User`s guide

Creating Model Structures at the Command Line
Creating Model Structures at the Command Line
In this section...
“About System Identification Toolbox Model Objects” on page 2-11
“When to Construct a Model Structure Independently of Estimation” on
page 2-12
“Commands for Constructing Model Structures” on page 2-13
“Model Pro per ties” on pag e 2-14
“See Also” on page 2-20
About System Identification Toolbox Model Objects
Objects are based on model classes. Each class is a blueprint that defines the
following information about your model:
• How the object stores data
• Which operations you can perform on the object
This too lbox includes nine classes for representing models. For example,
idpoly represents linear input-output polynomial models, and idss
represents linear state-space models. For a complete list of available m odel
objects, see “Commands for Constructing Model Structures” on page 2-13.
Model properties define how a model object stores information. Model objects
store information about a model, including the mathematical form of a
model, names of input and output channels, units, names and values of
estimated parameters, parameter uncertainties, algorithm specifications, and
estimation information. For example, the
idpoly model class has a property
called
InputName for storing one or more input channel names. Different
model objects have different prope rties.
The allowed operations on an object are called methods.IntheSystem
IdentificationToolboxproduct,somemethodshavethesamenamebutapply
to multiple mode l objects. For example, the method
bode creates a bode plot
for all linear model objects. However, other methods are unique to a specific
2-11