JP7010256B2 - Information processing device, reader / writer, sidelobe passage determination method, control program - Google Patents

Description

The present invention relates to an information processing apparatus, a reader / writer, a sidelobe passage determination method, and a control program.

RFID (Radio Frequency Identification) technology is a technology that wirelessly communicates with an RF tag, reads information from the RF tag, and writes information to the RF tag, and is used in various industrial fields. One example is the application to goods on a production line. That is, an RF tag is attached to each article on the production line, and the progress of various production processes is monitored and managed based on the information stored in the RF tag.

In such an application example, the communication device and the RF tag communicate with each other when the RF tag moving on the production line passes through the communicable range in which the AC magnetic field radiated from the antenna coil of the communication device propagates. .. Therefore, it is necessary to arrange the RF tag so that the RF tag appropriately passes through the communicable range.

Patent Document 1 describes a technique for arranging an RF tag within a communicable range by measuring a distance from a communication device to an RF tag. Further, Patent Document 2 describes a technique of detecting the position of an RF tag and arranging the RF tag within a communicable range.

Japanese Unexamined Patent Publication No. 2006-324821 Japanese Patent Application Laid-Open No. 2003-223619

However, in the above-mentioned conventional technique, there is a problem that it cannot be determined whether the RF tag arranged within the communicable range is located in the main lobe or the side lobe of the AC magnetic field. The AC magnetic field radiated from the annular antenna coil of the communication device has a radiation magnetic field distribution such that two side lobes exist with the main lobe sandwiched in a cross section perpendicular to the plane including the annular antenna coil 11. However, the area of the side lobe is small. Therefore, communication in the side lobe is unstable. Therefore, in order to realize stable communication, it is necessary to place the RF tag in the main lobe.

One aspect of the present invention is to realize a technique capable of determining whether an RF tag has passed through a main lobe or a side lobe.

In order to solve the above problems, the information processing apparatus according to one aspect of the present invention includes an acquisition unit that acquires time-series data of reception intensity in an RF tag that moves across the main lobe of a reader / writer, and the reception unit. A determination unit for determining whether or not the RF tag has passed through the side lobe of the reader / writer based on the change in intensity is provided.

According to the above configuration, it can be determined whether or not the RF tag has passed through the side lobe of the reader / writer.

In one embodiment, the determination unit determines that the RF tag has passed through the side lobe when the reception intensity of the RF tag changes from decreasing to increasing.

According to the above configuration, it can be determined whether or not the RF tag has passed through the side lobe of the reader / writer.

In one embodiment, a high frequency removing unit that removes a high frequency from the time series data of the receiving intensity is provided, and the determination unit has the RF tag passing through the side lobe due to the change in the receiving intensity from which the high frequency is removed. Judge whether or not.

According to the above configuration, it is possible to determine whether or not the RF tag has passed through the side lobe of the reader / writer based on the time series data from which noise has been removed.

In one embodiment, the determination unit determines whether or not the RF tag has passed through the side lobe from the change in the reception intensity of one RF tag corresponding to one tag ID.

According to the above configuration, for each of the plurality of RF tags, it is possible to determine whether or not the RF tag has passed through the side lobe of the reader / writer.

In one embodiment, the RF tag includes a communication power control unit that reduces the power supplied to the antenna coil of the reader / writer when it is determined that the RF tag has passed through the side lobe.

According to the above configuration, the side lobe can be reduced by reducing the radiation range of the AC magnetic field radiated from the antenna coil. The RF tag can be made to pass through the main lobe.

In order to solve the above problems, the reader / writer according to one aspect of the present invention includes any of the information processing devices and an antenna coil for communicating with the RF tag.

According to the above configuration, a reader / writer capable of determining whether or not the RF tag has passed through the side lobe of the reader / writer is realized.

In order to solve the above problems, the sidelobe passage determination method according to one aspect of the present invention includes an acquisition step of acquiring time-series data of reception intensity in an RF tag moving across the main lobe of a reader / writer. A determination step for determining whether or not the RF tag has passed through the side lobe of the reader / writer from the change in the reception intensity is included.

