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Table of Content

    01 April 2013, Volume 34 Issue 4
    Residual Stress Analysis of Gun Barrel with Bi-linear Material Model
    CHANG Lie-zhen, PAN Yu-tian, LI Kui-wu, MA Xin-mou
    2013, 34(4):  385-391.  doi:10.3969/j.issn.1000-1093.2013.04.001
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    To derive the residual stress of swage autofrettage gun barrel with elastic perfectly-plastic linear hardening material model, the elasticity and plasticity of barrel during loading and unloading are analyzed based on the theory of elastic-plastic mechanics and some assumptions. And the formulas of plastic radi- us, loading and unloading stress-strains, and reverse yielding radius of swage autofrettage gun barrel are derived. The residual stress formulas with and without reverse yielding are obtained by using loading and unloading stresses of gun barrel, respectively. In order to verify the accuracy, the plastic radius, reverse yielding radius and residual stress of barrel are calculated by using the presented formulas. The results show that the theoretical values are good agreement with the experiment results.

    Dynamics Analysis of Structure and Positioning Control of an Ammunition Coordinator
    GUO Yu-fei, HOU Bao-lin
    2013, 34(4):  392-397.  doi:10.3969/j.issn.1000-1093.2013.04.002
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    A novel 2-DOF ammunition coordinator structure scheme is proposed, and the controlled dy- namics behavior of the coordinator is studied by considering the influence of the random vibration of its in- stallation base. The random vibration of base is treated as one kind of external disturbance forces acting on the coordinator, and the action of the coordinator on the base is negligible. On the assumption that the external disturbance force and the control force are bounded, a nonlinear control algorithm and the struc- ture-control coupling dynamics equations of the coordinator are established based on the second kind La- grange equations and a special implicitly given Lyapunov function. The dynamics equations are solved by a numerical algorithm based on Newton's method and the Runge-Kutta method. The simulation result shows that the proposed 2-DOF ammunition coordinator can be used to realize the accurate coordination and positioning control of the ammunitions.

    Research on a Method of Measuring the Impact Location Dispersion of Double Barrel Cannon Based on the Seven-light-screen Array
    NI Jin-ping, LU Hong-wei, TIAN Hui
    2013, 34(4):  398-405.  doi:10.3969/j.issn.1000-1093.2013.04.003
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    In order to meet the demand of measuring the impact location dispersion of a double barrel canon automatically, the principle of the seven-light-screen array was put forward. The seven-light-screen array can be set up by adding a light screen in the middle of the double 吁type six-light-screen array. Based on the principle of that the firing position is on the corresponding projectile ballistic line, an algo- rithm of identifying the time sequence of the same projectile going through the seven-light-screen array was identified. The method was simulated and verified on MATLAB. The results show that the method is feasible and it can be used to measure the impact location dispersion parameters of the double barrel can- on.

    A Video Stabilization Method Based on Sub-block Gray Projection
    WU Hao, DENG Hong-bin
    2013, 34(4):  406-411.  doi:10.3969/j.issn.1000-1093.2013.04.004
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    A video stabilization method based on sub-block gray projection algorithm is proposed. Firstly, each image is divided into sub-blocks which are filtered according to their gray gradients. After the sub- blocks of which gray gradients are lower than a threshold are removed, the calculation amount of projec- tion is reduced and the motion estimation accuracy is improved. Then gray projection is done in the re- mained sub-blocks, and the global motion vector is calculated according to the local motion vectors and the interframe motion model. Finally, the trembling image is compensated to stabilize the image sequence according to motion compensating vector. The problems of that the global motion estimation accuracy is reduced by the local motion and the rotation motion of camera could not be estimated by traditional gray projection algorithm are effectively resolved by the sub-block gray projection algorithm. The experiment results show that the algorithm is more accurate and efficient than the traditional gray projection algo- rithm.

