Table of Content

29 February 2016, Volume 37 Issue 2

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Paper

Design and Test of a Hybrid Sensor for Temperature and Heat Flux Measurement without Water-cooling

YANG Qing-tao, WANG Hui, ZHU Xin-xin, ZHOU Ping

2016, 37(2):  193-202.  doi:10.3969/j.issn.1000-1093.2016.02.001

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A method for rapid measurement of surface temperature and heat flux in the absence of water-cooling during long-time flight is studied for the parameter measurement demands in hypersonic flight test. Based on the analysis of environment characteristics and measurement demands, a novel plug hybrid sensor with self-fastening structure is designed, which could be used to achieve the surface temperature and heat flux data according to the measured result of temperature on the side of a cylinder. A polynomial approximation method based on the least square method is presented. FEA simulation results show that better anti-distortion and anti-noise performances could be achieved using the proposed method. The sensor is calibrated in an arc lamp heat flux sensor calibration system for heat flux verification. 98% response time of stainless steel sensor is about 0.7s. In addition, the measured results of heat flux are affected evidently by the adiabatic structure. The comparative test results of surface temperature show that the data achieved by the sensor could reflect the effect of surface temperature on heat flux.

Study of Integrated Control of All-wheel-steering Three-axil Vehicle

LIU Wei-ping, YUAN Lei, LIU Xi-xia

2016, 37(2):  203-210.  doi:10.3969/j.issn.1000-1093.2016.02.002

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In order to improve the handling stability of three-axil vehicle at high speed, a control method, that integrates all-wheel steering system and direct yaw moment control system, is proposed, which includes the upper coordinated controller and the lower controller. Based on the 18-DOF vehicle model, the load distribution model and the Dugoff nonlinear tire model, the steering on low friction road and the obstacle avoidance steering are simulated. The simulated results show that the integrated control method can improve the handling stability and active safety of vehicle at high speed.

Direct Yaw Moment Control in Dual-steering for In-wheel Motor Drive Vehicle

YANG Gui-bing, MA Xiao-jun, LIAO Zi-li, LIU Chun-guang

2016, 37(2):  211-218.  doi:10.3969/j.issn.1000-1093.2016.02.003

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A dual-steering control strategy based on direct yaw moment control for 8 in-wheel motor drive wheel vehicle is designed. A double-track vehicle kinematics model with 2-DOF is established. A vehicle reference model which includes the skid-steering condition is studied. And the skid-steering ratio is adjusted fuzzily based on the vehicle speed and the road adhesion condition. In order to balance the contradiction between the control of yaw rate and the limitation of side-slip angle, the yaw rate is set to be a direct control variable, and the side-slip angle is set to be a constraint variable in this model. The yaw torque is adjusted by sliding mode variable structure control algorithm. The driving torque is optimally distributed through the strategy of combining the predistribution and driving skid-resistance control.The proposed control algorithm for dual-steering established is proved and analyzed by a real-time simulation in hardware-in-loop. The simulated results indicate that the dual-steering control strategy can effectively improve the steering flexibility and operation stability of the in-wheel motor drive vehicle, which is of great significance for improving the battlefield viability of wheeled armored vehicles.

Research on Initial Alignment of Moving Base with 5th-degree Dimensionality Reduction SR-CKF

HUANG Xiang-yuan, TANG Xia-qing, WU Meng, WU Wei-sheng

2016, 37(2):  219-225.  doi:10.3969/j.issn.1000-1093.2016.02.004

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In order to achieve higher alignment precision, stronger numerical stability and lower computational cost for nonlinear alignment of strapdown inertial navigation system (SINS) on moving base, a scheme of 5th-degree dimensionality reduction SR-CKF nonlinear alignment is proposed，which combines 5th-degree cubature Kalman filter (CKF), dimensionality reduction algorithm, multiple discretization, and square root(SR) filter. A nonlinear-linear separation system model is established, and the dimensionality reduction algorithm is introduced to reduce the calculated amount. A multiple discretization and time update filter framework is designed to improve the approximation accuracy. The 5th-degree dimensionality reduction SR-CKF is deduced to improve the numerical stability. The features of the conventional 3rd-degree SR-CKF, 5th-degree CKF and the proposed algorithm are compared. The experimental results show that the proposed method has a high alignment precision, strong numerical stability and little calculated amount, which meets the application requirements.