According to the above configuration, it can be determined whether or not the RF tag has passed through the side lobe of the reader / writer.

In order to solve the above problems, the control program according to one aspect of the present invention is a control program for operating a computer as any one of the information processing devices, and serves as the acquisition unit and the determination unit. Make your computer work.

According to the above configuration, it can be determined whether or not the RF tag has passed through the side lobe of the reader / writer.

The term "RF tag" as used herein generally refers to an information medium that reads and writes information stored in a built-in memory in a non-contact manner using an AC magnetic field. A reader / writer (tag communication device) is used when reading and writing RF tag information. As the RF tag, names such as "RFID tag", "electronic tag", "IC tag", and "wireless tag" may be used. Further, the RF tag in the present specification includes both a passive tag and an active tag, and also includes a non-contact IC card mainly carried by a human.

According to one aspect of the present invention, it is possible to determine whether the RF tag is located in the main lobe or the side lobe.

It is a block diagram which shows an example of the main part structure of the reader / writer including the information processing apparatus which concerns on one Embodiment of this invention. It is a perspective view which shows the example of the positional relationship between the reader / writer and the RF tag. It is a figure which shows the example of the radiated magnetic field distribution of the AC magnetic field radiated from the reader / writer, and the position where an RF tag passes. It is a timing chart which shows an example of the procedure of communication between a reader / writer and an RF tag. It is a figure which shows an example of the graph which shows the time-dependent change of the received voltage of the RF tag with respect to the reader / writer. It is a flowchart which shows an example of the processing flow in the information processing apparatus which concerns on one Embodiment of this invention. It is a block diagram which shows an example of the main part structure of the reader / writer including the information processing apparatus which concerns on the modification of this invention.

Hereinafter, an embodiment according to one aspect of the present invention (hereinafter, also referred to as “the present embodiment”) will be described with reference to the drawings.

§1 Application example FIG. 1 is a block diagram showing an example of a main part configuration of a reader / writer 100 including an information processing apparatus 10 in the present embodiment. An example of a situation in which the present invention is applied will be described with reference to FIG. The reader / writer 100 includes an information processing device 10 according to the present embodiment and an antenna coil 11 for communicating with an RF tag. The antenna coil 11 may be another communication unit that radiates an electromagnetic wave or an AC magnetic field such as a resonance circuit, a modulation / demodulation circuit, or an RF circuit.

The reader / writer 100 operates the RF tag by wireless communication. This wireless communication is performed by the control unit 106 of the information processing device 10. In the present embodiment, the reader / writer 100 wirelessly communicates with an RF tag that moves with the movement of an article on a production line. An example of an operation performed by the reader / writer 100 on an RF tag is reading / writing information stored in a storage unit (not shown) of the RF tag.

Further, the reader / writer 100 acquires the time-series data of the reception intensity in the RF tag via the time-series data acquisition unit (acquisition unit) 103 of the information processing apparatus 10. The reader / writer 100 communicates with the RF tag 12 by an AC magnetic field radiated from the antenna coil 11. The AC magnetic field radiated from the antenna coil 11 has a radiated magnetic field distribution such that two side lobes are present across the main lobe in a cross section perpendicular to the plane including the annular antenna coil 11. The reader / writer 100 can communicate with the RF tag by moving the RF tag 12 across the main lobe.

The reader / writer 100 determines whether or not the RF tag has passed through the side lobe of the reader / writer 100 from the change in the reception strength obtained from the time series data of the reception strength acquired by the time series data acquisition unit 103. This determination is performed by the determination unit 104 of the information processing apparatus 10.

FIG. 2 is a perspective view showing an example of the positional relationship between the reader / writer 100 and the RF tag 12. The positional relationship between the reader / writer 100 and the RF tag 12 will be described with reference to FIG. The X direction is a horizontal direction and is a direction parallel to the surface including the annular antenna coil 11. The Y direction is a direction perpendicular to the surface including the annular antenna coil 11 (axial direction of the antenna coil 11). The reader / writer 100 communicates with the RF tag 12 when the RF tag 12 moving in the X direction passes within the communicable range of the reader / writer 100.