    Camouflage Assessment Method Based on Image Features and Psychological Perception Quantity
    LIN Wei, CHEN Yu-hua, WANG Ji-yuan, SU Rong-hua, YU Song-lin
    2013, 34(4):  412-417.  doi:10.3969/j.issn.1000-1093.2013.04.005
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    Detection probability is an important index of camouflage assessment. Based on statistical deci- sion model, the relationship between single image feature and psychological perception quantity is set up by defining the similarity of four image features. Five psychological experiments were carried out, and the relation between perception quantity and detection probability was found. The verification of target inter- pretation shows that the target detection probability can be obtained by the model objectively. A new method is provided for camouflage assessment.

    Analysis of Ultraviolet Radiation Characteristics of Liquid Propellant Rocket Motor Exhaust Plumes
    GUO Ai-yan, BAI Ting-zhu, HAN Qiang, TANG Yi
    2013, 34(4):  418-424.  doi:10.3969/j.issn.1000-1093.2013.04.006
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    Through the analysis of ultraviolet radiation mechanism of liquid propellant rocket motor ex- haust plumes, a rocket motor plume ultraviolet radiation model was build, taking thermal emitting, CO + O chemiluminescence and OH radical chemiluminescence into consideration. Based on the separate cal- culation of flowfield and radiation transfer, the flowfield and radiation intensity distribution can be solved using 2-D and 3-D grids, respectively, which can save the computation time and get both of the spectrum of radiation intensity and the radiance at different angle of view distribution. The ultraviolet spectral radi- ation intensity as well as the two-dimensional radiance distribution at 90毅angle of view of liquid hydro- gen/ liquid oxygen and kerosene/ liquid oxygen bipropellant rocket motor plumes were calculated using the rocket motor plume ultraviolet radiation model, respectively. The influence of mixture ratio on ultraviolet radiation distribution of liquid bipropellant rocket motor plumes was studied by taking liquid hydrogen/ liquid oxygen as an example. This study can provide reference for the analysis, design and optimization of ultraviolet early warning system, the judgment of missile types in the process of early warning, and the evaluation and improvement of missile ultraviolet stealth performance.

    Surface Temperature Field of Projectile Flying at High Rotational Speed in Exterior Ballistic
    ZHANG Jun, LIU Rong-zhong, GUO Rui, QIU He, LIU Meng-meng
    2013, 34(4):  425-430.  doi:10.3969/j.issn.1000-1093.2013.04.007
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    To get the surface temperature characteristics of projectile flying at high rotational speed, based on the six degree of freedom (6-DOF) rigid body trajectory model, the heat balance equations were established by using node thermal network method. With the heat exchange theory of flow around a cylin- der, the influence of rotation was considered for the calculation of aerodynamic heating. The temperature field distribution under the control of trajectory data and airflow properties was obtained by solving the trajectory equations and the heat balance equations simultaneously. Finally, the factors which have im- pact on the surface average temperature field, including launching velocity, initial rotational speed, launching angle and airflow temperature, were also studied. The results show that the surface temperature increases with launching velocity non-linearly. The temperature gradient is inversely proportional to the distance from the warhead. The bigger the initial rotational speed is, the higher the peak temperature and the rate of temperature change are. The higher the airflow temperature is, and the smaller the launching angle is, the higher the average temperature is.

