Analysis and design of guidance-strategy for dynamic soaring with UAVs

• Dynamic soaring is an effective method to extract energy from wind shear to reduce energy consumption and extend flight duration.
• The aim of this paper is to propose a simple method to generate the guidance strategy for autonomous dynamic soaring.
• The characteristics of optimal dynamic soaring trajectory can be described by the azimuth and the pitch angle.
• The crucial parameters which decide whether UAVs can perform dynamic soaring successfully are the strength of wind shear, the ratio of lift coefficient to drag coefficient, the current air speed of UAV, the pitch angle and the azimuth.

Dynamic soaring is an effective method to extract energy from wind shear to reduce energy consumption and extend flight duration. However, the design of the guidance-strategy for autonomous dynamic soaring is still suffering from the heavy computation load. In order to solve this problem, the aim of this paper is to propose a simple method to generate the guidance-strategy for autonomous dynamic soaring. Firstly, the flight path of dynamic soaring is modeled and solved by an open source optimal software named GPOPS. Secondly, the cycle of dynamic soaring is divided into four piecewise trajectories, and the characteristics of each are determined by some simple equations. Thirdly, the guidance-strategy based on the results of these equations is summarized. Simulation results indicate that the proposed guidance-strategy can present the characteristics of optimal flight very well, and it is practical and easy to be implemented by the on-board computer of Unmanned Aerial Vehicles for its simplicity.