WO2007038348A1

WO2007038348A1 - A reliable dock-door system using radio frequency identification interrogators

Info

Publication number: WO2007038348A1
Application number: PCT/US2006/037115
Authority: WO
Inventors: Li-Cheng Zai; Sophia Liu; Xinyu Zang
Original assignee: ADTECH RFID Inc
Current assignee: ADTECH RFID Inc
Priority date: 2005-09-23
Filing date: 2006-09-22
Publication date: 2007-04-05
Anticipated expiration: 2008-03-23

Abstract

A loading dock door system using radio frequency identification (RFID) readers provides a reliable and efficient dock-door system and method. By using one or multiple portable RFID interrogators, in combination with one or more stationary RFID readers, exception conditions occurring at multiple loading dock doors can be efficiently and effectively handled. The RFID dock door system consists of at least one stationary and portable RFID readers, an audio visual alert device, and at least one control program running on a computing device. The control program monitors the tag data detected at the dock doors and compares them with data stored locally or on a backend information system. When an exception condition occurs, the control program sends a 'Exception' command to the audio and visual devices at the dock door and to the portable RFID reader. Instructions for resolving the exception condition can be displayed to a user on the display of either the stationary or portable RFID reader. If there is no exception condition, or if an exception condition has been cleared by a user, the control program can send a 'Complete' command to the audio visual devices indicating that no further action is necessary.

Description

A Reliable Dock-Door System Using Radio Frequency Identification

Interrogators

Cross-reference to Prior Applications

[0001] This application is the non-provisional version of and claims the priority date of Provisional Application No. US 60/720,156 with filing date of September, 23, 2005 which is incorporated herein by reference.

Background of the Invention Area of the Art

[0002] This invention relates generally to Radio Frequency Identification (RFID) systems and methods for inventory management and tracking, and, more particularly, to a reliable dock-door system using RFID interrogators.

Description of the Prior Art

[0003] Since the first demonstration of a modern RFID system in the early 1970s, the development of RFID systems have expanded tremendously. This significant development is not unwarranted, RFID systems provide an automatic method for authenticating or identifying an RFID tagged object or person.

[0004] To provide this functionality, all RFID systems operate under the same general principle. Data is transmitted from a mobile device, called a tag, to a reader, which receives the transmitted signal and sends it to a device for processing. Data transmitted from the tag may include information regarding the location of the tag or specifics of the tagged item, such as its identity, price, or transaction history.

[0005] Most modem RFID systems are passive, wherein the RFID tags store data on a digital memory chip, containing some form of non-volatile memory such as EEPROM, coupled to a transponder with no internal power supply. In a passive RFID system, an interrogator emits a radiofrequency signal that induces a small amount of current in the tag. This current is sufficient to activate the digital memory chip of the tag, which backscatters a response signal to a receiving antenna of the RFID system. A processor can then process the signal received from the RFID tag to read the data on the tag. In addition to reading data from the digital memory chip, the RFID system may also write data to the digital memory chip through the RFID interrogators.

[0006] The potential applications for RFID systems are broad, and RFID systems are already widely used in a variety of markets. Some of these markets include: inventory tracking, identification, such as in passports or implants, automated payment systems at subways, gas stations or stores, and access control systems in office buildings and other secured sites.

[0007] In the context of inventory tracking, RFlD systems may be used at a loading dock door to track goods entering or leaving the inventory of a store, or warehouse. A typical prior art dock door RFID system is shown in FIG. 1. As can be seen, the prior art RFID dock door system has a stationary RFID reader 11 coupled to a plurality of antennae 12, 13, 14, and 15. Multiple antennae are needed because the range of a response signal from a passive RFID tag is only two to three meters. As the RFID tagged item enters the area of the dock door, the RFID tag responds to the signal from an RFID interrogator. This response signal is received by one or more of the plurality of antennae and forwarded to the RFID reader. The RFID reader may include a processor to process the signal, or the RFID system may be tied directly to a computer that automatically updates the inventory record according to the signals received by the RFID system.

