Fault diagnosis

• US 7,529,643 B2
• Filed: 06/19/2007
• Issued: 05/05/2009
• Est. Priority Date: 06/22/2006
• Status: Expired due to Fees

• Current Assignee: Scania CV AB (Volkswagen AG)
• Original Assignee: Scania CV AB (Volkswagen AG)
• Inventors: Nyberg, Mattias
• Primary Examiner(s): Lau; Tung S
• Assistant Examiner(s): Kundu; Sujoy K
• Application Number:
  US11/765,075
• Publication Number:
  US 20080189076A1
• Time in Patent Office: 686 Days
• Field of Search: 702/119, 702/183, 702/123, 702/182, 701/33, 717/136, 717/142, 717/143
• US Class Current: 702/182
• CPC Class Codes: G06F 11/2257 using expert systems

Abstract

Status estimation is determined for an entity having a plurality of components. An original disjunction of diagnostic expressions indicating at least one of a fault-free or at least one fault mode for at least one of the components is determined, which is then investigated against a set of diagnostic test results, and expressions that do not imply the test result are discarded. Further, for each statement in the test result, a joint diagnostic expression is generated representing a conjunction of the statement and the currently investigated diagnostic expression. Joint diagnostic expressions that imply one of the original diagnosis expressions are discarded. Otherwise, they are added to an updated disjunction of diagnostic expressions. All remaining diagnostic expressions in the temporary disjunction of diagnostic expressions are then added to the updated disjunction of diagnostic expressions, and a status report is produced.

Claims

1. A diagnosis engine for estimating a status of an entity with a plurality of components which each is assumed to be in a fault-free mode or be in exactly one of at least one fault mode, the diagnosis engine comprising:

a processing unit adapted to analyze test results; and

at least one storage area adapted to store diagnostic data in respect of the entity,

wherein said processing unit is adapted to;

receive an original disjunction of diagnostic expressions indicating at least one of said modes for at least one of said components,

receive first test results of a set of diagnostic tests in respect of the entity, the result of each test being a disjunction of statements wherein each statement indicates at least one of said modes for one of said components,

store the expressions in the original disjunction of diagnostic expressions to a temporary disjunction of diagnostic expressions in a first storage area,

investigate, for each diagnostic expression in the temporary disjunction of diagnostic expressions, whether a currently investigated diagnostic expression implies the first test result;

if not so, remove the expression from the temporary disjunction of diagnostic expressions; and

, for each statement in the first test result,

generate a joint diagnostic expression representing a conjunction of the statement and the currently investigated diagnostic expression,

compare the joint diagnostic expression with each diagnostic expression in the original disjunction of diagnostic expressions except for the currently investigated diagnostic expression, and,

discard the joint diagnostic expression, if an original diagnostic expression is found, where the joint diagnostic expression implies the original diagnosis expression, or,

add the joint diagnostic expression to an updated disjunction of diagnostic expressions in a second storage area, if an original diagnostic expression is not found, the updated disjunction of diagnostic expressions representing an estimated status of the entity, thereafter

add all remaining diagnostic expressions in the temporary disjunction of diagnostic expressions to the updated disjunction of diagnostic expressions, and

produce a status report based on the updated disjunction of diagnostic expressions.

2. The diagnosis engine according to claim 1, wherein after having processed a result of the first test of the set of diagnostic tests, the processing unit is adapted to, for each result of at least one second test of the tests:

investigate, for each diagnostic expression in the temporary disjunction of diagnostic expressions, whether or not a currently investigated diagnostic expression implies the result of the second test;

if not so, remove the expression from the temporary disjunction of diagnostic expressions; and

, for each statement in the result of the second test,

generate a joint diagnostic expression representing a conjunction of the statement and the currently investigated diagnostic expression,

compare the joint diagnostic expression with each diagnostic expression in the original disjunction of diagnostic expressions except for the currently investigated diagnostic expression, and,

discard the joint diagnostic expression, if an original diagnostic expression is found, where the joint diagnostic expression implies the original diagnosis expression, or,

add the joint diagnostic expression to the updated disjunction of diagnostic expressions in the second storage area, if an original diagnostic expression is not found, thereafter

add all remaining diagnostic expressions in the temporary disjunction of diagnostic expressions to the updated disjunction of diagnostic expressions, and

produce an updated status report based on the updated disjunction of diagnostic expressions.

