JP4609373B2 - RFID communication system and RFID communication method - Google Patents

Description

  The present invention relates to an RFID communication system that performs read / write communication between an RFID tag attached to an object and an antenna.

  There is a need for means for collectively obtaining and managing information on articles stacked on the floor or stand of a store or factory, or information on articles stacked on a cart or a cart passing through a production line.

  As the management means, RFID tags are attached to a plurality of articles, information on the RFID tags is read (read), and information on the articles is written (written) on the RFID tags with a reader / writer, thereby collectively managing Has been developed.

  In the above management method, even if a plurality of RFID tags are dispersed in a wide three-dimensional range and the antenna of each RFID tag faces a random direction, the plurality of RFID tags are collectively collected by antennas installed above the passage or the production line. It is necessary to read / write the RFID tag.

Therefore, techniques for communicating with an RFID tag using a plurality of RFID tags and reflectors have been developed (Patent Documents 1 to 4).
JP 2005-4532 A JP 2005-193030 A JP 2003-283365 A JP 2000-56830 A

  The technology disclosed in the above-mentioned patent document sets a transmission path for transmitting electromagnetic waves from an antenna toward an RFID tag by a combination of reflectors, and transmits the electromagnetic waves from the antenna along the transmission path to the RFID tag. This is a configuration for propagation.

Therefore, when the RFID tag is attached to the side of the article and the antenna of the RFID tag is oriented in a random direction, the transmission path for guiding the electromagnetic wave to the RFID tag from the direction orthogonal to the direction in which the RFID tag is conveyed is It is easy to secure with the technology disclosed in the literature, but when the antenna of the RFID tag is oriented in the direction of carrying the RFID tag, it is not possible to secure an electromagnetic wave transmission path with the technology of the patent literature. It was impossible.

In order to secure the transmission path in the conveyance direction by the technique of the patent document, it is necessary to temporarily stop the conveyance of the article and reflect the electromagnetic wave from the front position thereof toward the antenna of the RF ID tag by the reflection plate. In this method, since the conveyance of the article is temporarily stopped every time the ride ride is performed, it is considered that the conveyance of the article takes time and the work efficiency is lowered.

  An object of the present invention is to enable read / write communication between an RFID attached to a side surface of an object and facing a random direction and an antenna of a reader / writer without temporarily stopping the object to which the RFID tag is attached. An RFID communication system and an RFID communication method are provided.

  In order to achieve the above object, an RFID communication system according to the present invention is installed at a position for receiving an electromagnetic wave from an antenna that performs communication between an RFID tag attached to an object and a read / write, and an electromagnetic wave from the antenna. It has a reflector which reflects electromagnetic waves toward the RFID tag.

According to the present invention, an electromagnetic wave from an antenna that performs read / write communication with an RFID tag attached to an object is reflected toward the RFID tag by a rotating reflector, and between the antenna and the RFDI tag. Executes read / write communication.

  In this case, the RFID tag may be provided on the side of the path along which the RFID tag moves in accordance with the movement of the object, and may have a reflection plate that reflects the reflected wave from the reflection plate toward the RFID tag. It is. Moreover, the said reflecting plate may be arrange | positioned at the both sides of the said path | route.

  As described above, according to the present invention, by using one antenna, one rotating reflector, and a reflector fixed to the side of the conveyance path, a plurality of RFID tags are three-dimensional. Even when the antenna surfaces of the RFID tags are randomly distributed in a wide range, read / write communication can be reliably performed with all the RFID tags.

  Further, by rotating the reflecting plate, communication with the RFID tag can be performed cheaply and easily than a communication system that switches a plurality of antennas according to the position of a carriage passing through a passage or a production line.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
As shown in FIG. 1, a carriage 8 is arranged in a conveyance path 5 such as a store passage or a factory production line so as to be movable by automatic control or human power. In FIG. 1, the carriage 8 moves in the X direction from the left side to the right side of the figure. The carriage 8 may reciprocate on the conveyance path 5.

  On the carriage 8, a plurality of articles 13 as objects are stacked three-dimensionally. One or a plurality of RFID tags 3 are attached to the side surfaces of the plurality of articles 13, and the RFID tags 3 are Three-dimensionally stacked on the carriage 8, the antenna surface of each RFID tag 3 (hereinafter referred to as an RFID tag surface) faces a random direction. Note that one large article 13 may be stacked on the carriage 8 and one or more RFID tags 3 may be attached to the side surface of the one article 13.

