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Abstract |
Distributed Fault Diagnosis for Networked Embedded Systems
In a system like a Scania heavy duty truck, faultcodes (DTCs) are
generated and stored locally in the ECUs when components, e.g. sensors
or actuators,malfunction. Tests are run periodically to detect failure
in the system. The test results are processed by the diagnostic system
that tries to isolate the faulty components and set local faultcodes. Currently, in a Scania truck, local diagnoses are only based on
local diagnostic information, which the DTCs are based upon. The
diagnosis statement can, however, be more complete if diagnoses from
other ECUs are considered. Thus a system that extends the local
diagnoses by exchanging diagnostic information between the ECUs is
desired. The diagnostic information to share and how it should be done
is elaborated in this thesis. Further, a model of distributed
diagnosis is given and a few distributed diagnostic algorithms for
transmitting and receiving diagnostic information are presented. A basic idea that has influenced the project is to make the
diagnostic system scalable with respect to hardware and thereby making
it easy to add and remove ECUs. When implementing a distributed
diagnostic system in networked real-time embedded systems, technical
problems arise such as memory handling, process synchronization and
transmission of diagnostic data and these will be discussed in
detail. Implementation of a distributed diagnostic system is further
complicated due to the fact that the isolation process is a non
deterministic job and requires a non deterministic amount of
memory.
Dan Hallgren and Håkan Skog
2005
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Senast uppdaterad: 2021-11-10
