Patent Application
20100289624
1. Field of the Invention
The present invention relates to an apparatus for communicating with a radio frequency identification (RFID) tag that reads information from an RFID tag capable of radio communication of information with the outside.
2. Description of the Related Art
A radio frequency identification (hereinafter referred to as RFID) system that reads and writes information with respect to a small-sized RFID tag is known. A reader/writer disposed in the RFID system transmits an inquiry to an RFID tag and receives a reply in a non-contact manner.
There is an apparatus for communicating with an RFID tag that smoothly conducts communication with an RFID tag circuit element used in such RFID system.
With this prior art reference, a tag reader as an apparatus for communicating with an RFID tag is mounted on an article management robot. The tag reader reads information transmitted from an ID tag as an RFID tag circuit element. By means of cyclic movement of the article management robot, the apparatus for communicating with an RFID tag mounted on the article management robot detects an RFID tag circuit element disposed in each article. Then, the position of the article is detected based on the position of the article management robot at the detection, and the detected position is notified to an operator by a display.
However, the above-described prior art reference has the following problems.
That is, there is a case that an operator uses a handheld apparatus for communicating with an RFID tag in a warehouse, for example. In this case, in order to detect an RFID tag circuit element disposed in each of a plurality of articles, that is, in order to obtain information, the operator often carries the apparatus for communicating with an RFID tag in the hand and swings it around when communication is conducted. If a direction of information transmission and reception by the apparatus for communicating with an RFID tag is on an apparatus front side, for example, a front direction of the apparatus for communicating with an RFID tag when information can be obtained from the RFID tag circuit element becomes a direction where the corresponding RFID tag circuit element is present. Therefore, when the information is obtained, if the apparatus for communicating with an RFID tag notifies the operator of the information obtainment, the operator can gain knowledge of the presence direction of the RFID tag circuit element, that is, the presence direction of the article.
As described above, if a signal is received from the RFID tag circuit element and it is notified to the operator, actually there is a time delay till the notification in the apparatus for communicating with an RFID tag. The time delay is a delay caused by processing time for reception processing of a response signal from the RFID tag circuit element, operation time of notification means for making notification after the processing, for example. If the movement or a change in the direction of the apparatus for communicating with an RFID tag is relatively fast, even while the above-described slight processing time and operation time, for example, elapsed, the apparatus for communicating with an RFID tag can largely progress. The operator's swinging operation corresponds to the fast movement and change in the direction. Thus, there can be a deviation between the position or direction of the apparatus for communicating with an RFID tag when a signal is received from the RFID tag circuit element and the position or direction of the apparatus for communicating with an RFID tag when the processing has been finished and that is notified by the notification means. In this case, there is a fear that substantially accurate notification cannot be made to the operator.
With the apparatus of the prior art reference, the time delay that can be caused with respect to the fast movement of the apparatus for communicating with an RFID tag from signal reception to notification is not particularly assumed. Therefore, it has been difficult to make accurate notification in response to the signal reception in the above case.
An object of the present invention is to provide an apparatus for communicating with an RFID tag that can make accurate notification to an operator in response to the signal reception from the RFID tag circuit element.
An embodiment of the present invention will be described below referring to the attached drawings.
As shown in
A reader 1, which is an apparatus for communicating with an RFID tag of this embodiment is a movable type and a handheld type in this example. The reader 1 has a housing 11 generally formed in a rectangular solid shape and a reader antenna as an apparatus antenna. The reader antenna 3 in this example has a sharp directivity. That is, a half power angle of the reader antenna 3 is small and the width of a communicable area 20 is small. Moreover, a main lobe direction M of the reader antenna 3 substantially matches the longitudinal direction of the housing 11.
An operator of the reader 1 is an administrator of the book 201, for example. The operator moves the reader 1 substantially along the direction where the plurality of books 201 are aligned by carrying the reader 1 in the hand and by moving it by swinging the arm substantially in the arc state, for example. The present invention can be applied to the case in which the reader 1 moves linearly or makes a circular motion. By means of this movement, the communicable area 20 of the reader antenna 3 passes an alignment range of the plurality of books 201 at a moving speed V. The moving speed is a peripheral speed in this example. Also, the RFID tag T attached to the search target book will be referred to as a target tag Tt as appropriate. If the target tag Tt is located in the longitudinal direction of the housing 11, which is a reference search direction of the reader 1, that is, in the vicinity of the main lobe direction of the reader antenna 3, identification information of the target tag Tt is received via radio communication through the reader antenna 3. The identification information of the target tag Tt will be referred to as a target tag ID as appropriate. As a result, the reader 1 can detect the presence position of the search target book or the presence direction from the reader 1.
