Fault tolerant robust flight control system design

In this dissertation, an integrated fault-tolerant control system approach which can cope with asymmetric elevator failures is studied. To achieve this goal, the F-16 aircraft is taken as an example platform. A detailed nonlinear dynamic model of this aircraft is obtained first. In the F-16 aircraft, the elevator surfaces are in two parts, right and left, and can move independently. Therefore, to obtain a more realistic and difficult failure scenario, it is assumed that the elevator is asymmetrically defective. For such failure scenarios, it has been shown that the conventional controller approach cannot cope with the failures. Then, this problem is solved by the designed H_∞ based fault-tolerant controller. However, comparing the conventional controller and the fault-tolerant controller in terms of computational complexity, the conventional controller can operate at very high cycle rates. Since it is relatively unlikely that a failure occurs on the aircraft, an integrated fault-tolerant control system approach using this advantage of the conventional controller is proposed. In this approach, a failure detection system is designed which continuously monitors the failure condition. In the non-failure condition, the conventional controller operates. If a failure occurs, the fault-tolerant controller is activated.