Table of Content

31 December 2011, Volume 32 Issue 12

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Paper

Skid-steering Resistance Characteristics of Wheeled Vehicle

LI Xue-yuan， ZHANG Yu， HU Ji-bin， YUAN Shi-hua

2011, 32(12):  1433-1438.  doi:10.3969/j.issn.1000-1093.2011.12.001

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The steering resistance characteristic of wheeled skid-steering vehicle is studied, and the interaction of tire-ground is analyzed by using the discrete element method (DEM). A micromechanical model for lateral interaction of tire and ground is established by using PFC2D software, and the relationship of resistance-relative slip velocity and resistance-sag depth is simulated. The fitting formula of skid-steering resistance coefficient is given. The result shows that the bulldozing resistance between tire and ground is much higher than friction force.

Image Processing Technology of Semiconductor Laser Night-vision

XIN De-sheng， ZHANG Jian-jia， WANG Shao-jun， WANG Zhao-xin, WANG Hong-zhe

2011, 32(12):  1439-1442.  doi:10.3969/j.issn.1000-1093.2011.12.002

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Semiconductor laser night-vision system using laser as light source, can get the night scene in total darkness conditions at night and low cost.So this system has been widely used in the field of public security, counter-terrorism and transportation. Due to the laser energy is relatively concentrated , the part of license plate is strong light reflection will cause saturation phenomenon,if reduce the illumination energy,also cause the part of the car body too dim to identification, all these will cause difficulties for the type of travel and license plate information extraction.The image processing techniques of semiconductor laser night-vision aim at this problem, night-vision scene in the imaging process, the reasons that lead to deterioration of the image analysis, on this basis, the use of the image gray level transformation, edge detection, feature selection, pattern matching and image frame image processing technology to dispose of the night scene, and availably improve of laser night-vision image quality. Realize the type of travel and number plate recognition,the technology can also be used for military and other civilian areas.

Improved High Dynamic GPS Tracking Algorithm for Precise Attack Weapons

PAN Xi， NIE Yu-ping

2011, 32(12):  1443-1447.  doi:10.3969/j.issn.1000-1093.2011.12.003

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Aimed at the high dynamic problem of GPS receivers in precise attack weapons, a GPS receiver with high order phase-lock loop is studied. The high dynamic tracking performance of a third-order loop is analyzed and the problem in tracking high dynamic GPS signals is investigated. Then, some methods are put forward to solve this problem, such as the bandwidth and the loop gain changed continuously. Simulation results show that these methods are effective.

Linear Quadratic Differential Game Guidance Law with Terminal Constraints

HUA Wen-hua₁， LIU Yang₂， CHEN Xing-lin₂， SONG Shen-min₂

2011, 32(12):  1448-1455.  doi:10.3969/j.issn.1000-1093.2011.12.004

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The linear quadratic differential game guidance problem with terminal constraints is studied. Firstly, zero-effort miss distance and zero-effort impact angle are defined as new state variables to reduce the order of the system by use of terminal projection method. Then, based on the zero-sum differential game theory, a guidance law is derived. The navigation gains, the existence regions of saddle-point solution and the performance of perfect interception are analyzed. Finally, the simulations are carried out for the constant maneuvering target and the square wave maneuvering target interception, respectively. The results show that this guidance law can satisfy the requirements of small miss distance and impact angle error to improve the warhead lethality when the missile has enough maneuvering capability.

Filtering Algorithm for Micro-electro-mechanical Gyroscope of Rocket with Lateral Thrust Control

LU Xiao-dong， ZHOU Jun， HE Yuan-jun， ZHAO Bin

2011, 32(12):  1456-1461.  doi:10.3969/j.issn.1000-1093.2011.12.005

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The attitude of rocket oscillates in high frequency when it is controlled by lateral thrust, and its micro-electro-mechanical systems（MEMS）gyroscope will be affected. Most of current filtering algorithms assume that the roket attitude changes slowly in a short interval, and it will generate unacceptable modeling error. With aerodynamic analysis, it can be seen that the attitude oscillation is a natural frequency damping oscillation and the natural frequency and damp ratio can be estimated in advance. Thus, a novel filtering algorithm is proposed, which applies the interacting multiple models (IMM) with swing Markov model to describe the uncertain roket attitude motions. Furthermore, the dynamic adjustment mechanism of state transferring probability matrix with the lateral thrust control command can be introduced. Finally, the numerical simulation indicates that IMM filtering algorithm with swing Markov model can accurately trace the attitude vibration.

