Archive Newsletter 2015 ()

New Test System to Secure Interconnected Safety Control Units

Trace-based testing using a HIL test bench with ReSiMa

To boost the effectiveness of airbags, reversible belt tensioners and electronic pedestrian protection systems, passive safety systems are being increasingly combined with active advanced driver assistance systems. This allows them to activate more quickly and in a more targeted manner, as the systems can gain access to the information gathered by other sensors (e.g. emergency brake assistants) on a vehicle’s environment as early as in the pre-crash phase. These new system dependencies, however, must be secured as early as possible and throughout the entire vehicle.

IPG Automotive has developed a new test system that allows the data exchanged between different sensors via bus systems in Hardware-in-the-Loop driving tasks to be tested and optimized. A unique aspect of this new HIL solution, called ReSiMa (Replay, Simulate, Manipulate), is that the safety control unit (SCU) to be tested is stimulated with real pre-crash and crash data in real time. Another special feature and technical achievement is the FPGA-based emulation of SPI sensors, which allow real crash sensors in the vehicle to be replaced. This enables the test system to reconstruct all sensor functions.

The RealtimeMaker-based system performs three main tasks during testing:

  • Replay: Collected crash data (e.g. from real accidents or crash tests) from a crash database are fed into the HIL system. The SCU in question is supplied with the required data from the collected bus and sensor trace files in real time using intelligent I/O (such as CAN, LIN, FlexRay, SPI, PSI5), allowing collected bus traces to be imported and replayed in sync with the accompanying sensor data.
  • Simulate: The SCU receives simulated data from RealtimeMaker.
  • Manipulate: Furthermore, the data and signals on the relevant communication buses can be manipulated systematically and in real time. This enables the values from existing data sets to be set to specific accident parameters without having to perform new test runs to generate crash data.

Within the context of ISO 26262, ReSiMa can be used to automatically test safety-critical functions up to ASIL Level D. If the test system is connected to CarMaker, the SCU can be tested in combination with a complete virtual vehicle and traffic environment (including other road users, pedestrians etc.). This allows the systems to be secured not only in scenarios that meet Euro NCAP requirements, but also in accident scenarios of a much greater complexity that go beyond standardized crash tests.

CarMaker is currently being expanded to include the real-time-capable, biomechanical vehicle-occupant model IPGVivo. IPGVivo simulates the movements of vehicle occupants in the pre-crash phase. In combination with ReSiMa, the vehicle-occupant model can be used to further improve the activation algorithms in occupant protection systems. This enables the optimal time sequence of belt tensioners and airbags to be tested and secured for various accident scenarios and vehicle occupant types.