Table of Content

30 July 2011, Volume 32 Issue 7

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Paper

Research on Hull Attitude Adjustment Method in Variant Design of Tracked Vehicles

SHANG Qi-gang， WANG Hong-yan， MA Wei-biao， WANG Liang-xi

2011, 32(7):  785-789.  doi:10.3969/j.issn.1000-1093.2011.07.001

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A novel method based on virtual prototype and parametric optimum techniques is proposed to solve the problem of hull attitude adjustment in variant design of tracked vehicles. Firstly, a multi-body dynamic model of the variant vehicle is established and validated experimentally. Then, the initiative mounting angles of road arms can be chosen as design variables, the distance between the ground and the bottom of hull can be defined as a restricted condition, and the hull attitude can be taken as the object function of parametric optimization. Finally, the hull attitude of the optimized vehicle and the maximum shearing strength of torsion bar spring are checked, the feasibility of adjusting attitude method proposed in this paper is verified.

Study on Diesel Engine Anomaly Detection Based on Hyper-sphere Classification with Maximal Distance

WU Ding-hai, ZHANG Pei-lin, REN Guo-quan, FU Jian-ping

2011, 32(7):  790-794.  doi:10.3969/j.issn.1000-1093.2011.07.002

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Aimed at insufficiency and imbalance data distribution in diesel engine fault detection, an abnormal detection method based on hyper-sphere classification with maximum distance was proposed. Analyzed the poor generalization capability of support vector data description model and the merits of the optimal separation hyper-plane of support vector machine, the ratio of the radius to the separation margin and the abnormal samples information were introduced to balance the description accuracy and generalization ability of the hyper-sphere. Then, an optimal selection method for the model parameters was presented with the valuation index of the number of support vectors and area under curve of receiver operating characteristics. The diesel engine anomaly detection results show that the proposed method is more effective than SVDD.

Implementation of Three Shooting Modes for Distributed Fire Control System of Antiaircraft Gun

WANG Zhong-xu, CHEN Li

2011, 32(7):  795-800.  doi:10.3969/j.issn.1000-1093.2011.07.003

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In the distributed fire control system, a traditional shooting mode is to shoot at the same time. When the interval between fire units becomes larger, it can not work well under the limit of space baseline, effective shooting height and distance of the fire units. Keeping this mode, two novel shooting modes, i.e. shooting on the same range and shooting the same coming point, are designed. The former can insure that the fire units shoot on their best distances, and the later can insure that the fire units hit the same point. Considering practical applications, the implementations of these shooting modes are presented, and their rationality and feasibility are illustrated by using numerical simulation and range test of a certain type of distributed fire control system.

Simulation Research on Motion Reliability of High-speed Feed Mechanism

CHENG Gang， ZHANG Xiang-yan， DONG Zhi-qiang， DONG Jing-fang

2011, 32(7):  801-804.  doi:10.3969/j.issn.1000-1093.2011.07.004

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In order to improve the motion reliability of high speed feed mechanism in high firing-rate whirling auto gun, the motion reliability simulation methods was studied, and a dynamic simulation model was established. The parametric driving simulation could be carried out by using random sampling to simulate the initial setting angle error of the transmission gear in the feed mechanism. Based on stress-strength interference model, the motion reliability of feed mechanism was calculated. Compared the calculation results, the design parameters were optimazed. The experiments show that the optimal feed mechanism can feed projectiles more reliably and the motion reliability simulation method is an effective method for the high speed feed mechanism.

Design Optimization and Performance Analysis of Loading Mechanism of Impact Fatigue Test Machinefor Firearm Automaton

HE Ling， XU Cheng

2011, 32(7):  805-811.  doi:10.3969/j.issn.1000-1093.2011.07.005

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An impact fatigue test machine was designed in order to test the life of critical components in firearm automaton under repetitive impact load. The structure of loading mechanism was developed for the special requirements of impact fatigue test of automaton. The parameters of the cam in the loading mechanism were optimized by using a genetic algorithm. The optimized loading mechanism was decreased in volume by 28%. The impact pulse was characterized by width, peak value and impulse of impact pulse, and four variables, i.e. impact mass, velocity, contact stiffness k_c and stiffness k_e could be taken as the adjustment parameters. The adjustment method and performance parameters of impact pulse were obtained by calculating the relation between variables and impact pulse. The results are important for the design of impact fatigue test machine.

