Table of Content

30 September 2021, Volume 42 Issue 9

Previous Issue    Next Issue

Contents

Contents

2021, 42(9):  0. 

Asbtract ( )   PDF (930KB) ( )  

Related Articles | Metrics

Paper

Microscopic Observation Mechanism of Nose Mass Abrasion of Kinetic Energy Projectile Penetrating into Reinforced ConcreteTarget at High Speed

NING Jianguo， LI Zhao， MA Tianbao， XU Xiangzhao

2021, 42(9):  1809-1818.  doi:10.3969/j.issn.1000-1093.2021.09.001

Asbtract ( )   PDF (9724KB) ( )  

References | Related Articles | Metrics

An obvious mass abrasion of kinetic energy projectile is generated in the process of high-speed penetration into concrete target. The mass abrasion seriously affects the penetration performance of projectile. A series of high-speed penetration experiments were carried out to further study the internal mechanism of projectile abrasion during penetration. The specimens for microscopic observation were prepared from the nose of residual projectile by linear cutting technique. The microstructures at multiple observation points on the surface of residual projectile were systematically observed by metallographic microscope and scanning electron microscope. The results show that there is an obvious heat affected zone on the surface of residual projectile，and there are many long grooves parallel to each other on its surface. In addition，a few microcracks are observed at the tip of projectile nose，which contribute to the mass loss of the tip of projectile nose，but have little influence. Through the microscopic observation，it is found that the mass abrasion of projectile is not caused by a single mechanism，but is a complex process of different mechanisms interacting with each other.

Effect of Launching Angle of Tank Gun on the Dynamic Behavior and Lubrication Performance of Turret Race

LI Junning, WANG Qian, HAN Ka, CHEN Wuge

2021, 42(9):  1819-1828.  doi:10.3969/j.issn.1000-1093.2021.09.002

Asbtract ( )   PDF (5276KB) ( )  

References | Related Articles | Metrics

The combined action of multi-directional forces, torques and heavy impact loads and the nonlinear rheological characteristics of grease in turret race can cause the dynamic evolution of its dynamic behavior and lubrication performance at the different launching angles, and then affect the firing accuracy and strike performance of tank gun. The force, contact radius and motion of the turret race were analyzed in considering the effect of the launching angle on the performance of turret race. On this basis, the distribution law of the maximum contact load of turret race at different launching angles was obtained by dynamics simulation. A contact lubrication performance analysis model based on dynamics and elastohydrodynamic lubrication theory was established for turret race. The changing laws of the pressure and oil film thickness in the contact area of turret race under the influences of different launching angles, load and rheological index were studied. The result show that the oil film pressure increases gradually and the oil film thickness decreases with the increase in the load. With the increase in rheological index, the secondary pressure peak of oil film became obvious and the oil film thickness increase. With the increase in the launching angle, the maximum contact load and the maximum oil film pressure tends to increase, and then the minimum oil film thickness tends to decrease, so the turret race has better performance when the launching angle is depression angle under the specific hitting capacity (recoil force) index.

The Influence of Electric Supercharger on Steady State Performance of Engine at Low Speed

YANG Pantao， CUI Tao， ZHAO Yankai， HE Wenqin， YU Congcong

2021, 42(9):  1829-1837.  doi:10.3969/j.issn.1000-1093.2021.09.003

Asbtract ( )   PDF (5349KB) ( )  

References | Related Articles | Metrics

Compared with turbocharging，the hybrid electric supercharging technology can improve the air intake volume and responsiveness of engine. The influence of rotating speed of electric supercharger on engine torque，air-fuel ratio and economy is studied to obtain the best working point of electric supercharger. The performance of electric hybrid supercharged engine is simulated based on the power, intake power and combustion effeciency of exhaust lurbocharger. The performance of hybrid electric turbocharged engine was compared with that of the original engine.The results show that the hybrid electric turbocharging system can effectively improve the performance of engine in the low rotating speed and high torque area，the low rotaing speed and high torque area of engine is increased by about 18%，and the fuel consumption is increased by about 16.7% in the area below 220 g/kWh; in the indicated power increment，the power increment of power cycle is far greater than that of the supercharging power;and the supercharging power increment is mainly increased by the supercharging power of the exhaust gas turbocharger. The main reason for the increase in turbocharging power is the enthalpy drop of exhaust gas turbine.

