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1.
以极地天文望远镜为应用背景,研制了一种低温微位移促动器,并在室温和低温条件下进行性能测试实验,获得了低温微位移促动器的性能指标。分析了3种常见的大行程高精度微位移促动器的结构形式,选择位移缩放式作为低温微位移促动器的基本结构。微位移促动器采用低温步进电机作为驱动元件,以具有特殊消隙结构的螺旋传动作为位移缩放机构,实现了高刚度、耐低温、结构紧凑、密闭性好的微位移促动器的设计。开展了微位移促动器的性能测试实验,结果表明:所设计的低温微位移促动器在室温条件下的步进精度达到1μm±0.082μm,并且满足负载能力的设计要求;低温条件下步进精度可以达到2μm±0.404μm。研制的微位移促动器将为拼接式极地天文望远镜的建设提供重要的技术支持。  相似文献   

2.
以环形太阳望远镜为应用背景,研制了一种基于步进电机的位移促动器,并进行了性能测试实验,获得了位移促动器的性能指标。分析了常见的大行程、高精度位移促动器的结构形式,选择位移缩放式作为位移促动器的基本结构。该位移促动器采用步进电机集成行星减速器作为驱动元件,以具有特殊消间隙结构的螺旋传动作为位移缩放机构,为实现高分辨率、高刚度和高精度的位移促动器设计,开展了位移促动器的性能测试实验,结果表明:该位移促动器轴向位移量程为±2 mm,不同负载下均能实现1 μm的步长分辨率,位移闭环输出精度优于1 μm。研制的位移促动器为环形太阳望远镜的建设提供重要的技术支持,并为其它精密光学镜面支撑系统的工程应用提供参考。  相似文献   

3.
针对2 m环形太阳望远镜主镜轴向支撑设计需求和指标,研制了一种基于波纹管的气压式力促动器,开展了全面实验测试。该气压式力促动器采用可伸缩高强度、高弹性金属波纹管作为核心器件,采用线性轴承作为导向机构,并集成单向压力传感器作为力反馈元件,同时在设计中考虑了安装调整工艺便捷性。经测试,该气压式力促动器单向输出力达200 N,输入气压与输出力线性度误差小于2%,力分辨率小于0.23 N,闭环力精度优于±0.3 N。测试结果验证了该气压式力促动器原理和结构简单,安装维护工艺良好,达到了设计指标,可满足2 m环形太阳望远镜主镜轴向支撑的需求。研制工作为气压式力促动器的设计细节改进及主镜支撑系统的工艺优化奠定了基础,并可为其它精密光学镜面支撑系统的工程应用提供参考。  相似文献   

4.
根据FAST主动反射面需求评估了对促动器性能的要求,依促动器评估参数需求设计了针对电流、功率、温度、负载、位移、限位信号的监测系统,确定各监测信号传感器选型,完成监测系统的组装制作,并将其应用于实验,实现促动器的在线监测功能以及促动器无人值守实验,针对以往促动器实验时人工巡检故障的离线监测有很大改进,在精度以及历史信息记录上都有质的提高,进行了长期的促动器调试与监测.  相似文献   

5.
随着光学天文望远镜口径不断增大,望远镜主镜多采用拼接镜面形式,而微位移促动器作为镜面拼接技术的关键部件,始终是研究的热点之一。以双螺旋滚珠丝杆代替传统机械式微位移促动器中减速器加滚珠丝杆结构,利用差动螺旋原理进行微位移输出,使用伺服电机作为驱动电机,并对负载时电机所需的转矩进行分析。微位移促动器的输出位移精度、行程及负载能力是重要技术指标,本文从这三方面的要求出发,开展性能测试。实验结果表明,该微位移促动器总行程为5 mm,理论最大可承载1 200 N,在200 N的负载下实现200 nm的步长分辨率,开环单向位移精度优于0.65μm,闭环单向位移精度优于0.2μm。验证了所提出的微位移促动器具备高精度、大行程和高负载的要求,为我国未来大口径天文望远镜的设计提供技术储备。  相似文献   

6.
随着毫米波天文学和空间通信的重要性日益提高, 对天线性能提出了越来越高的要求, 而天线性能往往受到其反射器表面精度的限制. 微波全息技术是一种快速有效的检测反射面天线表面轮廓的测量技术. 通过微波全息测量得到天线口径场, 计算天马65m射电望远镜反射面与理想抛物面的偏差. 天马65m射电望远镜的主反射面板是放射状的, 有14圈. 面板的每个角都固定在面板下方促动器的螺栓上进行上下移动, 且相邻面板交点处的拐角共用一个促动器. 采用平面拟合的方法可以计算各块面板拐角处的调整值, 但是同一个促动器会得到4个不同的调整量. 通过平面拟合, 同时以天线照明函数为权重的平差计算方法得到相邻面板拐角的一个平差值, 即天马65m射电望远镜1104个促动器的最佳调整值. 通过多次调整和新算法的应用, 天马65m射电望远镜反射面的面形精度逐渐提高到了0.24mm.  相似文献   

