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Simulations
Dymola has been used
in many modeling and simulation applications. You will find examples
in the following selection of paper abstracts, links to other
papers and case studies.
Selection of paper
abstracts
Toyota Motor
Corporation
ABSTRACT
This
paper describes some usage examples of Dymola within Toyota. Dymola
has been used in many divisions, including Engine, Drivetrain, and
Chassis. In the Drivetrain division, acceleration performance and
noise vibration are being evaluated. In the Engine division, we
have constructed an Engine library for Diesel Engine Control. Using
the model, we have analyzed behavior of mass flow, pressure, and
temperature in all parts of the engine. In addition evaluation of
a designed control system was done.
"To
construct the drivetrain models, we have been mainly used Dymola.
For a simulation package, it is important that it is easy to construct
models. It is also important that a model once built is able to
be easily re-used. Therefore, Dymola is convenient because it has
a drivetrain library, and if the library doesn't contain a model
which we need, we can make the necessary model easily."
Toyota Motor
Corporation
ABSTRACT
The
HILS (Hardware In the Loop Simulation) is a popular technique to
debug control logic of vehicles. Previously, only simplified models
could be used to achieve real time performance in the simulations.
On the other hand, quite detailed models of engine, drivetrain,
hydraulics and brake system were developed with Dymola in recent
years. Therefore we would like to use these models also in HILS.
However, real time is difficult to obtain for stiff model components,
such as the hydraulics, because integrators with fixed step size
must be used. With explicit methods very small step sizes are needed
to ensure stability. With implicit methods large nonlinear systems
of equations have to be solved. Both approaches seem to be not feasible.
To improve this situation, the new inline and mixed mode integration
technique introduced by Dymola is evaluated for an engine model
and results are reported.
BMW AG
ABSTRACT
In
this article, hardware-in-the-loop (HIL) simulation of a passenger
car automatic gearbox is discussed. The simulation includes detailed
models of the mechanics and hydraulics and less detailed models
of the other parts of the car's drive train like its engine, torque
converter, differential gearbox, chassis and driving resistances.
After a short description of the components to be modeled, special
issues of simulating variable structure mechanical systems (coupled
frictional elements), simulating hydraulics and simulating in real
time with the gearbox control electronics hardware in the loop are
discussed. A simulation based, detailed assessment of the dynamics
of the gearbox hydraulics show that it might be modeled (under certain
assumptions) with fixed causality without major loss of accuracy.
Therefore nonlinear systems of equations in the hydraulic parts
of the model can be avoided. This enables the usage of a model based
on hydraulic component submodels, rather than on overall global
dynamics to be used for real time simulations with standard HILsimulation
hardware. The article ends with a short discussion of HIL-simulation
results and an outlook on future work.
Ford Motor
Company
ABSTRACT
In
order to comply with increasing consumer and regulatory demand for
improved fuel economy and lower emissions, Ford Motor Company is
developing a Hybrid Electric Vehicle (HEV) version of the Escape
sport utility vehicle for production in 2003. Since HEVs typically
have several different operating modes (e.g. electric launch, active
neutral, regenerative braking), an important concern is the fact
that each of these modes and the transitions between them lead to
minimal driver perceived vibrations. In order to understand how
the design and control of an HEV influences what is "felt" by the driver, we need to build models that accurately reproduce
the dynamic response of the power-train. In this way, the response
for a given mechanical configuration and/or controller design can
be evaluated.
A
model targeted at prediction of driver perceived vibration was developed
and validated against experimental data. However, one unexpected
result of this work was to demonstrate that we could take the dynamic
model used to reproduce the behavior described previously and, by
using some advanced Modelica features, derive a second model that
predicts the system efficiency of the transmission without having
to create an entirely new model for that purpose. The system efficiency
model was also validated against experimental data and showed very
good agreement. The result is that rather than spending time creating
and maintaining two different models (one for dynamic response and
one for system efficiency) we were able to build one on the foundation
of the other. Furthermore, we determined it was possible to generate
a single model that could describe both types (i.e. dynamic and
steady-state) of responses by merely changing the values of a few
model parameters.
ZF Friedrichshafen
ABSTRACT
It
is shown how to model and simulate frictional effects present in
gearboxes and in planetary gearboxes. This includes modeling of
gear wheel stucking and sliding due to Coulomb friction between
the gear teeth leading to load torque dependent losses. This allows
reliable simulation of, e. g., stick-slip effects in servo drives
or gear shifts in automatic gearboxes. It is also discussed how
the friction characteristics can be measured in a useful way. The
presented models are implemented in Modelica and demonstrated at
hand of the simulation of an automatic gearbox.
Scania
ABSTRACT
Models
that can be used to analyse the fuel consumption of auxiliary units
in heavy vehicles are presented. With the purpose of evaluating
the influence from various drive concepts and control principals,
a model library is developed in the modelling language Modelica.
The library contains a mixture of models developed from physicalprinciples
and models fitted to collected data. Modelling of the cooling system
is described in some detail. Simulation results are compared with
measurement data from tests in a wind tunnel.
Publications
A list of
Dymola and Modelica related papers is available here.
Case
studies
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