As shown in
The main body control part 2 includes a CPU 4, a memory 5, a timer 6, a display part 8 as a notification device, an acceleration sensor 9 as a movement detecting device, the memory 5 including a RAM and a ROM, for example, the timer 6 having a clocking function, and a radio frequency (RF) communication control portion 10. An operation part 7 receives an input of an instruction and information from the operator. The display part 8 displays various types of information and messages. The acceleration sensor 9 detects movement acceleration when the reader 1 moves. The RF communication control portion 10 controls radio communication with the RFID tag T through the reader antenna 3.
The CPU 4 performs signal processing according to a program stored in the ROM in advance using a temporary storage function of the RAM. The CPU 4 performs various controls of the entire reader 1 by the signal processing.
The acceleration sensor 9 is a triaxial acceleration sensor such as a MEMS type using a known piezo resistance method or an electrostatic capacity method, for example. In this example, the acceleration sensor 9 individually detects moving acceleration in directions corresponding to the width direction, the length direction, and the thickness direction of the housing 11 of the main body control part 2 in the reader 1, respectively, that is, the moving acceleration in the coordinate axis directions in the housing 11. The width direction of the housing 11 corresponds to the right-and-left direction in
As the display part 8, in this example, an LCD which can display a text such as characters or symbols or figures, that is, a liquid crystal display is used. An example using other types of display part or notification device will be described later.
The RFID tag T has an RFID tag circuit element To provided with a tag antenna 151 and an IC circuit part 150. The RFID tag T has the RFID tag circuit element To disposed on a base material, for example, not particularly shown. The RFID tag T can be attached to an article such as the book 201.
Also, the CPU 4 processes a signal read from an IC circuit part 150 of the RFID tag circuit element To and reads information and generates a response request command to make an access to the IC circuit part 150 of the RFID tag circuit element To.
The reader antenna 3 has a sharp directivity as described above. That is, the communicable area 20 of the reader antenna 3 is formed in a narrow width and with an elongated shape in the main lobe direction. Also, the main lobe direction of the reader antenna 3 matches the longitudinal direction of the housing 11 of the reader 1. As a result, the reader 1 can conduct radio communication only with respect to the RFID tag T present in the vicinity on an extension in the longitudinal direction of the housing 11 as shown in
The RF communication control portion 10 makes an access to information of the IC circuit part 150 of the RFID tag circuit element To through the reader antenna 3, that is, the RFID tag information including the tag ID.
By using the RF communication control portion 10, the reader 1 transmits the response request command to the RFID tag circuit elements To of the RFID tags T present in the communicable area 20. The response request command functions as an inquiry signal requesting transmission of the tag ID of each of the RFID tag circuit elements To as a response signal.
As shown in
The IC circuit part 150 includes a rectification part 152, a power source part 153, a clock extraction part 154, a memory part 155, and a control part 157. The rectification part 152 rectifies an interrogation wave, which is a signal including the response request command, received by the tag antenna 151. The power source part 153 accumulates energy of the interrogation wave rectified by the rectification part 152 and uses the energy as a driving power source. The clock extraction part 154 extracts a clock signal from the interrogation wave received by the tag antenna 151 and supplies the signal to the control part 157. The memory part 155 stores a predetermined information signal. The control part 157 controls operations of the RFID tag circuit element To through the memory part 155, the clock extraction part 154, and the modem part 156, for example.
The modem part 156 demodulates a communication signal from the reader antenna 3 of the apparatus for communication with an RFID tag 1, received by the tag antenna 151 and also modulates a reply signal from the control part 157 and transmits it from the tag antenna 151 as a response wave as a response signal including a tag ID.
The clock extraction part 154 extracts a clock component from the signal received by the tag antenna 151 and extracts the clock to the control part 157. The clock extraction part 154 supplies the clock corresponding to a frequency of the clock component of the signal received by the tag antenna 151 to the control part 157.
The control part 157 interprets a received signal demodulated by the modem part 156 and generates a reply signal on the basis of the information signal stored in the memory part 155. This reply signal is modulated by the modem part 156 on the basis of control of the control part 157 and replied from the tag antenna 151. Here, if the received signal is the response request signal, the control part 157 generates a reply signal including the tag ID stored in the memory part 155 in advance, that is, a response signal. The tag ID is identification information assigned to individual RFID tag circuit element To. The generated response signal is replied from the tag antenna 151.
Subsequently, various timings and positional relationships relating to detection of the target tag Tt and notification of the fact while the reader 1 is moving will be described.
