Table of Content

30 November 2011, Volume 32 Issue 11

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Paper

Study on Comparison Analysis of Planar and 3D Numerical Methods During Wedge-caulking Process of One-way Clutch

WEI Wei， LIU Shu-cheng， YAN Qing-dong， DU Da-yong

2011, 32(11):  1305-1309.  doi:10.3969/j.issn.1000-1093.2011.11.001

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For one-way clutch of integrated hydrodynamic torque converter with logarithmic spiral mold surface, the stress distribution of roller, internal and external ring in the transient wedge-caulking process was investigated. Based on explicit dynamics, two-dimension planar strain and three-dimension finite element analyses were carried out, and this transient process was investigated numerically from the viewpoint of two-dimension and three-dimension respectively. Simulation results show that, compared with the planar strain analysis, the three-dimension analysis can provide axial stress distribution of each part, and the simplification from three-dimension to two-dimension analysis is feasible, and the consistency of calculation results derived from two analysis methods provides more reliable theoretical foundation for the design and calculation of one-way clutch.

Numerical and Experimental Study on Gas Intake Process in Diesel with High Pressure Drop

SUN Li-wei，SU Tie-xiong, XU Jun-feng, WANG Qiang, XU Chun-long, YOU Guo-dong

2011, 32(11):  1310-1314.  doi:10.3969/j.issn.1000-1093.2011.11.002

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The study focuses on the flow in the intake port of a high-specific-power diesel with high pressure drop. A numerical model for such intake port was built by AVL BOOST and AVL FIRE. The model consists of a 1D unsteady model and a 3D steady one. 3D steady flow of the gas intake port in the diesel with high pressure drop was analyzed. The intake valve flow coefficient of the 1D unsteady model was modified using the 3D numerical result. Then the intake port of such diesel was improved on the basis of the modified numerical model. It can be known from the high-pressure-drop steady flow test that the improved gas intake port provides a fine gas intake performance.

Experimental Research on Natural Frequency Characteristics of Self-propelled Guns

WANG Bao-yuan, LIU Peng-ke, HENG Gang, SHAO Xiao-jun, YU Hua-sa，WU Hui-min

2011, 32(11):  1315-1319.  doi:10.3969/j.issn.1000-1093.2011.11.003

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To investigate the structural dynamic rules of the self-propelled gun, the modal test experiments were carried out and the natural frequencies and the modes were obtained of the wheeled and tracked self-propelled guns. Analyzed their natural modes, it is concluded that, for both self-propelled guns, the natural modes from low to high frequency are pitch, fluctuation and roll; the natural frequencies in three modes of the tracked self-propelled gun are higher than those of the wheeled self-propelled gun; both operational and traditional modal analysis methods are suitable for the modal test of the wheeled self-propelled gun, and the operational modal analysis method is suitable for the modal test of the tracked self-propelled gun.

Thermal Decomposition Mechanism and Non-isothermal Pyrolysis Kinetic Analysis of BAMO-AMMO Copolymer

SONG Xiu-duo, ZHAO Feng-qi, WANG Jiang-ning, TIAN Jun, ZHANG La-ying, GAN Xiao-xian

2011, 32(11):  1320-1326.  doi:10.3969/j.issn.1000-1093.2011.11.004

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The thermal decomposition process and mechanism of poly (BAMO) (3,3-diazidomethyl oxetane) and poly(AMMO) (3-azidomethyl-3-methyl oxetane) (BAMO-AMMO) copolymer were investigated by means of DSC, TG-DTG, heating in-situ cell/FTIR, and thermolysis/mass spectrograph. The decomposition mechanism of BAMO-AMM

The Influence of Morphology of Al Powder on Combustion Performance of Al/KClO₄ Composition

CUI Qing-zhong， JIAO Qing-jie， PENG Chen-guang

2011, 32(11):  1327-1330.  doi:10.3969/j.issn.1000-1093.2011.11.005

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The morphology of aluminium powder has a great effect on the combustion performance of aluminized compositions. The thermal behavior and burning performance of Al/KClO₄ composition which containes different types of aluminium powder were investigated by a differential scanning calorimeter (DSC), and the thermal decomposition equations of crystal shape conversion, melting, interfacial liquid phase reaction, and gas phase oxidation reaction were concluded. The influence of morphology on combustion performance was studied from the aspect of decomposition temperature, combustion heat and rate, and the thermal decomposition mechanisms of compositions were concluded. The results shows that the dominant reaction of compositions was an interfacial oxidation reaction of atomic Al with molten KClO₄.