The communicable range of the reader / writer 100 is a range in which electric power for activating the RF tag 12 can be obtained by an AC magnetic field radiated from the antenna coil 11. The maximum value of the communicable range of the reader / writer 100 in the Y direction is, for example, about 90 cm. Therefore, by moving the RF tag 12 at a position within 90 cm in the Y direction with the reader / writer 100, the reader / writer 100 communicates with the RF tag 12.

FIG. 3 is a diagram showing an example of the radiation magnetic field distribution of the AC magnetic field radiated from the reader / writer 100 and the position where the RF tag 12 passes. The horizontal axis indicates the position in the X direction, and the vertical axis indicates the position in the Y direction. The shaded area in FIG. 3 indicates the communicable range (main lobe and side lobe). With reference to FIG. 3, the radiation magnetic field distribution of the AC magnetic field radiated from the reader / writer 100 and the position through which the RF tag 12 passes will be described. If the distance between the RF tag 12 and the reader / writer 100 in the Y direction is large (for example, about 40 cm), the RF tag 12 moving in the X direction passes only through the main lobe and has no side lobes in its movement path. ..

On the other hand, when the distance between the RF tag 12 and the reader / writer 100 in the Y direction is short (for example, about 15 cm), the RF tag 12 moving in the X direction also passes through the side lobe. When the RF tag 12 passes through the range including the side lobe, the communication is interrupted while the RF tag 12 passes through the break in the communicable range existing at the boundary between the side lobe and the main lobe. Since the sidelobe is narrow, communication errors can occur if communication is not completed while passing through the sidelobe. Further, if the passing position is slightly shifted in the Y direction, the communicable time becomes shorter. Therefore, in order to realize stable communication, it is preferable that the RF tag 12 passes only through the main lobe.

The information processing apparatus 10 determines whether or not the RF tag 12 has passed through the side lobe of the reader / writer 100 from the change in the reception intensity obtained from the time-series data of the reception intensity of the RF tag 12. Then, by adjusting the communication environment based on the determination result, stable communication between the RF tag 12 and the reader / writer 100 can be realized.

§2 Configuration example [Hardware configuration example of information processing device]
An example of the hardware configuration of the information processing apparatus according to the present embodiment will be described with reference to FIG. In the example of FIG. 1, the information processing apparatus 10 according to the present embodiment includes a modulation / demodulation unit 101 and a control unit 106.

The modulation / demodulation unit 101 communicates with the RF tag 12 by an AC magnetic field radiated from the antenna coil 11. The modulation / demodulation unit 101 modulates the transmission data received from the communication control unit 102 (described later) into a transmission signal to the RF tag 12. Further, the modulation / demodulation unit 101 demodulates the received signal transmitted from the RF tag 12 and received by the antenna coil 11 into received data and sends it to the communication control unit 102.

The control unit 106 comprehensively controls the processing executed by the information processing apparatus 10. The control unit 106 is configured by, for example, a computer. The processing performed by the control unit 106 is controlled, for example, by causing a computer to execute a control program. This program may be in the form of (i) reading and using what is recorded on removable media (CD-ROM, etc.), or (ii) reading and using what is installed in a hard disk, etc. Alternatively, (iii) the program may be downloaded via an external I / F, installed on a hard disk or the like, and executed.

The functional blocks included in the control unit 106 will be described later in the item of software configuration example.

[Software configuration example of information processing device]
The control unit 106 includes a communication control unit 102, a time series data acquisition unit 103, a determination unit 104, and a communication power control unit 105.

The communication control unit 102 is a functional block for exchanging information with the modulation / demodulation unit 101. The communication control unit 102 controls the communication process between the reader / writer 100 and the RF tag 12 via the modulation / demodulation unit 101. The communication control unit 102 sends the transmission data to be transmitted to the RF tag 12 to the modulation / demodulation unit 101. The communication control unit 102 receives the received data acquired from the RF tag 12 from the modulation / demodulation unit 101. The communication control unit 102 sends the received data acquired from the modulation / demodulation unit 101 to the time series data acquisition unit 103. The communication control unit 102 may associate the received data with the identification information (tag ID) of the RF tag 12 and send it to the time series data acquisition unit 103.