Experimental Research on Dynamic Concentration Distribution of FAE Solid Fuel

GUO Ming-ru, LOU Wen-zhong, JIN Xin, DAI Xi-ming

2016, 37(2):  226-231.  doi:10.3969/j.issn.1000-1093.2016.02.005

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The appropriate concentration of fuel cloud is a precondition of the detonation reaction. Because of the complex mechanism of the dispersing process and the lack of the testing devices, the special experimental research on the dynamic concentration distribution of fuel is still very lack. An array experimental system based on the concentration measurement microsystem CMM-1 is established to detect the concentration of the fuel cloud generated by a scaled-down dispersing device; the temporal and spatial variation curves of the fuel concentration are obtained, and the change law of the concentration peak is established. The experimental results show that the dynamic concentration distribution of fuel can be obtained using the experiment system and the proposed method.

Research on Acquisition Probability of a Novel Hedgehopping Terminal Sensitive Projectile

ZHAO Bo-bo， LIU Rong-zhong， GUO Rui， CHEN Liang， LIU Lei， YANG Yong-liang

2016, 37(2):  232-238.  doi:10.3969/j.issn.1000-1093.2016.02.006

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The operational effectiveness of a novel scanning mechanism of the hedgehopping terminal sensitive projectile is evaluated, and the acquisition performance of the terminal sensitive projectile on terminal trajectory is studied. The coordinate transformation is used to obtain the scanning linear equation of hedgehopping terminal sensitive projectile, and the coupled solution of its 6-DOF trajectory equation set is solved so that the steady scanning area could be determined. The acquisition probability expression is derived by proving the scanning dependent area theory. The results indicate that the space scanning track of the hedgehopping terminal sensitive projectile is helical, the space scanning area is cylindrical, and the scanning area on the plane is semi-elliptical. The acquisition probability can be significantly improved by decreasing the firing angle, estimating the target movement exactly, and increasing the initial velocity of projectile. The acquisition probability calculated using the analytical expression agrees with the results predicted based on the Monte Carlo shooting method, which verifies the correctness of the analytical expression.

Relevant Concepts of Cluster Submunition Fuze and“Three-self ” Combined Design Method

QIN Dong-ze

2016, 37(2):  239-244.  doi:10.3969/j.issn.1000-1093.2016.02.007

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In order to help to solve the unexploded issue of cluster munitions, the concepts of self-destruction, self-neutralisation, self-deactivation and sterilization are described. The development and connotation of the concepts and their technical implementation are analyzed. For the “three-self” fuze of typical cluster submunition, the design method of “three-self” combined fuze is abstractly described in the form of block diagram. The safety and reliability of the “three-self” fuze of typical cluster submunition are analyzed with the experimental data and theoretically calculated results. The analyzed results show that sterilization is quite different from self-neutralisation and self-deactivation in connotation and implementation technology. The“three-self” combined fuze can be used to increase the comprehensive effect of fuzes. A self-destruction and self-neutralisation device should be integrated with a detonation interrupter if a combination design of self-destruction and self-neutralisation is used, and the self-destruction device should have a redundant safety control. In the combination design of self-destruction and self-deactivation, the redundant safety control should be used to enhance the security of the electronic self-destruction devices.