An Online Mass Estimation Algorithm for Single-shaft Parallel Hybrid Commercial Vehicle

MEI Cheng， PENG Jianxin， HU Yuhui

2021, 42(9):  1838-1846.  doi:10.3969/j.issn.1000-1093.2021.09.004

Asbtract ( )   PDF (4942KB) ( )  

References | Related Articles | Metrics

It is difficult for the automatic transmission controller of hybrid commercial vehicle to measure the total mass to optimize the shifting. An online mass estimation algorithm is proposed for the single-shaft parallel hybrid commercial vehicle. The parameter characteristics of vehicle's total mass during driving is analyzed，based on which the boundary conditions are set. A vehicle longitudinal dynamics model is established, and the working conditions of P2 hybrid system are studied. On this basis，the extended Kalman filter (EKF) algorithm is used to estimate the vehicle's total mass online. Cruise/Simulink co-simulation is realized by combining the vehicle model built in Cruise and the controller strategy model built in Simulink. Simulation tests and real vehicle tests were carried out. The test results show that the proposed algorithm can effectively identify the total mass of vehicle which satisfies the vehicle control requirements.

Dampling Characteristics of Projectile in Engraving Process of Nylon Sealing Band

CHENG Shenshen, TAO Ruyi, WANG Hao, XUE Shao, LIN Qingyu

2021, 42(9):  1847-1857.  doi:10.3969/j.issn.1000-1093.2021.09.005

Asbtract ( )   PDF (6688KB) ( )  

References | Related Articles | Metrics

A finite element model of the sealing band is established to research the mechanical properties of nylon sealing band of projectile launching from a large-caliber artillery during engraving process and analyze the influences of the the sealing bands with different structures on the engraving process. The pressure field is governed by an internal ballistic program，and the nonlinear mechanical behaviors are predicted based on the engineering software Abaqus. The pressure field and the structures through moving boundaries are coupled by using a user subroutine interface VUAMP in Abaqus. The different bottom radii and the nylon band structures with different widths and grooves were simulated and calculated. The simulated results show the mechanical properties and deformation evolution of band during the engraving process. The calculated results show that the larger the radius of projectile base is, the smaller the deformation space of band is and the greater the engraving resistance is. The sealing performance of band is improved with the increase in its width, but the resistance is also increased gradually. The sealing band groove can effectively change a single section of deformation into a multi-section of deformation, and the change of groove depth has a greater influence on the engraving resistance than the change of groove width.

Numerical Simulation on Size Effect of Hydroxyl Terminated Polyether Propellant Engine during Slow Cook-off

ZHANG Haijun， NIE Jianxin， WANG Ling， WANG Dong， GUO Xueyong， YAN Shi

2021, 42(9):  1858-1866.  doi:10.3969/j.issn.1000-1093.2021.09.006

Asbtract ( )   PDF (4314KB) ( )  

References | Related Articles | Metrics

The response processes of hydroxyl terminated polyether (HTPE) propellant engines with different sizes and length-to-diameter ratios were simulated to analyze the effect of structure size on their slow cook-off response characteristics. The temperature distribution, reaction temperature, reaction time and reaction location of propellant were studied. A calculation method based on image processing is established to calculate the temperature distribution of propellant before reaction of motor under slow cook-off. The temperature distribution is used as a parameter to evaluate the response intensity of slow cook-off. The results show that the engine diameter has a great influence on the reaction time and temperature of slow cook off, while the engine length has little effect on them. Both of them have great influence on the reaction position. With the increase in the size and length-to-diameter ratio, the reaction position moves to the edge of the charge. When the size is large enough, the distance between the reaction position and the shell edge remains stable. The mass ratio of high temperature propellant changes with the change of length-to-diameter ratio. When the charge diameter is 150-160 mm, the proportion of high temperature propellant before reaction is the smallest with charges of 5.5 kg, 18.0 kg and 44.0 kg, respectively.