Research on Vertical Impact Terminal Guidance Law Based on Sliding Mode Disturbance Observer

ZHU Kai， QI Nai-ming

2011, 32(12):  1462-1467.  doi:10.3969/j.issn.1000-1093.2011.12.006

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The problem of terminal precision guidance for missiles with vertical attack angle constraint is considered. A sliding mode disturbance observer and enhanced adaptive proportional guidance law are applied to improve the robustness. Considering the constraints of target location and attack angle, the guidance parameters selections in longitudinal and lateral planes are analyzed. The uncertainties of the dynamics are estimated by using a second-order sliding mode disturbance observer, and then compensated to ensure high accuracy in the realization of guidance commands. Simulation results demonstrate the robustness and accuracy of the proposed approach. Compared with the conventional adaptive proportional guidance approach, the guidance precision of proposed approach is obviously improved in the present of aerodynamic dispersions.

Fast Self-alignment Method for Inertial Platform Through Continuous Rotation

CAO Yuan， ZHANG Shi-feng， YANG Hua-bo， CAI Hong

2011, 32(12):  1468-1473.  doi:10.3969/j.issn.1000-1093.2011.12.007

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Aims at the accuracy and speed of initial alignment of inertial platform restricted by the test conditions, a fast self-alignment method based on continuous rotation is proposed. Firstly, the error model for platform rotation is established. Then, the theory about system’s output sensitivity for parameters is introduced to analyze the observability of the error model. Finally, the rotation scheme is designed and validated in simulations. The results show that the method proposed can overcome the disadvantage on observability for traditional alignment ways and quickly estimate the misalignment angles with high accuracy.

Research on Launch Acceptable Region for Guided Bombs in Air-to-ground Multi-target Attack

ZHANG Yu， WANG Nan， CHEN Jing， SHEN Lin-cheng

2011, 32(12):  1474-1480.  doi:10.3969/j.issn.1000-1093.2011.12.008

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A three degrees of freedom (3-DOF) trajectory model for a certain satellite-guided bomb within the atmosphere is built. Then, the methods to solve multi-target launch acceptable region（LAR）are systematically analyzed. Based on the analysis for calculation accuracy and efficiency, a polynomial fitting model is introduced and an improved fast pattern search algorithm is developed for searching the boundary of LAR. The algorithm starts with an approximate initial value obtains from a polynomial fitting function, and can quickly converges toward the extreme value because the initial value is very close to it. The simulation results show that the algorithm is better than the traditional algorithm. Finally, a target set is selected to calculate the multi-target LARs under different initial delivery conditions.

Study on Effect of Random Wind on Proportional Navigation Guidance Precision

XU Ping， WANG Wei， LIN De-fu

2011, 32(12):  1481-1485.  doi:10.3969/j.issn.1000-1093.2011.12.009

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The disturbance effect of random wind on missile is analyzed. A proportional navigation guidance system model with random wind disturbance is built and then simplified．The analytic solution is obtained by using adjoint method. Finally, the original proportional navigation guidance system is analyzed in detail. The analytic solution of the simplified model demonstrates that the miss distance caused by random wind varies as the standard deviation of random wind velocity and trends towards a constant value with the guidance time increase. Simulation results show that the increase of proportion navigation coefficient is beneficial to inhibit the harmful influence of random wind on the guidance precision，either improving autopilot response or reducing the damping coefficient have the same effect.

