JP5385338B2 - Article ID reading apparatus, program and method - Google Patents

Description

  The present invention relates to an article, an article ID reader, a program, and a method.

  A smart shelf (hereinafter referred to as a shelf) using an RFID (Radio Frequency IDentification) is a product display shelf in which a reader / writer (hereinafter referred to as an RW Reader Writer) is installed. The smart shelf can read the tag ID of a product to which a tag (hereinafter referred to as an ID tag) having an ID capable of wireless communication called a tag is attached at a stretch. However, in a general RFID smart shelf, the RW reads only one frequency band. Of the two typical bands, in the UHF band, due to radio wave interference and antenna directivity, depending on the direction and position of the tag, a point where the tag cannot be read or overreading (incorrect reading) occurs. Although the influence of reflection is small in the 13.56 MHz band, the reading range is short because the reading distance is short, and this is a problem when the shelf is operated. Such a problem is a cause of stopping the operation of the smart shelf itself.

  In order to avoid this problem, interference materials for preventing radio wave interference and boosters for increasing the radio wave output have been studied, but sufficient results have not been obtained. Further, optimization of the antenna position has been studied, but this optimization takes a lot of man-hours. Further, the reading range may be changed by performing the above examination. In addition, in the above examination, there is a frequent problem that a range that can be read cannot be read. Further, if the installation environment of the smart shelf changes, the radio wave interference changes, and it is necessary to redo the above examination. Thus, in one frequency band, the reading distance, range, and protection of interference are limited, and the operation of the smart shelf itself is difficult.

  Patent Document 1 discloses generating a plurality of carrier waves having a plurality of frequencies, selecting a carrier having a frequency suitable for the environment in which the IC tag is attached, and communicating with the IC tag.

  Patent Document 2 allocates channels to be used so that both high and low systems do not interfere with each other based on the carrier sense value of a wireless channel in an environment where high and low power wireless IC tag reading systems coexist. A method is disclosed. As an example of carrier sense, this reference discloses measurement of RSSI (Received Signal Strength Received Signal Strength Indication).

  Patent Document 3 discloses that a moving means is provided on a shelf for storing a book with an RFID tag in order to avoid redundant reception of signals from an antenna.

JP 2005-209002 A JP 2008-192010 A JP 2010-227569 A

  The method of Patent Document 1 makes it possible to select an appropriate frequency for each RFID tag (hereinafter referred to as an IC tag), but the radio wave emitted toward the IC tag cannot physically reach this IC tag. When it falls, it cannot be improved.

  Although the method of Patent Document 2 can prevent high-power radio waves from interfering with the low-power wireless IC tag reading system, the radio waves directed to the IC tag are still physically blocked. It cannot be improved.

  Although the method of Patent Document 3 can improve the situation where the radio wave directed to the IC tag is physically interrupted by the movement of the shelf, the movement mechanism of the shelf and the number of steps are required.

  An object of the present invention is to solve the above-described problems and improve the detection accuracy of a signal transmitted from an ID tag.

  The article of the present invention is attached with a plurality of IC tags each having a resonance frequency in a different frequency band and storing the same ID.

  According to the present invention, the detection accuracy of an output signal from an IC tag can be improved.

FIG. 1 is a configuration diagram of a smart shelf to which the first embodiment of the present invention is applied. FIG. 2 is a block diagram of the first embodiment of the present invention. FIG. 3 is a diagram illustrating details of the switching unit 12 according to the first embodiment of this invention. FIG. 4 is a diagram illustrating an example of a product list according to the first embodiment of this invention. FIG. 5 is a flowchart showing the operation when the first embodiment of the present invention is applied to inventory survey. FIG. 6 is a diagram showing the frequency band names and the bands according to the first embodiment of the present invention. FIG. 7 is a configuration diagram of a smart shelf to which the second embodiment of the present invention is applied. FIG. 8 is a block diagram of the second embodiment of the present invention. FIG. 9 is a flowchart showing the operation when the second embodiment of the present invention is applied to inventory survey. FIG. 10 is a diagram showing an article according to the third embodiment of the present invention.