3. A motor vehicle comprising a plurality of components and a diagnosis system adapted to estimate a status of at least a sub-group of said components,

wherein the diagnosis system comprises a diagnosis engine comprising:

a processing unit adapted to analyze test results; and

at least one storage area adapted to store diagnostic data in respect of the motor vehicle,

wherein said processing unit is adapted to;

receive an original disjunction of diagnostic expressions indicating at least one mode for at least one of said components, wherein the at least one mode is a fault-free mode or one of at least one fault mode,

receive first test results of a set of diagnostic tests in respect of the motor vehicle, the result of each test being a disjunction of statements, wherein each statement indicates at least one of said modes for one of said components,

store the expressions in the original disjunction of diagnostic expressions to a temporary disjunction of diagnostic expressions in a first storage area,

investigate, for each diagnostic expression in the temporary disjunction of diagnostic expressions, whether a currently investigated diagnostic expression implies the first test result, if not so, remove the expression from the temporary disjunction of diagnostic expressions, and, for each statement in the first test result,

generate a joint diagnostic expression representing a conjunction of the statement and the currently investigated diagnostic expression,

compare the joint diagnostic expression with each diagnostic expression in the original disjunction of diagnostic expressions except for the currently investigated diagnostic expression, and,

discard the joint diagnostic expression if an original diagnostic expression is found, where the joint diagnostic expression implies the original diagnosis expression, or,

add the joint diagnostic expression to an updated disjunction of diagnostic expressions in a second storage area, if an original diagnostic expression is not found, the updated disjunction of diagnostic expressions representing an estimated status of the entity, thereafter

add all remaining diagnostic expressions in the temporary disjunction of diagnostic expressions to the updated disjunction of diagnostic expressions, and

produce a status report based on the updated disjunction of diagnostic expressions.

4. A method of diagnosing an entity with a plurality of components which each is assumed to be in a fault-free mode or be in exactly one of at least one fault mode, said method comprising:

receiving an original disjunction of diagnostic expressions indicating at least one of said modes for at least one of said components,

receiving a first test result of a set of diagnostic tests in respect of the entity, the result of each test being a disjunction of statements wherein each statement indicates at least one of said modes for one of said components,

storing the expressions in the original disjunction of diagnostic expressions to a temporary disjunction of diagnostic expressions in a first storage area,

investigating, for each diagnostic expression in the temporary disjunction of diagnostic expressions, whether a currently investigated diagnostic expression implies the first test result;

if not so, remove the expression from the temporary disjunction of diagnostic expressions; and

, for each statement in the first test result,

generating a joint diagnostic expression representing a conjunction of the statement and the currently investigated diagnostic expression,

comparing the joint diagnostic expression with each diagnostic expression in the original disjunction of diagnostic expressions except for the currently investigated diagnostic expression, and,

discarding the joint diagnostic expression if an original diagnostic expression is found, where the joint diagnostic expression implies the original diagnosis expression, or,

adding the joint diagnostic expression to an updated disjunction of diagnostic expressions in a second storage area, if an original diagnostic expression is not found, the updated disjunction of diagnostic expressions representing an estimated status of the entity, thereafter

adding all remaining diagnostic expressions in the temporary disjunction of diagnostic expressions to the updated disjunction of diagnostic expressions, and

producing a status report based on the updated disjunction of diagnostic expressions.

5. The method according to claim 4, wherein receiving an original disjunction of diagnostic expressions further comprises receiving an original disjunction of diagnostic expressions that is empty prior to receiving the first test result of the set of diagnostic tests of the entity.

