Self-Repairing Corrective Control for Input/Output Asynchronous Sequential Machines with Transient Faults

Fault-tolerant corrective control for input/output asynchronous sequential machines (ASMs) is studied in this article. In the present problem setting, not only the controlled ASM but also the corrective controller itself is vulnerable to transient faults. The fault outcome is aggravated when the transient fault occurs to the controller, since the adverse effect of the fault is propagated toward the controlled ASM. We first address a scheme of diagnosing transient faults by designing the state observer that induces the resultant faulty state based on the output burst. We then present the existence condition and design algorithm for a corrective controller that recovers the normal behavior of the closed-loop system against transient faults at the ASM, while achieving self-repair against those faults occurring to the controller. Hardware experiments on field-programmable gate array (FPGA) circuits are provided to validate the applicability of the proposed control methodology.