2006 Vol. 32, No. 09

Display Method:
Experimental investigation on RCS characteristics of rotating blades
Meng Zhijun, Wu Zhe
2006, 32(09): 1003-1006.
Abstract:
The high frequency backscattering by rotating skew-plated metal blades was investigated experimentally. RCS(radar cross section) was measured in an anechoic chamber. The RCS spectra, relating to Doppler effect, was obtained by FFT(fast Fourier transform) from time-domain signature. The effects on RC...
Entropy generation minimization analysis for aircraft environmental control system optimal design
He Jun, Zhao Jingquan, Yuan Xiugan
2006, 32(09): 1007-1010.
Abstract:
A new method bases on the second law of thermodynamics for entropy generation minimization analysis and thermodynamic optimization in the research and design of aircraft environmental control system (ECS). The chosen example is a military aircraft ECS with an air cycle machine (ACM) and a counter-fl...
Calculation method of critical radar cross section of low pulse repetition frequency PD radar
Ma Dongli, Luo Xun, Pei Xu
2006, 32(09): 1011-1014.
Abstract:
A solution to the problem of calculation on critical radar cross section (RCS) of low pulse repetition frequency (LPRF) PD radar was given. The critical elevation method was adopted to deal with the unknown radar parameters, and combine those parameters into a radar character constant. When the targ...
Time-domain response analysis of a tethered aerostat
Zhang Xiangqiang, Gu Yidong, Jiang Luhua
2006, 32(09): 1015-1018.
Abstract:
To stability analysis of the tethered balloon, a three dimensional nonlinear mathematical model of tethered aerostat was assembled. The tether was modeled using finite difference approximation. The balloon was modeled using rigid-body dynamic model including the static derivative, dynamic derivative...
Aerodynamic-stealth design of conformal fuel tank
Huang Minjie, Huang Jun, Wang Guanlin, Wu Zhe
2006, 32(09): 1019-1022.
Abstract:
Based on the prediction of the influence of aircrafts′ stealth and aerodynamics characteristics by conformal fuel tanks, the method of aerodynamic-stealth design of conformal fuel tanks through a design model was studied, and the effects were compared with the traditional auxiliary tanks. Results sh...
Monte Carlo method for system reliability evaluation using reliability confidence distribution
Zhang Yan, Huang Min, Zhao Yu, Yu Dan
2006, 32(09): 1023-1025.
Abstract:
A Monte Carlo method was presented to ravel out the system reliability estimation problem of large and complex system′s reliability, which is a hot and difficult spot in the reliability engineering field. The reliability samples of system′s units from their reliability confidence distribution and sy...
Engineering system health formulation and health monitoring based on GFRF approach
Gao Zhanbao, Li Xingshan, Liang Xu, Yu Jinsong
2006, 32(09): 1026-1030.
Abstract:
The health management concept was burgeoned as the application of engineering system. Several basic formulation definitions, such as health vector, health index, health function, were presented to mitigate the lack of formal concepts for the system health. Compared with the traditional condition par...
Image quality assessing model by using neural network and support vector machine
Tong Yubing, Zhang Qishan, Chang Qing, Qi Yunping
2006, 32(09): 1031-1034.
Abstract:
Pear signal to noise ratio(PSNR) and structure similarity(SSIM) as two indexes describing image quality were used with neural network(NN) and support vector machine(SVM) to set up new effective image quality assessing model. The definition of isolated points and the prediction of isolated points wer...
Approach of range ambiguity suppression for spaceborne SAR based on LCMV algorithm
Yu Ze, Zhou Yinqing, Chen Jie, Li Chunsheng
2006, 32(09): 1035-1038.
Abstract:
The range ambiguity suppression is a key problem in the design of the spaceborne synthetic aperture radar(SAR) system. Increasing the antenna height can solve this problem. But usually the satellite platform can not load the large antenna, which restricts the size of the antenna. The importance of s...
Design of a high-performance microstepping driver for two-phase stepping motors
Zhang Qinling, Li Yanming, Guo Hong
2006, 32(09): 1039-1042.
Abstract:
Based on mixed-signal ISP flash MCU C8051F005 and full-bridge pulse width modulation(PWM) integrated circuit 3955, a microstepping driver with high performance, simple structure and ultra small size was designed for two-phases hybrid stepping motors. The driver utilized advanced sinusoidal current s...
