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25 October 1998, Volume 18 Issue 05 Previous Issue    Next Issue

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ON INTELLIGENT ADAPTIVE CONTROL OF A TYPE SPACECRAFT Li Zhibin Wu Hongxin (Beijing Institute of Control Engineering,Beijing 100080) 1998, 18 (05):  .  Abstract ( 1506 )   Save According to the requirements of modern spacecraft control,this paper presents a hierarchical intelligent adaptive control system based on the description of plant feature model knowledge.First,the theorem on the equivalent low order time variable model of high order plant and the theorem on general PD feedback compensation are derived.Then the basic design method of the hierarchical intellitgent adaptive controller is introduced.Finally,the intelligent adaptive control method is applied to attitude control of a type spacecraft with deploying the solar panels.The simulation result shows that the intelligent adaptive control method presented is effective and feasible. Related Articles | Metrics

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THE MOTION CENTRE OF TETHERED SATELLITE SYSTEMS Zhu Renzhang (Beijing University of Astronautics and Aeronautics,Beijing 100083) Lin Huabao (Chinese Academy of Space Technology,Beijing 100081) 1998, 18 (05):  .  Abstract ( 1750 )   Save The centre of mass of a tethered satellite system is not the motion centre of the system.The expressions of the position of the motion centre in the tether are given,and the formulae of calculating the tension in the tether are presented,in terms of which frequencies of libration can be determined accurately. Related Articles | Metrics

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FROZEN ORBIT BASED ON BROUWER’S MEAN ORBIT ELEMENTS Yang Weilian (Beijing Institute of Spacecraft System Engineering,Beijing 100086) 1998, 18 (05):  .  Abstract ( 1985 )   Save In this paper frozen orbit is investigated based on Brouwer's mean orbit elements .It has been found that the orbit elements of frozen orbit describe an exact circular orbit.Furthermore,a new explanation to the characteristics of frozen orbit is presented.In addition,the variations of orbit eccentricity corresponding to the changes of orbit inclination is analyzed under the earth gravitational field including only J 2 and J 3.It can be seen that the abnormal behavior near critical inclination is still kept. Related Articles | Metrics

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COAXIAL ATOMIC OXYGEN SIMULATION FACILITY AND ITS PROPERTIES Wang Jingyi Yu Zhizhan Cai Chun Li Hong Zhang Jingqin (Lanzhou Insititute of Physics,Lanzhou 730000) 1998, 18 (05):  .  Abstract ( 1629 )   Save The principle of the facility operation is introduced.The facility for simulating atomic oxygen in low Earth orbit adopts coaxial microwave plasma source.The components of the facility and their functions are described.The measuring methods and measured results for performances are described.It is proved that energy of atomic oxygen can be controlled in the range of 5eV～10eV,beam intensity of atomic oxygen is about 4×10 15 Atom/cm 2·s and the content of oxygen ions is less than 0 1% in atomic oxygen beam. Related Articles | Metrics

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STUDY OF ORBIT DETERMINING BY USE OF RATE DATA OF CONTINUOUS WAVE RADAR Yi Dongyun Zhu Jubo Wang Zhengming (National University of Defense Technology,Changsha 410073) Guo Junhai (Research Institute of Measurement and Communication Technique,Beijing 100094) 1998, 18 (05):  .  Abstract ( 1797 )   Save In continuous wave radar tracking system,system error of range data is usally large,while range rate data has high precision.How to use rate data to determine orbit of a spacecraft is important.The theoretical analysis and actual computation results show that orbit determining by use of rate datas point by points has very poor precision and isn't valuable.The detailed study is given and the new nonlinear spline function method of orbit determining by use of rate data is presented.The actual algorithm and the error propagation formula are given Results show that the new method has high precision.The actual application shows that the new method is successful and widely valuable. Related Articles | Metrics

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MIXED MODE INTERLAMINAR FRACTURE OF HIGH MODULUS CARBON EPOXY COMPOSITES Zhao Shixi Wang Bo Chen Huanchun (Beijing University of Aeronautics and Astronautics,Beijing 100083) Lin Daqing Dong Yi Xiao Shaobai (Beijing Spacecrafts,Beijing 100080) 1998, 18 (05):  .  Abstract ( 2115 )   Save The interlaminar fracture behavior of two high modulus carbon/epoxy composites (HM/4211 and HM/TDE86) has been investigated in mode Ⅰ,mode Ⅱ and mixed mode.The double contilever beam (DCB) test,the end notched flexure (ENF) test and the mixed mode bending (MMB) test were conducted to determine the interlaminar fracture toughness and the failure locus in mixed mode for the two composites.The data and results obtained from this investigation are useful for material selection and quality assurance in space structure application,and furthermore,for establishing design allowable used in damage tolerance analyses of composite structures made of these materials. Related Articles | Metrics

