Abstract:
Actuator failures in dynamic systems result in worse performance as they are uncertain in
failure time and pattern. For example, many aircraft accidents can occur due to failures in
the operation of actuators, like aileron, elevator, and rudder. A Direct adaptive model
reference controller (D-MRAC) using Lyapunov theory is designed for an aircraft flight
control system (FCS) to guarantee good performance despite the actuator‟s performance
degradation or failures. The Direct MRAC control architecture is applied to the Boeing
747 aircraft in longitudinal maneuver. Numerical simulations are carried out to validate
suggested control method performance for aircraft due to actuator lock in place, loss of
actuator effectiveness and actuator hard over and hard under. The simulations are also
carried out with Linear Quadratic Regulator (LQR) controller and it is seen that direct
model reference adaptive controller (D-MRAC) successfully overcomes the actuator fault
as compared to the non-adaptive, optimal LQR controller
