Fuzzy inference apparatus with membership function adjustment

• US 5,251,288 A
• Filed: 08/26/1991
• Issued: 10/05/1993
• Est. Priority Date: 09/03/1990
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Hayashi, Isao, Nomura, Hiroyoshi, Wakami, Noboru
• Primary Examiner(s): MacDonald, Allen R.
• Application Number:
  US07/750,120
• Time in Patent Office: 771 Days
• Field of Search: 395/900, 395/61, 395/3, 395/51
• US Class Current: 706/12
• CPC Class Codes: G06N 7/023 Learning or tuning the parameters of a fuzzy system
• CPC Class Codes: Y10S 706/90 Fuzzy logic

Abstract

The fuzzy inference apparatus is provided to effect the tuning operation of the fuzzy inference with the use of the descent steps from the input/output data to be obtained from the specialists, the inputs of the users, and to automatically produce the desired fuzzy inference rules not by the trial and error, whereby the optimum inference rule can be obtained by the descent steps, and the specialists'"'"' knowledge and khow-how can be easily mounted on the appliances as the inference rules.

Claims

1. A fuzzy inference system comprising:

a controlled machine for operating in accordance with control input values and for producing control observation values responsive to an operation thereof; and

,

a fuzzy inference apparatus, coupled to said controlled machine, including

(a) an inference computing portion for effecting a fuzzy inference operation based on the control input values and corresponding control observation values of said controlled machine so as to generate an operation amount with respect to said controlled machine,

(b) an inference rule memory portion for storing inferences rules used in said inference computing portion,

(c) a membership function memory portion for storing geometric data of membership functions of antecedent parts and functions of consequent parts of each inference rule used in said inference computing portion,

(d) a descent method computing portion for effecting a descent method computing operation according to input/output data provided in advance and the operation amount generated by said inference computing portion,

(e) a membership function adjusting portion for varying at least one of the membership functions of the antecedent parts and the functions of the consequent part stored in said membership function memory portion in accordance with an output of said descent method computing portion,

(f) an error computing portion for computing an inference error from the input/output data and the operation amount generated by said inference computing portion, and for ceasing operations of said descent method computing portion and said membership function adjusting portion when at least one of the inference error and a change in the inference error satisfies a predetermined condition.

2. A fuzzy inference system comprising:

a controlled machine for operating in accordance with control input values and for producing control observation values responsive to an operation thereof; and

,

a fuzzy inference apparatus, coupled to said controlled machine, including

(a) an inference computing portion for effecting a fuzzy inference operation based on the control input values and corresponding control observation values of said controlled machine so as to generate an operation amount with respect to said controlled machine,

(b) an inference rule memory portion for storing inferences rules used in said inference computing portion,

(c) an antecedent part memory portion for storing parameters denoting a geometry of membership functions of antecedent parts of each inference rule used in said inference computing portion,

(d) a consequent part memory portion for storing real numbers of membership functions of consequent parts of each inference rule used in said inference computing portion,

(e) an antecedent part descent method computing portion for effecting a descent method computing operation with respect to the parameter denoting the geometry of the membership functions of the antecedent parts from input/output data provided in advance and the operation amount generated by said inference computing portion,

(f) an antecedent part parameter adjusting portion for varying at least one of parameters denoting the geometry of the membership functions of the antecedent parts stored in said antecedent part memory portion in accordance with an output of said antecedent part descent method computing portion,

(g) a consequent part descent method computing portion for effecting a descent method computing operation with respect to the real numbers of the consequent parts from the input/output data provided in advance and the operation amount generated by said inference computing portion,

(h) a consequent part real number adjusting portion for varying at least one of the real numbers of the consequent parts stored in said consequent part real number memory portion in accordance with an output of said consequent part descent method computing portion,

(i) an error computing portion for computing an inference error from the input/output data and the operation amount generated by said inference computing portion, and for ceasing operations of said antecedent part descent method computing portion, said consequent part descent method computing portion, said antecedent part parameter adjusting portion and said consequent part real number adjusting portion when at least one of the inference error and a change in the inference error satisfies a predetermined condition.

