微型飞行器激光远程充电技术的基础研究

Micro Air Vehicle (MAV) is a kind of new developed aircraft in the nineties of the 20th century. It has widely potential applications in the areas of industry, commerce and military. In order to realizing longer endurance and farther flight distance, some techniques have been studied and applied to the design of MAV, which include increasing the life time and reducing the weight of battery, developing high power density battery and more efficient micro motor.So far, the techniques are not mature. In this proposal, we will introduce another new approach of wireless charging by laser to increase endurance capability for MAV.That is to provide electric power without wires for flying MAV from ground by using high intensity laser irradiating the solar cells pasting on the body of MAV. The power can be complemented momentarily during MAV flying in the space to prolong its flight time. So we shall concentrate on the study of fundamental problems about the beam reshaping of high power semiconductor laser，the attenuation of laser beam in air, laser receiving and photovoltaic conversion through theoretical analysis and experimental tests. The roles of photovoltaic conversion for different solar cells irradiated by high intensity laser will be investigated. And all of conclusions are helpful for improving the efficiency of energy transformation in the area of wireless power transmission technique of MAV.

微型飞机作为20世纪90年代出现的一种新兴飞行器，在工业、商业以及军事领域有广泛的应用前景，为达到长航时、远距离飞行的要求，目前采用的主要技术途径是研发高能量密度电池和节能微型电机，以达到提高电池使用寿命并减轻电池重量的目的。本项目创新性地提出采用另外一种途径增加其续航时间的设想，即采用高功率密度激光照射紧贴在微型飞机底部的光电池进行远程充电，为其在飞行过程中实时补充电力以达到延长续航时间的目的。为此，拟从大功率半导体激光束进行整形和传输损耗优化、光电池参数与激光参数匹配以及光电池表面制备抗反射结构等方面入手，探索不同材料、不同结构光电池对不同参数的强激光束进行光电转换的规律，为微型飞机实时远程充电技术中能量转换效率的提高提供有价值的研究成果。

微型飞行器Micro Air Vehicle (MAV)由于受携带电池重量的制约，其续航时间短的“瓶颈”一直未得到很好地解决。本项目基于该应用背景，借助于激光发射、传输及其与物质相互作用的理论和技术，开展了采用激光远程充电技术延长MAV续航时间方面的相关研究，分别研究了不同种类光电池对不同参数激光转换效率影响、高功率半导体激光束整形、激光束对运动目标识别跟踪等问题。结果表明：不同种类光电池（硅基、多元化合物等）对不同参数激光（波长、光功率密度、均匀性等）的转换效率有很大差别，在现有技术条件下，采用波长为808nm的半导体激光器照射砷化镓类光电池，可实现较高的光电转换效率（高达50%，获电能5W/cm2）；对由光纤输出的阵列型半导体激光束，采用光束匀化、准直等整形理论及数值模拟软件，通过分析与计算，优化相关参数，实验上得到了匀化率高于85%、发散角小于mrad、可用于远程高效电力传输的808nm准直激光束；采用双目摄像头识别、四象限或角锥镜反馈、二维转台或振镜扫描等多种技术结合，研发了两种激光束二维扫描跟踪控制系统，实现了充电激光束对移动目标的实时识别与跟踪。相关研究成果不仅为延长MAV的续航时间提供了有应用价值的技术支撑和关键数据，也为当今快速发展的远程无线充电需求提供了有借鉴价值的技术方法和参考途径。在该项目研究成果基础上，课题组与华为公司合作，进一步开展了激光为室内手机、平板电脑等移动用电负载充电的研究，也取得了一些进展，研发出一套目前已交付为华为公司；另有一种基于谐振反馈原理的激光充电方法研究还在进行中。