JP2007206793A - Reading system and reading method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely attain accurate and high-speed reading of a position of a mobile body. <P>SOLUTION: When a reading system for performing reading of a plurality of different identifiers which are attached to a measuring object by a wireless reader is constituted, assignment of time slots is performed using part or all of information owned by the respective identifiers, and identifiers preliminarily selected so that information regulating the assignment of the identifiers is entirely differed in one reading opportunity are attached to a mobile body of an identification target. According to this, the reading system can be constituted without using a unique anti-collision technique for attaining high-speed reading. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reading system and a reading method, and more particularly to a technology for grasping and specifying the position of a moving object or a person. For example, in product assembly in a factory, a person delivers a work in progress according to the progress of work. The present invention relates to a technique suitable for use at high speed and surely grasping the position of a carriage on which work-in-process items used in a cell production system for assembling are placed.

  Conventionally, when specifying the position of a moving object or a person, an RF-ID tag is attached to a mobile object to be detected, and a plurality of fixed reading devices (wireless) whose positions are known relative or absolutely A method of reading ID information by a reader device) has been proposed.

  The tag converts the power supply signal received by the antenna into DC power and supplies it to each unit. In these systems, since the spatial range in which ID information can be read by one wireless reader device is limited, the position of the moving body can be specified depending on which reader device has read the ID information. In addition, since the ID information of the moving body can be read from a plurality of wireless reader devices, it can be estimated that the moving body exists within the overlapping range of the reading ranges.

  For example, when the reading range is somewhat overlapped between the adjacent first wireless reader device and the second wireless reader device, the directivity is increased so that reading is always performed by one wireless reader device. Can also be configured and arranged.

  In addition, in order to increase the accuracy of position specification, the reading range may be further narrowed and a large number of wireless reader devices may be arranged without gaps. In the case where the traveling direction of the moving body cannot be specified, a method of installing a plurality of wireless reader devices in a two-dimensional space has also been proposed (see, for example, Patent Documents 1, 2, and 3).

  In order to improve the accuracy of position identification, a configuration is proposed in which a large number of ID tags having a relatively small installation area are installed on the floor or the ground instead of the wireless reader device, and the wireless reader device is attached to the moving body ( For example, see Patent Document 4).

  When a plurality of ID tags are attached to the mobile body, or when reading a plurality of ID tags provided with a wireless reader device attached to the mobile body, a plurality of ID tags are received in response to a read request. It will respond at the same time.

  In general, reading of RF-ID is based on the premise that the reader device and the ID tag communicate on a one-to-one basis, and therefore, an anti-collision technique that prevents a plurality of ID tags from responding simultaneously is used. Utilizing the fact that unique ID information is assigned to the ID tag, the time and order of response are determined from the ID information, and a plurality of ID tags do not respond at the same time.

JP 2004-286668 A (FIG. 1, paragraph [0036]) Japanese Patent Laying-Open No. 2004-31289 (FIG. 1, paragraph [0025]) Japanese Patent Laying-Open No. 2002-058648 (FIG. 1, paragraph [0008]) JP 2001-183455 A (FIG. 1, paragraph [0013])

However, the above-described conventional technique has the following problems.
That is, if the detection range of the wireless reader device is expanded, the approximate position or presence / absence of the moving object can be grasped, but the position cannot be detected and specified with high accuracy.

  In addition, if the detection range of the wireless reader device is narrowed to increase the accuracy of position detection, reading may fail if the moving body is larger than the antenna of the wireless reader device or if the moving speed is relatively high There is also sex.

  In order to solve these problems, when a plurality of ID tags are attached to the moving body, it is indispensable to introduce an anti-collision technique for avoiding the occurrence of collision due to simultaneous reading.

  However, in general, as the number of ID tags attached increases, the time required for reading increases, so that there may be cases where reading is impossible even though the detection range is passed. This also differs depending on the speed of the moving body and the timing at which reading is performed.

  Also, in order to perform anti-collision at high speed, it is essential to implement a dedicated circuit and protocol for defining the response timing. These not only cause an increase in cost, but also have a problem that they cannot be used on general-purpose ID tags or international standard protocols.

  The present invention has been made in view of such a problem, and an object of the present invention is to realize a reading system that maintains a high position detection accuracy, is high-speed, and has a high reading probability with little missing.

  In the reading system according to the present invention, in a reading system in which a plurality of identifiers attached to an object to be measured are read by a wireless reader device, an assignment for assigning a time slot using a part or all of information included in each identifier is performed. And a plurality of identifiers selected in advance so that the information defining the assignment by the assigning means is all different in a single reading opportunity.