(First embodiment)
FIG. 1 is a configuration diagram when the first embodiment of the present invention is applied to a smart shelf.
The article 8 (the article 8 is also referred to as a product) has resonance frequencies in three different frequency bands (HF band: 13.11 to 14.01 MHz, UHF band: 860 to 960 MHz, UHF band: 1 to 3 GHz). IC tag H9, IC tag M10, and IC tag G11 are affixed. Further, the IDs of the articles 8 are commonly stored in the memories of the IC tag H9, the IC tag M10, and the IC tag G11. In the present embodiment, as shown in FIG. 6, the band names of the respective frequencies are called H, M, and G. The article 8 is placed on the product display shelf 3 on an antenna unit 7 (the antenna unit 7 is also referred to as an antenna substrate) on which an antenna H4, an antenna M5, and an antenna G6 corresponding to each resonance frequency are mounted. Yes. The antenna unit 7 is coupled to the RW 2 that transmits radio waves (electric signals) of each frequency via a coaxial cable. The RW 2 is wirelessly connected to the server 1 that stores the product list. IC tag H9, IC tag M10, and IC tag G11 are within the reach of electrical signals transmitted by RW2.

  FIG. 2 is a block diagram showing the configuration of FIG. In the server 1, the RSSI reference range and frequency set from the RSSI reference value for each frequency measured in advance under a predetermined condition in each IC tag are stored as a product list in association with the product ID. Yes. Here, the predetermined condition is determined by the type of IC tag to be used, the specification of the RW2, the use environment of the smart shelf, and the like, but this embodiment uses the following condition as an example. This condition is that each IC tag and RW2 are placed facing each other with an interval corresponding to the distance between the IC tag and the antenna corresponding to the resonance frequency, and the radio wave corresponding to each IC tag having an average intensity of RW2 is transmitted. When emitted, the RSSI value obtained from each IC tag is measured. Further, in the present embodiment, the RSSI reference value range shows a range having ± 10% as a boundary value centering on the average value (RSSI reference value) of the RSSI thus measured. This product list is referred to by the determination unit 26 of RW2. FIG. 4 is an example of a product list. In association with the product ID (A to D), the name of the frequency band in which the RSSI is measured, the RSSI reference value, and the RSSI reference range are shown. Note that RSSI may also be referred to as “signal strength”.

RW2 includes a receiving unit 21, a selecting unit 22, a transmitting unit 23, an RSSI measuring unit 24, a reading unit 25,
A determination unit 26 is included.

  The receiving unit 21 receives the ID signal transmitted from the IC tag H9, the IC tag M10, and the IC tag G11 by the receiving antenna.

  The transmitting unit 23 transmits electrical signals in the frequency bands H, M, and G and transmits the electrical signals to the antenna unit 7 via the switching unit 12. The selection of the frequency band is performed by a selection switch (not shown) set in the transmission unit 23. IC tag H9, IC tag M10, and IC tag G11 are within the reach of the electrical signal transmitted by transmitter 23.

  The RSSI measurement unit 24 measures the intensity of radio waves transmitted from the IC tag H9, the IC tag M10, and the IC tag G11, and outputs the RSSI value as a result to the determination unit 26.

  The reading unit 25 reads the product ID from the ID signal and outputs the product ID to the determination unit 26. The ID read by the reading unit 25 is also referred to as a reading ID.

  The selection unit 22 outputs a signal for selecting one of the frequencies H, M, and G to the transmission unit 23 and the switching unit 12, and outputs the selected frequency band name, H, M, and G to the determination unit 26.

