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    25 October 2011, Volume 31 Issue 5 Previous Issue    Next Issue
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    Constructing China's Ocean Satellite System to Enhance the Capability of Ocean Environment and Disaster Monitoring
    YANG Bao-Hua
    2011, 31 (5):  1-8.  doi: 10.3780/j.issn.1000-758X.2011.05.001
    Abstract ( 2126 )   PDF (596KB) ( 1781 )   Save
    Ocean satellites are the important means to obtain the data of ocean environment and disaster monitoring, and play a huge role on ocean disaster prevention and mitigation as well as ocean scientific  research. The elements of the ocean environment observation and the application status of ocean observation satellites in the ocean environment and disaster monitoring were analyzed. Combined with foreign ocean satellite development trends and China's demand, the development suggestions of constructing China's ocean satellite system was proposed to enhance the ocean environment and disaster monitoring capability,to promote the development of China's ocean industry,and to accelerate the construction of national economy and coastal defense security.
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    Adaptive Controller for Spacecraft Attitude Maneuver Based on Extended State Observer
    YUAN Guo-Ping, SHI Xiao-Ping, LI Long
    2011, 31 (5):  9-17.  doi: 10.3780/j.issn.1000-758X.2011.05.002
    Abstract ( 1763 )   PDF (462KB) ( 1139 )   Save
    To deal with spacecraft three axis large attitude maneuver with the external disturbances and actuator uncertainties, a new adaptive output feedback controller was presented based on the extended state observer. Firstly, an attitude dynamic model by the Momentum theorem and Euler method was established. Secondly, based on the fact that the extended state observer could minimize the nonlinear coupling and external disturbances, the adaptive output feedback control strategy was developed only with the attitude angle output, which could compensate the control toque error during the large angle attitude maneuver. Finally, simulation results show that the precise attitude maneuver can be accomplished and the angles can converge to the desired states for different cases.
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    Optimal Control of Spacecraft Fly-around Releasing Using Continuous Thrust Based on Gauss Pseudospectral Method
    DUAN Chuan-Hui, DONG Yun-Feng
    2011, 31 (5):  18-24.  doi: 10.3780/j.issn.1000-758X.2011.05.003
    Abstract ( 2437 )   PDF (378KB) ( 1241 )   Save
    An optimal orbit maneuver method based on continuous low thrust was presented to solve relative motion control. With C-W equation, analytic resolution of relative motion was derived. The relative velocity and relative position constrains for stable formation without control were discussed. The constrains were treated as final conditions, and the relative position and relative velocity of depart were treated as initial conditions. These conditions together with relative equation constructed an optimal orbit maneuver problem. The Gauss pseudospectral method was applied to translate the optimal problem into nonlinear programming which was solved by sequential quadratic programming. The numerical simulation indicates that the Gauss pseudospectral method can effectively converge to optimal solution.
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    Analytical Solution of Two-Point Boundary Value Problem for Spacecraft Relative Motion
    YUAN Yun-Xia, YUE Xiao-Kui, LOU Yun-Feng
    2011, 31 (5):  25-30.  doi: 10.3780/j.issn.1000-758X.2011.05.004
    Abstract ( 1733 )   PDF (339KB) ( 1782 )   Save
    The two point boundary value problem (TPBVP) of a leader-follower spacecraft formation flying was studied. Aiming at unperturbed elliptical reference orbits, the state transfer matrix representing actual relative position and velocity was derived, and the first-order analytical solution of TPBVP is obtained, which can deal with the problems of the specified rendezvous time, fuel optimization and compromise between fuel and time, and is applicable to the periodic and non-periodic relative motion. The simulation results show that the normalized accuracy of this solution achieves 10-6 level. Furthermore, the fuel cost of relative transfer increases with eccentricity increasing, and decreases with semimajor axis increasing, and appears periodic change with initial true anomaly increasing, and decreases as the transfer time increasing.
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    Review on Integral Stiffened Shell Structure Technology of Large Space Station
    YU Deng-Yun, LAI Song-Bai, CHEN Tong-Xiang
    2011, 31 (5):  31-40.  doi: 10.3780/j.issn.1000-758X.2011.05.005
    Abstract ( 1768 )   PDF (891KB) ( 1918 )   Save
    A survey of integral stiffened shell technology was carried out, and the structural design, materials, manufacturing, bending forming technology of integral stiffened shell together with their development trends were analyzed. With regard to the research status of relevant technology in China,difficulties and obstacles of  the engineering development of space station integral stiffened shell were pointed out, and research suggestions were also given.
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    Vision-aided Attitude Determination for Air-bearing Simulator of Rendezvous and Docking
    WEI Xi-Qing, SONG Shen-Min
    2011, 31 (5):  41-47.  doi: 10.3780/j.issn.1000-758X.2011.05.006
    Abstract ( 1873 )   PDF (403KB) ( 1573 )   Save
    Firstly,the simulator was introduced to simulate the procedure of spacecraft rendezvous and docking. Then, attitude kinematics and pose from orthography and scaling with iterations (POSIT) algorithms were described. Secondly, extended Kalman filter(EKF) was used to integrate the data from two sensors so as to determine the relative attitude and gyro biases.  Thirdly, a nonlinear observer was presented to overcome the difficulty of tuning the parameters of EKF and avoid solving the inverse of matrix during EKF updating. Finally, experiments were carried out upon 4-DOF air-bearing simulators. The experimental results validate the availability and precision of the proposed methods. 
