7000米载人潜水器推进器故障容错控制分配研究

介绍了7000米载人潜水器推进系统的组成和推进器布置,描述了潜水器控制分配问题,对推进器推力和期望控制量进行了归一化处理.根据载人潜水器的推进器布置,建立了系统的控制分配模型,设计了推进器故障容错处理策略,研究了基于推力最小二范数的载人潜水器控制分配求解方法.采用基于伪逆矩阵与定点分配的混合控制分配求解算法,在半物理仿真平台上实验验证了控制分配求解算法的正确性和有效性.

7000米载人潜水器动力定位系统研究

深海载人潜水器可以运载科学家和工程技术人员，以及各种仪器设备进入深海现场，进行各种海洋资源调查、科学考察和海底调查等作业任务。近十五年来，深海载人潜水器为促进海洋资源调查、海洋生物基因、海洋地质勘探等与海洋相关研究领域的发展作出了显著贡献。未来，深海载人潜水器还将在与海洋相关研究领域，以及海洋资源开发与争夺过程中发挥更加重要的作用。随着海洋高技术的发展，人类对海洋的研究更加深入和精细，在众多作业任务中，将逐渐要求深海载人潜水器具有动力定位能力。精确的动力定位能力，可以有效提高载人潜水器的作业能力和效率，降低操作人员的作业强度。影响深海载人潜水器动力定位系统性能的因素有很多，主要包括状态感知系统的测量精度、作业系统作业过程中产生的扰动、复杂海洋环境产生的复杂外力干扰、以及推进子系统的控制分配和故障容错能力等。 本文以“十五”期间国家863计划重大专项“7000米载人潜水器”为研究背景，结合7000米载人潜水器动力定位能力的实际应用需求，深入研究了7000米载人潜水器动力定位系统，实现高精度、高稳定性的动力定位。重点研究能有效提高7000米载人潜水器水平位置和线速度测量精度的导航方法；研究适合存在复杂外界干扰和自身不确定性条件下，多输入多输出的载人潜水器智能控制方法；研究具有推进器故障容错能力的动态控制分配策略。本文研究内容主要包括： （1） 根据7000米载人潜水器的传感器配置情况，研究基于多普勒速度计程仪和光纤罗经的载人潜水器导航问题。提出基于“当前”加速度统计模型和潜水器运动方程的Kalman Filter导航方法，这种导航方法可以在线准确地估计出多普勒速度计程仪的速度测量偏差比例因子，以及多普勒速度计程仪和光纤罗经间的航向角安装偏差。通过仿真实验和湖上试验数据验证实验，验证了该导航方法的正确性和有效性。 （2） 基于潜水器6自由度空间动力学模型，设计了基于径向基神经网络直接自适应控制策略的7000米载人潜水器动力定位控制器。基于Lyapunov稳定性理论，证明了存在有界外界干扰和有界神经网络逼近误差条件下，7000米载人潜水器控制系统的闭环稳定性。通过7000米载人潜水器动力学模型的仿真实验和水下机器人实验平台的水池实验，进一步验证了该控制系统的正确性、有效性和稳定性。 （3） 提出了采用动态模糊神经网络在线学习算法，解决基于径向基神经网络载人潜水器直接自适应控制方法的网络结构设计困难问题。改进了用于机械手运动控制的动态模糊神经网络在线学习算法的结构学习部分，使其更适用于载人潜水器的控制。基于Lyapunov稳定性理论，证明了基于动态模糊神经网络直接自适应控制策略的载人潜水器控制系统的闭环稳定性，并进行了仿真实验。 （4） 基于推进器配置情况，建立了7000米载人潜水器的动态控制分配模型，设计了推进器故障容错处理策略。针对完全固定推进器配置的潜水器系统，提出了基于伪逆矩阵分配和定点分配策略相结合的混合动态控制分配算法。针对存在可动态配置的回转推进器，提出基于SQP算法的动态非线性优化控制分配策略，设计了优化算法的代价函数。通过仿真实验和7000米载人潜水器半物理仿真平台实验，验证了本文研究的潜水器动态控制分配算法的正确性和有效性。

