Otto-von-Guericke-Univ. Magdeburg
Vorlesung « Messtechnik »
What is Simulink? (1/2)
¾Simulink : is an extension (toolbox) of Matlab, and must
therefore be started from the Matlab prompt >>
Introduction to Simulink
¾Allows to access all the instructions of Matlab, but adds on
top of it a wealth of specific tools to simulate and control in a
realistic manner dynamic systems
Dominique Thévenin, Gábor Janiga
¾Simulink is found at many universities but also in industrial
companies (real-time control, determination of working
parameters for Engines or Gas Turbines...)
Lehrstuhl für Strömungsmechanik und
Strömungstechnik (LSS)
¾This is only the shortest possible introduction, please consult
the documentation for more details!
thevenin@ovgu.de, janiga@ovgu.de
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What is Simulink? (2/2)
¾Simulink can be used to carry out virtual experiments, for
example to prepare later experiments; or to acquire real
experimental data, like LabView (Real-Time Toolbox needed). 2
Working with Simulink (1/3)
¾Simulink uses a (graphical) representation based on blockdiagrams to describe dynamic (i.e. time-dependent) systems
¾To launch Simulink, just enter under the prompt Matlab >>
Î simulink
¾Any group of components can be associated and become a
single element, that can be used in further assemblies
Î in File menu, click New/Model to obtain a new work
window
¾For this purpose, inputs and outputs must be clearly defined
Î in the window Simulink you will find a quantity of
predefined working blocks
¾To get a first impression of Simulink, enter under the Matlab
prompt >> f14 (script f14.m is predefined):
Î click on individual blocks to open and explore sub-blocks
Î double-click e.g. on Sources: this opens a separate
window containing many standard « source » blocks, for
example signal generators
Î observe the connection between stick, incidence angle (in
radian) and acceleration on the pilot
Î choose e.g. the block Signal Gen by selecting it and
drawing it to your work window (Untitled)
Î to run: open the oscilloscopes, and click Simulation/Start3
Î in this way, you obtain an active copy of Signal Gen
Î this is a quite extensive model of a US-fighter F14
Working with Simulink (2/3)
Working with Simulink(3/3)
Î open the block Sinks (reception/acquisition of signals) :
opens a window containing many standard blocks useful to
get/acquire a signal and possibly represent the data
graphically in real-time
¾All block parameters can be controlled or modified by opening
the block (double-click or command bar)
¾ test Signal Gen and Scope
¾The axis extension of the Scopes can be modified by rightclicking on it
Î choose e.g. Scope (a standard oscilloscope) by selecting
it, and draw it to your work window
¾The parameters of the dynamic simulation can be modified
under the menu Simulation/Configuration Parameters
Î by clicking in the work window (Untitled) using the left
mouse button, you can connect the output of Signal Gen
to the input of Scope
¾You can save your work using the menu File/Save, using a
name terminated by .mdl (e.g. simplesimk.mdl)
Î open the oscilloscope by double-click
¾This "script" can now directly be executed under Matlab (no
need to start Simulink), or can be re-opened and modified under
Simulink using the menu File/Open
Î launch Simulation (default parameters) by clicking on
Simulation/Start
Î Start becomes Stop (for breaking the Simulation)
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Hands-on simk1
Hands-on simk2
¾Amplify the signal coming out of a generator and visualize the
original and the amplified signal (look under Math
Operations) simultaneously using two scopes. Test different
gains and check result.
right mouse button to split
Signal
scope 1
generator
¾Same purpose, but using this time a single scope and a
multiplexer (Mux, predefined in the Signal Routing library).
signal
generator
multiplexer
scope
scope 2
amplificator
with variable gain
amplificator
with variable gain
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Hands-on simk3
Matlab function
¾Same as previous but saving all the acquired data in a file for
later analysis (use predefined block To File in Sinks). Check
content of multi-column file. Check and modify simulation
parameters (accuracy, discretization step)!
signal
generator
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multiplexer
¾Similarly to the Matlab scripts, it is also possible to define
Matlab functions, involving a certain number of inputs and
outputs
¾These inputs and outputs are usually gathered in a single
vector
¾ Example for a basic function delivering output=2*first
argument-second argument
scope
function [result]=linear(arg1, arg2)
to file
result=2.*arg1-arg2;
end
amplificator
with variable gain
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Matlab function in Simulink
Virtual experiment
¾Any Matlab function can be directly integrated into a Simulink
script (use predefined block Matlab function). To input or
output vectors, use multiplexer/demultiplexer
signal
generator
multiplexer
multiplexer
Constant
=3
¾The script name must be the same as the function name, also
here linear.m
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¾In this final hands-on, you will develop by yourselves a
complete, virtual experiment
¾First, study with attention the distributed document: it is vital for
the success of your project!
¾Ask for support if needed, but AT LEAST when you have
obtained the coefficients of the matrix system to solve...
scope
Enjoy!
to data file
function
Matlab function
linear
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