Estimate Frequency Response with Linearization-Based
Input Using Linear Analysis Tool
When you have a linear model representing the portion of your Simulink model that you
want to estimate, you can use that model to generate the input signal. This alternative to
manually specifying the estimation signal (as shown in “Estimate Frequency Response
Using Linear Analysis Tool” on page 5-7) can be useful when you are using frequency
response estimation to validate a model obtained through linearization. This example
shows how to perform frequency response estimation in Linear Analysis Tool using an
input signal that is based on the dynamics of an exact linearization of the model.Linearize Simulink ModelIn this example, linearize a Simulink model to obtain the linear model you use to generate
the estimation input signal.(^1) Open the Simulink model.
sys = 'scdDCMotor';
open_system(sys)
This model contains predefined linear analysis points. There is an input point at the
compensator output and an open-loop output after the unit gain block. The response
from the defined input to the defined output is the response of the inner loop of the
model, with the outer loop open.
(^2) In the Simulink Editor, select Analysis > Control Design > Linear Analysis.
(^3) Linearize the model using the predefined analysis points and using the model initial
conditions as the operating point.
Estimate Frequency Response with Linearization-Based Input Using Linear Analysis Tool