The focus of the joint research work was on the development of system components for the detection of runtime defects in the hardware. The twist: The use of expensive special hardware can be reduced significantly. The solution centers on the redundant execution of safety-critical functions at the software level. The challenge in this regard was to design the system in such a flexible manner that it is able to fulfill its task for the application function transparently on a wide variety of execution platforms. Central properties such as the physical distribution, the degree of redundancy, the alignment of extensive input data, the process for comparing the results, as well as the response to defects had to be taken into account.
The resulting solution is a flexible software safety architecture that enables the use of non-safety hardware for safety-relevant requirements. The project team demonstrated its realizability with the help of a prototype implementation, taking extensive safety considerations into account. Among other things, the experts used the tool safeTbox developed by Fraunhofer IESE to examine the degree of diagnostic coverage of a selected architecture configuration. For the safety analysis they used integrated component fault trees to identify possible defect patterns and demonstrate the suitability of the implemented measures. In addition, the research team employed robustness tests through simulation in a virtual execution environment using the IESE tool FERAL. This allowed the researchers to assess further influences, which may result, for instance, from complex operating system functionalities or communication channels.
The solution will enter series production – an indication that Bosch is convinced of usefulness of the results. In addition, the research team will jointly register the concept as a patent.