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Specify Portion of Model to Linearize in Linear Analysis Tool

To specify the portion of the model to linearize, you can define linear analysis points using the Linear Analysis Tool. Analysis points represent linearization inputs, outputs, and loop openings for your model. Using this method you can specify multiple sets of analysis points without changing your model.

Alternatively, you can define analysis points:

Specify Analysis Points

In the Linear Analysis Tool, you specify analysis points using linearization I/O sets. You can specify one or more linearization I/O sets, without introducing changes to the model.

To create a linearization I/O set:

  1. On the Linear Analysis tab, in the Analysis I/Os drop-down list, select Create New Linearization I/Os.

  1. In your Simulink model, select one or more signals that you want to define as analysis points.

    The selected signals appear in the Create linearization I/O set dialog box under Currently selected signals.

  2. Under Currently selected signals, click the signal you want to add. To select multiple signals, hold Ctrl and click each signal you want to add.

    To add a signal from within a bus signal, expand the bus and select the signal. For example, select the data signal within the COUNTERBUS signal.

  3. To add the signal to list of Analysis I/Os, click Add.

  4. In the Configuration drop-down list for the signal, select the type of analysis point you want to define:

    • Input Perturbation — Specifies an additive input to a signal.

    • Output Measurement — Takes a measurement at a signal.

    • Loop Break — Specifies a loop opening.

    • Open-Loop Input — Specifies a loop break followed by an input perturbation.

    • Open-Loop Output — Specifies an output measurement followed by a loop break.

    • Loop Transfer — Specifies an output measurement before a loop break followed by an input perturbation.

    • Sensitivity — Specifies an input perturbation followed by an output measurement.

    • Complementary Sensitivity — Specifies an output measurement followed by an input perturbation.

    For more information on the different types of analysis points, see Specify Portion of Model to Linearize.

  5. Repeat steps 1–4 for any other signals you want to define as analysis points.

    Tip

    To highlight the source block of an analysis point in the Simulink model, in the Analysis I/Os list, select the analysis point, and click Highlight.

  6. In the Variable name box, enter a name for the I/O set.

  7. Click OK.

The software adds the linearization I/O set to the Linear Analysis Workspace.

The software also adds the linearization I/O set to the Analysis I/Os drop-down list and automatically selects it.

Edit Analysis Points

You can interactively edit a linearization I/O set stored in the Linear Analysis Tool using the Edit dialog box. To open the Edit dialog box, in the Linear Analysis Workspace, double-click the I/O set you want to edit.

Alternatively, you can open the Edit dialog box for the current selected linearization I/O set in the Analysis I/Os drop-down list. To do so, in the drop-down list, under View/Edit, click Edit.

In the Edit dialog box, you can add or remove analysis points, change the type for existing analysis points, or enable or disable analysis points. Once you have finished editing the I/O set, save your changes by closing the dialog box.

Tip

To highlight the location in the Simulink model of any signal in the current list of analysis I/O points, select the I/O point in the list, and click Highlight.

Add Analysis Point to I/O Set

To add an analysis point to the linearization I/O set:

  1. In your Simulink model, select one or more signals that you want to add to the linearization I/O set.

    The selected signals appear in the Edit dialog box under Currently selected signals.

  2. Under Currently selected signals, click the signal you want to add. To select multiple signals, hold Ctrl, and click each signal you want to add.

  3. To add the signal to list of Analysis I/Os, click Add.

  4. In the Configuration drop-down list for the signal, select the type of analysis point you want to define. For example, if you want the signal to be an open-loop linearization output point, select Open-loop Output.

Remove Analysis Point from I/O Set

To remove an analysis point from the linearization I/O set, in the Analysis I/Os section, click the signal you want to remove, and click Delete.

Change Analysis Point Type

To change the linear analysis point type for a signal, in the Analysis I/Os section, in the Configuration drop-down list for the signal, select the analysis point type. For example, if you want the signal to be a linearization output point, select Output Measurement.

Enable or Disable Analysis Points

To modify an existing linearization I/O set without removing analysis points, you can disable one or more analysis points. To do so, in the Analysis I/Os section, under Active, clear the corresponding check box.

When you linearize your model using the linearization I/O set, the software ignores any disabled analysis points.

To enable a disabled analysis point, select the corresponding check box.

Edit Simulink Model Analysis Points

You can modify analysis points stored in your Simulink model using the Linear Analysis Tool. To do so, on the Linear Analysis tab, in the Analysis I/Os drop-down list, select Model I/Os, and then, in same drop-down list, select Edit Model I/Os.

In the Edit model I/Os dialog box, you can:

  • Change the type for an analysis point using the corresponding Configuration drop-down list.

  • Delete an analysis point from the model. To do so, click the signal you want to remove, and click Delete.

  • Enable or disable an analysis point using the corresponding Active check box. When you disable an analysis point, in the Simulink model, the software removes the annotation from the corresponding signal.

    Note

    If you close the Linear Analysis Tool, any analysis points that you disabled in this manner are deleted from the Simulink model. To keep the analysis points in the model, reenable them before closing the Linear Analysis Tool.

For information on adding analysis points to the model, see Specify Portion of Model to Linearize in Simulink Model.

See Also

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