Cooperative Guidance Strategy in Anti-interception for Target Aircrafts

XIAO Zeng-bo， LEI Hu-min， TENG Jiang-chuan， ZHANG Xu， CHEN Zhi-xiang

2011, 32(12):  1486-1492.  doi:10.3969/j.issn.1000-1093.2011.12.010

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To improve the penetration ability of a target aircraft, a cooperative guidance strategy is proposed based on line-of-sight (LOS) kinematics. Firstly, a interception model is established in which the target aircraft launches a defender missile against an attacker missile. It is proved that the LOS guidance scheme is appropriate for the defender, and the lateral acceleration ratio of defender to attacker is also acceptable. Then, a reverse proportional navigation guidance law is proposed for the target aircraft. It utilizes cooperation between the aircraft and the defender. This guidance strategy can avoid the attacker colliding with the aircraft, as well as make the defender intercept the attacker successfully with no speed and acceleration advantages. The simulation results show that the proposed strategy improves the penetration probability of target aircraft effectively，and can offer a reference for engineering application.

Influence of Operating Conditions on Temperature Distributions of Exhaust Plume of Solid Rocket Motor

WANG Wei-chen， LI Shi-peng， ZHANG Qiao， WANG Ning-fei， WANG Chang-jian， XU Yi

2011, 32(12):  1493-1498.  doi:10.3969/j.issn.1000-1093.2011.12.011

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A coupling calculation model for infrared radiation transfer of plume is built. The radiation source term is induced into energy equation, thus the plume flow field and radiation transfer can be solved in couple. A finite rate model is used to simulate the afterburning phenomenon; a discrete coordinate method is used to solve the radiation transfer equation. The spectral radiation intensity from 1 000 cm^-1 to 4 500 cm^-1 and the radiation intensity contours are obtained. The calculation results concide well with the experiment data. It shows that the motor's operation pressure, the free stream's Mach number and flight height can change the flow structure and temperature distributions of the plume in a extent.

Research on Low Temperature Inspection for Casting Solid Motor’s Liner and Propellant Grain Interface Debonding

YU Guang-hui， LU Hong-yi， WANG Hong-ling， ZHU Min， LIU Hong-yan

2011, 32(12):  1499-1503.  doi:10.3969/j.issn.1000-1093.2011.12.012

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The relationship among debonding clearance, length and freezing temperature of liner and propellant grain in casting solid motor under low temperature is analyzed by using finite element method and visco-elastic theory. The feasibility of low temperature inspection for solid motor’s interfacial debonding is demonstrated theroetically by analyzing the simulation results. Comparing the tested motor’s computed tomography（CT）images before and after freezing, it is proofed that the method of low temperature inspection for solid motor’s interface debonding can partially detect the debonding that can not be detected before freezing.

Research on Structure and Properties of Zr(AlCu)N Erosion-resistant Coatings on Titanium Alloy Surface

DU Jun，ZHANG Ping，ZHU Xiao-ying，CAI Zhi-hai

2011, 32(12):  1504-1509.  doi:10.3969/j.issn.1000-1093.2011.12.013

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Different Zr(AlCu)N coatings are deposited onto titanium alloy TC6 substrates by reactive magnetron sputtering in order to improve the erosion resistance. The morphology and microstructure are studied by using field emission scanning electron microscopy（FSEM）, X-ray diffraction（XRD）and X-ray photoelectron spectroscopy（XPS）. The coatings hardness and toughness are measured by using nano-indentation method and Vickers indentation method, respectively. The erosion rates are measured and the characteristic damage features are identified. The results show that ZrN coating alloyed with Al and Cu can improve the erosion resistance of TC6 effectively. ZrCuN with 20at%Cu can increase the coating toughness by 2 times, whereas because of low hardness, the erosion resistance of ZrCuN can not be improved effectively. ZrAlN with 23at% Al has higher hardness and better toughness, resulting in better erosion resistance than ZrCuN, ZrAlN coating shows brittle erosion feature in erosion test. ZrAlCuN coating with 19at%Al and 2at% Cu has the highest hardness and best toughness, and shows the best erosion resistant performance.

