Table of Content

31 October 2014, Volume 35 Issue 10

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Paper

Experimental Research of the Thrust of Air-Breathing Pulse Detonation Engine with Central Cone-scales Valve

HU Yan-bin, WENG Chun-sheng, BAI Qiao-dong, YANG Jian-lu, HUANG Xiao-long

2014, 35(10):  1521-1527.  doi:10.3969/j.issn.1000-1093.2014.10.001

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In order to improve the thrust of air-breathing pulse detonation engine, the air-breathing pulse detonation engines with central cone-scales valve (CCSV) and central cone-blunt valve (CCBV) are investigated, and the force condition of multi-cycle air-breathing pulse detonation engine during working is analyzed. The results show that the average thrust of multi-cycle air-breathing pulse detonation engine can be accurately measured by using the piezoelectric force sensor. Furthermore, the average thrust of air-breathing pulse detonation engine with CCSV is 2.05 times as high as that of the engine with CCBV at 10 Hz. For this point of view, the results are significant to the direct measurement of the thrust of multi-cycle air-breathing pulse detonation engine and the improvement of the propulsion performance of air-breathing pulse detonation engine.

Research on Quasi-static Engraving Force of Sniper Rifle Bullet

LIU Guo-qing, XU Cheng

2014, 35(10):  1528-1535.  doi:10.3969/j.issn.1000-1093.2014.10.002

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The engraving process of sniper rifle bullet has a great influence on the firing accuracy of sni-per rifle, which is closely related to the bullet ramp. In order to reveal the effect of bullet ramp on engraving process, a test device is designed for the quasi-static engraving experiments under two different conditions of bullet ramp, and the influence of forcing cone angle on engraving force is obtained. A finite element model is established to simulate the engraving process based on the theory of nonlinear finite element. The simulation results reveal the relationship of forcing cone angle and engraving force, the composition of engraving force, the proportion of each part and the formation mechanism of engraving force, and show that the engraving characteristics of sniper rifle bullet are different from those of other bullets. Furthermore, the engraving process is divided into five parts according to the structures of bullet and bullet ramp, and the formula of each part is derived. The quasi-static engraving process of sniper rifle bullet is studied in three aspects: experiment, simulation and theory, which is helpful in understanding the engraving process of sniper rifle bullet, and the matching mechanism of bullet and bullet ramp.

Research on Penetration Mechanism of Post-Composited Rod

WU Qun-biao， SHEN Pei-hui, LIU Rong-zhong

2014, 35(10):  1536-1541.  doi:10.3969/j.issn.1000-1093.2014.10.003

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A new structure of post-composited rod is designed to improve the penetration ability of rod penetrator. The comparison experiment of post-composited rod and homogeneous rod with the same overall structure invertically penetrating a semi-infinite steel target is conducted. The result indicates that the penetration ability of post-composited rod is superior to that of homogeneous rod. The maximum penetration depth of post-composited rod is 25% more than that of homogeneous rod. The reason of the result is analyzed by the numerical simulation and verified by experimental result. The further simulation of post-composited rod with four different configurations in penetrating a semi-infinite steel target at impact velocity from 1 000 m/s to 1 600 m/s is carried out. The corresponding relationship between the penetration efficiency of post-composited rod with different configurations and the impact velocity is obtained.

Engineering Modeling and Identification of Aerodynamics of Trajectory Correction Projectile with Decoupled Canards

CHENG Jie, YU Ji-yan, WANG Xiao-ming,YAO Wen-jin

2014, 35(10):  1542-1548.  doi:10.3969/j.issn.1000-1093.2014.10.004

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The aerodynamics of trajectory correction projectile (TCP) could be expressed as the function of geometry and flight state, of which model can decide the accuracy of the dynamic system directly. An engineering model suiting for the trajectory correction projectile with decoupled canards (TCPDC) is established based on the results of wind tunnel test. This model, including drag, lift, side force and pitch moment, takes the effects of complex angle of attack (AoA) and the phase angles of canards into account. The least square method is utilized to identify the parameters, and the predicted results are validated by CFD. The results show that the yaw drag caused by canards is relatively small and the error of TCP’s drag fitted by symmetry model is lower than 3.3% within the small AoA. Under the effects of complex AoA and the phase angles of canards, the lift keeps the sinusoidal feature while a secondary sinusoidal vibration arises along the curve of side force for γ_P=180°. The innovative aerodynamic model makes a foundation for the research on TCPDC’s flight characteristics.