Slots allocation in CDM GDP
Zhou Qian, Zhang Xuejun, Liu Zhongkan
2006, 32(09): 1043-1045.
Abstract:
When encounters bad weather, airport capacity is far exceeded by the demand and the resulting delays are a financial and psychological burden for airlines and passengers. CDM(collaborative decision making) GDP(ground delay procedure) is the right Air Traffic Flow Management procedure to settle such ...
Design of extended video encoder with pre-processing of interlace signal
Yao Chunlian, Li Wei, Meng Qinglei
2006, 32(09): 1046-1050.
Abstract:
Video coding stands gives out several coding methods for interlace signal. However, many kinds of macroblock division methods for motion estimation, which makes these methods very time-consuming and can′t be used actually. So an extended video encoder was designed, motion-adaptive de-interlacing was...
Numerical reflection analysis of PML absorbing boundary in 3-D GA-A3DI-FDTD method
Zhang Yan, Lü Shanwei
2006, 32(09): 1051-1054.
Abstract:
Attention was focused on a new method to reduce the numerical dispersion of the 3-D ADI-FDTD (three-dimensional alternating-direction implicit finite-difference time-domain) method through artificial anisotropy. First, the numerical formulations of the 3-D ADI-FDTD method were modified. Second, the ...
Digital modeling of double press axial piston pump and its thermal analysis basing on AMEsim
Lu Ning, Fu Yongling, Sun Xinxue
2006, 32(09): 1055-1058.
Abstract:
Hydraulic system simulation model of double press axial piston pump was established in AMESim. Movement function, flux function and swash plate model of axial piston pump were created, and carried on the corresponding simulation computation. Control valve simulation model of double press axial pisto...
Modeling and characteristics analysis of redundant direct drive servo actuating system
Jin Hongtao, Jiao Zongxia, Li Chenggong, Zhou Rusheng
2006, 32(09): 1059-1062.
Abstract:
To improve reliability of the digital direct drive servo actuating system, the system was configured redundantly with the electrical components of three redundancies and the mechanical components of two redundancies. Redundancy configuration and management scheme of the redundant servo actuating sys...
Key techniques of information retrieval from science and technology resources
Zhang Hui, Wu Hui, Liu Rui, Zhou Gang
2006, 32(09): 1063-1066.
Abstract:
In order to search and utilize science and technology resources, which are usually distributed, hybrid, complex and massive, with high efficiency, some measures were provided on how to organize, represent, transmit and access these resources. A three-layer architecture, which consisted of data layer...
Application of wavelet network for induction motor in direct torque control system operating at low speed
Liu Lin, Shen Songhua, Liu Qiang
2006, 32(09): 1067-1071.
Abstract:
To improve the low-speed dynamic performance of induction motor DTC(direct torque control), a novel method of stator resistance identification based on WN(wavelet network) was presented. The inputs of the WN were the current error and the change in the current error and the output of the WN was the ...
Design and analysis of based on PNN and FNN controller
Wang Kai, Wang Zhanlin, Fu Yongling, Qi Xiaoye
2006, 32(09): 1072-1076.
Abstract:
Fuzzy neural net(FNN) and predictive neural net(PNN) are new neural net controllers, two neural net controllers based on practical methods from actual control system and self-study. FNN and PNN controllers avoid many shortcomings of usual artificial neural net. Two neural nets for electronic-hydraul...
Parallel algorithm realization of high range resolution radar based on multi-processor
Fan Xiaobo, Zhang Yongjie, Wang Jun, Li Shaohong
2006, 32(09): 1077-1082.
Abstract:
An advanced real-time pulsed Doppler-pulse compressed radar signal processing system that managed to track targets with high velocity was implemented based on 8 ADSP- TS201 TigerSHARC processors. System structure designing was discussed, including DSP(digital signal processors) topology, communicati...
Forming limits for as-quenched aluminum alloy sheet
Gao Hongzhi, Zhou Xianbin
2006, 32(09): 1083-1086.
Abstract:
FLD(forming limit diagram) was influenced by the material properties as well as forming process, such as strain path and heat-treatment states, etc. Some experimental FLDs were constructed for 2D12 aluminum alloy in the annealed, pre-strained and various aging time conditions after solution heat-tre...