Preparation of Carbon Nanotube/Expanded Graphite Composite Material and Its 8mm Wave Attenuation Properties

ZHANG Qian, JIAO Qing-jie, XUAN Zhao-long, LI Tian-peng, YU Wei-bo

2011, 32(12):  1510-1513.  doi:10.3969/j.issn.1000-1093.2011.12.014

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A kind of 8 mm wave interference composite with high conductivity is prepared by expanding the mixture of multi-walled carbon nanotubes (MW CNTs) and expansible graphite（EG）under the condition of high temperature. The microstructure and electromagnetic properties are characterized by using scan electron microscope (SEM), vibrancy sample magnetometer (VSM) and ohmmeter. The 8 mm wave two dimension static attenuation performances are studied by using the method of test samples. The results show that the tubular structure of carbon nanotubes（CNTs）is changed by the high temperature process and the melting CNTs with membranous shape distribute on the surface and interformational pores of EG; the surface conductivity and electromagnetic wave attenuation increases due to the addition of CNTs，but the diamagnetic characteristic of EG is not changed; the attenuation of electromagnetic wave is mainly caused by the scattering and electromagnetic absorption of the composite; and the 8 mm wave attenuation performance of the composite is better than the pure EG; the 8 mm wave attenuation reaches to maximum (11.68 dB) when the addition weight of CNTs is 29%. With the increase of CNTs, the attenuation performances descend.

Experiment Research on Spectral Properties of Down-conversion Material Ni₂O₃/CuO/Sb₂O₃:SnO₂

LU Yan-li， ZHANG Shuan-qin， JIANG Xiao-jun， PAN Jia-liang

2011, 32(12):  1514-1517.  doi:10.3969/j.issn.1000-1093.2011.12.015

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Takes SnO₂ as main material, intermingles a transition chemical element oxide, a kind of down-conversion powder material absorbing laser at 1.06 μm is prepared by using high temperature agglomeration. The laser absorption characteristic，crystal lattice，surface shape and spectrum down-conversion at 1.06 μm are described. Finally, a coating sample is prepared by using synthesize material, and the laser absorbency at 1.06 μm is measured. The experiment results show that this kind of material has higher laser absorbency at 1.06 μm.

Research on Test Sequence Problem for Multiple Fault Diagnosis

WANG Hong-xia， PAN Hong-bing， YE Xiao-hui

2011, 32(12):  1518-1523.  doi:10.3969/j.issn.1000-1093.2011.12.016

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Aiming at the situation that the weapon equipments take place multiple faults, a test sequence optimal method for the multiple faults is proposed. Firstly, it is explained that some wrong conclusions may be drawn from an example to use the single fault diagnosis strategy to the multiple faults. Secondly, the mapping relationship is established by using the definition of false failure, hitting set and minimal set cover, so that the false failure of all component can be obtained by using the method for solving the set cover. And then, the test algorithm for the multiple faults can be formed by extending the single fault diagnosis strategy，and the extend target is the leaf node containing the hidden failure and false failure. Finally, the validity of the algorithm is illustrated by an example and comparison with other algorithms.

Observation and Analysis of Micro-detonation Arc Machining Process for Engineering Ceramic

ZHANG Bao-guo， TIAN Xin-li， GUO Fang， TANG Xiu-jian₁, WANG Jian-quan

2011, 32(12):  1524-1530.  doi:10.3969/j.issn.1000-1093.2011.12.017

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An experimental system is established to observe and analyze the micro-detonation arc machining（MDAM） process. By means of high speed photography and current signal acquisition, the relationship between the external shape of micro-detonation arc and the working current is studied. The formations of ablation pit in Si₃N₄ and Al₂O₃ are observed by using high speed photography and the surface and cross-section topography are observed by using scanning electron microscape (SEM). The experimental results show that the diameter of micro-detonation arc increases with the working current and the diameter of ablation pit expands with the machining time; Si₃N₄ ceramic can decompose in machining, the surface structure is loosen, and some transverse cracks at subsurface are produced by thermal shock; Al₂O₃ ceramic can directly melt in machining, lots of micro-cracks distribute on the surface, and the main composition of deteriorative layer in grass phase.