[0008] The main problem with prior art loading dock door RFID systems, however, is that the correct read rate of RFID tags is not 100%. As a result, tagged items may pass through the dock door either without being detected at all or without being correctly detected. Moreover, when there is an error (an "exception condition") at a prior art dock door system, or an event where there is some error with the tagged item or inventory tracking system, prior art dock door systems may require intensive manual operations to correct the problem.

Summary of the Invention

[0009] Therefore, it is an object of the current invention to overcome the aforementioned limitations of the prior art, and provide a method, and system to accurately, reliably and efficiently track inventory at a loading dock door. The current invention provides this functionality through a combination of stationary and portable RFID interrogators, audio visual alert devices, and at least one control program running on a computing device.

[0010] By using one or multiple portable RFID interrogators, in combination with one or more stationary RFID readers, exception conditions occurring at multiple loading dock doors can be efficiently and effectively handled. The stationary and/or portable RFID readers detect RFID data at a loading dock door and transmit this data to the control program running on the computing device. The control program monitors the tag data detected at the dock doors and compares them with already existing data stored locally or on a backend information system. When an exception condition occurs (e.g., the tag data do not agree with the stored data), the control program sends an "Exception" command to the audio and visual devices at the dock door and to the portable RFID reader. The audio visual devices indicate to a user that an exception condition has occurred, and provide instructions for resolving the exception condition. A user may then take the appropriate steps for resolving the condition, such as entering correct data, replacing a missing or malfunctioning RFID tag, or handling the item according to special handling instructions which can be displayed on the audio visual device (e.g., an LCD or CRT screen). Once the special conditions have been resolved, or if there is no exception condition, the control program can send a "Complete" command to the audio visual devices indicating that no further action is necessary. In this manner, RFID tagged items can be effectively tracked, processed and handled at the loading dock doors of a facility.

Description of the Figures

[0011] FIGURE 1 is an illustration of a prior art RFID dock door system.

[0012] FIGURE 2 is an illustration of one embodiment of an RFID dock door system as contemplated by the current invention.

[0013] FIGURE 3 is a hardware block diagram of an individual dock door within the inventive RFID dock door system.

[0014] FIGURE 4 is a sequence diagram for inventory tracking in one embodiment of the inventive dock door RFID system.

[0015] FIGURE 5 is a top view of a portable RFID interrogator of the inventive RFID dock door system.

[0016] FIGURE 6 is a sequence diagram for controlling the user interface of the portable RFID interrogator of the inventive RFID dock door system.

[0017] FIGURE 7 is a sequence diagram for controlling the user interface of the portable RFID interrogator of the inventive RFID dock door system.

[0018] FIGURE 8 is a sequence diagram for automatic association of a portable RFID interrogator with a dock door equipped with stationary RFID interrogators of the inventive RFID dock door system.

Detailed Description of the Invention

[0019] The following description is provided to enable any person skilled in the art to make and use the invention and sets forth the best modes contemplated by the inventor of carrying out their invention. The the current invention is directed to a dock door RFID system for tracking inventory and a method of using the system.

[0020] In one embodiment of the inventive RFID dock door system, depicted in FIG. 2, the RFID dock door system 20 may comprise a plurality of dock doors 21-1 to 21 -n. The RFID components of each dock door, described in reference to FIG. 3, are connected to a computing device 23 and wireless access point 24 via a network backbone 26. The computing device 23 processes signals from the RFID readers 31 within the RFID dock door system 20 to track inventory and store related data. The wireless access point 24 provides a connection between the network backbone 26 and a plurality of portable RFID readers 22-1 to 22-m.

[0021] By connecting a plurality of dock doors to the inventive RFID system, information regarding inventory or other tagged items can be tracked or processed over a building or complex. Moreover, the RFID dock door systems at different physical locations can be connected via the network backbone allowing a user to track inventory or tagged items at different physical locations. For instance, if the dock door RFID systems for manufacturing plants making a specific part, or in a specific region, were connected via the network backbone 26, a user coXild track inventory movement over a particular region, or for a specific part, product or process. This improved tracking capability allows a user to more effectively and efficiently manage the assets/inventory moving within their manufacturing or distribution system.

