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61.
环境温度对导弹精度、最大射程的影响分析与修正   总被引:2,自引:0,他引:2  
杨辉耀  鲜勇 《航天控制》2000,18(1):20-25
导弹发射时的环境温度会影响固体发动机的推力,推力的变化一方面影响导弹的精度,另一方面影响导弹的最大射程.根据推力与推进剂初温的关系,建立了计算标准弹道关机点参数偏差的数学模型,计算了这种误差通过制导方程高阶项引起的落点误差,并且对最大射程误差也进行了计算,同时,采用修正制导方程系数的方法,对落点误差进行了修正.仿真结果表明,通过本文提供的方法可以修正环境温度造成的落点偏差.  相似文献   
62.
统计能量分析中几种非共振传输与声场间传输系数研究   总被引:1,自引:0,他引:1  
简述统计能量分析(SEA)中几种非共振传输(近场、直接场、强迫运动)及共振(混响场)传输特性与处理方法,并用简单方法导出声场间一种强迫运动-非共振传输系数表达式,可以满足工程要求。  相似文献   
63.
A large-scale high altitude environment simulation test cabin was developed to accurately control temperatures and pressures encountered at high altitudes. The system was developed to provide slope-tracking dynamic control of the temperature–pressure two-parameter and overcome the control difficulties inherent to a large inertia lag link with a complex control system which is composed of turbine refrigeration device, vacuum device and liquid nitrogen cooling device. The system includes multi-parameter decoupling of the cabin itself to avoid equipment damage of air refrigeration turbine caused by improper operation. Based on analysis of the dynamic characteristics and modeling for variations in temperature, pressure and rotation speed, an intelligent controller was implemented that includes decoupling and fuzzy arithmetic combined with an expert PID controller to control test parameters by decoupling and slope tracking control strategy. The control system employed centralized management in an open industrial ethernet architecture with an industrial computer at the core. The simulation and field debugging and running results show that this method can solve the problems of a poor anti-interference performance typical for a conventional PID and overshooting that can readily damage equipment. The steady-state characteristics meet the system requirements.  相似文献   
64.
火星地表崎岖、环境复杂,火星无人机由于其具有高机动性和灵活性,为火星探测提供了一种新的工作模式,是未来深空探测的重要范式。本文对比了火星与地球相关地表环境参数的差异,分析了火星无人机需要克服的困难和主要用途,阐明了火星无人机实验台的重要性;详细介绍了国内外研究机构研发火星无人机实验台的技术特点与功能优劣,总结了实验台需要具备的模拟火星环境和测量相关参数。在此基础上,提出了构建火星无人机实验台设想,给出了总体设计思想和思路,并对火星无人机气动力学实验平台的应用前景进行了展望。  相似文献   
65.
A way to improve the accuracy of the three-body problem model is taking into account the eccentricity of primary attractors. Elliptic Restricted Three-Body Problem (ER3BP) is a model for studying spacecraft trajectory within the three-body problem such that the orbital eccentricity of primaries is reflected in it. As the principal cause of perturbation in the employed dynamical model, the primaries eccentricity changes the structure of orbits compared to the ideal Circular Restricted Three-Body Problem (CR3BP). It also changes the attitude behavior of a spacecraft revolving along periodic orbits in this regime. In this paper, the coupled orbit-attitude dynamics of a spacecraft in the ER3BP are exploited to find precise periodic solutions as the spacecraft is considered to be in planar orbits around Lagrangian points and Distant Retrograde Orbits (DRO). Periodic solutions are repetitious behaviors in which spacecraft whole dynamics are repeated periodically, these periodic behaviors are the main interest of this study because they are beneficial for future mission designs and allow delineation of the system’s governing dynamics. Previous studies laid the foundation for spacecraft stability analysis or studying pitch motion of spacecraft in the ER3BP regime. While in this paper, at first, initial guesses for correction algorithms were derived through verified search methods, then correction algorithms were used to refine calculated orbit-attitude periodic behaviors. Periodic orbits and full periodic solutions are portrayed and compared to previous studies and simpler models. Natural periodic solutions are valuable information eventuate in the longer functional lifetime of spacecraft. Since the problem assumption considered in this paper is much closer to real mission conditions, these results may be the means to use natural bounded motions in the actual operational environment.  相似文献   
66.
An effective and self-sustainable artificial habitat design is essential for human spaceflight and expansion of mankind into orbit or towards other celestial bodies. There are two approaches that need to be implemented in future sustainable habitats: the use of re-cycling technologies in order to gain experience in closed-loop processes and the primary production of resource materials using In Situ Resource Utilisation (ISRU) principles. Various products will be provided and, where applicable, recycled in such a system taking into account basic human factors requirements such as crew work load capacity, safety and well-being, namely:  相似文献   
67.
能源利用与环境保护   总被引:2,自引:0,他引:2  
能源、环境与发展是人类所关注的永恒主题。论文探讨了中国能源的资源现状和发展前景 ,能源使用对环境的影响以及解决能源与环境问题的途径  相似文献   
68.
对比分析经历模拟特定环境的环境交变试验、盐雾试验、加速老化试验和太阳辐射试验前后泡沫塑料的压缩强度、闭孔率、线胀系数和热导率等性能。结果表明,HCFC-141b型聚氨酯泡沫塑料经历环境老化后,压缩强度和热导率增加,线胀系数减小,闭孔率略有增加,热导率增加。太阳辐照试验对泡沫性能影响最大,试样SD-4压缩强度提高32%,闭孔率先增加后减少,线胀系数降低19%,热导率升高30%。  相似文献   
69.
根据实际使用中出现的问题,对各种实用的管道气流温度传感器的误差进行了计算,对电阻式和热电偶式温度传感器的误差原因作了定量分析。由于带密封罩的温度传感器在实际使用中存在着明显的缺点,建议今后使用热电偶测量飞机环控系统管道气流温度,并提出了一种实用热电偶温度传感器的结构形式,同时也介绍了如何减小由于热传导和热辐射引起的误差。  相似文献   
70.
The launch and successful operation of Chinese–Brazil Earth resources satellite (CBERS-1) in China has accelerated the application of space technology in China. These applications include agriculture, forestry, water conservation, land resources, city planning, environment protection and natural hazards monitoring and so on. The result of these applications provides a scientific basis for government decision making and has created great economic and social benefits in Chinese national economy construction. In this paper we present examples and provide auxiliary documentation of additional applications of the data from Earth resource monitoring.  相似文献   
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