非合作目标在轨服务最终接近段视觉导航算法

为解决在轨服务最终接近段传统单目视觉相对导航方法受相机视场限制以及非合作航天器无法设置人工靶标的问题,提出了以非合作航天器太阳帆板三角形支架的部分结构为测量目标的视觉相对导航算法.首先,设计了"自拍杆"相机安装结构和相机实时标定方案,给出了视觉相机安装角的计算方法;然后,基于逆投影原理构建满足三角形支架实际空间几何构型约束的优化模型,采用蚁群搜索算法求解特征点的景深,并应用绝对定位方法估计航天器之间的相对位置和姿态;最后,以非合作航天器在轨服务最终2 m~0 m的接近段为背景进行数学仿真,在相对距离小于1 m时,航天器之间的相对位置和相对姿态确定精度分别优于3 mm和0.2°,验证了算法的有效性和可行性.数学仿真结果表明:该相对导航方案可行,导航算法具有较高的精度,且相对导航的精度随着航天器之间的相对距离的逐渐减少而逐渐提高;同时,该算法对投影点测量误差具有较好的鲁棒性,在投影点测量误差较大时仍具有较高的精度.     

高空无人机自动加油对接过程轨迹控制研究

针对无人机在高空自动加油对接过程中容易出现偏差的问题,提出了无人机空中自动加油精准对接的优化控制方案,研究并分析了影响加油锥管与受油接口快速准确对接的主要因素,通过运动轨迹生成器对浮锚加油锥套的运动轨迹进行模拟,无人机的自动飞行控制系统根据轨迹跟踪曲线对无人机的飞行姿态进行调整,引导无人机的受油接口与加油锥管进行精确对接,整个飞行轨迹跟踪控制过程优化了复杂高空环境中无人机加油对接的精准性;通过仿真实验表明,该高空无人机加油对接引导方法提高了空中管口对接的速度与抗干扰能力,可以满足各种复杂高空环境的无人机加油任务。     

遥感航天器在轨结构微变形光纤监测技术发展综述

对地、对天观测航天器在深空和极地探测、军事侦查、国土资源测绘、地质与农业灾害监测、海洋观测、气象观测和环境监测等系关国民经济社会发展的重要领域都发挥着关键作用。遥感航天器在轨结构受空间极端温度变化、重力、碎片冲击和疲劳等因素作用会产生微变形,在轨微变形监测对保障遥感航天器功能指标实现和系统可靠性及寿命有重要作用。光纤监测技术被视为最具潜力的遥感航天器在轨监测技术之一,经过近30年来的研究发展,正在从实验室研究向工程应用演进,但是目前存在若干问题限制了该技术的应用发展,亟待探讨解决方法。为此,梳理了遥感航天器结构微变形监测的主要技术,分析了光纤监测的主要技术类型、技术优缺点、微变形场重建算法、在轨适用性和典型应用案例,指出了需要研究解决的关键问题和未来发展方向。     

Construction of a structural equation model to identify public acceptance factors for hydrogen refueling stations under the provision of risk and safety information

Hydrogen refueling stations (HRSs) are an inevitable infrastructure for the utility of fuel cell vehicles; however, they can raise public safety concerns. The aim of this study is to establish a framework for public acceptance of HRSs in Japan upon the provision of risk and/or safety measure information on HRSs. We executed an in-person interview survey asking the respondents about their acceptance of HRSs and then constructed a structural equation model on HRS acceptance with four endogenous factors. The common factors to determine acceptability were “Dread” and “Independent”. “Balance” was added to the factors for the risk-informed group. If risk information was provided, people tended to judge based on their inherent sense of “Balance”; however, if it was not provided, their judgment was based on their intuitive “Dread” of HRSs or hydrogen. This study reveals risk perception characteristics and attempts to promote improved risk communication prior to HRS installation.     

Practice and prospect of advanced fuel management and fuel technology application in PWR in China

Since Daya Bay nuclear power plant implemented 18-month refueling strategy in 2001, China has completed a series of innovative fuel management and fuel technology projects, including the Ling Ao Advanced Fuel Management (AFM) project (high-burnup quarter core refueling) and the Ningde 18-month refueling project with gadolinium-bearing fuel in initial core. First, this paper gives brief introduction to China's advanced fuel management and fuel technology experience. Second, it introduces practices of the advanced fuel management in China in detail, which mainly focuses on the implementation and progress of the Ningde 18-month refueling project with gadolinium-bearing fuel in initial core. Finally, the paper introduces the practices of advanced fuel technology in China and gives the outlook of the future advanced fuel management and fuel technology in this field.     

