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Code Generation Verification Workflow with Simulink Test

This example uses:

Open Script

Perform code generation verification for a model. Copyright 2015 The MathWorks, Inc.

This example shows how to perform code generation verification (CGV) for a model using test harnesses, Test Sequence blocks and the test manager. Switch to a directory with write permissions.

mdl =“sltestFuelRateControlExample”; open_system(mdl);

Description of the Model

This example uses a model of a fuel-rate controller for a gasoline engine. The controller uses four sensors from the system to determine the proper fuel rate. The four sensors used from the system are throttle angle, speed, EGO and manifold absolute pressure [MAP].

The model uses three subsystems to calculate the fuel rate using the sensor inputs:control logic,airflow calc, andfuel_calc. The core control logic is implemented in the Stateflow® chart namedcontrol_logic. The control logic handles single sensor failures and engine overspeed protection. If a single sensor fails, operation continues but the air/fuel mixture is richer to allow smoother running at the cost of higher emissions. If more than one sensor has failed, the engine shuts down as a safety measure, since the air/fuel ratio cannot be controlled reliably.

The model estimates the airflow rate and multiplies the estimate by the reciprocal of the desired ratio to give the fuel rate.

Opening the Test Harness

A Test Harness namedfuel_rate_control_cgv已创建的吗entire model. The harness can be opened by clicking on the perspectives pullout icon in the bottom-right corner of the model canvas and choosing thefuel_rate_control_cgvthumbnail. Ensure that the top level of the model is in view before you click on the icon. Alternately, the harness can be opened using the following API:

sltest.harness.open(mdl,'fuel_rate_control_cgv');

的建模Plant

The test harness has been modeled as a closed-loop test with a Test Sequence block to drive fuel-rate controller. The computedfuel_ratefrom the output of the controller is used to drive a model of the gasoline engine. The fuel rate combines with the actual air flow in theEngine Gas Dynamicssubsystem to determine the resulting mixture ratio as sensed at the exhaust. Feedback from the oxygen sensor to the Test Sequence block provides a closed-loop adjustment of the rate estimation in order to maintain the ideal mixture ratio.

Notice that the plant has been modeled in the test harness instead of the main model. The main model is free of extraneous clutter so that code can be easily built for an ECU with minimal changes to the model.

Modeling Sensor Failures

The Test Sequence block namedSequence Sensor Failuresmodels various sensor failure and engine overspeed scenarios. It accepts feedback from the plant and drives the controller with sensor data. This modeling pattern allows the Test Sequence block to control the feedback signals received by the Controller block and function as a canvas for authoring test cases. Open the Test Sequence block to see the modeled test scenarios.

open_system('fuel_rate_control_cgv/Sequence Sensor Failures');

Test Scenarios

For the first 10 seconds of simulation, the test is in stabilization mode, where the closed loop inputs from the plant is passed through to the controller. The throttle and speed inputs are set to nominal values that are within the normal operating envelope of the controller. TheStabilize_Enginestep models this state.

The Test then steps through the following modes:

  1. Test_Overspeed: The throttle is ramped from 30 to 700

  2. Reset_To_Normal_Speed: The throttle is ramped down to 400

  3. Test_EGO_Fault: Simulate failure for 3 sec, then return to normal state

  4. Test_Throttle_Fault: Simulate failure for 3 sec, then return to normal state

  5. Test_Speed_Fault: Simulate failure for 3 sec, then return to normal state

  6. Test_Map_Fault: Simulate failure for 3 sec, then return to normal state

  7. Test_Multi_Fault: Simulate MAP and EGO failure for 3 sec

  8. Reset_MAP: Normalize MAP sensor, and simulate just EGO failure for 3 sec

  9. Reset_To_Normal: Terminate the test

Test Assessments

The Test Sequence blockAssess Controllerverifies the controller output for the various test cases modeled by theSequence Sensor Failuresblock. The following assessments are modeled:

  1. Assert that the fueling mode is in热身mode for the first 4.8 seconds

  2. Assert that fueling mode switches toOverspeedmode when the actual speed exceeds 628

  3. Assert that the fueling mode is not inSingle_Failuremode when multiple sensors have failed.

open_system('fuel_rate_control_cgv/Assess Controller');

Running a Simulation

Simulate the test harness by clicking Play in the toolstrip and observe the fuel_rate and air-fuel ratio signals in the scope. Alternately, run the following command:sim('fuel_rate_control_cgv')

Notice that no assertions trigger during the simulation, which indicate that all assessments modeled inAssess Controllerpass.

Configuring a back-to-back Test in the Test Manager

As part of code generation verification (CGV) for the controller system, it is important to assert that the functional behavior of the controller is same during normal and software-in-the-loop (SIL) simulation modes. The test manager is used to perform this verification.

Use the functionsltestmgrto open the test manager and load the example test file using the function:sltest.testmanager.TestFile('sltestFuelRateControlComparisonTestSuite.mldatx')

的建模Test Case

The equivalence test has been configured in the test manager so that the controller is simulated in normal and SIL mode and the numerical results are compared between these two runs. Explore the structure of the test case by clicking on different nodes of the test hierarchy in theTest Browser.

Running the Test Case

Run the test in the test manager using the functionsltest.testmanager.run.

Alternately, In the test manager, select theCGV Test1node in theTest Browserpane and clickRunin the toolstrip. The pass/fail result is available in theResults and Artifactspane.

Creating the Report

A report can then be generated to view the result of the equivalence test. Use the following commands to generate the report. You can also launch the report after creation using the API with theLaunchReportoption set totrue.

sltest.testmanager.report(cgvresult,'cgvresult.zip','IncludeTestResults',int32(0));
close_system(mdl, 0); clearmdl;