Object tracking and management system and method using radio-frequency identification tags

• US 6,600,418 B2
• Filed: 12/12/2000
• Issued: 07/29/2003
• Est. Priority Date: 12/12/2000
• Status: Expired due to Term

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: McGee, James P., Sainati, Robert A., Sheehan, Jr., Richard L., Tong, Sai-Kit K., Francis, Robert C.
• Primary Examiner(s): MULLEN, THOMAS J
• Application Number:
  US09/735,243
• Publication Number:
  US 20020070862A1
• Time in Patent Office: 959 Days
• Field of Search: 340/572.1, 340/505, 340/10.1, 340/5.92, 340/988, 235/385, 705/22, 705/28, 700/213, 700/214, 700/215, 700/216, 700/217, 700/225, 700/226, 700/228, 700/229
• US Class Current: 340/572.1
• 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: G06Q 10/087 Inventory or stock management, e.g. order filling, procurement or balancing against orders

Abstract

An object tracking and management system and method using radio-frequency identification (“RFID”) tags is disclosed. Objects to be moved between locations are outfitted with RFID tags having information relating to the identities of the objects. The locations are also marked by RFID tags containing information on the locations. A transport vehicle for moving the objects is equipped with an RFID interrogator capable of detecting signals from the RFID tags. An onboard processor provides the operator of the vehicle with instructions on the movement of objects. The processor also determines the identities of the objects and locations from the detected signals and provides the operator with feedback as to the identity of an object being moved, the location of the vehicle and any error in carrying out the instructions. Numerous variations of the basic system and method using RFID tags are also described.

Claims

1. A system for tracking an object positionable at a plurality of locations, the system comprising:

(a) a transport vehicle to move the object between locations;

(b) an object marker associated with the object which stores information indicative of the identity of the object;

(c) a plurality of location markers, each of which is positioned at one of a plurality of locations and stores information indicative of the location of the marker;

(d) an interrogator mounted on the vehicle to receive from the object marker the information indicative of the identity of the object and from the location markers the intonation indicative of the location of the markers, the interrogator comprising a radio-frequency transmitter for transmitting information to be stored on a marker and a radio-frequency receiver; and

(e) a processor on-board the vehicle and operatively connected to the interrogator, wherein the processor determines the identity of the object from the information indicative of the identity of the object, the location of at least one of the location markers from the information indicative of the location of the marker, and the spatial relationship between the object and the location.

2. The system of claim 1, wherein the radio-frequency transmitter transmits one or more interrogation signals;

wherein each of the location markers comprises a radio-frequency identification tag to transmit a signal encoded with the information indicative of the location of the marker in response to one of the one or more interrogation signals;

wherein the object marker comprises a radio-frequency identification tag to transmit a signal encoded with the information indicative of the identity of the object in response to one of the one or more interrogation signals; and

wherein the radio-frequency receiver receives the signals from the location markers and object markers.

3. The system of claim 2, wherein the transmitter of the interrogator is further capable of transmitting a signal encoded with information and the object marker stores the encoded information.

4. The system of claim 2, wherein the interrogator further comprises a plurality of antennas to receive radio-frequency signals from a plurality of directions.

5. The system of claim 2, wherein the interrogator receives signals from a radio-frequency identification tag and generates a signal indicative of the distance between the interrogator and the tag.

6. The system of claim 5, wherein the interrogator varies the power level of the interrogation signal based on the distance between the interrogator and the tag.

7. The system of claim 5, wherein the interrogator generates a visual signal indicative of the distance between the interrogator and the tag.

8. The system of claim 2, wherein at least one of the location markers defines a plane, wherein the at least one of the location markers transmits a first signal indicating that the interrogator is located on one side of the plane and transmits a second signal indicating that the interrogator is located on the other side of the plane, and

wherein the second signal is different from the first signal.

9. The system of claim 8, wherein the at least one of the location markers comprises two radio-frequency identification tags defining the plane therebetween to transmit signals indicative of the location in response to an interrogation signal of sufficient strength from the interrogator, and wherein the at least one location marker is configured and arranged to enable the tag on the same side of the interrogator to respond to the interrogation signal while preventing the other tag from responding to the interrogation signal.

