Equilibrium Positions for UAV Flight by Dynamic Soaring

Abstract

Dynamic soaring is a special flying technique designed to allow UAVs (unmanned aerial vehicles) to extract energy from wind gradient field and enable UAVs to increase the endurance. In order to figure out the energy-extraction mechanisms in dynamic soaring, a noninertial wind relative reference frame of aircraft is built. In the noninertial frame, there is an inertial force which is created by gradient wind field. When the wind gradient(GW)and the components of airspeed(vzvx)are positive, inertial force(F)makes positive work to the aircraft. In the meantime, an equilibrium position theory of dynamic soaring is proposed. At the equilibrium positions, the increased potential energy is greater than the wasted kinetic energy when the aircraft is flying upwards. The mechanical energy is increased in this way, and the aircraft can store energy for flight. According to the extreme value theory, contour line figures of the maximum function and the component of airspeed(vz)are obtained to find out the aircraft’s lifting balance allowance in dynamic soaring. Moreover, this equilibrium position theory can also help to conduct an aircraft to acquire energy from the environment constantly.

PERHITUNGAN JARAK JANGKAU MAKSIMUM PESAWAT UDARA NIR AWAK BPPT UNTUK MISI STRATEGIS DETERMINING = THE MAXIMUM FLIGHT RANGE OF BPPT’S UAV FOR STRATEGIC MISSION

“…Penambahan jangkauan terbang sebenarnya dimungkinkan dengan berbagai cara, misalkan dengan autonomous soaring dan pengisian bahan bakar di udara (Lawrance 18) ), dynamic soaring (Zhu dkk. 26) ), trajectory optimization (Manickavasagam dkk. 19) ), serta gliding flight (Dao dkk.…”

Albatross-Like Utilization of Wind Gradient for Unpowered Flight of Fixed-Wing Aircraft

“…In the dynamic soaring system represented by Equations (4)-(6), the equilibrium points are defined by the constant velocities that can be maintained by the aircraft, namely, [39] proved the calculability of the equilibrium points of a dynamic soaring system. The equilibrium also indicates the force balance during flight through a gradient wind.…”

“…Should an ascending equilibrium point occur, the aircraft could utilize it for sustainable climbing. Zhu et al [39] proved that the sufficient and necessary condition for the existence of an ascending equilibrium point was the satisfaction of the following inequality:…”

“…In addition, we developed a method for utilizing a wind gradient for sustainable climbing [39] in unpowered flight. Simulation experiments and analysis were used to An albatross flying over the sea to obtain extra airspeed.…”

Unmanned Aerial Vehicles for Photogrammetry: Analysis of Orthophoto Images over the Territory of Lithuania

“…The flow of the air causes the wind speed to increase with increasing height above the ground. The wind blows along the negative direction ofaxis, the positive -axis points to the sky, and the direction of -axis is dependent on right-handed rule [22]. The relation between wind speed and height above the surface is described in the articles [23].…”