Model Linearizer

Linearize Simulink models

Description

Model Linearizer lets you perform linear analysis of nonlinear Simulink^® models.

Using this app, you can:

• Interactively linearize models at different operating points

• Interactively obtain operating points by trimming or simulating models

• Perform exact linearization of nonlinear models

• Perform frequency response estimation of nonlinear models

• Batch linearize models for varying parameter values

• Generate MATLAB^® code for performing linearization tasks

• Generate MATLAB code for computing operating points

More

Limitations

• Linearization is not supported for model hierarchies that contain referenced models configured to use a local solver.

• Linearization is not supported for Simscape™ networks configured to use a local solver.

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Open the Model Linearizer App

• Simulink Toolstrip: On the Apps tab, under Control Systems, click Model Linearizer.

• Simulink Toolstrip: On the Apps tab, under Control Systems, click Frequency Response Estimator.

• Simulink Toolstrip: On the Linearization tab, click Model Linearizer.

• Simulink Toolstrip: On the Linearization tab, click Frequency Response Estimator.

• Simulink Toolstrip: On the Linearization tab, click Linearize Block.

Examples

• Linearize Simulink Model at Model Operating Point
• Linearize at Trimmed Operating Point
• Linearize at Simulation Snapshot
• Estimate Frequency Response Using Model Linearizer
• Specify Portion of Model to Linearize in Model Linearizer
• Analyze Results Using Model Linearizer Response Plots
• Batch Linearize Model for Parameter Value Variations Using Model Linearizer

Parameters

Linear Analysis Tab

Analysis I/Os — Linearization inputs, outputs, and loop openings

Model I/Os (default) | linearization I/O set

Linearization inputs, outputs, and loop openings. The currently active I/O set is displayed. To change the I/O set, select one of the following:

• Model I/Os — Use the inputs, outputs, and loop openings specified in the Simulink model. For more information on specifying analysis points in your model, see Specify Portion of Model to Linearize in Simulink Model.

• Root Level Inports and Outports — Use the root level inputs and outputs of the Simulink model.

• Linearize the Currently Selected Block — Use the input and output ports of the currently selected block in the Simulink model.

• Create New Linearization I/Os — Specify inputs, outputs, and loop openings. For more information, see Specify Portion of Model to Linearize in Model Linearizer.

• Existing I/Os — Select a previously created I/O set.

• View/Edit — View or edit the currently selected operating point. For more information, see Edit Analysis Points.

Operating Point — Linearization operating point

Model Initial Condition (default) | operating point

Linearization operating point. The current operating point is displayed. To change the operating point, select one of the following:

• Model Initial Condition — Use the initial conditions defined in the Simulink.

• Linearize At — Simulate the model using the model initial conditions, and use the simulation snapshot at the specified time as the operating point. For more information, see Linearize at Simulation Snapshot.

• Linearize at Multiple Points — Select multiple previously created operating points.

• Existing Operating points — Select a previously created operating point.

• Trim Model — Compute a steady-state operating point. For more information, see Compute Steady-State Operating Points.

• Take Simulation Snapshot — Simulate the model using the model initial conditions, and compute an operating point at the specified simulation snapshot times. For more information, see Find Operating Points at Simulation Snapshots.

• View/Edit — View or edit the currently selected operating point.

Parameter Variations — Parameters to vary for batch linearization

None (default) | parameters to vary

To vary parameters for batch linearization, in the drop-down list, click Select parameters to vary. On the Parameter Variations tab, specify the parameters to vary.

For more information, see Specify Parameter Samples for Batch Linearization.

Result Viewer — Open linearization result viewer

off (default) | on

Select to display result details after linearization. For more information, see View Linearized Model Equations Using Model Linearizer.

Linearization Advisor — Collect diagnostic information and open Linearization Advisor

off (default) | on

Select to collect diagnostic information during linearization and open an Advisor tab for interactive troubleshooting of linearization problems. For more information, see Troubleshoot Linearization Results in Model Linearizer.

Note

Model Linearizer only collects diagnostic information when Linearization Advisor is selected before performing a linearization task.

