Reasoning method and fault diagnosis method and system implementing the same

• US 5,412,802 A
• Filed: 05/06/1991
• Issued: 05/02/1995
• Est. Priority Date: 05/11/1990
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd., Hitachi Touhoku Software Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi, Ltd., Hitachi Touhoku Software Limited (Hitachi, Ltd.)
• Inventors: Fujinami, Tsutomu, Renge, Keiichiro, Tozuka, Kenji, Inoue, Kouji, Tsuji, Hiroshi, Moriyama, Kenzo
• Primary Examiner(s): Beausoliel, Jr., Robert W.
• Assistant Examiner(s): Snyder, Glenn
• Application Number:
  US07/695,928
• Time in Patent Office: 1,457 Days
• Field of Search: 371/15.1, 395/911, 395/912, 395/913, 395/914, 395/915, 395/916, 395/917, 395/918, 395/64, 395/575, 395/50, 395/51, 395/52, 364/274.3, 364/274.5
• US Class Current: 714/26
• CPC Class Codes: G01R 31/2846 using hard- or software simulation or using knowledge-based systems, e.g. expert systems, artificial intelligence or interactive algorithms
• CPC Class Codes: G06F 11/2257 using expert systems

Abstract

A reasoning method capable of easily describing a model of diagnosis, a diagnosis method based on the reasoning method and a fault diagnosis system for performing efficiently faulty component diagnosis. Basic knowledge of a domain for which a knowledge base is used, expert'"'"'s heuristic knowledge and meta-level knowledge for determining a scheme of use of the basic knowledge and the heuristic knowledge are provided. Fault diagnosis is performed for an objective of interest by executing a combination of reasoning based on the basic knowledge and reasoning based on the heuristic knowledge, in accordance with the meta-level knowledge.

Claims

1. A fault diagnosis method for specifically identifying a faulty component by using knowledge of fault diagnosis based on data expressing features or states of an objective under diagnosis, the method comprising the steps of:

providing problem localizing knowledge for identifying a faulty component based on an operation principle of said objective under diagnosis, heuristic knowledge for localizing the faulty component based on available expertise, and meta-level diagnosis knowledge for determining a scheme of using said problem localizing knowledge and said heuristic knowledge; and

,

executing a reasoning for the faulty component of said objective under diagnosis through a combination of a reasoning based on the use of said problem localizing knowledge and a reasoning based on the use of said heuristic knowledge in accordance with said meta-level diagnosis knowledge by localizing the faulty component by omitting intermediate steps involved in the diagnosis which are determined in accordance with said heuristic knowledge based on data obtained during the diagnosis;

determining applicability of said omitting;

providing a stepwise execution mode in which a diagnosis processing is interrupted every time execution of one diagnosis step has been completed;

providing a one-path execution mode in which the diagnosis processing is interrupted every time one faulty component has been identified;

providing an all-path execution mode in which the diagnosis processing is terminated when all faulty components have been identified;

providing flags for discriminatively indicating diagnosis steps executed in said one-path execution mode and diagnosis steps executed in said all-path execution mode in association with said problem localizing knowledge;

detecting a flag indicating that a given diagnosis step to be executed has previously been executed from said flags upon identifying a faulty component either in said one-path execution mode or said all-path execution mode; and

,

aborting execution of said given diagnosis step while regarding the result of said execution as being unsuccessful when the detecting occurs.

2. A fault diagnosis system comprising:

at least one problem localizing unit;

at least one shortcut reasoning unit; and

,

a meta level control unit;

wherein each problem localizing unit includes problem localizing knowledge and problem localizing means for identifying stepwise a faulty component convergently by using the problem localizing knowledge and data of an objective under diagnosis;

wherein each shortcut reasoning unit includes heuristic knowledge and shortcut reasoning means for localizing the faulty component by omitting intermediate steps of those involved in the diagnosis using the heuristic knowledge on faulty diagnosis;

wherein said meta-level control unit includes meta level diagnosis means for deciding whether said shortcut reasoning unit is to be activated or not;

wherein said at least one problem localizing unit is operable by a first processor dedicated thereto and including means for storing said problem localizing knowledge and said problem localizing means;

wherein said at least one shortcut reasoning unit is operable by a second processor dedicated thereto and including means for storing said heuristic knowledge and said shortcut reasoning means; and

,

wherein said problem localizing unit and said shortcut reasoning unit are controlled by said metal-level diagnosis means operable by a third processor provided separately from said first and second processors.