Management of inventory items

• US 9,378,484 B1
• Filed: 12/02/2014
• Issued: 06/28/2016
• Est. Priority Date: 12/02/2014
• Status: Active Grant

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Inventors: Ryle, Thomas Matthew, Wood, James Hollis, Russell, Ryan Scott, Lauka, Wesley Scott, Phillips, Jonathan David
• Primary Examiner(s): Vo, Tuyen K
• Application Number:
  US14/558,568
• Time in Patent Office: 574 Days
• Field of Search: 235/385, 235/383
• US Class Current: 1/1
• CPC Class Codes: G06K 19/07758 arrangements for adhering the record carrier to further objects or living beings, functioning as an identification tag
• CPC Class Codes: G06K 7/10099 the directional field being used for pinpointing the location of the record carrier, e.g. for finding or locating an RFID tag amongst a plurality of RFID tags, each RFID tag being associated with an object, e.g. for physically locating the RFID tagged object in a warehouse
• 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: G06Q 10/087 Inventory or stock management, e.g. order filling, procurement or balancing against orders
• CPC Class Codes: G06Q 10/0875 Itemisation or classification of parts, supplies or services, e.g. bill of materials

Abstract

In some examples, a reader system is provided for managing inventory items in an inventory system. The reader system may be configured to read tags associated with items stowed in an inventory holder. The inventory holder may be detachably coupled to a mobile drive unit. The mobile drive unit may move the inventory holder to a first position near an antenna of the reader system and the tags may begin to be read. While reading or at other times in the reading process, the mobile drive unit may move the inventory holder relative to the antenna. The identified tags may be compared to a manifest list of items expected to be stowed in the inventory holder.

Claims

1. A computer-implemented method, comprising:

(a) identifying an inventory holder by reading a first radio-frequency identification (RFID) tag associated with the inventory holder, the inventory holder coupled to an autonomous mobile drive unit and comprising one or more compartments configured to receive items, the autonomous mobile drive unit configured to lift the inventory holder and to transport the inventory holder from a first position to a second position;

(b) transmitting a radio frequency transmission via one or more antennas in a direction of the inventory holder;

(c) receiving, by at least one reader, radio frequency responses via the one or more antennas, the radio frequency responses provided by one or more RFID tags in response to the radio frequency transmission, each RFID tag associated with an item stowed in the inventory holder;

(d) identifying, based at least in part on the radio frequency responses, items stowed in the inventory holder;

(e) instructing rotation of the inventory holder relative to the one or more antennas by the autonomous mobile drive unit, wherein the receiving of the radio frequency responses and the identifying of the items stowed occur at least partly during the rotation of the inventory holder by the autonomous mobile drive unit;

(f) receiving a manifest comprising a list of manifest items expected to be stowed in the inventory holder; and

(g) comparing the list of manifest items with the identified items stowed in the inventory holder in accordance with a confidence threshold.

2. The computer-implemented method of claim 1, wherein the receiving of the radio frequency responses and the identifying of the items stowed occur until the confidence threshold is met, the confidence threshold indicating that a predetermined percentage of items from the list of manifest items have been identified as the items stowed in the inventory holder.

3. The computer-implemented method of claim 1, further comprising providing a notification when the confidence threshold is not met after a predetermined time.

4. The computer-implemented method of claim 1, wherein comparing the list of manifest items with the identified items stowed in the inventor holder in accordance with the confidence threshold comprises comparing the list of manifest items with the identified items stowed in the inventory holder at least until the confidence threshold has been fulfilled, and wherein the method further comprises instructing cessation of the rotation of the inventory holder relative to the one or more antennas by the autonomous mobile drive unit after the confidence threshold has been fulfilled.

5. A computer-implemented method, comprising:

reading a first radio-frequency identification (RFID) tag associated with an inventory holder to identify the inventory holder, the inventory holder detachably coupled to an autonomous mobile drive unit and comprising a plurality of items stowed in one or more compartments of the inventory holder, the autonomous mobile drive unit configured to lift the inventory holder and to transport the inventory holder;

reading, via an antenna, a first portion of a plurality of RFID tags associated with the plurality of items to identify a first portion of the plurality of items when the inventory holder is located at a first position relative to the antenna;

reading, via the antenna, a second portion of the plurality of RFID tags associated with the plurality of items to identify a second portion of the plurality of items after the autonomous mobile drive unit has moved the inventory holder to a second position relative to the antenna;

determining a completion of the reading of the plurality of RFID tags in accordance with a threshold; and

providing at least a portion of inventory information to an inventory management system, the portion of the inventory information at least including the identified portions of the plurality of items.