6. The method according to claim 4, wherein after having processed a result of the first test in the test result, the method comprises, for each result of at least one second test in the test result:

investigating, for each diagnostic expression in the temporary disjunction of diagnostic expressions, whether a currently investigated diagnostic expression implies the result of the second test;

if not so, remove the expression from the temporary disjunction of diagnostic expressions; and

, for each statement in the result of the second test,

generating a joint diagnostic expression representing a conjunction of the statement and the currently investigated diagnostic expression,

comparing the joint diagnostic expression with each diagnostic expression in the original disjunction of diagnostic expressions except for the currently investigated diagnostic expression, and,

discarding the joint diagnostic expression, if an original diagnostic expression is found, where the joint diagnostic expression implies the original diagnosis expression, or,

adding the joint diagnostic expression to the updated disjunction of diagnostic expressions in a second storage area, if an original diagnostic expression is not found, thereafter

adding all remaining diagnostic expressions in the temporary disjunction of diagnostic expressions to the disjunction of diagnostic expressions, and

producing an updated status report based on the updated disjunction of diagnostic expressions.

7. A computer program product, comprising:

a computer-readable medium comprising;

a first set of codes for causing a computer to receive an original disjunction of diagnostic expressions indicating at least one mode for at least one of a plurality of components including in an entity, wherein the at least one mode is a fault-free mode or one of at least one fault modes;

a second set of codes for causing the computer to receive first test results of a set of diagnostic tests in respect of the entity, the result of each test being a disjunction of statements, wherein each statement indicates at least one of the modes for one of said components;

a third set of codes for causing the computer to store the expressions in the original disjunction of diagnostic expressions to a temporary disjunction of diagnostic expressions in a first storage area;

a fourth set of codes for causing the computer to investigate, for each diagnostic expression in the temporary disjunction of diagnostic expressions, whether a currently investigated diagnostic expression implies the first test result;

a fifth set of codes for causing the computer, if the currently investigated diagnostic expression does not imply the first test result, to remove the expression from the temporary disjunction of diagnostic expressions and, for each statement in the test result;

a sixth set of codes for causing the computer to generate a joint diagnostic expression representing a conjunction of the statement and the currently investigated diagnostic expression;

a seventh set of codes for causing the computer to compare the joint diagnostic expression with each diagnostic expression in the original disjunction of diagnostic expressions except for the currently investigated diagnostic expression;

a eighth set of codes for causing the computer, to discard the joint diagnostic expression, if an original diagnostic expression is found, where the joint diagnostic expression implies the original diagnosis expression, or add the joint diagnostic expression to an updated disjunction of diagnostic expressions in a second storage area, if an original diagnostic is not found, the updated disjunction of diagnostic expressions representing an estimated status of the entity;

a ninth set of codes for causing the computer to add all remaining diagnostic expressions in the temporary disjunction of diagnostic expressions to the updated disjunction of diagnostic expressions; and

a tenth set of codes for causing the computer to produce a status report based on the updated disjunction of diagnostic expressions.

8. The computer program product of claim 7, wherein the first set of codes of the computer-readable medium further comprises first set of codes for causing the computer to receive an original disjunction of diagnostic expressions that is empty prior to receiving the first test result of the set of diagnostic tests of the entity.

9. The computer program product of claim 7, wherein after having processed a result of the first test in the test result, for each result of at least one second test in the test result, wherein,

the fourth set of codes further causes the computer to investigate, for each diagnostic expression in the temporary disjunction of diagnostic expressions, whether a currently investigated diagnostic expression implies the second test result;

the fifth set of codes further causes the computer, if the currently investigated diagnostic expression does not imply the second test result, to remove the expression from the temporary disjunction of diagnostic expressions and, for each statement in the second test result;

the sixth set of codes further causes the computer to generate a joint diagnostic expression representing a conjunction of the statement and the currently investigated diagnostic expression;

the seventh set of codes further causes the computer to compare the joint diagnostic expression with each diagnostic expression in the original disjunction of diagnostic expressions except for the currently investigated diagnostic expression;

the eighth set of codes further causes the computer to discard the joint diagnostic expression, if an original diagnostic expression is found, where the joint diagnostic expression implies the original diagnosis expression, or add the joint diagnostic expression to an updated disjunction of diagnostic expressions in a second storage area, if an original diagnostic is not found, the updated disjunction of diagnostic expressions representing an estimated status of the entity;

the ninth set of codes further causes the computer to add all remaining diagnostic expressions in the temporary disjunction of diagnostic expressions to the updated disjunction of diagnostic expressions; and

the tenth set of codes further causes the computer to produce an updated status report based on the updated disjunction of diagnostic expressions.