  The reading method of the present invention is a reading method in which a plurality of different identifiers are attached to an object to be measured, and the plurality of identifiers are read by a wireless reader device, and part or all of the information that each of the plurality of identifiers has And assigning the plurality of identifiers to the object to be measured by preselecting the information defining the assignment so that they are all different at a single reading opportunity. Features.

  The position information transmitting apparatus of the present invention is a position information transmitting apparatus configured by a plurality of identifiers attached to a moving body to provide position information, and uses part or all of the information of the plurality of identifiers. The time slots are allotted, and the information defining the assignment is selected to be all different at a single reading opportunity.

  A program according to the present invention is a program for attaching a plurality of different identifiers to an object to be measured and causing a computer to execute a reading method for reading the plurality of identifiers using a wireless reader device. An allocation step of allocating a time slot using a part or all of the information, and preselecting the information defining the allocation so that they are all different at a single reading opportunity and assigning the plurality of identifiers to the device under test It is characterized by having a computer execute a reading method to be attached.

  According to the present invention, since a plurality of identifiers having ID information that does not cause a collision with respect to a single read request are attached to the moving body, ID tags equal to or less than the allocated time slots are attached. As long as the moving body is larger than the detector of the wireless reader device, or as a result of narrowing the detection range in order to improve the position detection accuracy, even if the time that can be read is relatively short, Reliable reading can be realized.

Embodiments of the present invention will be described below with reference to the drawings.
(First embodiment)
First, a first embodiment for realizing the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing an example of attaching an identifier having ID information in the first embodiment for explaining the features of the present invention.

  In FIG. 1, reference numeral 101 denotes a moving body that is a detection target. In the present embodiment, a cell production process is assumed, and the moving body 101 is a product assembly cart. It is assumed that the worker who performs the assembly work assembles the product on this carriage and manually moves to the next process when the work process is completed. The arrows in FIG. 1 indicate the traveling direction of the moving body 101. Reference numerals 102 a to 102 d are identifiers attached to the moving body 101.

  In this embodiment, an RF-ID tag that performs non-contact communication using electromagnetic induction is assumed as the identifiers 102a to 102d. In this example, it is assumed that four tags are attached to the mobile object 101, and a part of the unique ID is used as information for time slot assignment.

  Among the unique IDs, ID information used for assignment is selected so as not to overlap each other. It is assumed that the ID tag 102a has ID information “0”, 102b “1”, 102c “2”, and 102d “3”.

  Reference numeral 103 denotes an antenna that generates a magnetic field for reading the ID information of the identifier 102 attached to the moving body 101. In order to specify the position of the moving body 101, the antenna 103 is assumed to be laid and fixed on the floor. In this example, the width of the antenna 103 is assumed to be smaller than that of the moving body 101 in consideration of the purpose of detecting the position of the assembly cart that is the moving body 101 with high accuracy.

  However, a length that can sufficiently read each attached ID tag is secured. Further, the length of the antenna 103 is made larger than that of the moving body 101 so that there is no failure in reading. A reader device 104 is connected to the antenna 103. As part of the system described later, reading control for position detection is performed.

  As shown in FIG. 1, each identifier is selected and attached to the mobile unit 101 so that a part of the information of the unique ID used for time slot allocation does not overlap. In this example, four ID tags are attached. However, as many ID tags can be attached to one mobile body 101 as can be responded without overlapping by one reading.

  In ISO15693, a 16-slot mode is defined. In this case, 16 ID tags are selected so that a part of the ID information does not overlap and attached to one mobile unit 101, so that a single read request can be made. All ID tags can respond without collision. A case where a plurality of moving bodies pass through the antenna 103 simultaneously will be described in another embodiment.

FIG. 2 is a schematic diagram showing a relationship among an antenna, a detection target, and a process.
FIG. 2A shows the relationship between the antenna installed in the factory and each process. Reference numerals 201a and 201b denote antennas for reading ID tags, and are laid at the boundary of each process.

  The antenna 201a is disposed at the boundary between the (N-1) th process and the Nth process, and the antenna 201b is disposed at the boundary between the Nth and N + 1th processes. And when the ID tag is detected by the antenna 201a, it means that the cart which is the detection target and is also a moving object is carried out from the process N-1 and carried into the process N which is the next process.

  Actually, a plurality of ID tags are attached to a cart that is a moving body, and a plurality of pieces of tag information are read when passing through an antenna. For this reason, the time when the ID tag is first detected is regarded as the time when the process N-1 is completed, and the time when the ID tag is finally detected is regarded as the time when the process N is started.

