Simulink Control Design™ - MathWorks

Examples

Estimate Frequency Response of a Portion of a Simulink Model

Estimate the open-loop response of the plant in the watertank model. Open the model.

model = 'watertank';

open_system(model);

To estimate the open-loop response of the plant, define a linearization I/O set that

specifies this portion of the model with analysis points. Define an input analysis point at

the controller output, and define an open-loop output point at the plant output.

io(1)=linio('watertank/PID Controller',1,'input');

io(2)=linio('watertank/Water-Tank System',1,'openoutput');

Find a steady-state operating point for the estimation. For this example, use a steady-

state operating point derived from the model initial conditions.

watertank_spec = operspec(model);

opOpts = findopOptions('DisplayReport','off');

op = findop(model,watertank_spec,opOpts);

Create an input signal for estimation. For this example, use a sinestream signal, which

sends a series of separate sinusoidal perturbations at the frequencies you specify.

input = frest.Sinestream('Frequency',logspace(-3,2,30));

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