The transmission data sent by the communication control unit 102 includes a response request for the tag ID of the RF tag 12, a request for reading information written in the RF tag 12, a request for writing information newly written in the RF tag 12, and a request for writing information in the RF tag 12. Includes response requests for reception strength. The received data received by the communication control unit 102 includes the tag ID of the RF tag 12, the information read from the RF tag 12, the reception strength of the RF tag 12, and the like. The reception strength in the RF tag 12 is the strength of the AC magnetic field when the RF tag 12 receives, and is represented by the reception voltage.

FIG. 4 is a timing chart showing an example of a procedure for communication between the reader / writer (R / W) 100 and the RF tag 12. The data transmitted and received by the communication control unit 102 will be described with reference to FIG. As shown in FIG. 4, the communication control unit 102 of the reader / writer 100 transmits a response request for the tag ID to the RF tag 12. When the RF tag 12 is a passive type tag having no built-in battery, the communication control unit 102 transmits a response request for the tag ID after generating electric power to the RF tag 12 by electromagnetic induction of the antenna coil 11. .. Upon receiving the tag ID reply request, the RF tag 12 transmits the tag ID to the communication control unit 102.

The communication control unit 102 that has received the tag ID next transmits a response request for reading the information written in the RF tag 12 and a response request for the reception strength in the RF tag 12 to the RF tag 12. Upon receiving the response request for reading information and receiving strength, the RF tag 12 transmits the read information and receiving strength to the communication control unit 102.

The communication control unit 102 that has received the read information and the reception strength transmits the response request of the reception strength in the RF tag 12 to the RF tag 12. The RF tag 12 that has received the response request of the reception strength transmits the reception strength to the communication control unit 102. The communication control unit 102 that has received the reception strength further transmits a response request for the reception strength in the RF tag 12 to the RF tag 12. The communication control unit 102 repeats the reception strength response request until the RF tag 12 moves out of the communicable range and there is no reception strength response from the RF tag 12.

The time-series data acquisition unit 103 acquires time-series data of the reception intensity of the RF tag 12 that moves across the main lobe of the reader / writer 100. The time-series data acquisition unit 103 acquires time-series data of the reception strength of the RF tag 12 from the communication control unit 102. The time-series data acquisition unit 103 sends the acquired time-series data to the determination unit 104. The time-series data acquisition unit 103 may associate the time-series data with the tag ID of the RF tag 12 and send it to the determination unit 104.

FIG. 5 is a diagram showing an example of a graph showing a change over time in the received voltage of the RF tag 12 with respect to the reader / writer 100. The time-series data acquired by the time-series data acquisition unit 103 will be described with reference to FIG. As shown in FIGS. 3 and 5, the distribution of the change over time of the received voltage in the RF tag 12 generally corresponds to the radiated magnetic field distribution of the AC magnetic field radiated from the antenna coil 11.

As shown in FIG. 5, when the RF tag 12 passes only through the main lobe, the reception intensity is greatly increased and the reception intensity is decreased only once, and the reception intensity does not change from the decrease to the increase. On the other hand, when the RF tag 12 also passes through the side lobe, there is an inversion in which the reception intensity is small, increases and decreases, then greatly increases and decreases, and further decreases and decreases. As described above, when the RF tag 12 also passes through the side lobe, the reception intensity is reversed from the increase to the decrease a plurality of times, and therefore, the reception intensity may change from the decrease to the increase at least once.

The determination unit 104 determines whether or not the RF tag 12 has passed the side lobe based on the time series data received from the time series data acquisition unit 103. The determination in the determination unit 104 is performed by determining whether or not the reception intensity has changed from decreasing to increasing in the time series data. The determination unit 104 determines that the RF tag 12 has passed through the side lobe when the reception intensity changes from decrease to increase. Then, the determination unit 104 determines that the RF tag 12 has not passed through the side lobe when the reception intensity does not change from decrease to increase. The determination unit 104 sends the determination result to the communication power control unit 105. Further, the determination unit 104 may send the determination result to the display unit (not shown) or another device to notify the user.

