Enhancing the aircraft's stability and controllability against actuator faults using robust flight control

Actuator faults reduce the control power of an aircraft, which affects the stability and performance of automatic closed-loop operation. This paper addresses the fault-tolerant flight control problem using robust optimal technique. Moreover, it aims to investigate the limits of a linear-based robust controller working on a high-fidelity nonlinear aircraft simulation. The lateral dynamics of a business jet aircraft is considered in this work. Actuator faults are represented as an uncertainty in the input to the system. A mathematical framework that handles the faults and meets stability and tracking requirements is obtained. By designing the control law, deliberately tuning the weighing elements, and solving for an optimal controller, a robust solution is obtained. It was then tested in a nonlinear six degree of freedom simulation environment.