中国开放科研知识云: 检索

Reentry guidance based on parametric optimization (EI CONFERENCE) 会议论文
2012 International Conference on Mechatronics and Control Engineering, ICMCE 2012, November 29, 2012 - November 30, 2012, Guangzhou, China
Li D.

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This paper presents a parametric optimization approach to solve reentry guidance. Due to the various constraints imposed on the trajectory original guidance problem can be converted into an optimal control problem with a merit function to be minimized. Direct implementation of method of variation and is too complex to get a reasonable result while a numerical parametric optimization approach is feasible and efficient if we choose appropriate control variables as the optimization parameters and effective optimization algorithm. A simulation of the approach is performed to show its validity on reentry guidance problem: as the value of merit function converges to acceptable threshold all constraints are hold. (2013) Trans Tech Publications Switzerland.

Effect of design parameters on the reduction of top piston ring friction (EI CONFERENCE) 会议论文
2nd International Conference on Computer-Aided Design, Manufacturing, Modeling and Simulation, CDMMS 2012, September 21, 2012 - September 23, 2012, Chongqing, China
Wu B.; Zhang Z.; Wang P.

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In order to reduce ring-liner interface friction power loss this paper focuses on the structure parameters of the top ring and investigates how the value of those parameters will influence top ring-liner friction power loss and the minimum thickness of oil film at top ring-liner interface. A mixed lubrication model is developed to simulate the effect of varying design parameters on ring-liner friction. Case study shows that ring-liner friction power loss will be reduced with decreased axial ring height and barrel height. This study provides a theoretical basis for design the top ring with reduced friction power loss at ring-liner interface. (2013) Trans Tech Publications Switzerland.

Centroid localization algorithm based on bicubic interpolation gray square weighted (EI CONFERENCE) 会议论文
2012 3rd International Conference on Advances in Materials and Manufacturing Processes, ICAMMP 2012, December 22, 2012 - December 23, 2012, Beihai, China
Zhou J.; Chen X.-L.; Li S.-J.; Huang D.-Y.; Ma G.-Z.

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The 3D coordinates of measured point is embodied in 2D image coordinate of the optical characteristic point via the visual measurement system. Based on the gray square weighted centroid localization algorithm the paper presents bicubic interpolation gray square weighted centroid localization algorithm increases the number of effective pixels around the optical characteristic point imaging center and reduces noise error via the gray square weighted improves the imaging center location accuracy of optical characteristic point realizes the accurate location of the optical characteristic points. Results indicate application of the proposed algorithm to location the standard tolerance along the direction of x is 0.0022 Pixel the standard tolerance along the direction of y is 0.0023 Pixel compared with the others the standard tolerance is minimum and discrete to a lesser degree distancing ideal image point that is the proposed algorithm has higher location accuracy. The maximum tolerance along the direction of x is 0.008 Pixel the one along the direction of y is 0.007 Pixel compared with the other two algorithms the maximum tolerance is minimum.Results indicate that the stability of the proposed algorithm is better. (2013) Trans Tech Publications Switzerland.

Angle measurements with laser (EI CONFERENCE) 会议论文
2012 International Conference on Measurement, Instrumentation and Automation, ICMIA 2012, September 15, 2012 - September 16, 2012, Guangzhou, China
Wang Y.; Yan C.; Gao Z.

收藏 | 浏览/下载：131/0 | 提交时间：2013/03/25

Laser is widely used in angle measurements. This paper presents several frequently used methods of angle measurement that utilize laser including:autocollimation angle measurement angle measurement based on internal-reflection effect laser interference angle measurement angle measurement with ring laser and angle measurement with CCD. The principle actualities application situation superiority and defects of each method are discussed. (2013) Trans Tech Publications Switzerland.

LABTM control system based on FPGA (EI CONFERENCE) 会议论文
2nd International Conference on Mechatronics and Applied Mechanics, ICMAM 2012, December 8, 2012 - December 9, 2012, Taiwan
Li X. F.; Wang X. P.; Qi X. D.; Wang Y.; Yu P.

