Contents

Plots in the Design Optimization Tool

Adding Plots in Design Optimization Tool

To create a new plot or to add to an existing plot in the Design Optimization Tool, choose the variable to plot in the Data to Plot list. Then select the plot type using the Add Plot list. The Add Plot list has entries for the supported plot types for the given plot variable.

Plotting Current Response

To display the current response, click Plot Current Response in the Response Optimization tab or the Figure tab of the Design Optimization tool. The current response appears as a thick line.

Plotting Intermediate Steps

To turn on, or off, the display of the response signal at intermediate steps during the optimization, right-click within the white space in the plot and select Responses > Show Iteration Responses. The response at an intermediate step is based on parameter values at that intermediate point in the optimization.

Modifying Plot Properties

Modifying Properties of Response Plots

Right-click the white space in a plot and select Axes Properties to open the Property Editor dialog box.

This figure shows the Property Editor dialog box for a step response.

In general, you can change the following properties of response plots.

  • Labels — Titles and X- and Y-labels

    To specify new text for plot titles and axis labels, type the new string in the field next to the label you want to change. The label changes immediately as you type, so you can see how the new text looks as you are typing.

  • Limits — Numerical ranges of the x- and y- axes

    Default values for the axes limits make sure that the maximum and minimum x and y values are displayed. If you want to override the default settings, change the values in the Limits pane fields. The Auto-Scale check box automatically clears if you click a different field. The new limits appear immediately in the response plot.

    To reestablish the default values, select the Auto-Scale check box again.

  • Units — Units where applicable (e.g., rad/s to Hertz). If you cannot customize units, the Property Editor displays that no units are available for the selected plot.

  • Style — Show a grid, adjust font properties, such as font size, bold and italics, and change the axes foreground color

  • Options — Change options where applicable. These include peak response, settling time, phase and gain margins, etc. Plot options change with each plot response type. The Property Editor displays only the options that make sense for the selected response plot. For example, phase and gain margins are not available for step responses.

Plot Types

Response Plots

You can view model signals and the requirements applied to the signal using a response plot. You can also plot the frequency response of a system (requires Simulink® Control Design™).

The response plot shows the system response as it varies during optimization. You can also view the uncertain system responses in the plot.

    Tip   To select the responses and systems displayed in a given plot, right-click on the plot and use the Systems and Responses menu.

Spider Plots

You can compare the values of design variable sets or evaluated requirements using a spider plot.

Spider plots depict multivariate data using an axis for each variable. The various axes are arranged clockwise and have a common intersecting point, as this example shows:

    Tip   To view only some of the requirement values in a given plot, right-click on the plot and select the requirements in the Show list.

For information on using a spider plot to compare design variables sets or evaluated requirements, see Compare Requirements and Design Variables Using Spider Plot

Iteration Plots

You can plot the values of design variables and requirements as they vary during optimization using an iteration plot.

Iteration plots depict the value of the plot variable(s) for each iteration. The x-axis represents the iteration number, as this example shows:

You can export the values of a plotted variable for a given iteration. For more information, see Export Design Variables and Requirement Values for an Iteration.

    Tip   To view scaled values of the plotted variable(s), right-click on the plot and select Show scaled values.

Export Design Variables and Requirement Values for an Iteration

To export the values of design variables or requirements:

  1. Open the Export Iteration Data dialog box.

    Right-click on the iteration plot and select Export.

  2. Specify the plotted variable that you want to export using the Data to export list.

  3. Specify the iteration for which you want to export data in the Iteration(s) to export box.

    To specify multiple iterations, use a vector of integers. For example, [0 2 5].

  4. Specify the variable name for the exported data using the Export to a variable named box.

  5. Export the data to the Design Optimization Workspace.

    Click OK. The exported data variable appears in the Design Optimization Workspace.

      Note:   The iteration number is added as a suffix to the exported data variable name.

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