Knowledge-Based Diagnostic System for a Complex Technical System, Comprising Two Separate Knowledge Bases for Processing Technical System Data and Customer Complaints

• US 20070226540A1
• Filed: 05/04/2005
• Published: 09/27/2007
• Est. Priority Date: 05/15/2004
• Status: Abandoned Application

• Current Assignee: Daimler AG (Mercedes-Benz Group AG)
• Original Assignee: Daimler Chrysler Company LLC (Stellantis NV)
• Inventors: Konieczny, Martin
• Application Number:
  US11/596,456
• Publication Number:
  US 20070226540A1
• Time in Patent Office: Days
• US Class Current: 714/26
• CPC Class Codes: G05B 2223/04 Detection of intermittent failure
• 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

Abstract

The present document describes a diagnostic system for localizing faults in diagnostics in a workshop. The diagnostic system takes into account both trivial and costly intermittent fault situations. It is characterized by a structured module concept for the software architecture. Division into localization of quasi-steady-state and intermittent faults is carried out by reference to classification of the diagnostic tasks. The first-mentioned problems can be solved by means of a systematic procedure using all the available information. The modular software architecture with strict separation of protected data and imprecise information supports the guided troubleshooting process. Current methods which operate according to the prior art are used in individual modules of the software architecture. The advantages of the known system diagnostics, such as compression of the suspected components are utilized and expanded. The inventive addition of symptom processing improves the result of previous systems for system diagnostics. The improved guidance during the system diagnostics helps to avoid removing satisfactory components. Generation of dynamic test step trees is innovatively used for efficient fault localization. In the known system diagnostics, intermittent faults give rise to long troubleshooting times owing to the necessary reproducibility of the fault. The diagnostic system according to the invention supports the localization of the intermittently occurring faults by also logging in temporary onboard diagnostics or temporary remote diagnostics with subsequent evaluation in the workshop. The significant advantage of this method is the fact that the customer is not deprived of his vehicle during the fault localization process.

Claims

1. A computer-supported diagnostic system for technical devices having a runnable diagnostic program,

which uses an implemented evaluation algorithm to collect fault-specific technical system data relating to the technical device to be analyzed,

which uses the evaluation algorithm to evaluate and interpret the collected technical system data using a computer-processable model of the technical device and using a technical knowledge base in which the rule-based diagnostic knowledge relating to the technical device to be analyzed is stored for the computer-processable model, and arrives at a diagnostic decision, the diagnostic decision containing a first set of fault candidates which indicates which parts of the technical device are suspected to be faulty,

characterized in that fault symptoms which are observed with a man-machine interface are registered and mapped onto a current, model-based symptom tree,

and in that the evaluation algorithm evaluates and interprets the symptoms of the current standardized symptom tree using system processing and a second symptom-based knowledge base, and determines a second set of fault candidates.

2. The diagnostic system as claimed in claim 1, characterized in that at least one of the two sets of fault candidates for the individual fault candidates contains both attribution features and discounting features.

3. The diagnostic system as claimed in claim 1, characterized in that the fault symptoms are determined from a customer complaint.

4. The diagnostic system as claimed in claim 1, characterized in that the evaluation algorithm sets off the first and second sets of fault candidates against one another.

5. The diagnostic system as claimed in claim 4, characterized in that during the setting off of first and second sets of fault candidates those fault candidates which contain discounting features are excluded.

6. The diagnostic system as claimed in claim 4, characterized in that during the setting off of first and second sets of fault candidates the average set of the two sets of fault candidates is determined.

7. The diagnostic system as claimed in claim 1, characterized in that prioritization is carried out for the fault candidates.

8. The diagnostic system as claimed in claim 1, characterized in that a test step tree is created for the set of fault candidates which is determined.

9. The diagnostic system as claimed in claim 1, characterized in that the structure of the diagnostic system can be expanded with further evaluation algorithms and knowledge bases.

10. The diagnostic system as claimed in claim 1, characterized in that a further set of fault candidates is determined using a remedy system (tips/news).

11. The diagnostic system as claimed in claim 8, characterized in that the test step tree is created from test step primitives.

12. The diagnostic system as claimed in claim 1, characterized in that a further knowledge base relating to the history of the vehicle is included by the evaluation algorithm in the determination of the set of fault candidates.