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25 October 2000, Volume 20 Issue 05 Previous Issue    Next Issue

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Object Capture Adaptive Control for Space Robot Wang Haoying Wang Jing Wu Hongxin Liang Bin (Beijing Institute of Control Engineering,Beijing 100080) 2000, 20 (05):  .  Abstract ( 2518 )   Save Kinematics of the space robot system with an attitude controlled robot is derived and the generalized Jacobian is given.Desired trajectory of the robot end effector in inertial space is planed based on the movement of the object.Kinematics and dynamics can be linearized by a set of combined parameters,the update law of the parameters is designed respectively.Adaptive control is adopted in joint space.When the dynamic parameters are unknown,the algorithm can keep asymptotic stable of the system,and the attitude of base is remained when the end effector is tracking the desired trajectory to capture the object.Planar two joint space robot is simulated to verify the validity and effectiveness of the algorithm. Related Articles | Metrics

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Calculation Method for Proton Single Event Upset Cross Section He Chaohui Chen Xiaohua Li Guozheng Yang Hailiang (Northwest Institute of Nuclear Technology,Xi'an 710024) 2000, 20 (05):  .  Abstract ( 3142 )   Save A model and a simulation method for calculating the proton Single Event Upset (SEU) cross section are presented by analysis of proton reactions in silicon.The variety,production cross section,energy spectrum and double differential cross section are calculated for the secondary particles produced by reactions of high energy protons in silicon.The reaction in silicon is simulated with Monte Carlo method.The range of secondary particles is computed with TRIM code.The energy and charges deposited by secondary particles are calculated in sensitive volume in memory cell.Whether a proton induced SEU is determined by comparing the charges with the critical charge and the proton SEU cross section is obtained.The calculation results are in agreement with the experimental results. Related Articles | Metrics

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Guidance Control for Lunar Gravity-Turn Descent Wang Dayi (Harbin Institute of Technology,Harbin 150001) Li Tieshou Yan Hui (Beijing Institute of Control Engineering,Beijing 100080) Ma Xingrui (China Aerospace Science Corporation,Beijing 100830) 2000, 20 (05):  .  Abstract ( 1893 )   Save The feedback linearization method is utilized to generate guidance laws to track desired height and velocity profiles respectively for lunar gravity-turn descent.The Lyapunov stability of the two following control systems is demonstrated in use of related theory of differential geometry.Furthermore,an attainable set for initial conditions of the gravity-turn descent is deduced according to the constraints of thrust,fuel and states of the soft landing system.Finally,an example of the following guidance law is presented,which needs only slant range,velocity and local vertical information.This method may allow simple guidance with less complex sensors for low-cost soft landing on the lunar surface. Related Articles | Metrics

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Localization Precision Analysis of Three Satellites Cluster for Time-difference Localization Wang Haili Ren Xuan Chen Lei (National University of Defense Technology,Changsha 410073) 2000, 20 (05):  .  Abstract ( 2435 )   Save Three satellites cluster for time-difference localization is applied to find the radar beacon position on the ground.The geometry dilution of precision factor from the principle of time-difference localization derived.Then,the effects of radar beacon position,cluster geometry and satellite altitude on the geometry dilution of precision factor are analyzed.Some useful references for satellite cluster configuration are presented. Related Articles | Metrics

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Satellite Keeping Operation System for Chinese SJ-5 Li Xiaotong (Beijing Institute of Spacecraft System Engineering,Beijing 100086) 2000, 20 (05):  .  Abstract ( 1848 )   Save Satellite Keeping Operation (SKO) system first applied to chinese mission is an comprehensive automatic system which accomplishes satellite operating management, autonomous control, information transmission and ground-to-satellite loop operation. SKO is the flexible satellite-borne system which cooperates and schedules contact between various satellite components with use on-board network to perform dynamic stream tasks including information stream, action stream and energy stream. SKO has several innovations as follows: multilevel control, embedded management executive unit, field network technology, hardware/software encapsulation technology, utilization of the commercial RTOS, compatible package telemetry, compound tele-command and tele-operation technology, data multi-path and reconstruction technology, test-bed technology, radiation shielding technology, etc. Autonomous capability and intelligence of the satellite are enhanced and risk of the mission is decreased by the application of SKO to SJ-5 mission. Also top-level reliability and efficiency of mission operation are improved. Related Articles | Metrics

