Ducted fan UAV system analysis and fuzzy controller

Abstract

In this thesis, Ducted-Fan Uninhabited Aerial Vehicle(UAV), one of the Vertical Takeoff and Landing vehicles(VTOL), is studied. First of all, it is introduced what VTOL is and then, the differences from other VTOL and ucted-Fan UAVs and the major characteristics are dealt with. Among many ducted-fan models, Helispy is adopted as a simulation model. complex 6-DOF(Degree of Freedom) dynamic equations, which include aerodynamic acteristics due to unusual appearance, are derived. The model is separated to 4 parts such as fuselage, rotor, duct, and control surface. Each force and moment is added to obtain total force and moment. For understanding acteristics of the system, trim points are found by changing the forward velocity from 0 fps to 10 fps. Then, major characteristics such as change of attitude and pitch moment etc is considered. As the highlight of the acteristics, duct effects, forces, and moments by duct are investigated. Next, for analyzing the dynamic characteristics, nonlinear dynamic equations are linearized at each trim point. Then, from the transition matrix which is generated by linearization, eigenvalues and eigenvalues are obtained to analyze Longitudinal and Lateral-directional mode stability. In addition, relation of the damping derivatives due to symmetric appearance is found and effects of each other are investigated. Since simulation model is not perfectly correct, effects due to uncertainties are analyzed in each mode. Because of a symmetric appearance, while the vehicle moves forward, the vehicle has different haracteristics from hovering characteristics. The faster it moves, the more different figure it has. Considering hese characteristics, Takagi-Sugeno fuzzy gain scheduler is designed. Transitional simulation is performed by using this controller.