  Whether or not the ID tag has been detected at the end cannot be determined at that time, so the reading of the ID tag of the target mobile object has been performed at an arbitrary time after the reading. If there is not, or if it is detected by the next antenna that considers the end of the process that the process has proceeded to the next process, the last detected time is determined.

  FIG. 2B to FIG. 2E show the relationship between the movement of the cart to be detected and the process. Reference numeral 202 denotes a cart that is a detection target and is also a moving body. A plurality of ID tags (not shown) are attached to the carriage 202.

  In FIG. 2 (b), the carriage 202 exists in the process N-1, and it is considered that the work is performed in the process. In FIG.2 (c), the trolley | bogie 202 has passed on the antenna 201a, and grasp | ascertains the time which specifies the work start of the process N which is the next process simultaneously with the completion | finish of the process N-1 by the detection of an ID tag. It will be.

  FIG. 2D shows a state in which work is performed in the process N after passing through the antenna 201a. FIG. 2E shows that the antenna 201b has passed and the work of the process N + 1 that is the next process is started simultaneously with the completion of the work of the process N. In this way, by detecting the passage of the antennas 201a and 201b provided between the respective processes, it is possible to grasp the end of work in a certain process and the start of the next process based on the detection time of the ID tag. .

  FIG. 2F shows the relationship between the reading time of each antenna 201a and 201b and the working time in the process. t1 indicates the reading start time at the antenna 201a, and t2 indicates the reading end time. Similarly, t3 indicates the reading start time at the antenna 201b.

  The start time of the process is t2 when the carriage has passed through the antenna, and the end time is t3 when reading with the next antenna is started. Therefore, the working time of the process N is a time between the times t3 and t2, and T in FIG. If there is only one response due to reading of the ID tag, t1 = t2, and it is assumed that the time of the previous process and the time of the next process are the same.

FIG. 3 is a diagram showing a configuration of the entire reading system.
Reference numeral 301 denotes an ID tag attached to the moving body. It is assumed that a plurality of ID tags are attached to a cart (not shown (cart 202 in FIG. 2)) that is a moving body. Reference numeral 302 denotes an antenna for detecting the ID tag 301. Reference numeral 303 denotes a reader device for controlling transmission / reception performed with the ID tag 301 via the antenna 302.

  Reference numeral 304 denotes a controller that controls a plurality of reader devices 303. Reference numeral 305 denotes a server having a function for grasping the work time of each process from the detection information obtained from the controller 304. In FIG. 3, there is one controller 304 connected to the server 305, but information from a plurality of controllers 304 can be stored in the server 305.

  In the above-described configuration, when the carriage to which the ID tag 301 is attached moves on the antenna 302, a reading request from the reader device 303 to the ID tag 301 is issued. When the ID information is detected, the detection time is given by any one of the reader device 303, the controller 304, or the server 305, and thereafter used as a parameter for managing the work time.

  The time may be given in any process, but when it is performed by the reader device 303 which is the end, it is necessary to set the time of each reader device 303 relatively to the reference time. In the case of granting on the server 305 side, which is an upstream process, the time management is unified, but a delay is caused by an amount of time until an event indicating detection from each reader device 303 comes up. Here, for convenience, the apparatus is divided for each function. However, for example, the controller 304 and the reader apparatus 303 may be integrated, and the system may be configured by an apparatus that integrates a plurality of functions.

FIG. 4 is a diagram showing the concept of the 16 slot mode.
The 16-slot mode is a mode for reading a plurality of ID tags 301 stipulated in ISO 15693, and is one of anti-collision techniques for avoiding collisions by assigning time slots.

  As shown in FIG. 4, the reader device transmits a command for obtaining a unique ID called an Inventory command to the ID tag 301. In this command, a flag for selecting a 1-slot mode for reading only one tag that does not consider anti-collision or a 16-slot mode is prepared.

  The ID tag 301 that has received the request command with the 16-slot mode flag set sees some information used for time slot allocation in the 16-slot mode among the unique IDs that are unique ID information of the ID tag 301. To determine at what timing it should respond.

  Each allocation is called a slot, and 16 slots from Slot 0 to 15 are prepared. In the case of the ID tag 301 that responds itself with Slot 0, a response is returned to the reader device within a specified time.

  Even when there is no response from the ID tag 301 in the corresponding slot or when a plurality of ID tags 301 respond simultaneously and cannot be discriminated, the end of the frame called EOF is detected from the reader device side when the specified time has elapsed. Sends the meaning packet and prompts the transition to the next slot.

  In the following, if there is a tag to be responded in each slot in order, the response is made respectively, and if there is no tag or a collision occurs, the process proceeds to the next slot after a specified time. Finally, when the 16th slot 15 ends, an EOF is transmitted and the operation in this mode ends.

