Fault Tolerant Analysis of Automotive Systems

Over the years, Fault Tolerance has become the most sought-after requirement in high-availability or life-critical systems. Fault-tolerant electronic sub-systems are becoming a standard requirement in the automotive industrial sector as electronics becomes pervasive in present cars. The existing fault-tolerance analysis approach can handle quality faults emanating from loss of precision in signal values of automotive systems, in addition to logical faults. This analysis can aid the designer to identify where and how precision losses occur in both software and hardware components. This analysis is performed on operation-level (Simulink) models, and hence provides early detection of weak spots in the system. The existing approach uses two fault analysis methods in tandem: a faultinjection and simulation method is used which evaluates the quality degradation of output signals of the system, under specific testcases and faultscenarios; and a look-up table based approach, in which quality degradation of the complete system is obtained by a series of table lookups, which store the characterized quality degradation behavior of individual components. The LUT based method performs a quick but approximate analysis and yields better coverage with respect to quality behavior. The exhaustive analysis of quality fault-tolerance is a computationally intensive problem. So, we focus on improving the LUT based approach for performing fault tolerant analysis. In this thesis, we present a novel technique to perform characterization of components using multiple functional testcases that are quite varied and hence capture most of the component behaviour in various faulty scenarios. Improving the characterization methodology, leads to improved quality LUTs for each component, using which dynamic analysis produces much better results. We use our approach to characterize two systems, namely a Fault Tolerant Fuel Controller and an Anti-lock Braking System. Apart from this, we also suggest techniques for performing compaction of LUTs to satisfy time and storage requirements.