Research on the Position Algorithm for Smart Munition Imaging Fuze

HE Xiao-kun, CHEN De-rong, GONG Jiu-lu, LI-Meng

2014, 35(10):  1549-1555.  doi:10.3969/j.issn.1000-1093.2014.10.005

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To measure the relative position between smart munition and vehicle, a location algorithm for imaging fuze based on target geometrical characteristics which are non-cooperative and inherent is proposed. A space imaging model under the fast rendezvous is established to solve the problem, and then the axes of vehicle are defined according to the characteristics of vehicle. The plane consisting of optical center and feature lines across the axes is set up, the parallel relationship among axes and intersecting lines is proved, and the direction vectors of three target-coordinate axes are educed. Based on the direction vectors of target-coordinate axes and the method of undetermined coefficients, a medial plane which includes vehicle’s axes is described by expression. According to the distance constraints from 3D point to plane, the relative position between smart munition and vehicle is resolved by strict derivation. The effect of relative pose on solving error is analyzed, and the error rules are proved by experiments. The experimental results indicate that the relative error of location is less than 5% when the height of smart munition is less than 100 m, and the location algorithm could solve the relative position with high precision.

Study of Physical Simulation Experiment of Penetration Fuze Layer-count Burst Point Control

MAN Xiao-fei， ZHANG He， MA Shao-jie， WANG Xiao-feng

2014, 35(10):  1556-1561.  doi:10.3969/j.issn.1000-1093.2014.10.006

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A method of using the repeated impact machine to simulate the process of hard target penetration is proposed for the physical simulation experiment of hard target penetration fuze. The layer-count algorithm of hard target penetration fuze is introduced. The feasibility of simulating the penetration acceleration signal by use of the impact process is discussed. A simulation experimental system is designed, and a layer-count detonating experiment is done using a certain type of penetration fuze. The result is compared with shooting range test curve, proving the feasibility of the simulation experimental methods. The accuracy of fuze burst point control method can be comprehensively tested. The reliability of fuze moving parts can be testified. Further research is needed as the shock acceleration peak is low and the shock interval is long.

Study of Thermal Stability of HMX Affected by 19-acetoxyl-2468-tetranitro-tetraaza Nonane

LI Li-jie, JIN Shao-hua, CHEN Shu-sen, ZHU Jia-ping, YANG Wei, SUN Lei

2014, 35(10):  1562-1568.  doi:10.3969/j.issn.1000-1093.2014.10.007

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1,9-acetoxyl-2,4,6,8-tetranitro-tetraaza nonane(AcAn) is one of the major impurities of HMX production. It is important to study the thermal stability of HMX affected by AcAn. The geome-trical structure of AcAn is optimized at B3LYP/6-311+G** level and two stable structures are obtained. Bond decomposition energy (BDE) of N—NO₂ of AcAn molecular is calculated at B3P86/6-31G** level, and it is found that N—NO₂ bond adjacent to acetoxy group in the end of AcAn is easy to cleave. The thermal decomposition of AcAn and the thermal stability of HMX affected by AcAn are studied. It is found that the poor compatibility of HMX-AcAn is level 4. The HMX has good stability, but the AcAn has poor stability. The stability of AcAn-HMX mixture of 50wt% AcAn is the worse. HMX product mixed with AcAn has the worse thermal stability and performance. When the content of AcAn in the AcAn-HMX mixture is more than 50wt%, the change of performance of HMX is the biggest. The most probable mechanism function is deduced by double equal double step method, and the thermal decomposition mechanism function is chemistry reaction mechanism. The integral function is g(a)=1-(1-a)^1-n1-n, and the differential function is (a)=(1-a)ⁿ ,n=2.