  When all ID tags 301 need to be read, the ID information used for time slot allocation is changed so that collision does not occur, and a read request command is transmitted again. In this embodiment, since it is assumed that reading is completed with a single reading request, it is not necessary to change information. In addition, if any one of the plurality of ID tags 301 attached to the moving body is read, it is considered that the position has been detected.

FIG. 5 is a diagram illustrating an example of a unique ID possessed by the ID tag 301 serving as an identifier.
It will be described below that collision does not occur as long as the 16 ID tags 301 having the unique ID shown in FIG. 5 are used.

  ID tag numbers are given for convenience and need not be in this order. In this example, the unique ID is 64 bits, of which 4 bits are used for time slot allocation.

  That is, 60 bits other than the 4 bits to be used may be any value, and no limitation is imposed on the allocation of ID information or the like. Here, it is assumed that the upper 60 bits are arbitrary, this bit string is masked, and allocation is performed according to the last 4 bits of information. The last 4 bits of the ID tag number 0 are “0000”, which indicates that no other ID tag has the same ID tag.

  Similarly, ID tag number 1 is “0001” and ID tag number 2 is “0010”. In this way, if ID tags having different information used for allocation are prepared, no matter how many of them are used or any attachment method to the moving body, no collision occurs. . For this reason, the possibility that some kind of response is returned by a single read request is higher than when collision occurs.

FIG. 6 is a diagram showing the relationship of response time depending on the presence or absence of an identifier.
FIG. 6A shows the relationship when there is an ID tag that should respond to the corresponding slot in the 16-slot mode. Assuming that the time from when the Inventory command is sent until the response of Slot 0 is returned is T0, and the time until the response of Slot 1 is returned is T1, T0 is 5.98 msec by regulation, and 4.41 msec after T1. It will take a long time.

  Therefore, if all 16 ID tags respond, a time of “5.98 + 4.41 × 15 = 72.13 msec” is required (strictly, this includes the time of EOF). FIG. 6B shows the relationship when there is no ID tag to respond to the corresponding slot in the 16-slot mode.

  Similarly, if the time to response is T0 and T1, T0 takes 2.07 msec, and after T1, it takes 0.50 msec. Therefore, when there is no ID tag to be responded to, the response mode by one request command is completed in the time of “2.07 + 0.50 × 15 = 9.57 msec”. How this area relates to the ID information used for time slot allocation will be described with reference to FIG.

FIG. 7 is a diagram showing a response sequence according to a difference in ID information used for time slot allocation.
FIG. 7A shows a response sequence when the ID information used for time slot allocation is “0000”, that is, only an ID tag responding with Slot 0 is attached. As shown in FIG. 7, after receiving the request command, the response is returned in the first slot, Slot 0, so that the response is completed in time T1. The value of T1 is “5.98 msec” because it corresponds to T0 in FIG. Thereafter, since there is no tag, an EOF indicating a timeout is sent from the reader device side.

  FIG. 7B shows a response sequence when the ID information used for time slot allocation is “1111”, that is, only a tag that responds in slot 15 is attached. Similarly, after receiving the request command, a response is returned in the slot 15 which is the last slot, so that the response is completed in time T2.

  The value of T2 is “2.07 + 0.50 × 14 + 4.41 = 13.48 msec”. Thus, depending on the ID information used for time slot allocation, it can be seen that there is a difference in the time from when a request command is received until a response is returned.

  FIG. 7C is a diagram illustrating the relationship between the ID tag and the reading range. Reference numeral 701 denotes an antenna whose width indicates a reading range at the same time. The length L is the length in the width direction of the antenna. Reference numeral 702 denotes an ID tag, which has a length L1 with respect to the moving direction.

  When the ID tag 702 moves, it can accept a request command and transmit a response, that is, communicate with a reader device while it is within the range shown in FIG. Since the moving distance is L2, when moving at the speed v, the communication time t is “t = L2 / v”.

  Since making the ID tag read more reliable also means increasing the communication time, it can be seen from the above formulas that it is effective to increase the reading width or to reduce the moving speed.

  However, increasing the reading width has a problem in that the accuracy of position detection is lowered in addition to the problem in forming the antenna. Moreover, since the moving speed differs depending on the target system, there is a problem that it cannot be generally slowed down.

  In particular, in detecting the position of the carriage in cell production assumed in the present embodiment, it is difficult to define the speed at a constant speed because the carriage is moved by a person. It should be noted that there is another parameter regarding whether or not the reading is surely performed, and it is necessary to consider this. That is, the ID tag cannot return a response with a probability of 100% for a single read request.

