THREE DEGREE OF FREEDOM AIRCRAFT MODEL FOR UNMANNED AERIEL VEHICLES
This paper presents a three-degree of freedom (3 DOF) aircraft mathematical model of an unmanned aerial vehicle (UAV). Stability and control analysis are performed for a vehicle with specifications: wing span (6.10 m), aspect ratio (23), fuselage length (2.44 m), fuselage diameter (0.23 m), maximum take-off weight (40.82 kg), operating speed-cruise (61.73 m/s), cruising altitude (609.6 m), power require-cruise (600 W), operating speed-dash (20.58 m/s), power required-dash (5000 W) and Endurance (15 hours). A model is developed in a Matlab/Simulink environment by utilizing the conservation of linear and angular momentum equation of motion for aircraft design. The model is designed to predict static and dynamic behavior of a
designed UAV. A Class I weight analysis is performed in Advanced Aircraft Analysis (AAA) software developed by DarCorporation to determine the component weight of the UAV. A 2D aerodynamic analysis of the airfoil is performed using XFRL5 to predict the sectional lift, drag and pitching coefficients of the selected airfoil. Subsequently, the entire UAV polar is simulated in XFLR5 by representing the UAV weight by component masses. The 3 DOF aircraft model predicts the behavior of the UAV for zero and negative 3 elevator deflection. The longitudinal dynamic stability of the UAV is determined.