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针对飞机高原着陆释放阻力伞气动力增大机理与控制方法开展了研究与验证。首先,分析了阻力伞高/平原开伞动载情况。然后,对阻力伞高/平原拉直力进行了研究,理论推导出开伞过程中拉直力随海拔高度增加而增大;通过试验现象研究指出采用先拉伞衣法,拉直过程中主伞衣不加约束控制的随机充气,在提前充气阻力特征达到一定条件下,拉直力的数值会超过开伞动载,并分别在平原地区进行了调研取证和高原地区专项试验验证。最后,针对高原试验中阻力伞轴颈断裂问题,提出了加装伞衣套约束主伞衣提前充气控制拉直力增大的方法,并进行了试验验证。研究成果表明,对阻力伞高原开伞过程气动力增大机理与控制方法的研究及验证的结果是一致的,措施是有效的。 相似文献
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针对某型飞机阻力伞系统放伞、抛伞故障,通过分析系统的组成、工作原理、常见故障模式以及故障原因,提出了改进建议,为该型飞机阻力伞抛放系统故障的排除提供思路。 相似文献
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模型自由飞投放试验主要用于获得飞机失速/偏离、初始尾旋到发展尾旋动态特性,以及改出方法。回收段是模型自由飞投放试验最易出故障,且后果最严重的阶段。文中分析了伞降系统组成及工作过程,对伞结构形式、伞面积、伞舱位置、开伞速度和过载等关键参数确定方法,进行了研究,此外,结合模型自由飞投放试验特点设计了多余度的开伞控制系统。试飞结果表明,该系统集成度高、可靠性高,能够大大提高开伞成功率,适合在后续模型自由飞投放试验中推广使用。 相似文献
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利用风洞试验研究冲压翼伞的升阻特性 总被引:1,自引:0,他引:1
冲压翼伞的风洞试验是研制冲压翼伞过程中的一项重要内容。介绍了投物用冲压翼伞风洞试验的特点及发展,着重讨论了这类冲压翼伞的升阻特性,通过理论计算与试验结果的比较,分析了柔翼与刚性翼之间的差异,得出了升阻比最佳点,同时,还分析了冲压翼伞各部分阻力的构成情况,提出了减少阻力的主要措施。 相似文献
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前缘切口以及后缘下偏是影响伞衣气动力计算的关键因素。为实现伞翼无人机(UAV)的精确控制,从提高翼伞系统动力学模型的精度入手,在升力线理论的基础上,基于计算流体动力学方法,综合考虑前缘切口以及后缘下偏的影响,计算了不同切口尺寸模型的升力、阻力系数。利用最小二乘法辨识了升力、阻力系数与迎角、切口尺寸以及下偏量的关系,实现了翼伞气动力的精确计算,改进了伞翼无人机的六自由度动力学模型。对改进的动力学模型进行轨迹跟踪控制的仿真,通过与空投试验数据的对比,验证了改进翼伞系统动力学模型方法的准确性,对于伞翼无人机的仿真和控制器设计具有重要意义。 相似文献
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本文介绍的动力长降伞的研制是在充分的气动、飞行、强度试验基础上,进行精心的总体设计和另构件及系统设计。以满足和达到人机飞行器的设计性能指标。 相似文献
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差值法与比值法对不同测量系统的误差修正效果不一样。本文将两种方法的比较用一个比值来描述,并用推得的公式进行量化表示。在进一步的应用研究中,理论分析与实验数据相互印证,同时得到许多有益的结论,有助于全面掌握测量系统的误差来源,从而灵活选择各种修正方法以获得更加准确的测量结果。 相似文献
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李稷 《民用飞机设计与研究》2010,(4):33-36,41
飞控系统主作动器电子控制装置(P-ACE)是现代电传飞控系统的核心部件。飞控系统主作动器电子控制装置仿真器采用数字仿真模块扩展模拟电路接口的仿真技术,具有与真件功能相似、接口相同的特性,可以代替飞控系统主作动器电子控制装置真件,参与飞控系统的调试和试验,对研究飞控系统的功能和性能具有重要意义。 相似文献
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In this paper, we consider the concept of the impact of an action or human error. We begin from an informal definition of impact as: the effect that an action or sequence of actions has on the safe and successful operation of a system; and develop a quantitative measure of the impact of specified behaviours. It is important that human-machine interface designers should understand the relationship between operator actions and the hazards associated with a system. We demonstrate how impact can be assessed prior to, or in parallel with, the design of the human-machine interface, and show how impact assessments could be used to allow risk analysts to inform designers about the relationship between operator actions and system hazards. To illustrate our approach we present a simple case study, 相似文献
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Donald D. Clayton 《Space Science Reviews》1979,24(2):147-226
This review concentrates on recent ideas involving a relationship between the early solar system and supernova explosions. It summarizes briefly the data that has helped inspire those ideas. Because the true relationship is still unknown and generates controversy, the distinct ideas are introduced singly in the historical context of their origins, and the active sense of surprise and controversy is visible. Quotations from pivotal papers are used as part of the exposition. The subject involves equally the isotopic anomalies detected in meteorites and the dynamic events of galactic evolution, nucleosynthesis, and protosolar collapse. Whatever the correct situation is, new connections have been found between the origin of the elements and the formation of the solar system. The objective of this review is to enable interested space scientists to quickly identify the competing points of view and the experiments and theories that have led to them. 相似文献
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Now extinct short-lived radioactive isotopes were apparently extant in the early solar system. Their abundances can be inferred
from isotopic effects in their daughter nuclei in primitive meteorites, and the deviation of these abundances from expectations
from continuous galactic nucleosynthesis yields important information on the last nucleosynthetic events that contributed
new nuclei to the solar system and on the general circumstances of the Sun's birth. In this paper we present a rudimentary
model that attempts to reconcile the abundances of ten short-lived radioactivities in the early solar system. In broad outlines,
the picture requires 1) that Type Ia supernovae maintained a steady ISM supply of 53Mn and 146Sm, 2) that the r-process events that slowly admixed new 107Pd, 129I, 182Hf, and 244Pu nuclei to the solar system occurred over an interval of several hundred million years prior to solar system formation,
and 3) that a massive star, by injecting only material outside its helium-exhausted core into the proto-solar nebula, contributed
26Al, 36Cl, 41Ca, 60Fe, and 182Hf no more than one million years prior to the Sun's birth. In this picture, the live 182Hf present in the early solar system was not due to r-process production but rather to a fast s-process in helium or carbon
burning shell in the massive star. We conclude with a possible chemical-memory explanation for the putative 53Cr/52Cr gradient in the solar system.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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K. B. Panfilovich 《Russian Aeronautics (Iz VUZ)》2014,57(1):71-74
In this paper, a physical model of gas flows through the channels is refined. The influence of gas absorbed by the walls of a channel on its conductance is shown. The experimentally obtained minimum on the channel conductance-pressure dependence (as the Knudsen paradox) is interpreted. 相似文献
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This paper summarizes some of the discussions of working group 8–9 during the ISSI Conference on The Heliosphere in the Local Interstellar Medium. Because the subject of these working groups has become significantly broader during the last ten years, we have selected three topics for which recent observations have modified and improved our knowledge of the heliosphere and the surrounding interstellar medium. These topics are the number densities and ISM ionization states of hydrogen and helium, the newly discovered hot gas from the H wall seen in absorption, and the comparison between ISM and heliospheric minor element abundances. Papers from this volume in which more details on these topics can be found are quoted throughout the report. 相似文献