  This is because the communication between the ID tag and the reader device is based on electromagnetic induction, so if there is a metal nearby or if other electromagnetic waves exist as noise, a bit error will occur and reading will fail. Will fail. In a very primitive transponder that does not have an error correction function such as RF-ID, a drop in reading accuracy due to these causes is solved by repeatedly issuing a request command.

  For this reason, it is important to make the time from the request command reception to the response as early as possible, and to execute the repeated request as soon as possible after the mode ends. The result of having performed a simulation about the influence of the difference in the ID information and the length L1 with respect to the moving direction of the ID tag is shown below.

FIG. 8 is a simulation result showing the relationship between the ID information and the reading probability.
FIG. 8A verifies the detection probability in three different ID information. This is a simulation result assuming that the length relative to the moving direction is the short side direction when the ID tag has a card size (85.60 mm × 53.98 mm) defined by ISO 7810 called “ID-1”. . There are three types of ID information: ID0 = “0000”, ID7 = “0111”, and ID15 = “1111”. The detection probability is considered to be 100% if reading is performed even once.

  As shown in FIG. 8, it can be seen that the detection probability starts to drop when the moving speed exceeds 4 km / h, and a difference of nearly 5% is obtained at a speed of 10 km / h. By the way, the width of the antenna is 125mm, and the probability that a response will be returned by one reading is calculated as 80% (actually, the probability of response is not so far, it is said to be about 92% to 95%) ing.).

  FIG. 8B is basically the same as FIG. 8A, but the time in the detection range is shorter because the length with respect to the moving direction is the long side direction of the ID tag. It can be seen that there is more difference.

  There is a difference of about 15% at a speed of 7 km / h and 50% or more at a speed of 10 km / h. In this simulation, the calculation is performed with a constant time from one read request to the next read request. Needless to say, when the response mode for one read request is completed, the probability of detection is higher when the next read request is started immediately.

  FIG. 8C shows the verification probability of two different ID information. The difference from FIG. 8B is that information on the number of readings is added in addition to the detection probability.

  Thus, it can be seen that the detection probability of the ID tag varies depending on the difference in ID information even at the same moving speed. Further, if the width of the antenna reading range is narrowed, the detection probability is further lowered.

  From the above, it can be seen that when attaching a plurality of ID tags to a mobile object, it is effective to attach them in order from the one with the shortest time to response. It is also clear that it is desirable to attach the tag with the shortest response time at the position where the attachment position first enters the detection range in the traveling direction.

  At first glance, it seems that the total response time does not change because the individual response time does not change regardless of the position of the moving body. However, if another ID tag is read before reading the ID tag with the shortest response time, the reading of the ID tag may fail, or the mobile object may pass before returning a response. Will delay the reading timing, resulting in a lower detection probability.

  In the present embodiment, the description has been made based on a specific standard. However, a general-purpose standard is not limited to this. As a result, the number of ID tags that can be employed without causing a collision may vary from 16.

  As described above, in the present embodiment, a plurality of identifiers having ID information that does not cause a collision with respect to a single read request are attached to the moving body. As a result, as long as an ID tag equal to or less than the allocated time slot is attached, if the moving body is larger than the detector of the wireless reader device, or as a result of narrowing the detection range to increase the position detection accuracy, Even if the time during which reading is relatively possible is shortened, high-speed and reliable reading can be realized.

  In addition, by attaching from the ID tag with the earliest time slot assignment order, it is possible to reduce the time required for reading and increase the certainty of reading. Furthermore, when the moving direction of the moving body is determined, the time required for reading is shortened by attaching a tag with the shortest time to response to the side where the moving body is facing the moving direction. Certainty could be further improved.

  Also, if the moving direction of the moving body is not fixed, attach the tag to the detector in order from the one with the shortest time to response to several sides where movement is expected. It is possible to perform reading in a relatively short time even if the vehicle enters. By performing these, in this embodiment, it is possible to realize reliable reading without using a unique anti-collision technique that realizes high-speed reading. For this reason, it is possible to implement a reading system using a general-purpose RF-ID tag and a wireless reader device compliant with international standards such as ISO15693 and ISO18000.

(Second Embodiment)
A second embodiment for realizing the present invention will be described with reference to the drawings.
The feature of the reading system that realizes the present embodiment is that, in the first embodiment, there is one moving body that passes through the antenna, but it can be detected even when a plurality of moving bodies pass through the antenna. . The contents will be described focusing on this point.