The Influence of Combustion Product Properties on Gas-ejection Interior Ballistic and Load Characteristics

LI Ren-feng， LE Gui-gao， MA Da-wei

2016, 37(2):  245-252.  doi:10.3969/j.issn.1000-1093.2016.02.008

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Realizable k-ε turbulence model, dynamic mesh update method and finite-rate/dissipation model are used to establish an initial cavity secondary combustion flow model with missile movement for research on the influence of combustion product properties on gas-ejection secondary combustion, interior ballistic and load characteristics. The effectiveness of gas ejection model is proven by comparing the calculated data with the experimental data. The influences of combustion product pressure in gas generator inlet and component concentration on gas-ejection interior ballistic and load characteristics are analyzed. The variation ranges of inlet pressure and concentration ratio are obtained. The numerical results show that, with the increase in inlet pressure，the times of O₂ exhaustion and the time out of tube decrease, and the velocity out of tube and the acceleration peak value increase. With the increase in the concentration ratio of CO and H₂, the time of O₂ exhaustion increases, the time out of tube is extended, and the velocity out of tube and the acceleration peak value decrease.

Study of Wounding Assessment Methods for Flexible Anti-riot Kinetic-energy Projectiles

PU Li-sen, LI Xu-qiang, XU Peng, SHU Nan

2016, 37(2):  253-259.  doi:10.3969/j.issn.1000-1093.2016.02.009

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Flexible anti-riot kinetic energy projectile is deformed when it impacts a target, which make it difficult to evaluate the specific kinetic energy of projectile. Three methods, such as traditional wounding assessment, animal experiment and wounding assessment based on impact pressure, are used to evaluate the wounding efficiency of the flexible anti-riot kinetic projectile. The experimental results show that the traditional lethality assessment method is not appropriate for the flexible anti-riot kinetic projectile, and the lethality assessment method based on impact pressure could be adopted to evaluate the wounding efficiency of the flexible anti-riot kinetic projectile while the one-quarter principle is used.

Surface Modification of Cellulose Nano-fiber and Its Effect on Mechanical Properties of Nitrocellulose Film

WANG Wen-jun, CUI Xiao-yue, ZHU Hai-dong, SHAO Zi-qiang, ZUO Ying-ying

2016, 37(2):  260-264.  doi:10.3969/j.issn.1000-1093.2016.02.010

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Cellulose nano-fibers(CNFs) are prepared by TEMPO-mediated oxidation combined with homogenizing mechanical treatment. The carboxyl groups on the surface of CNFs are removed by an alkalization process. Then CNFs are chemically modified by a mixture of nitric acid and dichloromethane to obtain nitrified CNF(NCNF). NCNFs could readily suspend and well disperse in acetone. The structure and properties of NCNFs are examined using Fourier transform infrared spectroscopy (FTIR)，elemental analysis (EA)，and transmission electron microscopy (TEM). The nano-nitrocellulose composite films with NCNF as reinforcment are prepared by a casting/evaporation technique. The tensile properties of the nanocomposite films are tested. The results show that the tensile strength，Young’s modulus，and elongation at break of the nanocomposite films increase simultaneously in comparison with that of neat NC. The influence of cellulose nanowhiskers(CNWs) and CNFs on the tensile properties of nanocomposite films is studied. As reinforcement, CNFs demonstrate higher efficiency compared to CNWs because of their larger aspect ratio.

A One-position Comprehensive Calibration Method for Long-endurance Strapdown Inertial Navigation Systems

FENG Lu，DENG Zhi-hong，WANG Bo，WANG Shun-ting

2016, 37(2):  265-271.  doi:10.3969/j.issn.1000-1093.2016.02.011

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A one-position comprehensive calibration method based on inertial frame is proposed to suppress the divergence of errors of a strapdown system. The auxiliary navigation information is provided by GPS and celestial navigation system. The coefficients in the error model of traditional comprehensive calibration methods are basically determined by outputs of the INS, thus the computational errors of INS are introduced into the error model. These modelling errors are amended according to the auxiliary navigation information in the proposed method relaxing the constraint to speed and trajectory of the vehicle. Kalman filter is utilized to estimate the gyro constant drifts. The effectiveness of the method is demonstrated by simulation.

