This example shows how to use response plots to analyze batch linearization results in Linear Analysis Tool. The term batch linearization results refers to linearizations for varying parameter values, such as illustrated in Batch Linearize Model for Parameter Value Variations Using Linear Analysis Tool. You can use the techniques illustrated in this example to analyze the frequency response, stability, and other system characteristics for batch linearization results.
For this example, suppose that you have batch linearized a model as described in
Batch Linearize Model for Parameter Value Variations Using Linear Analysis Tool. You have generated a step response plot of an array of linear models computed for
a 2-D parameter grid, with variations of outer-loop controller gains
When you perform batch linearization, Linear Analysis Tool generates a plot showing the responses of all linear models resulting from the linearization. You choose the response plot type, such as Step, Bode, or Nyquist, when you linearize. You can create additional plots at any time as described in Analyze Results Using Linear Analysis Tool Response Plots.
To view the parameters associated with a particular response, click the response on the plot.
A data tip appears on the plot, providing information about the selected response
and the related model. The last lines of the data tip show the parameter combination
that yielded this response. For example, in this plot, the selected response
corresponds to the model obtained by setting
Suppose you want to view the responses for only the models linearized at a
Ki1 value, the middle value
0.0410. Right-click the plot and select Array
Selector. The Model Selector for LTI Arrays dialog box opens.
The Selection Criterion Setup panel contains two columns, one
for each model array dimension of
linsys1. Linear Analysis Tool
flattens the 2-D parameter grid into a one-dimensional array, so that variations in
Ki1 are represented along the
indices shown in column 1. To determine which entries in this
array correspond to
Ki1 = 0.0410, examine the Parameter
Ki1 = 0.0410 values are the seventh to twelfth entries in
this table. Therefore, you want to select array indices 7–12.
In the Model Selector for LTI Arrays dialog box, enter
in the field below column 1. The selection in the column changes
to reflect this subset of the array.
Click OK. The step plot displays responses only for the
Ki1 = 0.0410.
You can export the model array to the MATLAB® workspace to perform further analysis or control design. To do so, in the Linear Analysis Tool, in the Data Browser, drag the array from Linear Analysis Workspace to the MATLAB workspace.
You can then use Control System
Toolbox™ control design tools, such as the Linear
System Analyzer (Control System Toolbox) app, to analyze linearization results. Or, use Control System
Toolbox control design tools, such as
pidtune or Control System Designer, to design controllers for the linearized