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MEDICAL COUNTERMEASURE TO HEAT STRESS DURING SPACE FLIGHT Pang Cheng Chen Jingshan (Institute of Space Medico Engineering,Beijing 100094) 1998, 18 (05):  .  Abstract ( 1674 )   Save Since the occurrence probability of heat emergency in the manned space activities is relatively high ,heat stress should be paid more attention to relieve its effects on crewmembers.This paper provided some methods for selection and training of astronaut candidate on the basis of significant relationships between them and capabilities of heat tolerance It is suggested that adaptive index of cardiac function and maximaum oxygen uptake ( O 2 max ) should be used as selective targets and several physical fitness training should be carried out in order to get further improvements of heat tolerance. Related Articles | Metrics

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A HEAT SINK OF PHASE OF CHANGE THERMAL STORAGE/RADIATION FOR EXTRAVEHICULAR ACTIVITY Zhao Chaoyi Yuan Xiugan (Beijing University of Aeronautics and Astronautics,Beijing 100083) Sun Jinbiao (Institute of Space Medico Engineering,Beijing 100094) 1998, 18 (05):  .  Abstract ( 1489 )   Save The specific technologies investigated in heat rejection system for EVA are discussed at first.A heat sink of phase of change thermal storage/radiation is introduced then.The performance requirements critical to the design of the nonventing EVA heat rejection system and the calculation methods and selection criteria for phase change materials are presented. Related Articles | Metrics

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A PROPULSION SYSTEM ANALYSIS FOR SINGLE STAGE TO ORBIT VEHICLE Huang Weidong Wang Kechang Chen Qizhi (National University of Defense Technology,Changsha 410073) 1998, 18 (05):  .  Abstract ( 2014 )   Save Nine schemes of bipropallent and tripropallent engine are selected,and their performances and masses are also calculated.The effects of the propulsion system on the dry mass of the single stage to orbit vehicle are analyzed,the propulsion system being made up of these engines.The calculated results show that the vehicle with main propulsion system made up of tripropallent engines has the minimum dry mass. Related Articles | Metrics

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THERMAL NETWORK ANALYSIS OF AN EXPERIMENTAL SPACECRAFT Weng Jianhua (Tongji University,Shanghai 200092) Pan Zengfu (Beijing Institute of Spacecraft System Engineering,Beijing 100086) Min Guirong (Chinese Academy of Space Technology,Beijing 100081) 1998, 18 (05):  .  Abstract ( 1549 )   Save On basis of a general method for designing spacecraft thermal control system,thermal network analysis method,calculated the temperature field of an experimental spacecraft,and the results were compared with the experimental data.The difference between calculation results and experimental data of most equipment temperature is less than 3℃,a few is between 3℃ and 5℃,and few than 5℃ after thermal network correction. Related Articles | Metrics

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DESIGN STANDARD RETURN TRAJECTORY OF MANNED SPACECRAFT BASED ON GENETIC ALGORITHM Wu Meiping (National University of Defense Technology,Changsha 410073) 1998, 18 (05):  .  Abstract ( 1809 )   Save According to the task,must design a standard return trajectory which is reference trajectory for guidance when a manned spacecraft returns.This paper studies that Genetic Algorithm (GA) is used to automatically design the standard return trajectory.Simulation shows that GA has advantage for designing the standard return trajectory.The results of simulation are fit to task. Related Articles | Metrics

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THE DISJOINT ALGORITHM IN MULTISTATE SYSTEM RELIABILITY ANALYSIS Zeng Liang (National University of Defense Technology,Changsha 410073) 1998, 18 (05):  .  Abstract ( 1835 )   Save In this paper studed the algorithm to realize the disjoint calculation in multistate system.In the multistate system reliability analysis,often need to execute disjoint calculation of sets,but it is very difficult in multistate system for the component multistate characteristics.The paper first introduces the cube expression method of sets,and sets up relevant operation rules.Based on the rules,given the disjoint algorithm for multistate system.The example in the paper proves that the method is valid. Related Articles | Metrics