Table of Content

28 February 2018, Volume 39 Issue 2

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Contents

2018, 39(2):  0. 

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Paper

Flow and Pressure Compound Control Strategy for Missile Hydraulic Erection System

FENG Jiang-tao, GAO Qin-he, SHAO Ya-jun, QIAN Wen-xin

2018, 39(2):  209-216.  doi:10.3969/j.issn.1000-1093.2018.02.001

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The load of missile erection system is time-varying and an excessive load exists. When the closed or open loop control method is used, the control accuracy is low, and a large hydraulic impact is easily generated in starting-braking process. An independent metering technology is proposed to control the erection process. The inlet and outlet of hydraulic cylinder are controlled by two independently adjustable throttle valves, respectively. The inlet throttle valve is used to control the flow of inlet, and the outlet throttle valve is used to control the pressure of outlet. The flow and pressure controllers are designed based on computational flow feedback and pressure closed loop, respectively. Flow and pressure compound control strategy was achieved. Experiment of the control strategy was accomplished. Through comparison with displacement closed loop, it is shown that the flow and pressure compound control method is used to reduce the hydraulic impact and improve the control precision of erection system. Key

Research on the Effect of Diesel Injector Nozzle Deposit on Spray Characteristics of Diesel Engine

ZHAO Wen-zhu， WANG Xian-cheng， ZHAO Yong-dong， SUN Zhi-xin， XU Dong-dong

2018, 39(2):  217-223.  doi:10.3969/j.issn.1000-1093.2018.02.002

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An internal flow model is established based on the size and distribution characteristics of diesel injector nozzle deposit. The effect of nozzle deposit on internal flow is calculated by the way of VOF (volume of fluid) method. A constant volume spray model is established based on KH-ACT breakup model and the calculated result of coupled internal flow. The effect of nozzle deposit on spray characteristics is calculated. The internal flow model and spray model are verified through the injection flow-rate and spray tests on the fuel injection pump test bench. The research results show that the internal deposit could result in reducing the internal flow velocity, weakening the cavitation effect, and decreasing the penetration distance and the Sauter mean diameter (SMD). The outlet deposit leads to an increase in the internal flow velocity and the enhanced cavitation effect, whereas its effect on penetration distance is small. The SMD increases in the early stage of injection, and the change of the late stage is small. Key

In-plane Rigid-elastic Coupling Dynamic Modeling and Vibration Response Prediction of Heavy Duty Radial Tire

LIU Zhi-hao， GAO Qin-he， LIU Zhun， WANG Xu

2018, 39(2):  224-233.  doi:10.3969/j.issn.1000-1093.2018.02.003

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A rigid-elastic coupling model is established and the vibration analysis method is presented for researching the in-plane characteristic of heavy duty radial tire with aspect ratio of about 1. The experimental modal test and analysis methods of coupling between carcass and sidewall are proposed, and the coupled natural frequencies are analyzed with the normal pressure and fixed rim. The rigid-elastic coupling equation is modeled with the flexible beam on the foundation that the carcass is modeled as the Euler beam and the sidewall is regarded as the sub-sectional spring with lumped mass. The dynamics equation is dispersed using finite difference method, and three-parameters model is derived based on the geometrical and structural parameters. The structural parameters of tire are identified by the genetic algorithm based on the experimental modal parameter of heavy duty tire, and the higher order modal frequency is predicted using the analytic method. The analytical transfer functions between carcass and carcass, and carcass and sidewall are derived. Experimental and theoretical results show that the rigid-elastic coupling model can be used accurately to predict the transfer function and vibration feature of heavy duty tire within the frequency band of 300 Hz, compared with the method in which only the coupling of carcass and rim is considered, and is limited to 180 Hz. Key

Numerical Simulation and Analysis of Flow Field during Dynamic Launching of Electromagnetic Rail Launcher Based onOverlapping Multi-block Structured Mesh

