idnlhw/plot

(Not recommended) Plot input and output nonlinearity, and linear responses of Hammerstein-Wiener model

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idnlhw/plot is not recommended. Use nlhwPlot instead to plot nonlinear ARX model nonlinearities. For more information, see Version History.

Syntax

plot(model)
plot(model,LineSpec)
plot(model1,...,modelN)
plot(model1,LineSpec1...,modelN,LineSpecN)
plot(___,Name,Value)

Description

plot(model) plots the input and output nonlinearity, and linear responses of a Hammerstein-Wiener model on a Hammerstein-Wiener plot. The plot shows the responses of the input and output nonlinearity, and linear blocks that represent the model.

example

plot(model,LineSpec) specifies the line style.

plot(model1,...,modelN) generates the plot for multiple models.

plot(model1,LineSpec1...,modelN,LineSpecN) specifies the line style for each model. You do not need to specify the line style for all models.

example

plot(___,Name,Value) specifies plot properties using additional options specified by one or more Name,Value pair arguments. This syntax can include any of the input argument combinations in the previous syntaxes.

example

Examples

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Estimate a Hammerstein-Wiener Model and plot responses of its input and output nonlinearity and linear blocks.

load iddata3
model1 = nlhw(z3,[4 2 1],'idSigmoidNetwork','idDeadZone');
plot(model1)

Explore the various plots in the plot window by clicking one of the three blocks that represent the model:

  • uNL - Input nonlinearity, representing the static nonlinearity at the input ( model.InputNonlinearity ) to the LinearBlock.

  • Linear Block - Step, impulse,Bode and pole-zero plots of the embedded linear model ( model.LinearModel ). By default, a step plot is displayed.

  • yNL - Output nonlinearity, representing the static nonlinearity at the output ( model.OutputNonlinearity ) of the Linear Block.

Load data, estimate two idnlhw models, and plot them using line style specifications..

load iddata3
model1 = nlhw(z3,[4 2 1],'idSigmoidNetwork','idDeadZone');
model2 = nlhw(z3, [4 2 1],[],'idSigmoidNetwork');
plot(model1,'b-',model2,'g')

Load data, estimate two idnlhw models, and plot them with additional specifications.

load iddata3
model1 = nlhw(z3,[4 2 1],idSigmoidNetwork,idDeadZone);
model2 = nlhw(z3, [4 2 1],[],idSigmoidNetwork);
plot(model1,model2,'time',1:500,'freq',{0.01,100},...
'OutputRange',[0 1000]);

Load data, estimate two idnlhw models, and plot them with additional specifications.

load iddata3
model1 = nlhw(z3,[4 2 1],idSigmoidNetwork,idDeadZone);
model2 = nlhw(z3, [4 2 1],[],idSigmoidNetwork);
plot(model1,model2,'time',1:500,'freq',{0.01,100},...
'OutputRange',[0 1000]);

Input Arguments

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Estimated Hammerstein-Wiener model, specified as an idnlhw model object. Use nlhw to estimate the model.

Line style, marker symbol, and color, specified as a character vector. LineSpec takes values such as 'b', 'b+:'. For more information, see the plot reference page in the MATLAB® documentation.

Data Types: char

Name-Value Arguments

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Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: plot(model,'NumberofSamples',10) specifies to use 10 data points for the input regressors.

Number of data points to use for the input regressors when evaluating the nonlinearities at individual input or output channels, specified as a positive integer. This property does not affect the plots of the linear block.

Data Types: double

Minimum and maximum regressor values to use when evaluating the nonlinearities at each input channel, specified as positive integers or [min max] vector, where minimum value is less than the maximum value.

You can use 'uRange' as a shortcut name for this property.

Data Types: double

Minimum and maximum regressor values to use when evaluating the nonlinearities at each output channel, specified as positive integers or [min max] vector, where minimum value is less than the maximum value.

You can use 'yRange' as a shortcut name for this property.

Data Types: double

The time samples at which the transient responses (step and impulse) of the linear block of the idnlhw model must be computed, specified as one of the following values:

  • Positive scalar — Denotes end time for transient responses of all models. For example, 10.

  • Vector of time instants — A double vector of equi-sampled values denotes the time samples at which the transient response must be computed. For example, [0:0.1:10].

This property takes the same values as the step command on the model.

Frequencies at which to compute the Bode response, specified as one of the following values:

  • [Wmin Wmax] range — Frequency interval between Wmin and Wmax (in units rad/(model.TimeUnit)) covered using logarithmically placed points.

  • Vector of non-negative frequency values — Allows computation of bode response at those frequencies.

By default, the response is computed at some automatically chosen frequencies inside the Nyquist frequency range. Frequencies above Nyquist frequency (pi/model.Ts) are ignored.

This property takes the same values as the bode command on the model.

More About

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Version History

Introduced in R2014a

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See Also

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