- Can you introduce yourself in a few words? …
- Can you explain the acronym HIL? …
- Can you also quickly explain MIL, SIL, DIL ? …
- Is there an alternative to HiL test benches? …
- What types of problems can HIL test benches solve?
New age Automotive ECU applications are complex systems. An insane amount of information needs to be processed in real-time and rendered to various other systems. An ADAS system, for example, uses an advanced algorithm to processes data from the cameras, radars, GPS and other sensors to assist the drivers in avoiding judgement errors while driving. Such a data-heavy system has to be fool-proof and to ensure that, the testing must be rigorous and comprehensive.
Testing such complex systems on a real vehicle to prove every possible use-case is not a viable option. It incurs huge overheads and it is very challenging to test every scenario. Moreover, performing the tests at the final assembly entails test-related changes that can seriously impact the schedule as well as the cost. Also, the entire assembled platform might not be available for testing at the required time.
Simulation happens to be the only plausible approach to such testing and thus arrives Hardware-in-Loop testing methods. Not only does it automate the testing process but also brings in the tests much early in the software development lifecycle.
While we make it sound very easy to have HIL Testing unravel the software defects without an assembled product, a lot actually goes into the process.
Let’s begin by understanding HIL Testing at a high level, followed with a detailed analysis of the HIL Test system and the testing process.
In the simplest terms, HIL Testing is a method to validate a software in a simulated environment where ECU functions can be tested without having the actual vehicle system. HIL Testing is used to validate the communication, system integration and the functionality aspect of automotive software.
Ideally, an ECU under test receives huge number of I/O signals that represent different functionalities. A comprehensive test means that all these functionalities are tested under the scenarios based on the requirements. So, what exactly conspires during HIL tests?
During HIL Testing, the ECU is connected to a Test System that mimics an assembled product (an engine, a body control module or even the entire vehicle system). It interacts with the input and the output of the ECU under test, as if it were an actual vehicle.
Using a HIL Testing software, different test scenarios can be created, and the output validated. Depending on the software requirements, the test coverage can be expanded without worrying about the cost and physical risk to the system.
What is HIL Testing in the Context of Automotive Application Development?
The ISTQB CTFL Automotive Software Tester certification is particularly helpful for automotive software testers who are planning to implement special automotive testing approaches in the near future. To pass the interview, you must prove your expertise in applying suitable test techniques, as per the changing requirements of the automotive standards. Moreover, you must also possess an advanced understanding of the virtual test methods including HiL, SiL, MiL, etc.
The interview panel will examine your mastery of several automotive activities, roles, techniques, and methodologies that are specific to the role of an Automotive Software Tester. There are some standard questions that you should be prepared for. Below is a list of common ISTQB® CTFL Automotive Software Tester interview questions and answers. Let’s get started!
Since 2008, ISO 26262 has covered functional safety standards for vehicles. It incorporates safety analysis methods that account for random and systematic errors in electrical and electronic systems, and it’s now broadly adopted worldwide. The automotive industry relies on software best practices outlined in ASPICE to reduce risk in connected cars.
Replacing a faulty computer system with a more efficient one can be a difficult and time-consuming process, but software development managers can help make the transition go smoothly. They do this by outlining various development stages, making sure everyone completes stages on time and in the correct order, and that the project is delivered as promptly and as bug-free as possible.
You may also go through our ISTQB® CTFL Automotive Software Tester Online tutorial to further strengthen your knowledge base. Our Free Practice Tests will further help attain your desired certification and become competent to your employers in an ever-changing job market.
Finding HIL Testing in the V-Cycle Diagram
In the software development lifecycle, HIL Testing is the step where the software validation is performed. As clear from the V-cycle diagram, it is executed against the software requirements which may comprise functional as well as safety requirements (ISO 26262 compliance development).
Unit testing and integration testing precede the stage where the software is ready to be validated keeping the target hardware in loop.
A model based development paradigm takes a different approach where Hardware-in-Loop testing is preceded by Processor-in-Loop (PIL Testing), Software-in-Loop (SIL Testing), and Model-in-Loop (MIL Testing).
Understanding a Typical HIL Test System
A HIL test system is at the heart of HIL testing. The simulation part of the testing that we mentioned earlier, needs an environment that can trick the ECU into believing that it is connected to a real vehicle.
The test system provides this environment. And for that purpose, it requires a gamut of software and hardware components. Let’s discuss them!
- Generate stimulus signals
- Manage the communication of the sensors and the actuators between DUT and Test System
- Manage current/voltage and optical I/O channels
The importance of I/O interfaces also lies in the fact that it has to make sure that the DUT must always behave in a way that it is controlling the actual hardware. Test System providers may provide both dedicated as well as configurable I/O interfaces.
- Test Case Scripting: The tool is required to create test cases using scripting language. Various scripting languages are used depending on the HIL Test system brand. For example, Vector VT System uses VTest Studio for writing test cases in CAPL script. On the other hand, DSpace uses Python for the same.
- ECU simulation: A software tool for simulating other ECUs in a vehicle is of the prime importance in an automotive HIL testing setup. The ECU under test might have to interact with other ECUs during its operation. And therefore, during the HIL testing all such ECUs need to be simulated.
In addition to these, there are components that manage power supply by simulating the battery and other auxiliary modules like load boards.
FAQ
What is HIL testing in automotive domain?
What is the difference between HIL and SIL?
Can automotive interview questions?