Comparison of Released Energy and Coupling Damageability of Typical Reactive Alloy under High-speed Impact on Target

LI Mei, WANG Luyao, JIANG Jianwei

2021, 42(9):  1867-1876.  doi:10.3969/j.issn.1000-1093.2021.09.007

Asbtract ( )   PDF (9488KB) ( )  

References | Related Articles | Metrics

Reactive metal is a new type of high-density and ultra-insensitive energetic material, which can release a large amount of chemical energy under the high-speed impact, and has the potential of chemical energy to enhance kinetic energy damage. The reactive metal samples of amorphous alloys, traditional alloys, and high-entropy alloys are driven by a ballistic gun to hit the quasi-closed container and spaced targets at 1 500 m/s. The differences in the impact energy release behaviors and the coupling damageabilities of three samples to the spaced targets were compared and analyzed. The results show that the burning debris cloud formed after the reactive metal sample penetrates the target plate at high speed has both kinetic and chemical energy damageabilities to the spaced target. The chemical energy release efficiency is positively related to the static compressive strength of the sample. Since the chemical energy and kinetic energy carried by the sample move with the burning debris cloud and are released in different spaces behind the target, the damageability to the spaced target has nothing to do with the total energy carried. The contribution of chemical energy to the coupling damageability mainly depends on the energy release efficiency.

Influence of Lateral Acceleration on Ignition Transients of Solid Rocket Motor

GUAN Dian, LI Shipeng, LIU Zhu, WANG Ningfei

2021, 42(9):  1877-1887.  doi:10.3969/j.issn.1000-1093.2021.09.008

Asbtract ( )   PDF (6671KB) ( )  

References | Related Articles | Metrics

The high acceleration is found to alter the internal ballistic performance and induce ignition abnormalities by changing the internal flow and combustion state in the rocket chamber.To demonstrate the mechanism of interior ballistics as the results of acceleration loads imposed, the modes of the acceleration field effect, acceleration combustion effect, and erosion combustion characteristics are developed and first taken into in a new ignition model.The transient pressure in combustion chamber and the proportion of erosion and acceleration effects versus time are obtained. The relationship between propellant flame propagation speed and pressure rise rate is proposed. The results show that the peak-pressure is increased under the condition of positive acceleration and weakened under the condition of negative acceleration. Under the condition of positive acceleration, the front section of propellant is mainly affected by the acceleration-combustion, and the rear section is mainly affected by the erosion-combustion. By intensifying upstream combustion,the downstream erosion effect is aggravated by the positive acceleration. The negative acceleration is found with a less weakening effect on the combustion of propellant in the rocket, both in magnitude and time duration.The moment of peak of flame-spread velocity is almost identical to the moment of ignition of the entire propellant grain and the peak of pressure-rate.Therefore, the pressure-rise rate of the pressure data obtained in the experiment can be suggested to analyze the surface combustion of propellant.

Curing Reaction Kinetics and Process of PBX-based ATP

CHEN Chunyan， WANG Xiaofeng， NAN Hai

2021, 42(9):  1888-1894.  doi:10.3969/j.issn.1000-1093.2021.09.009

Asbtract ( )   PDF (3054KB) ( )  

References | Related Articles | Metrics

The curing test method and curing process of polymer bonded explosives（PBX）-based polyfunctional glycidyl azide polymer（ATP）were experimentally studied to set the curing process parameters. In the experiment，the non-isothermal differential scanning calometry method and rheological method were used to study the changes in curing heat and curing storage modulus，and the curing reaction kinetic equation and curing process parameters of PBX were obtained. The experimental results show that the rheological method can be used to characterize the curing reaction of PBX，the reaction kinetic equation is dαdt=2.0×10 ¹⁹exp [JB<2(]－1.51×10 ⁵RT[JB>2)]α^0.42·(1－α) ^1.30. When the ATP-based PBX is cured directly at 60 ℃，a large number of pores appear in PBX，the 30 ℃ and 60 ℃ step curing process is adopted without pores in the PBX; the optimal curing time of ATP-based PBX at 30 ℃ is 68 h，and the optimal curing time at 60 ℃ is 66 h.

