Clothes fabric type blend detection method and apparatus

• US 5,897,672 A
• Filed: 12/05/1997
• Issued: 04/27/1999
• Est. Priority Date: 12/05/1997
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Bonissone, Piero Patrone, Badami, Vivek Venugopal, Dausch, Mark Edward
• Primary Examiner(s): Stinson, Frankie L.
• Application Number:
  US08/985,823
• Time in Patent Office: 508 Days
• Field of Search: 8/158, 8/159, 68/12.02, 68/12.04, 68/12.05, 68/12.21
• US Class Current: 8/159
• CPC Class Codes: D06F 2103/04 Quantity, e.g. weight or variation of weight
• CPC Class Codes: D06F 2103/06 Type or material
• CPC Class Codes: D06F 2103/18 Washing liquid level
• CPC Class Codes: D06F 34/18 Condition of the laundry, e.g. nature or weight

Abstract

A method and apparatus for detecting the relative proportion of various fabric types present in a clothes load in a clothes washer are provided, in which a set of fuzzy logic membership functions is defined at each clothes load weight across a range of expected load weights to be handled by the clothes washer, with the set of membership functions representing various fabric types that might be present in the clothes load. The membership functions are defined at least in part by a washer operating state that is to be sensed during initial washer operation, and the method includes obtaining a value for the clothes load weight, sensing a value of the washer operating state, and determining a degree of fulfillment of the sensed value in each of the membership functions defined for that given clothes load. The degree of fulfillment represents the relative proportion of the various fabric types for which membership functions are defined, and the information regarding the resultant degrees of fulfillment may be employed in controlling the operation of the washer for optimal performance. The apparatus constitutes a washer controller having a microprocessor that receives signals corresponding to the weight of the clothes load, the sensed value of the predetermined washer operating state, and has stored therein the data necessary to generate the set of membership functions for each clothes load weight.

Claims

1. A method for detecting a mix of fabric types making up a load of items disposed in a clothes washer, comprising:

obtaining a value of a dry weight of said load of items disposed in said clothes washer;

developing for said dry weight value, a set of fuzzy logic membership functions corresponding to a plurality of fabric types that may be included in said load of items, each of said membership functions being dependent upon at least one washer operating state to be sensed;

sensing a value of said at least one washer operating state; and

computing a degree of fulfillment of the sensed value of said washer operating state in each of the set of membership functions, wherein said degree of fulfillment in each of said membership function represents the relative proportion of a fabric type represented by each of said membership functions.

2. A method as recited in claim 1, further comprising the step of determining, in advance of developing said set of fuzzy logic membership functions, a maximum and a minimum possible value of said at least one washer operating state at said dry weight load value, and wherein said maximum and minimum values are employed in said developing of said set of fuzzy logic membership functions.

3. A method as recited in claim 2 further comprising determining, in advance of developing said set of fuzzy logic membership functions, a standard deviation in values of said at least one washer operating state at said dry weight load value, and wherein a predetermined fraction of said standard deviation is employed in said development of said set of fuzzy logic membership functions.

4. A method as recited in claim 3, wherein said set of fuzzy logic membership functions includes a first membership function developed to correspond to an all-cotton fabric load, a second membership function developed to correspond to an all-synthetic fabric load, and a third membership function developed to correspond to a fabric load consisting of a predetermined blend of cotton and synthetic fabrics.

5. A method as recited in claim 4, wherein said predetermined blend of cotton and synthetic fibers is a blend of fifty percent cotton fabric and fifty percent synthetic fabric.

6. A method as recited in claim 1, wherein said set of fuzzy logic membership functions includes a first membership function developed to correspond to an all-cotton fabric load, a second membership function developed to correspond to an all-synthetic fabric load, and a third membership function developed to correspond to a fabric load consisting of a predetermined blend of cotton and synthetic fabrics.

7. A method as recited in claim 6, wherein said predetermined blend of cotton and synthetic fibers is a blend of fifty percent cotton fabric and fifty percent synthetic fabric.

8. A method as recited in claim 1, wherein said step of sensing at least one operating state value includes sensing, during an initial agitation and water fill stage, a phase angle of an induction motor employed to drive a washer agitator, continuously computing an average value of a peak-to-peak variation in said motor phase angle, and storing said average peak-to-peak value in a memory of a washer controller at a predefined water level as water is added to said clothes washer.

9. A method as recited in claim 8, wherein said predefined water level is a water level at which average peak-to-peak motor phase angle values for different fabric types differ by the greatest amount for said dry weight load value, and wherein said method employs said stored average peak-to-peak motor phase angle value as said sensed washer operating state value in said step of computing said degree of fulfillment in each of said set of membership functions.

10. A method as recited in claim 1, wherein said step of sensing at least one operating state value comprises sensing a signal corresponding to a water level in said clothes washer as said washer is filled, and detecting a water level inflection point at which a change in water level is first reflected in said sensed signal, wherein a value of said water level inflection point comprises said washer operating state value used in computing said degree of fulfillment in each of said set of membership functions.