  The determination unit 26 refers to all the rows of the product list stored in the server 1 and determines whether the combination of the ID acquired from each IC tag and the frequency band name acquired from the selection unit 22 exists in the product list. Determine whether. Here, the ID acquired from each IC tag may be referred to as a read ID. As a result, the determination unit 26 determines whether or not the RSSI value belongs to the RSSI standard range related to the same combination shown in the product list for the combination determined to exist in the product list. When the combination of ID and frequency is the same for all rows of the product list and the obtained RSSI value belongs to the RSSI standard range of the corresponding ID, the determination unit 26 determines that the inventory survey has been completed. When there is no combination of ID and frequency band name, the determination unit 26 writes the frequency band name together with the frequency band name to the unreadable list as the unreadable ID at that frequency and stores it in the server 1. In addition, even when there is a combination of ID and frequency band name, if the RSSI value does not belong to the RSSI standard range related to the same combination shown in the product list, the determination unit 26 uses the ID as an unreadable ID as a frequency. Write to the unreadable list along with the band name. After writing in the unreadable list, the determination unit 26 outputs a signal for selecting another frequency to the selection unit 22.

  The antenna unit 7 includes an antenna H4, an antenna M5, an antenna G6, and a switching unit 12. These antennas have resonance frequencies in frequency bands H, M, and G, respectively, and radiate electric signals from the transmitter 23 of the RW 2 as radio waves.

  When the IC tag H9, the IC tag M10, and the IC tag G11 receive the radiated radio wave, the IC tag H9, the IC tag M10, and the IC tag G11 each transmit an ID signal of the article 8 stored therein.

  As shown in detail in FIG. 3, the switching unit 12 is an aggregate of changeover switches that select an antenna having a resonance frequency at the frequency selected by the selection unit 22 and connect to the transmission unit 23. In addition, in FIG. 3, the state which connected the antenna H4 with the transmission part 23 and has terminated the other antenna is shown as an example. A dotted line indicates a signal for controlling the changeover switch transmitted from the selection unit 22. The switching unit 12 shuts off antennas other than the selected antenna from the transmission unit 23 by a terminating resistor.

FIG. 5 is a flowchart for explaining the operation when the present invention is applied to the inventory survey of goods. The determination unit 26 of the RW 2 reads a product list stored in the server 1 (S1).
Next, the selection unit 22 of the RW 2 sets the selection switch of the transmission unit 23 so that the transmission unit 23 transmits an electrical signal in the frequency band H. Further, the selection unit 22 outputs a signal to the switching unit 12, turns on the switch of the antenna H4, and terminates the switches of the antenna M5 and the antenna G6 with termination resistors. The receiving unit 21 receives the signal of the IC tag H9 by the receiving antenna. The reading unit 25 reads the ID of the article 8 from this signal, and the RSSI measuring unit 24 measures the RSSI value (S2).

  The determination unit 26 refers to the server 1, a combination of the product list stored in the server 1, the ID (product ID) of the product 8 acquired in S <b> 2 and the frequency band name H output from the selection unit 22, And its RSSI value.

  When the combination of the obtained ID and the frequency band name H matches the combination of the product ID and the frequency band name H of all the product lists, and the RSSI value belongs to the RSSI standard range of the product list, The determination unit 26 ends the determination process and creates a stock list (S3 YES). If there is a combination of ID and frequency band name H that are not obtained even though they exist in the product list, or there is an ID that is outside the RSSI reference range (S3 NO), the determination unit 26 displays the unreadable list. It is created and stored in the server 1. Subsequently, the determination unit 26 reads this unreadable list (S4). The data written in the unreadable list is an ID that is present in the product list but cannot be obtained, and an ID outside the RSSI standard range. In S4, the frequency band name H that could not be read may be recorded together.

  Next, the determination unit 26 of RW2 outputs the signal of the frequency band name M to the selection unit 22 so that the electrical signal of the frequency band M is transmitted from the transmission unit 23. The selection unit 22 of the RW 2 sets the selection switch of the transmission unit 22 so that the transmission unit 22 transmits an electrical signal in the frequency band M. Further, the selection unit 22 outputs a signal to the switching unit 12, turns on the switch of the antenna M5, and terminates the switches of the antenna H4 and the antenna G6 with termination resistors. The receiving unit 21 receives the signal from the IC tag M10, the reading unit 25 reads the product ID from this signal, and the RSSI measuring unit 24 measures the RSSI value (S5).

  The determination unit 26 refers to the server 1, and among the product list stored in the server 1, regarding the ID that matches the ID of the unreadable list, the product ID acquired in S <b> 5 and the frequency output from the selection unit 22. The combination with the band name M and its RSSI value are compared.