FIG. 9 is a diagram showing an example of attaching an identifier having ID information in the second embodiment for explaining the features of the present invention.
In FIG. 9, reference numerals 901 and 902 denote moving bodies that are detection targets. The arrows in FIG. 9 indicate the traveling directions of the moving bodies 901 and 902. Reference numerals 903a to 903d denote identifiers attached to the moving body 901. Reference numerals 904a to 904d denote identifiers attached to the moving object 902.

  In this example, it is assumed that four ID tags are attached to the mobile units 901 and 902, and a part of the unique ID is used as information for time slot allocation.

  Among the unique IDs, the ID information used for assignment is selected so that the two mobile units do not overlap each other. The ID tag 903a has identification information of “0”, 903b has “2”, 903c has “4”, and 903d has “6”. The ID tag 904a has identification information “1”, 904b “3”, 904c “5”, and 904d “7”.

  Reference numeral 905 denotes an antenna that generates a magnetic field for reading ID information of the identifiers 903a to 903d and 904a to 904d attached to the moving bodies 901 and 902. In order to specify the positions of the mobile bodies 901 and 902, the antenna 905 is laid on the floor and fixed, as in the first embodiment. Reference numeral 906 denotes a reader device connected to the antenna 905.

  As shown in FIG. 9, the difference from the first embodiment is that there are a plurality of moving bodies that are detected simultaneously by the antenna 905. In order to prevent collision even when reading a plurality of moving objects, an identifier may be selected and attached to the moving object so that ID information of tags that may be read simultaneously does not overlap.

FIG. 10 is a diagram illustrating a response sequence by a plurality of moving objects according to the second embodiment.
FIG. 10A shows a response sequence when the ID information used for time slot allocation is “0000”, that is, the ID tag responding with Slot 0 and the ID tag responding with Slot 1 with ID information “0001” are attached. is there.

  As shown in FIG. 10A, since the response is returned in Slot 0, which is the first slot after receiving the command, the mobile unit 901 completes the response in time T1. In addition, since the mobile unit 902 returns a response in the next slot, Slot1, the response is completed in time T2. Thereafter, when the tag does not exist, an EOF indicating a timeout is sent from the reader device side.

  FIG. 10B shows a response sequence when the ID information used for time slot allocation is “0100”, that is, the ID tag responding with Slot 4 and the ID tag responding with Slot 5 with ID information “0101” are attached. . Similarly, after receiving the request command, the mobile unit 901 returns a response in slot 4 and the mobile unit 902 returns a response in slot 5, so that the response is completed at times T3 and T4, respectively.

  As described above, depending on the ID information used for time slot allocation, there is a difference in the time from when a request command is received until a response is returned. As long as an identifier having ID information that does not occur is attached, reading can be completed with a single request command.

  As described above, even when a plurality of targets whose positions are to be specified enter the detection range at the same time, the ID information attached to each target is selected so that it does not overlap as time slot allocation information. Reading can be realized.

(Third embodiment)
A third embodiment for realizing the present invention will be described with reference to the drawings.
The feature of the reading system that realizes the present embodiment is that, in the first embodiment, if the moving body is rectangular so that the attachment positions of the ID tags are farthest from each other, they are arranged diagonally. The ID tag is arranged so that the distance between the ID tags is shortened. In the first embodiment, the configuration in the case where four tags are used has been described. However, it is assumed that the number of tags is larger. In this case, there are a plurality of ID tags on the same side, and a plurality of ID tags are read at the time of reading. The contents will be described focusing on these points.

  FIG. 11 is a diagram showing an example of attaching four identifiers having ID information in the third embodiment.

  In FIG. 11, reference numeral 1101 denotes a moving body (assembly cart) that is a detection target. The arrows in the figure indicate the traveling direction of the moving body 1101. Reference numeral 1102 denotes an identifier attached to the moving object 101. In this example, it is assumed that four tags are attached to the mobile object 1101, and a part of the unique ID is used as information for time slot assignment.

  Among the unique IDs, ID information used for assignment is selected so as not to overlap each other. It is assumed that the ID tag 1102a has identification information “0”, 1102b “1”, 1102c “2”, and 1102d “3”. Reference numeral 1103 denotes an antenna that generates a magnetic field for reading the ID information of the identifier 102 attached to the moving body 101. Reference numeral 1104 denotes a reader device connected to the antenna 1103.

  As shown in FIG. 11, the difference from the first embodiment is that the attachment position of the ID tag is different. The feature is that the distance is short, not the diagonal position of the rectangle, so that the positional relationship is farthest. If the side of the carriage is perpendicular to the traveling direction, other ID tags are not read when the tag of the ID tag 1102a is read.

