Appliance electronic control system with programmable and reconfigurable fuzzy logic controller

• US 5,619,614 A
• Filed: 04/12/1995
• Issued: 04/08/1997
• Est. Priority Date: 10/30/1992
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Rice, Steven A., Wead, William W., Payne, Thomas R.
• Primary Examiner(s): Downs, Robert W.
• Application Number:
  US08/421,037
• Time in Patent Office: 727 Days
• Field of Search: 395/3, 395/900, 395/51, 395/61, 34/495, 34/553, 34/562, 68/12.05, 68/12.21
• US Class Current: 706/1
• CPC Class Codes: D06F 2101/10 Spin speed
• CPC Class Codes: D06F 2101/12 Washing temperature
• CPC Class Codes: D06F 2101/14 Time settings
• CPC Class Codes: D06F 2103/18 Washing liquid level
• CPC Class Codes: D06F 2103/32 Temperature
• CPC Class Codes: D06F 2105/28 Electric heating
• CPC Class Codes: D06F 34/08 Control circuits or arrangements thereof
• CPC Class Codes: G05B 19/042 using digital processors G05B19/05 takes precedence
• CPC Class Codes: G06N 7/04 Physical realisation
• CPC Class Codes: Y10S 706/90 Fuzzy logic

Abstract

An electronic control system, particularly adaptable to coin-operated laundry appliances, which enables owners of such machines to customize machine operation. Laundry parameters are stored in random access memory, and timing functions are performed in control logic. Thus, the owner may simply update the information on a computer and download the parameters to individual laundry machines. A portable receiver/transmitter may be utilized to transfer information to the laundry machine controller by way of an infrared communications link. Also disclosed is a reconfigurable fuzzy logic control which is general purpose, having a functionality that may be easily altered in accordance with the type of machine. The structure of the fuzzy logic controller is identical for all applications. Definitions of both fuzzy logic membership functions and fuzzy logic rules are input to the controller as a set of parameters, such that the fuzzy logic controller is programmably reconfigurable without any change in the actual fuzzy logic. In the disclosed embodiment, the reconfigurable and reprogrammable fuzzy logic controller is used for two different purposes, one relating to the control of a washing machine and the other to control of a clothes dryer.

Claims

1. A fuzzy logic controller comprising:

at least one input for receiving an input value;

an output;

a configuration input for receiving definitions of at least one set of input membership functions corresponding to said at least one input, definitions of a set of output membership functions, and a set of inferencing rules each defined as a plurality of control bits;

memory elements for storing input membership function definitions, output membership function definitions and inferencing rules;

updating elements connected to said configuration input and to said memory elements for updating membership functions and inferencing rules in said memory elements while inferencing rules are being processed during operation of the fuzzy logic controller;

elements for calculating a degree of belief for each of the stored input membership functions based on the input value;

an inference engine operable, for each of the stored set of inferencing rules, to calculate a scaled value for a particular output membership function based on at least one input membership function degree of belief in accordance with control bits of the inferencing rule; and

elements for calculating a crisp value based on the calculated scaled values and for outputting the crisp value to said output.

2. A fuzzy logic controller in accordance with claim 1, which further comprises a communication link connected to said fuzzy logic controller for inputting membership function definitions and inferencing rules to be stored in said memory elements, the input membership functions and output membership functions being structured for direct entry.

3. A fuzzy logic controller in accordance with claim 1, which comprises a pair of inputs for receiving a corresponding pair of input values.

4. A fuzzy logic controller in accordance with claim 1, wherein said inference engine decodes one subset of the plurality of control bits for selecting one of the set of input membership functions and decodes another subset of the plurality of control bits for selecting one of the set of output membership functions.