[0022] In an alternate embodiment of the inventive RFID dock door system, the components of the RFID dock door system, such as the RFID readers, wireless access points, and processing device, may be connected via data means other than a traditional network backbone. For instance, components of the RFID dock door system could be directly connected to one another, or connected via a bus, star, ring, mesh or bus-ring network. In addition, the connection between the components can also vary, including: serial connections, parallel connections, or wireless connections. By selecting one of these connection topologies and means, a user may tailor the RFID dock door system to the needs of a particular facility or function.

[0023] Moreover, the system may be comprised only of a single dock door having RFID components 30 connected to a computing device 23 and a wireless access point 24 via a network backbone 26, and at least one portable RFID reader connected to the network backbone 26 via a wireless connection.

[0024] To track inventory or tagged items in either of these embodiments of the inventive RFID dock door system, each tagged item can be given a unique identifier that corresponds to information relating to the item in a spreadsheet, table, or other data format usually populated by a back end information system (e.g., a Manufacturing Resource Planning (MRP) system). Upon receiving a signal corresponding to a unique identifier from the RFID reader 31 , the computing device 23 attempts to find the item specific data in the table or spreadsheet and update the data, depending on the signal received from the RFID reader 31, or send it to a different application, along with the processed RFID signal, for further processing.

[0025] A hardware block diagram for an individual RFID dock door 30 is depicted in FIG. 3. In this figure it can be seen that each dock door includes a plurality of antennae 32-35, an RFID reader 31, and one or more audio visual alert device(s) 36. The RFID reader 31 is a stationary reader positioned near the dock door. As a tagged item enters the area of the dock door, the antennae 32-35, pick up the backscattered signal from the RFID tag on the tagged item and send the signal to the RFID reader 31. The RFID reader can process the tag's signal to derive the unique identifier for the tagged item, or, alternatively, the RFID reader 31 can send the data to the computing device 23 across the network backbone 26. If there is a message that to be displayed to a person handling the tagged item at the dock door, such as an exception message or specific handling instructions, the audio visual alert device(s) 36 can alert the person that there is information regarding the tagged item and display the information. As will be discussed in reference to FIG. 4, a portable RFID reader 22 can then be associated with the stationary RFID reader 31 to clear the error message or otherwise indicate that the special handling instructions have been complied with.

[0026] FIGURE 4 diagrams one possible sequence followed by the RFID dock door system 20 while tracking or processing a tagged item. At 41, control software S1 running on at least one computing device 23 sends a command to at least one stationary reader 31 at a dock door indicating that it should read the RFID tag of a tagged item. If the dock door has more than one RFID reader 31, the control software may send a command to both RFID readers S2, S3 to ensure the tagged item is correctly processed. The stationary RFID reader(s) 31 read the RFID tag(s) of a tagged item, and send the data back to the control software S1 running on the at least one computing device 23 at step 42. The control software S1 then compares the data with information stored on a local table/spreadsheet (often from a back end information system) or sends the data to a back end information system for comparison. If the data received from the RFID tag matches the data stored on the system, and there are no special handling instructions, then the task is complete and the information stored on the table can be updated, can be used to route the tagged item, or in some cases no further action is be taken.

[0027] At step 43, if the data from the information system does not match the data from the tagged item, or if there are special handling instructions, a "Task Incomplete" event occurs, and the control software S1 sends an "Exception XYZ" command to the stationary RFID reader 31 and a portable RFID reader 22. Each reader then turns on the audio visual indicators based on the specific case represented by the label XYZ; it will be appreciated that the audio visual indicators can also be directly controlled by the control software S1 depending on the implementation of the inventive system. The person handling the tagged item is, in turn, alerted by the audio visual indicators on either the stationary reader 31 or the portable reader 22 of the "Task Incomplete" event.

[0028] Along with the exception command, the control software can send instructions for related to the "Task Incomplete" event, such as special handling instructions, to the audio visual indicators of the stationary or portable RFID readers. The person handling the tagged item may then read these instructions and resolve the "Task Incomplete" event, either by physically correcting the exception condition, following the handling instructions, or entering required information. In one embodiment, shown in step 44, the person handling the tagged item can actuate a trigger or button on the portable RFID reader 22 to resend the data corresponding to the tagged item, and indicate to the RFID dock door system 20 that the instructions for dealing with the "Task Incomplete" event have been followed. If the "Task Incomplete" event is resolved by the user's actions, as shown at step 45, the control software S1 analyzes the newly collected data and sends a "Complete" command to the stationary and portable RFID readers 22, 31. A "Task Complete" message, or other indication that the "Task Incomplete" event has been resolved, is then displayed on the audio visual indicators of the stationary and portable RFID readers.