  In Embodiment 1 of the present invention shown in FIG. 1, an area 50 for performing read / write communication between the RFID tag 3 and the antenna 21 is set in the middle of the transport path 5. In the first embodiment of the present invention, no equipment for performing the read / write communication is installed in the direction in which the carriage 8 travels along the conveyance path 5 in the region 50, and the article 13 is mounted. The carriage 8 can freely move on the conveyance path 5 in the region 50.

  In the first embodiment of the present invention shown in FIG. 1 and FIG. 2, when the carriage 8 moves on the conveyance path 5 in the region 50, the antenna of the RFID tag 3 is attached to the side surface of the article 13 in a random direction. Even when it is facing, read / write communication is enabled between the RFID tag 3 and the antenna 2.

  Specifically, in the first embodiment of the present invention shown in FIGS. 1 and 2, the one antenna 21 is located above the region 50 and moves the carriage 8 on which the article 13 is mounted. The antenna fixture 31 is supported and installed at a height that does not interfere with the antenna. The antenna 21 is attached to the antenna fixture 31 so as to radiate the electromagnetic wave 6 upward. The antenna 21 is installed at a position almost directly above the carriage 8 traveling on the conveyance path 5.

  A motor 30 is installed at a position higher than the height of the antenna 21, for example, the ceiling 32, and its motor shaft 29 is directed vertically, and a first reflector 28 is attached to the lower end of the motor shaft 29. Yes.

  In addition, the second reflector 4 is disposed at a position on the side of the conveyance path 5 on which the carriage 8 travels and that does not interfere with travel of the carriage 3.

  Next, the relationship among the antenna 21, the first reflecting plate 28 at the upper position, and the second reflecting plate 4 at the side position will be described in detail. That is, the reflecting plate 28 is attached in an inclined posture with an elevation angle θ with respect to the motor shaft 29, and the motor shaft 29 is rotated around the motor shaft 29 as the rotation of the motor 28 with the angular rotation of the motor 28 is maintained. 4 is rotated over the first reflection area A, the second reflection area B, and the third reflection area C shown in FIG. FIG. 4 shows a trajectory in which the first reflecting plate 28 is rotated in the horizontal plane from the position overlooking the conveyance path 5.

The first reflecting plate 28 rotated in the range of the first reflecting region A is inclined in a solid line with one end 28a facing upward and the other end 28b facing downward in the -X · Z quadrant in FIG. Thus, the electromagnetic wave 6 from the antenna 21 is reflected as a reflected wave 7b on the RFID 3 attached to the front side surface 13a of the article 13 when the carriage 8 travels in the X direction.

The second reflection area B is a rotation area continuous to the first reflection area B, and the first reflection plate 28 rotated in the second reflection area B is in the Z · Y quadrant in FIG. Thus, the electromagnetic wave 6 from the antenna 21 is reflected as a reflected wave 7c toward the reflecting plate 4 disposed at a side position of the conveying path 5 with the inclined posture shown by a solid line with one end 28a facing upward and the other end 28b facing downward. reflect.

  The third reflection region C is a rotation region continuous with the second reflection region B, and the first reflection plate 28 rotated in the third reflection region C is in the quadrant of Z · X in FIG. In this case, the antenna 21 is attached to the RFID 3 attached to the rear side surface 13b of the article 13 when the carriage 8 travels in the X direction with the inclined posture shown by the dotted line with the one end 28a facing upward and the lower end 28b facing downward. The electromagnetic wave 6 is reflected as a reflected wave 7b.

The second reflectors 4 arranged at the lateral positions of the transport path 5 are arranged in a plurality of stages in the vertical direction, and the first reflector is changed to the second reflection position B shown in FIG. The reflected wave 7 d reflected by 28 is reflected in a substantially horizontal direction, and the reflected wave 7 d is radiated toward the RFID tag 3 attached to the side surface 13 c of the article 13. 1 and FIG. 2 are arranged in four stages, but the present invention is not limited to this, and one reflecting plate 4 may be arranged depending on the size of the reflecting surface. The number of reflection plates 4 shown in FIGS. 1 and 2 is not limited to the number of arrangements.

  The reflection surface of the first reflection plate 28 is formed as a parabola or a planar reflection surface. The electromagnetic wave from the antenna 21 is radiated upward, reflected by the first reflector 28, and the radiation direction of the electromagnetic wave is changed obliquely downward.

