Adaptive flight control of an aircraft with actuator faults

Actuator failures in safety critical flight control systems may cause severe system performance deterioration as they are uncertain in failure time and pattern. Each year, many aviation accidents occur because failures in the operation of control surfaces, such as elevator, aileron and rudder cause undesired response thus deviating from the normal flight trajectory. In this paper, a direct adaptive model reference controller (D-MRAC) using Lyapunov theory is designed for a commercial aircraft linear model in order to guarantee good performance despite the actuator´s performance degradation or failure. The Direct MRAC control architecture is applied on the longitudinal dynamics of B747-100/200 aircraft. Numerical simulations are performed in order to verify the performance of the proposed controller for the aircraft in the presence of actuator stuck. The simulations are also carried out with Linear Quadratic Regulator (LQR) controller and it is seen that the direct model reference adaptive controller (D-MRAC) successfully overcomes the actuator faul t as compared to the non-adaptive, optimal LQR controller.