This article studies multiple unmanned aerial vehicles (multi-UAVs)-enabled wireless-powered Internet of Things (IoT), where a group of UAVs is dispatched as mobile power sources to charge a set of ground IoT devices. Different from the conventional radio-frequency (RF) wireless power transfer (WPT) systems, magnetic resonance-coupled (MRC) WPT systems can guarantee high power transfer efficiency without the complete alignment, which is remarkable. In this article, we extend the charging range by the wired connection between the energy receiving systems and IoT devices. Due to the restriction of carriable energy on the UAVs, designing the shortest possible trajectory for each UAV is necessary. We formulate it as a multidepots multi-UAVs trajectory optimization problem, jointly with constraints of the UAV's energy capacity and the area of the target region, to maximize the resource utilization of UAVs. To tackle this nonconvex problem, we decompose it into two subproblems, i.e., hovering locations selection and multi-UAVs trajectory optimization. For the first subproblem, we propose two approximation algorithms to obtain the near-optimal solution in the sparse networks. Then, we adopt a heuristic algorithm, a memetic algorithm-based variable neighborhood search (MAVNS), to achieve the quasioptimal trajectory rapidly. Finally, extensive numerical results are provided to evaluate the performance of the proposed algorithms. New insights are investigated on the estimation of feasibility that whether the given UAVs with energy capacity constraint can fully charge ground IoT devices within open areas.

中文翻译：

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无人机辅助无线供电物联网的自适应和可扩展能源供应机制


本文研究了支持多架无人机（multi-UAV）的无线供电物联网（IoT），其中派遣一组无人机作为移动电源为一组地面物联网设备充电。与传统的射频（RF）无线功率传输（WPT）系统不同，磁共振耦合（MRC）WPT系统无需完全对准即可保证高功率传输效率，这一点非常引人注目。在本文中，我们通过能量接收系统和物联网设备之间的有线连接来扩展充电范围。由于无人机携带能量的限制，有必要为每架无人机设计尽可能短的轨迹。我们将其表述为多基地多无人机轨迹优化问题，结合无人机能量容量和目标区域面积的约束，以最大化无人机的资源利用率。为了解决这个非凸问题，我们将其分解为两个子问题，即悬停位置选择和多无人机轨迹优化。对于第一个子问题，我们提出了两种近似算法来获得稀疏网络中的接近最优解。然后，我们采用启发式算法，即基于模因算法的变量邻域搜索（MAVNS），快速获得准最优轨迹。最后，提供了大量的数值结果来评估所提出算法的性能。研究了对具有能量容量限制的给定无人机是否可以在开放区域内为地面物联网设备完全充电的可行性估计进行了新的见解。