液体火箭发动机传感器故障检测与数据恢复算法研究

以某型液体火箭发动机为研究对象,根据其传感器的故障特性,提出了基于BP神经网络的传感器故障检测与数据恢复算法。通过定义的传感器置信度来判断传感器是否发生故障,以及确定故障传感器,利用已训练好的神经网络结构对故障传感器进行数据恢复。研究内容能够实现传感器的故障检测、定位与补偿,能够有效提高发动机故障检测方法的可靠性和鲁棒性。     

动态系统慢变型故障的检测与隔离

利用最优奇偶向量法 ,分别设计对执行机构故障和传感器故障敏感的最优奇偶向量 ,产生各自对执行机构故障和传感器故障敏感的残差 ,从而达到将执行机构故障和传感器故障进行分离的目的     

基于神经网络在线建模的非线性动态系统中传感器故障检测方法

本文提出一种基于神经网络在线建模的动态非线性系统中传感器故障检测方法，它首先利用神经网络在线建立动态非线性系统的超前一步预测模型，然后利用神经网络对传感器的预测输出和传感器实际输出之差与一预定阈值比较以检测传感器故障。本文的优点是可以检测多个传感器故障，同时由于采用在线学习方式，非常适于航天器自主系统传感器故障检测的需要。此外，故障检测阈值的选取也比较简单。为了验证本文方法，仿真了一控制系统中同时发生漂移故障的两个传感器故障检测过程。结果表明，方法十分有效。     

面向卫星追踪平台的容错纠错策略与算法研究

针对2RPS+2TPS型卫星追踪平台可能出现的传感器故障提出了一种容错纠错策略。该策略通过在卫星追踪平台的固定平台和动平台中心附加一柔索,柔索一端连接弹簧和冗余传感器,实现了对卫星追踪平台四条驱动腿传感器故障的容错纠错功能。如果驱动腿中的某一个传感器发生故障,则可根据空间闭链机构约束,由其它正常工作驱动腿的传感器和冗余传感器的测量值计算出故障传感器的应测值。推导出了位移和速度传感器故障的容错纠错重构算法。通过模拟渐变型和突变型的传感器故障,对提出的容错纠错方案进行了仿真研究,仿真结果表明提出的容错纠错策略能有效地保障卫星追踪平台系统运行的可靠性和安全性。
     

基于小波分析的容错组合导航系统故障检测算法研究

针对目前多数故障检测法对缓变的软故障检测不灵敏,延迟性较大,无法判断各种故障类别等问题,在分析利用小波奇异性进行故障检测原理的基础上,提出了一种基于模极大值原理的导航传感器故障检测方法。该算法利用传感器的观测量来诊断传感器是否正常工作,文中给出了利用小波奇异性进行故障检测的原理描述及利用该算法进行故障检测算法流程。该算法不仅对导航传感器软故障具有较高的检测灵敏度,而且可以通过故障点处信号的Lipschitz指数来判断故障类别,为传感器故障隔离和修复提供有效的信息,因此可以更好的保障多传感器容错组合导航系统的可靠性。计算机仿真表明所提方法是有效的,具有较高的实用性。     

基于主元分析法的液体火箭发动机传感器故障检测与诊断

针对液体火箭发动机的压力、温度、流量等传感器数据,给出了一种基于主元分析法的传感器故障检测与诊断方法。该方法能够在对测量参数相关性分析的基础上,将传感器测量值所组成的测量空间分解为主元和残差两个子空间,通过传感器实际测量数据与正常数据矩阵在残差子空间投影的比较,对传感器的故障进行检测与诊断。以某型LRE传感器组为研究对象,通过故障模拟,给出了该方法对4种典型传感器故障的检测与诊断实例。结果表明主元分析法对LRE传感器具有很好的故障检测和故障诊断能力。     

考虑传感器故障检测能力的PHM系统传感器优化配置方法

传感器优化配置是航空航天设备PHM系统功能得以有效实现的基础和保证。针对目前传感器配置研究中未考虑传感器实际属性的问题,建立了考虑传感器故障检测能力的PHM系统传感器优化配置模型。首先分析了系统故障-传感器相关性矩阵的含义,将传感器的故障检测能力和相关性矩阵相结合,以概率形式描述了传感器对故障的检测性能。在此基础上根据系统的测试性指标要求建立传感器优化配置模型,并采用混沌二进制粒子群优化算法求解。仿真实例结果表明,本文建立的优化模型更加符合实际情况,配置结果更加准确和可靠。     