A 7000 yr perspective on volcanic ash clouds affecting northern Europe

The ash cloud resulting from the 2010 eruption of Eyjafjöll caused severe disruption to air travel across Europe but as a geological event, it is not unprecedented. Analysis of peat and lake sediments from northern Europe has revealed the presence of microscopic layers of Icelandic volcanic ash (tephra). These sedimentary records, together with historical records of Holocene ash falls, demonstrate that Icelandic volcanoes have generated substantial ash clouds that reached northern Europe many times. Here we present the first comprehensive compilation of sedimentary and historical records of ash-fall events in northern Europe, spanning the last 7000 years. Within this period ten tephra layers have been identified in the Faroe Islands, 14 in Great Britain, 11 in Germany, 38 in Scandinavia and 33 in Ireland. Seven ash fall events have been historically documented prior to the Eyjafjöll 2010 event. Ash fall events appear to be more frequent in the last 1500 years, but it is unclear whether this reflects a true increase in eruption frequency or dispersal, or is an artefact of the records themselves or the way they have been generated. In the last 1,000 years, volcanic ash clouds reached Northern Europe with a mean return interval of 53 ± 8 years (the range of return intervals is between 6 and 112 years). Modelling using the ash records for the last millennium indicates that for any 10 year period there is a 17% probability of tephra fallout event in Northern Europe. These values must be considered as conservative estimates due to the nature of tephra capture and preservation in the sedimentary record.

Atmospheric chemistry of C4F9OC2H5 (HFE-7200), C4F9OCH3 (HFE-7100), C3F7OCH3 (HFE-7000) and C3F7CH2OH: temperature dependence of the kinetics of their reactions with OH radicals, atmospheric lifetimes and global warming potentials

The atmospheric chemistry of several gases used in industrial applications, C4F9OC2H5 (HFE-7200), C4F9OCH3 (HFE-7100), C3F7OCH3 (HFE-7000) and C3F7CH2OH, has been studied. The discharge flow technique coupled with mass-spectrometric detection has been used to study the kinetics of their reactions with OH radicals as a function of temperature. The infrared spectra of the compounds have also been measured. The following Arrhenius expressions for the reactions were determined (in units of cm3 molecule-1 s-1): k(OH + HFE-7200) = (6.9+2.3-1.7) × 10-11 exp(-(2030 ± 190)/T); k(OH + HFE-7100) = (2.8+3.2-1.5) × 10-11 exp(-(2200 ± 490)/T); k(OH + HFE-7000) = (2.0+1.2-0.7) × 10-11 exp(-(2130 ± 290)/T); and k(OH + C3F7CH2OH) = (1.4+0.3-0.2) × 10-11 exp(-(1460 ± 120)/T). From the infrared spectra, radiative forcing efficiencies were determined and compared with earlier estimates in the literature. These were combined with the kinetic data to estimate 100-year time horizon global warming potentials relative to CO2 of 69, 337, 499 and 36 for HFE-7200, HFE-7100, HFE-7000 and CF3CF2CF2CH2OH, respectively.

Prediction of hip fracture risk by quantitative ultrasound in more than 7000 Swiss women > or =70 years of age: comparison of three technologically different bone ultrasound devices in the SEMOF study

To compare the prediction of hip fracture risk of several bone ultrasounds (QUS), 7062 Swiss women > or =70 years of age were measured with three QUSs (two of the heel, one of the phalanges). Heel QUSs were both predictive of hip fracture risk, whereas the phalanges QUS was not. INTRODUCTION: As the number of hip fracture is expected to increase during these next decades, it is important to develop strategies to detect subjects at risk. Quantitative bone ultrasound (QUS), an ionizing radiation-free method, which is transportable, could be interesting for this purpose. MATERIALS AND METHODS: The Swiss Evaluation of the Methods of Measurement of Osteoporotic Fracture Risk (SEMOF) study is a multicenter cohort study, which compared three QUSs for the assessment of hip fracture risk in a sample of 7609 elderly ambulatory women > or =70 years of age. Two QUSs measured the heel (Achilles+; GE-Lunar and Sahara; Hologic), and one measured the heel (DBM Sonic 1200; IGEA). The Cox proportional hazards regression was used to estimate the hazard of the first hip fracture, adjusted for age, BMI, and center, and the area under the ROC curves were calculated to compare the devices and their parameters. RESULTS: From the 7609 women who were included in the study, 7062 women 75.2 +/- 3.1 (SD) years of age were prospectively followed for 2.9 +/- 0.8 years. Eighty women reported a hip fracture. A decrease by 1 SD of the QUS variables corresponded to an increase of the hip fracture risk from 2.3 (95% CI, 1.7, 3.1) to 2.6 (95% CI, 1.9, 3.4) for the three variables of Achilles+ and from 2.2 (95% CI, 1.7, 3.0) to 2.4 (95% CI, 1.8, 3.2) for the three variables of Sahara. Risk gradients did not differ significantly among the variables of the two heel QUS devices. On the other hand, the phalanges QUS (DBM Sonic 1200) was not predictive of hip fracture risk, with an adjusted hazard risk of 1.2 (95% CI, 0.9, 1.5), even after reanalysis of the digitalized data and using different cut-off levels (1700 or 1570 m/s). CONCLUSIONS: In this elderly women population, heel QUS devices were both predictive of hip fracture risk, whereas the phalanges QUS device was not.

