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671.
672.
Optimal robust linearized impulsive rendezvous 总被引:3,自引:1,他引:2
The optimization of time-fixed linearized impulsive rendezvous with control uncertainty is investigated. One performance index related to the variances of the terminal state error is defined as the performance index of robustness which is calculated by linear covariance method. The two-objective optimization problem of minimizing the total characteristic velocity and the performance index of robustness is formulated based on the Clohessy–Wiltshire (C-W) system and solved by the nondominated sorting genetic algorithm. The Pareto-optimal solution sets of one homing rendezvous mission are provided and the Pareto optimality is verified by comparing with the fuel-optimal and the robustness-optimal solutions. It is shown that the proposed approach can quickly investigate the relation between the fuel cost and the trajectory robustness, besides evaluate different rendezvous maneuver schemes. 相似文献
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Barometric altimeter short-term accuracy analysis 总被引:2,自引:0,他引:2
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676.
Identification Method for RLG Random Errors Based on Allan Variance and Equivalent Theorem 总被引:1,自引:0,他引:1
An identification method using Allan variance and equivalent theorem is proposed to identify non-stationary sensor errors mixed out of different simple noises. This method firstly derives the discrete Allan variances of all component noises inherent in noise sources in terms of their different equations; then the variances are used to estimate the parameters of all component noise models; finally, the original errors are represented by the sum of the non-stationary component noise model and the equivalent model mixed out of the stationary and critically stationary component noises. Results of two examples for identification confirm the superiority of this approach regardless of the errors being stationary or not. The comparison of results of real ring laser gyro (RLG) errors processed by various methods shows that the proposed approach is more suited to depict the original noises than common ones. 相似文献
677.
W. Ai S. Guo L. Qin Y. Tang 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008,41(5):742-747
The purpose of the research is to develop a photo-bioreactor which may produce algae protein and oxygen for future astronauts in comparatively long-term exploration, and remove carbon dioxide in a controlled ecological life support system. Based on technical parameters and performance requirements, the project planning, design drafting, and manufacture were conducted. Finally, a demonstration test for producing algae was done. Its productivity for micro-algae and performance of the photo-bioreactor were evaluated. The facility has nine subsystems, including the reactor, the illuminating unit, the carbon dioxide (CO2) production unit and oxygen (O2) generation unit, etc. The demonstration results showed that the facility worked well, and the parameters, such as energy consumption, volume, and productivity for algae, met with the design requirement. The density of algae in the photo-bioreactor increased from 0.174 g (dry weight) L−1 to 4.064 g (dry weight) L−1 after 7 days growth. The principle of providing CO2 in the photo-bioreactor for algae and removing O2 from the culture medium was suitable for the demand of space conditions. The facility has reasonable technical indices, and smooth and dependable performances. 相似文献
678.
春节是我国的传统节日、传统的节日当然有传统的玩法:家庭聚会、逛商场、看灯会……现在,越来越多的年青人正在颠覆这些“传统”。他们利用这难能可贵的大假纵情山水,笑傲江河,在大自然中放逐自我,在异地他乡感受温馨,就像有首歌唱的那样“我要飞得更高,飞得更高,像狂风一样舞蹈……”于他们而言,走出去才是真正的过节。[编按] 相似文献
679.
结合某吹砂机设备中的悬臂吹砂杆的设计过程,探讨了基于Pro/E和AWE软件进行的静力和模态分析。通过对比表明,有限元分析结果与实际使用中的情况非常吻合。这充分说明了CAE技术是设计师的重要实际工具,其分析的数据可以作为设计的参考依据。 相似文献
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集成制造环境下航空转包生产管理 总被引:3,自引:1,他引:2
针对我国航空转包生产的现状,结合多年来航空产品研制与生产的经验,以某飞机制造公司某飞机部件转包生产项目为背景,分析了目前航空转包项目管理的特点和项目管理方法,阐述了在并行工程下航空转包生产项目的复杂性产品研制模式、多层次集成计划与控制体系和项目团队管理过程,并介绍了在并行工程模式下项目管理取得的成效。 相似文献