Identification and Correction Method of Material Parameters of Dummy's Lower Limbs Subjected to Impact of Explosive Load

LI Mingxing， ZHANG Ming， CHEN Sichun， LI Kai， LIU Zhuang， YUAN Xi

2021, 42(9):  1895-1901.  doi:10.3969/j.issn.1000-1093.2021.09.010

Asbtract ( )   PDF (4532KB) ( )  

References | Related Articles | Metrics

The constitutive parameters of the dummy's lower limb material subjected to high-speed vertical impact are checked and optimized to improve the simulation accuracy of dummy under the impact of explosive load. In view of the structural response characteristics of vehicle body subjected to explosion shock wave load, the impact velocity of simulated explosion load impacting the test bench is determined. The impact test of dummy’slower limbs is carried out by setting different impact speeds to obtain the impact force-time curves of the lower limbs. The important material parameters of lower limbs are experimentally designed and the peak value of simulated lower limb tibial force is obtained to optimize the lower limb material parameters with the goal of minimizing the error between the simulated data and the experimental data. Through bench test and finite element numerical simulation verification, the material parameters are optimized, and the best matching of the material constitutive model parameters are obtained for the components of the lower limbs. The results show that the simulated results after optimizing the material parameters of the dummy's lower limb model are in good agreement with the test results, which can provide technical support for the revision of the dummy lower limb material model under high-speed vertical impact.

Optimal Time Resource Allocation Algorithm for Surveillance Phased Array Radar Target Tracking Based on Bayesian FilteringAlgorithm

LI Jisan， HOU Jiao， LIU Rong， REN Yuan

2021, 42(9):  1902-1910.  doi:10.3969/j.issn.1000-1093.2021.09.011

Asbtract ( )   PDF (2706KB) ( )  

References | Related Articles | Metrics

For the optimal time resource allocation for target tracking of surveillance phased array radar，a variable data rate tracking algorithm is proposed based on Bayesian filtering algorithm. The adaptive data rate algorithm causes the tracking data rate to jitter due to the fluctuation of the measured noise in the uniform linear motion stage of target，but leads to losing the track of target in the reverse maneuvering stage of target. In the proposed algorithm, the normal distribution criterion is used to judge whether the target is maneuvering in the non-maneuvering phase, and the target acceleration obeys the corrected Rayleigh distribution in the maneuvering phase. The proposed algorithm uses different smoothing coefficients in the increasing and decreasing stages of data rate, thus enabling the quick response of target maneuver and ensuring to track a target in the reverse maneuvering phase. The simulated results of two maneuvering examples show that the proposed algorithm can effectively suppress the mismatch problem of target reverse maneuvering. Compared with the traditional Cohen algorithm, the new algorithm can quickly respond to target maneuver.

Infrared and Visible Images Fusion based on Non-subsampled Contourlet Transform and Guided Filter

DING Guipeng， TAO Gang, LI Yingchao, PANG Chunqiao, WANG Xiaofeng, DUAN Guiru

2021, 42(9):  1911-1922.  doi:10.3969/j.issn.1000-1093.2021.09.012

Asbtract ( )   PDF (12031KB) ( )  

References | Related Articles | Metrics

An image fusion method based on non-subsampled contourlet transform (NSCT) and guided filter is proposed to overcome the shortcomings of traditional fusion methods for infrared and visible images with weak gray correlation. The source images are decomposed into multi-scale and multi-directional sub-bands using NSCT, which can separate the feature information contained in different frequency domains to obtain a low-frequency approximate image and the high-frequency directional sub-band images. The local window weighted average energy and sum-modified-Laplacian energy are regarded as the activity measures of low frequency approximate image, respectively, which are used to construct a salient feature map to solve the two key problems of energy preservation and detail extraction. In the directional sub-band image, the maximun activity measure rule is used to obtain the decision maps, the source images are taken as the guided images, and the decision maps are used as the input images for guided filtering. The weight distribution graph is obtained to weight and average the directional sub-band images to reduce the noise sensitivity. Finally, the fused approximate and directional sub-band images are reconstructed by non-subsampled contourlet inverse transform, and the final fusion image is obtained. Some fusion experiments on several sets of infrared and visible images were did, and the objective performance assessments were implemented to fusion results. The experimental results indicate that the proposed method performs better in subjective and objective assessments than a few existing typical fusion techniques，such as guided filter fusion method based on two-scale decomposition, sparse representation fusion method in NSCT domain, cross bilateral filter fusion method based on pixel saliency, convolution neural network fusion method based on deep learning, two-scale fusion method based on saliency detection, and obtains better fusion performance.

