Aircraft robust flight tracking control against actuator efficiency faults

Robust control design against uncertainties is an important matter particularly for safety-critical systems such as the aircraft. Uncertainties, which resulted from uncertain parameters of the system or unmodelled dynamics, affect the stability and performance of the system. This paper presents a fault-tolerant control scheme for a multi-variable aircraft dynamics using robust controllers. Robust optimal H_∞ and μ-synthesis control methods have been investigated. The work includes the development of frequency-based weighting functions to handle the trade-off between the robustness and performance features of the system. For each controller, the structure of the closed loop system is designed and the optimisation problem that conveys the design requirements is obtained. The scheme was simulated and tested against actuators loss of effectiveness faults. Results showed satisfactory implementation towards the aircraft stability and performance requirements.