Evaluation of Communication Interfaces for Electronic Control Units in Heavy-duty Vehicles
The number of electronic control units in heavy-duty vehicles has grown dramati-
cally over the last few decades. This has led to the use of communication buses to
reduce the complexity and weight of the networks. There are reasons to believe
that the de facto standard communication interface in the automotive industry,
the Controller Area Network, is obsolete in some areas. Hence an evaluation of
available communication interfaces is needed.
This study focuses on lower levels of the Open Systems Interconnect (osi) model.
Initially a theoretical study is presented in order to give an overview of auto-
motive embedded systems in general and different communication interfaces in
particular. Ethernet and FlexRay are identified as two interfaces of interest for
future use in Scanias vehicles. The former is new in automotive applications but
is believed to become popular over the years to come. A possible use of this in-
terface could be as a backbone to take the load off other interfaces. The use of
FlexRay in Scanias vehicles is limited because of the modular system used and
the static scheduling needed. It could however be used between mandatory ecus
where the nodes and the messages are all known beforehand.
The report also contains the result from emission measurements on a number of
interfaces performed using a stripline antenna in a shielded enclosure. Strong
conclusions can not be drawn since it’s hard to tell what the transceivers, cir-
cuit boards and interfaces contributed to in the spectra with the method used.
The FlexRay hardware is worse than for the other interfaces. Similarities can be
seen between low-speed and high-speed can but it could be characteristics of the
transceivers used rather than the interface itself.
Henrik Johansson
2012
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Last updated: 2021-11-10
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