Fuzzy logic control for an electric clothes dryer

• US 6,446,357 B2
• Filed: 06/21/2001
• Issued: 09/10/2002
• Est. Priority Date: 06/30/2000
• Status: Expired due to Term

• Current Assignee: Whirlpool Corporation
• Original Assignee: Whirlpool Corporation
• Inventors: Woerdehoff, Christopher J., Reck, Andrew C., Szynal, Joseph M., Maddix, Beth A., Glotzbach, Patrick J.
• Primary Examiner(s): Lazarus, Ira S.
• Assistant Examiner(s): RINEHART, KENNETH
• Application Number:
  US09/886,717
• Publication Number:
  US 20020000049A1
• Time in Patent Office: 446 Days
• Field of Search: 344/91, 344/95, 344/93, 344/96, 344/74, 344/75, 344/97, 345/57, 346/06, 345/62, 344/99
• US Class Current: 34/491
• CPC Class Codes: D06F 2101/20 Operation modes, e.g. delicate laundry washing programs, service modes or refreshment cycles
• CPC Class Codes: D06F 2103/02 Characteristics of laundry or load
• CPC Class Codes: D06F 2103/08 Humidity
• CPC Class Codes: D06F 2103/10 expressed as capacitance or resistance
• CPC Class Codes: D06F 2103/32 Temperature
• CPC Class Codes: D06F 2103/38 Time, e.g. duration
• CPC Class Codes: D06F 2105/28 Electric heating
• CPC Class Codes: D06F 58/38 of drying, e.g. to achieve the target humidity
• CPC Class Codes: D06F 58/46 Control of the operating time

Abstract

A method and apparatus for controlling the drying cycle of a dryer by utilizing fuzzy logic control. Control is accomplished by first monitoring the moisture level of a clothes load in the dryer. From the monitored moisture information, variables such as the elapsed time from the start of the drying cycle to a point when no significant moisture is detected for a specified time period and the number of times higher moisture registrations occur during another specified time period are determined. Based on the determined variables, fuzzy logic is used to determine characteristics particular to the clothes load being dried, such as size of the load. Using the determined characteristics in conjunction with user settings more accurate control of the time of drying heat application, reduced drying heat application and cool down time can be accomplished.

Claims

1. A method for controlling a dryer comprising the steps of:

selecting a first prescribed drying cycle setting prior to a start of a drying cycle;

monitoring moisture information within the dryer over a predetermined period of time; and

setting a first additional time period for the clothes load to reach a predetermined damp condition and a second additional time period for the clothes load to reach a predetermined dry condition for the drying cycle using predetermined fuzzy logic functions and rules based on the selected first prescribed drying cycle setting and at least the monitored moisture information.

2. A method for controlling a dryer comprising the steps of:

selecting a first prescribed drying cycle setting prior to a start of a drying cycle;

monitoring the moisture content of the clothes load to determine a first parameter based on the time from the start of the cycle to when moisture indications reach a predetermined level;

monitoring the moisture content of the clothes load over a predetermined period of time to determine a second parameter based on the number of determinations that moisture indications exceeded a predetermined threshold; and

setting at least a portion of a time of the drying cycle using predetermined fuzzy logic functions and rules based on the selected first prescribed drying cycle setting and the first and second monitored moisture parameters.

3. The method according to claim 2, wherein the first prescribed drying cycle is selected from the group which includes at least one of cotton/towels load cycle, jeans load cycle, normal load cycle, delicate/casual load cycle, bulky load cycle and ultra-delicate clothing load cycle.

17. The method according to claim 2, further comprising the steps of:

monitoring exhaust temperature of the dryer;

varying at least one of the drying cycle time and dryer input temperature based on the monitored exhaust temperature using the predetermined fuzzy logic.

4. A method for controlling a dryer comprising the steps of:

selecting a first prescribed drying cycle setting prior to a start of a drying cycle;

monitoring moisture information within the dryer over a predetermined period of time; and

setting at least a portion of a time of the drying cycle using predetermined fuzzy logic functions and rules based on the selected first prescribed drying cycle setting and at least the monitored moisture information, wherein the step of monitoring the moisture information further comprises the steps of;

counting a first number of moisture indications occurring in a moisture sensor within a prescribed time interval and determining whether the first number of moisture indications exceeds a predetermined threshold during the prescribed time interval; and

summing a number of determinations that the first number of moisture indications has exceeded the predetermined threshold during the predetermined period of time.

