Method and system for determining a fault tree of a technical system, computer program product and a computer readable storage medium

• US 7,017,080 B1
• Filed: 05/26/2000
• Issued: 03/21/2006
• Est. Priority Date: 06/02/1999
• Status: Expired due to Term

• Current Assignee: IP Edge LLC
• Original Assignee: Siemens AG
• Inventors: Liggesmeyer, Peter, Rothfelder, Martin, Maeckel, Oliver, Rettelbach, Michael
• Primary Examiner(s): Bonzo, Bryce P.
• Application Number:
  US09/979,840
• Time in Patent Office: 2,125 Days
• Field of Search: 714/26, 714/47
• US Class Current: 714/26
• CPC Class Codes: G05B 23/0248 Causal models, e.g. fault tree; digraphs; qualitative physics
• CPC Class Codes: G05B 23/0278 Qualitative, e.g. if-then rules; Fuzzy logic; Lookup tables; Symptomatic search; FMEA
• CPC Class Codes: G06F 11/008 Reliability or availability analysis
• CPC Class Codes: G06F 11/2257 using expert systems

Abstract

The faults are described using a fault description which comprises data which have been determined using failure modes and effects analysis. The fault description is extended by information regarding the dependency of possible faults and the frequency of occurrence of said faults. The extended fault description is used to ascertain, for a prescribed fault event, the fault tree and the frequency of occurrence of the fault event.

Claims

1. A method for determining a fault tree for a technical system, using a computer, comprising:

describing faults which can occur in the technical system, using a fault description, the fault description comprising data which have been determined using failure modes and effects analysis,

extending the fault description by information regarding the dependency of possible faults on one another and the frequency of occurrence of said possible faults, to thereby form an extended fault description,

using the extended fault description to determine, for a prescribed fault event, the fault tree describing the dependencies of possible faults which can lead to the fault event, and the frequency of occurrence of the fault event.

2. The method as claimed in claim 1, wherein the fault tree is determined from the extended fault description for the fault event in the following manner:

the fault event is taken as a basis for determining all the possible faults which can lead to the fault event on a descending hierarchical level of the fault description until elemental faults which themselves can no longer be caused by other faults have been determined for all faults,

for each elemental fault, the frequency of occurrence of the elemental fault is determined, and

on the basis of the frequencies of occurrence of the elemental faults, the frequency of occurrence of the fault event is determined.

3. The method as claimed in claim 1, used for fault analysis in the technical system.

4. The method as claimed in claim 1, wherein the fault tree is altered in terms of prescribable boundary conditions.

5. The method as claimed in claim 4, wherein the alteration is made by adding a complementary fault tree.

6. The method as claimed in claim 2, used for fault analysis in the technical system.

7. The method as claimed in claim 6, wherein the fault tree is altered in terms of prescribable boundary conditions.

8. The method as claimed in claim 7, wherein the alteration is made by adding a complementary fault tree.

9. A system for ascertaining a fault tree for a technical system, comprising:

a description unit to describe faults which can occur in the technical system using a fault description, the fault description comprising data which have been determined using failure modes and effects analysis,

an extender to extend the fault description by information regarding the dependency of possible faults on one another and the frequency of occurrence of said faults, the extender producing an extended fault description,

a fault tree unit to determine the fault tree for a prescribed fault event, using the extended description, the fault tree describing the dependencies of possible faults which can lead to the fault event, and the frequency of occurrence of the fault event.

10. The system as claimed in claim 9, wherein the fault tree is determined from the extended fault description for the fault event in the following manner:

the fault event is taken as a basis for determining all the possible faults which can lead to the fault event on a descending hierarchical level of the fault description until elemental faults which themselves can no longer be caused by other faults have been determined for all faults,

for each elemental fault, the frequency of occurrence of the elemental fault is determined, and

on the basis of the frequencies of occurrence of the elemental faults, the frequency of occurrence of the fault event is determined.

11. The system as claimed in claim 9, used for fault analysis in the technical system.

12. The system as claimed in claim 9, wherein the processor is set up such that the fault tree is altered in terms of prescribable boundary conditions.

13. The system as claimed in claim 12, wherein the processor is set up such that the alteration is made by adding a complementary fault tree.

14. The system as claimed in claim 10, used for fault analysis in the technical system.

15. The system as claimed in claim 14, wherein the processor is set up such that the fault tree is altered in terms of prescribable boundary conditions.

16. The system as claimed in claim 15, wherein the processor is set up such that the alteration is made by adding a complementary fault tree.

17. A computer-readable medium storing a program for controlling a computer, to perform a method for determining a fault tree for a technical system, the method comprising:

describing faults which can occur in the technical system, using a fault description, the fault description comprising data which have been determined using failure modes and effects analysis,

extending the fault description by information regarding the dependency of possible faults on one another and the frequency of occurrence of said possible faults, to thereby form an extended fault description,

using the extended fault description to determine, for a prescribed fault event, the fault tree describing the dependencies of possible faults which can lead to the fault event, and the frequency of occurrence of the fault event.