  The shape of the reflecting surface of the first reflecting plate 28 is a paraboloid of revolution, and the antenna 21 is installed at the focal point of the reflecting surface. The electromagnetic wave reflected by the first reflecting plate 28 has a sharp directivity without diffusing with parallel radiation characteristics, and the lower transport path 5 and the second reflecting plate with the rotation of the first reflecting plate 28. Radiated toward 4. The first reflecting plate 28 is fixed to the motor shaft 29 of the motor 30 fixed to the ceiling 32 with a depression angle θ, and is rotated by the motor 30 around the motor shaft 29 while maintaining the depression angle θ. In FIG. 1, the locus | trajectory which the 1st reflecting plate 28 rotates is shown with the broken line.

  The electromagnetic wave from the antenna 21 is radiated to the second reflecting plate 4 as the first reflecting plate 28 rotates. One or a plurality of second reflecting plates 4 are installed so as to reflect the reflected wave 7c from the first reflecting plate 28 and emit the reflected wave 7d in the horizontal or substantially horizontal direction. When the carriage 8 comes to a section passing the side of the second reflecting plate 4, the reflected wave 7 d is transmitted from the second reflecting plate 4 in the horizontal direction to the RFID tag 3 stacked three-dimensionally from the side. Radiated. Each second reflecting plate 4 reflects the electromagnetic wave 7c from the first reflecting plate 28 in the horizontal or substantially horizontal direction, and radiates the reflected wave 7d to the RFID tag 3 stacked three-dimensionally. The shape of the reflecting surface of the first reflecting plate 28 may be a flat surface. With the rotation of the first reflecting plate 28, the electromagnetic wave reflected by the planar reflecting surface of the first reflecting plate 28 is diffused as compared with the rotating paraboloid, and the lower transport path 5 and the second Radiated toward the reflector 4.

  The electromagnetic wave from the antenna 21 is generated by the article 13 in the traveling direction of the carriage 8 (X-axis traveling direction in FIG. 1) while the carriage 8 passes through the transport path 5 as the first reflecting plate 28 rotates. It radiates | emits toward all the surfaces of the front side surface 13a, the side surface 13c, and the back side surface 13b. The electromagnetic waves from the antenna 21 are also radiated from different directions to one or a plurality of RFID tags 3 facing a random direction attached to an article on the carriage 8 to form an effective communication path. 3 can communicate.

  As shown in FIG. 2, the number of second reflectors 4 varies depending on the width in the height direction of the second reflector 4 and the stacked height of the three-dimensionally stacked RFID tags 3. If the width of the reflection plate 4 is small, the number of the reflection plates 4 increases, and if the stacked height of the RFID tag 3 is large, the number of the second reflection plates 4 increases. However, when the width of the second reflector 4 is the same as the wavelength of the electromagnetic wave, or the same length as 3/4, 1/2 of the wavelength of the electromagnetic wave, etc., the resonance of the electromagnetic wave on the second reflector 4 Will occur, and the power of the reflected wave will drop. The width of the second reflector 4 needs to be set to a length equal to or longer than the wavelength of the electromagnetic wave.

  One or a plurality of second reflectors 4 are made of metal or the like on a wall of a store or factory, or a support provided on the side of a conveyance path 5 such as a store passage or a factory production line. It can be mounted almost vertically. The second reflector 4 is made of a square metal or a quadrangular synthetic resin coated with an electromagnetic wave reflector, and the shape of the reflecting surface is a flat surface, a secondary parabolic column surface, a cylindrical surface, an ellipsoidal surface, or the like. Become. When the shape of the reflecting surface of the reflecting plate 4 is a secondary parabolic column surface, a cylindrical surface, or an ellipsoidal surface, the reflected wave 7d from the reflecting plate 4 is not diffused compared to the planar reflecting plate 4. When the reflecting surface of the reflecting plate 4 is a secondary parabolic columnar surface, a cylindrical surface, or an ellipsoidal surface, the radiation characteristic that the reflected wave 7d is focused and becomes stronger toward the center of the three-dimensionally stacked RFID tag 3 is obtained. Show.

  The antenna 21 is connected to the reader / writer 11, and data obtained by read / write communication with the RFID tag 3 is sent to the computer terminal 15. The computer terminal 15 is connected to the server 17 via the network 16 and exchanges data with the server 17. The server 17 collects data obtained by the read / write communication with the RFID tag 3 from the computer terminal 15 and stores it in a database. The data is used for merchandise management in stores and manufacturing management in factories.

