Robust SJA-Based Nonlinear Trajectory Tracking Control Using Unmanned Aircraft LPV Model

The flight trajectory of unmanned aerial vehicles (UAVs) can be significantly affected by external disturbances such as turbulence, upstream wake vortices or wind gusts. These effects present challenges in ensuring UAV flight safety, and addressing these challenges is of critical importance for integration of unmanned aerial systems (UAS) into the National Airspace System (NAS), especially in terminal airspace. To address these challenges, this paper presents a robust nonlinear control method, which can be proven to achieve reliable UAV

trajectory and altitude regulation in the presence of unmodeled external disturbances and model uncertainty. The proposed control method focuses on applications involving small UAVs equipped with arrays of synthetic jet actuators (SJA). The control design presented in this paper extends previous research results by demonstrating asymptotic (zero steady-state error) altitude regulation control in the presence of unmodeled vertical wind gust

disturbances. To address the practical considerations involved in small UAV applications with limited computational resources, the proposed control method is designed with a computationally simplistic structure, without the requirement of complex calculations or function approximators in the control loop. Proof of the theoretical result is summarized, and detailed numerical simulation results are provided, which demonstrate the capability of the proposed nonlinear control method to asymptotically reject wind gust disturbances and parameter variations in the state space model. Side-by-side simulation comparisons with a standard linear control method are provided for completeness.