Research on Consistency Maintenance and Mapping Mechanism of Model Structure in CollaborativeDesign of Automatic Weapon

LOU Li， XU Cheng ， ZHANG Fei-meng

2011, 32(7):  812-818.  doi:10.3969/j.issn.1000-1093.2011.07.006

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The cooperative function of current CAD software is limited, and its assigned model has oversize data, so it is unable to response the design activities efficiently. A method of model consistency maintenance and mapping mechanism based on parameterized modules which can be configured and reused with a view to rapid collaborative design was studied and designed. Utilized the structured description language to depict model properties, modeling data and correlative operation information, a synchronized modeling method based on the replication mechanism of local variable parameters was proposed. It is useful to exchange the local variable data and object functions with light load, which can satisfy the requirements of rapid collaborative design and practical engineering applications.

Research on Data Mining of Redundant Angle Information in Optic-electric Tracking System withIntermittent Observations

CHEN Li, WANG Zhong-xu

2011, 32(7):  819-826.  doi:10.3969/j.issn.1000-1093.2011.07.007

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For mining the redundant angle information in optic-electric tracking systems composed of laser range finder and precision angle measurement device under intermittent observations, a federal filter was designed on the basis of the posterior confidence residual test algorithm. Firstly, the position detection channel in traditional optic-electric tracking system was decomposed into two independent detection channels according to physical structure. Then, the target motion states were estimated by use of the detection data of two channels respectively, and a global state estimate was obtained by fusing these two state estimates. Finally, the information sharing of the federal filter was done according to the global state estimate and the posterior confidence of detection channels. Monte Carlo simulation and measurement data show that the proposed filter can obviously improve the estimation performance of optic-electric tracking systems by mining redundant angle information without increasing any hardware cost, and its root mean square of estimate error (RMSE) is close to the average Cramer Rao low bound (CRLB) of tracking systems.

Hybrid Imaging of Optical Aberration Imagery with Random Wave-front Coding

LUO Lin, GAO Xiao-rong, WANG Ze-yong, WANG Li

2011, 32(7):  827-831.  doi:10.3969/j.issn.1000-1093.2011.07.008

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A hybrid imaging was investigated to remove the optical aberrations by random wave front coding and digital image processing. The random phase mask made of laser speckle interference was placed in light path before the optical system image detector to change aberration image into random encoding intermediate image, and the optical deterministic aberrations was submerged in random encoding, so weakened. The blind deconvolution decoding algorithm based on frequency-domain conjugate gradient optimization was established for decoding intermediate image into no aberrations image. Due to using the frequency domain gradient optimization, the decoded image speed is improved. The influence of symmetrical, asymmetric and mixed aberrations, etc on encoding imaging was analyzed. Also the ability of noise inhibiting of encoding imaging is shown. The computer simulation and laboratory experiment were done, the results show that the proposed method can effectively eliminate optical system aberrations, reduce the noise, improve the imaging quality, and have resolution of optical system reach the diffraction limited level.

Estimation on Laser Echo Rate of Opto-electric Tracking Systems

SUO Xiao-feng， CHU Tian-peng， SHENG An-dong, QI Guo-qing

2011, 32(7):  832-837.  doi:10.3969/j.issn.1000-1093.2011.07.009

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For the optimization of the laser echo rate in the target measurement system, the laser echo is considered as a sequence with intermittent observation in this paper. Its lower bound is described as an optimal solution of the nonlinear matrix inequality (NMI) which is solved by using a perturbation linearization method. The laser echo rates in uniform linear, circular and pitchdown airways are simulated. The simulation results show that the statistical evaluated error covariance all converge for any initial value, when the laser echo rate is greater than the lower bound. This algorithm avoids the shortage of traditional method depended on the experience to determine the laser echo rate. Therefore, it can be used in the optimal design of the laser echo rate in the target measurement system.

A Missile-borne SAR Autofocus Method Based on Quantum Particle Swarm Optimization Algorithm

TAN Qin-yan， SONG Yao-liang

2011, 32(7):  838-846.  doi:10.3969/j.issn.1000-1093.2011.07.010

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A new autofocus method is presented to compensate the phase error in missile-borne SAR echo. This method utilizes the quantum particle swarm optimization (QPSO) algorithm and takes image entropy (IE) as the criterion to search for the optimum solution. It greatly improves the focusing quality of missile-borne SAR to increase the missile’s attack precision. It has better robustness and more rapid convergence compared with the traditional phase gradient autofocus algorithm (PGA). It can compensate the low-frequency high order phase error. Furthermore, this method can be used in many situations, especially for the images without any significant features. The simulation results show the validity of the proposed method.