5. An appliance electronic control system for controlling at least a washing machine appliance having a tub which is filled to a predetermined water volume during operation and having a plurality of functional elements for implementing a plurality of appliance functions, said appliance electronic control system comprising:

an element for comparing a signal representing water volume to a predetermined water volume and discontinuing a water filling operation when the tub is filed to the predetermined water volume;

a fuzzy logic controller including;

at least one input for receiving an input value;

an output;

a configuration input for receiving definitions of at least one set of input membership functions corresponding to said at least one input, definitions of a set of output membership functions, and a set of inferencing rules each defined as a plurality of control bits;

memory elements for storing input membership function definitions, output membership function definitions and inferencing rules;

updating elements connected to said configuration input and to said memory elements for updating membership functions and inferencing rules in said memory elements while inferencing rules are being processed during operation of the fuzzy logic controller;

elements for calculating a degree of belief for each of the stored input membership functions based on the input value;

an inference engine operable, for each of the stored set of inferencing rules, to calculate a scaled value for a particular output membership function based on at least one input membership function degree of belief in accordance with control bits of the inferencing rule; and

elements for calculating a crisp value based on the calculated scaled values and for outputting the crisp value to said output; and

an element for supplying a pressure reading to said reconfigurable fuzzy logic controller as an input, the pressure reading representing water pressure at the bottom of the washing machine tub;

wherein said fuzzy logic controller is programmed to provide, as an output, the signal representing water volume for use by said element for discontinuing a water filling operation.

6. An appliance electronic control system in accordance with claim 5, which further comprises a communication link connected to said fuzzy logic controller for inputting membership function definitions and inferencing rules to be stored in said memory elements.

7. An appliance electronic control system in accordance with claim 5, which further comprises:

a controller including output lines for activating the functional elements within the appliance, memory elements for storing parameters, and control elements for effecting an appliance operational cycle comprising a sequence of operational modes, the predetermined water volume being determined based on a parameter stored in said memory elements, and said controller including said element for comparing and discontinuing a water filling operation; and

a communication link connected to said fuzzy logic controller and to said controller for inputting membership function definitions, inferencing rules and parameters to be stored in said memory elements of said fuzzy logic controller and of said controller.

8. An appliance electronic control system for controlling at least a clothes drying appliance having a plurality of functional elements including a duty cycle controlled heating element for implementing a plurality of appliance functions, said appliance electronic control system comprising:

a control element for the duty cycle controlled heating element;

a fuzzy logic controller including;

at least one input for receiving an input value;

an output;

a configuration input for receiving definitions of at least one set of input membership functions corresponding to said at least one input, definitions of a set of output membership functions, and a set of inferencing rules each defined as a plurality of control bits;

memory elements for storing input membership function definitions, output membership function definitions and inferencing rules;

updating elements connected to said configuration input and to said memory elements for updating membership functions and inferencing rules in said memory elements while inferencing rules are being processed during operation of the fuzzy logic controller;

elements for calculating a degree of belief for each of the stored input membership functions based on the input value;

an inference engine operable, for each of the stored set of inferencing rules, to calculate a scaled value for a particular output membership function based on at least one input membership function degree of belief in accordance with control bits of the inferencing rule; and

elements for calculating a crisp value based on the calculated scaled values and for outputting the crisp value to said output; and

elements for supplying an air temperature error signal and a rate of change of air temperature error signal to said fuzzy logic controller as inputs, the air temperature error signal representing the difference between measured air temperature within the clothes drying appliance during operation and a predetermined drying temperature;

wherein said fuzzy logic controller is programmed to provide, as an output, a signal for controlling the duty cycle of said heating element.

9. An appliance electronic control system in accordance with claim 8, which further comprises a communication link connected to said fuzzy logic controller for inputting membership function definitions and inferencing rules to be stored in said memory elements.

10. An appliance electronic control system in accordance with claim 9, which further comprises:

a controller including output lines for activating the functional elements within the appliance including said duty cycle controlled heating element, memory elements for storing parameters, and control elements for effecting an appliance operational cycle comprising a sequence of operational modes, the predetermined drying temperature being determined based on a parameter stored in said memory elements of said controller, the output of said fuzzy logic controller being connected to said controller; and

said communication link being further connected to said controller for inputting parameters to be stored in said memory elements of said controller.