The determination unit 104 may determine whether or not the RF tag 12 has passed through the side lobe from the change in the reception intensity of one RF tag 12 corresponding to one tag ID. The determination unit 104 acquires time-series data associated with one tag ID, and based on this, determines whether or not one RF tag 12 corresponding to one tag ID has passed the side lobe. Therefore, even when a plurality of RF tags flow one after another, it can be determined whether or not the RF tag has passed through the side lobe of the reader / writer 100 for each of them.

The communication power control unit 105 controls the power supplied to the antenna coil 11 of the reader / writer 100 based on the determination result received from the determination unit 104. By controlling the power supplied to the antenna coil 11, the radiation magnetic field distribution of the AC magnetic field radiated from the antenna coil 11 can be changed so that the RF tag 12 passes through the main lobe.

When it is determined that the RF tag 12 has passed through the side lobe, the communication power control unit 105 reduces the power supplied to the antenna coil 11 of the reader / writer 100. By supplying less power than the power previously supplied to the antenna coil 11, the spread of the radiated magnetic field distribution of the AC magnetic field shown in FIG. 3 in the Y direction becomes smaller than the previous time. By reducing the radiation range of the AC magnetic field, the side lobes can also be reduced. As a result, the RF tag 12 can be passed only through the main lobe without changing the position where the RF tag 12 passes.

§3 Operation example FIG. 6 is a flowchart showing an example of the processing flow in the information processing apparatus 10. An operation example in the information processing apparatus 10 will be described with reference to FIG. The processing procedure described below is only an example, and each processing may be changed to the extent possible. Further, with respect to the processing procedure described below, steps can be omitted, replaced or added as appropriate according to the embodiment.

In S61, the communication control unit 102 transmits a response request for reading information to the RF tag 12, and proceeds to S62.

In S62, the communication control unit 102 determines whether or not a response has been received from the RF tag 12. If it is determined in S62 that the communication control unit 102 has received the response (Yes), the process proceeds to S63. In this case, the RF tag 12 is within the communicable range of the reader / writer 100. If it is determined that the communication control unit 102 has not received the response (No), the process proceeds to S69 to output an error, returns to S61, and the process is repeated.

In S63, the communication control unit 102 transmits the response request of the reception strength in the RF tag 12 to the RF tag 12, and proceeds to S64.

In S64, the communication control unit 102 determines whether or not a response of reception strength has been received from the RF tag 12. If it is determined in S64 that the communication control unit 102 has received the response of the reception strength (Yes), the process returns to S63 and the process is repeated. If it is determined that the communication control unit 102 has not received the response of the reception strength (No), the process proceeds to S65. In this case, the RF tag 12 is out of the communicable range of the reader / writer 100. The steps S63 and S64 are repeated until the RF tag 12 goes out of the communicable range of the reader / writer 100.

In S65, the time-series data acquisition unit 103 acquires the time-series data of the reception strength of the RF tag 12 from the communication control unit 102 (acquisition step), and proceeds to S66.

In S66, the determination unit 104 determines whether or not the reception intensity has changed from decreasing to increasing based on the time-series data received from the time-series data acquisition unit 103 (determination step). If the determination unit 104 determines in S66 that the reception intensity has not changed from decreasing to increasing (No), the process proceeds to S67. If the determination unit 104 determines that the reception intensity has changed from decreasing to increasing (Yes), the process proceeds to S68.

In S67, the determination unit 104 sends a determination result that the RF tag 12 has not passed through the side lobe to the communication power control unit 105.

In S68, the determination unit 104 sends the determination result that the RF tag 12 has passed through the side lobe to the communication power control unit 105.

§4 Modification example A modification of the present invention will be described below. For convenience of explanation, the same reference numerals are given to the members having the same functions as the members described in the above-described embodiment, and the description thereof will not be repeated.

[4-1]
FIG. 7 is a block diagram showing an example of a main part configuration of a reader / writer 700 including an information processing apparatus 70 according to a modification of the present invention. The information processing apparatus 70 according to the modified example will be described with reference to FIG. 7. The information processing device 70 is different from the information processing device 10 shown in FIG. 1 in that it includes a high frequency removing unit 701.