  As shown in FIG. 4, sensors 41 to 44 are installed along the conveyance path 5 in the region 50. These sensors 41 to 44 detect the carriage 8. The sensor 41 detects the carriage 8 that is about to travel into the region 50. The sensor 42 is installed at a position where the first reflecting plate 28 is switched from the first reflecting area A to the second reflecting area B. The sensor 43 is installed at a position where the first reflecting plate 28 is switched from the second reflecting region B to the third reflecting region C. The sensor 44 is installed at the detection position of the carriage 8 that exits the region 50.

  A control unit 46 for driving and controlling the motor 30 is configured using the CPU of the computer terminal 15. The control unit 46 is configured by the CPU of the computer terminal 15 reading and executing a control program stored in the internal memory. The control unit 46 calculates the current position of the carriage 8 in the region 50, and sets the direction of the first reflecting plate 28 to the first reflecting position A, the second reflecting position B, and the third reflecting position. A reflection plate directing control database 48 that switches to the reflection position C is provided.

  Based on the detection signal input from the sensors 41 to 44, the time information input from the timer 45, the speed information of the carriage 8 included in the current position database 47, etc. The current position of the cart 8 is determined. Based on the current position information of the cart 8 that has been determined, the control unit 46 includes information contained in the reflector directivity control database 48, and current attitude information of the first reflector 28 input from the drive controller 49. Based on the above, a command for rotating the first reflecting plate 28 to the first reflecting area A, the second reflecting area B, and the third reflecting area C is output to the drive controller 49. The drive control unit 49 controls the motor 30 based on a drive command output from the control unit 46, whereby the first reflection plate 28 is changed to the first reflection area A, the second reflection area B, Rotate to third reflection region C.

  Next, a case where RFID communication is performed between the RFID tag 3 and the antenna 2 using the RFID communication system according to the first embodiment of the present invention will be described.

  In the first embodiment, one antenna 21 and a first reflector 28 installed above the conveyance path 5 such as a passage or a production line, and one or a plurality of the first reflection plates 28 installed on the side of the conveyance path 5 are used. The two reflectors 4 perform read / write communication with a plurality of RFID tags 3 stacked three-dimensionally on the carriage 8.

  The RDID tag surfaces of the plurality of RFID tags 3 stacked three-dimensionally on the carriage 8 face a random direction. The received electromagnetic wave level of the RDID tag 3 changes in proportion to the effective reception area of the electromagnetic wave on the RDID tag surface viewed from the antenna 21, and when the electromagnetic wave from the antenna 21 enters the RDID tag surface perpendicularly, the electromagnetic wave on the RDID tag surface. The effective reception area is maximized, and the received electromagnetic wave level is maximized.

In FIG. 1, the carriage 8 moves along the conveyance path 5 along the traveling direction of the X axis. In step S <b> 1 of FIG. 5, the control unit 46 shown in FIG. 3 monitors whether the carriage 8 is within the area 50 of the conveyance path 5, that is, whether the read / write communication with the antenna 21 is possible. The control unit 46 continues the monitoring until the carriage 8 passes through the entrance in the region 50 (step S1; NO).

  When the sensor 41 detects the progress of the carriage 8 (step S1; YES), the control unit 46 uses the detection signal as a trigger based on the time information from the timer 45 and the stored information in the database 47 for the current position. It is detected that the carriage 8 has traveled to the entrance side of the region 50.

  Next, in step S <b> 2 of FIG. 5, the control unit 46 performs the first based on the information stored in the reflector directivity control database 48 and the information on the rotational position of the first reflector 28 from the drive control unit 48. It is determined that the reflecting plate 28 is rotated to the range of the first reflecting area A shown in FIG. When the reflection plate 28 input from the drive control unit 49 is rotated to the range of the first reflection area A shown in FIG. 4 (step S2; YES), the control unit 46 sends the reflection plate to the drive control unit 49. Command 28 to rotate as is.

  When the rotational position of the first reflector 28 input from the drive controller 49 is deviated from the range of the first reflection area A, the controller 46 sends the first reflector to the drive controller 49. A command for controlling the rotation of 28 is output. When receiving an instruction from the control unit 46, the drive control unit 49 drives the motor 30 to change the rotation range of the reflection plate 28 to the first reflection region A shown in FIG.

