Simulink Control Design™ - MathWorks

Linearize Multirate Models

You can linearize a Simulink model that contains blocks with different sample times using

Simulink Control Design software. By default, the linearization tools:

• Convert sample times using a zero-order hold conversion method.


• Create a linearized model with a sample time equal to the largest sample time of the
  blocks on the linearization path.

You can change either of these behaviors by specifying linearization options, which affects

the linearization result.

For more information on how Simulink Control Design software linearizes multirate

models, see “Linearization of Multirate Models” on page 2-183.

Change Sample Time of Linear Model

By default, the software chooses the largest sample time of the multirate model. If the

default sample time is not appropriate for your application, you can specify a different

sample time.

To specify the sample time of the linear model in the Linear Analysis Tool:

1

On the Linear Analysis tab, click More Options.

2 In the Options for exact linearization dialog box, on the Linearization tab, in the

Enter sample time (sec) field, specify the sample time. You can specify any of the

following values:

• -1 — Use the largest sample time from the model.


• 0 — Create a continuous-time model. In this case, the software creates a discrete-
  time model using the largest sample time from the model, then converts the
  resulting model to continuous time.


• Positive scalar — Use the specified value for the sample time.

To specify the sample time of the linear model at the command line, create a

linearizeOptions option set, and set the SampleTime option. For example:

opt = linearizeOptions;

opt.SampleTime = 0.01;

2 Linearization