DU Pei-pei， LU Jun-yong， FENG Jun-hong， LI Xiang-ping

2018, 39(2):  234-244.  doi:10.3969/j.issn.1000-1093.2018.02.004

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The airflow distribution and law of muzzle flow field during the dynamic launching of electromagnetic rail launcher are studied. A two-dimensional transient model of projectile under high Mach number is established based on overlapping multi-block structured mesh, DFBI and Java program. The unsteady numerical method and the reliability of data interaction are validated by taking double ellipsoid model as the object of study. The flow fields in the dynamic launching processes of four cases are simulated. The numerical results show that the complex flow fields due to the interaction of projectile nose shock wave, spherical shock wave with moving center and coronal shock wave are generated in the dynamic launching process of electromagnetic rail launcher.The shock wave is out of the muzzle from the front projectile to the tail of projectile, and the pressure distribution at the midpoint of projectile nose presents symmetry. The resistance coefficient is related to the pressure distribution which presents a weak symmetry after the shock wave being out of the muzzle, which reachs a peak at the tail of projectile. When the projectile moves in the air, and the second peak pressure is greater than the first because of the superposition of the shock wave and its reflection. The farther the distance is, the smaller the reflection period is, the slower the pressure decays. Key

Mesoscopic Numerical Simulation on the Formation of Tunsgsten-copper Shaped Charge Jet

WANG Fang, JIANG Jian-wei, MEN Jian-bing

2018, 39(2):  245-253.  doi:10.3969/j.issn.1000-1093.2018.02.005

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A generation program of W-Cu meso-discrete model was developed to investigate the mesoscopic mechanism of tungsten-copper (W-Cu) shaped charge jet formation and the effect of microstructure of W-Cu composites on the jet characteristics. The discrete models of W-Cu liner with different ratios of two phases and various diameters of tungsten particles were successfully established. The multi-scale finite element numerical simulations are carried out on the particle-matrix materials and the referenced equivalent homogeneous material by using AUTODYN-2D Euler solver. The results show that the average velocity of Cu phase is much higher than that of W, leading to a phase segregation and composition gradient in W-Cu jet during its forming process. The content of Cu is higher in the jet tip compared with the liner material while the W particles mainly concentrate in the slug. For the W particles with same size, the relative change amount of W content in the jet increases with the decrease in W content in the original materials. For the same component content, the W content in jet decreases with the growth in the diameters of tungsten particles. The composition gradient is more sensitive to the size of W particle in jet with higher W content. Key

Research on the Explosion Mass Loss Rate of Pre-formed Fragment Warhead Shell with Symmetric Groove

ZHANG Gao-feng, LI Xiang-dong, ZHOU Lan-wei, MA Li-ying

2018, 39(2):  254-260.  doi:10.3969/j.issn.1000-1093.2018.02.006

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The fracture path of shell caused by the axial groove and circumferential groove is analyzed to study the explosion mass loss rate of pre-formed fragment warhead shell with symmetric groove. The source of explosive mass loss is determined. The explosion mass loss rate of typical warhead shell is calculated in theory. Two kinds of simulated warhead were designed, and the static explosion test was carried out under water. The test results and theoretical analysis show that, in the process of explosion, the axial groove on the shell causes two symmetrical fracture traces from the groove root, the circumferential groove on the shell causes only one fracture trace from the groove root. The explosion mass loss rate of shell is caused by axial groove. The greater the groove depth is, the smaller the mass loss rate of shell explosion is. The difference between theoretically calculated and experimental mass loss rates is less than 8%. Key

Investigation of Hyper Shaped Charge Jet Formation Theory

XU Wen-long, WANG Cheng, XU Bin

2018, 39(2):  261-268.  doi:10.3969/j.issn.1000-1093.2018.02.007

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A theoretical calculation method for the formation of hyper shaped charge jet is proposed. The theoretical relations among material density and thickness of additional body, and cone angle, material density and thickness of truncated liner and the velocity and effective mass of hyper-accumulation shaped charge jet are given. The simulated results of the formation process of hyper shaped charge jet based on AUTODYN software are basically the same as the theoretically calculated results. The numerical results of hyper shaped charge jet penetration are in good agreement with the experimental results. The results show that, within a certain range, the velocity of hyper shaped charge jet decreases and its mass increases with the increase in cone angle; the velocity, effective mass and penetration ability of hyper shaped charge jets are much larger than those of classical shaped charge jets. Key