  Since the electromagnetic wave is radiated from the antenna 21 toward the first reflecting plate 28 based on the signal from the reader / writer 11, the first reflecting plate 28 rotating in the range of the first reflecting region A is While continuing the rotation, the electromagnetic wave 7a is reflected toward the front side surface 13a in the traveling direction of the article 13 on the carriage 8 traveling in the X-axis direction in FIG.

  Therefore, the RFID tag 3 attached to the front side surface 13a in the traveling direction of the carriage among the one or more RFID tags 3 attached to the one or more articles stacked on the carriage 8 is the first reflector 28. Therefore, communication with the antenna 21 is performed. Communication between the RFID tag 3 and the antenna 21 is performed while the electromagnetic wave 7 a radiated from the first reflecting plate 28 is radiated toward the RFID tag 3. The control unit 46 outputs a command to the drive control unit 49, and the drive control unit 49 determines the rotation speed of the first reflector 28 by the motor 30 from the start of communication between the antenna 21 and the RFID tag 3. A series of read / write communication until completion is controlled to a possible speed.

  Circularly polarized waves are used for electromagnetic waves used for communication from the antenna 21 to the RFID tag 3. When receiving an electromagnetic wave, the RFID tag 3 can receive both right-handed and left-handed circularly polarized waves. As an antenna of the RFID tag 3, a monopole antenna, a dipole antenna, a turn style antenna in which two sets of dipole antennas are combined at 90 degrees, a planar antenna, or the like is used, and these antennas are placed on the RFID tag surface of the RFID tag 3. Implemented. When the antenna of the RFID 3 is a monopole antenna or a dipole antenna, electromagnetic waves can be received from both the front and back surfaces and the side surface of the RFID tag 3. When the antenna of the RFID 3 is a planar antenna, electromagnetic waves can be received from both the front and back surfaces of the RFID tag 3.

  The electromagnetic wave level received by the RFID tag 3 includes the length of the path from the antenna 21 to the RFID tag 3, the radiation direction from the antenna 21 or the first reflector 28, and the antenna length of the RFID tag 3 or the antenna. The RFID tag 3 changes depending on the orientation of the RFID tag surface.

  When the RFID3 antenna is a monopole antenna or dipole antenna, the effective length of the RFID tag 3 viewed from the radiation direction is the effective reception length. When the antenna is a planar antenna, the effective area of the RFID tag surface viewed from the radial direction Then, when the radiation direction and the RFID tag surface are perpendicular to each other, the reception effective length or the reception effective area becomes maximum, and the reception electromagnetic wave level shows the maximum value.

  As shown in FIGS. 1 and 4, the carriage 8 further moves along the conveyance path 5 along the traveling direction of the X axis. When the carriage 8 moves from the first reflection area A to the second reflection area B, the sensor 42 detects the presence of the carriage 8.

  When the sensor 42 detects the carriage 8 that has traveled to the second reflection area B, the control unit 46 uses the detection signal as a trigger based on time information from the timer 45 and information stored in the database 47 for the current position. Then, it is detected that the carriage 8 has advanced within the range of the second reflection region B.

  Next, in step S <b> 3 of FIG. 5, the control unit 46 performs the first based on the information stored in the reflector orientation control database 48 and the information on the rotational position of the first reflector 28 from the drive controller 48. It is determined whether or not the rotational position of the reflection plate 28 has been switched to the range of the second reflection region B shown in FIG.

  When the reflection plate 28 input from the drive control unit 49 is rotated within the range of the second reflection region B shown in FIG. 4 (step S3; YES), the control unit 46 sends the reflection plate to the drive control unit 49. Command 28 to rotate as is.

  When the rotational position of the first reflector 28 input from the drive controller 49 is deviated from the range of the second reflection region B, the controller 46 sends the first reflector 28 to the drive controller 49. Outputs a command to control rotation. When receiving an instruction from the control unit 46, the drive control unit 49 drives the motor 30 to correct the rotation range of the reflection plate 28 to the range of the second reflection region B shown in FIG.

  When the carriage 8 advances to the side of the second reflecting plate 4, one or more RFID tags 3 attached to the side surface 13b of the one or more articles 13 stacked on the carriage 8 are shown in FIG. And it faces the second reflector 4 shown in FIG.