3. A fuzzy inference system comprising:

a controlled machine for operating in accordance with a total operation amount and for producing control observation values responsive to an operation thereof;

a controller for generating a first operation amount of the controlled machine in accordance with control input values and the observation values of said controlled machine;

a differential computing portion for obtaining a differential amount of the control input values;

a fuzzy inference apparatus, coupled to said controller and to said differential computing portion, including

(a) an inference computing portion for effecting a fuzzy inference operation based on the control input values and the corresponding differential amount so as to generate a second operation amount with respect to said controlled machine,

(b) an inference rule memory portion for storing inferences rules used in said inference computing portion,

(c) a membership function memory portion for storing membership functions of antecedent parts and functions of consequent parts of each inference rule used in said inference computing portion,

(d) a descent method computing portion for effecting a descent method computing operation according to the first operation amount generated by said controller and the second operation amount generated by said inference computing portion,

(e) a membership function adjusting portion for varying at least one of the membership functions of the antecedent parts and the functions of the consequent parts stored in said membership function memory portion in accordance with an output of said descent method computing portion; and

,

an operation amount adding portion, coupled to said controller and to said fuzzy inference apparatus and to said controlled machine, for adding the first and second operation amounts respectively generated by said controller and said fuzzy inference apparatus and for applying a thus obtained total operation amount to said controlled machine.

4. A fuzzy inference system comprising:

a controlled machine for operating in accordance with control input values and for producing control observation values responsive to an operation thereof; and

,

a fuzzy inference apparatus, coupled to said controlled object, including

(a) an inference computing portion for effecting a fuzzy inference operation based on the control input values and corresponding control observation values of said controlled machine so as to generate an operation amount with respect to said controlled machine,

(b) an inference rule memory portion for storing inferences rules used in said inference computing portion,

(c) a membership function memory portion for storing geometric data of membership functions of antecedent parts and functions of consequent parts of each inference rule used in said inference computing portion,

(d) a user input portion for inputting user preferences with respect to the operation amount generated by said inference computing portion,

(e) a descent method computing portion for effecting a descent method computing operation according to the user preferences input by said user input portion and the operation amount generated by said inference computing portion,

(f) a membership function adjusting portion for varying at least one of the membership functions of the antecedent parts and the functions of the consequent parts stored in said membership function memory portion in accordance with an output of said descent method computing portion,

(g) an error computing portion for computing an inference error from input/output data provided in advance and the operation amount generated by said inference computing portion, and for ceasing operations of said descent method computing portion and said membership function adjusting portion when at least one of the inference error and a change in the inference error satisfies a predetermined condition.

5. A fuzzy inference system comprising:

a controlled machine for operating which operates in accordance with control input values and for producing control observation values responsive to an operation thereof; and

,

a fuzzy inference apparatus, coupled to said controlled object, including

(a) an inference computing portion for effecting a fuzzy inference operation based on the control input values and corresponding control observation values of said controlled machine so as to generate an operation amount with respect to said controlled machine,

(b) an inference rule memory portion for storing inferences rules used in said inference computing portion,

(c) a membership function memory portion for storing geometric data of membership functions of antecedent parts and functions of consequent parts of each inference rule used in said inference computing portion,

(d) a descent method computing portion for effecting a descent method computing operation according to input/output data provided in advance and the operation amount generated by said inference computing portion,

(e) a membership function adjusting portion for varying at least one of the membership functions of the antecedent parts and the functions of the consequent parts stored in said membership function memory portion in accordance with an output of said descent method computing portion,

(f) an error computing portion for computing an inference error from the input/output data and the operation amount generated by said inference computing portion, and for ceasing operations of said descent method computing portion and said membership function adjusting portion when at least one of the inference error and a change in the inference error satisfies a predetermined condition, and

(g) an inference rule display portion for retrieving the inference rules stored in said inference rule memory portion and the membership functions stored in said membership function memory portion and for displaying the inference rules including the membership functions.

6. A fuzzy inference system comprising:

a controlled machine for operating in accordance with control input values and for producing control observation values responsive to an operation thereof; and

,

a fuzzy inference apparatus, coupled to said controlled object, including

(a) an inference computing portion for effecting a fuzzy inference operation based on the control input values and corresponding control observation values of said controlled machine so as to generate an operation amount with respect to said controlled machine,

(b) an inference rule memory portion for storing inferences rules used in said inference computing portion,

(c) a membership function memory portion for storing geometric data of membership functions of antecedent parts and functions of consequent parts of each inference rule used in said inference computing portion,

(d) a descent method computing portion for effecting a descent method computing operation according to the operation amount generated by said inference computing portion,

(e) a membership function adjusting portion for varying at least one of the membership functions of the antecedent parts and the functions of the consequent parts stored in said membership function memory portion in accordance with an output of said descent method computing portion,

(f) an evaluation value computing portion for obtaining an evaluation value denoting a control property of said controlled machine from the observation values of said controlled machine, and for ceasing operations of said descent method computing portion and said membership function adjusting portion when the evaluation value satisfies a predetermined condition.