User`s guide

2 Choosing Your System Identification Strategy
Summary of Model Constructors (Continued)
Model Constructo r Resulting Model Class SingleorMultipleOutputs?
idgrey
Linear ordinary differential or
difference equations (grey-box
models). You write an M-file
that translates user parameters
to state-space matrices.
Single- and multiple-output
models.
idnlgrey
Nonlinear ordinary differential
or difference equation (grey -box
models). You write an M-file
or MEX-file to represent the
set of first-order differential or
difference equations.
Supports single- and
multiple-output models.
idnlarx
Nonlinear ARX models, which
define the predicted output as a
nonlinear function of past inputs
and outputs.
Single- or m ultiple-output
models.
idnlhw
Nonlinear Hammerstein-Wiener
models, which include a linear
dynamic system with nonlinear
static transformations of inputs
and outputs.
Single- or m ultiple-output
models. Does not support time
series.
For more information about when to use these commands, see “When to
Construct a M odel Structure Independently of Estimation” on page 2-12.
Model Proper ties
• “Categories of Mo de l Properties” on page 2-15
• “Specifying Model Pro perties for Estimation” on page 2-16
• “Viewing M odel Properties and Estimated Parameters” on page 2-17
• “Getting Help on Mo de l Properties at the Command Line” on page 2-19
2-14