5. The method according to claim 4, wherein the prescribed time interval is 135 milliseconds.

6. The method according to claim 5, wherein the predetermined threshold is 25 moisture indications.

7. The method according to claim 4, wherein the predetermined period of time is 5 minutes.

8. The method according to claim 4, further comprising:

determining at least one characteristic of a clothes load using a fuzzy logic function based on the sum of the number of determinations that the first number of moisture indications has exceeded the predetermined threshold during the predetermined period of time; and

calculating a fuzzy logic rule using the predetermined fuzzy logic that establishes control of at least one characteristic of the drying cycle based on one or more of the determined at least one characteristic of the clothes load and the first prescribed drying cycle setting.

9. The method according to claim 8, wherein the at least one characteristic of the clothes load includes a size of the clothes load.

10. The method according to claim 8, wherein the at least one characteristic of the drying cycle includes at least one of additional drying time and additional damp time.

11. The method according to claim 4, wherein the step of monitoring the moisture information further comprises the steps of:

starting a time count from the start of the drying cycle;

determining moisture indications occurring in a moisture sensor in relation to a predetermined moisture level; and

stopping the time count when moisture indications occurring in the moisture sensor do not exceed the predetermined moisture level for a prescribed time period and storing the time count when stopped.

12. The method according to claim 11, wherein the prescribed time period is 120 seconds.

13. The method according to claim 11, wherein the predetermined moisture level threshold is 25 moisture indications occurring during a 135 millisecond time period.

14. The method according to claim 11, further comprising the steps of:

determining at least one characteristic of a clothes load using a fuzzy logic function based on the stored time; and

calculating a fuzzy logic rule using the predetermined fuzzy logic that establishes control of at least one characteristic of the drying cycle based on one or more of the determined at least one characteristic of the clothes load and the first prescribed drying cycle setting.

15. The method according to claim 14, wherein the at least one characteristic of the clothes load includes a size of the clothes load.

16. The method according to claim 14, wherein the at least one characteristic of the drying cycle includes at least one of additional drying time and additional damp time.

18. A control apparatus utilizing fuzzy logic for a controlling a dryer comprising:

a user interface for receiving a drying cycle selection from a user;

at least one moisture sensor for sensing moisture level of a clothes load in the dryer; and

a controller including a fuzzy logic portion;

said controller receiving inputs from the user interface and the at least one moisture sensor and configured to determine a first time dependent parameter based on the time from the start of the cycle to when moisture indications from the at least one moisture sensor reach a predetermined level, and a second parameter based on the number of determinations that moisture indications exceeded a predetermined threshold in a predetermined period, and to input the first and second parameters to the fuzzy logic control portion, and the fuzzy logic control portion configured to apply fuzzy logic rules that determine drying cycle modification information based on predetermined fuzzy logic functions within the fuzzy logic portion, which determines clothes load characteristics based on the first and second parameters, and to output the drying cycle modification information to controller, which modifies the drying cycle in accordance with the drying cycle modification information.

19. The apparatus according to claim 18, wherein the drying cycle selection includes drying cycles selected from the group which includes at least one of cotton/towels load cycle, jeans load cycle, normal load cycle, delicate/casual load cycle, bulky load cycle and ultra-delicate clothing load cycle.

25. The apparatus according to claim 18, wherein the at least one clothes load characteristic includes a size of the clothes load.

26. The apparatus according to claim 18, wherein the drying cycle modification information includes at least one of additional drying time and additional damp time.

27. The apparatus according to claim 18, wherein the controller is configured to start a time count from a start of the drying cycle, determine moisture indications occurring in the at least one moisture sensor in relation to a predetermined moisture level, and stop the time count when moisture indications occurring in the moisture sensor do not exceed the predetermined moisture level for a prescribed time period and storing the time count when stopped.

28. The apparatus according to claim 27, wherein the prescribed time period is 120 seconds.

29. The apparatus according to claim 27, wherein the predetermined moisture level threshold is 25 moisture indications occurring during a 135 millisecond time period.

30. The apparatus according to claim 27, wherein the fuzzy logic control portion is configured to determine at least one of the clothes load characteristics using a fuzzy logic function based on the stored time, and calculate a fuzzy logic rule using the predetermined fuzzy logic that establishes control of at least one characteristic of the drying cycle based on one or more of the determined at least one clothes load characteristic and the drying cycle selection.

31. The apparatus according to claim 30, wherein the at least one clothes load characteristic includes a size of the clothes load.

32. The apparatus according to claim 30, wherein the drying cycle modification information includes at least one of additional drying time and additional damp time.