Denoising Algorithm for Dynamic Digital X-ray Image Sequences and Its Fast Implementation

YANG Min， MENG Fan-yong， LIANG Li-hong， WEI Dong-bo

2011, 32(11):  1331-1336.  doi:10.3969/j.issn.1000-1093.2011.11.006

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In order to realize the fast noise reduction in the dynamic digital radiography (DR) imaging system, the system’s noise characteristics and the disadvantages of the original NL-means denoising algorithm were studied. An improved NL-means noise reduction algorithm was proposed. Meanwhile, in order to solve its calculation complexity problem, graphic processing unit (GPU) was applied to make use of its high parallel and fast floating-point calculation abilities. In the implementation, the image was mapped to the GPU’s texture and multi-thread parallel calculation was adopted. The experimental results showed that the improved NL-means noise reduction algorithm could effectively restrain the quantum noise and improve the resolution of DR image sequences. In addition, the acceleration with GPU could realize the real-time denoising without the loss of image information.

Cooperative Search and Path Planning of Multi-unmanned Air Vehicles in Uncertain Environment

WU Wen-chao，HUANG Chang-qiang，SONG Lei，TANG Shang-qin，BAI Ren-chao

2011, 32(11):  1337-1342.  doi:10.3969/j.issn.1000-1093.2011.11.007

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In order to resolve the cooperative search problem of multiple unmanned air vehicles (UAV) in a uncertain environment, this paper presents a basic framework for it first, and then gives the search environment and UAV models. Based on them, a cooperative search path decision for UAV to satisfy the maximum turn radius restriction and communication delay is proposed. According to prior knowledge, the environment can be divided as unknown regions, known regions and prohibited areas, and an award function can be designed for a team of UAVs to search the unknown regions and avoid the known regions. By using an avoidance decision, UAV can get rid of the prohibited area ultimately. Finally, these ideas are simulated and compared with the uncooperative search patterns. The simulation results demonstrate the efficiency of the proposed cooperative approach.

Application of Super-resolution Spectral Estimation in Velocity-measurement Radar

TAN Yuan, YANG Yong, YUAN Nai-chang

2011, 32(11):  1343-1347.  doi:10.3969/j.issn.1000-1093.2011.11.008

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To measure the rotating velocity of the flying bullet, this paper analyzes the RCS of the bullet with slot first, and adopts the modern spectral estimation of the ‘effect of spatial smoothing on state space methods’ (ESPRIT) to replace the general FFT. Simulations and tests under different SNRs evaluate the spectral estimation performance of this new method proposed in this paper, and the relations between measurement error and SNR are obtained. The results show that the method improves the precision of velocity-measurement greatly.

An Image Fusion Algorithm with Entropy Measure Based on Non-subsampled Contourlet

LI Ao, LI Yi-bing, LIU Dan-dan

2011, 32(11):  1348-1352.  doi:10.3969/j.issn.1000-1093.2011.11.009

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The feature information extracted by using activity measure, a very important measure in the process of image fusion, determine a certain input image with more obvious characteristics. In wavelet-based fusion algorithm, the common activity measures consider the coefficients of all high-frequency sub-bands themselves only, and ignore the information provided by low-frequency coefficients. An algorithm based on the general method and added the entropy-masking obtained from the low-frequency coefficients as an active measure is proposed in this paper to comprehensively consider the impact of the high and low frequency coefficients on the activity measures. And, the fused image with different activity measures and objective performance evaluation index are provided also. The results show that the entropy-masking measure is better than several other traditional measures for image fusion.

