Reinitialization Issues in Fault Tolerant Systems

This paper is concerned with the reinitialization of fault tolerant systems in which detection and isolation (FDI) techniques are used, on-line, to identify and compensate for system failures. Specifically, we will focus on FDI techniques which utilize analytic redundancy, arising from a knowledge of the plant dynamics, by analyzing the residuals of a no-fail filter designed on the assumption of no failures. In these types of fault tolerant systems, system failures have to propagate through the no-fail filter dynamics in order to get detected. Therefore, the no-fail filter must be reinitialized after the isolation of a failure so that the accumulated effects of the failure are removed. In this paper, we will discuss various approaches to this reinitialization problem.