Biologically Inspired Dynamic Soaring Maneuvers for an Unmanned Air Vehicle Capable of Sweep Morphing

Abstract

Dynamic soaring is a versatile maneuver executed to acquire energy available in the atmospheric wind shears. In this paper, an innovative concept of integrating wing sweep morphing during dynamic soaring maneuver is proposed. An unmanned air vehicle (UAV) with standard wing–tail configuration is considered. The aerodynamic modeling is based on the empirical estimation procedure duly validated with numerical vortex lattice method (VLM). The dynamics of the UAV is modeled as a three-dimensional point-mass model with nonlinear wind shear. The trajectory optimization problem is formulated as an optimal control problem using Guass pseudospectral method. The comparison of wing sweep morphing ability during flight is compared with its fixed-wing counterpart. Typical performance parameters used for comparison between both configurations include minimum wind shear and aerodynamic efficiency. Results indicate significant reduction in the minimum wind shear requirement $$(24\%)$$ and considerable improvement in the aerodynamic efficiency ( $$24\%$$ drag reduction, $$10\%$$ less lift coefficient requirement, $$34\%$$ higher normalized energy and $$25\%$$ improved loitering performance). A great potential of further exploring and coupling different wing-morphing mechanisms to further extract potential benefits of dynamic soaring maneuvers is proposed. This investigation will serve as a baseline for the proof of concept that dynamic soaring can be extended to a morphing platform in achieving optimal performance.