An Optimal Energy Absorption and Utilization Design for Deformable/Reconfigurable Modular Solar-Powered UAVs in Near Space

Maximizing the absorption and utilization of solar energy is a bottleneck issue and hot research concern for high-altitude long-endurance (HALE) solar-powered UAVs (SP-UAVs). This paper investigates the overall design and task optimization for a deformable/reconfigurable SP-UAV platform that utilizes its modular characteristics to optimize the overall solar absorption and structural weight while maximizing its mission utility. First, we establish the energy absorption/consumption model, the aerodynamic model, and the subsystem mass prediction model. Based on these models, the overall parameter design and optimization scheme of a modular SP-UAV is proposed by using heuristic intelligence algorithms. The results show that the loading ratio of the deformable modular SP-UAV increases from 8.2% to 9.8%. Then, the flight processes in both the deformed and the reconfigured cases are verified under task-oriented scenarios. Simulation results indicate that compared with comparable benchmarks with conventional layouts, deformable SP-UAVs are capable of increasing the feasible zone from 72 to 142 days. Additionally, the separation and recombination points are optimized and determined at specific latitudes and dates. A performance analysis shows that separation in the daytime can multiply, thereby increasing the flight range, although the feasible zone shrinks with increasing UAV unit number.