  Since the first reflecting plate 28 rotates in the second reflecting region B, the electromagnetic wave 6 from the antenna 21 is reflected toward the second reflecting plate 4 by the first reflecting plate 28. Therefore, the RFID tag 3 on the right side surface 13b in the traveling direction of the carriage 8 can communicate by receiving the electromagnetic wave 7d from the second reflecting plate 4, and thus performs communication between the antenna 21 and the read / write. In the communication, the electromagnetic wave 6 radiated from the antenna 21 is reflected by the first reflecting plate 28, the reflected wave 7c is reflected by the second reflecting plate 4, and the reflected wave 7d is radiated toward the RFID tag. Done while being.

  The control unit 46 outputs a command to the drive control unit 49, and the drive control unit 49 determines the rotation speed of the first reflector 28 by the motor 30 from the start of communication between the antenna 21 and the RFID tag 3. A series of read / write communication until completion is controlled to a possible speed.

  Further, in step S4 of FIG. 5, one or more RFID tags 3 attached to one or more articles stacked on the carriage 8 do not face the second reflector 4 in FIG. The RFID tag 3 on the left side 13d in the traveling direction of the carriage is a 180.degree. Rotation of a pedestal (not shown) of the carriage 8 supporting the article 13 by an automatic control mechanism (not shown) provided on the carriage 8 or by human power. The position of the tag 3 is changed to a position where the electromagnetic wave from the second reflecting plate 4 can be received.

  The control unit 46 detects that the detection signal is output from the sensor 42, the next sensor 43 does not detect the presence of the carriage 8, and the sensor 43 is within the set time based on the time information from the timer 45. On the condition that the presence of 8 is not detected, the drive control unit 49 is output that the first reflecting plate 28 is reversely rotated into the second reflecting region B. When the drive control unit 49 receives a command from the control unit 46, the drive control unit 49 reversely rotates the first reflecting plate 28 into the second reflection region B, and the RFID tag 3 attached to the left side surface 13 d of the article 13. And read / write communication with the antenna 21 are ensured.

  The control unit 46 outputs a command to the drive control unit 49 when receiving an output from the drive control unit 49 indicating that the first reflection plate 28 is reversely rotated in the second reflection region B. The drive control unit 49 rotates the first reflecting plate 28 to the end of the second reflecting region B based on a command from the control unit 46 to prepare for the next read / write.

  When the carriage 8 further moves along the traveling direction of the X axis and exits the side of the second reflecting plate 4, the sensor 43 detects the presence of the carriage 8 that has advanced into the third reflecting area C.

  When the sensor 43 detects the carriage 8 that has traveled to the third reflection area C, the control unit 46 uses the detection signal as a trigger based on time information from the timer 45 and information stored in the database 47 for the current position. Then, it is detected that the carriage 8 has advanced within the range of the third reflection region C.

  Next, in step S5 of FIG. 5, the control unit 46 performs the first based on the information stored in the reflection plate directing control database 48 and the information on the rotational position of the first reflection plate 28 from the drive control unit 48. It is determined whether or not the rotational position of the reflection plate 28 has been switched to the range of the third reflection region C shown in FIG.

  When the reflection plate 28 input from the drive control unit 49 is rotated within the range of the third reflection region C shown in FIG. 4 (step S5; YES), the control unit 46 sends the reflection plate to the drive control unit 49. Command 28 to rotate as is.

  When the rotational position of the first reflecting plate 28 input from the drive control unit 49 is deviated from the range of the third reflection region C, the control unit 46 sends the first reflecting plate 28 to the drive control unit 49. Outputs a command to control rotation. When the drive control unit 49 receives a command from the control unit 46, the drive control unit 49 drives the motor 30 to correct the rotation range of the reflection plate 28 to the range of the third reflection region C shown in FIG.

Of one or a plurality of RFID tags 3 attached to one or a plurality of articles stacked on the carriage 8, the reflected wave from the first reflector 18 on which the RFID tag 3 on the rear surface 13c of the carriage traveling direction rotates. 7b is received and communication becomes possible, so communication between the antenna 21 and the read / write is performed. The communication is performed while an electromagnetic wave radiated from the first reflecting plate 28 is radiated toward the RFID tag 3.

  The control unit 46 outputs a command to the drive control unit 49, and the drive control unit 49 determines the rotation speed of the first reflector 28 by the motor 30 from the start of communication between the antenna 21 and the RFID tag 3. A series of read / write communication until completion is controlled to a possible speed.