Analysis of the Effect of Projectile Conical Motion on the Stability of Semi-strapdown Stabilized Platform

LI Jie, ZHENG Tao, FENG Kai-qiang, DU Si-yuan, ZHANG Xi, YANG Yan-yu

2018, 39(2):  269-275.  doi:10.3969/j.issn.1000-1093.2018.02.008

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In order to solve the problem of that the swing angular velocity of the stabilized semi-strapdown platform is increased due to the coning motion of projectile, the variation law of friction torque of bearing driven by the semi-strapdown stabilized platform is analyzed. Based on the novel calculation model of SKF, the friction torque of bearing under the coning motion of projectile is simulated by the Runge-Kutta method. The theoretical value of swing angular rate of semi-stapdown stabilized platform under conical motion is obtained based on the working principle of the stabilized platform. The ground semi-physical test is conducted to verify the theoretically analyzed results. The experimental results are compared with the theoretically simulated results. It shows that there both exist high and low frequency angular rates whose frequency and amplitude are consistent, and the angular rate of low frequency is constant. The frequency of high frequency angular rate coincides with that of projectile roll angular rate. It indicates that the increase in the swing angular velocity of semi-strapdown stabilized platform is due to the changes of its pitch angle and the pressure on bearing resulting from the coning motion of projectile, which causes the friction torque of bearing to change with the roll angular rate of projectile at same frequency, and finally superimposes the angular rate of high frequency on the stabilized platform.Key

Numerical Simulation on Concentration Distribution Characteristics of Dust Raised during Tank Moving

CHEN Hui-min, FENG Xing-tai, WANG Feng-jie, LIU Wei-bo

2018, 39(2):  276-282.  doi:10.3969/j.issn.1000-1093.2018.02.009

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The distribution of dust concentration in battlefield plays an important role in the study of anti-dust interference of laser fuze. Based on the computational fluid dynamics method, the RNG k-ε model and the discrete phase model are used to simulate the distribution rule of dust raised during tank moving. The dust distribution graphics and the changes of mean concentration with time on different cross sections in the computational domain are analyzed, and the influence rule of moving speeds of tank on the concentration distribution of raised dust is obtained. The results show that the dust concentration near tank tail changes more rapidly, while the dynamic range of dust concentration far away from the rear area of tank is larger. The influence of gravity on dust diffusion can be neglected, and the area of dust distribution is larger when the tank moves faster. Besides, the dust concentration decays exponentially in vertical direction. Key

Location Method of Equivalent Attenuation Magnetic Moment of Magnetic Target in Geomagnetic Field

JIA Wen-dou, LIN Chun-sheng, SUN Yu-hui, ZHAI Guo-jun

2018, 39(2):  283-289.  doi:10.3969/j.issn.1000-1093.2018.02.010

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A location method based on equivalent attenuation magnetic moment is proposed to obtain the position parameter of magnetic target in geomagnetic field. A spatial model of regular hexahedron is established to measure the magnetic field for magnetic source positioning. The equivalent attenuation moments of the geometric central point and the side central point of regular hexahedron are calculated. The positioning formula based on equivalent attenuation magnetic moment for magnetic dipole target is deduced. The influences of some factors, such as geomagnetic field, magnetic gradient measurement noise, regular hexahedral baseline, measurement accuracy and so on, on the location inversion parameter of magnetic target are analyzed. The calculated results show that the proposed method can effectively overcome the interference of the geomagnetic field and achieve a reliable positioning result of magnetic target. The proposed method can significantly reduce the size of the original computation model by 64.7% with higher positioning accuracy. Key

Research on Burning Rate Law of High Density Compacted Black Powder in Low Pressure Environment

CHENG Long, LIU Pan, YANG Hong-tao, ZHU Xu-qiang, YANG Yue, CHENG Yi, SONG Dong-ming