卫星动量轮闭环系统的UIO双观测器故障诊断

本文对于卫星动量轮闭环系统提出了一种基于UIO双观测器的故障诊断方法,该方法通过分析观测器残差向量的变化来分离执行机构、传感器及系统参数故障,并且可以通过隔离观测器反映出传感器的故障模式.文中首先对闭环系统故障诊断特点、UIO故障诊断方法及卫星动量轮闭环系统进行了简要介绍;接着分析了UIO双观测器法应用的条件;然后引入卫星动量轮闭环系统的模型;最后通过仿真实验证明利用本文中所提出的方法可以成功地诊断并分离出执行机构、传感器及系统参数的故障,并在传感器故障时可以确定出故障模式.     

基于人工智能方法的传感器故障诊断技术

在液体火箭发动机地面试验过程中,传感器的失效率远高于发动机部件、组件的故障率,因而提出了采用基于人工智能的方法对传感器的故障进行检测与诊断.本文对基于人工智能方法用于传感器故障检测与诊断的特点进行了分析,并分别应用BP神经网络和自适应神经模糊推理系统（ANFIS）对某次传感器的故障进行检测.结果证明基于人工智能的方法稳定可靠,具有良好的工程应用前景.     

航天飞机主发动机的故障探测与隔离

设计了应用于航天飞机主发动机故障探测与隔离(FDI)的广义似然比试验(GLRT),可用于在线 FDI 及飞行任务的事后分析。算法中使用了 SSME 的全部37个状态模型及一套15个传感器。在设计阶段,有助于确定故障的可探测性和可识别性,给出传感器布局。文中重点在于输入/输出的故障,即阀门和传感器失效故障,但似然比方法可延伸至包括结构的失效。     

利用连续推力的人工太阳同步轨道设计方法

针对人工太阳同步轨道的设计方法进行研究,通过施加法向连续推力调整升交点赤经（RAAN）变化率。首次推导了升交点赤经在变方向推力作用下的周期摄动平均值的精确计算公式,解决了已有近似方法对相关轨道参数的取值范围存在限制的问题,并给出了对应的轨道倾角周期摄动平均值计算公式。在分析J2项摄动对升交点赤经影响的基础上,给出了所需的法向连续推力幅值和一个轨道周期内对应的速度增量的计算方法。通过数值仿真,校验了计算公式的正确性,分析了实现人工太阳同步轨道的连续法向推力对轨道倾角的影响,给出了连续推力幅值随轨道参数的变化规律,并且提出了未来工程任务的应用建议。     

微纳卫星星座的Kuhn-Munkres匹配部署优化方法

针对将半长轴、升交点赤经、纬度辐角均不同的低轨微纳卫星群部署到同一轨道面不同目标相位的星座部署问题,提出一种基于Kuhn-Munkres(KM)匹配的星座部署优化方法。通过KM算法实现卫星和目标纬度辐角的优化匹配,充分利用J₂摄动,使升交点赤经借助半长轴和纬度辐角的部署而得到同步修正,从而节约燃料。仿真结果表明,相比于传统部署方法,在相同约束下,优化后的部署方法使各星平均燃耗减少,各星燃耗量均衡性提高。弥补了传统同轨星座部署中将各星初始位置简化为空间一点且忽略部署过程中的升交点赤经漂移的不足。采用有限常值推力实现轨道机动,适用于携带微推力推进系统的微纳卫星。     