  In the product list, for all combinations of IDs and frequency band names M that match the product IDs in the unreadable list, the combination of the obtained ID and frequency band name M matches, and the RSSI value is the product When belonging to the RSSI standard range of the list, the determination unit 26 ends the determination process. Further, the determination unit 26 outputs the product list as an inventory list (S6 YES). If there is an ID that is not obtained even though it exists in the unreadable list (S6 NO), the determination unit 26 updates the unreadable list (S7). In this update, the determination unit 26 selects an ID whose RSSI value belongs to the RSSI standard range corresponding to the same ID of the frequency band name M in the product list from among the IDs obtained in S5 from the unreadable list. to erase. That is, in the unreadable list, IDs that could not be read in either frequency band H or frequency band M, and IDs whose RSSI values are outside the RSSI standard range in both frequency band H and frequency band M are recorded (S7). In S7, the frequency band names H and M that could not be read may be recorded together.

  Next, the determination unit 26 of RW2 outputs the signal of the frequency band name G to the selection unit 22 so that the electrical signal of the frequency band G is transmitted from the transmission unit 23. The selection unit 22 of the RW 2 sets the selection switch of the transmission unit 22 so that the transmission unit 22 transmits an electrical signal in the frequency band G. Further, the selection unit 22 outputs a signal to the switching unit 12, turns on the switch of the antenna G6, and terminates the switches of the antenna H4 and the antenna M5 with termination resistors. The receiving unit 21 receives the signal of the IC tag G11, the reading unit 25 reads the product ID from this signal, and the RSSI measuring unit 24 measures the RSSI value (S8).

  The determination unit 26 refers to the server 1, and among the product list stored in the server 1, regarding the ID that matches the ID of the unreadable list, the product ID acquired in S <b> 8 and the frequency output from the selection unit 22. The combination with the band name G and its RSSI value are compared.

  In the product list, for all combinations of IDs and frequency band names G that match the product IDs of the unreadable list, the combination of the obtained ID and frequency band name G matches, and the RSSI value is the product When belonging to the RSSI reference range of the list, the determination unit 26 ends the determination process. Further, the determination unit 26 outputs the product list as an inventory list (S9 YES). If there is an ID that is not obtained even though it exists in the unreadable list (NO in S9), the determination unit 26 updates the unreadable list (S10). In this update, the determination unit 26 selects an ID whose RSSI value belongs to the RSSI reference range corresponding to the same ID of the frequency band name G in the product list from among the IDs obtained in S8 from the unreadable list. to erase. That is, in the unreadable list, IDs that could not be read in frequency band H, frequency band M, or frequency band G, and IDs that have RSSI values outside the RSSI reference range in frequency band H, frequency band M, or frequency band G are stored. (S10). In S10, the frequency band names H, M, and G that could not be read may be recorded together.

  The determination unit 26 does not read the error message including an indication that the product with the ID stored in the unreadable list in S10 may be a missing item and that a reading error may occur in any frequency band. (S11).

  According to this embodiment, since a plurality of IC tags corresponding to different frequencies are attached to one article (product), the reading efficiency of the IC tag signal is improved.

  In the present embodiment, the server 1 and the RW 2 are connected wirelessly. However, the wireless connection is not necessarily required, and wiring connection may be used.

  The IC tag used in this embodiment may be a passive type or an active type.

  The determination unit 26 and the selection unit 22 in the present embodiment may be realized by hardware that executes a combination of logic circuits, or may be realized by an application program using computer software.

  In the present embodiment, three IC tags are affixed to one product. However, the number of IC tags is not necessarily three, and may be two. Further, the number of IC tags may be four or more.

  In the present embodiment, the transmitter 23 is configured to switch and transmit electrical signals in a plurality of frequency bands, but switching is not necessarily required. A frequency may be selected by simultaneously transmitting electrical signals in a plurality of frequency bands and switching the antenna.