[0029] There can be a number of different reasons that the data from the information system might not match the data measured from the tagged item. There are two major causes of error. In the first place the might be a human error in which a given item that the information system "thinks" is present in a shipment either is not present (accidentally omitted) or is present but is either labeled with no RFlD tag or with an incorrect RFID tag. The other source of error is a reading error in which the expected item is present but either the RFID tag does not emit a detectable signal (might be due to antenna position) or the detectable signal is misread by the system. The process can be visualized if one considers the situation of a palletized assembly of parts. The pallet has an RFID tag and each part in the assembly also contains a unique RFID tag. When the pallet RFID tag is detected, the correct individual tags should also be detected. However, due the possible errors just mentioned, the correct combination of individual tags may not be detected. In that case human intervention is required. For example, the portable reader 22 can be used to directly interrogate the pallet tag (if one can be found — if the tag is missing, it can be manually replaced, thereby correcting the error). If direct interrogation does not yield the expected pallet tag data, there may be an erroneous placement of pallet RFID tags. If the pallet tag is correct, then each part of the assembly can be inspected to ensure the presence of an RFID tag and that tag can be interrogated to verify that it produces the correct data. Missing or incorrect tags can be replaced or the entire pallet can be sent to another department for correction.

[0030] In one embodiment, a portable RFID reader 22 takes the form of a hand-held device as shown in FiG. 5. The top panel of the portable RFID reader 22 includes a LED section 51, a display section 52 and a keypad section 53. The LED section 51 may include LEDs corresponding to specific events, such as an okay (OK) LED 51-1, a message (MSG) LED 51-2, and a task (TASK) LED 51-3. These LEDs may indicate a specific task state to the handler of a tagged item. The display section 52 can display messages or instructions regarding a specific task state, and the user may enter information corresponding to a specific task state via the keypad 53.

[0031] FIGURE 6 depicts a sequence for controlling the okay 51-1 and task 51-3 LEDs of a portable RFID reader 22. At step 61 , when one or multiple exception conditions occur, the control software S1 sends the "Exception XYZ" command to the portable RFID reader 22. In response, the task LED 51-3 of the portable RFID reader 22 lights up, indicating a task state, and information regarding the specific exception condition is displayed on the display 52 of the portable RFID reader 22. At step 62, a user physically clears the exception conditions, if necessary, and actuates the trigger of the portable reader to collect new data from the tagged item. At step 63 the control software S1 detects that a task is in process after receiving new tag data, and sends an "In Progress" command to be displayed on the display 52 of the portable RFID reader 22. At step 64, if the exception conditions are cleared, the control software S1 analyzes the newly collected data and sends a "Complete" command to be displayed on the display 52 of the portable RFID reader 22. In addition, the okay 51-1 LED may also be actuated providing further indication that the exception conditions have been resolved. [0032] In typical RFID applications, there are many interactive activities between a user and the control software S1 of an RFID dock door system 20. For example, the control software S1 can tell the user to look for missing pallet tags instead of regular item tags, or provide other specialized handling instructions. In one embodiment, the dock door system can use several classes of messages to effectively communication between the user and the control software S1. One class of message can be a temporary message that stays on the display 52 for a short period of time and is typically used for instructional use, such as "look for pallet tag" and "pull trigger". A second class of message is a persistent message, that remains on the display 52 indefinitely until the operator acknowledges and clears it. Messages for a new task list or exception job handling typically fall under the persistent class of messages.