The Crystal Structure and Theoretical Study of Styphnic/14-dioxane Solvate

CHEN Peng-yuan, ZHANG Lin, ZHU Shun-guan, CHENG Guang-bin

2014, 35(10):  1569-1574.  doi:10.3969/j.issn.1000-1093.2014.10.008

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In order to explore the mechanism of co-crystal explosive formation, styphnic/1,4-dioxane solvate was prepared by solvent evaporation method. This solvate structure was characterized by single crystal X-ray diffraction. Structural analysis shows that O in 1,4-dioxane forms —OH…O strong hydrogen bond with OH in styphnic. Moreover, H in 1,4-dioxane forms CH…O—NO weak intermolecular interaction with nitro group in styphnic. These two kinds of interactions are the main driving force for solvate composing. The Mulliken charge and density of state of both styphnic and styphnic/1,4-dioxane solvate are calculated. The result shows that the nitro group has more negative charge in the solvate than that in the pure styphnate. P orbital plays an important role in the buildup of the solvate and H in styphnate hybridizes with O in 1,4-dioxane.

Preparation of Aluminum Nanoparticles by Liquid Chemical Method and Their Characterization

ZHA Ming-xia, MA Zhen-ye, XU Juan, QIN Hong, XU Si-yu, ZHAO Feng-qi

2014, 35(10):  1575-1580.  doi:10.3969/j.issn.1000-1093.2014.10.009

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Aluminum nanoparticles are tried to be prepared by liquid chemical method to obtain their controlled microstructures. X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and energy dispersive spectrometer (EDS) are applied to characterize the aluminum nanoparticles. The effects of processing parameters including molar ratio of AlCl₃ to LiAlH₄, the adding amount of catalyst and the decomposition temperature on the structure, morphology and composition of the aluminum nanoparticles are studied in detail. The optimal preparation condition is achieved when the molar ratio of AlCl₃ to LiAlH₄ is 1∶6, the adding amount of catalyst is 0.04 mL, and the decomposition temperature is 110 ℃. The obtained aluminum is spherical-like with an average size of 50 nm and contains the minimum impurity elements Cl and Ti.

Biological Treatment of Washing Black Liquid in Refined Cotton Production

JING Xiang-shun, ZHOU Bang-you, GAO Jin-yan, CHEN Min, REN Yong， YUAN Cong-yan

2014, 35(10):  1581-1586.  doi:10.3969/j.issn.1000-1093.2014.10.010

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Washing black liquid is a kind of waste water produced in the pressing and washing processes of refined cotton. Separate treatment of washing black liquid is relatively rare. In order to explore the degree and method of washing black liquid biochemical treatment, the two-stage anaerobic-aerobic and single aerobic processes are used to treat the washing black liquid in the pilot scale of 1 cubic meter per day. The result shows that COD of washing black liquid can be reduced from 1 100 mg/L to 330 mg/L in biochemical treatment. With the coagulation of further aluminum sulfate which optimum dosage is 2.5‰(volume ratio), COD of washing black liquid is decreased to less than 100 mg/L and the chroma achieves less than 50 times. Stench is created by sulfate reduction in the anaerobic treatment process, which decreases the activity of microorganism. Therefore, the washing black liquid is suitable for the direct coagulation treatment of aerobic-aluminum sulfate.