Joint Estimation for Time Offset and Radar System Error

WU Ze-min, REN Shu-jie

2011, 32(7):  847-852.  doi:10.3969/j.issn.1000-1093.2011.07.011

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A joint estimation algorithm for time offset and radar system detection errors is proposed in this paper. Assuming that the target moves in uniform linear motion, the relationship among detected target position differences, time offset and radar system error is established, and a linear least square estimation algorithm is presented. For multi-radar application situation, a variance-based weighted fusing algorithm is especially designed, and it can promote the joint estimation performance with fewer common targets. The simulation results show that the precision of estimated time offset is guaranteed once it’s under tolerance of track correlation algorithm.

Research on the Strong Magnetic Field for Pulse MHD Generator

XIE Zhong-yuan, ZHOU Lin

2011, 32(7):  853-859.  doi:10.3969/j.issn.1000-1093.2011.07.012

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Aimed at the especial requirements for strong magnetic field in pulse MHD genera

Optical Non-contact Composite Measurement of Surface Defects of Hemispherical Shell

FANG Hai-yan , LIU Xiao-yong, LE Jing, GUO Jun-jie

2011, 32(7):  860-865.  doi:10.3969/j.issn.1000-1093.2011.07.013

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To achieve high-precision and non-contact measurement of outer and inner surface defects on hemispherical shell, a optical composite measurement method was proposed on the basis of a new type of non-orthogonal coordinate measuring machine. It combined the laser probe’s point-scanning with the vision probe’s surface-scanning, and could measure not only the coverage and distribution of the surface defects, but also their depth/height. Actual measurement results show that the method is feasible, precise and efficient.

Analysis on Effect of Combustor Structure on Energy Transition in Micro-thermophotovoltaic System

TANG Ai-kun , PAN Jian-feng , XUE Hong , LI Xiao-chun , SHAO Xia , LI De-tao

2011, 32(7):  866-871.  doi:10.3969/j.issn.1000-1093.2011.07.014

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Four different plane cell combustors were designed for the micro-thermophotovoltaic system, corresponding energy transition models were constructed and the calculation program was developed, considered the non-uniformity of wall temperature distribution and the radiation view factors. The effects of combustor structures on the energy transition were calculated and the wall temperature distribution, spectrum distribution of radiation energy, efficiency of each part and the electric power output were analyzed when the nozzle shape, porous media and catalyst surface were changed. The results show that the filling of porous media, using of expanding nozzle and catalyst surface can all increase the average wall temperature, change the temperature distribution especially the high temperature area position, thus, the spectrum radiation force and effective radiation energy are improved also. All energy transition aspects of the three systems using the improved combustor structures are better than the round nozzle one, and the system that uses the expanding nozzle and catalyst surface can increase the total efficiency by 56.6% for the same fuel, and its power density can reach to 0.87 W/cm³.

Optical Inspection Method for Surface Defects of Micro-components

LI Xiao-zhou， YU Hua-dong， YU Zhang-jiang， LIU Yan， XU Jin-kai

2011, 32(7):  872-877.  doi:10.3969/j.issn.1000-1093.2011.07.015

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In order to realize the rapid precise detection for surface defects of micro-components, the optical detection technology was studied. Taking a typical micro ring component as object and considering its surface features and defect characteristics, an optical detection system was established on the basis of machine vision and pattern recognition. Through studies of the surface flaw texture in the component, an algorithm using weighted information entropy of image gradient variance was proposed to suppress the random surface texture, extract the flaws and detect the flaws in the micro-component. Experiment results show that the algorithm can effectively detect the flaws, and the recognition rate of the defect is about 96.5%. Also, the experiments verify its correctness, rapidity and preciseness.

Attenuation of 0.532μm Laser Beam Through Raindrops

GUO Jing, ZHANG He, WANG Xiao-feng

2011, 32(7):  878-883.  doi:10.3969/j.issn.1000-1093.2011.07.016

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Rainfall can bring serious attenuation to the laser signals, so it has some influence on the laser proximity fuze applied in the rain. The attenuation of laser beam propagating in the rain has been researched in the infrared range, but the attenuation of visible light laser in the rain has not been reported. Therefore, based on the Fraunhofer diffraction and geometric optics theory, an attenuation model for 0.532 μm laser beam propagating through the raindrops was established. Then the transmittance of several raindrops was theoretically calculated and validated by experiments, and the error was less than 2%. The investigations indicate that absorptivity of the raindrop for 0.532 μm laser beam is 1.32×10^－9 and can be ignored, so only the raindrop scattering is considered in the laser transmission and influenced by the diffraction and geometric scattering synchronously. The transmittance of near infrared laser is lower than that of 0.532 μm laser due to the raindrop absorption. The attenuation model of 0.532 μm laser provides a theoretical basis for the green laser applied in the proximity fuze operating in the rain.

