共查询到20条相似文献，搜索用时 78 毫秒
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《天文研究与技术》2020,(2)
观测技术及仪器的进步推动了太阳物理的研究,步进电机是各类观测仪器精密结构调整部件中经常采用的驱动源,步进电机控制系统的性能直接影响太阳望远镜的数据精度和时间分辨率。介绍了一套怀柔太阳观测基地自主研制的多轴步进电机控制系统。该系统以现场可编程门阵列为核心控制器,利用中断处理机制及输入/输出寄存器产生多路晶体管-晶体管逻辑电平(TTL)方波信号,结合驱动器实现多轴步进电机控制;通过周期信号化简处理算法缩短电机调整时间;以霍尔器件作为位置传感器实现系统闭环控制,通过对霍尔信号的软、硬件滤波处理,提高信号识别的准确率;设计了板载存储电路,实时保存系统关键参数,大幅提高系统整体的可靠性。同时,该系统设计了丰富的输入/输出接口、通讯接口,提高系统的可集成性。目前该系统已在多台太阳望远镜中投入使用。 相似文献
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讨论了如何将SOPC技术用于大天区多目标光纤光谱天文望远镜(LAMOST)项目的低分辨率光谱仪IP控制核的设计,并在NIOSⅡ软核基础上设计实现了光谱仪IP控制核。整个IP控制核主要分为底层电机控制单元和通信单元两部分。通过工业以太网,远程控制计算机可以方便地控制低分辨率光谱仪,使其完成指定动作。也可以从本地控制计算机上实行控制。设计中采用将步进电机控制器封装成IP再复用的方法,大大缩短了研发时间,减少错误的发生。通信控制中串口通信和以太网可以互为冗余,保证了通信的顺利进行。 相似文献
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从低频导航系统的工作原理分析,主副台的同步精度直接影响着导航精度。传统采用的主副台主从同步工作方式不可避免地要引入主副台间电波传播时延起伏导致的副台同步误差,进而会对导航精度产生影响。后来采用的被称为“自由同步”的主副台同步方式,副台发射时延作为一个常数由固定监测站通过对台对的时间差测量实施监测控制。这在原理上摆脱了副台测收跟综主台的电波传播不稳定因素的影响,但又较大程度地依赖台对至监 相似文献
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介绍了北京天文台 60 0 / 90 0mm施密特望远镜驱动系统的改进设计 ,即用 2只步进电机 ,取代了原望远镜由 4只变速箱、 7只电机驱动的复杂的赤经 ,赤纬驱动系统 ,最终实现了计算机控制。 相似文献
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介绍了北京天文台６００／９００ｍｍ施密特望远镜驱动系统的改进设计,即用２只步进电机,取代了原望远镜由４只变速箱、７只电机驱动的复杂的赤经,赤续驱动系统,最终实现了计算机控制。 相似文献
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V. Batllo 《Celestial Mechanics and Dynamical Astronomy》1998,71(3):191-201
The objective of this paper is to develop a simple model of an encounter between a comet and a planet, with a subsequent capture
or an escape, and to study the potential consequences. The hypothetical scenario is as follows: a comet with a conic orbit
meets close to one of its vertices (located near the ecliptic plane), a jovian planet, and transforms its orbit. There are
two hypotheses which are made for the shock: this vertex becomes one of the final vertices and the orbital plane of the comet
is unchanged during the encounter as it was the case for Brooks 2 in 1886.
In this model, it was able to find an equation which was then used to obtain the pre‐ and post‐encounter orbits elements and
the kind of orbit (ellipse, hyperbola, parabola) with respect to the initial inclination. The numerical experiments with the
observed comets often provide pre‐encounter orbits with an aphelion point located near another jovian planet farther from
the Sun, and so on with sometimes several planets, or with an aphelion point located beyond the Pluto orbit.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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We formulate the problem of an infinitesimal particle moving in the space under the influence of the gravitational force induced
by a homogeneous annulus disk fixed on a plane. We compute using different coordinates and in terms of an elliptic integral
the potential associated to this problem. Also we study the symmetries of the associated potential. After that, we look at
the dynamics in some particular cases, namely: in the line perpendicular to the plane that contains the annulus disk and passes
through the center of the ring and on the plane that contains the massive annulus.
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Results of evolutionary calculations for a close binary system with a central helium burning He-star filling its Roche lobe and an accreting white dwarf are presented. Values for the mass of the components and the degree of central helium exhaustion before the filling of the Roche lobe are varied. It is shown that in such a system the mass accretion rate will remain for a long time (2–4) Ö 10–8
yr–1 ifq<1 (q=M
He,2/M
CO,1). The obtained results are discussed in connection with pre-supernova I phenomenon. 相似文献
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Tapan K. Chatterjee 《Astrophysics and Space Science》1981,76(2):491-502
The tidal force effects of a spherical galaxy passing head-on through a disk galaxy have been studied at various regions of the disk galaxy and for various orientations of the disk galaxy with respect to the direction of relative motion of the two galaxies. The density distribution of the disk galaxy is taken to be, (r)=ce–4r/R
, where c is the central density andR is the radius of the disk. The density distribution of the spherical galaxy is taken to be that of a oolytrope of indexn=4. It is found that as a result of the collision, through the central parts and the outer parts of the disk galaxy remain intact, the region in between these two regions disrupts. Thus a ring galaxy with a nucleus embedded in the ring-i.e., a ring galaxy of the RN-type, is formed. 相似文献
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E. H. Nikogossian 《Astrophysics》2000,43(1):32-39
The hierarchical structure of the clusters of galaxies A 999, A 1016, and A 1142, which are part of one supercluster, is investigated.
The HTree method is used to determine that A 999 and A 1016 are a single, dynamically bound system consisting of two “cores”
and a common field of galaxies. The composition of the “cores” includes almost all the E and S0 galaxies, the luminosity function
of which is very nearly Gaussian. It is also established that the cluster A 1142 has a nonuniform structure, both in density
distribution and in radial velocity distribution. The location of the maxima in density and in the radial velocity distribution
correlates with the galaxies that are sources of radio and x-ray emission.
Translated from Astrofizika, Vol. 43, No. 1, pp. 45-54, January–March, 2000. 相似文献
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H. Zirin 《Solar physics》1976,50(2):399-404
A large surge was observed on September 17, 1971, part of which, after travelling 200 000 km through the corona, returned to the surface to form a filament. The filament lasted about 30 min, then rose up and returned to the source of the surge. We interpret this as the filling of a semi-stable magnetic trap.The energetics of radio, X-ray, and surge expulsion are estimated. The radio spectrum and flux correspond to a thermal source of area 4 (arcmin)2, T 190 000 K, N
e
2
V 7 × 1048, which is optically deep at 8800 MHz.The soft X-ray source has T 12 × 106 K, N
e
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V 3 × 1048; and if an equal mass is expelled in the surge, the kinetic energy of the surge is similar to the thermal energy of the X-ray source. 相似文献
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