Coordinated Disturbance Observer-Based Flight Control of Fixed-Wing UAV

In this brief, a novel coordinated disturbance observer (CDO) is proposed to tackle the disturbance which affects the stable flight of a fixed-wing unmanned aerial vehicle (UAV). The above CDO is composed of multiple disturbance observers which have a basic form and depend on the designed coordinated variables. Due to the above special structure of the CDO, for one thing, the requirement of positive definiteness of the observer gain posed on a single disturbance observer is removed in the CDO. For another, the performance of the CDO can be enhanced by weighting multiple small disturbance observer gains. Via the Lyapunov function method, not only the decay rate and stable region of disturbance estimation error (DEE) of the CDO for the fixed-wing UAV are analyzed, but also the stability criteria of DEE and tracking error are given. Finally, the effectiveness of the proposed CDO is verified through the simulation of flight control of a fixed-wing UAV.