Understanding HIL testing
HIL is a well-established and understood test methodology used in-vehicle validation. The primary benefit of using simulation and models is to enable engineers to iterate their designs more rapidly. To completely validate a full vehicle design, HIL testing is required at a wide range of component levels.
For example, when examining a seat, subcomponent testing would be used to verify the ECU’s function as it interacts with different loads, see figure 1 . System-level HIL testing might bring several motors together to test the operation of the seat as a whole. Multi-domain HIL testing is used to verify the function of the seat in combination with the infotainment system, which also can be used to control some of its function. Further down the line, the coordinated functions of adjustment, haptic feedback, heating, cooling, and infotainment input and display of the seat are tested to ensure safe and reliable operation. This is the purpose of the multi-domain HIL solution.
As vehicle systems are increasingly using complex electronic, intelligent, and interconnected systems to provide advanced safety and comfort features to vehicle occupants, performing system integration test using multi-domain HIL solutions is more critical than ever. This is because when systems come together, many unexpected behaviours can occur, which may be impossible to identify when testing in isolation, either at the component or sub-system level.
For example, multi-domain testing can reveal how the unexpected draw on a vehicle battery can compromise the performance of other electronics. Networking bottlenecks may also arise when multiple data-heavy systems like ADAS and powertrain are combined, resulting in a system slowdown. Even physical challenges can be revealed, such as grounding problems between ECUs that lead to unexpected values.
Finding such problems early in the design process, before even having a prototype vehicle for testing, can help engineers save valuable time, reduce costs, and avoid potential costly recalls for bugs otherwise not found by conventional testing.