Passive Target Positioning Algorithm for Mixed Noise

CHEN Linxiu， HAO Mingrui， ZHAO Jiajia

2021, 42(9):  1923-1930.  doi:10.3969/j.issn.1000-1093.2021.09.013

Asbtract ( )   PDF (2739KB) ( )  

References | Related Articles | Metrics

An adaptive cubature Kalman filter(ACKF) algorithm is proposed to improve the filtering accuracy and stability of the cubature Kalman filter(CKF) algorithm when the passive sensor measurement noise is a mixed noise containing time-varying colored noise and jumping noise. Based on the basic CKF algorithm, the measurement reconstruction and undetermined coefficient decorrelation methods are used to derive the cubature Kalman filter algorithm with colored measurement noise (CKF-CMN). For the impaired filtering accuracy caused by time-varying colored noise and jumping noise, the idea of online correction of noise variance and removal of harmful measurement is introduced, and the ACKF algorithm is designed. The simulated results show that, compared with the basic CKF algorithm, the passive positioning accuracies of ACKF algorithm on x, y, and z axes are increased by 24.75%, 32.57% and 28.48%, respectively. The ACKF algorithm has higher filtering stability and accuracy.

Coarse Tracking Technology of Coude-type Laser Communication Terminal

BAI Yangyang, CHEN Libing, MENG Lixin, ZHANG Leyi, ZHANG Lizhong

2021, 42(9):  1931-1939.  doi:10.3969/j.issn.1000-1093.2021.09.014

Asbtract ( )   PDF (7064KB) ( )  

References | Related Articles | Metrics

Since telescopic units and Coude mirrors move relative to the CCD detectors in the Coude-type laser communication terminal，the optical path structure of the whole system will change with the change in posture of communication terminal，which leads to the increased control difficulty of laser communication terminal system. To solve this problem，a CCD angle measurement model of the Coude-type laser communication terminal is established and deduced by using matrix optics method，and the control algorithm is optimized on this basis. Firstly，the experimental conditions are set up，and the angle measurement model is statically verified by using the measured data. The static calculation accuracy is better than 9 μrad. Then an automatic tracking algorithm based on the model is designed. The standard deviation of measured dynamic tracking error is better than 21 μrad（1σ） by adding sinusoidal disturbance signal with angular velocity of 0.1°/s and amplitude of 0.1° to meet the requirement of laser communication for tracking accuracy of 50 μrad（1σ） .

Siamese Network for Visual Tracking with Temporal-spatial Property

JIANG Shan， DI Xiaoqiang， HAN Cheng

2021, 42(9):  1940-1950.  doi:10.3969/j.issn.1000-1093.2021.09.015

Asbtract ( )   PDF (8953KB) ( )  

References | Related Articles | Metrics

A siamese network with temporal-spatial attention mechanism is proposed to tackle the problem of poor accuracy in dealing with fast motion and background clutter in the current algorithms. A temporal attention module is designed， the features of multi-frames are fused according to the contribution of each reference frame，and the weights are assigned adaptively to construct an effective temporal fused template. The spatial attention module is adopted to percept the whole tracking image by non-local operation，which can improve the discriminative ability of the network. During the training stage， the Focal Loss is utilized to train the network model，which can balance the proportion of positive and negative samples，and improve the ability of model to distinguish the hard samples. Several simanation experiments were conducted on the OTB2015 and VOT2016 benchmark to evaluate the performance of the proposed algorithm，and compared it with the state-of-the-art algorithms, i.e., ECO, DSST, HDT, CFNet, KCF, SRDCF, SiamFC, DCFnet, MEEM, SiamVGG, BACF and ANT algorithms. The experimental results demonstrate that the proposed siamese network tracking model with temporal-spatial attention property can well handle the fast motion and background clutter situation，and effectively improve the performance of baseline algorithm.

A Magnetic Gradient Tracking Method for Target Tracking and Characteristics Inversion

MA Jianfei， DING Kai， YAN Bing， LIN Chunsheng

2021, 42(9):  1951-1961.  doi:10.3969/j.issn.1000-1093.2021.09.016

Asbtract ( )   PDF (4452KB) ( )  