Large-size space debris flyby in low earth orbits

the analysis of NORAD catalogue of space objects executed with respect to the overall sizes of upper-stages and last stages of carrier rockets allows the classification of 5 groups of large-size space debris (LSSD). These groups are defined according to the proximity of orbital inclinations of the involved objects. The orbits within a group have various values of deviations in the Right Ascension of the Ascending Node (RAAN). It is proposed to use the RAANs deviations' evolution portrait to clarify the orbital planes’ relative spatial distribution in a group so that the RAAN deviations should be calculated with respect to the concrete precessing orbital plane of the concrete object. In case of the first three groups (inclinations i = 71°, i = 74°, i = 81°) the straight lines of the RAAN relative deviations almost do not intersect each other. So the simple, successive flyby of group’s elements is effective, but the significant value of total ΔV is required to form drift orbits. In case of the fifth group (Sun-synchronous orbits) these straight lines chaotically intersect each other for many times due to the noticeable differences in values of semi-major axes and orbital inclinations. The intersections’ existence makes it possible to create such a flyby sequence for LSSD group when the orbit of one LSSD object simultaneously serves as the drift orbit to attain another LSSD object. This flyby scheme requiring less ΔV was called “diagonal.” The RAANs deviations’ evolution portrait built for the fourth group (to be studied in the paper) contains both types of lines, so the simultaneous combination of diagonal and successive flyby schemes is possible. The value of total ΔV and temporal costs were calculated to cover all the elements of the 4th group. The article is also enriched by the results obtained for the flyby problem solution in case of all the five mentioned LSSD groups. The general recommendations are given concerned with the required reserve of total ΔV and with amount of detachable de-orbiting units onboard the maneuvering platform and onboard the refueling vehicle.     

Solution of the flyby problem for large space debris at sun-synchronous orbits

the paper considers the flyby problem related to large space debris (LSD) objects at low earth orbits. The data on the overall dimensions of known last and upper stages of launch vehicles makes it possible to single out five compact groups of such objects from the NORAD catalog in the 500–2000 km altitude interval. The orbits of objects of each group have approximately the same inclinations. The features of the mutual distribution of the orbital planes of LSD objects in the group are shown in a portrait of the evolution of deviations of the right ascension of ascending nodes (RAAN). In the case of the first three groups (inclinations of 71°, 74°, and 81°), the straight lines of relative RAAN deviations of object orbits barely intersect each other. The fourth (83°) and fifth (97°–100°) LSD groups include a considerable number of objects whose orbits are described by straight lines (diagonals), which intersect other lines many times. The use of diagonals makes it possible to significantly reduce the temporal and total characteristic velocity expenditures required for object flybys, but it complicates determination of the flyby sequence. Diagonal solutions can be obtained using elements of graph theory. A solution to the flyby problem is presented for the case of group 5, formed of LSD objects at sun-synchronous orbits.     

分布式InSAR卫星绕飞角设计与控制方法研究

针对分布式卫星绕飞轨道构型设计与控制问题,提出了基于Hill方程的绕飞构型设计算法,给出了绕飞角与升交点赤经偏差和轨道倾角偏差的关系,并分析了绕飞角的稳定性;根据分布式InSAR卫星绕飞构型特点提出了基于开普勒轨道实现特定绕飞角和绕飞半长轴的双层迭代轨道控制算法。仿真结果表明,上述方法设计的绕飞构型稳定,捕获控制策略简单可行、控制精度高,具有一定的工程参考价值。     

卫星热设计中β角在不同轨道下的变化规律分析

阳光矢量与卫星轨道平面之间夹角是卫星热控设计中至关重要的一个设计参数,其不仅与到达卫星表面的阳光热流密度密切相关,也与到达卫星表面的地球反射热流密度密切相关。文章根据β角的变化规律将传统意义上的轨道分为了同步轨道和非同步轨道两种,并结合升黄赤经夹角的变化规律分析了不同轨道下β角的变化规律,以及相应的热设计特点。     

First results of investigating the space environment onboard the Universitetskii-Tatyana satellite

