RFID conveyor system and method

• US 20060244611A1
• Filed: 03/23/2006
• Published: 11/02/2006
• Est. Priority Date: 03/29/2005
• Status: Active Grant

• Current Assignee: Datalogic Automation Incorporated (Datalogic S.p.A.)
• Original Assignee: Accu-Sort Systems Incorporated (Datalogic S.p.A.)
• Inventors: Cox, James N.
• Granted Patent: US 7,545,273 B2
• Time in Patent Office: Days
• US Class Current: 340/572.700
• CPC Class Codes: B07C 5/3412 according to a code applied to the object which indicates a property of the object, e.g. quality class, contents or incorrect indication sorting according to size measured by light-responsive means B07C5/10; sorting according to optical properties B07C5/342; for packages B65D79/02; for information carriers G06K7/00
• CPC Class Codes: B65G 2203/042 Sensors
• CPC Class Codes: G06K 17/00 Methods or arrangements for effecting co-operative working between equipments covered by two or more of main groups G06K1/00 - G06K15/00, e.g. automatic card files incorporating conveying and reading operations
• CPC Class Codes: G06K 2207/1012 Special detection of object
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10079 the collision being resolved in the spatial domain, e.g. temporary shields for blindfolding the interrogator in specific directions
• CPC Class Codes: G06K 7/10316 using at least one antenna particularly designed for interrogating the wireless record carriers antennas in general H01Q1/22
• CPC Class Codes: G06K 7/10336 the antenna being of the near field type, inductive coil
• CPC Class Codes: G06K 7/10346 the antenna being of the far field type, e.g. HF types or dipoles
• CPC Class Codes: G06K 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas
• CPC Class Codes: G06K 7/10435 the interrogation device being positioned close to a conveyor belt or the like on which moving record carriers are passing conveying in accordance with bodily destination marks, see B65G47/46, sorting of objects carrying identity markings, see B07C5/34
• CPC Class Codes: G06Q 10/08 Logistics, e.g. warehousing, loading or distribution; Inventory or stock management
• CPC Class Codes: H01Q 1/2208 associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems methods or arrangements for sensing record carriers, e.g. for reading patterns G06K7/00; record carrier for use with machines and with at least a part designed to carry digital markings G06K19/00
• CPC Class Codes: H01Q 1/2216 used in interrogator/reader equipment
• CPC Class Codes: H01Q 1/2241 used in or for vehicle tyres
• CPC Class Codes: H01Q 17/001 for modifying the directional characteristic of an aerial
• CPC Class Codes: H01Q 21/065 Patch antenna array
• CPC Class Codes: H01Q 21/08 the units being spaced along or adjacent to a rectilinear path waveguide fed H01Q21/0037
• CPC Class Codes: H01Q 21/28 Combinations of substantially independent non-interacting antenna units or systems multiple beam H01Q25/00
• CPC Class Codes: H01Q 9/0407 Substantially flat resonant element parallel to ground plane, e.g. patch antenna dipole H01Q9/285; monopole H01Q9/40
• CPC Class Codes: H01Q 9/0428 : radiating a circular polarised wave

Abstract

A conveyor system for processing items on which radio frequency identification tags are disposed comprises a frame and a conveyor that is disposed moveably on the frame and that conveys items through a path of travel, each item having at least one respective radio frequency identification tag disposed thereon. At least one antenna is disposed proximate the path of travel so that the antenna radiates radio frequency signals into a first area through which the items pass and receives responses to the radio frequency signals from radio frequency identification tags on the items passing through the path of travel. A radio frequency transmitter drives the antenna. A radio frequency receiver receives the signals corresponding to the responses and outputs the first signals corresponding to the responses. A processor receives the first signals from the receiver and is programmed to associate a first signal with a first item if the processor receives the first signal from the receiver while at least a portion of the first item is within a predefined second area that includes at least part of the first area. The processor is programmed to define a length of the second area with respect to the path of travel based on a distance between the first item and a second item next following the first item in the path of travel.

Claims

1. A conveyor system for processing items on which radio frequency identification tags are disposed, said system comprising:

a frame;

a conveyor that is disposed movably on the frame and that conveys items through a path of travel, each item having at least one respective radio frequency identification tag disposed thereon;

at least one antenna disposed proximate the path of travel so that the at least one antenna

radiates radio frequency signals into a first area through which the items pass and

receives responses to the radio frequency signals from radio frequency identification tags on the items passing through the path of travel;

a radio frequency transmitter that drives the antenna to emit the radio frequency signals into the first area;

a radio frequency receiver that receives signals from the antenna corresponding to the responses received by the antenna from the respective radio frequency identification tags and outputs first signals corresponding to the responses; and

a processor that receives the first signals from the receiver,

wherein the processor is programmed to

associate a said first signal with a first said item if the processor receives the first signal from the receiver while at least a portion of the first item is within a predefined second area that includes at least part of the first area, and

define a length of the second area with respect to the path of travel based on a distance between the first item and a second item next following the first item in the path of travel.

2. The system as in claim 1, including a plurality of said antennas.

3. The system as in claim 2, wherein each said antenna both radiates the radio frequency signals and receives the responses.

4. The system as in claim 1, wherein each said response includes information that identifies the radio frequency identification tag from which said response is received, wherein each first signal includes the information in its corresponding response, and wherein the processor is programmed to associate the information included in the signal with the first item if the processor receives the first signal while at least a portion of the first item is within the second area.

5. The system as in claim 1, including a detector disposed with respect to the path of travel so that second signals output by the detector indicate presence of the items at a first position in the path of travel upstream from the second area, wherein the processor receives the second signals from the detector and is programmed to track, responsive to the second signals, each said item with respect to a second area, when said item is between the first position and the second area.

