Robust Finite-time Attitude Tracking Controller Design for Small-scaled Fixed-wing Unmanned Aerial Vehicles

This paper focuses on designing and implementing the robust finite-time attitude tracking controller for small-scaled fixed-wing UAVs subject to nonlinearities, parameter perturbation, modeling error, and gust wind disturbances. Time-domain system identification approaches are introduced to obtain the longitudinal and lateral dynamic models of fixed-wing UAVs. By the feedback linearization technique, a linear equation with equivalent disturbances is derived to describe the attitude dynamics, for which a new robust finite-time controller is constructed. Based on the backstepping methodology and signal compensation theory, the controller incorporates two parts: a non-smooth nominal part using the sign function to achieve the desired finite-time convergence property and a robust compensator to restrain the influences of equivalent disturbances. Finally, the identification experiments are conducted and the effectiveness of the proposed controller is demonstrated by the Hardware-in-loop simulation studies.