Modelling and Simulation of Aerodynamic Parameters of an Airship

Abstract

The dynamic modelling of an airship is the primary requirement in designing and developing a control system for a particular application. Extracting/predicting/modelling the aerodynamic coefficients is a crucial step towards the modelling of an airship. There is a huge amount of literature on the aerodynamic modelling of airships which presents experimental as well as analytical methods. All these techniques require some experimental data such as the geometrical data, control derivatives, etc. In this work, we are investigating an analytical technique which can calculate the aerodynamic parameters for a high altitude airship. The complete airship model is implemented using the derived aerodynamic coefficients. A MATLAB R Simulink based simulation is used for the investigation. Nomenclature α Angle of attack, deg β Side slip angle, deg δ a Aileron deflection angle, deg δ e Elevator deflection angle, deg δ r Rudder deflection angle, deg η Throttle ratio γ, µ Angles along the wind axes, deg φ, θ, ψ Airship's Euler angles-roll, pitch and yaw, deg ρ Density of air, kg/m 3 b Wing span, m b z Point of action of buoyant force in z direction, m c mean aerodynamic chord, m C D , C L , C Y Coefficient of drag, lift and side force C l , C m , C n Coefficient of rolling moment, pitching moment and yawing moment d z Point of action of thrust in z direction, m I x , I y , I z Moment of inertia components about x, y and z axes, kg/m 2 I xz Product of inertia about y axis, kg/m 2 m Airship mass, kg m x , m y , m z Apparent mass components in the x,y and z axes, kg p, q, r Airship angular velocities along the roll, pitch and yaw axes, deg/s S Wing planform area, m 2 t, T Current simulation time and gust time period, s T m Maximum engine thrust, N u, v, w Airship linear velocities along the x,y and z body axes, m/s V Airship forward velocity, m/s V m , V g Mean wind and gust velocity, m/s x E , y E , z E Position coordinate in the earth frame, m CoG Centre of Gravity CoV Centre of Volume EOG Extreme Operating Gust LTA Lighter-Than Air