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    QIAO Yang, XU Xi-ping, GU Yi-wen, PAN Yue, ZHANG Xiao-yu
    2013, 34(4):  431-436.  doi:10.3969/j.issn.1000-1093.2013.04.008
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    Numerical Calculation of Infrared Radiation Characteristics of the Exhaust Plume Outside a Rectangular Nozzle
    FENG Yun-song, LI Xiao-xia, LU Yuan, JIN Wei
    2013, 34(4):  437-442.  doi:10.3969/j.issn.1000-1093.2013.04.009
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    For mastery of infrared radiation spectral characteristics and intensity distribution of exhaust plume of a rectangular nozzle, a geometrical model of a rectangular nozzle was established. Software Flu- ent6. 3 was used to simulate the 3-D exterior flow field of the rectangular nozzle, and the data of the flow field, such as temperature, pressure and density, was obtained, and the computational area of infrared radiation was established according to the characteristics of the rectangular nozzle plume. A statistical narrow-band model with Lorentzian profile was used to obtain the mean absorption coefficients of the plume in a narrow band. Then Finite Volume Method was used to solve the radiative transfer equations with gas medium. Finally, the spectral characteristics and the total intensity distribution in 3 ~5 滋m of exhaust plume radiation were obtained. The results show that the plume is flat, the infrared radiation in- tensity on the symmetry surface of wide side is greater than that of narrow side, and two peaks of plume infrared radiation emerge in 2. 7 滋m and 4. 3 滋m.

    Underwater Vehicle Control Method Based on Nonlinear Dynamic Inversion
    CUI Nai-gang, BAI Yu-liang, CHANG Ya-wu, WANG Xiao-gang, XU Jiang-tao
    2013, 34(4):  443-450.  doi:10.3969/j.issn.1000-1093.2013.04.010
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    To be aimed at the characteristics of the underwater vehicle which has a strong nonlinearity, strong coupling, multiple input and output, complex hydrodynamic action and attitude changes severely, a nonlinear dynamic inversion control system is designed in this paper to solve the limitations caused by ignoring the nonlinear factors in the linear process of the design method of the traditional controller. Through the design of the slow loop attitude controller and the fast loop attitude controller, the problems that the underwater vehicle has nonlinear, strong coupling, multiple input and output are solved,the sta- bility of controller have been proven by Lyapunov stability analysis. The steady-state time is 1s and the o- vershoot is 4%by tracking unit step signal in this control method, it has a larger increase than the dynam- ic characteristics by PID control. The results of nonlinear control system simulation show that the control- ler for the uncertainty of 依30% hydrodynamic parameters has certain robustness.

    Research on Efficient Software Component Framework for Embedded Distributed Computing Environment
    CAO Jing-yu, CHAI Wei-yan, WANG Bo, GUO Yong-hong
    2013, 34(4):  451-458.  doi:10.3969/j.issn.1000-1093.2013.04.011
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    In order to overcome the shortcomings of traditional EJB, CORBA, and publish/ subscribe middleware software architecture, an efficient software component framework suitable for embedded dis- tributed computing environment is proposed. The software architecture is based on the open service gate- way initiative(OSGi)standard, and can be used in multi-communications protocol environment by adding a transmission abstraction layer. It is characterized by versatility, high stability and less memory foot- print. The experimental results show that the software is superior to the traditional software architecture in memory footprint, startup time and service interface response time. It can meet the harsh conditions of the embedded environment.

    Research on Power System of Hydraulic Catapult Mechanism
    ZHAO Wei, RUAN Jian, LI Sheng, PEI Xiang
    2013, 34(4):  459-464.  doi:10.3969/j.issn.1000-1093.2013.04.012
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    A hydraulic power system design was proposed to achieve a hydraulic catapult, which mainly consists of a high-speed hydraulic cylinder, a piston accumulator, a main valve and a servo valve. An in- genious cylinder cushion structure was designed to avoid strong shock and vibration at the stroke end of hydraulic cylinder piston. The system working principle and design method were discussed. Then a sys- tem mathematical model was established, and the characteristics of the catapult and cushion process were further investigated through numerical simulation. Theoretical results were finally compared with the ex- perimental ones, and it was found that they are in agreement. The results show that the moving speed of hydraulic cylinder piston is up to 7 m/ s within 70 ms, and the cushion efficiency reaches 95% within 12 mm cushion stroke of hydraulic cylinder piston.

