变加速无人机移动中继能效性能研究

Research on energy-efficiency of mobile relay of UAV with variable acceleration

针对基于直线轨道的固定翼无人机中继能效问题,文中提出一种无人机变加速飞行方案。该方案假设无人机飞行在固定高度且有足够大的数据缓冲区,通过联合优化时分双工无人机中继的收发时间分配及飞行加速度,实现对中继系统的能效最大化。对于无法直接求解的联合优化非凸问题,首先利用分步优化方法,分别对收发时间分配函数和无人机加速度进行优化。对于收发时间分配函数优化问题,将其转化为线性规划问题直接求解;对于加速度优化问题,取其目标函数的下界,将非凸目标函数转化为凸函数,并提出一种连续凸逼近的迭代算法对其进行求解。实验仿真分析了无人机移动中继不同加速度、任务量、源目的间距及收发时间分配对系统能效的影响,验证了算法的有效性;通过与匀速、匀加速等方案的对比,证明所提变加速飞行方案具有更高的能效性能。

In allusion to the relay energy-efficiency of fixed wing UAV(unmanned aerial vehicle)based on rectilinear orbit,a flight scheme of UAV with variable acceleration is proposed.In this scheme,it is assumed that the UAV flies at a fixed altitude and has a large enough data buffer.The energy efficiency of the relay system is maximized by jointly optimizing the transceiving time allocation and flight acceleration of the time division duplex UAV relay.For non-convex joint optimization problems that cannot be solved directly,the step by step optimization method is used to optimize the transceiving time allocation and flight acceleration respectively.For the optimization problem of transceiving time allocation function,it is transformed into a linear programming problem and solved directly.For the acceleration optimization problem,the lower bound of the objective function is taken,the non-convex objective function is transformed into the convex function,and an iterative algorithm of continuous convex approximation is proposed to solve it.The effects of different acceleration,task load,source destination spacing and transceiving time allocation of UAV mobile relay on system energy efficiency are analyzed by means of the numerical simulation.The effectiveness of the algorithm is verified.It is proved that the proposed variable acceleration scheme has higher energy-efficiency performance in comparison with the schemes of the uniform speed and uniform acceleration.