Model Verification at Default Simulation Snapshot Time

This example shows how to assert that bounds on the linear system characteristics of a nonlinear Simulink model, computed at the default simulation snapshot time of 0, are satisfied during simulation.

1. Open a nonlinear Simulink model. For example:

   watertank

2. Open the Simulink Library Browser by selecting View > Library Browser in the model window.

3. Add a model verification block to the Simulink model.

   1. In the Simulink Control Design library, select Model Verification.

      

   2. Drag and drop a block, such as the Check Pole-Zero Characetristics block, into the model window.

      The model now resembles the following figure.

      

   For more information on the blocks, see the Model Verification block reference pages.

4. Double-click the block to open the Block Parameters dialog box.

   

   To learn more about the block parameters, see the block reference pages.

5. Specify the linearization input and output to compute the closed-loop poles and zeros.

   1. To specify an input:

      1. Click adjacent to the Linearization inputs/outputs table.

         The Block Parameters dialog expands to display a Click a signal in the model to select it area.

         

      2. In the Simulink model, click the output signal of the PID Controller block to select it.

         The Click a signal in the model to select it area updates to display the selected signal.

         

      3. Click to add the signal to the Linearization inputs/outputs table.

         

   2. To specify an output:

      1. In the Simulink model, click the output signal of the Water-Tank System block to select it.

         The Click a signal in the model to select it area updates to display the selected signal.

         

      2. Click to add the signal to the Linearization inputs/outputs table.

         

      3. In the Configuration drop-down list of the Linearization inputs/outputs table, select Output for watertank/Water-Tank System: 1.

         

         Note   Because the Open Loop check-box for watertank/Water-Tank System : 1 is clear, the I/Os include the feedback loop in the Simulink model. The software computes the poles and zeros of the closed-loop system.

      4. Click to collapse the Click a signal in the model to select it area.

6. Specify bounds for assertion. In this example, you use the default approximate second-order bounds, specified in Bounds tab of the Block Parameters dialog box.

   

   View the bounds on the pole-zero map by clicking Show Plot.

   

7. Stop the simulation if assertion fails by selecting Stop simulation when assertion fails in the Assertion tab.

   

8. Simulate the model by clicking in the plot window.

   Alternatively, you can simulate the model from the model window.

   The software linearizes the portion of the model between the linearization input and output at the default simulation time of 0, specified in Snapshot times block parameter. When the software detects that a pole violates a specified bound, the simulation stops and the following windows appear:

   • Simulation Diagnostics window, reporting the block that asserts.

     

   • Model window, highlighting the block that asserts.

     

   The plot window displays the closed-loop pole-zero locations of the computed linear system. You can also view the bound violation in the plot.

   

Types of Linear System Characteristics for Verification

Model Verification at Multiple Simulation Snapshots

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