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25 August 2013, Volume 33 Issue 4 Previous Issue    Next Issue

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Robust Control of Spacecraft Attitude Based on Fractional Order Sliding-mode Controller DENG Li-Wei, SONG Shen-Min 2013, 33 (4):  1-8.  doi: 10.3780/j.issn.1000-758X.2013.04.001 Abstract ( 1595 )   PDF (405KB) ( 1421 )   Save To deal with the high precision and high stability attitude control problem of a spacecraft model with external disturbances and inertia uncertainties, a new strong robust fractional sliding model controller was proposed. Firstly, based on the mathematical model of the spacecraft described with the modified Rodrigues parameters, an equivalent mathematical model was deduced, which was convenient for the design of the fractional sliding mode controller. Secondly, the fractional differential operator with rapid convergence performance and good information memory ability was introduced into the sliding surface and control law, and a fractional sliding mode controller was proposed. The entire system stability was proved with the Lyapunov theory and the fractional-order stability theory. Finally, numerical simulations demonstrate the high stability, strong robustness and excellent interference resistance ability of the fractional sliding mode controller. Related Articles | Metrics

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Study on On-orbit Calibration of Center of Mass for Gravity Satellite XIN Ning, QIU Le-De, ZHANG Li-Hua, DING Yan-Wei, WANG Da-Lei 2013, 33 (4):  9-15.  doi: 10.3780/j.issn.1000-758X.2013.04.002 Abstract ( 1657 )   PDF (398KB) ( 945 )   Save A method for on-orbit calibration of center of mass for gravity satellite was proposed， based on a predictive filter fusing extended Kalman filter estimation algorithm．Firstly，a periodic magnetic torque which was more larger than other external torques was applied to the satellite．Secondly，the observation of gyro was used to estimate angular acceleration based on the predictive filter．Finally，an extended Kalman filter was used to estimate the satellite′s center of mass．The numerical results indicate that the angular acceleration and center of mass can be real-time estimated. The calibration accuracy of three axes is [0.0628 0.0324 0.0414] mm, which demonstrates the effectiveness of the proposed method． Related Articles | Metrics

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Selection of the Measurement Model for Line-of-sight Observation Based Optical Navigation System LI Jian-Guo, CUI Hu-Tao, TIAN Yang 2013, 33 (4):  16-23.  doi: 10.3780/j.issn.1000-758X.2013.04.003 Abstract ( 1490 )   PDF (470KB) ( 890 )   Save In the autonomous optical navigation system based on line-of-sight vector observation, the nonlinearity of measurement model is an importance factor which influences the navigation accuracy. By quantitatively calculating the degree of nonlinearity, the selection of measurement model for line-of-sight observation based optical navigation system was studied. First, navigation measurement equations and measurement noise statistics of two line-of-sight measurement models were proposed based on the perspective projection colinearity equations. Next, the effects of measurement model nonlinearity on the navigation performance were thoroughly analyzed within the framework of the extended Kalman filter. Then, the measures of nonlinearity of two measurement models using the differential geometry curvature nonlinearity measure theory were compared. Finally, the simulation of attitude determination system from vector measurement was performed to confirm the proposed theory. The results show that the curvature nonlinearity measure magnitude and the filter performance are consistent and the optical navigation system based on the unit vector measurement model has higher precision and faster convergence properties than that based on the focal plane model. Related Articles | Metrics

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Correction Method for Transient Thermal Analysis Model of Small Satellite ZHANG Jing-Yang, CHANG Hai-Ping, WANG Li-Guo 2013, 33 (4):  24-30.  doi: 10.3780/j.issn.1000-758X.2013.04.004 Abstract ( 1573 )   PDF (438KB) ( 889 )   Save The susceptibilities of the time-average and fluctuation quantity of revising parameters was defined, and the mean square deviation of transient temperature between analysis and experiment values were built, so that the expression about time domain process of transient temperature was solved in parameter classification and the building of the minimum error target function. The sensitive parameters were corrected by the means of Monte-Carlo mixed method according to the classification layer by layer. The correction result shows that the transient temperature error is reduced from 8%~16% to less than 5%, and the time-average and fluctuation quantities are improved obviously. Moreover, the conclusion is proved by the experiment data which is not utilized in the correction process. It indicates the proposed method about transient temperature and Monte-Carlo mixed correction method according to the classification layer by layer in correction process is rational with improved transient thermal analysis accuracy. Related Articles | Metrics