10. The system of claim 9, wherein the at least one location marker further comprises a radio-frequency shield positioned between the two tags.

11. The system of claim 10, wherein the shield comprises a metal plate.

12. The system of claim 2, wherein the transport vehicle further comprises a lift capable of retrieving and positioning an object at a plurality of heights and a height sensor for measuring the height at which the object is positioned, and wherein the processor is operatively connected to the height sensor to determine the height at which the object is positioned.

13. The system of claim 2, wherein the transmitter of the interrogator is further capable of transmitting a signal encoded with information and at least one of the location markers stores the encoded information.

14. The system of claim 1, wherein each of the location markers comprises a radio-frequency identification tag to transmit a signal encoded with the information indicative of the location of the marker;

wherein the object marker comprises a barcode containing the information indicative of the identity of the object;

wherein the radio-frequency transmitter transmits an interrogation signal and the receiver receives the encoded signals; and

wherein the interrogator further comprises a barcode reader that reads the barcode.

15. The system of claim 1, further comprising a signal generator operatively connected to the processor to provide to the operator of the vehicle a signal indicative of the location of one of the plurality of location markers when the interrogator receives from the location marker the information indicative of the location of the marker.

16. The system of claim 15, wherein the signal provided to the operator is an audible signal.

17. The system of claim 15, wherein the signal provided to the operator is a visual signal.

18. The system of claim 17, further comprising a computer display monitor, wherein the visual signal is a computer-generated pattern displayed on the monitor.

19. The system of claim 18, wherein the processor displays on the monitor instructions to the operator, the instructions including the identity of the object to be transported and at least one location to which the object is to be transported.

20. The system of claim 1, further comprising an additional interrogator mounted on the vehicle to receive from the object marker the information indicative of the identity of the object and from the location markers the information indicative of the location of the markers.

21. A system for tracking an object positionable at a plurality of locations on a traffic-bearing surface, the system comprising:

(a) a transport vehicle to move the object between locations;

(b) an object marker associated with the object which stores information indicative of the identity of the object;

(c) a strip of magnetic tape associated with the traffic-bearing surface, wherein the magnetic tape includes a plurality of segments, wherein each of the segments is encoded with information indicative of the location of the segment and each of the segments produces a magnetic signal encoded with the information indicative of the location of the segment;

(d) an interrogator mounted on the vehicle to receive from the object marker the information indicative of the identity of the object;

(e) a magnetic signal reader mounted on the vehicle for sensing the signals generated by the magnetic tape; and

(f) a processor operatively connected to the interrogator and the magnetic signal reader to determine the identity of the object from the information indicative of the identity of the object, the location of at least one of the segments of the magnetic tape and the spatial relationship between the object and the location.

22. A method of managing an object to be moved between locations in an environment wherein a first radio-frequency identification tag is affixed to the object and has stored therein and is capable of transmitting signals encoded with information indicative of the identity of the object, a second radio-frequency identification tag is affixed at a location and has stored therein and is capable of transmitting signals encoded with information indicative of the location of the second tag, and a transport vehicle is equipped with a radio-frequency identification tag interrogator, capable of receiving the signals from the tags and determining the information stored in the tags, the method comprising:

(a) using the interrogator to receive the information indicative of the identity of the object;

(b) determining a proposed location to which the object is to be moved;

(c) using the vehicle to move the object to a location;

(d) using the interrogator to receive the information indicative of the location; and

(e) depositing the object at the location when the location indicated by the information received in step (d) matches the proposed location.

23. The method of claim 22, further comprising the step of determining a proposed identity of the object, wherein the step (c) is performed only when the identity indicated by the information received in step (a) matches the proposed identity of the object.

24. The method of claim 22, further comprising providing an operator operating the transport vehicle with visual displays of instructions including the proposed identity of the object and proposed location.

25. The method of claim 24, wherein providing visual display comprises displaying the instructions on a computer screen.

26. The method of claim 25, wherein displaying on a computer screen comprises displaying through a graphical user interface.