2018, 39(2):  290-295.  doi:10.3969/j.issn.1000-1093.2018.02.011

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Black powder is a classic ignition powder, but its combustion performance in low pressure (high altitude) environment has been rarely studied. In order to research the combustion performance of black powder at low pressure, the burning rates of black powders with differential densities at differential temperatures and differential pressures are measured using an optic-electric target method. The research results show that the burning rate of black powder decreases linearly and rapidly with the drop of pressure, and the black powder can not be ignited or burning constantly at the pressure of ≤20 kPa. The burning rate of black powder increases slowly as the decrease of density or the rise of temperature, and the effect of density or temperature on the burning rate of black powder can be gradually increased or reduced with the decrease in pressure. In general, compared with density and temperature, the pressure has more important effect on the burning rate of black powder. The change of the burning rate of black powder with pressure and temperature is established based on the mathematical simulation. Key

Research on the Electrical Properties of Propellant Combustion Products Containing Potassium Salt

MAO Bao-quan， LI Cheng， BAI Xiang-hua， LAN Tu

2018, 39(2):  296-304.  doi:10.3969/j.issn.1000-1093.2018.02.012

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In order to improve the electrical properties of propellant combustion products, the alkali metal compound K₂CO₃ with low ionization potential is added to improve the degree of ionization based on the theory of thermal ionization of gases. Through the analysis of physical and chemical processes of combustion reaction of propellant, a thermoelectric model of propellant gas is established by means of the interior ballistic theory and plasma theory. The thermodynamic processes of combustion pressure and combustion temperature are simulated, and the feasibility of the proposed model is verified by comparing the calculated results with the experimental data. Saha equation and staggered method are used to analyze the effects of propellant force, combustion chamber volume and potassium content on the electron density and conductivity of combustion products. The emission spectrum intensities of combustion products without or with potassium salt are measured using spectrometry. The results show that K₂CO₃ can make the propellant gas have higher conductivity, the increase in propellant force and chamber volume can improve the conductivity of combustion gas. Key

Finite Time Cooperative Guidance Law for Multiple Missiles with Line-of-sight Angle Constraint

LYU Teng， LYU Yue-yong， LI Chuan-jiang， GUO Yan-ning

2018, 39(2):  305-314.  doi:10.3969/j.issn.1000-1093.2018.02.013

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To solve the problem of multiple missiles attacking a maneuvering target simultaneously from desired directions in plane, a novel cooperative guidance law with line-of-sight angle constraint is proposed. A multiple missiles cooperative guidance model with line-of-sight angle constraint is constructed based on in-plane missiles-target relative motion equations. A distributed finite time cooperative guidance law in the line-of-sight direction is designed based on multi-agent system cooperative control theory and integral sliding mode control theory, which can guarantee the consensus of all missiles' impact times in finite time. In vertical direction of line-of-sight, a nonlinear disturbance observer is adopted to estimate the target's acceleration in finite time, and a guidance law with line-of-sight angle constraint is designed based on finite time sliding mode control theory. The guidance law can guarantee the missile impact the maneuvering target and the missile's line-of-sight angle converge to its desired value in finite time. The cooperative guidance law is demonstrated through simulation results, which makes multiple missiles impact the maneuvering target simultaneously from desired directions. Key

An Improved SINS/GNSS/CNS Federal Filter Based on Dual Quaternions

MIN Yan-ling, XIONG Zhi, XING Li, LIU Jian-ye, YIN De-quan

2018, 39(2):  315-324.  doi:10.3969/j.issn.1000-1093.2018.02.014

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In traditional SINS/GNSS/CNS federal filter, the master filter and the local filters have the same state variables. However, the attitudes information output by CNS is observable for some state components in state vector. In common SINS/CNS integrated mode, the output information of CNS needs to be converted to navigation coordinate frame, which may decrease the accuracy of integrated navigation system. For the problems above, an improved SINS/GNSS/CNS federal filter based on dual quaternions is proposed. The dimension of local filter is decreased by the observability analysis of state vector, which assures the navigation accuracy and improves the real-time performance at the same time. The improved SINS/CNS integrated mode based on dual quaternions can utilize the attitudes information of CNS to integrate directly and avoid using those unobservable state components to correct SINS. Thus, the effective use of high precision CNS information is realized. The simulated results show that the proposed method has the same navigation accuracy as centralized Kalman filter, and can obtain better navigation performance when GNSS signal is lost.Key