收藏 | 浏览/下载：139/0 | 提交时间：2013/03/25

This paper presents the digital PI control method for design and simulation of a high precision limited angle brushless torque motor control system in Field Programmable Gate Array device (FPGA). The direct drive structures which are widely applied in many servo control fields. Matlab Xilinx System GeneratorR toolbox based on Fixed-Point Arithmetic is used to design the digital PI controller using DSP architecture plot the responses of the control system and generate the VHDL source code. The control system model consists of a digital PI a real LABTM and a real absolute Inductosyn encoder to rpm and position blocks. Through loading generated codes in process of the simulation that built by the digital discrete model it is verified that the rising time of current loop is only 1.2ms and rate loop is 8ms overshoot is rarely 4.2%. Finally the comprehensive positioning accuracy of system can reach up to 5 arc sec and the rate jitter achieves 5% with the 4 arc sec accuracy absolute Inductosyn. (2013) Trans Tech Publications Switzerland.

Integrated optimization method for coupling parametrization design of complex space system (EI CONFERENCE) 会议论文
2012 3rd International Conference on System Science, Engineering Design and Manufacturing Informatization, ICSEM 2012, October 20, 2012 - October 21, 2012, Chengdu, China
Wen M.; Han C.-S.

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This paper investigates the problem of optimization method for coupling parametrization design of complex space system. The objective is to develop an integrated optimization framework to design complex space system. An improved collaborative optimization (ICO) strategy for complex design using hybrid optimization algorithm is proposed which associates genetic algorithm (GA) with tabu search (TS). A multi-objective function with penalty terms for the systemlevel optimization and a relax factor for the subsystem optimization are adopted which can avoid unsolvability or converging difficulty. The results demonstrate the applicability and effectiveness of the proposed design methodology. 2012 IEEE.

Stray light analysis of solar photoelectric detection system on space target (EI CONFERENCE) 会议论文
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.

收藏 | 浏览/下载：134/0 | 提交时间：2013/03/25

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.

Immersed nanospheres super-lithography for the fabrication of sub-70nm nanoholes with period below 700nm (EI CONFERENCE) 会议论文
2012 12th IEEE International Conference on Nanotechnology, NANO 2012, August 20, 2012 - August 23, 2012, Birmingham, United kingdom
Li S.; Shi L.; Yang Z.; Huang X.; Zhang Z.; Gao F.; Guo Y.; Yu W.; Du J.

收藏 | 浏览/下载：129/0 | 提交时间：2013/03/25

A maskless nano-lithography method by using polystyrene spheres (PSs) self-assembled on silver slab (NSSL) was proposed in [optics express Vol. 16 No. 19 (2008) 14397]. Following that to break the limitations in resolution and PSs period of NSSL method in this paper we present PSs immersed super-resolution lithography (NSISL) technology by embedding the PSs into appropriate material to improve the efficiency of the surface plasmon excitation. The energy modulating mechanism and the rules of the resolution affected by silver slab were studied by calculating and analysing the energy distribution. The curve of the lithography resolution versus the silver thickness was presented. In order to verify this method contrast analysis was carried out with NSSL. The results show that the lithography resolution is improved efficiently. Taking a specific configuration with PS diameter of 600nm as an example the resolution was improved to 54nm from 190nm with Ag thickness of 25nm. Based on the calculation results we carried out the experiments. Nano holes with dimension of 75nm and period of 600nm were obtained. 2012 IEEE.

Retrieval of snow depth in Northeast China using FY-3B/MWRI passive microwave remote sensing data (EI CONFERENCE) 会议论文
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.

The application of digital signal processing (DSP) for the real time solving of artillery fire control exterior trajectory (EI CONFERENCE) 会议论文
2012 IEEE 3rd International Conference on Software Engineering and Service Science, ICSESS 2012, June 22, 2012 - June 24, 2012, Beijing, China
Li D.; Guo L. H.

收藏 | 浏览/下载：131/0 | 提交时间：2013/03/25

Method of gain firing data by calculate the group of differential equation has the advantages of high repeatability and high accuracy But much of the CPU time is occupied by the task of re-iteration in computational processing. Therefore it is not the real time processing. This paper introduces a method to quickly determine angle of firing by iteration method which realizes Runge-Kutta method for the equations of exterior ballistic according to the model of mass center motion of projectile. Moreover it also provides the flow of real-time integral solution and be proved by the simulation of MATLAB. Its accuracy satisfies the requirements. This work can be as reference for the design of opt-electrical fire control system and the demonstration work. 2012 IEEE.

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