11. A method as recited in claim 1, wherein said step of sensing at least one operating state value comprises sensing an amplitude of oscillation of a water level signal from a water level sensor as said clothes washer is being filled with water and as said clothes load is agitated, averaging the sensed oscillation amplitudes, storing an average sensed oscillation value upon reaching a predetermined water level, and employing said stored value as said sensed value in determining the degree of fulfillment of said sensed value in said set of membership functions.

12. A method as recited in claim 1, further comprising:

developing a plurality of sets of fuzzy logic membership functions for a predetermined range of load weights capable of being handled by said clothes washer, wherein a set of membership functions for each load weight within said range of load weights represent different fabric types that may be present in a load of items, and wherein said membership functions are defined, using fuzzy logic, at least in part as a function of a value of said at least one washer operating state to be sensed, relative to a predetermined maximum and minimum value, at said load weight, of said at least one operating state;

storing said plurality of sets of membership functions in a memory of a clothes washer controller;

sensing, during an initial operation portion of a washing cycle, a value of said predetermined washer operating state;

computing said degree of fulfillment of said sensed value in each membership function by looking up, in said washer controller memory, the set of membership functions corresponding to said obtained value of said load weight, and by determining a membership value in each membership function defined at said load weight at said sensed value of said washer operating state.

13. A method as recited in claim 12, wherein each of said plurality of sets of fuzzy logic membership functions includes a first membership function developed to correspond to an all-cotton fabric load, a second membership function developed to correspond to an all-synthetic fabric load, and a third membership function developed to correspond to a fabric load consisting of a predetermined blend of cotton and synthetic fabrics.

14. A method as recited in claim 12, wherein said step of sensing at least one operating state value includes sensing, during an initial agitation and water fill stage, a phase angle of an induction motor employed to drive a washer agitator, continuously computing an average value of a peak-to-peak variation in said motor phase angle, and storing said average peak-to-peak value in a memory of a washer controller at a predefined water level as water is added to said clothes washer, wherein said predefined water level is a water level at which average peak-to-peak motor phase angle values for different fabric types differ by the greatest amount for said dry weight lead value, and wherein said method employs said stored average peak-to-peak motor phase angle value as said sensed washer operating state value in said step of computing said degree of fulfillment in each of said set of membership functions.

15. A method as recited in claim 12, wherein said step of sensing at least one operating state value comprises sensing a signal corresponding to a water level in said clothes washer as said washer is filled, and detecting a water level inflection point at which a change in water level is first reflected in said sensed signal, wherein a value of said water level inflection point comprises said washer operating state value used in computing said degree of fulfillment in each of said set of membership functions.

16. A method as recited in claim 12, wherein said step of sensing at least one operating state value comprises sensing an amplitude of oscillation of a water level signal from a water level sensor as said clothes washer is being filled with water and as said clothes load is agitated, averaging the sensed oscillation amplitudes, storing an average sensed oscillation value upon reaching a predetermined water level, and employing said stored value as said sensed value in determining the degree of fulfillment of said sensed value in said set of membership functions.

17. A method for detecting a mix of fabric types making up a load of items disposed in a clothes washer comprising:

in a calibration portion,

establishing a range of possible values of a predetermined washer operating parameter as a function of a range of fabric types, for a range of load weights capable of being processed by said clothes washer;

defining, using fuzzy logic, a plurality of sets of membership functions for said range of load weights, each membership function at each load weight corresponding to a predetermined fabric type and further being defined at least in part as a function of said predetermined washer operating parameter to be sensed; and

in a run-time portion,

obtaining a value of the load weight for the items loaded in said clothes washer;

sensing a value of said predetermined washer operating parameter;

retrieving data corresponding to said set of membership functions defined at said load weight; and

computing a degree of fulfillment of the sensed washer operating parameter in each of said membership functions corresponding to said predetermined fabric type, said degree of fulfillment in each of said membership functions indicating a relative proportion of the fabric type represented by said membership function.

18. A method as recited in claim 17, wherein each of said plurality of sets of membership functions includes a first membership function developed to correspond to an all-cotton fabric load, a second membership function developed to correspond to an all-synthetic fabric load, and a third membership function developed to correspond to a fabric load consisting of a predetermined blend of cotton and synthetic fabrics.

19. A method as recited in claim 18, wherein said predetermined blend of cotton and synthetic fibers is a blend of fifty percent cotton fabric and fifty percent synthetic fabric.

20. A washer controller comprising a microprocessor having a set of data stored therein necessary to define a set of fuzzy logic membership functions, for a given fabric load, representative of a plurality of fabric types that may be introduced into a washer,

said controller further including means for receiving an input signal generated by a washer operating state sensor and for receiving an input signal corresponding to a weight of a fabric load present in a washer;

said controller further having means for detecting a relative proportion of various predetermined fabric types in a fabric load present in a washer, by processing said operating state input signal, said fabric load weight signal and said data defining said set of fuzzy logic membership functions to determine a level of fulfillment in each membership function, at said fabric load weight, of said sensed washer operating state; and

said controller further having means for sending a control signal based upon a detected blend of fabric types to at least one washer component to control at least one washer operating parameter.