showConfidence

Display confidence regions on response plots for identified models

Syntax

showConfidence(plot_handle) showConfidence(plot_handle,sd)

Description

showConfidence(plot_handle)displays the confidence region on the response plot, with handleplot_handle, for an identified model.

showConfidence(plot_handle,sd)displays the confidence region forsdstandard deviations.

Input Arguments

plot_handle

Response plot handle.

plot_handleis the handle for the response plot of an identified model on which the confidence region is displayed. It is obtained as an output of one of the following plot commands:bodeplot,stepplot,impulseplot,nyquistplot, oriopzplot.

sd

Standard deviation of the confidence region. A common choice is 3 standard deviations, which gives 99.7% significance.

Default:getoptions(plot_handle,'ConfidenceRegionNumberSD')

Examples

collapse all

View Confidence Region for Identified Model

Open Live Script

Show the confidence bounds on the bode plot of an identified ARX model.

Obtain identified model and plot its bode response.

loadiddata1z1sys = arx(z1, [2 2 1]); h = bodeplot(sys);

Figure contains 2 axes. Axes 1 with title From: u1 To: y1 contains an object of type line. This object represents sys. Axes 2 contains an object of type line. This object represents sys.

z1is aniddataobject that contains time domain system response data.sysis anidpolymodel containing the identified polynomial model.his the plot handle for the bode response plot ofsys.

Show the confidence bounds forsys.

showConfidence(h);

Figure contains 2 axes. Axes 1 with title From: u1 To: y1 contains an object of type line. This object represents sys. Axes 2 contains an object of type line. This object represents sys.

This plot depicts the confidence region for 1 standard deviation.

Specify the Standard Deviation of the Confidence Region

Open Live Script

Show the confidence bounds on the bode plot of an identified ARX model.

Obtain identified model and plot its bode response.

loadiddata1z1sys = arx(z1, [2 2 1]); h = bodeplot(sys);

Figure contains 2 axes. Axes 1 with title From: u1 To: y1 contains an object of type line. This object represents sys. Axes 2 contains an object of type line. This object represents sys.

z1is aniddataobject that contains time domain system response data.sysis anidpolymodel containing the identified polynomial model.his the plot handle for the bode response plot ofsys.

Show the confidence bounds forsysusing 2 standard deviations.

sd = 2; showConfidence(h,sd);

Figure contains 2 axes. Axes 1 with title From: u1 To: y1 contains an object of type line. This object represents sys. Axes 2 contains an object of type line. This object represents sys.

sdspecifies the number of standard deviations for the confidence region displayed on the plot.

Alternatives

You can interactively turn on the confidence region display on a response plot. Right-click the response plot, and selectCharacteristics>Confidence Region.