Detecting interactions with storage units based on RFID signals and auxiliary signals

Patent metadata

Field	Value
Publication number	US-11514766-B1
Application number	US-202017118417-A
Country	US
Kind code	B1
Filing date	Dec 10, 2020
Priority date	Dec 10, 2020
Publication date	Nov 29, 2022
Grant date	Nov 29, 2022

Abstract

Storage units including platforms that are outfitted with RFID antennas and auxiliary sensors detect changes in loading on the platforms based on changes in loading determined by the auxiliary sensors or changes in signals received by the RFID antennas. The platforms include surfaces for receiving items tagged with RFID transmitters thereon, such as items of common types and variable weights. An interaction involving the placement of an item on the platform, or the removal of the item from the platform, is detected by the auxiliary sensors. The energization of an RFID field is triggered in response to the detected interaction, and an item is identified where an RFID signal transmitted by the item is present at one time and absent at another time.

First claim

What is claimed is:

1. A materials handling facility comprising:
a computer system; and
a storage system comprising:
a shelf having an upper surface;
a plurality of load sensors, wherein each of the load sensors is provided on the upper surface of the shelf, and wherein each of the load sensors is configured to generate a load signal indicative of a force applied to one of the load sensors; and
a platform having an upper surface for accommodating items thereon and a lower surface resting on each of the plurality of load sensors, wherein the platform further comprises:
a plurality of RFID antennas provided in association with the upper surface of the platform, wherein each of the plurality of RFID antennas is configured to emit an RF field and to receive RFID signals;
an RFID reader;
at least one computer processor; and
a transceiver in communication with the RFID reader and the computer system,

wherein the computer system is programmed with one or more sets of instructions that, when executed, cause the computer system to at least:
receive, from the platform by way of the transceiver, a first set of data determined from a first set of RFID signals transmitted by a first set of RFID transmitters at a first time;
receive, from the load sensors, a first set of load signals generated in response to loads supplied to the plurality of load sensors at the first time;
determine a first weight on the platform at the first time based at least in part on the first set of load signals;
identify a first set of items based at least in part on the first set of data and the first weight;
in response to identifying the first set of items,
store at least one indication that the first set of items is on the first platform at the first time;

receive, from the platform by way of the transceiver, a second set of data determined from a second set of RFID signals transmitted by a second set of RFID transmitters at a second time;
receive, from the load sensors, a second set of load signals generated in response to loads supplied to the plurality of load sensors at the second time;
determine a second weight on the platform at the second time based at least in part on the second set of load signals;
identify a second set of items based at least in part on the second set of data and the second weight; and
in response to identifying the second set of items,
determine that an interaction involving an item occurred not later than the second time, wherein the item is one of:
included in the first set of items and not included in the second set of items; or
included in the second set of items and not included in the first set of items.

2. The materials handling facility of claim 1 , wherein the one or more sets of instructions, when executed, further cause the computer system to at least:
determine that one of the first set of RFID signals is not included in the second set of RFID signals;
determine a difference between the first weight and the second weight;
determine that one of the first set of RFID transmitters transmitted the one of the first set of RFID signals; and
determine that the item is associated with the one of the first set of RFID transmitters and has a weight approximately equal to the difference between the first weight and the second weight.

3. The materials handling facility of claim 1 , wherein the one or more sets of instructions, when executed, further cause the computer system to at least:
determine, based at least in part on the first set of load signals, a force applied to each of the plurality of load sensors at the first time;
determine, based at least in part on the second set of load signals, a force applied to each of the plurality of load sensors at the second time;
calculate, for each of the plurality of load sensors, a difference between the force applied to the load sensor at the first time and the force applied to the load sensor at the second time;
identify one of the plurality of load sensors having a greatest difference between the force applied to the load sensor at the first time and the force applied to the load sensor at the second time;
select one of the plurality of RFID antennas within a vicinity of the one of the plurality of load sensors having the greatest difference; and
cause the selected one of the plurality of RFID antennas to emit an RF field at the second time.

4. A method comprising:
receiving, by at least one RFID antenna associated with a first storage unit, a first set of RFID signals, wherein each of the first set of RFID signals is transmitted by one of a first set of RFID transmitters, and wherein each of the first set of RFID transmitters is associated with one of a first set of items provided on a first platform of the first storage unit at a first time;
determining that the first set of items is provided on the first platform at the first time based at least in part on the first set of RFID signals;
receiving at least a first auxiliary signal from at least a first auxiliary sensor at a second time;
determining that an interaction with the first storage unit occurred at approximately the second time based at least in part on the first auxiliary signal;
receiving, by the at least one RFID antenna associated with the first storage unit, a second set of RFID signals, wherein each of the second set of RFID signals is transmitted by one of a second set of RFID transmitters, and wherein each of the second set of RFID transmitters is associated with one of a second set of items provided on the first platform at approximately the second time;
determining that the second set of items is provided on the first platform at approximately the second time based at least in part on the second set of RFID signals; and
identifying an item associated with the interaction based at least in part on a difference between the first set of items and the second set of items,
wherein the item is in one of the first set of items or the second set of items.

5. The method of claim 4 , further comprising:
transmitting, by at least one transceiver associated with the first storage unit, a record of the interaction with the first storage unit at the second time to at least one computer system, wherein the record of the interaction comprises:
an identifier of the item;
the second time; and
a location of the first storage unit.

6. The method of claim 5 , wherein the at least one RFID antenna is in communication with an RFID reader, and
wherein each of the at least one RFID antenna, the RFID reader and the at least one transceiver is provided within the first platform.

7. The method of claim 4 , further comprising:
emitting, by the at least one RFID antenna associated with the first storage unit, at least one RF field, wherein each of the first set of RFID signals is transmitted by one of the first set of RFID transmitters within the at least one RF field; and
in response to determining that the interaction with the first storage unit occurred at approximately the second time,
emitting, by at least one RFID antenna associated with the first platform, at least one RF field, wherein each of the second set of RFID signals is transmitted by one of the second set of RFID transmitters within the at least one RF field.

8. The method of claim 4 , wherein the first storage unit is one of a plurality of storage units provided in a common structure, and
wherein each of the plurality of storage units comprises:
a platform;
at least one auxiliary sensor provided in association with the platform;
at least one RFID antenna provided in association with the platform; and
an RFID reader in communication with the at least one RFID antenna.

9. The method of claim 4 , whe

Assignees

• Amazon Tech Inc

Inventors

• Mcdaniel Aaron M
• O'Neill Nathan P
• Doshi Nirmal
• Tang Yuxing
• Colwill Robert Jerome

Classifications

• G08B13/1472 Primary

  with force or weight detection · CPC title

• G08B13/2417

  having a radio frequency identification chip · CPC title

• G08B13/246

  Check out systems combined with EAS, e.g. price information stored on EAS tag (anti-theft systems in point of sale systems G07G3/003) · CPC title

• G08B13/2485

  Simultaneous detection of multiple EAS tags · CPC title

• G08B13/248

  EAS system combined with another detection technology, e.g. dual EAS and video or other presence detection system · CPC title