References | Related Articles | Metrics

The traditional positioning methods with magnetic gradient tensor are basically based on single magnetic dipole model，which results in insufficient positioning accuracy. Moreover，these positioning methods are easily affected by environmental noise and measurement accuracy. Especially in the dipole characteristic plane，little disturbance or insufficient observation accuracy will lead to a big deviation of positioning results. A new magnetic gradient tracking method for scale magnetic targets is proposed based on the combination model of multiple dipoles and the robust nonlinear Huber unscented Kalman filter. The proposed method can effectively improve the positioning accuracy of scale magnetic targets，especially when abnormal observation occurs，it can still accurately locate the target. In order to identify targets such as mines or underwater unexploded projectiles，and considering the mathematical meaning of principal component analysis (PCA)，a inversion algorithm based on the dipole distribution obtained by NHUKF algorithm is proposed. The inversion algorithm can identify the main scale as line structure or surface structure，and the inversion error of main scale is less than 0.3 m，the inversion error of the direction is less than 2 degrees，which provides a reference for the target classification.

An Analytical Predictive Control Anti-pitching Method for a High-speed Multi-hulled Vessel

ZHANG Jun， WEN Hao， LIU Zhilin， LI Guosheng

2021, 42(9):  1962-1971.  doi:10.3969/j.issn.1000-1093.2021.09.017

Asbtract ( )   PDF (4762KB) ( )  

References | Related Articles | Metrics

A fast analytic predictive control anti-pitching method is proposed to reduce the amplitudes of heaving and pitching changes of high-speed multi-hulled vessel and improve the stability of hull vertical motion.A vertical motion model is established for high-speed multi-hulled vessel with T-foil and flap severed as anti-pitching appendages，and the strong coupling of heaving/pitching motions and model uncertainty are analyzed. With the establishment of objective function and terminal equality constraint of continuous predictive control，the first-order Euler model with error feedback correction is used to predict the heaving/pitching motions，thus improving the accuracy and anti-pitching control performance of prediction model. On this basis，the numerical integration method and optimal quadratic programming theory are used to obtain the analytical predictive control law for vertical stabilization of high-speed multi-hulled vessel，thus significantly reducing the complexity of online optimization.The uniform boundedness of the closed-loop system is theoretically proved based on the Lyapunov theory. The anti-pitching performances of the analytical predictive control method and other generalized predictive control methods are compared through simulation，and the effectiveness of the proposed algorithm is verified through experiment.

Hydrodynamic Coefficients Calculation and Dynamic Modeling of an Open-frame Underwater Robot

YAN Yinpo， YU Fujie， CHEN Yuan

2021, 42(9):  1972-1986.  doi:10.3969/j.issn.1000-1093.2021.09.018

Asbtract ( )   PDF (9437KB) ( )  

References | Related Articles | Metrics

A numerical calculation method for hydrodynamic coefficients based on lattice Boltzmann method (LBM) is proposed for studying the maneuverability prediction and control algorithms of open-frame underwater robot.The steady-state surge motion simulation test and oblique towing simulation test were carried out based on LBM and Reynolds-averaged Navier-Stokes(RANS) methods, respectively, and the feasibility of LBM method was verified by comparing the test results.The motion mathematical models of large amplitude planar motion mechanism(PMM) tests and the hydrodynamic models, including inertial hydrodynamic coefficients, linear and nonlinear viscous hydrodynamic coefficients, were established according to the structural characteristics of remotely operated vehicle(ROV), and the hydrodynamic coefficients in the hydrodynamic models were obtained by using least square method. The standard maneuverability simulation tests were performed, which verifies the validity of the 6-DOF motion equation with hydrodynamic coefficients.Compared with traditional CFD methods, the proposed hydrodynamic coefficients calculation method is not limited by the shape complexity of underwater robot, and the updating issue of complex dynamic mesh in unsteady-state motions simulation is avoided. The calculation period of hydrodynamic coefficients is shortened by the large amplitude PMM simulation tests，and the proposed dynamic model is more available for the research of maneuverability and control algorithms.