A Feature Matching Algorithm Based on Template Partition Weighted Hausdorff Distance Matrix

XU Yi-ming， LIU Xiao-li， LIU Yi-xin

2011, 32(11):  1353-1358.  doi:10.3969/j.issn.1000-1093.2011.11.010

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A feature matching algorithm based on template partition Hausdorff distance matrix was proposed to resolve the problems of large scale target occlusion and serious noises in TV guidance process. The template image could be divided into several sub-templates and the corners were detected by using SUSAN operator. Hausdorff distance matrixes between sub-templates and searching image were constructed by calculating weighted Hausdorff distance based on the corner response function. Corrected by corner density matrix, a similarity measure was obtained, and the matrix with a minimal Frobenius norm was corresponding to the best matching position. A target tracking experiment with partial target occlusion and serious spot noise (n=10) was carried out, and the target could be tracked accurately when the difference of feature points in template and correlation area ranged from －43.75% to 56.25%.

Research on Target Feature Extraction Algorithm Based on Statistical Centerline

YU Xiao-liang， MA Hui-min， ZANG He-fa

2011, 32(11):  1359-1364.  doi:10.3969/j.issn.1000-1093.2011.11.011

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In order to recognize the target and cloud effectively in laser near-field detection, a new target feature extraction algorithm suitable for FPGA implementation was presented. It can extract four target image features, such as abrupt change, multi-branch, large-angle, and width variation. The experiment results show that the algorithm can recognize the target accurately.

Research on Schedule Technique for Area-detecting Electronic Reconnaissance Satellite

WANG Hui-lin, QIU Di-shan, HUANG Xiao-jun, MA Man-hao, ZHU Jiang-han

2011, 32(11):  1365-1372.  doi:10.3969/j.issn.1000-1093.2011.11.012

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Because of significantly important role that the electronic reconnaissance satellite (ERS) plays in the fields of antiterrorism and salvage, the problem of area covering-oriented electronic reconnaissance satellite scheduling (ACOERSS) becomes a key problem in ERS scheduling domain. Considered the specific constraints of ACOERSS, the grid space of the area target was established, and a candidate reconnaissance activity constructing method based on the partitions in space domain and frequency domain was proposed. Then, a multi-objective model for ACOERSS was brought forward. Based on the model, an ACOERSS multi-objective evolution algorithm (ACOERSS-MOEA) was put forward to obtain the optimal solutions. Meanwhile, an initial feasible solution construct algorithm based on the determining of time feasibility was designed to produce high quality initial solutions to prevent the algorithm from slow converging. The comparative experiments show that the proposed model and algorithm can effectively deal with the ACOERSS problem better.

Study on Wear Particle Morphology Detection Based on Digital In-line Holography

WANG Yu-rong, XU Yuan-qiang, JIA Xue-dong, LIN Guan-hai, LIU Tao,

2011, 32(11):  1373-1377.  doi:10.3969/j.issn.1000-1093.2011.11.013

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A new technique for oil wear particle monitoring using digital in-line holographic 3D imaging was proposed. As an advanced way for oil monitoring and failure diagnosis of equipments, the developed system can count, imaging, indentify and classify the particles. Its principle, characters, hardware and software were presented. The experiment results show its feasibility.

Research on Available Probability for Satellite-to-ground Laser Communication in Slant Path Atmospheric Turbulence

LOU Yan, CHEN Chun-yi, JIANG Hui-lin, ZHAO Yi-wu,

2011, 32(11):  1378-1383.  doi:10.3969/j.issn.1000-1093.2011.11.014

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The Accessible time and elevation angle of satellite-to-ground link were simulated by using STK program. The effects of atmospheric transmittance, cirrocumulus, intensity scintillation and angle-of-arrival fluctuation were analyzed for different paths from two GEO satellites to three ground stations. Under the visibility of 5 km in city aerosol, weak turbulence and clouds, an adaptive optimal threshold method was proposed to establish the model of communicable probability of the link. The simulation results show that the average available probability of GEO in longitude 75° to Hainan ground station is best, the communicable probability attained near 93% in clear day and 66.7% in cirrocumulus cover day. The analysis on this paper will be helpful for experiments of satellite-to-ground laser communication.

