Simulink Control Design™ - MathWorks

Frequency Response Estimation Using Simulation-Based

Techniques

This example shows how to obtain the frequency response of Simulink models when

analytical block-by-block linearization does not provide accurate answer due to event-

based dynamics in the linearization path. Examples of such systems are models with

triggered subsystems or models using Pulse Width Modulation(PWM) input signals.

Step 1: Opening the Model

Open the Simulink model for engine timing. Note that analytical block-by-block

linearization of this model from throttle angle to engine speed gives a linearization result

of zero due to the triggered subsystem "Compression" in the linearization path.

scdengine

mdl = 'scdengine';

io = getlinio(mdl);

linsys = linearize(mdl,io)

linsys =

D =

ThrottleAngl

EngineSpeed 0

Static gain.

Frequency Response Estimation Using Simulation-Based Techniques