Signal Recognition Technology of Sky Screen Based on Neural Network

LOU Yan, ZHAO Yi-wu, SONG Yu-gui, ZHANG Wei-fang

2014, 35(10):  1587-1594.  doi:10.3969/j.issn.1000-1093.2014.10.011

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The effects of interference factors, such as shock wave of warhead blasting, projectile base shock, aerial birds, insects, vibration, etc.,on sky screen system are analyzed to improve its test accuracy and reliability. The approach of Hopfield auto-associative neural network is used to identify and eliminate the typical interference. The accuracy and reliability of sky screen systemthe is fully validated by analyzing the data from live firing. The results show that, compared with the level signal recognition, Hopfield auto-associative neural network recognition rate can be increased by 17.2% in sky screen test with the 5 bursts in RF/min; Hopfield auto-associative neural network recognition rate is increased by 46.7% in sky screens test of 23 mm caliber armor-piercing shells; under the test condition of firing frequency of 7 500 rounds / minute, the correct signal recognition rate reaches to 93%. In a complex environment, the recognition rate Hopfield neural network algorithm is far higher than traditional level recognition rate，which improve the signal recognition rate and be able to adapt to the complex environmental factors within a region.

Research on Dynamic Response of Launching Site for Missile Unsupported Random Launch

ZHOU Xiao-he, MA Da-wei, HU Jian-guo, ZHONG Jian-lin

2014, 35(10):  1595-1603.  doi:10.3969/j.issn.1000-1093.2014.10.012

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To obtain the dynamic response of launching site, the Hongnestad equation and improved Saenz equation are used to construct the upward and downward stress-strain curves of compressed concrete, which is suitable for asphalt concrete. Damage factor and Sidiroff energy equivalent principle are introduced to establish a plastic damage dynamic constitutive model of launching site for missile unsupported random launch. The dynamic response of the site during launching is analyzed based on nonlinear structural dynamics model considering launching site. The results show that the dynamic response of site below back supports is more significant than that below front support before missile launching. The settlement of site below the bottom of canister launcher is larger, and the sites below the back supports and the bottom of canister launcher are seriously damaged during launching.

Target Tracking Algorithm of Strapdown Homing System Based on Adaptive Tracking Window

GUO Xiao-ran，CUI Shao-hui，CAO Huan，YANG Suo-chang，FANG Dan

2014, 35(10):  1604-1611.  doi:10.3969/j.issn.1000-1093.2014.10.013

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In strapdown imaging homing guidance system, the change of the distance between missile and target and the change of imaging visual angle may cause the rotation and scaling changes of image. The classical mean shift tracking algorithms can not robustly track a target which is under rotation and scaling. A scaling and rotation changing adaptive mean shift target tracking algorithm is proposed. The selected elliptic tracking region model and candidate tracking region model are weighted. Meanwhile, the moment characteristic and Bhattacharyya coefficient of weighted image are used to precisely estimate the actual area of target. Then a covariance matrix which can express the characteristic of image in tracking window is constructed using the estimated area and the second order center moment of weighted image. The relationship between the ellipse area and the eigenvalues of covariance matrix is established by singular value decomposition, the length and orientation of principal axis of ellipse are figured out, and the adaptive change of tracking window is realized. Test results indicate that this algorithm retains the high accuracy and real time of the classical mean shift algorithm, and at the same time, extends the adaptive ability of mean shift algorithm for the changes in scale and rotation of target.

Design and Research of Rolling Missile Autopilot with Pulse Width Modulation Actuator

FAN Shi-peng, LIN De-fu, QI Zai-kang, LU Yu-long, YAO Huai-jin

2014, 35(10):  1612-1618.  doi:10.3969/j.issn.1000-1093.2014.10.014

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Pulse width modulation (PWM) actuator system has been widely used for rolling missile. The application of PWM in control system of rolling missile is studied. The relationship between the autopilot gain and the dynamic characteristics of missile, such as oscillation frequency and damping radio, is described, the characteristic of control coupling resulting from low frequency PWM is mainly analyzed, and the relation among coupling strength, spinning frequency and aerodynamic time constant is discussed. The spectral characteristics of disturbance caused by coupling are obtained by spectral analysis. After modulation, the spectra of guidance and control commands for actuator remain unchanged; however, a high-frequency interference is introduced, which is related to spinning frequency, modulation frequency, and oscillation frequency of missile. Finally, the design criteria for autopilot of the missile are proposed based on the above conclusions. The mathematical simulation and Hardware-in-the-loop simulation results show that the application of PWM in rolling missile is feasible, and the design based on the criteria can reduce the effects of control coupling, and also improve the guidance precision.