Development of Gain-clamped 850nm Superluminescent Diode

ZHU Zi-xiang， ZHANG Jing， SUN Chun-ming， QIAO Zhong-liang， GAO Xin， BO Bao-xue， LI Hui， WANG Xian-tao， WEI Zhi-peng， MA Xiao-hui

2018, 39(2):  325-330.  doi:10.3969/j.issn.1000-1093.2018.02.015

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A three-quantum-well structure with nonuniform well width at active region of epitaxial wafer and a large asymmetric optical cavity structure at waveguide region are designed to improve the spectrum width and output power of superluminescent diode. A new device structure is proposed by using gain-clamped theory, and a multi-wavelength gain clamping system is designed. The nanoimprint technology is used to prepare a nanorod for multi-wavelength surface distributed feedback clamping system on device ridge mesa. Ridge length of pumping region in the fabricated device is 350 μm, the length of absorption region is 250 μm, and the messa is 5 μm in width and 1 μm in height. When the working current is 160 mA, the continuous output power at room temperature is 14.63 mW, the central wavelength is 848.7 nm, and the half band width is 22 nm. The new structure design can be used to gain the non-central wavelength of device, suppress the F-P oscillation of central wavelength , expand the spectral width, and realize the gain clamping of central wavelength. Key

Non-homogeneous Training Sample Detection Method Based on Sparse Recovery with Prior Information

LI Zhi-hui, ZHANG Yong-shun, LIU Han-wei, WANG Qiang, LIU Yang

2018, 39(2):  331-337.  doi:10.3969/j.issn.1000-1093.2018.02.016

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For the degradation of target detection performance in space-time adaptive processing (STAP) due to non-homogeneous training samples contaminated by target-like signals, a non-homogeneous training sample detection method based on prior information and sparse recovery is proposed. The sparse representation coefficient of cell under test (CUT) is recovered using focal underdetermined system solver (FOCUSS). A “sparse filter” is constructed based on radar system parameters.The target and “pseudo point” signals are filtered out by “sparse filter”, and the clutter covariance matrix is estimated. The generalized inner product (GIP) method is integrated to eliminate the contaminated training samples. Simulation analyses show that the proposed method can effectively eliminate the contaminated training samples and improve the target detection performance of STAP in non-homogeneous environment. Key

Simulation Research on Underwater Non-free Sound Field Reconstruction Based on Normal Mode and Wave Superposition

ZHOU Si-tong，HE Lin，SHUAI Chang-geng，YANG Jia-xuan

2018, 39(2):  338-344.  doi:10.3969/j.issn.1000-1093.2018.02.017

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Considering that amounts of measuring points need to be laid for reconstructing the sound field of large structure, a calculation method of using a horizontal linear array to reconstruct the sound field is proposed. The distribution of circular and straight-line virtual sources is determined from the vibrating velocity of structural surface, and the sound field is reconstructed by using wave superposition method. On this basis, the interpolation iteration method is adopted to improve the reconstruction accuracy under the condition of less measuring points. The influence of the uneven distribution of energy in shallow water channel on reconstruction is corrected according to the principle of normal mode. The reconstruction performance of sound field is analyzed from the aspects of virtual source shape, transmitting or receiving distance, signal frequency and water depth. The theoretical and simulated results show that the proposed method is simple and effective for reconstruction of sound field in the non-free field environment. The distribution of complex virtual source is more adaptable to complex structures. Key

Application of Differential Recursion Method in Depth Conversion of Ship Static Electric Field

SUN Jia-qing， CHEN Cong， WEI Yu-qian， LI Ding-guo

2018, 39(2):  345-355.  doi:10.3969/j.issn.1000-1093.2018.02.018

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For the divergence and curl of electric field generated by the ship, which are zero in the converted area, the first-order vertical partial derivative of node on the measuring plane can be calculated by using the horizontal partial derivative, and the recursion relation can be formed based on the Newton-Leibniz formula. A differential conversion method is given to convert the electric field distribution on the measuring plane to that on the target plane. The feasibility of the method is proved by using the horizontal electric dipole (HED) as the basic simulating unit of ship static electric field through simulation and experiment. Further analysis shows that the converting precision and efficiency of the method can be improved by changing recursive step, node interval and the distance between the sensors and the sea bed. Key

