High-level fault injection to assess FMEA on critical systems

Abstract

Embedded systems in critical applications are constrained by very strict standards, but safety analysis (e.g., Failure Mode and Effects Analysis, or FMEA) of these systems is often empirical and mainly relies on the experience of engineers. Performing empirical analyses on complex designs is a major challenge that leads engineers to make very pessimistic assumptions and consequently to over-design multiple countermeasures. Many fault injection techniques have been developed to evaluate the robustness of Register Transfer Level (RTL) hardware designs. With these techniques, robustness is evaluated by comparing the faulty circuit outputs with the circuit specifications or golden RTL fault-free simulations. However, these techniques are too circuit centered, and therefore do not account for the overall system specifications. In addition, with complex hardware designs, fault simulations become very time-consuming. In this paper, we present a new high-level fault injection approach taking into account the overall critical system specifications to extract acceptable circuit parameter ranges while speeding up the evaluation process. We describe a case study of a real airborne system. The critical parameter ranges are determined for the circuit. Then, these ranges are used to rapidly evaluate the robustness of each RTL block in the circuit.