Optimal shape design of an airship based on geometrical aerodynamic parameters

Abstract

Background Conventional airship mathematical modeling usually involves six coupled degrees of freedom and two inputs, namely tail and thrust. The current study focuses on aerodynamic modeling. The aerodynamic model is developed in 3D-space based on plane semi-empirical model of a symmetric airship. The model depends on the main geometrical parameters of the airship. The study introduces an optimal shape design of the airship. The objective function is established to reduce drag and the effect of side flow and increases both lift force and pitching moment. Three types of airship shape construction are investigated, namely NPL, GNVR, and Wang. Results MATLAB genetic algorithm toolbox is used to obtain the optimal shape. The population size is 50 and the number of generations is also 50 for NPL, GNVR and Wang shapes at each corresponding angle of attack $$(\alpha =\left[ -20^\circ ,20^\circ \right] )$$ ( α = - 20 ∘ , 20 ∘ ) and side-slip angle $$(\beta =\left[ -20^\circ ,20^\circ \right] )$$ ( β = - 20 ∘ , 20 ∘ ) . The shapes are compared to select the best fit within the operating range. To get the optimal shape, weighted averaging is performed on the optimal solution. Conclusion The GNVR geometric construction technique is the best method to generate the optimum shape of the airship in the presence of side-slip angle effect with the utilized objective function that reduces drag and side flow and increases lift and pitching moment.

Optimal Tracking Control for Underactuated Airship

“…Same conclusions were presented by Suiçmez [36]. These analyses led to use the first method of LQT controller with switching to the second method at the points of changing trajectory profile, see Figures 18,19…”

“…The airship 3D model built by Atyya et al [19], shown in Figure 6, with hollow hull and tri-motors as a propulsive unit will be used in the current study.…”

“…c. Aerodynamic Forces and Moments Semi-empirical aerodynamic equations were developed by Jones and DeLaurier [18] for uniform flow and extended to consider the side flow effect by Atyya et al [19] with introducing the flow angles, namely, the angle of attack (α), Eq. 13, and the side-slip angle (β), Eq.…”

“…Newton's second law (F = ma) is used to develop the transnational motion equations, while the rotational motion equations are derived from the conservation of the angular momentum (M = Ḣ) [8,9,10,11,12,13,14]. A semi-empirical aerodynamic model is developed for uniform flow [15,16,17,18] and extended to consider the side flow effect for axisymmetric airship [19].…”