A two-stage approach for managing actuators redundancy and its application to fault tolerant flight control

In safety-critical systems such as transportation aircraft, redundancy of actuators is introduced to improve fault tolerance. How to make the best use of remaining actuators to allow the system to continue achieving a desired operation in the presence of some actuators failures is the main subject of this paper. Considering that many dynamical systems, including flight dynamics of a transportation aircraft, can be expressed as an input affine nonlinear system, a new state representation is adopted here where the output dynamics are related with virtual inputs associated with the intended operation. This representation, as well as the distribution matrix associated with the effectiveness of the remaining operational actuators, allows us to define different levels of fault tolerant governability with respect to actuators’ failures. Then, a two-stage control approach is developed, leading first to the inversion of the output dynamics to get nominal values for the virtual inputs and then to the solution of a linear quadratic(LQ) problem to compute the solicitation of each operational actuator. The proposed approach is applied to the control of a transportation aircraft which performs a stabilized roll maneuver while a partial failure appears. Two fault scenarios are considered and the resulting performance of the proposed approach is displayed and discussed.     

西科斯基进近系统简化近海直升机操作

西科斯基公司推出了一种新型的基于卫星导航的进近系统，简化了直升机传统的海上钻井平台进近时的人工计算和推测，为驾驶员提供了一个自动化的着陆工具，降低了机组成员的工作负荷并增强了态势感知能力。     

A microbial oasis in the hypersaline Atacama subsurface discovered by a life detector chip: implications for the search for life on Mars

The Atacama Desert has long been considered a good Mars analogue for testing instrumentation for planetary exploration, but very few data (if any) have been reported about the geomicrobiology of its salt-rich subsurface. We performed a Mars analogue drilling campaign next to the Salar Grande (Atacama, Chile) in July 2009, and several cores and powder samples from up to 5?m deep were analyzed in situ with LDChip300 (a Life Detector Chip containing 300 antibodies). Here, we show the discovery of a hypersaline subsurface microbial habitat associated with halite-, nitrate-, and perchlorate-containing salts at 2?m deep. LDChip300 detected bacteria, archaea, and other biological material (DNA, exopolysaccharides, some peptides) from the analysis of less than 0.5?g of ground core sample. The results were supported by oligonucleotide microarray hybridization in the field and finally confirmed by molecular phylogenetic analysis and direct visualization of microbial cells bound to halite crystals in the laboratory. Geochemical analyses revealed a habitat with abundant hygroscopic salts like halite (up to 260?g kg(-1)) and perchlorate (41.13?μg g(-1) maximum), which allow deliquescence events at low relative humidity. Thin liquid water films would permit microbes to proliferate by using detected organic acids like acetate (19.14?μg g(-1)) or formate (76.06?μg g(-1)) as electron donors, and sulfate (15875?μg g(-1)), nitrate (13490?μg g(-1)), or perchlorate as acceptors. Our results correlate with the discovery of similar hygroscopic salts and possible deliquescence processes on Mars, and open new search strategies for subsurface martian biota. The performance demonstrated by our LDChip300 validates this technology for planetary exploration, particularly for the search for life on Mars.     

Osmoadaptive strategies of the archaeon Halococcus hamelinensis isolated from a hypersaline stromatolite environment

Biogenic stromatolites are sources of significant information on the evolution of microbial life. Despite their evolutionary significance, little is known about the mechanisms of osmoadaptation by microorganisms that comprise living stromatolites thriving in hypersaline environments. Osmoadaptive strategies for Halococcus hamelinensis, a novel halophilic archaeon recently isolated from living stromatolites in the hypersaline reaches of Shark Bay, were thus a particular interest in this study. To investigate the possibility of "salt-in-cytoplasm"-associated osmoadaptation for this archaeon, flame photometry studies were performed. From the results, it was evident that this halophilic archaeon did not accumulate intracellular K(+) ions when cells were exposed to either osmotic shock or conditions with gradual increments in salinity. These results were further supported by polymerase chain reaction (PCR) analyses where there was no evidence for the existence of homologous genes to an ATP-driven, high-affinity potassium uptake system in Halococcus hamelinensis. To identify an alternative salt adaptation mechanism associated with accumulation of compatible solutes for this archaeon, (1)H nuclear magnetic resonance (NMR) spectroscopy experiments were carried out. Results indicate that glycine betaine, trehalose, and glutamate are solutes likely to be involved in osmoregulation in this archeaon. Subsequent (1)H NMR analysis of cell extracts from this microorganism grown under various NaCl concentrations revealed that intracellular levels of glycine betaine increased with increasing concentrations of NaCl. This behavior of increasing glycine betaine concentration with increasing external NaCl is consistent with its identity as an osmolyte. In contrast, intracellular levels of trehalose were decreased in high concentrations of NaCl. This provides evidence that compatible solute accumulation appears to be the preferential salt regulation mechanism for this haloarchaeon, in contrast to the salt-in-cytoplasm strategy employed by many other halophilic archaea.     

三天线SAR干涉仪系统的模拟模型和性能分析

为了减小常规ＳＡＲ干涉仪技术相位模糊和噪声的不利因素，最近提出用于三维地形测绘的采用最佳统计数据处理的一种三天线ＳＡＲ干涉仪。本文提出一种统计模型以在仿真现场模糊新系统的大部分工作条件。     

迎角指示器市场转旺

DepotStar是一家小型公司，以保障迎角安全的创新设计打开了轻型飞机市场。     

EMC应用中数字集成电路宏模的研究

本文描述了对数字电路进行宏模的方法,进而构造了数字电路在静态和动态两种情况下输入特性和输出特性的网络模型。模型结构由简单的网络单元构成,例如电压控制的电流源和非线性电容。最后,对网络模型的未知参数的产生方法也进行了描述。     

孔、轮廓和表面(十三) 第八章 座标磨削的原理和应用(二)

动力头的往复运动——让支架和连接组件通过机械传动来实现往复移位运动,看来是不切实际的。这在很大程度上是由于需要在每分钟内作0～120次的无级调速往复运动,     

汤姆逊-CSF公司寻求更大的市场

像其他许多法国防务设备制造商一样,汤姆逊-CSF公司的电子系统分公司(ESD)在许多对外销售市场中(特别对中东)一直是相当成功的.但近年由于石油价格下跌,已经导致中东及其他地区一些国家不得不削减、甚至中断他们的主要防御合同.因此,目前该公司正在积极使其硬件和软件产品进入竞争激烈的美国市场.