Adaptive flight control with constrained actuation

In this paper adaptive flight control in the presence of actuator constraints is considered. Using a quaternion-based approach, the saturation problem can be moved from the plant to the reference trajectory, such that the reference trajectory will diverge from its desired trajectory while the actuators are in saturation. This ensures that the adaptive update laws are not affected by the saturation of the actuators. The underactuation of the aircraft is mapped to a rotation problem using linear filters, which in essence decouples the rotational and translational dynamics such that the controllers can be derived independently of each other. Simulations have been performed where the aircraft tracks a series of waypoints, and it shows good performance even in the presence of unknown aerodynamic forces and moments.