Research on the Friction and Wear Properties of Diesel Engine Cylinder Liner with Different Surface Textures

RAO Xiang, SHENG Chen-xing, GUO Zhi-wei

2018, 39(2):  356-363.  doi:10.3969/j.issn.1000-1093.2018.02.019

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The different surface textures of cylinder liner has a significant effect on the performance of diesel cylinder liner-piston ring friction pairs, thus affecting the service life, reliability and economy of diesel engine. In order to improve the tribological properties of cylinder liner-piston ring friction pairs，the cylinder liners with different surface textures are test to obtain the friction characteristic data under the conditions of same speed and different loads. The tset results show that the friction characteristic parameters of cylinder liner are obviously different. The tribological properties of cylinder liners with surface textures under different running conditions are compared and analyzed. It is concluded that the cylinder liner with annular square groove is more suitable to run under low load, while anyway tank is more fit to run under medium and high loads. Key

Prediction Method for Roundness Error of Machined Deep-hole Based on Vibration Behaviors of Cutting Tools

LI Chao, KONG Ling-fei, LIANG Yan-ming, JIANG He-ling, YAN Dong

2018, 39(2):  364-372.  doi:10.3969/j.issn.1000-1093.2018.02.020

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On the basis of feature of machined deep hole, an intelligent recognition method is proposed to predict the roundness error of machined hole by using the time-frequency domain information of machining tool cutting vibration. In order to establish the relationship of tool cutting vibration and roundness error, the partitioning problem of the fuzzy input-space of vibration mode is converted into the initial value of input space by introducing the modified fuzzy clustering algorithm into support vector machine, so that the higher accuracy and generalization ability of the proposed method are guaranteed simultaneously. On this basis, a prediction model for roundness error of machined deep-hole is built. A series of experiments were conducted with different cutting parameters and electric currents acting on vibration suppression instrument. The experimental results show that the proposed method is effective and feasible.Key

Analysis and Verification of Vibration Response of Fiber-reinforced Cantilever Composite Thin Plate in Thermal Vibration Environment

LI Hui, WU Huai-shuai, ZHANG Ti-nan, WEN Bang-chun

2018, 39(2):  373-382.  doi:10.3969/j.issn.1000-1093.2018.02.021

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The vibration response of fiber-reinforced cantilever composite thin plate in thermal vibration environment is analyzed based on theory and practice. With consideration of the influence of base excitation load, a theoretical model of cantilever composite thin plate is established, and the vibration responses are obtained by the two-dimensional beam function method. The theoretical model of composite thin plate is modified based on the measured natural frequencies, damping ratio and modal shapes at room temperature, so that the material parameters, such as elastic modulus and loss factor, can be accurately obtained, and the vibration response can be calculated by the modified theoretical model. TC500 fiber/ epoxy composite plate is taken as an object of study, and its vibration responses are measured using the established vibration test system in thermal vibration environment. The measured results show that the error between theoretically calculated result and experimental result is in the range from 1.4% to 12.5%, thus verifying the effectiveness of the proposed theoretical method. Key

Analysis of Probability of Exterior Ballistic Projectiles from Rapid-fire Weapon Simultaneously Passing through a Screen

CHEN Ding， NI Jin-ping， LI Xiao-juan

2018, 39(2):  383-390.  doi:10.3969/j.issn.1000-1093.2018.02.022

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In the firing accuracy and dispersion test of rapid-fire weapon, several projectiles fired from a barrel may pass through a light-screen simultaneously. On this condition, some photoelectric target measurement systems cannot measure the exterior ballistic parameters of these projectiles. A qualitative analysis of this phenomenon should be undertaken to obtain the measured values for choosing a reasonable photoelectric target measurement system. The reduced mathematics description of the phenomenon is presented. The two mathematical models for the probability passing through the screen are established, respectively, based on certain and uncertain velocities of the flying projectiles. The change rule of the passing probability with projectiles’ flight distance is deduced according to the optimization mathematical model, and the three important parameters, such as critical distance involved in the passing probability, maximum probability and passing probability at direct fire distance. Experiments show that the reasonably chosen photoelectric target measurement system can avoid the measurement data being influenced by the projectiles passing through a screen simultaneously. Key

