Civil Engineering Reference
In-Depth Information
• Type of topology
• Physical interface of ECU and number of ECUs
• Cable type and length
The cumulative impact of these elements is so complex that it is impossible to
manually predict the electrical behaviour of a vehicle topology and analyse its ro-
bustness through a pure paper specification. This is particularly important during
the specification phase since any problems discovered during the later stages of
development can be very costly to correct. This problem is even more severe if
problems related to network implementation are uncovered close to the start of pro-
duction (SOP) and the timely delivery of the vehicle to market is at risk.
Aside from the complexity, the huge diversity of vehicle platforms related to
different sets of vehicle equipment adds another dimension to the challenge. It
is necessary to ensure that the network implementation of all variants associated
with each vehicle platform function properly. However, the effort to test all vari-
ants would be tremendously high and time consuming and in some cases not even
feasible since certain dedicated variant types are not available for physical testing
before SOP.
Since vehicles are exposed to harsh environmental conditions in everyday opera-
tion, it must be ensured that the communication network functions robustly over
all of these possible operating conditions. Testing this would mean running the
tests under authentic and repeatable environmental conditions. These may relate to
temperature, vehicle component tolerances, cable impedance variations, etc. Tra-
ditional tests using a real vehicle prototype typically only allow for quite limited
coverage of the previously mentioned criteria and thus make it difficult to reach a
final conclusion about the robustness of the vehicle topology.
2.3.2
System Simulation as a Tool for Network Developers
To meet the growing demands and challenges that network developers face, simu-
lation-based approaches have become the preferred and dominant methodologies.
Initially, semiconductor companies adopted simulation methodologies but nowa-
days automotive original equipment manufacturer (OEMs) and their Tier 1 sup-
pliers have understood the necessity and benefits of a “virtual prototyping”-based
development approach. As opposed to the classic approach of designing the net-
work topology on paper and then later realizing it as a physical prototype (e.g.
breadboard) for testing purposes, the virtual prototyping approach allows one to
create an executable specification by means of a simulation model. The benefits of
using this methodology include the following:
• Proof of-concept of the topology specification without a physical prototype.
• Flexible adjustment of topology specification to explore different implementa-
tion options.
• Analysis of dedicated operating conditions and reproducible test results.
• Reduction of cost through optimization and accelerated test procedures.