The complex of scientific pay load installed onboard the research and educational Universitetskii-Tatyana microsatellite of Moscow State University is described. The complex is designed to study charged particles in the near-earth space and ultraviolet emissions of the atmosphere. Data of the measurements of charged particle fluxes in the microsatellite orbit are presented, spectra are calculated, and the dynamics of penetration boundaries for protons of solar cosmic rays (SCR) during geomagnetic disturbances in 2005 is investigated. Intensities of the ultraviolet emission are measured in the entire range of variation of the atmospheric irradiation, as well as intensities of auroras in the polar regions of the Northern and Southern hemispheres. The experimental data on flashes of ultraviolet radiation (transient light phenomena in the upper atmosphere) are considered, and some examples of oscillograms of their temporal development and their distribution over geographical coordinates are presented. Original Russian Text ? V.A. Sadovnichy, M.I. Panasyuk, S.Yu. Bobrovnikov, N.N. Vedenkin, N.A. Vlasova, G.K. Garipov, O.R. Grigorian, T.A. Ivanova, V.V. Kalegaev, P.A. Klimov, A.S. Kovtyukh, S.A. Krasotkin, N.V. Kuznetsov, S.N. Kuznetsov, E.A. Muravyeva, I.N. Myagkova, N.N. Pavlov, R.A. Nymmik, V.L. Petrov, M.V. Podzolko, V.V. Radchenko, S.Ya. Reisman, I.A. Rubinshtein, M.O. Riazantseva, E.A. Sigaeva, E.N. Sosnovets, L.I. Starostin, A.V. Sukhanov, V.I. Tulupov, B.A. Khrenov, V.M. Shakhparonov, V.N. Sheveleva, A.V. Shirokov, I.V. Yashin, V.V. Markelov, N.N. Ivanov, V.N. Blinov, O.Yu. Sedykh, V.P. Pinigin, A.P. Papkov, E.S. Levin, V.M. Samkov, N.N. Ignatiev, V.S. Yamnikol, 2007, published in Kosmicheskie Issledovaniya, 2007, vol. 45, No. 4, pp. 291–305.     

Aquatic modules for bioregenerative life support systems based on the C.E.B.A.S. biotechnology [correction of biotechnilogy

Most concepts for bioregenerative life support systems are based on edible higher land plants which create some problems with growth and seed generation under space conditions. Animal protein production is mostly neglected because of the tremendous waste management problems with tetrapods under reduced weightlessness. Therefore, the "Closed Equilibrated Biological Aquatic System" (C.E.B.A.S.) was developed which represents an artificial aquatic ecosystem containing aquatic organisms which are adapted at all to "near weightlessness conditions" (fishes Xiphophorus helleri, water snails Biomphalaria glabrata, ammonia oxidizing bacteria and the rootless non-gravitropic edible water plant Ceratophyllum demersum). Basically the C.E.B.A.S. consists of 4 subsystems: a ZOOLOGICAL (correction of ZOOLOGICASL) COMPONENT (animal aquarium), a BOTANICAL COMPONENT (aquatic plant bioreactor), a MICROBIAL COMPONENT (bacteria filter) and an ELECTRONICAL COMPONENT (data acquisition and control unit). Superficially, the function principle appears simple: the plants convert light energy into chemical energy via photosynthesis thus producing biomass and oxygen. The animals and microorganisms use the oxygen for respiration and produce the carbon dioxide which is essential for plant photosynthesis. The ammonia ions excreted by the animals are converted by the bacteria to nitrite and then to nitrate ions which serve as a nitrogen source for the plants. Other essential ions derive from biological degradation of animal waste products and dead organic matter. The C.E.B.A.S. exists in 2 basic versions: the original C.E.B.A.S. with a volume of 150 liters and a self-sustaining standing time of more than 13 month and the so-called C.E.B.A.S. MINI MODULE with a volume of about 8.5 liters. In the latter there is no closed food loop by reasons of available space so that animal food has to be provided via an automated feeder. This device was flown already successfully on the STS-89 and STS-90 spaceshuttle missions and the working hypothesis was verified that aquatic organisms are nearly not affected at all by space conditions, i.e. that the plants exhibited biomass production rates identical to the sound controls and that as well the reproductive, and the immune system as the embryonic and ontogenic development of the animals remained undisturbed. Currently the C.E.B.A.S. MINI MODLULE is prepared for a third spaceshuttle flight (STS-107) in spring 2001. Based on the results of the space experiments a series of prototypes of aquatic food production modules for the implementation into BLSS were developed. This paper describes the scientific disposition of the STS-107 experiment and of open and closed aquaculture systems based on another aquatic plant species, the Lemnacean Wolffia arrhiza which is cultured as a vegetable in Southeastern Asia. This plant can be grown in suspension culture and several special bioreactors were developed for this purpose. W. arrhiza reproduces mainly vegetatively by buds but also sexually from time to time and is therefore especially suitable for genetic engineering, too. Therefore it was used, in addition, to optimize the C.E.B.A.S. MINI MODULE to allow experiments with a duration of 4 month in the International Space Station the basic principle of which will be explained. In the context of aquaculture systems for BLSS the continuous replacement of removed fish biomass is an essential demand. Although fish reproduction seems not to be affected in the shortterm space experiments with the C.E.B.A.S. MINI MODULE a functional and reliable hatchery for the production of siblings under reduced weightlessness is connected with some serious problems. Therefore an automated "reproduction module" for the herbivorous fish Tilapia rendalli was developed as a laboratory prototype. It is concluded that aquatic modules of different degrees of complexity can optimize the productivity of BLSS based on higher land plants and that they offer an unique opportunity for the production of animal protein in lunar or planetary bases.     

