Achieving affordability through fuzzy reasoning and control

One way to make a system more affordable is to reduce the number of redundant components. Reducing components while still maintaining a desired level of reliability requires that the functionality of the eliminated, redundant hardware be replaced with a lower-cost option. In this paper, we present a methodology that offers such an option on an aeropropulsion engine. This option is a low-cost secondary control unit with an intelligent logic that can be implemented as a part of the engine health monitoring unit. The low-cost, secondary control unit acts like a back-up control, when the primary control unit becomes faulty. The back-up unit relies on the models and logic stored in the monitoring unit to provide a reduced-envelope capability for the flight vehicle. The basis for the logic is fuzzy reasoning. The reasoning is initiated by observing the behavior of the engine before a fault is developed