Design of bionic flapping mechanism and its kinematic analysis
Jia Ming, Bi Shusheng, Zong Guanghua, Xu Yicun
2006, 32(09): 1087-1090.
Abstract:
Bionic flapping mechanism aims at realizing flapping motion of insect wings. It has become clear that two-degree-of-freedom flapping motion harmoniously is necessary for insects to produce enough lift. Double four-bar linkage mechanism and differential planetary gear train are two elements of bionic...
Quadratic surface fitting and uncertainty analysis of fitting parameters
Zhang Xi, Hu Chunhua, Chen Wuyi
2006, 32(09): 1091-1095.
Abstract:
The quadric surface fitting through cloud points was described as the constrained nonlinear optimization. The calculation of initial fitting parameters and optimization algorithm were summarized, and then the influence of point coordinate measurement error on fitting parameters and evaluation of sur...
Process examination system of aircraft sheet metal parts based on KBE
Ao Yonggang, Wan Min, Li Xinjun
2006, 32(09): 1096-1099.
Abstract:
Because the sheet formability rests with various factors, the process examination of sheet metal parts is very complicated. The scientificity, rationality, veracity and reliability of process examination are the main factors in the aircraft design and manufacture. The importance of using the knowled...
Experiments on dynamic dehumidification of internally cooling compact solid dehumidifier
Zheng Yi, Yuan Weixing, Wang Hai, Yuan Xiugan
2006, 32(09): 1100-1103.
Abstract:
An internally cooling compact solid dehumidifier was built and studied experimentally. Silica gel as the desiccant was coated to all the surfaces of primary process airflow channels of the dehumidifier. Experiments on performance of the dehumidifier with and without secondary cooling airflow were ca...
New manipulator calibration method based on screw theory and distance error
Tan Yuesheng, Sun Hanxu, Jia Qingxuan, Shao Zhiyu
2006, 32(09): 1104-1108.
Abstract:
Accuracy of a manipulator is determined by its ability to position and orient its end-effector at the desired point in its workspace. It must be calibrated in order to improve its position accuracy. Kinematic model and the disturbance of exterior error are critical to the manipulator calibration. Th...
Thermal analysis for dynamic behavior of microcellular polycarbonate
Lu Zixing, Zhang Hui
2006, 32(09): 1109-1112.
Abstract:
The dynamic behavior of microcellular polycarbonate for different densities at different temperatures and frequencies was investigated by means of dynamic mechanical thermal analysis. The relations of storage modulus and loss factor with temperature, frequency and density were discussed at the same ...
Fast reconstruction method based on C-arm tomosynthesis
Zhang Lijun, Liu Wenyong, Wang Tianmiao, Hu Lei
2006, 32(09): 1113-1116.
Abstract:
As the traditional tomosynthesis is not appropriate for C-arm based slice reconstruction, a modified tomosynthesis method, CTS(C-arm based tomosynthesis), was proposed. CTS method rotates and overlays all the X-ray projections in 3-D space according to the mapping matrices of different angles, which...
Application of maturity in development of aircraft integrated process
Tao Jian, Fan Yuqing
2006, 32(09): 1117-1120.
Abstract:
Improving the level of integration of aircraft design and manufacturing has become a necessary to meet the market requirement of modern aircraft and to avoid the maximum risk of technology and quality. The importance of maturity technology was emphasized and the definition of maturity was confirmed ...
Evaluation on distribution of measured characteristic with asymmetric tolerances
Zhu Wei, Li Yuansheng
2006, 32(09): 1121-1124.
Abstract:
The quality of a process or product was studied based on the center of the specification interval in the conventional SPC but on target value, which led to inadequate measure of the quality under the condition of asymmetrical tolerances. In terms of this problem, the quality of a process or product ...
End-points error controlling method for torus tool position optimization in five-axis NC machining
Jin Man, Zhang Li, Chen Zhitong
2006, 32(09): 1125-1128.
Abstract:
There were two points in the character-curve whose errors were equal to the required tolerance of the contour. And in the cutter surface and the to-be-machined surface, the corresponding points existed. Based on the phenomenon, a novel algorithm was brought forward. It was mainly to optimize the too...