Fault tolerant control systems design with consideration of performance degradation

In this paper, an integrated design for fault tolerant control systems (FTCS), with consideration of performance degradation, is proposed. The design objectives, specifications, performance measures, and the consideration of graceful performance degradation are investigated. Three intervals in FTCS and their associated performance characteristics axe presented. Guidelines for selecting reference models for the purpose of determining design specifications are discussed, a model-following adaptive design methodology is coupled with a jointly designed fault detection and diagnosis (FDD) scheme to achieve desired performance. The reconfigurable feedback controller is designed automatically using an eigenstructure assignment technique, while reconfigurable feedforward controllers are designed using a model-following methodology. The design objectives and the proposed integrated approach have been demonstrated and evaluated using an aircraft example