6. The system as in claim 1, wherein the processor is programmed to maintain a default value for the length for the second area and, if a length of the first item plus the distance is less than the default value, redefine the length of the second area from the default value to a new value less than the length of the first item plus the distance.

7. The system as in claim 6, wherein the new value is equal to the length of the first item plus a predetermined portion of the distance.

8. The system as in claim 7, wherein the predetermined portion is one-half.

9. The system as in claim 6, wherein the predetermined portion is variable, depending on the distance.

10. A conveyor system for processing items on which radio frequency identification tags are disposed, said system comprising:

a frame;

a generally planar belt that is disposed movably on the frame and that conveys items through a path of travel, each item having at least one respective radio frequency identification tag disposed thereon;

at least one antenna disposed proximate the belt so that the antenna

radiates radio frequency signals into a first area that is proximate the belt and through which the items pass and

receives responses to the radio frequency signals from the respective radio frequency identification tags on the items on the belt;

a radio frequency transmitter that drives the antenna to emit the radio frequency signals into the first area;

a radio frequency receiver that receives signals from the antenna corresponding to the responses received by the antenna from the respective radio frequency identification tags and outputs first signals corresponding to the responses;

a detector disposed with respect to the belt so that second signals output by the detector indicate presence of the items on the belt at a first position in the path of travel; and

a processor that controls the transmitter to drive the antenna and that receives the first signals from the receiver and the second signals from the detector,

wherein the processor is programmed to

responsive to the second signals, track each said item with respect to a predefined second area that is downstream from the first position with respect to the path of travel and that includes at least a portion of the first area,

associate a said first signal with a first said item if the processor receives said first signal from the receiver during a period in which at least a portion of the first item is within the second area,

responsive to the second signals, determine a distance between the first item and a second item next following the first item on the belt with respect to the path of travel, and

based on the distance, define a length of the second area with respect to the path of travel.

11. The system as in claim 10, wherein each said response includes information that identifies the radio frequency identification tag from which said response is received, wherein each first signal includes the information in its corresponding response, and wherein the processor is programmed to associate the information included in the signal with the first item if the processor receives the first signal while at least a portion of the first item is within the second area.

12. The system as in claim 10, wherein the processor is programmed to maintain a default value for the length for the second area and, if a length of the first item plus the distance is less than the default value, redefine the length of the second area from the default value to a new value less than the length of the first item plus the distance.

13. The system as in claim 12, wherein the new value is equal to the length of the first item plus a predetermined portion of the distance.

14. The system as in claim 13, wherein the predetermined portion is one-half.

15. The system as in claim 13, wherein the predetermined portion is variable, depending on the distance.

16. A conveyor system for processing items on which radio frequency identification tags are disposed, said system comprising:

a frame;

a generally planar belt that is disposed movably on the frame and that conveys items through a path of travel, each item having at least one respective radio frequency identification tag disposed thereon;

at least one antenna disposed proximate the belt so that the antenna

radiates radio frequency signals into a first area that is proximate the belt and through which the items pass and

receives responses to the radio frequency signals from radio frequency identification tags on the items on the belt, wherein each response includes information that identifies the respective radio frequency identification tag from which said response is received;

a radio frequency transmitter that drives the antenna to emit the radio frequency signals into the first area;

a radio frequency receiver that receives signals from the antenna corresponding to the responses received by the antenna from the respective radio frequency identification tags and outputs first signals corresponding to the responses and including the information;

a detector disposed with respect to the belt so that second signals output by the detector indicate presence of the items on the belt at a first position in the path of travel; and

a processor that controls the transmitter to drive the antenna and that receives the first signals from the receiver and the second signals from the detector,

wherein the processor is programmed to

responsive to the second signals, track each said item with respect to a predefined second area that is downstream from the first position with respect to the path of travel and that includes at least a portion of the first area,

associate said information included in a said first signal with a first said item if the processor receives said first signal from the receiver during a period in which at least a portion of the first item is within the second area,

responsive to the second signals, determine a length of the first item and a distance between the first item and a second item next following the first item on the belt with respect to the path of travel, and

if the length of the first item plus the distance is less than a predetermined default value, define a length of the second area with respect to the path of travel to be equal to the length of the first item plus a predetermined portion of the distance.

17. The system as in claim 16, wherein the predetermined portion is one-half.

18. The system as in claim 16, wherein the predetermined portion is variable, depending on the distance.

19. A method of processing items on each of which at least one respective radio frequency identification tag is disposed, where the items are conveyed through a path of travel by a conveyor movably disposed on a frame, said method comprising the steps of:

radiating radio frequency signals into a first area through which the items pass in the path of travel;

receiving responses to the radio frequency signals from radio frequency identification tags on the items in the path of travel and outputting first signals corresponding to the responses;

detecting presence of the items on the conveyor at a first position in the path of travel;

tracking each said item with respect to a predefined second area that is downstream from the first position with respect to the path of travel and that includes at least a portion of the first area;

associating a said first signal with a first said item if the response corresponding to the first signal is received during a period in which at least a portion of the first item is within the second area;

based on presence of the first item detected in the detecting step, determining a distance between the first item and a second item next following the first item on the conveyor with respect to the path of travel; and

based on the distance, defining a length of the second area with respect to the path of travel.

20. The method as in claim 19, including maintaining a default value for the length of the second area and, if a length of the first item plus the distance is less than the default value, the defining step includes redefining the length of the second area from the default value to a new value less than the length of the first item plus the distance.

21. The method as in claim 20, wherein the new value is equal to the length of the first item plus a predetermined portion of the distance.

22. The system as in claim 21, wherein the predetermined portion is one-half.

23. The system as in claim 21, wherein the predetermined portion is variable, depending on the distance.