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Compute Uncertain State-Space Models from金宝appModels

When you have the金宝app®Control Design™software, you can compute anuncertain linearization, i.e., an uncertain state-space model (uss) combining the uncertain variables with linearized dynamics. Use theussmodel to perform linear analysis and robust control design.

You can compute an uncertain linearization in one of the following ways:

Obtain Uncertain State-Space Model from金宝appModel

To obtain an uncertain state-space model from a model that containsUncertain State Spaceblocks, use the following steps:

Note

If you do not haveUncertain State Spaceblocks in the model but still want to obtain an uncertain state-space model, seeSpecify Uncertain Linearization for Core or Custom Simulink Blocks.

  1. (Prerequisite) Create or open the Simulink model.

  2. (Prerequisite) In the Simulink model, specify the linearization input and output points usingSimulink Control Designgetlinioorlinio命令s. For more information, seeSpecify Portion of Model to Linearize(Simulink Control Design).

  3. (Prerequisite) If you have not already done so, specify uncertainty in the Simulink model as described inSpecify Uncertainty Using Uncertain State Space Blocks.

    Note

    The software does not evaluate the uncertain variables during linearization. Thus, the value of the uncertainty does not affect the linearization.

  4. Runulinearize计算不确定的线性化。这command returns anussmodel.

    Note

    If you use theSimulink Control Designlinearize(Simulink Control Design)命令, theUncertain State Spaceblocks linearize to their nominal value.

For more information on linearization and how to evaluate the results, seeLinearization Basics(Simulink Control Design).

For an example of how to use theSimulink Control Designlinearize(Simulink Control Design)命令, seeLinearization of Simulink Models with Uncertainty.

Specify Uncertain Linearization for Core or Custom金宝appBlocks

In some cases, you cannot useUncertain State Spaceblocks in the Simulink model because you share the model or generate code. You can still account for uncertainty in your linear analysis without specifying uncertainty usingUncertain State Spaceblocks. Robust Control Toolbox™ lets you specify a core or custom Simulink block to linearize to an uncertain variable. The linearization produces an uncertain state-spaceussmodel. The specified uncertainty associates only with the block and does not affect the model simulation. For more information, seeSpecify Linear System for Block Linearization Using MATLAB Expression(Simulink Control Design).

Note

If you haveUncertain State Spaceblocks in the model and want to obtain an uncertain state-space model, seeObtain Uncertain State-Space Model from Simulink Model.

To specify blocks to linearize to uncertain variables and obtain an uncertain state-space model:

  1. (Prerequisites) Create or open the Simulink model. Specify linearization input and output points using theSimulink Control Designgetlinioorlinio命令s.

    For this example, you can open the modelrct_ulinearize_builtin.

  2. Specify a block to linearize to an uncertain variable:

    1. Right-click the block and selectLinear Analysis > Specify Selected Block Linearization.

      Simulink model canvas with right-click menu displayed on a block

      This action opens the Block Linearization Specification dialog box.

      Block Linearization Specification dialog box showing the block linearization specified as a MATLAB expression, plant * (1 + wt * input_unc)

    2. In the Block Linearization Specification dialog box, select theSpecify block linearization using one of the following:check box. Selecting this check box lets you to specify an uncertain variable for linearization.

      This check box defaults toMATLAB Expressionin the drop-down menu. This option lets you specify the block to linearize to an uncertain variable using a MATLAB®expression containing Robust Control Toolbox functions. To learn more about the options, seeSpecify Linear System for Block Linearization Using MATLAB Expression(Simulink Control Design).

    3. In theEnter an expression to specify the linearization of the Simulink blockfield, enter an expression, which must evaluate to an uncertain variable or uncertain model, such asureal,umat,ultidyn,umargin, oruss.

      Block Linearization Specification dialog box showing the block linearization specified as the MATLAB expression ss(ureal('a',-5),5,1,1)

    4. ClickOKto save the changes.

      Note

      You can also specify a block to linearize to an uncertain variable at the command line. For an example, seeLinearize Simulink Block to Uncertain Model.

  3. Run thelinearize命令计算不确定的线性化。这command returns anussmodel.

For more information on linearization and how to validate linearization results, seeLinearization Basics(Simulink Control Design).

For an example of how to use thelinearize命令to compute an uncertain linearization, seeLinearization of Simulink Models with Uncertainty.

Using Uncertain Linearization for Analysis or Control Design

After computing an uncertain linearization, you can perform any analysis or design tasks you would perform on any linear model, including:

See Also

|(Simulink Control Design)

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