7000-year human legacy of elevation-dependent European fire regimes

Variability in fire regime at the continental scale has primarily been attributed to climate change, often overshadowing the widely potential impact of human activities. However, human ignition modifies the rhythm of fire episodes occurrence (fire frequency), whereas land use alters vegetation composition and fuel load, and thus the amount of biomass burned. It is unclear, however, whether and how humans have exercised a significant influence over fire regimes at continental and millennial scales. Based on sedimentary charcoal records, we use new alternative estimate of fire frequency and biomass burned for the last 16000 years (here after 16 ky) that we evaluate with outputs from climate, vegetation, land use and population models. We find that pronounced regional-scale land use changes in southern Europe at the beginning of the Neolithic (8–6 ky), during the Bronze Age (5–4 ky) and the medieval period (1 ky) caused a doubling of fire frequency compared to the Holocene average (the last 11.5 ky). Despite anthropogenic influences, southern European biomass burned decreased from 7 ky, which is in line both with changes in orbital parameters leading climate cooling and also reductions in biomass availability because of land use. Our study underscores the role of elevation-dependent parameters, and particularly biomass and land management, as major drivers of fire regime variability. Results attest a determinant anthropogenic driving-force on fire regime and a decrease in fire-carbon emissions since 7 ky in Southern Europe.

Buque oceanográfico de 7000 toneladas de desplazamiento

Diseño de anteproyecto de un buque oceanográfico de 7000 toneladas de desplazamiento

Imports into the United States for consumption, by countries, for the calendar year 1936. W. P. A. statistical project 265-31-7000, Richmond, Virginia ...

"Compiled from preliminary statistics of imports supplied by the Department of commerce."

Plan of 59 different tracts of land (of 1000 acres each) containing in the whole 59,000 acres : situate on different waters of south Edisto River, except seven tracts (or 7000 acres) are lying on the waters of north Edisto River in the District of Orangeburgh, State of South Carolina /

Pen-and-ink and watercolor.

Manual pedagógico de queratometría y refracción convencional y computarizada (equipo huvitz hrk 7000)

Tesis (Optometra). -- Universidad de La Salle, Facultad de Ciencias de La Salud. Programa de Optometria, 2015

An application of near-infrared and mid-infrared spectroscopy to the study of natural halotrichites : halotrichite, apjohnite and wupatkiite

Near-infrared (NIR) and Fourier transform infrared (FTIR) spectroscopy have been used to determine the mineralogical character of isomorphic substitutions for Mg2+ by divalent transition metals Fe, Mn, Co and Ni in natural halotrichite series. The minerals are characterised by d-d transitions in NIR region 12000-7500 cm-1. NIR spectrum of halotrichite reveals broad feature from 12000 to 7500 cm-1 with a splitting of two bands resulting from ferrous ion transition 5T2g ® 5Eg. The presence of overtones of OH- fundamentals near 7000 cm-1 confirms molecular water in the mineral structure of the halotrichite series. The appearance of the most intense peak at around 5132 cm-1 is a common feature in the three minerals and is derived from combination of OH- vibrations of water molecules and 2 water bending modes. The influence of cations like Mg2+, Fe2+, Mn2+, Co2+, Ni2+ shows on the spectra of halotrichites. Especially wupatkiite-OH stretching vibrations in which bands are distorted conspicuously to low wave numbers at 3270, 2904 and 2454 cm-1. The observation of high frequency 2 mode in the infrared spectrum at 1640 cm-1 indicates coordination of water molecules is strongly hydrogen bonded in natural halotrichites. The splittings of bands in 3 and 4 (SO4)2- stretching regions may be attributed to the reduction of symmetry from Td to C2v for sulphate ion. This work has shown the usefulness of NIR spectroscopy for the rapid identification and classification of the halotrichite minerals.

