Wireless call tag based material replenishment system

• US 6,317,082 B1
• Filed: 02/14/2000
• Issued: 11/13/2001
• Est. Priority Date: 02/12/1999
• Status: Expired due to Term

• Current Assignee: Zebra Technologies Corporation
• Original Assignee: Wherenet Corporation (Zebra Technologies Corporation)
• Inventors: Johnson, Walter S., Bacon, Thomas M., Hang, Huong M.
• Primary Examiner(s): Issing, Gregory C.
• Application Number:
  US09/503,675
• Time in Patent Office: 638 Days
• Field of Search: 700/115, 700/116, 700/179, 700/214, 700/215, 700/222, 235/385, 705/28, 342/387, 342/465, 342/450, 340/680, 340/679, 340/10.42, 340/825.49
• US Class Current: 342/465
• CPC Class Codes: G01S 13/74 Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems

Abstract

A call tag-based material replenishment system employs a tagged object radio location infrastructure of the type described in the U.S. Pat. No. 5,920,287. For each different part used by a lineside workstation an associated ‘call’ tag is placed at or near that workstation. To initiate replenishment of a part, a ‘call’ push-button on a call tag is operated. In response to the operation of the call button, an RF signal burst containing tag identity and status data is transmitted from the call tag. This information is recovered by a spatially distributed reader and processor subsystem for application to an asset management database. The database associates the call tag'"'"'s identification data with a particular part, to enable a resource management operator to specify what component is to be accessed from storage and delivered to the requesting call tag'"'"'s workstation.

Claims

1. For use with a system for producing an item from a plurality of different components, which are retrieved from storage remote with respect to workstations of said system and delivered to said workstations for use thereby in production of said item, a method of controlling replenishment of components employed by a respective workstation comprising the steps of:

(a) providing, at said respective workstation, a wireless transmitter device which is operative, in response to a stimulus applied thereto associated with the need for replenishment of a component, to controllably transmit a signal encoded with information representative of the identification of said wireless transmitter device;

(b) detecting, by at least one transmission reader, said signal transmitted by said wireless transmitter device;

(c) processing said signal as detected by said at least one transmission reader to identify said wireless transmitter device;

(d) accessing a computer storage containing information that associates said wireless transmitter device with a component employed by said respective workstation, based upon said information representative of the identification of said wireless transmitter device identified in step (c), so as to determine what component is to be replenished at said respective workstation, wherein said respective workstation uses different components in production of said item, and wherein step (a) comprises providing a respective wireless transmitter device for each of said different components, said respective wireless transmitter device being operative, in response to a stimulus applied thereto, to controllably transmit a signal encoded with information representative of the identification of said respective wireless transmitter device, and wherein said computer storage stores information that associates a respective wireless transmitter device with said respective workstation and a respective one said different components.

2. A method according to claim 1, wherein said wireless transmitter device is further operative to provide an indication of the transmission of said signal.

3. A method according to claim 1, wherein step (c) comprises processing said signal as detected at a plurality of spatially separated transmission readers to locate said wireless transmitter device.

4. A method according to claim 3, wherein step (c) further comprises processing signals detected at said plurality of said spatially separated transmission readers to determine which signals received by said plurality of transmission readers are first-to-arrive signals as transmitted from said wireless transmitter device, and conducting time-of-arrival differentiation of said first-to-arrive signals to locate said wireless transmitter device in said production system.

5. A method according to claim 1, wherein said wireless transmitter device is operative to repetitively transmit said signal in response to the application of said stimulus.

6. A method according to claim 1, wherein said wireless transmitter device is operative to randomly and repetitively transmit a signal irrespective of said stimulus that is encoded with the identification of the wireless transmitter to enable periodic and updated location of the wireless transmitter.

7. A method according to claim 1, wherein said wireless transmitter device includes memory which stores a multibit word representative of the identification of said wireless transmitter device, and is further operative to repetitively transmit a spread spectrum signal encoded with said information representative of the identification of said wireless transmitter device.

8. A method according to claim 3, wherein step (c) comprises processing signals detected at said readers by means of matched filter correlators, each having a plurality of matched filter banks containing parallel correlators which are operative to correlate a received signal with successively time offset versions of a reference pseudo random spreading code corresponding to that of spread spectrum signals transmitted by said wireless transmitter device.