    Simulation Experiment Study on Elliptical Ultrasonic Vibration Boring of Leading Bushing
    ZHANG Cheng-mao, ZHANG De-yuan
    2013, 34(4):  465-470.  doi:10.3969/j.issn.1000-1093.2013.04.013
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    Most research on elliptical ultrasonic vibration cutting is without leading bushing in present, in this paper, the elliptical ultrasonic vibration cutting device with leading bushing is studied. Based on the analysis of elliptical ultrasonic vibration cutting mechanism, cutting experiments were done. The results show that elliptical ultrasonic vibration cutting device with leading bushing can still make the cutting forces decrease remarkably, and improve the machining accuracy. The average thrust force and principal force of elliptical ultrasonic vibration cutting value drop to 19. 6% and 31% of conventional cutting. When the theoretical depth of cut is 0. 050 mm,the actual depth of elliptical ultrasonic vibration cutting is close to the actual depth of cut and the value is 0. 045 mm. There are large difference between conven- tional cutting and theoretical depth of cut, the actual value is 0. 032 mm.

    Research Notes
    Research on Adaptive Internal Model-based Output Regulation Problem in a Shipborne Rocket Laucher
    ZHUANG Wen-xu, MA Da-wei, ZHANG Long, HU Jian, ZHENG Ying
    2013, 34(4):  471-476.  doi:10.3969/j.issn.1000-1093.2013.04.014
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    To reject the disturbance from oscillating ship deck in a shipborne rocket launcher control sys- tem, a mathematical model of the integrated system based on permanent magnet synchronous motor (PMSM) was established, and the internal model-based output regulation problem (ORP) was studied. The deck motion was modeled as the superposition of a fixed number of sinusoidal functions of time, and of unknown frequency, amplitude and phase. An adaptive scheme based on the tracking error and the states of the internal model controller was designed, which is robust with respect to uncertainties on the mechanical parameters that characterize the model and the exosystem. Simulation results demonstrate that the proposed control strategy performs well in solving ORP of rejecting the disturbance coupling from rock- et fixed deck, and the tracking error is exponentially asymptotically stable at the origin.
    Robust Adaptive Backstepping Control for Rocket Launcher Position Servo System with Constraint Control
    WU Yue-fei, MA Da-wei, LE Gui-gao
    2013, 34(4):  477-483.  doi:10.3969/j.issn.1000-1093.2013.04.015
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    An adaptive robust controller based on dynamic filtering method is presented for the wide vari- ations in rotational inertia and loading moment and the input control constraints of a rocket launcher posi- tion servo system. A projection-type estimation algorithm is used to estimate the uncertainties of model, the design of the controller is simplified by using a robust sliding model filter, meanwhile an auxiliary a- nalysis system is utilized to handle a saturation problem, Besides, the auxiliary analysis system is com- bined with the backstepping method, a design method of controller is presented by equivalently transfor- ming the model and selecting a proper Lyapunov function. The simulation results show that the proposed approach can guarantee the response speed and control accuracy, and possess a strong robustness to both parameter perturbation and load disturbance.
    Method of Double Degrees of Freedom Backstepping Control for Position Tracking of Rocket Launcher
    MA Wu-ning, XU Chen, GUO Ya-jun
    2013, 34(4):  484-489.  doi:10.3969/j.issn.1000-1093.2013.04.016
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    A double degrees of freedom backstepping control method is proposed for large variation in load, strong disturbing torque due to launching and high tracking accuracy requirement. Control law is designed by deriving iteratively according to the mathematical model of servo system. Degree of freedom factor is used to adjust the control parameters, and the closed-loop controlling system is proved to be sta- ble through Lyapunov function. The simulation study of the position tracking under the conditions of ex- ternal disturbance and parameter perturbation was carried out, and the constant-velocity and sine-velocity tracking performances were experimentally analyzed. The simulation and experiment results show that the proposed approach can guarantee the response speed and control accuracy and has a strong robustness to the load disturbance and parameter perturbation.
    Research on Precision of Ballistic Coordinates of Trajectory Correction Projectile Launched from Shipborne Gun
