Database-driven Safe Flight Envelope Protection for Impaired Aircraft

In this paper, an online flight envelope protection system is developed and implemented on impaired aircraft with structural damage. The whole protection system is designed to be a closed-loop of several sub-systems, including system identification, damage classification, flight-envelope prediction and fault-tolerant control. Based on the information given by damage classification, the flight envelopes are explicitly retrieved and processed online from the database and fed into the fault-tolerant controller, which makes the protection system adaptive to a wide range of abnormal conditions. Simulation results show that with envelope protection, loss-of-control accidents are more likely to be prevented, since both the controller and pilots are aware of the shrunken flight envelopes after damage and excessive commands are restricted. In this way, the fault-tolerance of the impaired aircraft can be effectively enhanced.