Research on Gyroscope Array Based on Kalman Filter

LIU Ming-yong, ZHU Li, DONG Hai-xia

2016, 37(2):  272-278.  doi:10.3969/j.issn.1000-1093.2016.02.012

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The same type of measurement axes of gyroscope are parallel to each other. The information processing algorithms to improve the accuracy of inertial measurement via gyroscope array are researched. Two different drift models of single MEMS gyroscope are established, and the random drift coefficients are identified via Allan variance. Then the identified random drift coefficients are used for Kalman filter, and the muti-gyroscopes information is fused to acquire a highly precise output of gyroscope array through Kalman filter. The result proves the stability of Kalman filter. Finally, the advantages and disadvantages of different modeling methods are compared by experiment. The experimental results show that the accuracy of MEMS gyroscope can be improved effectively by the information fusion method based on Kalman filter.

Projectile Roll Angle Measurement Method of a Combination of Strapdown Laser Detector and GPS Measurement forSemi-active Laser Terminal Correction

LI Xing-long, YAO Wen-jin, ZHU Li-kun, WANG Xiao-ming, YU Ji-yan

2016, 37(2):  279-286.  doi:10.3969/j.issn.1000-1093.2016.02.013

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A method of which uses the measured information from onboard laser detectors and GPS to resolve the roll angle of semi-active laser terminal correction projectile is proposed. A formula to calculate the roll angle is deduced by comparing the real target imaging point on imaging planeof laser detector with the calculated target imaging point on non-roll imaging plane.The effects of measured errors of projectile position, projectile velocity and laser detector on the resolving accuracy of roll angle at different quadrant elevation angles are analyzed through the Monte-Carlo simulation. The simulated results show that the maximum error of roll angle is resolved to be less than 4° by the proposed method; the measured error of laser detector has the greatest effect on the resolving accuracy of roll angle among the 3 error sources.The proposed resolving method meets the accuracy and real-time requirements, and is suitable for solving the roll angle of semi-active laser terminal correction projectile with low rolling.

2D Combustion Model and Numerical Simulation of Mg-Teflon Pyrolant Based on Flow-chemistry Coupling

LIN Chang-jin， WANG Hao， ZHU Chen-guang

2016, 37(2):  287-292.  doi:10.3969/j.issn.1000-1093.2016.02.014

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A two-dimensional computational fluid dynamics(CFD) model for flow-chemistry coupling is established to analyze the influence of turbulence on the combustion of Mg-teflon (MT) pyrolant. The steady combustion of MT pyrolants with different mixing ratios was simulated, and the combustion temperature and composition distribution characteristics were obtained. The calculated results are compared with the values in Refs.\[10,16,18\]. The compared results show that the rising step of temperature in the combustion field is about 20mm, which agrees well with the experimental data in Ref.\[10\]. The distance of temperature rising step is corresponding to the reaction region of C₂F₄+M2CF₂+M. The highest temperature of MT pyrolant with equivalent mixing ratio (33/67) is consistent with the thermodynamic calculated result. With the increase in mixing ratio, the incomplete reaction happens. Mg is mainly consumed through its oxidizing reaction with CF₂. The reaction of Mg with F cannot be neglected. The percentage of combustion product MgF reduces with the increase in mixing ratio.

Effect of Narrowband Interference Suppression on Pseudorandom Code Zero Value

LIU Yong-qing， JIANG Shuo， YU Dong， SHAO Xiao-tian

2016, 37(2):  293-298.  doi:10.3969/j.issn.1000-1093.2016.02.015

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Effect of narrowband interference suppression (NBI) on pseudorandom code zero value in PN code ranging system is presented. The equivalent filter model for classic NBI suppression algorithm is used to establish a model of analyzing the effect of NBI suppression on code phase bias. The relationship between the code phase zero value bias and equivalent filter characteristic is determined, and a simplified analytical model is proposed. Both theoretical analysis and simulations illustrate that the linear phase filter has no effect on code phase zero value; nonlinear phase filter has an effect on carrier phase zero value, which is directly related to the convolution results of the weights of filter and pseudo-code autocorrelation function.

