排序方式: 共有138条查询结果,搜索用时 15 毫秒
131.
王波 《西安航空技术高等专科学校学报》2011,29(5):57-60
以AT89C52单片机为核心,完成出租车计价器的设计。采用AT24C02实现在系统掉电时保护,计费显示采用8位8段数码管显示,该设计不仅可以计费,还可以实现白天黑夜的调价,以及中途等待一段时间后总金额的增加,另外设置清零里程按钮用于清零里程和总金额。利用proteus仿真软件模拟出租车计价的功能。 相似文献
132.
In this first part of our paper, it is suggested to use solutions to boundary value problems in the optimization problems (in impulse formulation) for spacecraft trajectories in order to obtain the initial approximation, when boundary value problems of the maximum principle are solved numerically by the shooting method. The technique suggested is applied to the problems of optimal control over motion of the center of mass of a spacecraft controlled by the thrust vector of jet engine with limited thrust in an arbitrary gravitational field in a vacuum. The method is based on a modified (in comparison to the classic scheme) shooting method computation together with the method of continuation along a parameter (maximum reactive acceleration, initial thrust-to-weight ratio, or any other parameter equivalent to them). This technique allows one to obtain the initial approximation with a high precision, and it is applicable to a wide range of optimal control problems solved using the maximum principle, if the impulse formulation makes sense for these problems. 相似文献
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V. K. Saulskiy 《Cosmic Research》2009,47(2):144-155
A new and wider definition is given to multi-satellite systems with linear structure (SLS), and efficiency of their application to multiple continuous coverage of the Earth is substantiated. Owing to this widening, SLS have incorporated already well-recognized “polar systems” by L. Rider and W.S. Adams, “kinematically regular systems” by G.V. Mozhaev, and “delta-systems” by J.G. Walker, as well as “near-polar systems” by Yu.P. Ulybyshev, and some other satellite constellations unknown before. A universal method of SLS optimization is presented, valid for any values of coverage multiplicity and the number of satellites in a system. The method uses the criterion of minimum radius of a circle seen from a satellite on the surface of the globe. Among the best SLS found in this way there are both systems representing the well-known classes mentioned above and new orbit constellations of satellites. 相似文献
135.
A. V. Mordvinov 《Cosmic Research》2008,46(4):314-319
A comparative analysis of variations of the mean solar magnetic field and the interplanetary magnetic field over all history of their measurements is performed. Asymmetry of the solar magnetic field and its manifestation in the heliosphere is investigated. Long-term variations of the solar magnetic field and the heliosphere, which manifest themselves in alternation of dominating magnetic polarities of different sign, are discovered. On the basis of the analysis of cumulative sums of the IMF components, long-term variations of the IMF geometry and of the solar wind spiral angle are found. The cumulative sum of the IMF B z component perpendicular to the ecliptic plane also shows long-term variations. Time intervals are revealed, in which negative values of the IMF B z component dominate, and an increased geomagnetic activity is observed. 相似文献
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G. G. Fedotov 《Cosmic Research》2007,45(2):156-166
An efficient scheme of the use of the Earth’s gravity in interplanetary flights is suggested, which opens up new opportunities for exploration of the solar system. The scheme of the gravitational maneuver allows one to considerably reduce the spacecraft mass consumption for a flight and the time of flight. An algorithm of the gravitational maneuver is suggested that takes into account the restriction on the altitude of a planet flyby. Estimates are made of transport capabilities for delivery of a spacecraft to the orbits of Jupiter, Saturn, and Uranus. The spacecraft is based on a middle-class carrier launcher of the Soyuz type and includes chemical and electric plasma jet engines of the SPD-140 type, which use solar energy. 相似文献
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