STRUCTURAL DESIGN OF SYSTEMS WITH SAFE BEHAVIOR UNDER SINGLE AND MULTIPLE FAULTS

Handling of multiple simultaneous faults is a complex issue in fault-tolerant control. The design task is particularly made difficult by the numerous different cases that need be analyzed. Aiming at safe fault-handling, this paper shows how structural analysis can be applied to find the analytical redundancy relations for all relevant combinations of faults, and can cope with the complexity and size of a real system. Being essential for fault-tolerant control schemes that shall handle particular cases of faults/failures, fault isolation is addressed. The paper introduces an extension to structural analysis to disclose which faults could be isolated from a structural point of view using active fault isolation. An example and results from a marine application illustrate the concepts.