    HUANG Yi, WANG Hui-chuan, LI Tie-peng, YU Jia-xiang
    2013, 34(4):  490-493.  doi:10.3969/j.issn.1000-1093.2013.04.017
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    The warship continues to move after the trajectory correction projectile is fired from shipborne gun, and the shipborne radar for trajectory measurement also continue to move and sway, and so the rela- tive trajectory measured by radar need to be transformed into the ballistic reference frame which takes the gun muzzle as an origin during firing. The precision of transformed ballistic coordinates is influenced by the warship fluctuation and the errors of radar measuring, warship sway angles, velocity and course bear- ing. In order to quantify the influence of every error on the precision of ballistic coordinates, a model of precision of ballistic coordinates was set up and simulated, and some data about the influence of warship fluctuation and the errors of radar measuring, warship sway angles, velocity and course bearing on the precision of ballistic coordinates were got.
    Estimation of Motion Parameters by Considering the Size of Surface Target
    SHI Jie, QI Guo-qing, SHENG An-dong
    2013, 34(4):  494-500.  doi:10.3969/j.issn.1000-1093.2013.04.018
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    Target tracking performance of surface particle target tracking system for position measurement of traditional two-dimensional coordinates is hardly improved on condition that no extra prior information is added. Based on engineering application, a ship was modeled as an elliptical target by considering the dimensions of the surface target, and the shape parameters of elliptical target were attained by a mature image processing technology. Meanwhile, an algorithm for estimating the motion parameters of elliptical target based on nonlinear measurements was presented; and the Cramer-Rao low bound (CRLB) of mo- tion parameter estimation was analyzed for the different parameters of target shape. Simulation analysis and preliminary results show that the elliptical target tracking is feasible, the elliptical target tracking sys- tem converges faster than the particle one, and the accuracy of motion parameter estimation of the ellipti- cal target system is higher than that of the particle system.
    An Improved Color Separation Method for Object Detection in Complex Background
    WU Qing-qing, XU Ting-fa, YAN Hui, XU Lei, WU Wei, LI Xiang-min
    2013, 34(4):  501-506.  doi:10.3969/j.issn.1000-1093.2013.04.019
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    An improved background subtraction algorithm based on color separation method is introduced to solve the problem of high rate of missing detection of moving object in complex background. First, the current and background color images are individually divided into three images according to RGB chan- nels. Then the background subtraction is made, and the object with threshold in every channel is seg- mented. After that, three result images are combined to obtain a completed foreground image. Edge sub- traction result is used to fix the foreground image so that the noise brought by light is removed. At the same time, the background image from each channel is updated adaptively, in real time and individually. The results show that this method can effectively detect the difference of color which cannot be found by tranditional method because of similar grayscale in complex background.
    Analysis of Overall Accuracy of Mast-mounted Photodetection System
    CHEN Zhao-bing, WANG Bing, CHEN Ning, SHI Kui, LIU Chang-shun
    2013, 34(4):  507-512.  doi:10.3969/j.issn.1000-1093.2013.04.020
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    A method of how to uniformly distribute the accuracy on the azimuth direction of the optic- electronic system and mast platform system is put forward. This method is used to distribute and analyze the accuracy of the mast-mounted photodetection system. The overall accuracy index is separately distrib- uted to photodetection system and mast platform system. This accuracy distribution is calculated based on the system parameters to prove whether it could satisfy the accuracy requirement. The rationality of accu- racy distribution approach of the mast-mounted photodetection system is validated through infield experi- ment. The calculated and experiment error values of azimuth direction of the photodetection system are 1. 2义and 1. 9义, respectively, which are less than 2义. The calculated and experiment error values of azi- muth direction of the mast platform system are 19. 7义and 23. 5义, which are less than 24义. The overall cal- culated and experiment error values of the system are less than 25义.