The timings and positional relationships of the detection and notification of the target tag Tt when the reader 1 and its communicable area 20 are moving will be described using
In
Also, during the movement of the reader 1, an acceleration detected value with a sign corresponding to each axial direction from the triaxial acceleration sensor 9 is integrated by interruption processing executed all the time since start of the movement, for example. As a result, a moving speed V as a moving state amount of the reader 1 during movement caused by arm swinging of the operator or the peripheral speed V in the case of the arc-state movement, for example, is calculated on a real-time basis.
If the communicable area 20 of the reader antenna 3 moving with the reader 1 reaches a presence position of the target tag Tt, the target tag ID is received by the reader 1 via radio communication. At the position of the reader 1 at that time, the target tag Tt is present the closest in the reference search direction of the reader 1, that is, in the longitudinal direction of the housing 11. Therefore, this position should have been confirmed and notified as a detected position where the target tag Tt is detected.
However, at this time, the reader 1 has merely read the target tag ID. Actually, predetermined reception processing such as verification processing to confirm that the read target tag ID is actually a search target, for example, is required after that. In the radio communication in compliance with the Class1 Generation2 (C1G2) stipulated by the EPC global, the tag ID is received from the RFID tag T in an extremely short time. In this case, for example, in the verification processing, the target tag ID is verified for each of the continuously received plurality of tag IDs, and determination is made on whether they are matched or not. Also, if a plurality of target tag IDs as search targets are set in a list, not shown, for example, it is verified if each of the plurality of received tag IDs matches the plurality of target tag IDs set in the list or not.
If reception of the target tag ID is checked after the verification processing requiring a predetermined processing time as above, the reception of the target tag ID, that is, position detection of the target tag ID is notified to the operator through a notifying device such as the display part 8 at that time. Moreover, in the notification operation, after an operation time of the display part 8, which is the notifying device, has elapsed, a notification that can be actually recognized by the operator is made. As the display part 8, a liquid crystal panel, for example, is used.
If the movement of the reader 1 is relatively fast as the search of the reader 1 by arm swinging of the operator, the reader 1 moves even during a slight elapsed time such as an execution time of the reception processing such as the verification and the operation time for notification, for example. As a result, the notification of the RFID tag detection by the display part 8 is made at a position away from the position where the reader 1 actually receives the target tag ID by a distance moved while the verification processing and the notification operation are performed. This separation distance is a distance along the arc-state orbit in the case of the above-described arc-state movement. This separation distance will be referred to as “detected position deviation” as appropriate. In this case, the presence position of the target tag Tt, that is, a containment position of the book 201 as a search target in the example shown in
Then, in this embodiment, an elapsed time from the reception of the target tag ID till the verification processing is finished is actually measured as an actual measured verification time tm by the timer 6. Also, the time estimated to be required for the notification operation is set in advance as a predetermined notification time tc, which is a fixed time. Then, the detected position deviation is calculated by integrating the moving speed V of the reader 1 with a total time of the actual measured verification time tm, which is the actual measured value, and the predetermined notification time tc, which is a fixed value. The total time corresponds to a first time state amount in this example, and the detected position deviation corresponds to a direction state amount. In the notification operation by the display part 8, the detected position deviation together with the notification of tag detection is displayed on the display part 8.
The predetermined notification time tc is set also including the time estimated to be required for the calculation of the detected position deviation, for example. Also, the detected position deviation is expressed by a direction from the current position of the reader 1 (See
Subsequently, a control procedure executed in the reader 1 of this embodiment will be described using
First, at Step S5, the CPU 4 outputs a control signal to the above-described transmitting circuit 212 for transmission of the response request command signal for reading of the tag ID. That is, the transmitting circuit 212 performs predetermined modulation so as to generate the response request command signal as an inquiry signal in this example. This response request command signal is an interrogation wave to obtain the tag ID stored in the RFID tag circuit element To of the target tag Tt as described above. The transmitting circuit 212 transmits the response request command signal to the RFID tag circuit element To of the RFID tag T present within the communicable area 20 through the reader antenna 3.
After that, at Step S10, the CPU 4 takes in the response signal transmitted from the RFID tag circuit element To of the RFID tag T in response to the response request command signal and received through the reader antenna 3, that is, the reply signal including the tag ID through a receiving circuit 213.
Subsequently, the routine goes to Step S15, and the CPU 4 starts a clocking operation by outputting a control signal to the timer 6. After that, the routine goes to Step S20.
At Step S20, the CPU 4 performs tag ID verification processing to verify if the tag ID obtained at Step S10 matches the target tag ID, which is the search target.