基于矢量控制的机场加油系统性能仿真研究

针对机场管道加油系统的要求和特点,建立了矢量控制的变频调速和恒速相结合的三台离心泵并联的机场加油系统。利用AMESim软件,建立了矢量控制三相异步电动机的仿真模型,并与三泵并联的加油系统仿真模型相结合,建立了矢量控制、三泵并联的机场加油系统仿真模型,并进行了性能仿真研究。结果表明:该系统能根据加油枪开启数量的变化自动调节变速泵的转速或恒速泵的启停,以调节系统的供油量,从而保证加油口终端的压力和流量要求,同时加油系统的水击小,节能效果好。     

在轨服务多脉冲远程机动轨道设计与误差分析

针对在轨服务任务对远程机动轨道设计和机动误差展开研究,提出了服务航天器初始停泊轨道的部署原则,采用多脉冲远程机动策略设计了远程机动轨道,在此基础上对如项非球形摄动和大气阻力摄动影响下的服务航天器远程机动轨道进行误差分析,并与双脉冲机动进行了比较,仿真结果表明,在轨服务任务对时间要求不严格时,多脉冲机动优于双脉冲机动,从摄动误差方面考虑调整轨道高度的机动脉冲数为奇数次为宜。     

液态金属反应堆湿式燃料贮存桶内部事件概率安全分析

液态金属冷却剂在给反应堆带来运行安全与热效率优势的同时,也给反应堆带来了复杂的换料系统,其中大型液态金属反应堆采用的湿式乏燃料贮存桶是乏燃料卸料过程的核心设备,临时装载了大量的乏燃料组件,具备一定的安全风险。本文采用概率安全分析（PSA）方法对乏燃料贮存桶进行风险评价,通过运行状态分析、始发事件分析、事故序列分析以及简单的定量化,初步获得其导致乏燃料组件发生损伤的事故序列和最小割集,识别了关键系统与设备。结果表明,相对于反应堆本身的风险,乏燃料贮存桶本身风险虽低但依然不可忽略,且风险评价结果对反应堆的运行方式以及清洗系统的可靠性较为敏感。此外还对该系统的设计改进与安全优化进行了讨论。     

加氢站定量风险分析研究

结合定量风险分析理论和加氢站的特点,从加氢站的事故场景、事故频率、事故后果、死亡概率和个人风险与社会风险5个方面进行了研究,提出了加氢站定量风险分析模型,并结合某加氢站进行了实例计算分析,计算出该加氢站量化的个人风险和社会风险,再与国内外认可的可接受风险标准进行比较,得出其风险水平是否可接受的分析结论。其量化的风险分析结论将对加氢站建设的审批和公众安全认可具有重要指导意义。     

Vehicle refueling with liquid hydrogen thermal compression

We have modeled an approach for dispensing pressurized hydrogen to 350 and/or 700 bar vehicle vessels. Instead of relying on compressors, this concept stores liquid hydrogen in cryogenic pressure vessels where pressurization occurs through heat transfer, reducing the station energy footprint from 12 kW h/kgH₂ of energy from the US grid mix to 1.5–2 kW h/kgH₂ of heating. This thermal compression station presents capital cost and reliability advantages by avoiding the expense and maintenance of high-pressure hydrogen compressors, at the detriment of some evaporative losses. The total installed capital cost for a 475 kg/day thermal compression hydrogen refueling station is estimated at about $611,500, an almost 60% cost reduction over today's refueling station cost. The cost for 700 bar dispensing is $5.23/kg H₂ for a conventional station vs. $5.45/kg H₂ for a thermal compression station. If there is a demand for 350 bar H₂ in addition to 700 bar dispensing, the cost of dispensing from a thermal compression station drops to $4.81/kg H₂, which is similar to the cost of a conventional station that dispenses 350 bar H₂ only. Thermal compression also offers capacity flexibility (wide range of pressure, temperature, and station demand) that makes it appealing for early market applications.