Novel laboratory approaches to multi-purpose aquatic bioregenerative closed-loop food production systems

Based on the construction principle of the Closed Equilibrated Biological Aquatic System (C.E.B.A.S.) two novel combined animal-plant production systems were developed in laboratory scale the first of which is dedicated to mid-term operation in closed state up to two years. In principle both consist of the "classic" C.E.B.A.S. subcomponents: animal tank (Zoological Component), plant cultivators (Botanical Component), ammonia converting bacteria filter (Microbial Component) and data acquisition/control unit (Electronical Component). The innovative approach in the first system is the utilization of minimally three aquatic plant cultivators for different species. In this one the animal tank has a volume of about 160 liters and is constructed as an "endless-way system" surrounding a central unit containing the heat exchanger and the bacteria filter with volumes of about 1.5 liters each. A suspension plant cultivator (1 liter) for the edible duckweed Wolffia arrhiza is externally connected. The second plant cultivator is a meandric microalgal bioreactor for filamentous green algae. The third plant growth facility is a chamber with about 2.5 liters volume for cultivation of the "traditional" C.E.B.A.S. plant species, the rootless buoyant Ceratophyllum demersum. Both latter units are illuminated with 9 W fluorescent lamps. In the current experiment the animal tank contains the live-bearing teleost fish Xiphophorus helleri and the small pulmonate water snail Biomphalaria glabrata because their physiological adaptation to the closed system conditions is well known from many previous C.E.B.A.S. experiments. The water temperature is maintained at 25 degrees C and the oxygen level is regulated between 4 and 7 mg/l by switching on and off the plant cultivator illuminations according to a suitable pattern thus utilizing solely the oxygen produced by photosynthesis. The animals and the microorganisms of filter and biofilm provide the plants with a sufficient amount of carbon dioxide. Oxygen concentration, pH value, temperature and redox potential are on-line recorded. Ion concentrations and numbers of living germs in the system water are determined twice monthly in the laboratory from samples taken from a special "sample removal module"; the sample volume is automatically replaced from an reservoir container. A rotatory pump produces a water flow of about 38 l/min. For a similar smaller test system with approx. 10 l volume developed from the C.E.B.A.S.-MINI-MODULE a novel indirect solar energy supply is tested which has a buffer capacity to maintain the system for 7 days in darkness under central European climate conditions also in winter. It contains only a single plant cultivator which is operated with Wollfia arrhiza. This lemnacean plant is able to produce large amounts of plant biomass in a short time by vegetative reproduction via daughter fronds. This easy-to-handle apparatus is dedicated to be operative more than 4 month. The experimental animals and microorganisms are the same as in the large system. The paper provides detailed information on the system construction principles and the biological, physical and chemical data of the initial phase of the test runs of both systems with the main focus on the large one.     

Potential evolution of an international moon base programme

The Moon is a major target in expanding human activity in Space. President Bush has called for a Space Exploration Initiative. European participation may depend on achieving an affordable programme and identifying distinct elements for non-U.S. participation. Affordability requires that all participants can influence the “cost to user” of Base operations. If lunar activity is to evolve towards resource exploitation, there will need to be a progressive reduction in operating costs. European interest would prefer participation that allowed longer-term independent interests. The paper addresses how non-U.S. agencies could contribute valuable elements to an International Moon Base while meeting three criteria:

• — Keep a core infrastructure under U.S. control.

• — Avoid a total reliance by the partner on U.S. services.

• — Allow the partner to evolve towards an eventual, semi-autonomous or autonomous capability.

The paper illustrates possible implications of meeting these constraints through “mini infrastructures” combining several elements to form a working architecture. It is concluded that any European participation in an International Moon Base Programme should contain both Space transport and surface elements.