Experimental and Numerical Simulation on Deformation and Debonding Processes of HTPB Propellant/Liner Adhesive Specimen

JIANG Ai-min， LI Gao-chun， HUANG Wei-dong， QIU Xin

2014, 35(10):  1619-1624.  doi:10.3969/j.issn.1000-1093.2014.10.015

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In order to obtain the mechanical behavior and failure mode of interface, the uniaxial tension experiments are conducted on HTPB propellant/liner adhesive specimen. The deformation images of various stages are achieved, and the debonding process is observed macroscopically. A cohesive element model is adopted to simulate propellant/liner interface. The results show that the failure mode experiences damage initiation, damage evolution and debonding, and the stress-strain response of adhesive specimen has a distinct nonlinear characteristic. The simulated results of stress-strain response and deformation are consistent with the data obtained from experiment.

Cracking Stress of Composite Ceramic Based on the Boundary Slip of Rod-shaped Eutectics

CHEN Cheng, NI Xin-hua, ZHANG Shu-qin, CHENG Zhao-gang

2014, 35(10):  1625-1629.  doi:10.3969/j.issn.1000-1093.2014.10.016

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According to the organizatinal structure characteristics of eutectic composite ceramics, a prediction model of cracking stress is established, which provides theoretical foundation for analyzing the damage form of composite materials. The matrix of eutectic composite ceramics is mainly composed of rod-shaped eutectics with nano/micron fibers. A small amount of lamellar crystals and spherulites are distributed around the rod-shaped eutectics. Baesd on tensile stress transmitted by strong constraining interphase between fibers and matrix in the rod-shaped eutectics, a load-transmitting model is set up. On the basis of weak constraining interphase characteristics between rod-shaped eutectics or between rod-shaped and crystal particles around the rod-shaped eutectics, the shear stress on the surface of the rod-shaped eutectics is obtained by boundary slip conditions. Considering the random orientation of the rod-shaped eutectics, a theoretical expression of composite ceramic cracking stress is gotten based on the relationship between the applied strain of rod-shaped eutectics and the applied load of composite ceramics as the composite ceramics are subjected to tensile load. The results indicate that cracking stress is closely related to the diameter and volume fraction of nano/micron fiber. The cracking stress increases with the increase in fibers diameter and decreases with the increase in fibers volume fraction.

An Algorithm of Line-spectrum Detection Using Frequency Domain Phase Compensation with Difference and TPM Technique

DAI Wen-shu, CHEN Ya， CHEN Xin-hua, SUN Chang-yu, YU Hua-bing

2014, 35(10):  1630-1637.  doi:10.3969/j.issn.1000-1093.2014.10.017

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The common average power spectrum estimation algorithm may cause the loss in detection performance because power spectrum amplitude is simply squared. The statistical properties of FFT of the segmented observations are analyzed, and a novel algorithm using frequency domain phase compensation for detecting line-spectrum in Gaussian noise is proposed. The phase compensation factor is estimated using Monte Carlo method. The sporadic and continuous outliers are removed by using difference and TPM method. Finally the statistics is checked by using generalized likelihood ratio. The detection performances of AVGPR, GPR and the proposed algorithm are theoretically compared. The simulation results show that the detection performance of the proposed algorithm is improved by 5 dB under a certain false alarm rate compared to AVGPR algorithm. It fully utilizes the phase information of the signal and has the advantages of simple and exact parameter estimation and good robustness.

