaded are stacked. When the strut member 22 is bent, the protrusions 25 of the pallets 20 arranged below are fitted into the holes 24 of the pallets 20 arranged above, so that a plurality of empty pallets without luggage are loaded. The pallets 20 can be stacked one above the other in a state of being close to each other. Since the protrusion 25 of the support column 21 and the hole 24 are fitted to each other when the pallets are stacked, the case where the resin pallets of the first embodiment are stacked is compared with the case where the pallets are stacked. It is possible to realize a stacking configuration in which the upper and lower pallets 20 stacked are not displaced.

Here, the wireless tag 10 is a central portion of the pallet 20 in a plan view, is surrounded by a rectangular frame 26 composed of a metal frame material, and is in a space without a metal frame material in the vertical direction of the pallet 20. Since they are arranged, by realizing a stacking configuration in which the upper and lower pallets 20 do not shift in position, it is possible to accurately align the wireless tags 10 mounted on the pallets 20 in the vertical direction.

Here, regarding the position of the rectangular frame 26 in which the wireless tag 10 is arranged in each pallet, it is sufficient that another beacon signal can be received when the radio tags 10 are stacked, as in the first embodiment. Although not limited to the part, it is desirable to install it in the center part of the pallet in a plan view. Assuming that a plurality of pallets are arranged adjacent to each other in a plan view, by arranging the rectangular frame 26 in which the wireless tag 10 is arranged in the center of the pallet, the adjacent wireless tags are arranged at the farthest position. Therefore, it is possible to prevent erroneous detection of the beacons of the wireless tags 10 adjacent to the left and right.

Further, in the central portion of the stacked pallets 20, a space in the vertical direction is formed by the rectangular frame 26 composed of the metal frame material around the wireless tag 10. Since the distance between the rectangular frame 26 and the wireless tag 10 is secured so as to secure a distance of 1/3 or more of the frequency of the radio wave used by the wireless tag 10, due to the waveguide effect of this space. Even when the distance between the wireless tags 10 is relatively large, the beacon signal transmitted by the wireless tags installed on the other pallets 20 can be reliably detected.

Regarding the installation position of the wireless tag 10 in the rectangular frame 26, an installation error within a range in which the beacon signal can be detected is allowed due to the above-mentioned waveguide effect. For example, when the frequency of the radio wave used by the wireless tag 10 is in the 920 MHz band, another wireless tag transmits even if there is an installation error in the wavelength range of the radio wave used by the wireless tag 10, for example, about 300 mm. It is possible to detect the beacon signal.

The verification result of the beacon detection when the metal pallets are stacked will be described with reference to FIGS. 10 and 11. FIG. 10 is an example of the configuration of stacked pallets used for verification of beacon detection. In FIG. 10, it is composed of 11-stage metal pallets 20 (NO.1 to NO.11) on which the wireless tag 10 is installed, and the vertical distance between the pallets 20 is about 22 cm. In the case of the metal pallet of FIGS. 9A-9C, the distance between the pallets is larger than that of the resin pallet because of the bent support column member 22.

FIG. 11 is an example of the verification result of beacon detection in the configuration of FIG. FIG. 11 shows the measurement of the ratio of receiving the beacon signals from the wireless tags 10 installed on each pallet 20 multiple times in the association mode and including the detection information of the beacon signals of other wireless tags (tag detection ON). be. For example, NO. In one radio tag, in the reception of the beacon signal 12 times, the 12 beacons include the detection information of the beacon signal of the other radio tag.

According to the verification result of FIG. 11, it is shown that other beacon signals could be detected with a 100% probability in the stacking configuration of the pallets 20 stacked in 11 stages, and when the metal pallets are stacked. In, it was confirmed that other beacon signals could be detected with a high probability even when the distance between the pallets was larger than that of the resin pallet, and it was confirmed that the state of the pallet could be determined by this.
<Other embodiments>

In the above configuration example, the configuration in which the pallet 20 includes the four support columns 21 has been described as an example, but the number of the support columns 21 is not limited to four. Depending on the size and shape of the pallet, a larger number of struts than four may be provided.

