Reliability and control theory: An integration approach for safety analysis

Abstract

This paper presents an integrated safety analysis methodology for safety critical systems. In first approach, known as evolutionary safety analysis, we describe system failure models through hierarchical system structure including different safety analysis techniques like Preliminary hazard analysis (PHA), Hazard and operability study (HAZOP), Fault tree analysis (FTA) and Failure mode and effect analysis (FMEA). In second approach, known as revolutionary safety analysis, we combine the results from the first approach for a systematic analysis of scenario based safety control. So far, these two-methodologies seen as two different competing paradigms and have been used separately one for the reliability theory and another for the system and control theory. In this paper, we describe their interrelations and how they can be bridged together for high level of safety. We exemplify our integrated methodology to the development of Green Line Metro System and evaluated the automation via formal verification techniques.