An Integrated Approach to Fault Accommodation in Fuzzy Discrete-Event Systems

This paper considers the problem of fault accommodation in complex safety-critical discrete-event systems described by the fuzzy finite state automaton model. The problem is solved by forming control that ensures complete decoupling from fault-induced effects. The fault-tolerant control scheme contains several channels activated depending on the diagnosed fault. Each channel includes two main blocks: 1) an auxiliary deterministic finite state automaton (observer) estimating the fuzzy vector of possibilities of system transitions to various states and 2) a converter forming the input of the controlled system based on a new external input and the observer state. An integrated approach (the pair algebra of fuzzy coverings) is proposed to describe the blocks and the new input. A distinctive feature of this approach is the joint use of mathematical constructs of the pair algebra of coverings (system of sets) and fuzzy logic.