User`s guide

Release 7.5 MADYMO Coupling Manual

start with Finite Element models. Then, the states should be computed by the MADYMO

implicit-explicit Euler integrator in MADYMO.

• The variable time step MATLAB (and MADYMO) solvers are not implemented for the

MATLAB/ Simulink coupling, because the integration time step is not updated in MA-

DYMO.

• Only zero or one input/output ports are omitted. Both the input port width and the

output port width should match the MADYMO model.

• During the termination phase of the Simulink model the platform ’win32p’ and ’em64t-

win’ will continue, where the other platforms wait on the completion of the termination

phase of MADYMO.

• For MATLAB running on Windows, batch processing can be used only if matlab.bat is

started in combination with the option -wait. See the MATLAB manual pages for further

documentation.

• The port used for the TCP/IP connection are not always available for the next simulation,

since they might be locked by the system. The update time of the system administration

can take quite some time.

• MADYMO information may be shown in the command screen of MATLAB during the

coupled simulation. However all MADYMO related output ﬁles, including the LOG ﬁle

are available separately.

• Errors in the MADYMO model will result in an error during the start of the Simulink

model. An error message for the S-function block madymo3d_server will explain the

type of error. For a detailed error message the LOG and/or REPRINT ﬁle should be

examined.

• On linux, the MATLAB (environment) might cause abnormal termination during the

parsing of the MADYMO input ﬁle. This is solved by setting the LD_PRELOAD envi-

ronment variable of the gcc library.

setenv LD_PRELOAD /lib/libgcc_s.so.1

Here are some MADYMO known issues:

• Since MATLAB leads the integration, the MB time step can not be changed during the

simulation. The coupling with an external FE program is not supported.

• The stability of MADYMO is not only related to the parameters deﬁned in the MADY-

MO model, but also related to the Simulink model when a closed control loop (feedback)

is deﬁned.

• Locking and unlocking by Coulomb friction, breaking of joints and mass belts are not

allowed when using the MATLAB solver, because no reset of the states is implemented.

The MADYMO implicit-explicit Euler integrator can be used instead.