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排序方式: 共有197条查询结果,搜索用时 218 毫秒
61.
传统的故障隔离程序采用常规静态故障树进行故障分析,可能会导致故障原因分析不全、故障隔离路径过于繁琐等问题。提出基于系统原理和动态故障树进行故障隔离程序分析的方法,以某飞机防火系统引气导管过热探测系统故障为实例,进行系统设计原理和故障告警逻辑分析,引入动态逻辑门,构建具有顺序相关、功能相关和备份关系的动态故障树;在此基础上进行关联故障分析和排故流程图转化。结果表明:该方法能系统地、全面地反映故障触发逻辑,提供快速、准确、有效的故障隔离程序,提高飞机维修保障水平,在复杂飞机系统的航线维修领域具有良好的应用前景和推广价值。 相似文献
62.
S. Nasir Adeli Vaios J. Lappas Bong Wie 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
Recently, there has been a renewed interest in Solar Sails as an alternative means of space propulsion. Many different attitude control systems have been designed for Solar Sails taking advantage of the centre-of-mass (CM)/centre-of-pressure (CP) offset while utilising the main sail structure to position the actuators. However, by attaching actuators to the main sail, these systems increase the risks involved in the deployment subsystem. 相似文献
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64.
Allan Kardec de ALMEIDA Jr Geraldo Magela Couto OLIVEIRA Antonio Fernando Bertachini de Almeida PRADO 《中国航空学报》2021,34(1):410-423
In the restricted three-body problem, the traditional Lagrange points L1 and L2 are the only equilibrium points near the asteroid 243 Ida. The thrust generated by a solar sail over a spacecraft enables the existence of new artificial equilibrium points, which depend on the position of the spacecraft with respect to the asteroid and the attitude of the solar sail. Such equilibrium points generate new spots to observe the body from above or below the plane of motion. Such points are very good observational locations due to their stationary condition. This work provides a preliminary analysis to observe Ida through the use of artificial equilibrium points as spots combined with transfer maneuvers between them. Such combination can be used to observe the asteroid from more different points of view in comparison to fixed ones. The analyses are made for a spacecraft equipped with a solar sail and capable of performing bi-impulsive maneuvers. The solar radiation pressure is used both to maintain the equilibrium condition and to reduce the costs of the transfers and/or to create transfers with longer duration. This is a new aspect of the present research, because it combines the continuous thrust with initial and final small impulses, which are feasible for most of the spacecraft, because the magnitudes of the impulses are very low. These combined maneuvers may reduce the transfer times of the maneuvers in most of the cases, compared with the maneuvers based only on continuous thrust. Several options involved in these transfers are shown, like to minimize the fuel spent () as a function of the transfer time or to extend the duration of the travel between the points. Extended transfer times can be useful when observations are required during the transfers. 相似文献
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66.
Sudip Bhattacharyya M. Coleman Miller Tod E. Strohmayer Frederick K. Lamb Craig B. Markwardt 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2006,38(12):2765-2767
We discuss millisecond period brightness oscillations and surface atomic spectral lines observed during type I X-ray bursts from a neutron star in a low mass X-ray binary system. We show that modeling of these phenomena can constrain models of the dense cold matter at the cores of neutron stars. We demonstrate that, even for a broad and asymmetric spectral line, the stellar radius-to-mass ratio can be inferred to better than 5%. We also fit our theoretical models to the burst oscillation data of the low mass X-ray binary XTE J1814-338, and find that the 90% confidence lower limit of the neutron star’s dimensionless radius-to-mass ratio is 4.2. 相似文献
67.
评定线轮廓度误差的通用数学模型 总被引:1,自引:0,他引:1
建立了用最小二乘法评定平面曲线轮廓度的通用数学模型。运用该模型可对任意平面曲线的轮廓度进行评定,从而将直线度、圆度、椭圆度以及任何线轮廓度的评定归结在统一的模式中。由于所建立的模型直观、明了,很容易在计算机上实现,因而可在生产实际中普遍推广应用。举例说明了线轮廓度误差可分离成形状误差、参数误差和位姿误差,给出了分离公式和误差补偿原则。 相似文献
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69.
Andrea Caruso Marco Bassetto Giovanni Mengali Alessandro A. Quarta 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2021,67(9):2834-2843
The heliocentric transfer of a solar sail-based spacecraft is usually studied from an optimal perspective, by looking for the control law that minimizes the total flight time. The optimal control problem can be solved either with an indirect approach, whose solution is difficult to obtain due to its sensitivity to an initial guess of the costates, or with a direct method, which requires a good estimate of a feasible (guess) trajectory. This work presents a procedure to generate an approximate optimal trajectory through a finite Fourier series. The minimum time problem is solved using a nonlinear programming solver, in which the optimization parameters are the coefficients of the Fourier series and the positions of the spacecraft along the initial and target orbits. Suitable constraints are enforced on the direction and magnitude of the sail propulsive acceleration vector in order to obtain feasible solutions. A comparison with the numerical results from an indirect approach shows that the proposed method provides a good approximation of the optimal trajectory with a small computational effort. 相似文献
70.
Masanori Matsushita Toshihiro Chujo Jun Matsumoto Osamu Mori Rikio Yokota Hiroyuki Toyota Yasutaka Satou Nobukatsu Okuizumi Hideki Kato Tetsuya Nakamura Yuichi Shibata Tatsuro Nakao Kazuyuki Mori Sanae Fujii Yuki Takao Yuki Kubo Yuya Miyamoto Yuichiro Nada Yudai Kimishima 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2021,67(9):2899-2911
This paper reports on the manufacturing and evaluation of a solar power sail membrane prototype for the OKEANOS project. The in-house prototype was built by the Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency. Mechanical and electrical evaluation tests were conducted. The membrane, thin-film solar cells, reflectivity control devices were good condition after the manufacturing and handling. The improvements in the manufacturing process and design were found. The manufacturing process and design were fundamentally established. After the prototype, improvement plans for the manufacturing process and design were tried. We have a prospect of manufacturing the flight model sail and continue to the development. 相似文献