System to mitigate effects of vibration on load cell

• US 10,612,964 B1
• Filed: 12/21/2016
• Issued: 04/07/2020
• Est. Priority Date: 12/21/2016
• Status: Active Grant

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Inventors: Shi, Qicai, O'Neill, Nathan Pius
• Primary Examiner(s): Barbee, Manuel L
• Assistant Examiner(s): Nimox, Raymond L
• Application Number:
  US15/387,469
• Time in Patent Office: 1,203 Days
• CPC Class Codes: G01G 19/414 using electronic computing means only
• CPC Class Codes: G01G 19/42 for counting by weighing G01G19/387 takes precedence
• CPC Class Codes: G01G 23/00 Auxiliary devices for weighing apparatus
• CPC Class Codes: G01G 23/10 by electric or magnetic means
• CPC Class Codes: G06Q 10/087 Inventory or stock management, e.g. order filling, procurement or balancing against orders

Abstract

Shelves or other fixtures may be used to support items at a facility. Load cells at the fixtures may be used to acquire weight data indicative of changes to the fixture as items are added or removed from the fixture. Vibration of the fixtures may introduce noise into the weight data, resulting in inaccurate weight data. Described are techniques for utilizing a vibration sensor on the fixture to determine the presence of vibration. In one implementation, weight data obtained during vibration may be disregarded. In another implementation, data from the vibration sensor may be used to adaptively adjust values of the weight data. By utilizing the information from the vibration sensor, more accurate weight data is obtained. The weight data may then be used to determine a count of items at the fixture, determine a quantity of items picked or placed, and so forth.

Claims

1. A system comprising:

a shelf;

a load cell configured to measure weight of at least a portion of a load on the shelf;

a vibration sensor comprising a gyroscope mounted to the shelf;

a communication interface; and

a computing device comprising;

a first memory storing first computer-executable instructions; and

a first hardware processor to execute the first computer-executable instructions to;

acquire first weight data from the load cell during a first interval;

acquire second weight data from the load cell during a second interval;

acquire first vibration data from the vibration sensor during the first interval;

acquire second vibration data from the vibration sensor during the second interval;

determine a first vibration value using the first vibration data;

determine the first vibration value exceeds a threshold value;

designate the first weight data occurring at the first interval and for a duration of time thereafter as invalid weight data;

determine a second vibration value using the second vibration data;

determine the second vibration value is less than or equal to the threshold value; and

send the second weight data to a server using the communication interface.

2. The system of claim 1, further comprising:

a support structure; and

wherein a back of the shelf is attached to the support structure, a front of the shelf is distal to the support structure, and the vibration sensor is mounted proximate to the front of the shelf.

3. A system comprising:

a fixture comprising a shelf;

one or more load cells configured to measure weight of at least a portion of the fixture;

a first vibration sensor mounted proximate to a front of the shelf;

a communication interface; and

a computing device comprising;

a first memory storing first computer-executable instructions; and

a first hardware processor to execute the first computer-executable instructions to;

access weight data from the one or more load cells;

access vibration data from the first vibration sensor;

determine a vibration threshold value; and

determine validity data indicative of validity of at least a portion of the weight data based on a comparison of the vibration data and the vibration threshold value.

4. The system of claim 3, wherein the first vibration sensor comprises one or more of a piezoelectric element, a gyroscope, an accelerometer, an optical vibrometer, or a mechanical vibrometer.

5. The system of claim 3, further comprising a second vibration sensor that is one or more of affixed to or at least partially within a floor.

6. The system of claim 3, wherein the fixture further comprises a second shelf and a second vibration sensor, and further wherein the second vibration sensor is mounted proximate to a front of the second shelf.

7. The system of claim 3, wherein the fixture comprises:

a support structure;

the shelf supported by the one or more load cells is attached to the support structure; and

wherein a second vibration sensor is mounted on the support structure.

8. The system of claim 3, further comprising a server, the server comprising:

a second memory storing second computer-executable instructions; and

a second hardware processor to execute the second computer-executable instructions to;

receive the weight data;

receive the vibration data;

determine a vibration value using at least a portion of the vibration data; and

based on the vibration value, determine validity of the at least a portion of the weight data.

9. The system of claim 8, the second computer-executable instructions to determine the vibration value further comprising instructions to:

determine the at least a portion of the weight data was obtained contemporaneously with the at least a portion of the vibration data.

10. The system of claim 8, wherein the vibration data comprises a plurality of values that are indicative of one or more of rotation, velocity, acceleration, or displacement;

and the second computer-executable instructions to determine the vibration value further comprising instructions to;

calculate a root mean square of the plurality of values.

11. The system of claim 3, further comprising a server, the server comprising:

a second memory storing second computer-executable instructions; and

a second hardware processor to execute the second computer-executable instructions to;

receive the weight data;

receive the vibration data;

determine a vibration value using at least a portion of the vibration data;

determine a time interval associated with the at least a portion of the vibration data; and

apply a filter to the weight data that corresponds to the time interval to generate filtered weight data.

12. The system of claim 11, the filter further comprising a notch filter that attenuates values of a portion of the weight data that exhibits values representative of vibration within a particular frequency range;

and

wherein the filtered weight data comprises weight data in which the values representative of the vibration within the particular frequency range have a lower amplitude than in the weight data.

13. The system of claim 12, the server further comprising:

the second memory storing third computer-executable instructions; and

the second hardware processor to execute the third computer-executable instructions to;

generate interaction data at least in part using the filtered weight data.

14. The system of claim 3, further comprising a server, the server comprising:

a second memory storing second computer-executable instructions; and

a second hardware processor to execute the second computer-executable instructions to;

determine a location of the first vibration sensor as mounted proximate to the front of the shelf;

receive the weight data;

receive the vibration data;

determine a vibration value using at least a portion of the vibration data;

determine the vibration threshold value based on the location; and

compare the vibration value to the vibration threshold value.

15. A method comprising:

accessing weight data indicative of a weight on at least a portion of a fixture, wherein the fixture comprises a shelf and a support structure, and wherein the weight data is obtained from a load cell;

accessing vibration data indicative of vibration of the at least a portion of the fixture, wherein the vibration data is obtained from a sensor mounted to a front edge of the shelf of the fixture or mounted to the support structure of the fixture;

determining a vibration value using the vibration data; and

determining validity of the weight data based on the vibration value.

16. The method of claim 15, the determining the vibration value comprising calculating a root mean square of a plurality of one or more values indicative of one or more of rotation, velocity, acceleration, or displacement.

17. The method of claim 15, further comprising:

determining a total weight measured by the load cell;

determining a threshold value based on the total weight; and

wherein the determining the validity of the weight data comprises comparing the vibration value to the threshold value.

18. The method of claim 15, further comprising:

determining a type of the fixture, wherein the type is indicative of construction of the fixture;

determining a threshold value based on the type of the fixture; and

wherein the determining the validity of the weight data comprises comparing the vibration value to the threshold value.

19. The method of claim 15, wherein at least a portion of the vibration data is obtained at least in part contemporaneously with at least a portion of the weight data.

20. The method of claim 15, further comprising:

determining the vibration value exceeds a threshold value;

determining a duration of time; and

designating the weight data occurring at a first time and for the duration of time thereafter as invalid weight data.

21. The method of claim 20, wherein the determining the duration of time is based on one or more of:

construction of the fixture,

previously determined total weight on the fixture, or

placement of the sensor with respect to the fixture.