GPU-accelerated Magnetic Moment Method for Magnetic Signatures of Ship

GUO Cheng-bao, LIU Da-ming

2014, 35(10):  1638-1643.  doi:10.3969/j.issn.1000-1093.2014.10.018

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Magnetic moment methods (MMMs) are particularly well suited to model the magnetic signatures of the ferromagnetic objects, such as ship, because they do not require the meshing of non-ferromagnetic materials like air. However the methods need the storing and solving of a fully dense matrix system. Computation takes a long time, and a large storage space is reqiured for storing the matrix. The method based on MMM and multilevel adaptive cross approximation (MLACA) leads to a significant reduction of the required memory and computation times. But the computation times are still too long for the resolution of very fine meshed geometries. The graphical processing units (GPU) with high parallel processing capability is used to accelerate MLACA with the natural parallelism, and the parallel computation strategies are presented, implementing the fast analysis of large scale MMM for magnetic signatures of ships. The results of typical examples indicate that the speedup ratio of the parallel computation of graphics processing unit (GPU) is more than 120, and the computation time for the ship hull finely meshed to 100 000 sheet elements is only about 4.3 min. The difference between the calculated results of the proposed method and the FEM commercial software is less than 1%. Thus, it provides a fast, accurate and simple method for the large scale modeling of ship magnetic signatures．

Modeling and Optimization on Antiaircraft Weapon-target Assignment at Multiple Interception Opportunity

ZHANG Jiao， WANG Zhong-xu， CHEN Li， WU Zhao-bin， LU Jian-feng

2014, 35(10):  1644-1650.  doi:10.3969/j.issn.1000-1093.2014.10.019

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In antiaircraft weapon-target assignment, the weapon resources could be wasted if all weapons are fully assigned at a time. In view of this situation, a weapon-target assignment model of multiple interception opportunity is proposed. The model is used to screen the weapon groups for multiple interception based on flying time of target approaching to a weapon unit, and the weapon units in the weapon group intercept the target according to the time order. The model not only optimizes the target damage probability, but also considers the consumption of weapon resources. Based on the model, a mixed chaos and discrete particle swarm optimization algorithm is presented to solve the weapon-target assignment problem. The proposed algorithm improves the seeking ability for the global optimal solution so that the local extremum is avoided. Simulation results show the rationality of the weapon-target assignment model and the effectiveness of the proposed mixed optimization algorithm, which is a new thought for antiaircraft weapon-target assignment.

Vibration Cutting Analysis of Axially Moving Diamond Wire Saw Excited by Transverse Ultrasonic Wave

LI Lun， LI Shu-juan， Tang Ao-fei， LI Yan

2014, 35(10):  1651-1658.  doi:10.3969/j.issn.1000-1093.2014.10.020

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The diamond wire saw has been widely used in cutting the hard and brittle materials, such as Si and SiC single crystals, because of its narrow kerf and great flexibility. The ultrasonic vibration has a unique benefit in cutting the ultra-hard and brittle materials. Based on the analysis of vibration model of axially moving string, the expressions of transverse vibration displacement field in which the wire saw is excited in different positions by ultrasonic wave are solved by applying the separation-of-variables method, and the expression of system natural frequency is obtained, too. The effect of wire saw system parameters on natural frequency is discussed. The critical speed of wire saw is analyzed. The relation among the midpoint amplitude of wire saw excited by ultrasonic wave when wire saw reciprocatedly cuts and the parameters of wire saw system is analyzed. It is proposed that the feed speed of workpiece is a decisive factor affecting cutting mode of wire saw excited by ultrasonic wave. Doppler laser vibrometer is used to measure the natural frequency of wire saw, the vibration response frequency of wire saw excited by ultrasonic wave, and the frequencies of wire saw in different positions when wire saw cuts SiC ingot with ultrasonic vibration. Comparative experiments of cutting SiC are carried out with and without ultrasonic vibration.The result shows that cutting forces is reduced by 23%～38% with ultrasonic vibration cutting, and the quality of the cut surface is improved obviously. The measurement and experimental results are consistent with the analysis results of model.