Estimation Tab

Input Signal — Estimation input signal

Sinestream | Fixed Sample Time Sinestream | Chirp | Random | PRBS Pseudorandom Binary Sequence

Estimation input signal. The current input signal is displayed. To change the input signal, select one of the following:

• Sinestream — Create an input signal that consists of adjacent sine waves of varying frequencies. For more information, see Sinestream Input Signals.

• Fixed Sample Time Sinestream — Create a discrete-time sinestream input with a specified sample time.

• Chirp — Create a swept-frequency cosine input signal. For more information, see Chirp Input Signals.

• Random — Create a random input signal.

• PRBS Pseudorandom Binary Sequence — Create a pseudorandom binary sequence (PRBS) input signal. For more information, see PRBS Input Signals.

Analysis I/Os — Linearization inputs, outputs, and loop openings

Model I/Os (default) | linearization I/O set

Linearization inputs, outputs, and loop openings. The currently active I/O set is displayed. To change the I/O set, select one of the following:

• Model I/Os — Use the inputs, outputs, and loop openings specified in the Simulink model. For more information on specifying analysis points in your model, see Specify Portion of Model to Linearize in Simulink Model.

• Root Level Inports and Outports — Use the root level inputs and outputs of the Simulink model.

• Linearize the Currently Selected Block — Use the input and output ports of the currently selected block in the Simulink model.

• Create New Linearization I/Os — Specify inputs, outputs, and loop openings. For more information, see Specify Portion of Model to Linearize in Model Linearizer.

• Existing I/Os — Select a previously created I/O set.

• View/Edit — View or edit the currently selected operating point. For more information, see Edit Analysis Points.

Operating Point — Linearization operating point

Model Initial Condition (default) | operating point

Linearization operating point. The current operating point is displayed. To change the operating point, select one of the following:

• Model Initial Condition — Use the initial conditions defined in the Simulink.

• Linearize At — Simulate the model using the model initial conditions, and use the simulation snapshot at the specified time as the operating point. For more information, see Linearize at Simulation Snapshot.

• Linearize at Multiple Points — Select multiple previously created operating points.

• Existing Operating points — Select a previously created operating point.

• Trim Model — Compute a steady-state operating point. For more information, see Compute Steady-State Operating Points.

• Take Simulation Snapshot — Simulate the model using the model initial conditions, and compute an operating point at the specified simulation snapshot times. For more information, see Find Operating Points at Simulation Snapshots.

• View/Edit — View or edit the currently selected operating point.

Result Viewer — Open estimation result viewer

off (default) | on

Select to display result details about the estimation configuration and input signal used for estimation.

Diagnostic Viewer — Collect diagnostic information and open diagnostic viewer

off (default) | on

Select to collect diagnostic information that displays after estimation. You can use the diagnostic information to analyze the estimation result and troubleshoot estimation problems. For more information, see Analyze Estimated Frequency Response.

Note

Model Linearizer only collects diagnostic information when Diagnostic Viewer is selected before performing an estimation task.

Version History

Introduced in R2011b

R2023b: Simulink Online support

Starting in R2023b, Model Linearizer is supported in Simulink Online™.

R2021b: Linearize Simulink model to sparse state-space model

Using Model Linearizer, you can obtain a sparse linear model from a Simulink model that contains a Sparse Second Order or Descriptor State-Space block. For more information, see Linearize Sparse Models.

R2021a: Automatically determine PRBS estimation input signal parameters

When creating PRBS input signals for estimating frequency responses in Model Linearizer, you can now automatically determine the signal parameters Number of periods and Signal order based on a frequency range.

R2021a: Result thinning for frequency response estimation

When you have an estimated frequency response result with a large number of frequency points, you can use result thinning in Model Linearizer to extract interpolated frequency response data from an estimated frequency response model across a specified frequency range and number of frequency points. For more information, see Analyze Estimated Frequency Response.

R2020a: Linear Analysis Tool is now Model Linearizer

The Linear Analysis Tool is now the Model Linearizer app. The features of the app remain the same, only the name has changed.

R2020a: PRBS input signals for frequency response estimation

You can now estimate the frequency response of your Simulink model using pseudorandom binary sequence (PRBS) input signals. For more information, see PRBS Input Signals.