[0033] FIGURE 7 shows a sequence diagram for controlling the Message LED 51-2 of the portable RFID reader 22. At step 71, control software S1 sends a "Temporary MSG" command to the portable RFID reader 22 that controls the message LED 51-2 and display 52 of the portable RFID reader. Alerted by the message LED 51-2, the user then reads the temporary message on the display. In one embodiment, the "Temporary MSG" command may also trigger an audio cue to alert a user to a message. At 72, the control software S1 sends a "Persistent MSG" command to the portable RFID reader 22 that controls the message LED 51-2 and the portable RFID reader's display 52. As with a temporary message, the user is alerted by the message LED 51-2 that a message has been sent, and can read the message on the display 52 of the portable RFID reader 22. At 73, the operator presses a MSG key to view and clear a message received from the control software. If there is no "Temporary" or "Persistent" message from the control software S1, the control software S1 sends the portable RFID reader 22 a "No MSG" command to the reader 22 that controls the message LED 51-2 and display.

[0034] As previously mentioned, the inventive RFID dock door system 20 includes at least one portable RFID reader 22. Because one embodiment of the RFID dock door system includes a plurality of dock doors, a given portable RFID reader must be able to associate itself with a number of different the stationary RFID readers 31 at a particular dock door 21 -n within the RFID dock door system 20. The portable RFID reader S5 may associate with the stationary RFID readers S2, S3 of a particular dock door, as shown in FIG. 8, through a program on the control software S1, or, by accessing the network backbone 26 through a wireless access point at a particular dock door within the RFID dock door system 20. [0035] In one embodiment, as shown at step 84 of FIG. 8, the portable RFID reader S5 associates with stationary RFID readers S2, S3 after sending data regarding an RFID tagged object to the control software S1. The control software S1 compares the tag data sent from the portable RFID reader S5 with tag data sent from stationary RFID readers S2 to SN, and, when there is a match, the control software S1 associates the portable RFID reader S5 with the stationary RFID reader(s) S2, S3 that sent the matching tag data.

[0036] Figure 8 depicts a sequence diagram for the automatic association of a portable RFID reader 22 with a stationary RFID reader 31 at a dock door 21 -n. At step 81 , control software S1 sends "Read Tag" commands to a first stationary reader S2 and a second stationary reader S3, so that the two readers start to read the RFID tags of a tagged item. At step 82, both the first stationary RFID reader S2 and the second stationary RFID reader S3 send the collected tag data back to the control software S1, which compares the collected data with data stored locally on the computing device 23, or on some other back end information system. Depending on the results of the comparison, data corresponding to the tagged item may be updated, the tagged item may be cleared, or there may be an indication to the user that further action is required.

[0037] If further action is required, as shown in step 83, a "Task Incomplete" event occurs, and the control software S1 sends an "Exception XYZ" command to the stationary RFID readers S2, S3, and any portable RFID readers S5 associated with the particular dock door. Each reader, S2, S3, S5, then turns on their audio visual indicators to alert the user to the exception event. At step 84, the user reads the instructions sent by the control software S1, and, if necessary, takes further action to clear the exception event. As described above, the portable RFID reader S5 can associate with the stationary RFID readers S2, S3 at this point if it has not already. Once the exception event is cleared, the user can pull the trigger of the portable RFID reader 22 to send a new data set regarding the tagged item to the control software S1. At 85, the control software S1 determines that no further action is required, and, at 86, the control software S1 sends a "Complete" command to the RFID readers S2, S3, and S5, indicating to the user that no further action is required. The portable RFID reader S5 can then disassociate itself from the RFID readers at that particular dock door.

[0038] A portable RFID reader 22 can associate itself with a particular dock door by simply reading an RFID tag of a already correctly read (by the stationary RFID readers) tagged item at the dock door. When the portable RFID reader S5 sends the data regarding the tagged item to the control software S1, the control software compares the data with the correct data already sent from stationary RFID readers S2, S3 and, if the data match, associates the portable RFID reader S5 with those stationary RFID readers S2 and S3. By automatically associating a portable RFID reader with a particular dock door, a single portable RFID reader 22 can be used to receive and clear exception conditions for a tagged item at multiple dock doors.

[0039] The following claims are thus to be understood to include what is specifically illustrated and described above, what is conceptually equivalent, what can be obviously substituted and also what essentially incorporates the essential idea of the invention. Those skilled in the art will appreciate that various adaptations and modifications of the just-described preferred embodiment can be configured without departing from the scope of the invention. For instance, many of the steps in the method described above, or modules in the inventive system, may be combined or reordered. For that reason, the illustrated embodiment has been set forth only for the purposes of example and should not be taken as limiting the invention. Therefore, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described herein.

