Fault tolerant steer-by-wire reliability evaluation with mechanical backup

A fault tolerant steer-by-wire (SBW) system requires an operation procedure to cope with partial system degradations. This paper presents a reliability quantification method that converts the operation procedure into an augmented Markov transition diagram where each state represents either a normal SBW, or a partially degraded or a completely failed SBW. The system reliability is quantified in terms of the state probabilities calculated from a numerical integration of the Markov diagram specified by component failure rates. A structural design was already proposed and an example of operation procedure was derived in our previous study for a SBW system consisting of a principal SBW, a standby SBW and a mechanical backup hopefully with a power assist feature. The proposed method is demonstrated by an application to this SBW design. It turns out that the SBW system demonstrates a considerably high reliability through the introduction of mechanical backup. The power assist, however, is rarely available during the mechanical backup mode. This lack of power assist can be reduced by increasing reliability of ECU (Electronic Control Unit).

Authors:
- ZUO, G
- KUMAMOTO, H
- NISHIHARA, O
- HAYAMA, R
- NAKANO, S
Publication Date: 2008

Language

English

Media Info

Pagination: 85-90
Serial:
- INTERNATIONAL JOURNAL OF ITS RESEARCH
- Volume: 2
- Issue Number: 1

Subject/Index Terms

TRT Terms: Deterioration; Evaluation; Mechanical failure; Mechanics; Motor vehicles; Significance (Statistics); Steering; Steering columns; Tests
ITRD Terms: 1684: Breakdown (veh); 5255: Deterioration; 9020: Evaluation (assessment); 5455: Mechanics; 6532: Significance (stat); 1834: Steering (process); 1309: Steering column; 6255: Test
Subject Areas: Vehicles and Equipment; I91: Vehicle Design and Safety;

Filing Info

Accession Number: 01109565
Record Type: Publication
Source Agency: Transport Research Laboratory
Files: ITRD
Created Date: Aug 25 2008 8:40AM