Missile Condition Assessment Based on Multi-state Bayesian Network

XU Ting-xue, LI Zhi-qiang, GU Jun-yuan, CONG Lin-hu, AN Jin, ZHAO Jian-zhong

2018, 39(2):  391-398.  doi:10.3969/j.issn.1000-1093.2018.02.023

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A condition assessment model of missile based on Bayesian network (BN) with conditional probability table (CPT) which is determined by using DS evidence theory and analytic hierarchy process (AHP) is established for the extensive way and inadequate information resources ultilization of traditional state classification method. Missile state is divided into five grades, i.e., perfect, better, usable, pseudo-fault and fault, based on the analysis of characteristic parameters. Normalization processing is carried out on the test parameters of different units and threshold values, and the modified ridge shape functions are used to determine the degree of membership of all the states. A BN-based condition assessment model of a missile is established. In the view of uncertain logical relationship between nodes and lacking of data, a method is proposed to determine CPT of multi-state Bayesian network on the basis of DS evidence theory and AHP. The result shows that uncertainty is decreased to about five percent by utilizing DS/AHP method to determine CPT. The reasonability and credibility of BN model are verified through horizontal and vertical comparison.Key

An Optimization Solution to Armament Parallel Test Task Scheduling

WANG Zheng-yuan, LIU Wei-dong, JING Hui-li, QU Na

2018, 39(2):  399-404.  doi:10.3969/j.issn.1000-1093.2018.02.024

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Armament parallel test task scheduling is a complicated combinatorial optimization problem which is difficult to solve efficiently. An optimization model is proposed for a parallel task scheduling problem of armament test. Parallel task scheduling problem of armament is decomposed into the armament test task allocation on assembly lines and the task scheduling problem of armament test on single assembly line on the basis of the problem’s characteristics. It has reduced the difficulty in solving the original problem. The solutions to these sub-problems are proposed, respectively. A lower bound to the task scheduling problem of armament test on single assembly line is constructed, which results in great decrease in computation of two sub-problems. Experimental results show that the solution to parallel task scheduling problem of armament test proposed here is valid.Key

Tilt Error Analysis of Digital Zenith Instrument Positioning at Large Dip Angle

ZHANG Xi-hui， ZHOU Zhao-fa， LIU Xian-yi， ZHU Wen-yong， YANG Shang

2018, 39(2):  405-410.  doi:10.3969/j.issn.1000-1093.2018.02.025

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The self-correction method of inclination compensation value is studied for the axis error between the vertical axis and the rotating shaft at large dip angle, and the accuracy of the inclination compensation value is improved. Based on the principle of inclination compensation of digital zenith instrument, the accuracy of inclination compensation value is proposed to be mainly related to the reading error of inclinometer. A correction model of rotation axis is established based on the theoretical analysis, and the inclination component of rotating shaft is deduced. It is concluded that the linear drift and zero error of inclinometer can be eliminated by correcting the average value of tilt errors of symmetrical observation position. The method of eliminating the tilt error is verified by experiment. The results show that the positioning accuracy of digital zenith instrument is improved from 0.5″ to 0.3″ after the correction of tilt error.Key

Research Notes

Optimal Design of Automatic Charging Device for Warhead Based on Rigid-flexible Coupling

YIN Meng， XU Zhi-gang， HE Yun， LIU Zhe

2018, 39(2):  411-416.  doi:10.3969/j.issn.1000-1093.2018.02.026

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The traditional charging process of warhead is finished by hand, and the charging efficiency is low and the charging quality is not guaranteed. An automatic charging device for warhead is proposed. The structure of charging device is designed, and for the jitter problem of automatic charging device, a dynamics model is established based on rigid-flexible coupling. Through the comparison of acceleration control algorithm and S curve algorithm, it is found that the jitter of charging device is the weakest when using the S curve algorithm. The S curve algorithm is optimized to five segments and is implemented on the controller by interpolation fitting. In physical testing, the S curve algorithm can be used to avoid jitter obviously. The results show that the optimized algorithm has better control performance. The S curve algorithm is optimized and applied to reduce the jitter of the device. Key