  When the carriage 8 further moves and exits the area 50, that is, the read / write communication possible range, the sensor 44 detects that the carriage 8 has exited the area 50 in step S6 of FIG. The control unit 46 completes communication between the RFID tag 3 and the antenna 21 using a detection signal from the sensor 44 as a trigger. Further, when the control unit 46 receives an output from the drive control unit 49 indicating that the first reflection plate 28 is rotated in the third reflection region C, it outputs a command to the drive control unit 49. The drive control unit 49 reversely rotates the first reflecting plate 28 to the start end of the first reflecting area A based on a command from the control unit 46 to prepare for the next read / write.

  As described above, according to the first embodiment of the present invention, by using one antenna, one rotating reflector, and a reflector fixed to the side of the conveyance path, Even when RFID tags are dispersed in a wide three-dimensional range and the antenna surface of each RFID tag faces a random direction, it is possible to reliably perform read / write communication with all RFID tags.

  Further, by rotating the reflecting plate, communication with the RFID tag can be performed cheaply and easily than a communication system that switches a plurality of antennas according to the position of a carriage passing through a passage or a production line.

(Embodiment 2)
FIG. 6 is a side view showing the second embodiment of the present invention, and FIG. 7 is a front view showing the second embodiment of the present invention.

  In the second embodiment of the present invention, one or a plurality of second reflecting plates 4 in the first embodiment are made into two sets, and the second reflecting plates 4 are installed on both sides in the carriage traveling direction. In FIG. 6, one set on one side (the second reflecting plate 4 on the left side in FIG. 4) is omitted.

  The two sets of second reflectors 4 are metal fittings on opposite wall surfaces of a shop or factory, or on pillars provided on opposite sides of the conveyance path 5 such as a shop passage or factory production line. It can be installed almost vertically using

  The second embodiment of the present invention has the same operation in the first reflection area A and the third reflection area C, but is different in that the article 13 on the carriage 8 is not rotated 180 ° in the second reflection area B. ing. This will be specifically described.

  When the sensor 42 detects the carriage 8 that has traveled to the second reflection area B, the control unit 46 uses the detection signal as a trigger based on time information from the timer 45 and information stored in the database 47 for the current position. Then, it is detected that the carriage 8 has advanced within the range of the second reflection region B.

  Next, in step S <b> 3 of FIG. 5, the control unit 46 performs the first based on the information stored in the reflector orientation control database 48 and the information on the rotational position of the first reflector 28 from the drive controller 48. It is determined whether or not the rotational position of the reflection plate 28 has been switched to the range of the second reflection region B shown in FIG.

  When the reflection plate 28 input from the drive control unit 49 is rotated within the range of the second reflection region B shown in FIG. 4 (step S3 in FIG. 5; YES), the control unit 46 controls the drive control unit 49 to The reflector 28 is instructed to rotate as it is.

  When the rotational position of the first reflector 28 input from the drive controller 49 is deviated from the range of the second reflection region B, the controller 46 sends the first reflector 28 to the drive controller 49. Outputs a command to control rotation. When receiving an instruction from the control unit 46, the drive control unit 49 drives the motor 30 to correct the rotation range of the reflection plate 28 to the range of the second reflection region B shown in FIG.

  When the carriage 8 advances to the side of the second reflecting plate 4, one or more RFID tags 3 attached to the side surface 13b of the one or more articles 13 stacked on the carriage 8 are shown in FIG. And it faces two sets of second reflecting plates 4 shown in FIG.

  Since the first reflecting plate 28 rotates in the second reflecting region B, the electromagnetic wave 6 from the antenna 21 is reflected by the first reflecting plate 28 toward the one second reflecting plate 4. Therefore, the RFID tag 3 on the right side surface 13b in the traveling direction of the carriage 8 can communicate by receiving the electromagnetic wave 7d from the second reflecting plate 4, and thus performs communication between the antenna 21 and the read / write. In the communication, the electromagnetic wave 6 radiated from the antenna 21 is reflected by the first reflecting plate 28, the reflected wave 7c is reflected by the second reflecting plate 4, and the reflected wave 7d is radiated toward the RFID tag. Done while being.

  The control unit 46 outputs a command to the drive control unit 49, and the drive control unit 49 determines the rotation speed of the first reflector 28 by the motor 30 from the start of communication between the antenna 21 and the RFID tag 3. A series of read / write communication until completion is controlled to a possible speed.

  Furthermore, among the one or more RFID tags 3 attached to one or more articles stacked on the carriage 8, the RFID tag 3 on the left side surface 13d of the carriage traveling direction is the other second reflector 4. Facing.