Estimation of Model Parameters and SOC of Lithium Batteries Based on IPSO-EKF

XIANG Yu， MA Xiao-jun， LIU Chun-guang， KE Rong-shuo， ZHAO Zi-xu

2014, 35(10):  1659-1666.  doi:10.3969/j.issn.1000-1093.2014.10.021

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An extended Kalman filter (EKF) which is optimized by the improved particle swarm optimization (IPSO) algorithm is proposed to estimate the state-of-charge (SOC) of battery. A new state space equation applied to EKF algorithm is constituted to reduce the influence of non-linear characteristics of parameters, and the optimal estimation of SOC is obtained based on the real-time identification of battery model parameters. IPSO algorithm is applied to optimize the system state error covariance matrix and measurement noise covariance matrix to improve the estimation accuracy of SOC by solving the problems in achieving the optimal solutions of these covariance matrixes. The results show that the IPSO-EKF algorithm can estimate the model parameters and SOC of battery accurately, and correct the state variable initial error.

Study of Jet Ignition of Methane in a Divided Constant Volume Combustion Bomb

LIU Hao, ZHANG Hong-guang, ZHAO Guang-yao, BAI Xiao-lei, WANG Zhen, SUN Na

2014, 35(10):  1667-1673.  doi:10.3969/j.issn.1000-1093.2014.10.022

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In order to improve the methane-air mixture combustion rate, the experiment of a divided constant volume combustion bomb is carried out for fast burning of methane-air mixture by jet ignition. The effects of baffle plate parameters, such as location, orifice diameter and orifice number, on fast burning of methane-air mixture by jet ignition under various initial conditions are studied by means of schlieren method. The experimental data of constant volume combustion bombs with and without single and plural orificed baffle plates are compared. The results show that the combustion rate is improved by an orificed baffle plate. The location C in the constant volume combustion bomb is the best place since the main combustion chamber is easy to burn under certain experimental conditions. The peak combustion pressure of the methane- air mixture increases first and then decreases with the increase in the diameter and number of orifices.

Effect of CeO₂ Modified Woven Liners on Film-forming Mechanism of Self-lubricating Spherical Plain Bearings

QIU Ming， MIAO Yan-wei， LI Ying-chun

2014, 35(10):  1674-1680.  doi:10.3969/j.issn.1000-1093.2014.10.023

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The performances of liners of hybrid polytetrafluoroethylene (PTFE)/kevlar fabrics are modified by CeO₂. The tribological properties of self-lubricating spherical plain bearings are test on the spherical plain bearing tester under continuous swaying condition with a swaying frequency of 2.5 Hz and a swaying angle of ±10°, and the film-forming and wear mechanism of the bearing are analyzed by observing the worn surfaces with scanning electron microscope (SEM), energy dispersive spectrometer (EDS), and X-ray photoelectron spectroscopy (XPS). The results show that the tribological properties of the bearings modified by CeO₂ are much more improved compared to the unmodified bearings, especially the effects of improving the wear resistance and preventing the temperature from rising are remarkable. The reason is that a relatively stable PTFE transfer film forms in a short time on the worn surface of the liner modified by CeO₂, which has good smoothness, thickness uniformity and wear resistance ability. There are slight adhesive and abrasive wears on the modified bearing liners , but there are serious adhesive and abrasive wears on the unmodified bearing liners.

Blind Source Separation of Mechanical Fault Based on Quantum Genetic Algorithm

LI Zhi-nong, PI Hai-yu, XIAO Yao-xian

2014, 35(10):  1681-1688.  doi:10.3969/j.issn.1000-1093.2014.10.024

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For the deficiency in the blind separation method of mechanical fault sources based on the genetic algorithm, which is named as GA-BSS method, and the unique advantages of quantum genetic algorithm, a blind separation method of mechanical fault sources based on the quantum genetic algorithm, which is named as QGA-BSS method, is proposed. The proposed method is compared with the traditional GA-BSS method. The simulation results show that the QGA-BSS method is superior to the traditional GA-BSS method, especially in the convergence speed. The proposed method avoids the premature convergence in the GA-BSS method and greatly reduces the amount of calculation. Finally, The proposed method is applied to the separation of bearing fault, and can extract the bearing fault features from the mixture signals successfully .The experimental results prove that the proposed QGA-BSS method is effective.