A New Method for Calibration of Rudder Angular Displacement Sensor Based on Monocular Vision

HE Sen, WANG Zhi-bin

2011, 32(11):  1384-1388.  doi:10.3969/j.issn.1000-1093.2011.11.015

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Before flight test, the airplane’s rudder angular displacement sensor needs to be calibrated. The calibration can be based on monocular vision. The test target’s mark is a circle with a centre indicated by the intersection of two lines. The target is fixed on the rudder face, parallel to the rudder axis, and its pictures are taken with a fixed digital-camera. The pictures can be processed by using sub-pixel processing method proposed in this paper. The image point of circle centre, the elliptic equation and its minor axis’s endpoints can be found out. Thus, the target’s plane equation can be obtained also. Then, the rudder angular displacement can be expressed by that of the target. When elliptic was added Gaussian noise with μ=0 and σ=2pixel, simulation results show that the angular displacement errors are within 0.06°. The angular displacement errors caused by the target deviation from the rudder axis can be corrected.

Simulation and Experiment for Linear Induction Coil Propeller

LI Xian, WANG Qiu-liang, WANG Hou-sheng, LIU Jian-hua，CHEN Shun-zhong

2011, 32(11):  1389-1394.  doi:10.3969/j.issn.1000-1093.2011.11.016

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To study the transient process of multi-section linear induction propeller, a two-sections propeller was simulated and analyzed numerically. Also, its was tested to verify the simulation results. Based on the lumped parameter circuit method, a simulation model of the capacitor driven linear induction propeller was built. Then, the simulation code for the dynamic process in the system was programmed in MATLAB. The projectile velocity and force were predicted by using simulation, and the distribution of average temperature rise in the sleeve was described. Finally, the test bench of the propeller was described. Experimental results coincide with theoretical prediction better. It can accelerate a projectile of 300 g in weight to a muzzle velocity of 204 m/s, if the voltage and capacitance on the capacitors of the propeller are 3 kV, 1 500 μF in the first section, and 5 kV, 720 μF in the second section, respectively.

A Calculation Method of Magnetic Leakage Field Based on Finite Element Neural Network

YUAN Xi-chao，WANG Chang-long，JI Feng-zhu，ZUO Xian-zhan

2011, 32(11):  1395-1398.  doi:10.3969/j.issn.1000-1093.2011.11.017

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To reduce computational cost of FEM, a neural network was adopted to simulate the process of finite element analysis, a finite element neural network (FENN) model to calculate the leakage field was established, and a conjugate gradient (CG) method was introduced as a learning algorithm. The magnetic leakage field of a rectangle defect was calculated by using FENN. The magnetic field intensity, magnetic flux density and the x and y components of leakage magnetic flux were obtained. The results indicate that the method has the advantages of rapidness and stability and can be applied to leakage field’s parallel resolving.

Naval Gun Automation Magazine Scheme Decision Based on Support Vector Machine

HU Sheng-hai， XU Peng， HE Lei， YANG Qi， FU Wei

2011, 32(11):  1399-1404.  doi:10.3969/j.issn.1000-1093.2011.11.018

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Aimed at the decision problem of many schemes on a certain large caliber naval gun automatic magazine, a decision model based on samples feature weighted support vector regression was proposed. The demands and principia for scheme selection were analyzed. In addition, the system decision factor sets were fuzzily quantized, and the input samples of the decision model were structured. Some domain experts’ knowledge structure information was used to build the weight vector of decision factor. By means of nonlinear relationship identification for the system decision factor sets and schemes, the decision model founded on the feature weighted kernel function support vector regression was built. The simulation and experiment results show that the decision model based on the support vector regression is effective and practicable.