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The Progress in the Design of Propellant Management Devices for Surface Tension Tanks Zhang Tianping (Lanzhou Institute of Physics,Lanzhou 730000) 2000, 20 (05):  .  Abstract ( 1853 )   Save The propellant management device(PMD)is the most important component of a surface tension tank.A survey of the propellant management device technology is presented briefly,and the current progress in PMD design is summarized.The applied and advanced methodologies of the PMD design are analyzed from the five aspects of the mission requirements,reliability,long life,test needs and serialization,these are also explained and commented combining with particular examples. Related Articles | Metrics

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Effects of Radiation on Mechanical Properties of Honeycomb Sandwich Structure Zhang Jianke Ji Yongfu (Lanzhou Institute of Physics,Lanzhou 730000) 2000, 20 (05):  .  Abstract ( 1730 )   Save The mechanical properties of a kind of honeycomb sandwich structure with the face of carbon fiber composites and aluminum honeycomb under particle radiation,ultraviolet ray are measured.On the basis of a lot of experimental data,the laws of particle radiation and ultraviolet ray effecting the mechanical properties are found and the effecting mechanism is analyzed.The law possessing some general significance and the research direction of anti-radiation of honeycomb sandwich structure are given. Related Articles | Metrics

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Jacquin Fractal Image Coding Combined with Wavelet Transform Zhou Juan Luo Jianshu Xie Duanqiang (National University of Defense Technology,Changsha 410073) 2000, 20 (05):  .  Abstract ( 1506 )   Save A fractal image coding combined with wavelet decomposition is presented.Jacquin fractal image coding is very simple.But when it is encoding,it takes a long time and sample method of Domain has its shortcoming.In order to solve this question,a new fractal image coding based on discrete wavelet transformation is introduced.The algorithm is:First,the image is decomposed into different channels by discrete wavelet transformation.Second,a domain block and an affine mapping are searched for each part of image block respectively within low frequency of wavelet coefficients.Simulation shows that the quality of the image is improved greatly. Related Articles | Metrics

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The Natural Vibration Performance Analysis of Lateral Vibration for the Launch Vehicle of Strap-on Boosters Ma Jinhua (Shandong Architectural and Civil Engineering Institute,Jinan 250014) Song Xiangeng Wang Junqi (Shandong Technology University,Jinan 250061) He Dexin (China Aerodynamics Research and Development Center,Mianyang 621000) 2000, 20 (05):  .  Abstract ( 1498 )   Save The natural vibration performance of the over hanging beam for the launch vehicle of strap-on boosters is investigated using the subspace iteration procedure of ALGOR general program for the finite element method.Two kinds of calculation models are studied,one hinge the upper joints of boosters to the core vehicle and fix the lower joints to it,and the other fix both the upper joints and the lower ones of boosters to the core vehicle.Experiment result shows that the method of this paper is efficient. Related Articles | Metrics

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Application of Hybrid Interface Modal Synthesis Technique to Jitter Responses Analysis and Simulation of Remote Sensing Satellites Wang Yueyu Yu Dengyun Qu Guangji (Beijing Institute of Spacecraft System Engineering,Beijing 100086) Zhang Yong Zhao Jingwen (Harbin Institute of Technology,Harbin 150001) 2000, 20 (05):  .  Abstract ( 1689 )   Save When the high resolution remote sensing satellite performs earth observation,various motions of onboard motive components will make the body of satellite produce jitter responses,which affect the image quality.The modeling of jitter responses analysis of remote sensing satellite based on hybrid interface modal synthesis technique is introduced.In addition,a sub-matrix algorithm to increase computational efficiency is presented.Numerical results of jitter analysis of remote sensing satellite under the disturbance of main disturbing resources are also given. Related Articles | Metrics

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Zerotree Coding of Satellite Images and Analysis of its Effect Qiao Shidong Luo Jianshu (National University of Defense Technology,Changsha 410073) 2000, 20 (05):  .  Abstract ( 1655 )   Save A encoder based on the kernel idea of EZW,the zerotree coding and the SAQ,is redesigned.According to this encoder,the satellite images (after WT) are encoded.The compress effect of zerotree coded satellite images is analyzed.By adopting six-symbol zerocoding symbol set,the “dominant”pass and the “subordinate”pass in EZW algorithm are combined.In the procedure of encoding the zerotree-symbol bit-stream by a lossless method,the compress effect of several other algorithms but the adaptive arithmetic coding method is compared and a more suitable lossless coding algorithm is proposed according to the experimental results. Related Articles | Metrics