Estimation of Equation of Motion of Four-rotor Dish-shaped AUV and Simulation Research on Its Hydrodynamic Characteristics

SONG Bao-wei, ZHANG Bao-shou, JIANG Jun, DU Xiao-xu, WANG De-zheng

2016, 37(2):  299-306.  doi:10.3969/j.issn.1000-1093.2016.02.016

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The four-rotor dish-shaped AUV is a new type of underwater vehicle. A three-dimensional model is set up to study the hydrodynamic characteristics of AUV, and the reference coordinate system and the generalized characteristic parameters are defined. In the body coordinate system, the concise six-degree-of-freedom dynamics and kinematics equations of motion for AUV are presented based on the momentum and the angular momentum theorem. The computational fluid dynamics method is used to simulate the hydrodynamic characteristics during the movement of AUV at the angles of attack from 0° to 90° based on fluid analysis software (Ansys CFX). The curves of drag, lift and pitching moment coefficients with the change of angle of attack are drawn. The simulated results show that, in the range of the angles of attack from 0° to 15°, the AUV is suitable for moving at a certain depth in the fluid with small fluid resistance. In the range of the angles of attack from 30° to 50°, the AUV is suitable to complete the curvilinear snorkeling motion with excellent lift characteristics.

Meso-scale Probabilistic Model of Fatigue Crack Nucleation Life

ZHOU Jin-yu, XIE Li-yang, ZHU Fu-xian, HAN Wen-qin

2016, 37(2):  307-316.  doi:10.3969/j.issn.1000-1093.2016.02.017

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Crack nucleation is an initial stage of damage evolution for high cycle fatigue of metallic material. Based on the Tanaka-Mura crack nucleation mechanism, a meso-scale probabilistic model is proposed for the analysis of surface crack nucleation life under constant amplitude loading. Let the grain size and Euler angle of crystal orientation be random variables, and the relationship between meso-scale principal stress and resolved shear stress is established by means of the Schmidt factor in the most possible sliding direction. The distribution function of resolved shear stress range is derived in consideration of grain orientation randomness and influence factors of nearest-neighbor grains. Furthermore, the probability density functions of crack nucleation lifes in any grain and grain group at the hotspot are derived by means of the moment method and order statistics models. A numerical example is given to show the feasibility and rationality of the proposed model and approach. The proposed model introduces probability statistic information of physical and geometrical variables on meso-scale, which can give a new path for probabilistic fatigue life assessment and anti-fatigue probabilistic design of polycrystalline metals structures.

Three-point Method and Error Analysis of Ballistic Range Calibration

WANG Wei, TANG Zhi-hua

2016, 37(2):  317-324.  doi:10.3969/j.issn.1000-1093.2016.02.018

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To avoid the difficulty from laser spot alignment of existing laser collimation system in calibration process, a system composition is simplified, the efficiency and accuracy of calibration are improved, and the adaptability of calibration system is enhanced. A transformation matrix between calibration system and ballistic range system is presented by using the coordinates of three non-collinear points in calibration system and ballistic range system. The mean value and the variance-covariance matrix of the final measuring error are studied by an error model founded by Jacobian matrix between the measuring and various error sources.The self-covariance of measuring error is studied based on the Cauchy-Schwarz inequality and the relationship between vector and matrix norms. An firing experiment of live ammunition is performed to verify the three-point calibration method of ballistic range. The research results show that the mean vector length of final measuring error about a point in ballistic range system is equal to the mean vector length of measuring error associated with same point in the calibration system; the larger the distance and the area surrounded by three non-collinear points which links the calibration system and ballistic range system together are, the smaller the self-covariance of the final measuring error is; the self-covariance decreases when the transition coordinate origin which is defined by the three non-collinear points is close to a projected trajectory line; based on the measurement method and the error of the three-point coordinates in ballistic system, the self-covariance of measuring error are changed when the calibration system origin moves away from the ballistic range system origin; and the calibration system based on the three-point method can be build-up by general instruments, and the quality of measured data is better.