Subsequently, the routine goes to Step S25, and the CPU 4 determines if the target tag ID has been detected or not in the tag ID verification processing at Step S20. In other words, the CPU 4 determines if at least one of the tag IDs received at Step S10 matches the target tag ID or not. If the target tag ID has not been detected, the determination is not satisfied, and the routine goes to Step S30. At Step S30, the CPU 4 resets the clocking contents so far by stopping the operation of the timer 6, returns to Step S5 and repeats the similar procedure. As a result, if a response signal including a plurality of tag IDs is received at Step S10, the verification is repeated in the tag ID verification processing at Step S20 till the received response signal includes the tag ID which matches the target tag ID. If a plurality of the target tag IDs are set as the search targets, the verification is repeated till the received response signal includes the plurality of tag IDs which match all the plurality of target tag IDs.
On the other hand, at Step S25, if the target tag ID has been detected, the determination is satisfied, and the routine goes to the subsequent Step S35.
At Step S35, the CPU 4 calculates the moving speed V of the reader 1 at this point of time. In the calculation of the moving speed V, as described above, the CPU 4 executes interruption processing with a small time interval from the moving start of the reader 1, for example, cumulatively integrates the acceleration with a sign detected by the triaxial acceleration sensor 9, respectively, corresponding to each axial direction by a known integration method and calculates the speed.
Subsequently, the routine goes to Step S40, and the CPU 4 obtains clocking contents of the timer 6 at this time, by which the CPU 4 obtains the actual measured verification time tm, which is an actual measured value from the reception of the target tag ID at S10 to this point of time. While only a usual tag ID, which is not the target tag ID, is continuously received, the timer 6 is kept on being reset at Step S25 and Step S30.
Then, at the subsequent Step S45, the CPU 4 calculates the detected position deviation or a distance on the arc-state orbit in this example. That is, the CPU 4 calculates the total time of the actual measured verification time tm obtained at Step S40 first and the predetermined notification time tc set in advance as a fixed value. This Step S45 functions as a time calculating device described in each claim. The CPU 4 integrates the moving speed V of the reader 1 calculates at Step S35 with the total time so as to calculate the detected position deviation. The direction of the detected position deviation has a sign opposite to the sign of the moving speed V, that is, the direction is opposite to the moving direction of the reader 1.
Subsequently, the routine goes to Step S50, and the CPU 4 outputs a control signal to the display part 8. As a result, the fact that the target tag ID has been received and the presence direction of the target tag Tt, which is the original search target, corresponding to the distance and direction of the detected position deviation calculated at Step S45 are displayed on the display part 8. The presence direction of the target tag Tt is acquired by the CPU 4 through a predetermined calculation on the basis of the distance and direction of the detected position deviation at Step S45. As a result, notification is made to the operator. And this flow is finished.
If the notification is to be made, display as shown in
Here, the predetermined notification time tc used for the calculation at Step S45 is, as described above, a fixed value set in advance as time usually required from acquisition of the actual measured verification time tm at Step S40 to completion of the notification operation at Step S50. That is, the predetermined notification time tc includes both the time estimated as necessary for the calculation at Step S45 and the time estimated as necessary for display in the notification operation at Step S50.
In the above, the procedure at Step S5 in the flow of
Also, in Step S45, the calculation contents for calculating a detected position deviation by integrating the moving speed V with the total time function as a direction calculation portion. This function and the procedure at Step S50 function as a notification control portion.
As described above, in this embodiment, in response to the deviation between the position of the reader 1 when the target tag ID is received and the position of the reader 1 when notification is actually made to the display part 8, the display part 8 displays the presence direction of the target tag Tt and notifies it to the operator. As a result, the notification corresponding to the reception result of the target tag ID with accuracy, that is, the notification matching the timing of reception of the response signal can be reliably made to the operator.
Also, particularly in this embodiment, at Step S45, the CPU 4 calculates the total time of the actual measured verification time tm detected as an actual measured value from the timer 6 and the predetermined notification time tc, which is a fixed value and calculates a detected position deviation using the total time and the moving speed V of the reader 1. As a result, calculation and notification of the detected position deviation with high accuracy can be made.
Also, particularly in this embodiment, the reader 1 includes the triaxial acceleration sensor 9 which can detect the moving acceleration of the reader 1. As a result, without requiring an external aiding facility, the reader 1 can singularly detect the moving acceleration of the reader 1 from the triaxial acceleration sensor 9 and calculate the moving speed V.
