Optimal self-diagnosis policy for gas turbine engine FADEC

摘要

FADEC (Full-Authority Digital Engine Control) is widely adopted for gas turbine engine controllers because of its high performance. To acquire the high performance reliability, almost all FADECs are hot stand-by, multi-redundant systems. In such system, the failed unit can be detected by self-diagnosis and the optimal unit is selected to hold their outputs normal. For self-diagnosis, the data communication line is settled and each unit in the system can exchange data among them. However, such diagnosis may become the burden for CPUs of units when it is performed so frequently. This paper considers the self-diagnosis policy for dual-redundant and triple-redundant FADECs. The self-diagnosis is performed at every n-th control calculation cycles. Introducing expected cost, an optimal n* which minimizes it is considered. Numerical examples are given when the reliability function is exponential.