  In the first embodiment, the ID tags 102a and 102b are to be read at the same time. However, more reliable reading can be performed by using this embodiment. In addition, in the case of erroneously returning after entering the next step once, since the reading is not performed even if the corner enters the detection range, it is possible to ensure the reliability as the reading system. However, the reliability is reduced when the carriage enters obliquely with respect to the traveling direction. The attachment position of the first embodiment is not a matter of which is better, but it is desirable to change according to the form and application to be applied.

FIG. 12 is a diagram showing an example of attachment of 16 identifiers having ID information in the third embodiment.
In FIG. 12, reference numeral 1201 denotes a moving body (assembly cart) that is a detection target. Reference numeral 1202 denotes an identifier attached to the moving body 1201, and a total of 16 tags are attached.

  The difference between the first embodiment and the third embodiment is the number of attached ID tags, but by placing tags with a relatively fast response time regardless of the direction of entry, reliable reading is possible. It becomes the composition which increases the nature. In addition, since the number of sheets increases, the time required for the response mode to end with respect to a single read request becomes longer, but a plurality of ID tags are read regardless of the angle of entry.

  As described above, by considering the attachment position and the number of attachments of the ID tag, it is possible to adopt a configuration that considers the purpose, application, and approach direction. As a result, high-speed and reliable reading can be realized as in the other embodiments.

(Other embodiments according to the present invention)
Each means constituting the reading system and each step of the reading method in the embodiment of the present invention described above can be realized by operating a program stored in a RAM or ROM of a computer. This program and a computer-readable recording medium recording the program are included in the present invention.

  Further, the present invention can be embodied as a system, apparatus, method, program, storage medium, or the like. Specifically, the present invention may be applied to a system composed of a plurality of devices, or may be applied to an apparatus composed of one device.

  In the present invention, a software program that implements the functions of the above-described embodiments may be directly applied to a system or apparatus. Alternatively, it may be achieved by supplying from a remote location and the computer of the system or apparatus reads and executes the supplied program code.

  Accordingly, since the functions of the present invention are implemented by computer, the program code installed in the computer also implements the present invention. In other words, the present invention includes a computer program itself for realizing the functional processing of the present invention.

  In that case, as long as it has the function of a program, it may be in the form of object code, a program executed by an interpreter, script data supplied to the OS, and the like.

  Examples of the recording medium for supplying the program include a floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, MO, CD-ROM, CD-R, and CD-RW. Moreover, a magnetic tape, a non-volatile memory card, ROM, DVD (DVD-ROM, DVD-R), etc. are also included.

  As another program supply method, the program can be supplied by connecting to a homepage on the Internet using a browser of a client computer and downloading the computer program of the present invention from the homepage. Alternatively, it can be supplied by downloading a compressed file including an automatic installation function to a recording medium such as a hard disk.

  It can also be realized by dividing the program code constituting the program of the present invention into a plurality of files and downloading each file from a different homepage. That is, a WWW server that allows a plurality of users to download a program file for realizing the functional processing of the present invention on a computer is also included in the present invention.

  In addition, the program of the present invention is encrypted, stored in a storage medium such as a CD-ROM, distributed to users, and key information for decryption is downloaded from a homepage via the Internet to users who have cleared predetermined conditions. Let It is also possible to execute the encrypted program by using the key information and install the program on a computer.

  Further, the functions of the above-described embodiments are realized by the computer executing the read program. In addition, based on the instructions of the program, the OS or the like running on the computer performs part or all of the actual processing, and the functions of the above-described embodiments can be realized by the processing.

  Further, the program read from the recording medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. Then, based on the instructions of the program, the CPU or the like provided in the function expansion board or function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

  As described above, according to the above description, since a plurality of identifiers having ID information that does not cause a collision with respect to a single read request are attached to the mobile body, IDs equal to or less than the time slot allocation amount As long as the tag is attached, when the moving body is larger than the detector of the wireless reader device, or as a result of narrowing the detection range to increase the position detection accuracy, the time that can be read relatively decreases. However, high-speed and reliable reading can be realized. In addition, since the ID tags are assigned from the earliest time slot assignment order, the time required for reading can be shortened, and the read reliability can be improved.

  Furthermore, when the traveling direction of the moving body is determined, the ID tag having the shortest time to response is attached to the side on which the moving body faces the traveling direction, so that the time required for reading is shortened, The certainty of reading can be further improved.

  In addition, when the traveling direction of the moving body is not fixed, the ID tag is attached in order from a short response time to several sides that are supposed to move. Even if it enters the instrument, reading can be performed in a relatively short time.