The high frequency removing unit 701 removes high frequencies from the time series data of the reception intensity. The high frequency removing unit 701 receives the time series data of the reception intensity from the time series data acquisition unit 103, removes the high frequency and sends it to the determination unit 104. The high frequency removing unit 701 removes high frequencies from time-series data of reception intensity by a filter that suppresses the passage of signals in a high frequency band, such as a low-pass filter. As a result, noise can be removed from the time-series data of the reception intensity, and the determination unit 104 can more accurately determine whether or not the RF tag 12 has passed the side lobe.
[4-2]
In the processing example described in §3, in S64, the communication control unit 102 determines whether or not the response of the reception strength is received from the RF tag 12. On the other hand, in the determination in S64, if the response from the RF tag 12 is not received for a predetermined time, it is determined that the RF tag 12 is out of the communicable range of the reader / writer 100, and the response request of the reception strength is terminated. good.

[Example of implementation by software]
The control block of the information processing apparatus 10 (particularly, the communication control unit 102, the time series data acquisition unit 103, the determination unit 104, the communication power control unit 105, the control unit 106, and the high frequency removal unit 701) is an integrated circuit (IC chip). It may be realized by a logic circuit (hardware) formed in the above, or it may be realized by software.

In the latter case, the information processing apparatus 10 includes a computer that executes instructions of a program that is software that realizes each function. The computer includes, for example, one or more processors and a computer-readable recording medium that stores the program. Then, in the computer, the processor reads the program from the recording medium and executes the program, thereby achieving the object of the present invention. As the processor, for example, a CPU (Central Processing Unit) can be used. As the recording medium, a "non-temporary tangible medium", for example, a ROM (Read Only Memory) or the like, a tape, a disk, a card, a semiconductor memory, a programmable logic circuit, or the like can be used. Further, a RAM (Random Access Memory) for expanding the above program may be further provided. Further, the program may be supplied to the computer via any transmission medium (communication network, broadcast wave, etc.) capable of transmitting the program. It should be noted that one aspect of the present invention can also be realized in the form of a data signal embedded in a carrier wave, in which the above program is embodied by electronic transmission.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Is also included in the technical scope of the present invention.

10 Information processing device 11 Antenna coil 12 RF tag 100, 700 Reader / writer 103 Time-series data acquisition unit (acquisition unit)
104 Judgment unit 105 Communication power control unit 701 High frequency removal unit

Claims (7)

An acquisition unit that acquires time-series data of the reception intensity of an RF tag that moves across the main lobe of the reader / writer, and an acquisition unit.
A determination unit for determining whether or not the RF tag has passed through the side lobe of the reader / writer is provided from the change in the reception intensity, and the determination unit changes the reception intensity of the RF tag from decreasing to increasing. An information processing apparatus that determines that the RF tag has passed through the side lobe if this occurs at least once . It is equipped with a high frequency removal unit that removes high frequencies from the time series data of the reception intensity.
The information processing apparatus according to claim 1 , wherein the determination unit determines whether or not the RF tag has passed through the side lobe from the change in the reception intensity from which the high frequency is removed. The determination unit according to claim 1 or 2 , wherein the determination unit determines whether or not the RF tag has passed through the side lobe from the change in the reception intensity of the RF tag corresponding to the tag ID. Information processing device. The information according to any one of claims 1 to 3 , further comprising a communication power control unit that reduces the power supplied to the antenna coil of the reader / writer when it is determined that the RF tag has passed through the side lobe. Processing equipment. The information processing apparatus according to any one of claims 1 to 4 .
A reader / writer including an antenna coil for communicating with the RF tag. The acquisition step to acquire the time series data of the reception intensity in the RF tag that moves across the main lobe of the reader / writer, and
A determination step for determining whether or not the RF tag has passed through the side lobe of the reader / writer from the change in reception intensity is included .
The determination step is a sidelobe passage determination method in which it is determined that the RF tag has passed through the sidelobe when the reception intensity of the RF tag changes from decrease to increase at least once . A control program for operating a computer as the information processing apparatus according to any one of claims 1 to 4 , wherein the acquisition unit and the determination unit function as the computer.

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