33. The apparatus according to claim 18, further comprising:

a dryer exhaust temperature monitor inputting a signal to the controller; and

wherein the controller is configured to vary at least one of the drying cycle time and dryer input temperature based on the monitored exhaust temperature using the fuzzy logic control portion.

20. A control apparatus utilizing fuzzy logic for a controlling a dryer comprising:

a user interface for receiving a drying cycle selection from a user;

at least one moisture sensor for sensing moisture level of a clothes load in the dryer; and

a controller receiving inputs from the user interface and the at least one moisture sensor, the controller including a fuzzy logic control portion and configured to determine one or more time dependent parameters based on information input from the at least one moisture sensor and input the one or more parameters to the fuzzy logic control portion, and the fuzzy logic control portion configured to apply fuzzy logic rules that determine drying cycle modification information based on predetermined fuzzy logic functions within the fuzzy logic portion, which determines clothes load characteristics based on the one or more parameters, and to output the drying cycle modification information to controller, which modifies the drying cycle in accordance with the drying cycle modification information, wherein the controller is configured to determine at least one of the time dependent parameters by counting a first number of moisture indications occurring in a moisture sensor within a prescribed time interval and determining whether the first number of moisture indications exceeds a predetermined threshold during the prescribed time interval, and sum a number of determinations that the first number of moisture indications has exceeded the predetermined threshold during the predetermined period of time.

21. The apparatus according to claim 20, wherein the prescribed time interval is 135 milliseconds.

22. The apparatus according to claim 21, wherein the predetermined threshold is 25 moisture indications.

23. The apparatus according to claim 20, wherein the predetermined period of time is 5 minutes.

24. The apparatus according to claim 20, wherein the fuzzy logic control portion is configured to determine the at least one characteristic of the clothes load using a predetermined fuzzy logic function based on the sum of the number of determinations that the first number of moisture indications has exceeded the predetermined threshold during the predetermined period of time.

34. A method for controlling a dryer comprising the steps of:

selecting a first prescribed drying cycle setting prior to a start of a drying cycle;

monitoring the moisture content of the clothes load to determine a first parameter based on the time from the start of the cycle to when moisture indications reach a predetermined level;

monitoring the moisture content of the clothes load over a predetermined period of time to determine a second parameter based on the number of determinations that moisture indications exceeded a predetermined threshold; and

setting a first additional time period for the clothes load to reach a predetermined damp condition and a second additional time period for the clothes load to reach a predetermined dry condition for the drying cycle using predetermined fuzzy logic functions and rules based on the selected first prescribed drying cycle setting and the first and second parameters.

35. A control apparatus utilizing fuzzy logic for automatically controlling the duration of a clothes dryer cycle comprising:

a user interface for receiving a drying cycle selection from a user;

at least one moisture sensor for sensing moisture level of the clothes load in the dryer; and

a controller including a fuzzy logic control portion;

said controller receiving inputs from the user interface and the at least one moisture sensor and configured to determine one or more time dependent parameters based on information input from the at least one moisture sensor and the user interface input, and to input the one or more parameters to the fuzzy logic control portion; and

said fuzzy logic control portion configured to determine clothes load characteristics based on the user interface input and the one or more parameters and to apply fuzzy logic rules that determine a first additional drying time for the clothes load to reach a predetermined damp condition and a second additional drying time to reach a predetermined dry condition based on predetermined fuzzy logic functions within the fuzzy logic portion, and output the additional drying time information to the controller to incorporate the first and second additional drying times into the drying cycle.

36. A control apparatus utilizing fuzzy logic for a controlling a dryer comprising:

a user interface for receiving a drying cycle selection from a user;

at least one moisture sensor for sensing moisture level of a clothes load in the dryer; and

a controller including a fuzzy logic portion;

said controller receiving inputs from the user interface and the at least one moisture sensor and configured to determine a first time dependent parameter based on the time from the start of the cycle to when moisture indications from the at least one moisture sensor reach a predetermined level, and a second parameter based on the number of determinations that moisture indications exceeded a predetermined threshold in a predetermined period, and to input the user interface input and the first and second parameters to the fuzzy logic control portion; and

said fuzzy logic control portion configured to determine clothes load characteristics based on the user interface input and said first and second parameters and to apply fuzzy logic rules that determine a first additional drying time for the clothes load to reach a predetermined damp condition and a second additional drying time to reach a predetermined dry condition, and to output the additional drying time information to controller to incorporate the first and second additional drying times into the drying cycle.