Comparison of intranasal and transcutaneous immunization for induction of protective immunity against chlamydia muridarum respiratory tract infection

Chlamydia pneumoniae causes a range of respiratory infections including bronchitis, pharyngitis and pneumonia. Infection has also been implicated in exacerbation/initiation of asthma and chronic obstructive pulmonary disease (COPD) and may play a role in atherosclerosis and Alzheimer's disease. We have used a mouse model of Chlamydia respiratory infection to determine the effectiveness of intranasal (IN) and transcutaneous immunization (TCI) to prevent Chlamydia lung infection. Female BALB/c mice were immunized with chlamydial major outer membrane protein (MOMP) mixed with cholera toxin and CpG oligodeoxynucleotide adjuvants by either the IN or TCI routes. Serum and bronchoalveolar lavage (BAL) were collected for antibody analysis. Mononuclear cells from lung-draining lymph nodes were stimulated in vitro with MOMP and cytokine mRNA production determined by real time PCR. Animals were challenged with live Chlamydia and weighed daily following challenge. At day 10 (the peak of infection) animals were sacrificed and the numbers of recoverable Chlamydia in lungs determined by real time PCR. MOMP-specific antibody-secreting cells in lung tissues were also determined at day 10 post-infection. Both IN and TCI protected animals against weight loss compared to non-immunized controls with both immunized groups gaining weight by day 10-post challenge while controls had lost 6% of body weight. Both immunization protocols induced MOMP-specific IgG in serum and BAL while only IN immunization induced MOMP-specific IgA in BAL. Both immunization routes resulted in high numbers of MOMP-specific antibody-secreting cells in lung tissues (IN > TCI). Following in vitro re-stimulation of lung-draining lymph node cells with MOMP; IFNγ mRNA increased 20-fold in cells from IN immunized animals (compared to non-immunized controls) while IFNγ levels increased 6- to 7-fold in TCI animals. Ten days post challenge non-immunized animals had >7000 IFU in their lungs, IN immunized animals <50 IFU and TCI immunized animals <1500 IFU. Thus, both intranasal and transcutaneous immunization protected mice against respiratory challenge with Chlamydia. The best protection was obtained following IN immunization and correlated with IFNγ production by mononuclear cells in lung-draining LN and MOMP-specific IgA in BAL.

Design optimisation of ironless motors based on magnet selection

This paper considers the design of a radial flux permanent magnet iron less core brushless DC motor for use in an electric wheel drive with an integrated epicyclic gear reduction. The motor has been designed for a continuous output torque of 30 Nm and peak rating of 60 Nm with a maximum operating speed of 7000 RPM. In the design of brushless DC motors with a toothed iron stator the peak air-gap magnetic flux density is typically chosen to be close to that of the remanence value of the magnets used. This paper demonstrates that for an ironless motor the optimal peak air-gap flux density is closer to the maximum energy product of the magnets used. The use of a radial flux topology allows for high frequency operation and can be shown to give high specific power output while maintaining a relatively low magnet mass. Two-dimensional finite element analysis is used to predict the air-gap flux density. The motor design is based around commonly available NdFeB bar magnet size

Design optimisation of ironless motors based on magnet selection

This paper considers the design of a radial flux permanent magnet ironless core brushless DC motor for use in an electric wheel drive with an integrated epicyclic gear reduction. The motor has been designed for a continuous output torque of 30 Nm and peak rating of 60 Nm with a maximum operating speed of 7000 RPM. In the design of brushless DC motors with a toothed iron stator the peak air-gap magnetic flux density is typically chosen to be close to that of the remanence value of the magnets used. This paper demonstrates that for an ironless motor the optimal peak air-gap flux density is closer to the maximum energy product of the magnets used. The use of a radial flux topology allows for high frequency operation and can be shown to give high specific power output while maintaining a relatively low magnet mass. Two-dimensional finite element analysis is used to predict the airgap flux density. The motor design is based around commonly available NdFeB bar magnet size