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Xi X.,National University of Defense Technology | Wu Y.,National University of Defense Technology | Wu X.,National University of Defense Technology | Tao Y.,National University of Defense Technology | Tao Y.,Wuhan Ordnance Nco Academy
Sensors and Actuators, A: Physical | Year: 2013

Trimming of resonators is an important process to improve the performance of the cupped gyroscopes. However, it may cause uneven thermal stress which destroys the stability of frequency split and mode shape. Though frequency splits can be reduced to the same degree by trimming at different positions of the resonator, the thermal stresses caused by varying temperatures are significantly different. In this paper, the stress effects of trimmed cupped resonators considering the influence of temperature are studied. The dynamical behavior of the cupped resonators at various temperatures is presented. The stress effects of trimmed resonators due to temperature variation are analyzed based on FE model. Simulation results show that under the same conditions, the bottom trimming gives rise to much more thermal stress than suspension trimming and ring trimming. In addition, a trimming method based on adding mass is studied. Finally, experiments were set up to validate the stress effect by using vibration measurement equipments and frequency analysis equipments. Experimental results show that with reference to the temperature variation the bottom trimming affects the frequency split and the mode deflection of the cupped resonator significantly. © 2012 Elsevier B.V. Source


Zhu B.,National University of Defense Technology | Tao Y.,National University of Defense Technology | Tao Y.,Wuhan Ordnance Nco Academy | Wu Y.,National University of Defense Technology | Chen Z.,National University of Defense Technology
Chinese Journal of Sensors and Actuators | Year: 2011

Focused on the bonding of the piezoelectric ceramic of the cupped gyro,we established a finite element model of base-layer-piezoelectric laminate film,the model was simulated and analyzed by Ansys,and the analysis was tested by experiments. The Q-factor, output gain and frequency of cleavage of resonator which were effected by the thickness of adhesive layer,material properties and defects in adhesive layer were detailedly analyzed. It is shown that the adhesive layer has little effect on the resonator frequency,but great effect on the resonator vibration characteristics. Reducing the thickness of the adhesive layer,enhancing the hardness of the adhesive layer under a certain range of elastic modulus can improve the resonator vibration characteristics,at the same time,we have explored how to improve the shear resistance of the adhesive layer. The research work provides reference to improve the performance of the cupped gyro. Source


Yu H.,Wuhan Ordnance Nco Academy | Zhao D.,Shijiazhuang Mechanical Engineering College
Proceedings - 2011 7th International Conference on Natural Computation, ICNC 2011 | Year: 2011

For multi-LEO combined orbit determination (COD) satellite-network based on space-based tracking telemetry and command (STTC) satellites, kinematic orbit information can be obtained only using the method of precise point positioning (PPP) based on observation models, but the orbits results are not very precise because of the precision of observation data and the Geometry Dilution of Precision (GDOP) of STTC constellation. If kinematic orbit information of low earth orbit (LEO) satellite-network can be taken full advantage of participating in dynamic precise orbit determination (POD) and making them achieve best matching, namely integrative COD models based on kinematic and dynamic information are brought forward in this paper to realize dynamic smoothness of kinematic orbit information, which hopefully can be gained more perfect COD precision of LEO satellite-network. Firstly, single LEO kinematic method based on difference positioning model and the corresponding algorithm was designed, and integrative COD models of COD satellite-network were constituted based on kinematic orbit information of PPP method and dynamic trajectory information. Then integrative COD fusion models based on prior trajectory information were established, and the optimal weighting algorithm of multi-structural nonlinear COD models based on extended prior information was designed. Theoretical analysis and simulation computation results show that COD weighting method based on prior trajectory information can realize LEOs dynamic information optimal matching with kinematic prior information, and can restrain nonlinear influence factor including measure models errors and ephemeris errors to the effects of POD precision by considering models errors modeling and dynamic models sparse parameters denotation, which further ameliorate COD precision of STTC satellite constellation and LEOs. © 2011 IEEE. Source


Zhao D.,Shijiazhuang Mechanical Engineering College | Yu H.,Wuhan Ordnance Nco Academy
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

For multi-LEO combined orbit determination (COD) satellite-network based on space-based tracking telemetry and command (STTC) satellites, kinematic orbit information can be obtained only using the method of precise point positioning (PPP) based on observation models, but the orbits results are not very precise because that the precision of observation data and the Geometry Dilution of Precision (GDOP) of STTC constellation cannot meet the demands of high precision application requirements of LEOs. The high precision denotation model of satellite orbit dynamics based on physics parameter model and mathematics model which associates sparse parameter representation with time sequence analysis, nonlinear semi-parametric combined observation model based on system error parameters modeling and non-parametric component denotation of model error, and COD parameterized fusion model are established aiming at multi-satellite high precision COD based on bi-satellite positioning system and low earth orbiters (LEOs). Then parameters estimation algorithms of the former two kinds of models and the combined estimation algorithm of parameterized fusion model are designed. Theoretic analysis and simulated computation results show that the high precision denotation method of sparse parameters model and the optimized modeling method of observation model considering model error can improve modeling precision, and combined estimation algorithm of parameterized fusion model can synchronously ameliorate orbit determination precision ulteriorly. © 2011 Springer-Verlag. Source


Zhang L.,Academy of Equipment Command and Technology | Sun H.,Academy of Equipment Command and Technology | Xu J.,Wuhan Ordnance Nco Academy
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

The laser atmosphere transmission characteristic affects the use of laser in engineering greatly. This paper designed a laser atmosphere transmission characteristic measurement system based on LabVIEW software, a product of NI. The system acquires laser spacial distribution by means of controlling NI image acquisition card and CCD through PCI, controls oscillograph to acquire laser time domain distribution through Ethernet and controls power meter to acquire energy of laser through RS-232. It processes the data acquired and analyses the laser atmosphere transmission characteristic using Matlab, which is powerful in data processing, through software interface. It provided a new way to study the laser atmosphere transmission characteristic. © 2010 SPIE. Source

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