In the present embodiment, the product list is stored in the server 1, but it is not always necessary to store in the server 1, and the product list may be stored in a storage unit such as a disk or a memory.
(Second Embodiment)
FIG. 7 is a configuration diagram when the second embodiment of the present invention is applied to a smart shelf. In this embodiment, a motor-controlled moving mechanism unit 31 is added to the configuration of the first embodiment, and the antenna position can be moved back and forth and left and right in order to obtain an optimum RSSI value. . When this configuration is adopted, reading of the IC tag is further facilitated. In FIG. 7, the merchandise display shelf 30 is fixed to the support column, whereas the antenna unit 27 positioned at the lower part of the merchandise display shelf 30 is mounted on the moving mechanism unit 31, and is connected to the merchandise display shelf 30. Can be moved. As the moving mechanism unit 31, an XY stage can be used. In FIG. 7, in order to explain mainly the function of moving the antenna position, the IC tag and the antenna are simplified to one each, but a plurality of ID tags are attached to the product, and a plurality of antennas are arranged. The configuration is the same as in the first embodiment. FIG. 8 is a block diagram showing the configuration of FIG. The difference from FIG. 2 is that the determination unit 26 is connected to a pulse motor 32 that drives the movement mechanism unit 31. Here, the moving mechanism unit 31 is composed of a movable stage that can move in two axial directions, and the antenna unit 27 mounted on the moving mechanism unit 31 is driven by a pulse motor 32, whereby the product display shelf 30. Is movable. The pulse motor 32 is driven by an output signal from the determination unit 26 of RW2. In the present embodiment, the X direction is the longitudinal direction of the antenna unit 27, and the Y direction is the depth direction of the antenna unit 27.

  FIG. 9 is a flowchart for explaining the operation when the present embodiment is applied to the inventory survey of products. The difference from FIG. 5 is that when the received ID does not match the product list, or when the RSSI value is outside the RSSI reference range (S23, S28, S33 NO), the determination unit 26 determines the RSSI value by the RSSI measurement unit 24. The pulse motor 32 is driven simultaneously with the measurement.

  The pulse motor 32 drives the moving mechanism unit 31 to move the antenna unit 27 in the direction in which the RSSI value falls within the RSSI standard range with respect to the merchandise display shelf 30 (S25, S30, S35). The position 27 is adjusted so as to be in the optimum range.

  Prior to driving the moving mechanism 31, the determining unit 26 confirms that the moving amount does not exceed the specified value (maximum moving amount) (S24, S29, S33). When the movement amount exceeds the maximum movement amount, the determination unit 26 considers that reading in that frequency band is impossible, and outputs a signal for selecting the next frequency band (NO in S25 and S30). When the maximum movement amount is exceeded in any frequency band, the determination unit 26 outputs an error message indicating a possibility of a missing item or a possibility of unreadable as a reading mismatch alert (S36).

  In S24 NO, S29 NO, and S34 NO, the drive amount of the pulse motor 32 may be recorded in the server 1, and the movement mechanism unit 31 may be returned to the state before the movement. Further, this driving amount may be recorded in the unreadable list.

In the above embodiment, a plurality of frequency bands are serially operated. However, when the RW 2 reads the product tag ID in order to shorten the processing time, the plurality of frequency bands may be read simultaneously.

In this embodiment, by adopting a configuration in which the position of the antenna unit can be adjusted, the reading efficiency of the ID tag signal is further improved more efficiently than in the first embodiment.
(Third embodiment)
FIG. 10 is a diagram showing the configuration of the third exemplary embodiment of the present invention. The present embodiment is an article 8 having a plurality of IC tags A13 and IC tags B14 each having a resonance frequency in a different frequency band and storing the same ID.