7.
介绍拼接镜面主动光学计算机控制的设计思想和研制的方法。计算机通过接口控制6套微位移促动器实现了同步工作;控制维持三块子镜的共焦和共面;采用6套电容式的微位置传感器来检测共面的位置,作为计算机闭环控制的反馈信号。位移促动器的控制分辨率为5nm左右。系统控制的位置误差rms值小于25nm。  相似文献   

8.
即将用于新疆奇台110 m射电望远镜(Qi Tai radio Telescope,QTT)的促动器需在-40~60℃范围内满足±15μm的精度要求.由于在无任何补偿的情况下,热误差可以达到约400μm,因此需要建立热误差模型,以预测促动器位移随温度的变化规律,并在此基础上进行位移主动控制补偿,从而保证促动器在给定温度...  相似文献   

9.
提出了理想反射面及2参数、5参数和6参数最佳吻合抛物面方法,计算大型卡氏天线结构重力变形后主反射面板的调整量和对应的副反射面调整量,同时分析馈源偏焦对天线电性能的影响.以上海天文台天马65 m望远镜(TM65m)为研究对象,综合对比分析促动器调整量、6杆并联机构调整量、主反射面精度及偏焦后天线指向变化等,认为针对实际结构而言,经过调整修正后,6参数最佳吻合抛物面方法可以作为高精度天线理想的计算面板变形主动控制量方法,计算结果为天线的主动控制提供初调数据.  相似文献   

10.
本文用计算方法,找出了可调Lyot双拆射滤光器的积分透过率是守恒的:由最原始级确定的滤光器周期中,不管各级的调节波长装置如何移动,即不管各级的透过带位置如何放置,其滤光器的积分透过率守恒,恒等于主带(最厚级透过带宽)的半宽.据此特征以及太阳方和斐线线心光度极小的特征,本文提出一种方法,只需用光电倍增管和普通微安表,直接利用装有双拆射滤光器的太阳望远镜,就能方便地调到所用谱线中心. 对几个选定的波带位置,从理论上计算和实际上观测滤光器的总透光量,并进行比较,推算了太阳磁场用窄带双折射滤光器的总附加散射光量,这种散射光是由光学元件不完善等所引起的。无论太阳磁场测量或太阳单色光度测量都迫切需要了解这种附加总散射光量.  相似文献   

11.
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   

12.
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.   相似文献   

13.
14.
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   

15.
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   

16.
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   

17.
从设计、制作和测试方法方面介绍了一种制冷接收机低温杜瓦温度监测系统.主要阐述了低温杜瓦对温度监测系统的要求,根据要求合理设计,涉及到各种器件参数的选择以及布局制板等问题,为高精度温度采集系统的硬件设计提供了理论依据.设计采用多路模拟输入通道即集中采集方式,根据系统的需要划分不同的功能区块进行电路设计.制作完成的温度监测系统先后经调试校准、实验室模拟测试以及安装在乌鲁木齐25m射电望远镜18cm制冷双极化接收机上测试,各项设计功能都能很好地实现,并且运行可靠.  相似文献   

18.
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 2 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   

19.
20.
In a two-component cycle, the generation of the dipole field by a separate mechanism as well as the strong link occurring, with a 5–6-yr delay, between the sunspot cycle and the preceding dipole cycle, sets in new terms the problem of the mechanisms at the origin of the solar cycle. In this paper, from various series of synoptic solar data, we identify some of the mechanisms to incorporate in a model of a two-component solar cycle. The first one concerns the dipole field which is not a surface phenomenon. We establish the cyclic behaviour and the various properties of the dipole-field sources which are deep-seated in the solar interior and have a rigid rotation of about 27 days. We identify two cyclic phenomena which, in each hemisphere, link with a 5–6-yr delay, the dipole field generation which occurs at high latitudes, to the bipolar field emergence occurring at sunspot latitudes. They are the signatures of a coupling mechanism taking place deep in the solar interior. Then we study the constraints imposed on the mechanisms of the sunspot field generation both by a two-component cycle and by new observational results. These last ones concern the links occurring between the birth of new sunspot groups and the occurrence of pre-existing features of the photospheric field and of pivot-points in rigid rotation at 27.3 days.Our final discussion is devoted to a first sketch of the distribution of the relevant mechanisms among separate regions of the convective zone. Unfortunately neither the helioseismology, nor our data analysis has yet supplied us with appropriate pieces of information for building a physical model of this two-component cycle.  相似文献   

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