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Disturbance Observer Based Exponential Time-varying Sliding Mode for Re-entry Attitude Control WANG Liang, LIU Xiang-Dong, SHENG Yong-Zhi, CONG Bing-Long 2013, 33 (4):  31-39.  doi: 10.3780/j.issn.1000-758X.2013.04.005 Abstract ( 1443 )   PDF (445KB) ( 896 )   Save For re-entry vehicle attitude control problem, a disturbance observer-based exponential time-varying sliding mode attitude controller was designed to achieve precise attitude control when the matched parametric uncertainties and external disturbances occured. Firstly, feedback linearization method was applied to the nonlinear model of re-entry vehicle, which decomposed the pitch, roll and yaw channel decomposed into three independent second order system. Then, as an example, an exponential time-varying sliding mode controller (ETVSMC) was designed for the pitch channel. Furthermore, to reduce the static error caused by boundary layer solution which was used to soften the chattering, a disturbance observer based exponential time-varying sliding mode control (DOETVSMC) method was presented. Finally, a six degree-of-freedom simulation mode was established for a re-entry vehicle considering the atmospheric density, inertial uncertainties and external high-frequency perturbations, to demonstrate the improved performance of DOETVSMC with ETVSMC. Related Articles | Metrics

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Reduction of Gravitational Attraction Disturbance to Purely Gravitational Orbit Based on Satellite Spinning GU Zhen-Feng, WANG Zhao-Kui, ZHANG Yu-Lin 2013, 33 (4):  40-46.  doi: 10.3780/j.issn.1000-758X.2013.04.006 Abstract ( 1874 )   PDF (394KB) ( 1181 )   Save An inner satellite which is a proof mass freely flying in the shield cavity of the outer satellite does not suffer the external disturbances, such as air drag and solar pressure, and follows a purely gravitational orbit. The gravitational attraction on the inner satellite due to the outer satellite is a significant disturbance source to the purely gravitational orbit. The analysis model was deduced from the relative motion equation of formation flying to calculate the effect of gravitational attraction to purely gravitational orbit. With the outer satellite spinning to modulate the gravitational attraction, the function of reducing the effect of gravitational attraction was analyzed. It indicates that spinning of the outer satellite can evidently reduce the long-period effect of gravitational attraction disturbance. The departures of the inner satellite from the purely gravitational orbit due to the gravitational attraction were calculated for the Inner Formation Flying System with the outer satellite spinning or not. The comparison shows that the days departure can be reduced by about five to seven orders of magnitude if the outer satellite is rotated. Related Articles | Metrics

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Configuration Parameter Design for ADAM-type Articulated Mast Based on Maximizing Specific Stiffness LI Biao, CHENG Gang, LIU Zhi-Quan, DING Feng 2013, 33 (4):  47-54.  doi: 10.3780/j.issn.1000-758X.2013.04.007 Abstract ( 1623 )   PDF (451KB) ( 1297 )   Save The performances of the ADAM-type mast, such as mass, packaging size, stiffness and strength, are determined by its configuration parameters. A new design of configuration parameters based on maximizing specific stiffness was presented. By MATLAB and ANSYS joint simulation，the varying of specific stiffness with different configuration parameters was analyzed. The simulation results show that the optimum value of the length ratio of longeron to batten and the canister radius increases with the increase of the length of mast, when the length of ADAM-type varies in the range of 20 to 100 meters. While the length of mast is 20, 60, and 100 meters, the optimum value of the canister radius varies from 0.3 to 0.4 meter, 0.5 to 0.7 meter and 0.6 to 0.9 meter respectively. The design flow of configuration parameter based on maximizing specific stiffness is as follow: the canister radius is settled at first, then the length ratio of longeron to batten should be determined, and the number of longitudinal member could be finally settled. By this method, configuration parameters of the mast in the SRTM program are designed, and the results approximate to that of ADAM′s. Related Articles | Metrics