Research on Detection Sensitivity Distribution Regularity of Lens-light-screen

TIAN Hui, NI Jin-ping, JIAO Ming-xing, HU Xun, GAO Fen

2016, 37(2):  325-331.  doi:10.3969/j.issn.1000-1093.2016.02.019

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In order to meet the testing requirement of indoor optical target with large detection area, two patterns of lens-light-screen’s engineering realization method are studied, of which one is sector lens-light-screen, and the other is rectangle lens-light-screen. The working principle of each kind of lens-light-screen is analyzed. The luminous flux may be changed when a flying projectile goes through the lens-light-screen in different position, of which the corresponding formulas are deduced based on the photometry principle. The sensitivity distribution regularity of each kind of lens-light-screen is simulated using Matlab. It is verified by the firing tests of air gun bullets. The results show that the signal amplitude of the projectile collected by an oscilloscope is in conformity with the sensitivity simulation results, which provides a reference for the engineering design of the optical targets with lager detection area.

Identification of Cross-section Loads Based on Measured Strain of Missile Body

LIU Yu-biao, XING Yun-lin, SHEN Zhong-han

2016, 37(2):  332-337.  doi:10.3969/j.issn.1000-1093.2016.02.020

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A pressing problem facing to missile designer is to identify the cross section loads of missile load by measured strains data which would be conveniently obtained in the flight test. A load identification method based on the measured strain data of the surface of the missile body is introduced to determine the equivalent bending moment and the axial force of the cross section. In order to eliminate the interference of the fault points of the measured data, a defect rejection principle based on linear correlation theory is presented to improve the reliability of the identification method. A verification test is designed to verify the accuracy and reliability of the identification method. Results show that the method has the high identification accuracy and can be applied to the engineering practice.

Research on Comprehensive Validation of Simulation Models Based on Improved Grey Relational Analysis

NING Xiao-lei， WU Ying-xia， YU Tian-peng， CHEN Wei-bo， SHAN Bin， ZHANG Yan

2016, 37(2):  338-347.  doi:10.3969/j.issn.1000-1093.2016.02.021

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Grey relational analysis (GRA) is usually used to validate the simulation models because of its advantage in the field of time series relational analysis. The ordinary GRA stresses the similarity but ignores the proximity between two test time series while the proximity is part of model error. The grey relational degree given by a set of flight test sequences and a set of simulation test sequences is inconsistent with the practical problems of firing range. The ordinary GRA cannot be used in the overall performance evaluation of simulation model, which leads to a high risk of decision-making. An improved grey relational analysis is proposed to reduce the risk, in which the similarity and the proximity between the simulation test time series and the flight test time series are considered. At the same time it can analyze the time series which has not only one dimension but also more than one dimension by calculating probability sum, and so it fuses random factor of random process and makes full use of simulation test data with small sample flying test. Besides the new grey relational analysis improves the performance of GRA and has higher precision and reliability for the validation of simulation models. The proposed model can be used to solve the relational analysis problem with many characteristics of behavior, and the operational steps are listed in detail. Data test and case study are given to show the reasonability and validity of the improved method.

Vector Matching-based Disturbance Torque Elimination Method

YANG Xue-song， LI Chang-chun， YAN Hao， HUANG Jing， LI Jing

2016, 37(2):  348-356.  doi:10.3969/j.issn.1000-1093.2016.02.022

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With the continuous development of manufacturing and drive technologies for electric motor, the electric motor is gradually taking the place of electro-hydraulic device, and becomes the preferred drive element of low and middle power level load simulators in the field of load simulation. There is similarity between the mathematical models of electric and hydraulic systems. The motor-hydraulic equivalent method is proposed, and the corresponding relation among the structure parameters of electric load simulator and the frequency domain characteristics of perturbance torque is obtained. The sweep test plays an important role in the electric load module test. According to the working conditions, a vector-based disturbance torque elimination method is put forward. The feasibility of the principle of the proposed method is verified by the AMESim simulation and the electric load simulation test stand. The test results show that the residual disturbance torque can be controlled within 1% of the rated load range (±15 N·m) of electric load simulator by the proposed method based on the amplitude-phase identification and genetic algorithm. Compared with other methods, the method is simpler, more flexible and adaptable. And it can be used to greatly improve the test accuracy of the load simulator suffered from the sinusoidal position disturbation.