A New Method for Calculating Plastic Radius of Swage Autofrettage Thick-walled Cylinder

CHANG Lie-zhen， PAN Yu-tian， MA Xin-mou

2011, 32(11):  1405-1410.  doi:10.3969/j.issn.1000-1093.2011.11.019

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To derive a new formula to calculate the plastic radius of autofrettaged thick-walled cylinder, some simulations were run for different friction coefficients. It was found that the friction coefficient did not influence the residual stress and plastic radius. Thus, it is unnecessary to consider the effect of the friction coefficient in deriving the new formula of plastic radius. Also, considered that the radial stress in contact section of swage and thick-walled cylinder are equal during the swage procedure, the formula of plastic radius was derived. By using the formula, the plastic radius of nine different tubes were calculated. It is shown that the theoretical values of plastic radius coincide with the experiment results better. This formula can be used to calculate the plastic radius and over strain according to the excess, or determine the excess according to the overstrain.

Research Notes

A Quad-tree Dynamic Terrain Levels Algorithm

ZHANG Yu-nan, WANG Dong, XIA Yi, LI Han-fei

2011, 32(11):  1411-1415.  doi:10.3969/j.issn.1000-1093.2011.11.020

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To meet the special requirements for the rut visualization in dynamic terrain simulation, a dynamic terrain level of detail (LOD) algorithm based on graphic processing unit (GPU) was proposed. It was used as the terrain deformation algorithm, meanwhile, the tiled block quad-tree algorithm was used to render the deformed terrain. By repeat using a small vertex buffer and index buffer, combined different scales and bias factors, each block was rendered with different levels of detail. To correct the potential cracks between neighboring blocks with different levels, the skirt was added to each block’s border. The skirt was incorporated with the block render method seamlessly. The query for the elevation was fulfilled in the collision detection. Finally, the experiment results show that the method is feasible and valid.

Structural Parameter Optimization of Synchronous Induction Coil Gun Based on Ant Colony Algorithm

LIU Wen-biao，CAO Yan-jie，ZHANG Yuan，ZOU Ben-gui

2011, 32(11):  1416-1422.  doi:10.3969/j.issn.1000-1093.2011.11.021

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Energy conversion efficiency of synchronous induction coil gun is an important limiting factor for its development. Its any electromagnetic parameter change can directly or indirectly affect the electrical-to-kinetic energy conversion efficiency. In order to improve the energy conversion efficiency,an electromechanical model was built first. Then, as an example, an induction coil gun with caliber of 60 mm was optimized by using ant colony optimization algorithm. The electrical-to-kinetic energy conversion efficiency was increased from 5.32% to 15.2%. In order to validate the optimization results, an experiment was carried out in a single stage synchronous induction coil gun, and the results show that the optimization is effectively.

Research on Modeling of Stabilized Aim Control System Based on dSPACE

XU Qing-qing, WU Yu-jing, ZHANG Jing-yue, JIANG Shi-zhou

2011, 32(11):  1423-1427.  doi:10.3969/j.issn.1000-1093.2011.11.022

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In order to improve the analysis and design capability for airborne stabilized aim servo control system, a modeling method based on dSPACE was introduced. The active signal was sent to the object system and the response signal was acquired by using dSPACE. The system’s frequency characteristic was obtained by least square methods and the transfer function was fit by using Ident toolbox in MATLAB. This method was used in the controller design for an airborne stabilized aim servo system, and the validity and practicability were proved by the experiment results.

Design and Experiments for Magnetic Fluid Seal of Tank Panoramic Mirror

CHEN Yan， LI De-cai

2011, 32(11):  1428-1432.  doi:10.3969/j.issn.1000-1093.2011.11.023

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The seal of tank panoramic mirror is always difficult. In order to solve this problem, a magnetic fluid seal method is used in this paper and the tank panoramic mirror seal structure is designed also. The magnetic filed distribution and the resistance to pressure are analyzed theoretically. The experiment results indicate that the designed structure is correct and the seal performances are better in pressure, temperature, wet-hot and salt-fog tests.