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High-rate Data Transmission Stream Design for Remote Sensing Satellite ZHU Hong, ZHENG Xiao-Song, HUANG Pu-Ming 2013, 33 (4):  55-61.  doi: 10.3780/j.issn.1000-758X.2013.04.008 Abstract ( 1767 )   PDF (471KB) ( 1370 )   Save With the development of satellite remote sensing technology, type and amount of remote sensing data are increasing rapidly. In order to meet the complex needs of multi-type data and high rate remote sensing data transmission, a top-level design of the data transmission stream was presented, and both remote sensing/data transmission system data interface and data transmission frame format were defined, then a classified calculation of transmission rate required for remote sensing data transmission was put forward to provide a prerequisite for the design of a fixed down-link data transmission rate. Then a data transmission stream design was proposed based on the virtual channel dynamic scheduling with subgroup priority to ensure that the transmission of different types of remote sensing data meet the requirements of different applications, in which the high-speed remote sensing data was processed with small cache capacity requirements while the low speed one was done to satisfy the real-time transmission demand. Dynamic simulation results demonstrate the correctness of the proposed scheme. The suggested approaches have a reference for design of the follow-up new generation remote sensing satellite data transmission system. Related Articles | Metrics

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COMPASS Satellites DCB Parameter Accuracy Assessment Based on Tri-frequency Data FAN Jia-Chen, WU Xiao-Li, LI Yu-Xiang, WEI Gang 2013, 33 (4):  62-70.  doi: 10.3780/j.issn.1000-758X.2013.04.009 Abstract ( 2426 )   PDF (564KB) ( 1897 )   Save As an important part of GNSS navigation message, the differential code bias (DCB) parameter is one of the main error sources affecting the PNT services. COMPASS provides navigation signals on three frequencies, and broadcasts two TGD parameters. An algorithm to solve COMPASS satellites DCB parameters and their form error was introduced. According to the COMPASS tri-frequency characteristics, a new method using different dual-frequency combinations was proposed to evaluate the accuracy of DCB parameters. DCBs provided by manufacturers and DCBs solved by the algorithm are taken to analyze the effects on UERE and positioning accuracy. Real data analysis indicates that the form error of COMPASS satellite DCBs and GPS satellite DCBs share the same accuracy, however, influenced by the satellite constellation and regional distribution of stations, the stability of COMPASS satellite DCBs is worse than that of GPS satellite DCBs from IGS. The accuracy of COMPASS satellite DCBs is better than 0.5ns, and the difference of VTEC between different calculations using two kinds of geometric free combinations is better than 0.6TECU. Compared with DCBs provided by manufacturers, dual-frequency user′s 3D positioning accuracy is improved from 13.80% to 47.42% by using DCBs from the algorithm. Related Articles | Metrics

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One Prediction Method for High-precision GPS Satellite Clock Error TAO Ting-Ye, GAO Fei, LI Xiao-Li 2013, 33 (4):  71-75.  doi: 10.3780/j.issn.1000-758X.2013.04.010 Abstract ( 1260 )   PDF (289KB) ( 958 )   Save In order to get clock products with high accuracy in real time, the rapid clock products were used to establish a short-term prediction model. First, the data batch was detrended by fitting and removing with polynomial. Then, the spectrum of residual after detrending was calculated with Fourier transformation. Thus, the modeling period and forecasting period can be confirmed with the periodic characteristics. After this, the RBF (Radial Basis Function) neural network was used to fit and forecast the clock errors. Since the RBF neural network was fit for nonlinear data modeling, this method can get better forecasting results after extracting linear trend and determining reasonable modeling data size. In fact, prediction results indicate that clock error products obtained by the proposed method are shown to have higher accuracy than the ultra-rapid products, and can satisfy decimeter accuracy positioning applications. Related Articles | Metrics

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Quantum Particle Swarms Optimizations Algorithm Based on Surrogate Model for the Application of Structural Optimization HE Xing-Xing, LIAO Ying, LI Zhi 2013, 33 (4):  76-82.  doi: 10.3780/j.issn.1000-758X.2013.04.011 Abstract ( 1441 )   PDF (461KB) ( 1330 )   Save The traditional optimization algorithms might fail to get the global optimal solution for high non-linear characteristics in engineering optimization of multi-structures. So the Quantum Particle Swarm Optimization (QPSO) algorithm was induced and the QPSO algorithm based on surrogated model was studied. The applications to the structural parameter optimization of the ring truss deployable antennas were carried out by the surrogated model of dynamic characters for ring truss deployable antennas. The results show that the computation efficiency of QPSO algorithm based on Kriging model is acceptable. The non-linear characteristics of the 1st natural frequency and maximum impulse response of the ring truss deployable antennas are remarkable. Then the computation accuracy is validated by comparing the solutions between the optimal result and the finite element result. It′s proved that QPSO algorithm based on Kriging model can be used to optimize the complicated structures in engineering design. Related Articles | Metrics