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Estimate State-Space Models in System Identification Tool

Prerequisites

1. Select Estimate > State Space Models.

The State Space Models dialog box opens.

Tip For more information on the options in the dialog box, click Help.

2. Specify a model name by clicking adjacent to Model name. The name of the model must be unique

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in the Model Board.

3. Select the Specify value option (if not already selected) and specify the model order in the edit field.

Model order refers to the number of states in the state-space model.

Tip When you do not know the model order, search and select for an order. For more information,

see Estimate Model With Selected Order in the GUI.

4. Select the Continuous-time or Discrete-time option to specify whether to estimate a continuous- or

discrete-time model.

You cannot estimate a discrete-time model if the working data is continuous-time frequency-domain

data.

5. Expand the Model Structure Selection section to configure the model structure, such as canonical

form, whether to estimate the disturbance component (K matrix), and specification of feedthrough and

input delays.

For more information about the type of state-space parameterization, see Supported State-Space

Parameterizations.

6. Expand the Estimation Options section to select the estimation method, and configure the cost

function.

Select one of the following Estimation Method from the drop-down list and configure the options. For

more information about these methods, see State-Space Model Estimation Methods.

Subspace (N4SID)

Prediction Error Minimization (PEM)

Regularized Reduction

7. Click Estimate to estimate the model. A new model gets added to the System Identification Tool.

Next Steps

Validate the model by selecting the appropriate response type in the Model Views area of the tool. For

more information about validating models, see Validating Models After Estimation.

Export the model to the MATLAB® workspace for further analysis by dragging it to the To Workspace

rectangle in the tool.

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