Fault tolerance in switched ASMs with intermittent faults

This study presents new results of fault recovery in switched asynchronous sequential machines (ASMs). The proposed strategy incorporates switching operations and corrective control to tolerate intermittent faults for which any recovery procedure is infeasible for finite time after initial fault occurrence. Each submachine constituting the switched ASM serves as a temporary substitution for the faulty submachine. The reachability of the switched ASM is analysed and a methodology is proposed to determine the existence condition for a corrective controller that achieves fault recovery in an asynchronous mechanism. Using the proposed scheme, the authors implement a fault-tolerant read-only memory controller for on-board computers on field-programmable gate array systems and validate its applicability through a case study.