Download function evaluation mode

SECTION 3
FUNCTION EVALUATION,
CO-SIMULATION PERFORMANCE
ADM711, Section 3, January 2013
Copyright© 2013 MSC.Software Corporation
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OVERVIEW
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Investigate Function Evaluation mode, compare results quality
to co-simulation mode. Explore co-simulation performance as
simulation parameters are altered.
ADM711, Section 3, January 2013
Copyright© 2013 MSC.Software Corporation
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FUNCTION EVALUATION MODE
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Function evaluation (or continuous) mode lets the MATLAB (or
EASY5) integrators solve the entire problem made up of the
Adams equations and the MATLAB (EASY5) equations. In this
mode, Adams simply acts as a ‘function evaluator’ for the
MATLAB (EASY5) integrator.
Mode
Integrators used
Co-simulation
MATLAB and Adams
Function Evaluation
ADM711, Section 3, January 2013
Copyright© 2013 MSC.Software Corporation
Comments
MATLAB solves Simulink model, Adams/Solver
solves Adams model. Data exchanged periodically.
MATLAB solves both Simulink and Adams models.
Adams/Solver just acts as function evaluator for
MATLAB integrator.
MATLAB
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FUNCTION EVALUATION MODE
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Limitations of the method:
– Adams/Solver is often better at solving complicated Adams
models, especially with entities like CONTACTs. Co-simulation is
therefore, often more robust.
– Function Evaluation mode does not work with most Adams/Car
(Adams/Engine, Adams/Driveline, etc.) models as the
CONTROL/ statement is not supported in continuous mode.
ADM711, Section 3, January 2013
Copyright© 2013 MSC.Software Corporation
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TCP/IP COMMUNICATION
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Traditional communication method for Adams/Controls:
– ‘Named pipe’ files - basically input/output file buffers.
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Alternative communication method:
– TCP/IP communication - uses network infrastructure found in all
modern computer Operating Systems.
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Advantages of TCP/IP communication method:
– MATLAB (EASY5) and Adams do not need to be on the same
machine: can be run across a network. In reality, though, this is
not encouraged as it is quite slow!
ADM711, Section 3, January 2013
Copyright© 2013 MSC.Software Corporation
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TCP/IP COMMUNICATION
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Additional setup required for using the TCP/IP communication
method:
– The ‘Adams Daemon’ must be started by either method:
1.Manually: copy the ‘adams_daemon.py’ file from the
Adams/Controls installation directory to your working directory
and then start is using ‘adams2012_x64 python
adams_daemon.py’.
2.From within MATLAB, issue command:
‘start_adams_daemon’
– The TCP/IP communications method must be chosen in the
Adams plant mask (MATLAB) or the component data table
(EASY5).
ADM711, Section 3, January 2013
Copyright© 2013 MSC.Software Corporation
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CO-SIMULATION PERFORMANCE SETTINGS
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To save less data in Adams:
– By default, each communication interval generates output data
for the Adams output files (*.req, *.res, *.gra) during a cosimulation. Adams/Controls can save every nth sample using
the ‘Number of communications per output step’ parameter in
the MATLAB plant mask.
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Use ‘batch’ animation mode, avoid ‘interactive’ mode:
– Interactive mode uses Adams/View, while batch mode uses
Adams/Solver. The smaller resource overhead of Adams/Solver
generally leads to faster simulation times.
ADM711, Section 3, January 2013
Copyright© 2013 MSC.Software Corporation
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CO-SIMULATION PERFORMANCE SETTINGS
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Disable interactive charts or similar elements in Simulink (or
EASY5).
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Use a coarser sampling rate:
– This will speed up co-simulations, typically at the expense of
solution precision.
ADM711, Section 3, January 2013
Copyright© 2013 MSC.Software Corporation
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