  In addition, since it is possible to configure a system without using a unique anti-collision technology that realizes high-speed reading, a general-purpose RF-ID tag and a wireless reader device compliant with international standards such as ISO15693 and ISO18000 are provided. Can be used to configure the system.

It is the figure which showed the example of attachment of the identifier with ID information in 1st Embodiment. It is the schematic diagram which showed the relationship between the antenna in 1st Embodiment, a to-be-detected object, and a process. It is a figure showing composition of the whole system in a 1st embodiment. It is the figure which showed the concept of 16 slot mode in 1st Embodiment. It is the figure which showed the example of the unique ID which the identifier in 1st Embodiment has. It is the figure which showed the relationship of the response time by the presence or absence of the identifier in 1st Embodiment. It is the figure which showed the response sequence by the difference in ID information in 1st Embodiment. It is the figure which showed the simulation result which shows the relationship between ID information and the reading probability in 1st Embodiment. It is the figure which showed the example of attachment of the identifier with ID information in 2nd Embodiment. It is the figure which showed the response sequence by the some to-be-measured object in 2nd Embodiment. It is the figure which showed the example of attachment of 4 identifiers with ID information in 3rd Embodiment. It is the figure which showed the example of attachment of 16 identifiers with ID information in 3rd Embodiment.

Explanation of symbols

101 Moving object (Detected object (product assembly cart))
102 Identifier (ID tag)
102a Identifier 102 with Time Slot Assignment Definition Information 0 b Identifier 102 with Time Slot Assignment Definition Information 1 102c Identifier 102 with Time Slot Assignment Definition Information 2 d Identifier with Time Slot Assignment Definition Information 3 103 Antenna 104 Reader Device

Claims (15)

In a reading system in which a wireless reader device reads a plurality of identifiers attached to a measurement object,
Allocation means for performing time slot allocation using part or all of the information of each identifier;
A reading system, wherein a plurality of identifiers selected in advance so that information defining assignment by the assigning means is all different in one reading opportunity are attached to the object to be measured.   The reading system according to claim 1, wherein the identifier is attached to the object to be measured in order from an identifier having a higher time slot use order.   In the relative movement relationship between the object to be measured and the wireless reader device, when the movement direction is determined in advance, an identifier with the earliest time slot usage order is attached from the movement direction side. The reading system according to claim 2.   In the relative movement relationship between the object to be measured and the wireless reader device, when the movement direction is not fixed in advance, an identifier having a fast time slot usage order for several directions in which movement is assumed. The reading system according to claim 2, which is attached in order.   One of the object to be measured or the wireless reader device is fixed, and has position specifying means for determining the position of the object to be measured by grasping the position when reading at the fixed position. The reading system according to any one of claims 1 to 4, characterized in that:   The reading system according to claim 1, wherein the position of the device under test is specified by recognizing one of the plurality of different identifiers.   The time measuring means for acquiring the time when the reading is performed is disposed in the wireless reader device or in a reading system including the device. Reading system.   The wireless reader device is arranged at the entrance and exit of each process in the cell production system in which a person carries out work in progress as work progresses, and the work time of each process is calculated from the reading time of the time measuring means. The reading system according to claim 7.   9. The reading according to claim 8, wherein when the steps are adjacent to each other, the entrance and the exit are regarded as one position, and the time of exiting from one step is determined as the time of entering the next step. system.   The reading system according to any one of claims 1 to 9, wherein the identifier is attached to the device under test on the outer periphery of the device under test.   11. The request for reading using the time slot is repeatedly performed at the time when one reading opportunity is completed regardless of the presence or absence of the identifier. Reading system as described in. A reading method in which a plurality of different identifiers are attached to a device under test, and the plurality of identifiers are read by a wireless reader device,
An allocation step of performing time slot allocation using part or all of the information of each of the plurality of identifiers,
A reading method characterized in that the information defining the assignment is selected in advance so as to be all different in a single reading opportunity, and the plurality of identifiers are attached to the object to be measured. A position information transmitting device configured by a plurality of identifiers attached to a moving body to provide position information,
Time slot allocation is performed using part or all of information included in the plurality of identifiers, and the information defining the allocation is selected to be all different at a single reading opportunity. Position information transmission device to perform. A program for causing a computer to execute a reading method of attaching a plurality of different identifiers to a device under test and reading the plurality of identifiers by a wireless reader device,
An allocation step of performing time slot allocation using part or all of the information of each of the plurality of identifiers,
A program for causing a computer to execute a reading method for attaching the plurality of identifiers to the object to be measured by selecting in advance the information defining the allocation so that they are all different in a single reading opportunity.   A computer-readable recording medium on which the program according to claim 14 is recorded.

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