Estimate Transfer Function Models at the Command Line

General workflow for estimating transfer function models at the command line.

Before you estimate a transfer function model, you must have:

• Input/Output data. See Representing Time- and Frequency-Domain Data Using iddata Objects. For supported data formats, see Data Supported by Transfer Function Models.

• Performed any required data preprocessing operations. You can detrend your data before estimation. For more information, see Ways to Prepare Data for System Identification.

  Alternatively, you can specify the input/output offset for the data using an estimation option set. Use tfestOptions to create the estimation option set. Use the InputOffset and OutputOffset name and value pairs to specify the input/output offset.

Estimate continuous-time and discrete-time transfer function models using tfest. The output of tfest is an idtf object, which represents the identified transfer function.

The general workflow in estimating a transfer function model is:

1. Create a data object (iddata or idfrd) that captures the experimental data.

2. (Optional) Specify estimation options using tfestOptions.

3. (Optional) Create a transfer function model that specifies the expected model structure and any constraints on the estimation parameters.

4. Use tfest to identify the transfer function model, based on the data.

5. Validate the model. See Model Validation.