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估计Frequency Response with Linearization-Based Input Using Model Linearizer

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估计Frequency Response Using Model Linearizer) 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 inModel Linearizerusing an input signal that is based on the dynamics of an exact linearization of the model.

Linearize金宝appModel

In 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 model window, in theAppsgallery, clickModel Linearizer.

  3. Linearize the model using the predefined analysis points and using the model initial conditions as the operating point.

    On theLinear Analysistab, clickBode.

    A new linearized model,linsys1, appears in theLinear Analysis Workspace.

Create Sinestream Input Signal

  1. On theEstimationtab, in theInput Signaldrop-down list, selectSinestream.

  2. Initialize the input signal frequencies and parameters based onlinsys1.

    In the Create sinestream input dialog box, clickInitialize frequencies and parameters.

    The frequency content viewer is populated with frequency points. The software chooses the frequencies and input signal parameters automatically based on the dynamics oflinsys1. The software also automatically initializes other parameters of the sinestream signal, including:

    • Amplitude

    • Number of periods

    • Settling periods

    • Ramp periods

    • Number of samples at each period

  3. Select all the frequency points.

  4. Specify the amplitude of the input signal.

    Enter1in theAmplitudebox.

  5. Create the input sinestream signal.

    ClickOK. The input signalin_sine1appears in theLinear Analysis Workspace.

估计Frequency Response

ClickBode Plot 1to estimate the frequency response.

The estimated system,estsys1, appears in theLinear Analysis Workspaceand the its frequency response is added toBode Plot 1.

The frequency response for the estimated model matches that of the linearized model. You can use this approach to validate an exact linearization.

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