共查询到18条相似文献,搜索用时 890 毫秒
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绳系卫星系统的运动与控制分析,是绳系卫星应用的基础。本文的数学模型考虑了作用在子星、主星及系绳上的空气阻力以及在伸展与收回阶段主星与系绳之间的质量传递,给出了相应的具体的计算式。应用该数学模型,本文对现有的几种主要控制法,进行了模拟计算,作出评审意见。 相似文献
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空间系绳系统的发展及其应用前景 总被引:1,自引:0,他引:1
空间系绳系统是一项鲜为人知的航天技术,它已有几十年的发展历史。最近,俄罗斯的专家们把这项技术推向了一个新的发展阶段,现作一概括介绍。一、空间系绳系统空间系绳系统是一个人造空间物体(卫星、飞船、货物)的组合体,它们之间用一根长的挠性元件(系绳、电缆、软... 相似文献
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针对空间绳网系统捕获空间碎片后,在轨道转移过程中的精确控制问题,提出一种使用常值拉力将空间碎片拖曳至坟墓轨道的方法。首先,采用牛顿欧拉法建立绳系组合体动力学模型;其次,通过李雅普诺夫方法证明仅使用恒张力即可实现拖曳过程的稳定控制;再次,提出采用常值拉力切换控制律抑制空间碎片的姿态章动,采用基于相平面控制原理的控制律抑制绳系组合体面内面外摆动,规避在轨道转移过程中系绳松弛造成缠绕、系绳张力过大造成断裂或两星接近发生碰撞等风险。最后,通过拖曳离轨全过程仿真分析,校验了所提出控制方法的有效性。 相似文献
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《Acta Astronautica》2001,48(5-12):503-516
In recent years, the use of tethers has been proposed for reduction of space debris either through momentum transfer or use of electrodynamic effects. Tethers have been shown to at least theoretically allow for quick, elegant and cost-effective deorbit of defunct satellites or spent stages. On the other hand, the large risk that tethers themselves may pose to other satellites in orbit has been recognized as well. The large collision area of tethers, combined with operational hazards and meteoroid risk may result in a large orbital exposure. For example, in 1997, the ESA/Dutch 35-km tether deployment of YES from TEAMSAT was inhibited after an analysis of the collision risk for the case the tether operation would fail. The question rises how these two points of view compare to eachother. This paper intends to highlight a representative selection of the proposed tether applications while taking into account the added risks caused by the tethers themselves.Typical applications from recent literature will be briefly described, such as an Ariane 502 spent stage re-entry from GTO and the concept of deboost of defunct satellites by interaction of a conductive tether with the Earth magnetic field.Mass savings of the tethered sytems versus conventional equivalents will be evaluated.Based on a crude risk analysis, involving elements such as mission complexity, dynamic stability, meteoroid risk and orbital life time, a general outline of limiting factors can be given for the various applications. Special attention is reserved for implementation of mechanisms that help reduce this tether risk, such as the DUtether (Tether Degradable by Ultraviolet), utilization of airdrag and solar pressure, the effect of residual current in bare tethers, tether retrieval etc.It is proposed how a net tether-induced mitigation can be compared to that of conventional alternatives, i.e. deboost by rocket engine or a completely passive approach.This comparison is put in the perspective of an ever-increasing occupation of the space environment.It is concluded that tethers can in fact help mitigate the debris risk and that for each application a useful niche can be defined. It is argued that eliminating pollution directly after use of the precious resource of space is not only good custom, but also an important way to make the risk of debris controllable and independent of future trends. Although tethers may have large exposure in terms of area-time product, they deliver a quick cleaning service that may be appreciated by the future users of space. 相似文献
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This paper highlights the design, qualification and mission performance of the tether deployer system on the second Young Engineers’ Satellite (YES2), that featured a tethered momentum transfer. The deployer is designed with a broad range of near-term tether applications in mind. The system contains the tether, including features to enhance safety and wound up in controlled manner onto a spool core, optical deployment sensors, a “barberpole” friction brake controlled by a stepper motor and a triple tether cutter system. To initiate the deployment a spring-based ejection system was developed, and to apply accurate momentum transfer a timer and release system is present on the subsatellite side. A small, 6 kg re-entry capsule was developed as subsatellite. On September 25th, 2007, YES2 deployed a 32 km tether in orbit and gathered a wealth of data. Confidence is gained from the mission results for use of the deployer in future missions. 相似文献
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D Sabath M Krischke W Kast M Kowalczyk M Kruijff E van der Heide 《Acta Astronautica》1997,41(12):841-845