Research Notes

Numerical Simulation about the Effect of Initial Separation Condition on Safety of Aerial Bomb Separated from an Aircraft

LEI Juan-mian， NIU Jian-ping， WANG Suo-zhu， ZHOU Qi

2016, 37(2):  357-366.  doi:10.3969/j.issn.1000-1093.2016.02.023

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In order to investigate the effect of initial release conditions on the safety of aerial bomb separated from aircraft, the separation process of aerial bomb from aircraft is simulated by using unsteady CFD numerical simulation method, dynamic mesh technique and 6-DOF trajectory equations. The trajectory and attitude variation of bomb after release are given under different conditions of Mach number, angle of attack, angle of sideslip, flight altitude, initial separation velocity and initial angular velocity. The results show that the aircraft has a strong aerodynamic interference on the bomb when separating, and has a great influence on the bomb's aerodynamic characteristics, trajectory and attitude. As the Mach number and angle of attack increase, the interference of aircraft on the bomb enhances, and the safety gets worse. For the bomb mounted under the left wing, a certain negative angle of sideslip is favorable to safe separation. The higher the flight altitude is, the safer the separation is. The certain initial separation speed and proper angular velocity are benefit for separation safety.

Numerical Compution of the Dynamic Derivatives of a Multi-wing Antitank Missile

YUE Jie-shun, WU Song-ping

2016, 37(2):  367-372.  doi:10.3969/j.issn.1000-1093.2016.02.024

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The methods of computing the dynamic derivatives are improved to estimate the unsteady aerodynamic characteristics of a multi-wing antitank missile. A quasi-steady state method is applied in computing the roll damping coefficient. The steady state flow is simulated by using sliding mesh technology. The unsteady pitch movement is simulated by using a reduced frequency method. In the movement, a far field velocity boundary condition is forced to oscillate.The computing procedures of roll and pitch damping moments are introduced based on these methods. These methods are applied to predict the dynamic derivatives of standard calibration model and a multi-wing antitank missile. The results indicate that the improved methods described have high accuracy and efficiency for the calculation of dynamic derivatives. And the improved methods are available for engineering applications.

Research on Characteristic Parameters of Ta-ZrO₂ Fiber Blackbody Cavity Temperature Sensor

HAO Xiao-jian，SANG Tao，PAN Bao-wu， ZHOU Han-chang

2016, 37(2):  373-378.  doi:10.3969/j.issn.1000-1093.2016.02.025

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In order to realize the transient high temperature measurement in the harsh environment and narrow space, a sapphire fiber tantalum (melting point 2 997 ℃) - zirconia (melting point 2 715 ℃) thin film black body cavity transient high temperature sensor is developed by the sputtering and plasma spray- ing technology. Constant high temperature static sensitivity calibration device, which is composed of three water electrolysis oxyhydrogen flame guns, and dynamic characteristic calibration device with high power and high frequency modulated CO₂ laser pulse as step excitation source are designed. The mea- sured results show that, when the temperature of constant temperature area of the static sensitivity calibration device is 1 721 ℃ and the impact resistance of the sensor is up to above 50 MPa, the temperature measured by the sensor is 2 802 ℃. When the CO₂ laser pulse is used as a high temperature step input signal at 1 500 ℃, the time constant measured by the sensor is μs order of magnitude.

The Optimization and Evaluation of Ballistic Missile Defense System Interception Scheme Based on Probability Model

GAO Ang, HU Yan-su

2016, 37(2):  379-384.  doi:10.3969/j.issn.1000-1093.2016.02.026

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How to design and deploy the interception schemes to meet the specific high-level defense objective is discussed. A correlation between defense objective and the number of interceptors is established based on Bernoulli trial model, and the effects of system generalized tracking ability and single-shot kill probability on the number of interceptors are analyzed as well. the factors, such as high-level defense objective, target number and single-shot kill probability, that affect consumption of interceptors at the modes of salvo fire and string firing are discussed. At the premise of defense objective, the interceptor allocation in a layered defense is modeled as an optimization problem. The average number of consumed interceptors can be minimized by optimizing the quantity of interceptors against the targets in each defense layer.