User`s guide

Using Model Output Plots to Validate and Compare Mod els
• For frequency-response data, the plot shows the simulated amplitude of the
model frequency response.
For linear models, you can estimate a model using time-domain data, and
then validate the model using f requen cy domain data. For nonlinear models,
you can only use time-domain data for both estimation and validation.
The following figure shows a sample Model Output plot, created in the System
Identification Tool GUI.
Choosing Simulated or Predicted Output
How you validate the model output should match h ow you plan to use the
model. If you plan to use the m odel for simulation applications, validate the
model b y comparing simulated output to the validation data. Using a m odel
forpredictioniscommonincontrolsapplications where you want to predict
output for a specific number of steps in advance. For example, if you are
modeling a plant for a control system, your model must perform for prediction
over a horizon that corresponds to the time-constant of the system.
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