Failure Prediction of Missile Equipment Based on Data Fusion and AMUGM(11) Model

ZHAO Jian-zhong， YE Wen， ZHANG Lei

2014, 35(10):  1689-1695.  doi:10.3969/j.issn.1000-1093.2014.10.025

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In view of the unequal data sampling time interval, the great difficulty of date sampling and a small amount of data in failure prediction of missile equipment, a prediction method based on data fusion and amendatory metabolism unequal interval grey model (AMUGM(1,1)) is proposed according to data fusion technology and grey prediction theory. The unequal interval grey model (UGM(1,1)) is established by improved initial value choice and background value constitution, and is optimized by residual error correction and metabolism．Then a membership grade weighted method is put forward based on weighted idea so as to determine the membership values of the models. Finally, a failure prediction model of special individual is built on the basis of membership values and AMUGM(1,1) model. The simulation result shows that the proposed method is effective.

Comprehensive Review

An Overview of Research on Military Unmanned Ground Vehicles

CHEN Hui-yan, ZHANG Yu

2014, 35(10):  1696-1706.  doi:10.3969/j.issn.1000-1093.2014.10.026

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Unmanned ground vehicles (UGVs), which are of great strategic significance for developing high maneuvering unmanned ground combat systems, have become a research hotspot of defense technology. The development and current progress of UGVs for military application are reviewed. The fundamental components and development characteristics of military UGVs are stated and analyzed. The key technologies of military UGVs are also summarized in the areas of sensing and perception, motion planning and path tracking. In addition, the future research direction and focus of military UGVs are suggested.

Research Notes

Slip Ratio Control of Locomotion System Based on Sliding Mode Variable Structure Control

HUANG Yu-xin， WANG Tong-yu， LIN Lin

2014, 35(10):  1707-1715.  doi:10.3969/j.issn.1000-1093.2014.10.027

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The running parameters of lunar rover locomotion system often varies during running. The traditional control method cannot be used to gain the optimal control effect in any case. The variable structure control with sliding mode (VSS) is a special non-linear control method and has strong robustness. The method is easy to be realized. The control logic and algorithm of lunar rover slip-ratio control are established based on the dynamic model of lunar rover and the variable structure control system with sliding mode theory. The control characteristics of VSS are analyzed in details. VSS is applied in slip-ratio control of the lunar rover locomotion system successfully. The simulation is conducted. The simulation results show that the control method has good control effect.

Analysis on Influence of Coordinate System Selection on Artillery Combat

ZHANG Wei-min, MA Hong-wei, LIANG Jian-qi, WANG Tong

2014, 35(10):  1716-1720.  doi:10.3969/j.issn.1000-1093.2014.10.028

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The differences among the gun-target distances and directions calculated using the space geodetic coordinate system and the Gauss plane rectangular coordinate system are quantitatively analyzed, and the influences of BJS54 and CGCS2000 on distance calculation accuracy are also analyzed. The results show that, due to projection distortion, the gun-target distance error calculated using the Gauss plane rectangular coordinate system is up to 1‰, and the gun-target direction error is larger at a farther gun-target distance. When BJS54 and CGCS2000 are used to calculate the gun-target distance, the difference between the calculated results is less than the actual distance of 0.05‰, which can be ignored.

Evaluation of Air-defense C⁴ISR System Structure Based on Discrete-event Simulation

DENG Ke-bo, CHENG Wen-di, LEI Ming, RAO Jia-ren

2014, 35(10):  1721-1728.  doi:10.3969/j.issn.1000-1093.2014.10.029

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An approach to evaluate the air-defense C⁴ISR system in the consideration of relationship between communication network and information is proposed based on the discrete-event simulation. Various kinds of discrete events in the air-defense C⁴ISR are defined, and the event processing flows, logic relations and common basic data are presented. The evaluation indexes and their computation models are constructed for the air-defense C⁴ISR system, and some experiments are implemented to prove the effectiveness of the proposed method, in which the target detection probabilities and assignment rates of C⁴ISR systems with tree and network structures are compared in the same scenario.