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    Relative Guidance Accuracy Analysis for Non-cooperative Space Target by Range-only Measurement of Satellite Formation
    SU Jian-Min, DONG Yun-Feng
    2011, 31 (5):  48-56.  doi: 10.3780/j.issn.1000-758X.2011.05.007
    Abstract ( 2019 )   PDF (398KB) ( 1656 )   Save
    Relative motion states of non-cooperative space target cannot be fully estimated by single satellite range-only measurement. To solve this problem, formation satellites range-only measurement was proposed. System model and measurement model were established. System observability matrix was derived, and the degree of observability was calculated. Relative motion states of non-cooperative space target were estimated through unscented Kalman filter (UKF). Analyses and simulations show that all relative motion states of non-cooperative space target can be estimated by using two-satellite range-only measurement data. The larger the angle of measurement vectors is,  the more accurate the states estimation is. When formation size is far less than the distance of target, more than two measurement satellites cannot improve states estimation accuracy.
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    Optimal Analysis of the Reliability for Torsion Spring Based on Multi-failure Modes
    WANG Mei, CHEN Guo-Ding, XIAO Yong
    2011, 31 (5):  57-63.  doi: 10.3780/j.issn.1000-758X.2011.05.008
    Abstract ( 1884 )   PDF (361KB) ( 1139 )   Save
    Based on the general stress intensity distribution of a broad interference theory and reliability model of a single failure mode, the torsion spring reliability optimization model was established under multi-failure mode. The normalized weighted method was used to solve the torsion spring reliability calculation under equal failure effect mode and unequal failure effect mode. Under given structure and constraint conditions of torsion spring, the best reliability optimization of torsion spring structure was done in the same failure mode (equal failure effect) and different failure mode (unequal failure effect) one using the proposed model and techniques. Under equal failure effect and unequal failure effect, compared with the torsion spring reliability of non-optimized structure, the proposed reliability optimization models and methods proposed are reliable, valid and good reference for the reliability optimization of the spacecraft components.
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    Selection of the Beacon Pulsars in Pulsars Navigation
    CHU Yong-Hui, WANG Da-Yi, HUANG Xiang-Yu
    2011, 31 (5):  64-69.  doi: 10.3780./j.issn.1000-758X.2011.05.009
    Abstract ( 1853 )   PDF (333KB) ( 1167 )   Save
    The analysis of X-ray pulsars principle shows that the beacon pulsars position and measurement error directly affect the navigation performance. To select the best beacon pulsars group, a selection method was developed based on the error covariance analysis. This method defines the criteria of PDOP (Positioning Dilution of Precision)and PSC (Pulsars Select Criteria), considering the effect of pulsars distribution and the measurement errors. Taking the circle phase of the Mars as an example, the method is validated through numerical simulation.
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    Soft Landing Impact Simulation of Lunar Lander
    LIN Qing, NIE Hong, CHEN Jin-Bao, WAN Jun-Lin, LI Li-Chun
    2011, 31 (5):  70-75.  doi: 10.3780/j.issn.1000-758X.2011.05.010
    Abstract ( 2221 )   PDF (453KB) ( 1992 )   Save
    To improve the analysis accuracy of soft landing impact response for lunar lander, a method based on nonlinear transient dynamic analysis was presented. In view of the influence of the flexibility of lunar lander and regolith on impact response of payloads, the flexible models for the lander and regolith were built by MSC.PATRAN based on a certain lunar lander. Then, the transient dynamics software MSC.DYTRAN was used to simulate the payloads impact response of soft landing. It shows that the simulation is consistent with experimental results. The proposed method analyzes the landing impact response for several payloads accurately and simulates the actual landing conditions of lunar lander realistically.
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    Shape Optimization Design and Simulation of Near Space Airship
    YANG Yan-Chu, WANG Sheng, GU Yi-Dong, LI Ying-Tang, MIAO Jing-Gang
    2011, 31 (5):  76-83.  doi: 10.3780/j.issn.1000-758X.2011.05.011
    Abstract ( 1735 )   PDF (378KB) ( 1598 )   Save
    A new multidisciplinary design optimization(MDO) method based on genetic algorithm was developed. The theoretic framework was built and an optimization program was designed. Firstly, genetic algorithm and MDO method were studied, and the resistance model, volume suface  ratio model, stress model were built, and the MDO method integrating aerodynamics, structure, and strength was introduced. Secondly, the genetic algorithm was used to optimize the airship shape which concluded a composite objective function, and a co-simulation method was carried out by the Matlab and Fluent. Finally, a practical case was provided and the feasibility of the method was demonstrated.
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