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Liu Y.-N.,Beijing Institute of Technology | Xu M.-M.,Beijing Institute of Technology | Pan X.-M.,Beijing Institute of Technology | Sheng X.-Q.,Beijing Institute of Technology | Jin C.-J.,Science and Technology on Space System Simulation Laboratory
IEEE Antennas and Propagation Society, AP-S International Symposium (Digest) | Year: 2015

The direct solver based on skeletonization consists of two stages: selecting skeletons and computing the inverse matrix. The selection of skeletons can be expensive although Huygens' principle is employed to avoid filling in the complete impedance matrix. A fast matrix filling strategy is proposed to alleviate the difficulty by making use of Taylor series. Numerical experiments indicate the proposed method can significantly accelerate the matrix filling process with no loss in accuracy. © 2015 IEEE. Source


Sun L.,Beihang University | Wang W.,Beihang University | Zhang W.,Science and Technology on Space System Simulation Laboratory
Proceedings of the 2012 24th Chinese Control and Decision Conference, CCDC 2012 | Year: 2012

This paper contraposes issues related to modeling and control for swing nozzle, uses the methods of modeling and analysis, elaborates the research on fuzzy PID robust control for swing nozzle. In addition, swing nozzle servo system installation and other related issues, the influence of load torque and the analysis of the related processing on the swing nozzle are given. The computer simulation results show that the control scheme proposed in this paper fuzzy PID robust control can achieve a good result for swing nozzle servo system. © 2012 IEEE. Source


Cai C.,Beihang University | Wang W.-H.,Beihang University | Zhang W.-L.,Science and Technology on Space System Simulation Laboratory
26th Chinese Control and Decision Conference, CCDC 2014 | Year: 2014

As for parameters fluctuating, uncertainties caused by external disturbance and friction, the nonlinearity of the flight simulator turntable servo system, a discrete model reference sliding mode control theme combining with adaptive method and decoupled disturbance compensator is presented, and the globally asymptotically stability of the system is proved. The simulation results verified that the proposed control method can restrain the uncertainties and external disturbance of the flight simulator servo system efficiently assuring the dynamic tracking performance and strong robustness at a long range frequency. © 2014 IEEE. Source


Wu Y.,Beihang University | Liu B.,Science and Technology on Space System Simulation Laboratory | Zhang W.,Science and Technology on Space System Simulation Laboratory | Liu X.,Beihang University
International Journal of Modeling, Simulation, and Scientific Computing | Year: 2013

For flight simulator system, a kind of Adaptive Backstepping Sliding Mode Controller (ABSMC) based on Radial Base Function Neural Network (RBFNN) observer is presented. The sliding mode control theory is famous by its characteristic that it is insensitive to the external disturbances and parameters uncertainties. Combining this characteristic with Backstepping method can simplifies the controller design. And the addition of the terminal attractor can make the arrival time shorten greatly. However, too large external disturbances and parameters uncertainties are still not allowed to the system, and the design process of ABSMC does not have the upper bound information of disturbance until a RBFNN observer is designed to solve the problems. The simulation results show that the proposed scheme can improve the tracking precision and reduce the chattering of the control input, and the system has a higher robustness. © 2013 World Scientific Publishing Company. Source


Qu Q.-Y.,Beijing Institute of Technology | Guo K.-Y.,Beijing Institute of Technology | Sheng X.-Q.,Beijing Institute of Technology | Ma J.,Science and Technology on Space System Simulation Laboratory | And 2 more authors.
IEEE Antennas and Propagation Society, AP-S International Symposium (Digest) | Year: 2015

The scattering centers induced by creeping waves on cone-shaped targets are studied. Because of separated transmitters and receivers, the scattering centers could be observed in bistatic mode, especially under situation of large bistatic angles. Although induced by the same scattering mechanism, i.e., creeping waves, scattering centers on different profiles of cone-shaped targets have distinguished attributes. Attributes of scattering centers have been analyzed theoretically based on geometrical theory of diffraction, and investigated numerically by time-frequency representation of scattered signals. © 2015 IEEE. Source

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