Loading...

Table of Content

    25 December 2001, Volume 21 Issue 06 Previous Issue    Next Issue
    For Selected: Toggle Thumbnails
    Fault-Tolerant Sliding Predictor for Sampled Data Series
    Hu Feng Wen Xisen (The National University of Defense Technology,Changsha 410073) Sun Guoji (Xi'an Jiaotong University,Xi'an 710049)
    2001, 21 (06):  . 
    Abstract ( 1835 )   Save
    A series of iterative identification algorithms is given for parameters of the curve fitting model.Under the model,the approach for fault-tolerant predicting algorithm is built in this paper.This fault-tolerant predictor is practical.The simulation results show that the new predictor has the capability to properly overcome bad influence coming from outliers.
    Related Articles | Metrics
    Dynamic Analysis of Suspended Equipments with Viscoelastic Boundary Isolators
    Zhao Huiguang * Ma Xingrui ** Feng Jisheng * (*Beijing Institute of Space System Engineering,Beijing 100086 ) (**China Aerospace Science & Technology Corporation,Beijing 100833)
    2001, 21 (06):  . 
    Abstract ( 1832 )   Save
    Vibration of high precision equipments in spacecraft can be greatly suppressed with viselastic isolators suspended.In this paper,basic motion equations used for time domain and frequency domain analysis on the kind of problems are derived by means of combining FEM of elastic body and standard solid model of viselastic materials.A convenient numeric simulation method on solution of time domain equation is also given.As a demonstration,dynamic simulation and analysis of instrument panel with viscoelastic isolators suspended are performed.The effects on vibration from characteristic parameters of viselastic isolators are also analyzed with pilot study.
    Related Articles | Metrics
    Re-discuss the Solution of Constrained and Unconstrained Mode for a Kind of Flexible Structure
    Shan Jinjun Liu Dun Qi Naiming Zhao Baoshan (Harbin Institute of Technology, Harbin 150001)
    2001, 21 (06):  . 
    Abstract ( 1466 )   Save
    Considering a kind of flexible structure, which has uniform flexible beam,attached to the center rigid body and there are point mass and point moment of inertia.The solution of constrained and unconstrained mode for the equations of motion is analyzed and the general equations of frequency are obtained.Based on these analyses, quantitative comparison between constrained and unconstrained mode frequency with different flexible/rigid body inertia is made.The theoretical basis for modeling and design of controller of such flexible system is provided.
    Related Articles | Metrics
    An Algorithm on the Real-Time MVMTTS Base on Extended Kalman Filter
    Duan Xiaojun Zhou Haiyin (National University of Defense Technology,Changsha 410073)
    2001, 21 (06):  . 
    Abstract ( 1540 )   Save
    As far as the real time data processing of MVMTTS (multi velocity measuring trajectory tracking system) is concerned,the observation equations and state equations of extended Kalman filter are deduced.And the precision of data fusion is provided.Theoretical analysis and simulation show that the method is applicable to data processing in space flight.
    Related Articles | Metrics
    The Anisotropy of Acceleration of Body in Move in the Gravitational Field
    Xu Kuan (Tsinghua University,Beijing 100084)
    2001, 21 (06):  . 
    Abstract ( 1690 )   Save
    By the action of gravitation or other forces,the acceleration of the body in move is anisotropic.Namely,in case the magnitude of forces is equal,the acceleration,if the direction of force and the direction of the velocity of body in move are perpendicular,is bigger than the acceleration,if the direction of the velocity and the direction of force are parallel.When the theory of the additional acceleration for celestial mechanics is used,the "superabundance" precession angle of a planet perihelion and the deflexion angle of photon on surface of the sun are calculated accurately,and the lately discoverable "oddity acceleration" of aircraft is qualitative explained.Thus,the movement orbits in gravitation field for the planets,the aircraft,the photon and so on--complete different objects can be described with totally same physics mechanism--the extended Newtonian Mechanics by the anisotropy of acceleration of body in move.
    Related Articles | Metrics
    The Mitigation Measures of Space Debris and the Strategy of Study
    Luo Gangqiao (Beijing Institute of Spacecraft System Engineering,Beijing 100086)
    2001, 21 (06):  . 
    Abstract ( 1655 )   Save
    A lot of spacecrafts will be launched into space along with the development and progress of human space science.Because of lack of effective recovery means,more and more invalid spacecrafts abandoned will be accumulated in space with time increasing.No spacecraft could be launched into space if mitigation measures aren't adopted.The mitigation measures of satellites and launchers must be taken into account for protection of space environment and decrease of space debris.Some existing technology will be applied into debris mitigation.The strategy and range of space debris mitigation study will be presented.
    Related Articles | Metrics
    Spacecraft Environment Engineering: the Past and the Future
    Jin Xunshu (Beijing Institute of Spacecraft Environment Engineering,Beijing 100029)
    2001, 21 (06):  . 
    Abstract ( 1724 )   Save
    WT10.5,10.BZ]The three main aspects of the development of spacecraft environment engineering in the 20th century are reviewed,which points out that the environment engine ering and environmental testing has been playing an important role in the development of space technology and the verification work.The research work dealing with the space environment effects and the simulation techniques is the foundation for the environment engineering,and the computer and digital techniques,which has pushed the spacecraft environment engineering and test techniques forward greatly.In the new century,the spacecraft environment engineering will continuously pay great attention to improve the test efficiency and at the same time to reduce test costs and time.Suggestions are proposed for developing the spacecraft environment engineering in China.
    Related Articles | Metrics
    Completion of Spacecraft Rendezvous Under Error Condition
    Wu Meiping Wu Ruilin (National University of Defense Technology,Changsha 410073)
    2001, 21 (06):  . 
    Abstract ( 1682 )   Save
    While guidance project of the spacecrafts' rendezvous is designed,completion of rendezvous under error condition is considered.Two impules correct method to guide and correct errors during rendezvous is designed,basing on the horizontal impulse multi segmental arcs rendezvous project.Results of simulation shows that guidance is feasible,which doesn't influence advantages of rendezvous project.
    Related Articles | Metrics
    A New Method of Momentum Unloading Utilizing Geomagnetic Field
    Li Taiyu Zhang Yulin (Inst.of Aerospace and Material Engineering,National Univ. of Defense Technology,Changsha 410073)
    2001, 21 (06):  . 
    Abstract ( 1614 )   Save
    Firstly the dynamic characteristic of geomagnetic intensity in a circular is analyzed.Then the magnetic dipoles produced by magnetorquer are expanded in Fourier series. On the basis of the sum of unloaded angular momentum,the magnetic dipoles are figured out according to the theory of optimal control.The stability of control low and simulations are given,which shows the method is simple and the energy can be saved very much.
    Related Articles | Metrics
    Vanadium Dioxide Films Technique and Electrical Switching Property
    Xu Min Qiu Jiawen Zhao Yinzhong Wang Jiebing He Yanchun Li Qiangyong (Lanzhou Institute of Physics,Lanzhou 730000)
    2001, 21 (06):  . 
    Abstract ( 1856 )   Save
    A sol gel method is described for preparing high quality vanadium dioxide thin films which exhibit an abrupt resistivity change of 2~3 order of magnitude at about 60℃~80℃ on non crystal substrate.The method consists of four processes:quenching, coating ,drying and vacuum heat treatment.These processes show strong effects on the properties of the final film.The effects of the drying process on the film blistering and the effects of film thickness,quenching temperature,and heat treatment time on the resistivity switching property are studied.XRD (x ray diffraction), XPS (x ray photoelectron spectroscopy) are utilized to study the drying process,structure and characterize the films.
    Related Articles | Metrics