Calculation of Bending Stress of the Asymmetric Gear Tooth Root Based on Friction Between Teeth

LI Xiu-lian， WANG Gui-cheng， ZHU Fu-xian， ZHOU Jin-yu， HE Qing

2011, 32(7):  884-889.  doi:10.3969/j.issn.1000-1093.2011.07.017

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The effect of the sliding friction can not be neglected in the tooth root bending stress calculation. Taking an asymmetric driving gear as a research object, this paper deduces the calculation equations of the driving gear tooth root bending stress, which consider the sliding friction between teeth, and offers the computation flowchart, for the meshing point characteristic both in single tooth and double teeth mesh, respectively. And the factors which influence the tooth root bending stress are analyzed. The simulation results show that the friction has great effect on the tooth strength.

Research Notes

Research on Laser Beam Divergence Angle Measurement Method Based on Spot Image

SHEN Lin, YANG Jin-hua, HAN Fu-li, JIANG Hui-lin, WANG Chun-yan, XIE Dian-guang

2011, 32(7):  890-895.  doi:10.3969/j.issn.1000-1093.2011.07.018

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Laser beam divergence angle measurement by spot image is often restricted by the camera dynamic range. Adding attenuators will affect the distributed characteristics of the spot, thus influence the measurement accuracy. Making use of the camera linear dynamic range, a practicable image measurement method for the divergence angle is presented in this paper. After using the mean filter on the critical saturated spot images, the divergence angle measurement uncertainty can be increased to 0.02 mrad. Simultaneously, a method for image fusing is proposed, which fuses the under-exposure and over-exposure spot images, to expand the camera dynamic range, then, the overall distribution characteristics of laser spot can be obtained. The experiment results verify the efficiency and divergence angle measurement accuracy of the proposed method.

Self-adaptive Wavelet Threshold De-noising Method and Its Application in Image Processing

LIN Jie， FU Meng-yin, LI Dao-ping

2011, 32(7):  896-900.  doi:10.3969/j.issn.1000-1093.2011.07.019

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For the problem image de-noising, a new method based on self-adaptive wavelet threshold algorithm was proposed. It can decide the threshold of wavelet analysis automatically according to the noise characteristics in wavelet transform, then takes PSNR as a function of filter parameter and acquires the optimal threshold parameter by using midpoint method. It has the strong self-adaptation, simple calculation，good de-noising result and so on. Experiment results show that this new method is much better than original threshold de-noising algorithms and achieves better visual effect.

The Study of Requirement Forecasting and Decision-making Methodology of Equipment’s MaintenanceSpares-parts

LI Shu-guang， ZHAO Yan-Jun ， XU Cheng

2011, 32(7):  901-905.  doi:10.3969/j.issn.1000-1093.2011.07.020

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In allusion to the problem of requirement forecasting and decision-making methodology of equipment maintenance spares-parts, and based on the statistical data about requirement of maintenance spare-parts of a certain specific equipment, a knowledge-representation system on the requirement of equipment maintenance spares-parts of this battle unit was built up with the method of rough set consistent-appreciative denoted space model. Then the method was employed to make attribute reduction and rule amalgamation of the information system for decision-making, and a better rule for forecasting and decision-making was achieved. This study provides an important technical support to get quick and precise forecasting on requirements of equipment spare-parts and achieve the precision of equipment security.

Weapon-target Assignment in Multi-launcher System Based on Improved Integer Field Particle SwarmOptimization Algorithm

YANG Fei， WANG Qing， HOU Yan-ze

2011, 32(7):  906-912.  doi:10.3969/j.issn.1000-1093.2011.07.021

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Weapon-target assignment (WTA) is a classic hard NP problem in military operation research， as its nonlinear integer programming model includes a variety of constraints, and its solution is complex and time-consuming. An improved particle swarm optimization algorithm was used to solve WTA problem. First, a particle decoding scheme and a sufficiency function were proposed for WTA optimization assignment model to solve the problem of integer field initialization. Then, a particle similarity function was used to redefine the velocity and distance concepts in the algorithm. A particle velocity update method and a particle optimization adjust operation plan were proposed to improve the iterative efficiency and optimization ability. Simulation results show that the algorithm is quick and effective, especially for solving real-time WTA problem with large particle group.