中国科学院机构知识库网格系统: 检索

Structural design and simulation analysis of ejector used in automotive power steering oil discharge equipment (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Mechanical Engineering, Materials Science and Civil Engineering, ICMEMSCE 2012, August 18, 2012 - August 20, 2012, Harbin, China
Cheng K.; Zou H.; Kong X.; Tang J.

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The structure of ejector used in automotive power steering oil discharge equipment is designed in accordance with the theory of gas-liquid ejector.The two important parameters of the ejector are elected respectively to five values and then 25 ejector models are obtained by the permutations and combinations.The ejector's CFD model is created by Fluent module of Ansys then it is divided into a grid and analyzed. Analyse its pressure distribution and velocity vector which provides the optimal size for the manufacture of the ejectors and a theoretical basis for experiment. (2013) Trans Tech Publications Switzerland.

Longitudinal control law design and simulation of fixed-wing UAV (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Measurement, Instrumentation and Automation, ICMIA 2012, September 15, 2012 - September 16, 2012, Guangzhou, China
作者: Duan Z.

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Taken some fixed-wing UAV as the study object the aircraft movement was broken down into the longitudinal movement and lateral movement according to the linearized small perturbation principle the longitudinal control law design method was discussed using root locus which belonged to classical control theory. The six degrees of freedom nonlinear model simulation result shows that: the control parameters designed are reasonable the simulation profile is fully consistent with the setting profile the control effect of pitch angle loop and altitude loop meets with the indices requirements the method is mature and reliable easy to realize in engineering. (2013) Trans Tech Publications Switzerland.

Advanced astigmatism-corrected tandem Wadsworth mounting for small-scale spectral broadband imaging spectrometer (EI CONFERENCE) 会议论文 OAI收割
作者: Lin G.-Y.

收藏 | 浏览/下载：35/0 | 提交时间：2013/03/25

Tandem gratings of double-dispersion mount make it possible to design an imaging spectrometer for the weak light observation with high spatial resolution high spectral resolution and high optical transmission efficiency. The traditional tandem Wadsworth mounting is originally designed to match the coaxial telescope and large-scale imaging spectrometer. When it is used to connect the off-axis telescope such as off-axis parabolic mirror it presents lower imaging quality than to connect the coaxial telescope. It may also introduce interference among the detector and the optical elements as it is applied to the short focal length and small-scale spectrometer in a close volume by satellite. An advanced tandem Wadsworth mounting has been investigated to deal with the situation. The Wadsworth astigmatism-corrected mounting condition for which is expressed as the distance between the second concave grating and the imaging plane is calculated. Then the optimum arrangement for the first plane grating and the second concave grating which make the anterior Wadsworth condition fulfilling each wavelength is analyzed by the geometric and first order differential calculation. These two arrangements comprise the advanced Wadsworth mounting condition. The spectral resolution has also been calculated by these conditions. An example designed by the optimum theory proves that the advanced tandem Wadsworth mounting performs excellently in spectral broadband. 2012 Optical Society of America.

Stray light analysis of solar photoelectric detection system on space target (EI CONFERENCE) 会议论文 OAI收割
2012 International Conference on Intelligent System and Applied Material, GSAM 2012, January 13, 2012 - January 15, 2012, Taiyuan, Shanxi, China
Li L.-Y.; Wang Y.-F.; San X.-G.

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Most conventional spacious solar photoelectric detection systems suffer from unexpected stray light. This paper demonstrates the effects on photoelectric detection system bring out by stray light. On this foundation build up evaluation index of stray light system to search the reasonable programme to eliminating stray light. A detailed telescope system geometry model was created and scatter models were create for telescope and enclosure components. By the means of designing the structure of main baffle baffle vane and the coating technology. In order to verify the prosperity of structure that designed we utilizes software to analysis opto-mechanical model. we utilizes software to analysis opto-mechanical model. The simulations show that point source transmittance of the system is thus reduced by up to two orders of magnitude between 10-8 and 10-10. Meanwhile the experiment obtains clean detection data which satisfies the system requirements. Stray light has been suppressed effectually and so measurement precision was improved from detection graphics. (2012) Trans Tech Publications.

Retrieval of snow depth in Northeast China using FY-3B/MWRI passive microwave remote sensing data (EI CONFERENCE) 会议论文 OAI收割
Satellite Data Compression, Communications, and Processing VIII, August 12, 2012 - August 13, 2012, San Diego, CA, United states
Ren R.; Gu L.; Chen H.; Cao J.

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Comparing with optical remote sensing techniques passive remote sensing data have been proved to be effective for observing snowpack parameters such as snow depth and snow water equivalent which can penetrate snowpack without clouds interferences. The Microwave Radiation Imager (MWRI) loaded on the Chinese FengYun-3B (FY-3B) satellite is gradually used in the global environment research through November 2011. In this paper we proposed a snow depth retrieval algorithm to estimate snow depth in Northeast China using MWRI passive microwave remote sensing data. A decision tree method of snow identification was firstly designed to distinguish different snow cover conditions in order to eliminate other interference signals. After using the proposed decision tree method the processing results were further used to retrieve the snow depth in Northeast China. Finally the practical snow depth data and the MODIS data were collected for the accuracy assessment of the proposed snow depth retrieval method. The experimental results demonstrated that the RMSE of snow depth used the proposed method was approximately 3 cm in Northeast China. 2012 SPIE.