1 server 2 RW
3 Product display shelf 4 Antenna H
5 Antenna M
6 Antenna G
7 Antenna part 8 Article 9 IC tag H
10 IC tag M
11 IC tag G
12 switching part 13 IC tag A
14 IC tag B
DESCRIPTION OF SYMBOLS 21 Reception part 22 Selection part 23 Transmission part 24 RSSI measurement part 25 Reading part 26 Judgment part 27 Antenna part 30 Goods display shelf 31 Movement mechanism part 32 Pulse motor

Claims (6)

Receiving means for receiving signals transmitted from a plurality of IC tags attached to an article and having resonance frequencies in different frequency bands and storing the same ID ;
A transmission means having a frequency selection function for switching a transmission frequency band to one of the frequency bands, and transmitting an electrical signal in the transmission frequency band;
Storage means for storing a reference range of the signal strength in association with the frequency band and the ID;
Measuring means for measuring the intensity of the signal received by the receiving means;
Reading means for reading the signal of the ID transmitted by the IC tag as a reading ID;
When the transmission frequency band is a first frequency band including a resonance frequency of a first IC tag that is one of the IC tags, the reading ID read by the reading unit is equal to the ID and the ID Whether the intensity of the signal emitted by the first IC tag measured by the measurement means belongs to a reference range set in association with the ID and the first frequency band is referred to the storage means. If the determination is negative, the second frequency band includes a resonance frequency band of a second IC tag that is one of the IC tags and is different from the first IC tag. Determining means for switching the transmission frequency band of the transmission means to a frequency band,
ID reader for reading the ID of prior SL IC tag stores. The ID reader according to claim 1 , further comprising a moving unit that moves the antenna unit with respect to the ID tag so that the intensity of the signal measured by the measuring unit falls within the reference range. Receiving processing for receiving signals transmitted by a plurality of IC tags having resonance frequencies in different frequency bands, which are affixed to articles, and storing the same ID, at a receiving unit;
A transmission process of switching the transmission frequency band to any of the plurality of frequency bands, and transmitting an electrical signal of the transmission frequency band from a transmission unit;
A storage process for storing a reference range of the signal intensity in a storage unit in association with the frequency band and the ID;
A measurement process in which the measurement unit measures the intensity of the signal received by the reception unit;
A reading process of reading the ID signal transmitted by the IC tag as a reading ID;
When the transmission frequency band is a first frequency band including a resonance frequency of a first IC tag that is one of the IC tags, the reading ID read by the reading unit is equal to the ID and the ID Whether the intensity of the signal emitted by the first IC tag measured by the measurement unit belongs to a reference range set in association with the ID and the first frequency band is referred to the storage unit. If the determination is negative, the second frequency band includes a resonance frequency band of a second IC tag that is one of the IC tags and is different from the first IC tag. ID reading program reads the ID of the determination process for switching the transmission frequency band of the transmitter unit to the frequency band, causing a computer to execute, the previous SL IC tag stores. 4. The ID reading program according to claim 3, wherein the computer executes a moving process of moving the antenna unit with respect to the ID tag so that the intensity of a signal emitted from the first IC tag falls within the reference range. Receiving a signal transmitted by a plurality of IC tags attached to an article, each having a resonance frequency in a different frequency band and storing the same ID, at the receiving unit;
The transmission frequency band is switched to one of the plurality of frequency bands, and an electric signal of the transmission frequency band is transmitted from the transmission unit,
The reference range of the signal strength is stored in the storage unit in association with the frequency band and the ID,
Measure the strength of the signal received by the receiving unit in the measuring unit,
Read the ID signal transmitted by the IC tag as a read ID,
The transmission frequency band is the resonance frequency of the first IC tag in which the read ID is different from the ID or the intensity of the signal transmitted by the first IC tag is one of the IC tags. When the first frequency band is included, the reading ID read by the reading unit is equal to the ID, and the intensity of the signal emitted by the first IC tag measured by the measurement unit is the ID and the first frequency band. Whether or not it belongs to a reference range set in association with a frequency band is determined with reference to the storage unit. If the determination is negative, one of the IC tags in the frequency band is determined. determining by switching the transmission frequency band of the transmission unit in a second frequency band including the resonance frequency band of the different second IC tag from the first IC tag there, the previous SL IC tag stores ID reading to read ID Law. 6. The ID reading method according to claim 5, wherein the antenna unit is moved with respect to the ID tag so that the intensity of a signal emitted from the first IC tag falls within the reference range.

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