6. The computer-implemented method of claim 5, further comprising:

instructing the autonomous mobile drive unit to move the inventory holder to the first position prior to reading the first portion of the plurality of RFID tags;

instructing the autonomous mobile drive unit to move the inventory holder from the first position to the second position at least by rotating the inventory holder; and

reading a third portion of the plurality of RFID tags associated with the plurality of items to identify a third portion of the plurality of items while the autonomous mobile drive unit rotates the inventory holder.

7. The computer-implemented method of claim 5, wherein the reading at the first position and the reading at the second position are performed when the inventory holder is coupled to the autonomous mobile drive unit.

8. The computer-implemented method of claim 5, further comprising:

determining, based at least in part on the reading of the portions of the plurality of RFID tags, an identified list of items, the identified list of items including items whose associated RFID tags have been identified;

receiving a manifest list of items from the inventory management system, the manifest list of items including items expected to be stowed in the inventory holder; and

comparing the manifest list of items with the identified list of items to determine a list of missing items.

9. The computer-implemented method of claim 8, wherein determining the completion of the reading of the plurality of RFID tags in accordance with the threshold includes determining the completion of the reading when the list of missing items includes a quantity of items below the threshold.

10. The computer-implemented method of claim 5, wherein the threshold comprises a confidence threshold indicating a confidence level that all RFID tags in the inventory holder have been read.

11. The computer-implemented method of claim 5, wherein the threshold comprises a time threshold indicating a period of time during which the reading of the plurality of RFID tags will be performed.

12. The computer-implemented method of claim 5, wherein the plurality of RFID tags comprise unique RFID tags and each unique RFID tag is attached to and uniquely identifies an item of the plurality items.

13. The computer-implemented method of claim 5, wherein the portion of the inventory information includes a first portion and a second portion, the first portion of inventory information including a first list of items corresponding to the first portion of the plurality of RFID tags and the second portion including a second list of items corresponding to the second portion of the plurality of RFID tags, at least part of the first portion of inventory information provided to the inventory management system before the autonomous mobile drive unit moves the inventory holder to the second position.

14. The computer-implemented method of claim 5, wherein the reading of the plurality of RFID tags includes:

transmitting a radio frequency transmission via the antenna in a direction of the inventory holder;

receiving, by at least one reader, radio frequency responses via the antenna, the radio frequency responses provided by the plurality of RFID tags in response to the radio frequency transmission; and

identifying, based at least in part on the radio frequency responses, the plurality of items stowed in the one or more compartments of the inventory holder.

15. The computer-implemented method of claim 5, further comprising, after the completion of the reading, generating a report indicating one or more items expected to be stowed in the inventory holder that were not identified by the reading of the plurality of RFID tags.

16. A system, comprising:

an antenna;

an inventory management system configured to store an inventory manifest; and

a reader in communication with the inventory management system and the antenna, the reader comprising;

memory that stores computer-executable instructions; and

at least one processor configured to access the memory and execute the computer-executable instructions to at least;

read a first radio-frequency identification (RFID) tag associated with an inventory holder, the inventory holder comprising one or more compartments and detachably coupled to an autonomous mobile drive unit, the autonomous mobile drive unit configured to lift the inventory holder and to transport the inventory holder;

read, via the antenna, a second RFID tag identifying a first item, the first item associated with the second RFID tag and stowed in the inventory holder;

read, via the antenna, a third RFID tag identifying a second item in response to the autonomous mobile drive unit adjusting an orientation of the inventory holder relative to the antenna, the second item associated with the third tag and stowed in the inventory holder; and

provide tag information to the inventory management system, the tag information including identifiers associated with at least the first, second and third RFID tags.

17. The system of claim 16, wherein the at least one processor is further configured to access the memory and execute the computer-executable instructions to at least:

cease reading, via the antenna, in accordance with a threshold.

18. The system of claim 17, wherein ceasing reading in accordance with the threshold includes ceasing reading after lapse of a period of time corresponding to the threshold.

19. The system of claim 17, wherein ceasing reading in accordance with the threshold includes ceasing reading after receiving an instruction from the inventory management system to stop reading, the inventory management system determining the instruction based at least in part on a comparison of the tag information with the inventory manifest associated with the inventory holder.

20. The system of claim 16, wherein the autonomous mobile drive unit adjusting the orientation of the inventory holder relative to the antenna comprises the autonomous mobile drive unit rotating the inventory holder about a rotation axis substantially parallel to a vertical dimension of the inventory holder.