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Qi X.,Northwestern Polytechnical University | Shi Z.,North General Electronics Group Co Ltd | Zhu H.,Northwestern Polytechnical University
2013 9th Asian Control Conference, ASCC 2013 | Year: 2013

Attitude determination is strongly coupled with the estimation of unknown vibration parameters when the output of the inertial measurement unit (IMU) is corrupted by the vibration induced by the piston engine. The unknown vibration parameters in the attitude dynamics can degrade attitude accuracy of dead reckoning. In this paper, a dual estimation of attitude and parameters considering vibration is investigated for small UAV. The dynamic model contained attitude and parameters is established by state augmentation, and the observations are chosen as GPS velocity and heading. In order to employ hybrid extended kalman filter for dual estimation, Jacobian matrixes are formulated by linearizing the estimation model to propagate and update error variance. Since joint state estimation has tremendous computational loads, based on matrix blocking a state and parameter separated estimation is proposed to decouple the estimation of attitude and parameters. Simulation results show that the proposed method can give high precision attitude than the common filter without considering vibration. © 2013 IEEE. Source

Gou Y.,Xidian University | Zhang S.,North General Electronics Group Co Ltd | Chen G.,Xidian University
Jixie Gongcheng Xuebao/Journal of Mechanical Engineering | Year: 2015

Multistable mechanisms can stay at multiple stable equilibrium positions without power input, and get more and more widely use in many regions. Fully compliant multistable mechanisms have some advantages such as free of assembly, frictionless, lower power consumption, and so on, but they are difficult to design because of the stress concentration and nonlinear characteristics caused by the large deformation of the flexible segments. A design approach is presented for a type of fully compliant sexastable mechanism, which possesses six stable equilibrium positions, employing a compliant structure and two compliant bistable mechanisms with different snap-through forces. The model of the compliant structure is built by pseudo-rigid-body model to achieve the force-deflection characteristics. The force-deflection curves of the two components are compared to obtain the stability criterion for the sexastable mechanism, avoiding nonlinear analysis. Formulas are proposed to determine the stiffness arrange of the flexible segments of the compliant structure, which is the basis of the size parameters design for the flexible segments. A design example is given and the finite element analysis by ANSYS software and the prototype test prove the feasibility of this design approach. ©, 2015, Editorial Office of Chinese Journal of Mechanical Engineering. All right reserved. Source

Chai R.-X.,Xian Jiaotong University | Guo C.,Xian Jiaotong University | Yu L.,North General Electronics Group Co Ltd
Materials Science and Engineering A | Year: 2012

Arrhenius-type constitutive equation considering strain compensation and BP neural network model are used to analyze the hot deformation behavior of XC45 steel. The experimental data are acquired from hot compression tests in Gleeble-1500 thermal-mechanical simulator in the range of temperature from 1053K to 1253K and strain rates from 0.01s -1 to 10s -1. The predictabilities of Arrhenius-type constitutive model and back propagation (BP) neural network model can be evaluated based on the correlation coefficient (R), root mean square error (RMSE) and average absolute relative error (AARE), and their predictabilities can be compared through several verification methods. It can be found that the BP neural network model is better in the predictable ability than the Arrhenius-type constitutive model. © 2011 Elsevier B.V. Source

Wang S.,PLA Air Force Aviation University | Song S.,North General Electronics Group Co Ltd | Huang J.,North General Electronics Group Co Ltd
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

Improvement factor of bistatic radar suffers from the time and frequency synchronization, this is analyzed firstly in this paper. And then we design a field system which can fulfill the improvement factor measurement for bistatic radar. © 2012 Springer-Verlag. Source

Li X.-P.,North General Electronics Group Co Ltd | Li X.-P.,Xidian University | Zhang S.-H.,Northwestern Polytechnical University | Yang Y.-B.,North General Electronics Group Co Ltd | Li Z.-Y.,Xian Institute of Applied Optics
2012 International Conference on Microwave and Millimeter Wave Technology, ICMMT 2012 - Proceedings | Year: 2012

In this paper, the design of a W-band slotted waveguide antenna array developed recently on the background of millimeter mave missle-borne radar seeker is introduced. The emphasis of this research is on combing electromagnetism design with thermal-analysis technology, presents a practical method of describes a way how to design W-band missle-borne antenna array and improve the performance of the array efficiently. To verify the effectiveness of this method, a W-band slotted waveguide antenna array was successfully simulated, fabricated and measured. The results of numerical simulation and experimental measurement for the proposed array show that the simulated data are approximately consistent with the measured ones in the desired W-band. Additionally, by the technology of thermal analysis based on simulated software, the influence of the working temperature on the property of the material and designed array was also deeply studied. © 2012 IEEE. Source

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