Simulation Design of Camouflage Target Concealing Strategy Based on Evolutionary Computation

ZHOU Ying， XIE Zhenping， JIANG Xiaojun

2021, 42(9):  1987-1997.  doi:10.3969/j.issn.1000-1093.2021.09.019

Asbtract ( )   PDF (13598KB) ( )  

References | Related Articles | Metrics

For the concealment problem of military equipment in typical natural environment， a novel simulation design method is proposed by combining a modified evolutionary computation strategy and image simulation design technique. The proposed method contains following parts: the fusion simulation computation of camouflage objects and scene images，the camouflage target concealment strategy simulation using optical illusion strips coverage，the search computation based on particle swarm optimization algorithm and probability distribution sampling algorithm，and the calculation of fusion degree between camouflage objects and background scenes based on deep neural network image features. Based on the deep neural network image segmentation model，the recognition rate of camouflage target segmentation is introduced to evaluate the performance of the proposed method. Simulation experimental result shows that the average fusion degree of concealment simulation images obtained in woodland and desert environment can reach above 0.99，and the average segmentation recognition rate of camouflage targets is lower than 0.90. The proposed method can provide very effective results for designing the concealment strategy of a given target in a scene image，and has good practical value and scalability.

Simulation Technology for False Performance of Decoy Tank Based on Three-dimensional Modeling

FENG Haichao， WANG Yuyu， LIU Wei， ZENG Yongxing， WU Kenan

2021, 42(9):  1998-2003.  doi:10.3969/j.issn.1000-1093.2021.09.020

Asbtract ( )   PDF (3081KB) ( )  

References | Related Articles | Metrics

In order to improve the test efficiency of decoy target in visible band and reduce the test risk， the three-dimensional modeling and simulation technology are used to replace the real tank with a simulated tank for the performance test of decoy tank. The 3D point cloud data of the simulated tank is collected by using the 3D modeling technology，and the main components of the tank are modeled in an appropriate way.The digital camouflage pattern is mapped to the 3D simulation model using the flexible mapping method to complete the construction of the simulated tank. Through coordinate transformation and perspective projection transformation，the 3D tank model and 2D background are synthesized to obtain a simulation experimental image. Through the calculated result of the similarity between the real tank and the simulated tank in the simulation experimental image and the statistical results of interpreter，it is shown that the simulation technology is feasible for the equipment test.

Slope Measurement Method for Three-dimensional Residual Stress in 7075-T651 Aluminum Alloy Plate

WANG Zibiao， SUN Jianfei， LI Tian， ZHANG Liren， ZHANG Shengwei

2021, 42(9):  2004-2012.  doi:10.3969/j.issn.1000-1093.2021.09.021

Asbtract ( )   PDF (3073KB) ( )  

References | Related Articles | Metrics

In order to improve the performance and reliability of airplane and reduce its weight，the aluminum alloy monolithic structure parts are increasingly used in the aviation industry. The initial residual stress (IRS) is a crucial factor influencing the machining deformation of aluminum alloy monolithic structure parts. The effective research on deformation depends on the accurate and efficient measurements of IRS. The traditional layer-removed method for the residual stress measurement is time consuming as it requires the repeated gluing and removing of strain gauge. An innovative slope method is proposed to measure the three-dimensional IRS of the pre-stretched aluminum alloy plate. The measured results must be modified in order to reduce the measurement errors. The profiles of residual stress measured by two methods are like double M type curves. The slope method raises the measurement efficiency by tenfold compared with the traditional layer-removed method. About 90% of all the absolute errors of residual stress corrected by two methods are within 6 MPa. The slope method is used to measure the residual stress across the thickness of workpiece, and also abtain the residual stress of subsurface within 20 μm.

Tool Wear Prediction Based on Fusion Evaluation Index and Neural Network

QIN Guohua， GAO Jie， YE Haichao， JIANG Guojie， HUANG Shuai， LAI Xiaochuun

2021, 42(9):  2013-2023.  doi:10.3969/j.issn.1000-1093.2021.09.022

Asbtract ( )   PDF (3845KB) ( )  

References | Related Articles | Metrics

Tool wear has a great influence on the machining quality，production efficiency and cost of parts in the process of machining. The reasonable and accurate noise reduction for collected tool wear signal is the core technology for tool wear detection. Based on the weights of the signal-to-noise ratio，the smoothness and the mean square root error which are constructed by the entropy method，the fusion evaluation index of noise reduction quality is proposed. Comparison of the denoised simulated signal with the real signal shows that the fusion evaluation index is of the feasibility and superiority. And then an optimization method of noise reduction parameters is presented with the objective of maximum fusion evaluation index. For the actual vibration signal of tool wear after wavelet threshold denoising，the noise reduction parameters optimized by the fusion evaluation index proposed in this paper can be used to remove the noise signals at high frequency \[6 kHz，12 kHz\] and also retain completely the real signals at low frequency \[0 kHz，6 kHz\] compared with the traditional single evaluation index. Finally，a neural network prediction model is established from the extracted feature values of tool wear for describing the relationship between the tool wear and the cutting parameters. Experimental results show that the tool wear signal features can be accurately extracted using the optimal noise reduction parameters based on multi-index fusion evaluation. The maximum error between the predicted values and the measured values is no more than 6.0%.

