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25 December 2004, Volume 24 Issue 06 Previous Issue    Next Issue

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Configuration Design and Analysis of Liquid Cooled Shield for Cryogenic Capillary Pumped loop Li Qiang Yang Xianfei Xuan Yimin (Nanjing University of Science & Technology, Nanjing 210094) 2004, 24 (06):  .  Abstract ( 1678 )   Save Liquid cooled shield is one of main differences between capillary pumped loop and cryogenic capillary pumped loop. The main function and design process of liquid cooled shield are introduced. Different kinds of configuration design schemes are discussed and their characteristics are accounted for. As a result, it is concluded that the configuration design scheme should be consistent with the operation environment and transport length of CCPL. The liquid cooled shield which cooling load is provided by condenser line is recommended. Related Articles | Metrics

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Design of Flight Simulation Servo System Based on Internal Model PID Robust Control Duan Haibin ** Yu Xiufen *Wang Daobo *Huang Xianghua (*Nanjing University of Aeronautics and Astronautics,Nanjing 210016) (** Center for Space Science and Applied Researth, China Academy of Sciences, Beijing 100080)$$$$ 2004, 24 (06):  .  Abstract ( 1588 )   Save According to the high frequency response, wide speed control, super-low speed, high precision and strong robustness for flight simulation servo system, an effective internal model PID robust control scheme is proposed in this paper. Based on the discussion of mathematic model of servo system, the internal model PID robust control algorithm is derived and applied in a kind of flight simulation servo system. This servo system adopts three-closed-loop construction of current, speed and position. The simulation experiment results show that the internal model PID robust control scheme has excellent tracking performance, strong disturbance rejection ability and robustness. The proposed control scheme can meet the requirements of the flight simulation servo system very well. Related Articles | Metrics

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Numerical Simulation of the Thermal and Humid Environment in Manned Spacecraft Habitation Cabin Huang Jiarong Fan Hanlin (Chinese Academy of Space Technology,Beijing 100086) 2004, 24 (06):  .  Abstract ( 1548 )   Save The mathematical model and boundary conditions of heat and mass transfer in a manned spacecraft habitation cabin are given at first. Then finite-element grid based control volume method is used to discrete the governing equation. The SUR based Gauss-Seidel point iteration method is applied to solve the entire algebraic equation set. Finally, the numerical analysis results of the cabin's flow/temperature/humidity distribution are obtained. Related Articles | Metrics

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Robust Fault Detection Based on the H_∞ Estimation Li Xinguo Chen Hongying (Northwestern Polytechnical University, Xi′an 710072) 2004, 24 (06):  .  Abstract ( 1621 )   Save The H ∞ estimation and optimization methodology ave applied to the fault detection of linear discrete-time uncertain system in order to reduce false alarm rate and improve fault detection accuracy. The key to fault detection based on estimation is to generate residual that are robust against system uncertainties and external disturbance inputs, and that are simultaneously sensitive to fault if occurrs. The robustness requirement of residual generation can be satisfied by application of H ∞ -estimator. The sensitivity requirement can be satisfied by the usage of optimization design that aims to maximize the effect of fault to residuals. Calculation and selection of threshold value are presented. The results are applying to detect fault occurred in sensor and actuator of aircraft in the existence of uncertainties and disturbance inputs. It is shown that the fault detection method based on robust H ∞ estimation and optimization proposed in this paper can reduce false alarm rate by comparing with Kalman filtering. Related Articles | Metrics

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The Development Status and Application of Spacecraft Verification and Test Standards Jin Xunshu (Beijing Institute of Spacecraft Environment Engineering, Beijing 100029) 2004, 24 (06):  .  Abstract ( 1437 )   Save This paper gives an overview of the development status of test standards for spacecrafts and discusses the relationship between environmental testing and reliability testing, and the role of environmental testing in ensuring the spacecraft reliability. It is pointed out that due to the special features of spacecraft, its environmental tests and reliability tests should be considered consistently during verification process, and these standard, if applied correctly, will be able to ensure spacecraft performance requirements and reliability in orbit. Related Articles | Metrics

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Linear Programming Method for the Reconstruction of High Range Resolution Profiles of Space Target Du Xiaoyong Hu Weidong Yu Wenxian (National University of Defense Technology, Changsha 410073) 2004, 24 (06):  .  Abstract ( 1680 )   Save High Range Resolution(HRR)profile is an important feature for the fault diagnosis and identification of space target. Aiming at the classic space targets, this paper discusses the reconstruction and feature extraction of HRR profiles by sparse component analysis. The basis pursuit method which processes real signal is generalized to complex-valued radar returns, subsequently a suboptimal supperreolution algorithm to reconstruct HRR profiles is presented on the basis of constrained least square solution, which can effectively separate the dominant scatters of space target. The numeric results prove the reasonability and validity. Related Articles | Metrics

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Theory and Technology Development of Bio-inspired Hardware Wang Youren Cui Jian You Xia Huang San’ao Yao Rui (Nanjing University of Aeronautics and Astronautics, Nanjing 210016) 2004, 24 (06):  .  Abstract ( 1708 )   Save The concept, the features and the purpose of bio-inspired hardware are introduced. The basic principles of evolvable hardware are illustrated. Key technologies of evolvable hardware are analyzed in details, including evolvable circuits and evolutionary methods. The latest achievements in the field of bio-inspired hardware are summarized. The difficulties of bio-inspired hardware research are discussed, the prospect of bio-inspired hardware and some suggestions for the research are given. Related Articles | Metrics

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The LOS Measurement Error Character Research of Space Early Warning System Zhang Ping Yi Dongyun Wu Yi Tong Li (National University of Defense Technology,Changsha 410073) 2004, 24 (06):  .  Abstract ( 1821 )   Save In the space early warning system,it is very important to analyze and calibrate the LOS measurement error characteristic.In this paper,based on the constructed integrate system error model,the LOS error point distribution,error transfer matrix and error space figure are researched,and some useful conclusions are reuired.Furthermore,an algorithm that can create the random angle error directly is devised without considering the satellite observation platform error. Related Articles | Metrics

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The Application Analysis of Thermistor in Spacecraft Zhang Jiaxun * Wang Hong ** Sun Jialin * (*Chinese Academy of Spacecraft Technology, Beijing 100086) (**Shandong Institute of Spacecraft Electrical Technology,Yantai 264000) 2004, 24 (06):  .  Abstract ( 1737 )   Save This paper firstly presents the requirments for temperature sensor in spacecraft,and then the characteristics of the main temperature sensors used in the flight and ground test of the spacecraft are summarized.Thereafter,by taking the widest used thermistor during the flight operation of spacecraft as the example,its application scheme in spacecraft is introduced.Additionally,the problems of the thermistor associated with the measurement precision,technical feasibility and reliability,which should be noticed,are also introduced. Related Articles | Metrics

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New drivers Developing and Appling Yang Ming (China Academy of Space Technology,Beijing 100086) 2004, 24 (06):  .  Abstract ( 1953 )   Save The developed situation of a new medium power driving model is presented in this paper. Make use of base theory of redundant design, series-parallel separated transistors and resistances the series of integrated circuit are prepared. This paper provides detailed circuit figure and technology parameter on the series model and gives an application example. Test results show that, when used as driving circuit for relay or other switches, can ensure that the single point failure would not appear. Related Articles | Metrics