Claims

I claim:

1. A radio frequency identification loading dock door system comprising: at least one loading dock door; data means for providing data interconnectivity at least one stationary radio frequency identification reader capable of connection to the data means and capable of reading a signal from a radio frequency identification tag; at least one portable radio frequency identification reader capable of connection to the data means and capable of reading a signal from a radio frequency identification tag; at least one alert indicator capable of connection to the data means; and at least one computing device capable of connection to the data means and running a software program.

2. The radio frequency loading dock door system of claim 1, wherein the data means comprises a network backbone for connecting the stationary radio frequency identification reader and the computing device.

3. The radio frequency loading dock door system of claim 1, further comprising at least one antenna coupled to the stationary radio frequency identification reader.

4. The radio frequency loading dock door system of claim 1, wherein the software program includes a function to compare data from a radio frequency identification tag with already existing data regarding the identification tag.

5. The radio frequency loading dock door system of claim 1, wherein the data means further comprises a wireless access point.

6. The radio frequency loading dock door system of claim 5, wherein the data means further comprises: a network backbone connecting the stationary radio frequency identification reader and the computing device, wherein the portable radio frequency reader can be connected to the computing device by means of the wireless access point.

7. The radio frequency loading dock door system of claim 1, wherein the stationary and portable radio frequency readers include an alert indicator selected from the group consisting of light emitting diodes, video displays and audio displays.

8. The radio frequency loading dock door system of claim 6, wherein the portable radio frequency reader can become associated with a stationary radio frequency reader.

9. The radio frequency loading dock door system of claim 1, wherein the software program controls at least one of the portable radio frequency reader, the stationary radio frequency reader and the alert indicator.

10. A radio frequency identification loading dock door system comprising: at least one loading dock door; at least one stationary radio frequency identification reader capable of reading a signal from a radio frequency identification tag; at least one portable radio frequency identification reader capable of reading a signal from a radio frequency identification tag; at least one alert indicator; at least one computing device running a software program that controls the stationary and portable radio frequency identification readers; and a network backbone connecting at least one stationary radio frequency identification reader to at least one computing device.

11. The radio frequency loading dock door system of claim 10, further comprising a wireless access point.

12. The radio frequency loading dock door system of claim 10, wherein the portable radio frequency identification reader can be connected to the network backbone through the wireless access point.

13. The radio frequency loading dock door system of claim 12, wherein the portable radio frequency identification reader can become associated with at least one stationary radio frequency identification reader.

14. The radio frequency loading dock door system of claim 10, wherein the stationary and portable radio frequency readers include an alert indicator selected from the group consisting of light emitting diodes, video displays and audio displays.

15. The radio frequency loading dock door system of claim 10, wherein the software program includes a function to compare data from a radio frequency identification tag with already existing data regarding the identification tag.

16. The radio frequency loading dock door system of claim 10, further comprising at least one antenna coupled to the radio frequency identification reader.

17. A method of using a loading dock door radio frequency identification system to identify and track radio frequency tagged items, comprising the steps of: reading radio frequency identification data from a radio frequency tagged item; analyzing the radio frequency identification data with a software control program running on a computing device; and receiving an indication from the software control program regarding the radio frequency tagged item.

18. The method of claim 17, wherein the step of analyzing includes a comparing data received from a radio frequency identification tag with already existing data regarding the identification tag.

19. The method of claim 17, wherein the step of reading the radio frequency identification data from a radio frequency tagged item is performed by at least one stationary radio frequency identification reader.

20. The method of claim 17, further comprising a step of displaying the indication received from the software control program.

21. The method of claim 20, further comprising a step of alerting a user that an indication has been received from the software control program.

22. The method of claim 15, further comprising the step of a user taking action based on the indication received from the software control program.

23. The method of claim 17, wherein the steps of reading the radio frequency identification data and receiving the indication from the software control program are performed by a stationary radio frequency identification reader or by a portable radio frequency identification reader.