All-solid-state high beam quality 1053nm nd: Glass amplifier at repetition frequency (EI CONFERENCE) 会议论文 OAI收割
2nd International Conference on Optical, Electronic Materials and Applications 2012, OEMA 2012, May 25, 2012 - May 26, 2012, Chongqing, China
作者: Qiu J.; Yu J.

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A laser amplifier of LD pumping Nd: glass with a high beam quality and stability which amplifies nanosecond laser pulse has been developed in this paper. The device adopts the major technology of "LD pumping multi pass amplification together". Beam transmission is designed with the technology of "inhibition of diffraction effect active control and spatial filtering". (2012) Trans Tech Publications Switzerland.

Research on satellite platform vibration compensation method based on liquid crystal steering system (EI CONFERENCE) 会议论文 OAI收割
2011 SSITE International Conference on Future Material Research and Industry Application, FMRIA 2011, December 1, 2011 - December 2, 2011, Macau, China
作者: Wen M.

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This paper presents the disturbance compensation scheme based on liquid crystal steering system according to the problem that satellite platform vibration affects the tracking and pointing accuracy in space optical communication. The mathematical model of liquid crystal steering system is built. For improving convergence speed the adaptive controller based on posteriori estimation errors RLS lattice filter is designed which not only achieves fast adaptation but also reaches optimal steady-state disturbance compensation. Finally the simulation results show that this control scheme is valid and feasible. (2012) Trans Tech Publications Switzerland.

Analysis of zenith pass problem and tracking strategy design for roll-pitch seeker (EI CONFERENCE) 会议论文 OAI收割
作者: Jiang H.

收藏 | 浏览/下载：17/0 | 提交时间：2013/03/25

Roll-pitch seeker is currently applied in particular missiles. There is a stubborn problem called zenith pass problem while roll-pitch seeker is used. Analysis of the zenith pass problem which always results in loss of target is presented in this paper. Based on the analysis result tracking strategy is carried out to deal with zenith pass problem. To prove the validity of tracking strategy a practical roll-pitch seeker was accomplished. Model identification and common PID controllers for the physical roll-pitch seeker are taken on after that both disadvantages derived from zenith pass problem in tracking process and meliorated phenomenons by the tracking strategy are shown. It is concluded that the tracking strategy designed for solving the zenith pass problem is efficient. 2011 Elsevier Masson SAS. All rights reserved.

Research on satellite platform vibration compensation technology for space optical communication (EI CONFERENCE) 会议论文 OAI收割
2012 International Meeting on Opto-Electronics Engineering and Materials Research, OEMR 2012, July 27, 2012 - July 29, 2012, Shenyang, Liaoning, China
Han C.; Li X.

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The piezo-electric steering control system is used to compensate the vibration of satellite platform. The mathematical model of piezo-electric steering system is built. The adaptive controller based on improved LMS filter algorithm is designed according to this system characteristic. The adaptive delay filter is designed to solve slow convergence speed problem of traditional algorithm. Meanwhile the adaptive delay filter can also compensate phase delay of control circuit. The adaptive deviation filter is introduced and it effectively compensates the vibration deviation which is low frequency and high amplitude. The experimental results show that the remained errors are rad which meets space optical communication requirement and proves that this control scheme is valid and feasible. (2012) Trans Tech Publications Switzerland.

Trajectory tracking control of a quad-rotor UAV based on command filtered backstepping (EI CONFERENCE) 会议论文 OAI收割
2012 3rd International Conference on Intelligent Control and Information Processing, ICICIP 2012, July 15, 2012 - July 17, 2012, Dalian, China
Gong X.; Bai Y.; Peng C.; Zhao C.; Tian Y.

收藏 | 浏览/下载：30/0 | 提交时间：2013/03/25

A quad-rotor unmanned aerial vehicle is an under-actuated strong coupled nonlinear system with parameters uncertainty and unknown external aerodynamic disturbance. The trajectory tracking control system with a nested double-loops structure is designed in this paper according to the coupling characteristic between the attitude angles and translational position. A PD control algorithm is proposed in the translational outer-loop to export the desired attitude signals to the attitude inner-loop. An adaptive backstepping control algorithm is designed in the inner-loop with respect to the uncertain rotational inertia and un-modeled disturbance while in order to reduce the computational complexity the command filtered approach is introduced into the designing procedure. And finally the numerical simulation results are presented for the trajectory tracking stabilization of a Quad-rotor which demonstrates the excellent performance of the proposed control system and illustrate its robustness in face of disturbance and uncertain parameters. 2012 IEEE.