9. For use with a manufacturing facility for producing an item from a plurality of different components, which are retrieved from storage remote with respect to workstations of said facility and delivered to said workstations for use thereby in production of said item, a system for controlling replenishment of components employed by said workstations comprising:

at or in proximity of each of said workstations, at least one wireless transmitter device, which is operative, in response to a stimulus applied thereto associated with the need for replenishment of a respective component used by said each workstation, to controllably transmit a signal encoded with information representative of the identification of said each wireless transmitter device;

at least one transmission reader that is operative to detect said signal transmitted by said each wireless transmitter device;

a processing subsystem, which is operative to process said signal as detected by said at least one transmission reader so as to identify said each wireless transmitter device;

a computer storage containing information that associates respective ones of said wireless transmitter devices with respective ones of said plurality of different components and workstations associated therewith, and being operative, in response to said information representative of the wireless transmitter device identified by said processing subsystem, to indicate what component is to be replenished at said each workstation, wherein one of said workstations uses different components in production of said item, and wherein a respectively different wireless transmitter device is provided at said one workstation for each of said different components, said respectively different wireless transmitter device being operative to controllably transmit a signal encoded with information representative of the identification of said respectively different wireless transmitter device, and wherein said computer storage stores information that associates said respectively different wireless transmitter device with said one workstation and one said different components used thereby.

10. A system according to claim 9, wherein said wireless transmitter device is operative to provide an indication of the transmission of said signal.

11. A system according to claim 9, wherein said processing subsystem is operative to process said signal as detected at a plurality of spatially separated transmission readers to locate said each wireless transmitter device.

12. A system according to claim 11, wherein said processing subsystem is operative to process signals detected at said plurality of said spatially separated transmission readers to determine which signals received by said plurality of transmission readers are first-to-arrive signals as transmitted from said each wireless transmitter device, and to conduct time-of-arrival differentiation of said first-to-arrive signals to locate said each wireless transmitter device in said manufacturing facility.

13. A system according to claim 9, wherein said each wireless transmitter device is operative to repetitively transmit said signal in response to the application of said stimulus.

14. A system according to claim 9, wherein said each wireless transmitter device is operative to randomly and repetitively transmit a signal irrespective of said stimulus that is encoded with the identification of the wireless transmitter to enable periodic and updated location of the wireless transmitter.

15. A system according to claim 9, wherein said each wireless transmitter device includes memory which stores a multibit word representative of the identification of said each wireless transmitter device, and is further operative to repetitively transmit a spread spectrum signal encoded with said information representative of the identification of said each wireless transmitter device.

16. A system according to claim 12, wherein said processing subsystem includes matched filter correlators, each having a plurality of matched filter banks containing parallel correlators which are operative to correlate a received signal with successively time offset versions of a reference pseudo random spreading code corresponding to that of spread spectrum signals transmitted by said each wireless transmitter device.

17. A system for controlling replenishment of components used by workstations of a manufacturing facility to produce an item, replenished components being retrieved from storage and delivered to said workstations, said system comprising:

at or in proximity of a workstation, a call tag containing a wireless transmitter, which is operative, in response to a stimulus applied to said call tag associated with a request for replenishment of a component used by said workstation, to controllably transmit a signal encoded with the identification of said call tag;

at least one call tag transmission reader, which is operative to detect said signal transmitted by said wireless transmitter;

a reader output processing subsystem, which is operative to process signals detected by said at least one call tag transmission reader to identify said call tag;

a relational database containing information that associates respective ones of said call tags with respective ones of said plurality of different components and workstations associated therewith, and being responsive to the identity of said call tag, to indicate what component is to be replenished at said workstation, wherein one of said workstations uses different components in production of said item, and wherein a respectively different wireless transmitter device is provided at said one workstation for each of said different components, said respectively different wireless transmitter device being operative to controllably transmit a signal encoded with information representative of the identification of said respectively different wireless transmitter device, and wherein said computer storage stores information that associates said respectively different wireless transmitter device with said one workstation and one said different components used thereby.

18. A system according to claim 17, wherein said call tag is operative to indicate transmission of said signal therefrom.

19. A system according to claim 17, wherein said wireless transmitter is operative to repetitively transmit said signal in response to application of said stimulus.

20. A system according to claim 17, wherein said wireless transmitter includes memory which stores a multibit word representative of the identification of said call tag, and is further operative to repetitively transmit a spread spectrum signal encoded with said multibit word.