Modeling and Analysis of Bullet Discarding Process of Open Link Chain

ZHANG Ben-jun, WANG Rui-lin, LI Yong-jian, HAN Chao

2011, 32(12):  1531-1534.  doi:10.3969/j.issn.1000-1093.2011.12.018

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To analyze the bullet discarding process of open link chain accurately, its finite element calculation formulas were deduced on the basis of contact theory, and then a new method was proposed. By using the new method and finite element model, the bullet discarding process of a machine gun was calculated. Compared with test results, the relative calculation error is 5.4%, and it shows that the method can determine the force of link chair and bullet. Compared with other common used methods, the method proposed in this paper needs not many assumptions for simplification and can obtain more accurate results. The method can offer a reference for the structure optimization of link chair and feed mechanism in weapon, and it can also guide the stress calculation of interference fit problem.

Research Notes

Electromagnetic Vulnerability Test for Guided Weapons Based on Coaxial Current Injection

ZHANG Chi-jun，ZHAO Xue-gang，LIU Hong-yi

2011, 32(12):  1535-1539.  doi:10.3969/j.issn.1000-1093.2011.12.019

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Aims at some troubles in traditional electromagnetic environment effects test method, such as large expense, large antenna size in low frequency and difficult operations, a current injection method is proposed to test the electromagnetic vulnerability（EMV）of guided weapons. The detail theoretical calculation and simulation are carried out and the frequency limitation of the method was given. The method proposed has some advantages, such as low cost, simple operation and is suitable for the electromagnetic effect tests of conventional weapons also.

Effect of Heat Loss Factors on Constant Volume Burner Method

HU Song-qi， XU Qiu-li， LU Jun-nian， WU Su-li， LIU Ying-ji

2011, 32(12):  1540-1546.  doi:10.3969/j.issn.1000-1093.2011.12.020

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The heat loss formula of constant volume burner method is derived. The qualitative research and quantitative analysis of heat loss factors on constant volume burner method is carried out experimentally. The effects of some characteristics of propellant samples, such as pressure-rise rate, burning time, ignition ways, burning rate and so on, on the heat loss behavior are investigated. Results indicate that higher pressure-rise rate, shorter burning time, suitable ignition ways and higher burning rate can possess an excellent ability to reduce the heat loss.

Experiment Research on Properties of Laser Camouflage Material

ZHANG Shuan-qin， LIAN Chang-chun， LU Yan-li

2011, 32(12):  1547-1550.  doi:10.3969/j.issn.1000-1093.2011.12.021

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A theoretical model for laser transmission in atmosphere is established according to the working principle of laser guided weapons， and the requirements for the laser absorption materials are calculated. Some laser absorption pigments with green, grey, black and red colors are synthesized by using high temperature sintering. Three laser absorption paints with deep green, middle green and yellow earth colors are fabricated. A Nd：YAG laser rangefinder is used to measure the laser absorption properties. The measurement results show that laser absorption paints have better properties.

Research on Overall Stability of High Strength Steel Military Bridge Trestle Structure

ZHANG Yin-long, GOU Ming-kang, TAO Li, LI Ning, LIANG Chuan

2011, 32(12):  1551-1556.  doi:10.3969/j.issn.1000-1093.2011.12.022

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One of the research emphases of multi-span military bridge is its trestle structure's stability. Some problems and defects still exist in the present system of stability analysis and design for military bridge trestle structure. By means of large finite element analysis software ANSYS, combined with stability theory of steel rigid or semi-rigid frames, the overall stability of two types of military bridge trestle (portal and stool-like bridge trestle) are studied, and their overall stable ultimate load-carrying capacities are obtained. Comparing with stability test results, it can be seen that the veracity and reliability of the ANSYS simulation is proved. The research is of great significance to the development of military bridge equipments, modification of existing design criterions and improvement of correlative design methods.