  Therefore, it is not necessary to rotate a pedestal (not shown) of the carriage 8 supporting the article 13 by 180 degrees.

  The control unit 46 detects that the detection signal is output from the sensor 42, the next sensor 43 does not detect the presence of the carriage 8, and the sensor 43 is within the set time based on the time information from the timer 45. On the condition that the presence of 8 is not detected, the drive control unit 49 outputs that the first reflecting plate 28 is normally rotated into the second reflecting region B. When the drive control unit 49 receives a command from the control unit 46, the drive control unit 49 rotates the first reflection plate 28 in the second reflection region B in the forward direction, and the RFID tag 3 attached to the left side surface 13d of the article 13. And read / write communication with the antenna 21 are ensured.

  The control unit 46 outputs a command to the drive control unit 49 when receiving an output from the drive control unit 49 indicating that the first reflection plate 28 is reversely rotated in the second reflection region B. The drive control unit 49 rotates the first reflecting plate 28 to the end of the second reflecting region B based on a command from the control unit 46 to prepare for the next read / write. The subsequent operation is the same as that of the first embodiment.

  As described above, according to the second embodiment of the present invention, one or a plurality of second reflecting plates 4 are additionally installed on the left side in the traveling direction of the carriage. When the carriage 8 moves on the conveyance path 5 such as a passage or a production line along the traveling direction of the X axis, and the carriage 8 advances to the side of the second reflecting plate 4, in the first embodiment, the second Since the radio wave does not reach the RFID tag 3 on the opposite surface when viewed from the reflector 4 of the above, the carriage has to be rotated 180 degrees. In the second embodiment, the second reflector 4 is also placed on the left side in the carriage traveling direction. Since it is installed, the RFID tag 3 on the left side in the traveling direction of the carriage can receive electromagnetic waves from the second reflecting plate 4 on the left side, and communication can be performed without rotating the carriage 8. is there.

  As described above, according to the present invention, the management system for articles, members, and devices stored in a factory, a warehouse, a distribution route, etc., RFID system that moves on a belt conveyor or a carriage, RFID, etc. The present invention can be applied to personal recognition systems in which tags are used, entrance / exit management systems, animal recognition systems in which RFID tags are used, animal management systems, and the like.

1 is a diagram showing an RFID communication system according to Embodiment 1 of the present invention, and is a side view seen from the Y-axis direction of FIG. FIG. 2 is a front view seen from the X-axis direction of FIG. It is a block diagram which shows the structure of the control part which concerns on embodiment of this invention. It is a figure explaining operation | movement of embodiment of this invention. It is a flowchart explaining operation | movement of embodiment of this invention. 6 is a diagram showing an RFID communication system according to Embodiment 2 of the present invention, and is a side view seen from the Y-axis direction of FIG. FIG. 7 is a front view seen from the X-axis direction of FIG.

Explanation of symbols

3 RFID tag 4 Second reflector 5 Carriage path 6 Electromagnetic waves 7a, 7b, 7c which are direct waves radiated from the antenna 8 Reflected wave from the reflector 8 Dolly 11 Reader / writer 15 Computer terminal 16 Network 17 Server 21 Antenna 28 First 1 reflector 30 motors 41 to 44 sensor 46 control unit 49 drive control unit

Claims (2)

An antenna that performs communication between the RFID tag attached to the object and the read / write;
The electromagnetic wave is installed at a position to receive the electromagnetic wave from the antenna, and rotated in a rotation range corresponding to the position of the object detected by the sensor, thereby changing the radiation direction of the electromagnetic wave obliquely downward to A first reflector that reflects toward the RFID tag;
A second reflector that is installed on the side of the path along which the RFID tag moves as the object moves, and reflects the reflected wave from the first reflector toward the RFID tag in a substantially horizontal direction. An RFID communication system comprising: The electromagnetic wave from the antenna that communicates with the RFID tag attached to the object and the read / write is changed obliquely downward in the radiation direction of the electromagnetic wave by the inclined first reflecting plate, and the object detected by the sensor Rotate the first reflector in a rotation range according to the position to reflect the electromagnetic wave toward the RFID tag of the object,
Furthermore, the reflected wave from the first reflecting plate is directed substantially horizontally toward the RFID tag by the second reflecting plate at a lateral position of the path along which the RFID tag moves as the object moves. Reflect
An RFID communication method comprising performing read / write communication between the antenna and the RFID tag.

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