Fault recovery for cascaded asynchronous sequential machines

In this study, the authors investigate the fault-Tolerant control problem of a cascaded asynchronous sequential machine (ASM) in which two ASMs subject to adversarial inputs constitute a cascade composition. The main objective is to develop a corrective controller that can diagnose and tolerate any unauthorised state transition occurring in the cascaded machine. In particular, the authors address fault-Tolerant control for two control configurations, one with a state feedback and the other with an output feedback. The existence condition for a controller is found to be different with respect to each feedback availability. The authors apply the proposed control scheme to robust operations of memory scrubbing modules in space-borne computers implemented on field-programmable gate array systems. Experimental results show the practicability of the proposed methodology.