DETECTION OF CONTAMINATION STATUS FOR REFRIGERATOR ULTRASONIC SENSOR ASSEMBLY

• US 20150033822A1
• Filed: 08/01/2013
• Published: 02/05/2015
• Est. Priority Date: 08/01/2013
• Status: Active Grant

• Current Assignee: Haier US Appliance Solutions, Inc. DBA GE Appliances (Haier Group Company)
• Original Assignee: General Electric Company
• Inventors: Crosby, Jonathan Charles, Doering, Tyler James, Waugh, Joseph Thomas
• Granted Patent: US 9,395,232 B2
• Time in Patent Office: Days
• US Class Current: 73/1.82
• CPC Class Codes: G01F 23/2962 Measuring transit time of reflected waves
• CPC Class Codes: G01F 25/20 of apparatus for measuring liquid level

Abstract

Systems and methods for detecting a contamination status of an ultrasonic sensor assembly included in a refrigeration appliance are provided. An exemplary refrigerator includes a sensor assembly. The sensor assembly includes a first ultrasonic sensor configured to transmit an ultrasonic signal and a second ultrasonic sensor configured to receive the ultrasonic signal. The refrigerator is configured to perform operations comprising detecting whether the sensor assembly is contaminated based on one or more characteristics of the received ultrasonic signal. An exemplary method includes monitoring a change in a characteristic of a plurality of crosstalk components of a plurality of ultrasonic signals of over a period of time to detect a contaminated state of an ultrasonic sensor.

Claims

1. A refrigerator, comprising:

a sensor assembly comprising;

a first ultrasonic sensor configured to transmit an ultrasonic signal; and

a second ultrasonic sensor configured to receive the ultrasonic signal;

wherein the refrigerator is configured to perform operations comprising detecting whether the sensor assembly is contaminated based on one or more characteristics of the received ultrasonic signal.

2. The refrigerator of claim 1, wherein the one or more characteristics of the received ultrasonic signal comprises an amplitude of crosstalk received at the second ultrasonic sensor.

3. The refrigerator of claim 2, wherein detecting whether the sensor assembly is contaminated based on one or more characteristics of the received ultrasonic signal comprises comparing the amplitude of crosstalk to a threshold value.

4. The refrigerator of claim 3, wherein the refrigerator detects that the sensor assembly is contaminated when the amplitude of crosstalk is greater than the threshold value.

5. The refrigerator of claim 3, wherein the refrigerator is configured to perform further operations comprising performing a calibration routine upon a system initialization to obtain the threshold value.

6. The refrigerator of claim 1, wherein detecting whether the sensor assembly is contaminated based on one or more characteristics of the received ultrasonic signal comprises:

determining a first amplitude of the received ultrasonic signal at a first time, the first time being after a predetermined amount has elapsed since a time of transmission of the ultrasonic signal from the first ultrasonic sensor; and

detecting that the sensor assembly is contaminated when the first amplitude is greater than a threshold value.

7. The refrigerator of claim 6, wherein the refrigerator is configured to perform further operations comprising determining the threshold value by performing a calibration routine upon a system initialization.

8. The refrigerator of claim 1, wherein the refrigerator is configured to perform further operations comprising providing a user alert when it is detected that the sensor assembly is contaminated.

9. The refrigerator of claim 1, wherein the refrigerator is configured to perform further operations comprising:

analyzing the portion of the ultrasonic signal received after a deadband delay to detect the presence of an object within a proximity of the sensor assembly, the deadband delay comprising an amount of time after a time of transmission of the ultrasonic signal from the first ultrasonic sensor; and

increasing the deadband delay when it is detected that the sensor assembly is contaminated.

10. The refrigerator of claim 1, wherein the first ultrasonic sensor comprises an ultrasonic transducer and the second ultrasonic sensor comprises an ultrasonic detector.

11. A method for determining a contamination status of an ultrasonic sensor assembly included in a refrigerator appliance, the method comprising:

operating the ultrasonic sensor assembly to send and receive one or more ultrasonic signals;

comparing an amount of received crosstalk to a threshold value; and

determining the contamination status of the ultrasonic sensor assembly based on the comparison of the amount of received crosstalk to the threshold value.

12. The method of claim 11, wherein:

the ultrasonic sensor assembly comprises;

a chassis;

an ultrasonic transducer; and

an ultrasonic detector; and

the received crosstalk comprises vibrations transmitted from the ultrasonic transducer to the ultrasonic detector via the chassis.

13. The method of claim 11, wherein determining the contamination status of the ultrasonic sensor assembly based on the comparison comprises detecting that the ultrasonic sensor assembly is contaminated when the amount of received crosstalk is greater than the threshold value.

14. The method of claim 11, wherein:

the ultrasonic sensor assembly comprises;

an ultrasonic transducer; and

an ultrasonic detector; and

the amount of received crosstalk comprises a first voltage generated by the ultrasonic detector at a first time following transmission of the one or more ultrasonic signals by the ultrasonic transducer.

15. The method of claim 11, wherein:

operating the ultrasonic sensor assembly to send and receive the one or more ultrasonic signals comprises;

respectively transmitting a plurality of ultrasonic signals, each ultrasonic signal having a pulse amplitude; and

respectively receiving the plurality of ultrasonic signals, the plurality of received ultrasonic signals respectively exhibiting a plurality of received crosstalk amplitudes; and

comparing the amount of received crosstalk to the threshold value comprises respectively comparing the plurality of received crosstalk amplitudes to a plurality of threshold values.

16. The method of claim 15, wherein determining the contamination status of the ultrasonic sensor assembly based on the comparison comprises detecting that the ultrasonic sensor assembly is contaminated when a majority of the plurality of received crosstalk amplitudes are greater than their respective threshold values.

17. The method of claim 15, wherein:

respectively comparing the plurality of received crosstalk amplitudes to a plurality of threshold values comprises respectively determining a plurality of variances for the plurality of received crosstalk amplitudes, each variance for each received crosstalk amplitude describing a difference between such received crosstalk amplitude and the respective threshold value to which it was compared; and

determining the contamination status of the ultrasonic sensor assembly based on the comparison comprises;

summing the plurality of variances to obtain a global variance; and

detecting that the ultrasonic sensor assembly is contaminated when the global variance is greater than zero.

18. The method of claim 11, further comprising increasing a deadband delay value when the ultrasonic sensor assembly is determined to be contaminated, the deadband delay value describing an interval of time after transmission of each of the one or more ultrasonic signals in which the corresponding received ultrasonic signal is not analyzed for object detection.

19. A method for operating an appliance, the method comprising:

transmitting, over a period of time, a plurality of ultrasonic signals from an ultrasonic transducer included in the appliance, each of the plurality of ultrasonic signals being transmitted at the same strength;

respectively receiving the plurality of ultrasonic signals at an ultrasonic detector included in the appliance;

determining, for each of the plurality of ultrasonic signals, a characteristic of a crosstalk component in each received ultrasonic signal;

monitoring a change in the characteristic of the crosstalk components over the period of time to detect a contaminated state of at least one of the ultrasonic transducer or the ultrasonic detector.

20. The method of claim 19, wherein:

monitoring the change in the characteristic of the crosstalk components comprises detecting when an amplitude of one of the crosstalk components exceeds a baseline value; and

the method further comprises increasing a latency period when the contaminated state is detected, the latency period occurring after each respective transmission of one of the plurality of ultrasonic signals.