System Identification Toolbox™

saturation

Class representing saturation nonlinearity estimator for Hammerstein-Wiener models

Syntax

s=saturation(LinearInterval,L)

saturation is an object that stores the saturation nonlinearity estimator for estimating Hammerstein-Wiener models.

You can use the constructor to create the nonlinearity object, as follows:

s=saturation(LinearInterval,L) creates a saturation nonlinearity estimator object, initialized with the linear interval L.

Use evaluate(s,x) to compute the value of the function defined by the saturation object s at x.

Use saturation to define a nonlinear function , where F is a function of x and has the following characteristics:

y and x are scalars.

You can specify the property value as an argument in the constructor to specify the object.

After creating the object, you can use get or dot notation to access the object property values. For example:

% List LinearInterval property value
get(s)
s.LinearInterval

You can also use the set function to set the value of particular properties. For example:

set(s, 'LinearInterval', [-1.5 1.5])

The first argument to set must be the name of a MATLAB^® variable.

Property Name Description

Property Name	Description
`LinearInterval`	1-by-2 row vector that specifies the initial interval of the saturation Default=`[NaN NaN]`. For example: saturation('LinearInterval',[-1.5 1.5])

LinearInterval

1-by-2 row vector that specifies the initial interval of the saturation
Default=[NaN NaN].

For example:

saturation('LinearInterval',[-1.5 1.5])

Use saturation to specify the saturation nonlinearity estimator in Hammerstein-Wiener models. For example:

m=nlhw(Data,Orders,saturation([-1 1]),[]);

The saturation nonlinearity is initialized at the interval [-1 1]. The interval values are adjusted to the estimation data by nlhw.