In the above embodiment, as shown in
Also, as shown in
In addition to the above, though not particularly illustrated, notification can be made to the operator by a sense of touch by disposing a vibration oscillator such as a vibrator in the housing 11 of the reader 1 and using the vibration or notification can be made to the operator by a sense of hearing by disposing a sound generator such as a speaker and using sound. In these cases, it may be configured that a plurality of vibration oscillators or sound generators are disposed at positions corresponding to each direction of the detected position deviation, respectively, so that the direction of the detected position deviation can be distinguished. Alternatively, the distance of the detected position deviation can be expressed by a difference in a size of amplitude or a height of frequency of the respective vibration or sound. If the sound generator is to be used, various types of notification information may be uttered by human language.
Also, the reader 1 may include a plurality of notifying devices in a comprehensive manner. In this case, since a required time for the notification operation is different depending on the type of the notification, that is, the predetermined notification time tc which is different corresponding to the notification type of each notifying device is set. In this case, at the above-described Step S45, the predetermined notification time tc corresponding to the notification type is selected and used so as to calculate the detected position deviation. As a result, the total time of the actual measured verification time tm and the predetermined notification time tc are also selected corresponding to the notification type. For example, the operator may input which notification type is to be selected in advance by using the operation part 7. As described above, by setting the predetermined notification time tc according to the notification type such as sound, display, vibration, detailed notification of the detected position deviation is made possible, and convenience for the operator can be improved.
The present invention is not limited by the above embodiments but capable of various deformations within a range not departing from its gist and technical idea. Such variations will be described below in order.
(1) If the Entire Time from Reception of the Target Tag ID to Start of the Notification Operation is Fixedly Set:
In the above embodiment, a time element used for the calculation of the detected position deviation, that is, the time from reception of the target tag ID to start of the notification operation is calculated by totaling the actual measured verification time tm and the predetermined notification time tc. On the other hand, as sown in
This variation has the same hardware configuration as that of the above embodiment, and the same reference numerals are given to the equivalent portions and the description will be omitted as appropriate. The same applies to each of the following variations.
The control executed by the CPU 4 of the reader 1 in this variation will be described referring to
The other configurations are the same as those in
In this variation configured as above, the detected position deviation is calculated using the predetermined processing time ts set in advance in a fixed manner corresponding to the notifying device. As a result, the detected position deviation can be calculated with a relatively simple method.
(2) If a Response Delay Time of the Operator is Considered:
In the above embodiment, the time element used for the calculation of the detected position deviation is set as only time from the reception of the target tag ID to the start of the notification operation. Moreover, after the notification operation is started, the notification may be made considering the response delay time till the operator notices the notification and stops the movement of the reader 1, that is, the operator stops arm swinging.
In this variation, as shown in
The control executed by the CPU 4 of the reader 1 in this variation will be described referring to
The other configurations are the same as those in
In this variation configured as above, the total time including the predetermined response time th corresponding to an elapsed time from when the operator notices the notification till the operator stops the movement of the reader 1 in addition to the actual measured verification time tm and the predetermined notification time tc is used to calculate the detected position deviation. As a result, the notification in which deviation till the movement stop after the notification is corrected can be made, and notification with higher accuracy can be made. Also, by setting the predetermined response time th according to the notification type, detailed detected position deviation can be notified, and convenience for the operator can be improved.
(3) If a Notification Check Operation is Performed:
In this variation, an operating device, not shown, such as a check operation button is disposed in the operation part 7. After the reader 1 notifies that the target tag Tt has been detected, the operator inputs that the notification is checked into the reader 1 using the check operation button.
The control executed by the CPU 4 of the reader 1 in this variation will be described referring to
The other configurations are the same as those in
In this variation configured as above, the operator can input the intention that the notification by the display part 8 was checked through an operation of the check operation button. If this operation input is made, the calculation of the detected position deviation is stopped. As a result, continuation of the wasteful calculation of the detected position deviation or mode notification corresponding to that can be prevented.
(4) Others
In the above, as an example of a movable apparatus for communicating with an RFID tag, the reader 1 of the handheld type which makes search by being carried by the operator in the hand is described but not limited to that. That is, the present invention can be applied to an apparatus for communicating with an RFID tag disposed in various types of robot or various types of movable equipment such as a vehicle and a conveyer, for example, and moving linearly, in an arc-state, and in a circular motion, for example. In these cases, the same advantages as above are obtained.
Other than those described above, the methods of the above-described embodiment and the variations may be combined as appropriate for use.
Though not specifically exemplified, the present invention should be put into practice with various changes made in a range not departing from its gist.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2008-019677 | Jan 2008 | JP | national |
This is a CIP application PCT/JP2009/50519, filed Jan. 16, 2009, which was not published under PCT article 21(2) in English.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2009/050519 | Jan 2009 | US |
| Child | 12844325 | US |