The tether assisted re-entry of small payloads is a highly interesting tool for space transportation especially for the return of small payloads from Space Station ISSA. The small tether mission Rapunzel was initiated in 1991 by the Institute of Astronautics, TU München and the Kayser-Threde Company, to design a low cost and feasible tether experiment for the verification of the tether assisted re-entry. Together with the Samara State Aerospace University, Russia, a mission concept on a Russian Resurs or Photon capsule was developed. Based on this mission a deployer has been designed, mainly based on technology of the textile industry, which insures high reliability at low cost. Recently a similar configuration is being discussed for the ESA-TSE mission.The main work during the recent time was the development and test of the breadboard model of the deployer system. After successfully completing initial ground tests with the deployer, further tests during the ESA Parabolic Flight campaign in November 1995 were conducted. After a short introduction of the overall mission scenario, the planned configuration in orbit, this paper will present the results of the microgravity test campaign onboard the KC-135 aircraft and compare them with the ground test. The deployer showed a good performance during all tests, including ejection of the end-mass, deployment, and braking. Problems that occurred during the tests will be discussed, and solutions for the detected flaws and the results of the redesign now in progress will be presented. These verifications have shown the feasibility of the concept and will lay the base for the planned development of the flight model of the deployer. 相似文献
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Experiments and numerical simulations of an electrodynamic tether deployment from a spool-type reel using thrusters 总被引:3,自引:0,他引:3
The amount of space debris is ever increasing, and pollution of the space environment has become a serious problem that can no longer be ignored. Consequently, the active removal of large space debris from crowded economically useful orbits should begin as soon as possible. The Japan Aerospace Exploration Agency has been investigating an active debris removal system that employs highly efficient electrodynamic tether (EDT) technology for orbital transfer. This study investigates the tether deployment from a spool-type reel using thrusters by means of numerical simulations of an EDT system. The thrusters are used in order to ensure the deployment of a tether with the length of several kilometers. In the simulations using a multiple mass tether model, the key parameters are estimated from various on-ground experiments. By means of the numerical simulations, the dynamics of tether deployment is studied and requirements of thruster needed for the deployment, such as the thrust forces and the periods of thruster activation, are clarified. 相似文献
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YES2 (launching 2007) aims to demonstrate a tether-assisted re-entry concept, whereby payload will be returned to Earth using momentum provided from a swinging tether. Deployment takes place in two phases: (1) deployment of 3.5 km of tether to the local vertical and hold, and (2) deployment to 30 km for a swinging cut. Optimal trajectories are determined for both phases after comparing the effect of different cost functions on the deployment dynamics. Closed-loop control is provided by linearizing the dynamics around the optimal trajectories and solving a receding horizon control problem for a set of linear feedback gains. The controllers are tested in a flexible tether model with large disturbances to the hardware model and environmental variables. Closed-loop simulations show that the system can be controlled quite well using only feedback of length and length rate. 相似文献
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Alternate control laws based on an application of the linear regulator problem are developed for possible use in the operation of the Shuttle-Tethered-Subsatellite system. Control is assumed to be provided only by modulating the tension level in the tether as a function of the difference between actual and commanded tether line length, length rate, in (orbital) plane swing angle and swing angle rate. Necessary and sufficient conditions for stability of the (linear) system motion in the vicinity of its nominal local vertical orientation are developed. By proper selection of the state and control penalty matrices it is possible to obtain faster responses with no increase in maximum power levels for use in station keeping when compared with alternate control strategies. The weighting matrices are adjusted in a piecewise adaptive manner to provide control law gains in order to achieve a smooth deployment history. Successful retrievel is dependent mainly on the initial conditions and the rate at which the commanded length is reduced. 相似文献
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An analysis of the motion of a deployed space system that consists of two end bodies connected by a tether has been considered. One of the bodies has a relatively large ballistic coefficient that ensures aerodynamic braking or the stabilization of the motion of the entire system in relatively low near-Earth orbits. The deployment of this system mainly occurs due to the action of aerodynamic forces. Several ways of deploying the system have been analyzed, including (1) the uncontrolled release of the tether with hardly any braking; (2) deployment with constant braking force; (3) the dynamic control law without feedback, when the resistance force varies according to a set program; (4) a kinematic control law with feedback when programs are set for varying the velocity and length of the tether release. To analyze the dynamics of the system, a mathematical model of motion has been constructed in which the motion of the end bodies relative to their centers of mass is taken into account. 相似文献