Tool Wear Online Monitoring Based on Multi-sensor Information Decision-making Level Fusion

LI Heng, YE Zukun, ZHA Wenbin, WANG Yulin

2021, 42(9):  2024-2031.  doi:10.3969/j.issn.1000-1093.2021.09.023

Asbtract ( )   PDF (2669KB) ( )  

References | Related Articles | Metrics

An online dynamic monitoring model of tool wear based on multi-sensor information decision-making level fusion is proposed for accurately controlling the tool wear state in the machining process. After extracting the time, frequency and time-frequency features from the collected vibration, force and acoustic emission sensor signals, the monitoring model divides the sensor signal features into independent samples according to the sensor type. The same tool wear extent is regressively predicted using the independent samples, respectively. Then the tool wear extent predicted from the signal characteristics of each sensor is comprehensively determined. Finally, the tool wear extent is determined. The experimental results show that the on-line dynamic monitoring model of tool wear can effectively improve the accuracy of tool wear dynamic prediction, and the average prediction accuracy is 97.9%. Compared with existing research methods, the proposed method is used to increase the prediction accuracy rate by at least 4%, and the prediction time is only 0.016 s.

Optimization of Vehicle Maintenance Process Scheduling under Limited Resources

TANG Runzhi, BAN Liming, QIAN Le, LEI Zhengjun, SONG Weixing

2021, 42(9):  2032-2039.  doi:10.3969/j.issn.1000-1093.2021.09.024

Asbtract ( )   PDF (1691KB) ( )  

References | Related Articles | Metrics

The tight schedules, a large number of tasks, and many emergencies will arise for the maintenance of vehicles during wartime. Vehicle maintenance scheduling has an important effect on the recovery of military combat effectiveness. The existing maintenance scheduling methods mainly focus on a single constraint condition for process optimization, which is difficult to meet the actual support requirements. A multi-objective optimization function that integrates multitiple work types and multi-personnel technical level elements is presented according to the size of actual maintenance team, and an improved non-dominated sorting genetic algorithm (NSGA-Ⅱ) based on elitist strategy is established by taking the single process man-hours, total man-hours, immediate predecessor activity, and total human resources as the constraint conditions. In the proposed algorithm, a binary tournament selection operator is added based on the traditional non-dominant elite strategy, and the crossover operator for the multi-objective function optimization is redesigned, and the double coding is used to calculate and solve the preemptive maintenance process scheduling mode. The simulation verification with actual maintenance cases shows that the proposed method is used to reduce the maintenance time and achieves the goal of optimizing the efficiency of human resource scheduling under the conditions of meeting the optimization of complex objectives in wartime.

Multi-target Assignment and Intelligent Decision Based on Reinforcement Learning

ZHU Jianwen, ZHAO Changjian, LI Xiaoping, BAO Weimin

2021, 42(9):  2040-2048.  doi:10.3969/j.issn.1000-1093.2021.09.025

Asbtract ( )   PDF (2580KB) ( )  

References | Related Articles | Metrics

A reinforcement learning-based swarm intelligent decision-making method of cooperative multi-target attack under high-dynamic situation is proposed. The composite evaluation criteria of attack performance is established, including the evaluation of attack superiority based on relative motion information and the threat evaluation based on the inherent information of target. To evaluate the attack-defence effectiveness, a cost-effectiveness ratio index is designed by combining attack performance, penetration probability and attack cost together. In addition, a multi-target decision-making architecture based on reinforcement learning is constructed, and an action space with allocation vectors as basic elements and a state space based on quantified performance indicators are designed. Q-Learning is employed to make intelligent decisions on cooperative attack plans, including missile selection and target assignment. The simulated results show that reinforcement learning can achieve multi-target online decision-making with the optimal offensive and defensive effectiveness, and its computational efficiency has more obvious advantages than that of particle swarm optimizer.