In the above configuration example, the configuration in which the pallet 20 is provided with a protrusion on the upper portion and a hole portion in the lower portion of the four support columns 21 has been described as an example, but other configurations are provided as long as the upper and lower pallets can be aligned. May be adopted. For example, a hole portion may be provided in the upper portion and a protrusion portion in the lower portion of the support column portion 21, or a locking member configured so that the support column portion 21 does not slide in a plan view is provided instead of the hole portion. May be good.

Further, it is not necessary for the pallet 20 to provide protrusions and holes in all of the four support columns 21, for example, the protrusions and holes in two or three support columns 21 out of the four support columns 21. It may be configured to provide.

As described above, according to the embodiment of the present invention, it is possible to grasp the state of the pallet on which the wireless tag is mounted by managing the identification information of the wireless tag and the detection information of the beacon of another wireless tag in association with each other. can. If the beacon signal transmitted by the radio tag contains detection information indicating that the beacon signal of another radio tag has been received, the pallet is in a stacked state and is an empty pallet on which no luggage is placed. Can be determined to be.

According to the present embodiment, there is provided a pallet management technique capable of managing the state of a pallet without adding equipment for acquiring an image of the pallet or changing the configuration of the pallet to measure the height of the pallet. It becomes possible to do.

1 ... Warehouse, 2 ... Pallet, 5 ... Forklift, 10 ... Wireless tag, 11 ... Antenna, 12 ... Wireless unit, 13 ... Vibration sensor, 14 ... Passive wireless element, 15 ... Battery, 16 ... Central processing unit, 17 ... Memory, 20 ... pallet (made of metal), 21 ... strut part, 22 ... strut member, 23 ... base member, 24 ... hole part, 25 ... protrusion, 26 ... rectangular frame, 30 ... wireless tag reader, 31 ... antenna, 32 ... wireless unit, 33 ... I / F unit, 34 ... central processing unit, 35 ... memory, 40 ... pallet management device, 50 ... network.

Claims (7)

A pallet management system including a wireless tag installed on a pallet, a wireless tag reader that receives a beacon signal transmitted by the wireless tag, and a pallet management device.
The radio tag includes a radio transmission means for transmitting a beacon signal including identification information unique to the radio tag, and a beacon detection means for detecting a beacon signal transmitted by another stacked radio tag.
The first wireless tag is configured to transmit the beacon signal including the detection information of detecting the beacon signal transmitted by the second wireless tag to the wireless tag reader by the beacon detecting means.
The wireless tag reader associates the identification information of the first wireless tag with the detection information and transmits the detection information to the pallet management device.
The pallet management device is a pallet management system that manages the state of the pallet on which the first wireless tag is installed, based on the identification information of the first wireless tag and the detection information. The pallet management device is an empty pallet on which the pallet on which the first wireless tag is installed is not loaded with luggage, based on the detection information associated with the identification information of the first wireless tag. The pallet management system according to claim 1. The pallet management system according to claim 1 or 2, wherein the beacon detecting means is a passive wireless element that does not require electric power supplied from a power source. The pallet is constructed by combining metal frame members.
The pallet management system according to any one of claims 1 to 3, wherein the wireless tag is surrounded by the metal frame material and is arranged in a space without the metal frame material in the vertical direction of the pallet. .. The pallet management system according to claim 4, wherein the wireless tag is arranged at the center of the pallet in a plan view. The pallet is provided with at least four stanchions at predetermined positions on the edge of the pallet in a plan view, and at least two of the stanchions are on the upper pallet and the lower stanchion when the pallets are stacked. The pallet management system according to claim 4 or 5, further comprising an alignment means for aligning the pallets. The at least two strut portions are provided with the alignment means including protrusions or holes at the upper and lower portions thereof, and when the pallets are stacked, the protrusions and the holes are fitted to each other. The pallet management system according to claim 6, wherein the upper pallet and the lower pallet are aligned.

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