Validating a Throttle Body Model

This example shows how to use Simulink to interact with SystemTest. The Simulink model characterizes a throttle. The test varies the mass of the throttle, the damping of the throttle, and the stiffness of the throttle. This example:

  • Shows how to override a Simulink block's parameters.

  • Shows how to map data to SystemTest using To Workspace blocks.

  • Illustrates the use of Limit Checking in a test.

Establish a Baseline for Comparison

In the Pre Test, data that was previously acquired is read and used as a baseline for comparison.

Vary the Simulink Parameters

A Simulink element is used to execute the following model for every main test iteration:


In order to vary the parameters of interest, select the 'Throttle' block in the model, then in SystemTest, create a model override for the "Selected Block's Parameter". Now select the 'Mass' as the Simulink Data to be overridden, and assign the Test Vector Mass as the overriding value. Repeat for the additional Block Parameters of interest.

Data Analysis

The norm of the position data is computed, and compared to a preset limit to determine if the model performance is acceptable. As each main test iteration is executed, the Simulink data is mapped to the Test Variable position_sim. The Test Vector, position_sim, is then compared with the position_mean that was computed as a baseline to compute the norm of the Simulink signal, position_norm.

The position_norm is then compared to a threshold value in the Limit Check element to determine whether the model simulation performance for the given iteration is acceptable.

Opening the Test

Use the systemtest function to open the test.


Open the example in the SystemTest desktop.

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