On-line multiple-model based fault diagnosis and accommodation

Much research attention has been done on fault detection and diagnosis, but little on "general" failure accommodation. Due to the inherent complexity of nonlinear systems, most model-based analytical redundancy fault diagnosis and accommodation studies deal with linear systems with simple faults. In this paper, online fault accommodation control under catastrophic system failure is investigated. The main interest is in unanticipated component failures. Through discrete-time Lyapunov stability theory, necessary and sufficient conditions for online stability and performance under failures are derived and a systematic procedure and technique for proper fault accommodation under the unanticipated failures are developed. A complete architecture of fault diagnosis and accommodation has also been presented by incorporating the developed intelligent fault tolerant control framework with a cost-effective fault detection scheme and a multiple-model based failure diagnosis process to efficiently handle the false alarms and the accommodation of both the anticipated and unanticipated failures in online situations