Simulink Control Design™ - MathWorks

Validate Exact Linearization Results Using Estimated Frequency Response

Linearize a Simulink model and use frequency-response estimation to validate the exact

linearization results.

Open the watertank model.

model = 'watertank';

open_system(model);

Obtain a linearization of the open-loop response of the plant. To do so, define the

linearization I/O points, and find a steady-state operating point near the model initial

conditions. Then, linearize the model.

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

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

watertank_spec = operspec(model);

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

op = findop(model,watertank_spec,opOpts);

syslin = linearize(model,op,io);

To check the linearization, use the same analysis points and operating point to estimate

the frequency response. For this example, use a sinestream input signal for the

estimation.

input = frest.Sinestream('Frequency',logspace(-3,2,20));

sysest = frestimate(model,op,io,input);

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