Table of Content

31 July 2024, Volume 45 Issue 7

Previous Issue   

Electronic edition of this issue

Electronic edition of this issue

2024, 45(7):  0. 

Asbtract ( )   PDF (219334KB) ( )  

Related Articles | Metrics

Contents

Contents

2024, 45(7):  0. 

Asbtract ( )   PDF (1046KB) ( )  

Related Articles | Metrics

Research on Armored Vehicle Detection Algorithm Based on Visible and Infrared Image Fusion

CHANG Tianqing, ZHANG Jie, ZHAO Liyang, HAN Bin, ZHANG Lei

2024, 45(7):  2085-2096.  doi:10.12382/bgxb.2023.0401

Asbtract ( )   HTML ( )   PDF (8772KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The armored vehicle detection algorithm based on visible images is easily interfered by the complex ground environment. An armored vehicle detection algorithm based on fusion of visible and infrared images is proposed. The features of visible image and infrared image are adaptively fused by a convolutional neural network, which improves the detection accuracy of armored vehicle in complex ground environment. A visible-thermal armored vehicle (VTAV) dataset is constructed through on-site photography for the detection task of armored vehicle in complex ground environment. Based on the classic one-stage anchor-free detection algorithm, three fusion structures called early feature fusion, middle feature fusion and late feature fusion, are designed, and two different fusion methods are proposed. The detection performances of different fusion structures and fusion methods are compared on the VTAV dataset. The experimental results show that the peroformce of late feature fusion structure is the best, and compared to the armored vehicle detection algorithm based on visible image, mAP@0.5∶0.95 is increased by 2.6 %. The armored vehicle detection algorithm based on fusion of visible and infrared images has been proven to effectively improve the detection accuracy in complex ground environment.

Local Path Planning for Unmanned Ground Vehicles Based on Improved Artificial Potential Field Method in Frenet Coordinate System

JI Peng, GUO Minghao

2024, 45(7):  2097-2109.  doi:10.12382/bgxb.2023.0305

Asbtract ( )   HTML ( )   PDF (7972KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The artificial potential field method is widely used in the local path planning for unmanned ground vehicle (UGV) due to its small amount of computation and high accuracy. For the problems of target unreachability, local minimum and falling into U-shaped obstacles existing in the conventional artificial potential field method, a local path planning algorithm based on the improved artificial potential field method in Frenet coordinate system is proposed. In this paper, the Frenet coordinate system is used to describe the UGV’s obstacle avoidance movement, which simplifies the planning model and addresses the difficulty in expressing the relative position of UGV and the road during path planning. A safety ellipse model and the concept of prediction distance are proposed to adjust the influence area of the potential field. Additionally, the repulsive field function is improved by adding the reference line potential field and the dynamic velocity potential field based on the Frenet coordinate system. These modifications enable the UGVs to avoid obstacles under both static and dynamic conditions. The path planning methods are proposed to launch the static and dynamic obstacle avoidance simulation experiments with different vehicle speeds in straight and curved road scenarios using mathematical simulation software. The results demonstrate that the front wheel turning angle and traverse angular velocity at different vehicle speeds are controlled within a small range, and the improved algorithm can effectively solve the defects of the conventional artificial potential field method. Besides, compared with the rapidly-exploring random tree(RRT) algorithm, the computational efficiency of path planning of the improved algorithm in the obstacle avoidance process is improved by 42.8%, and achieves better computational performance.

Potential Field Exploring Tree Path Planning for Intelligent Vehicle in Off-road Environment

TIAN Hongqing, MA Mingtao, ZHANG Bo, ZHENG Xunjia

2024, 45(7):  2110-2127.  doi:10.12382/bgxb.2023.0132

Asbtract ( )   HTML ( )   PDF (13825KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Path planning is a key technology for intelligent vehicles. The traditional vehicle path planning method takes the shortest traveling distance or minimum traveling time as the optimization goal, ignoring the risk of vehicle motion. A potential field based rapidly-exploring random tree (RRT) algorithm is proposed. The potential field model is used to quantitatively evaluate the driving risk, and a low-risk initial vehicle driving trajectory is obtained efficiently using the RRT algorithm. And then a trajectory reconstruction optimization method is adopted to continuously optimize the vehicle driving trajectory based on the driving safety, traveling distance and turning angle. The scenario simulation is used to verify the performance of the planning solution. The simulated results show that the proposed algorithm can balance the path planning efficiency and safety performance, while avoiding the obstacles and environmental threats in off-road environment. The planned trajectories conform to the vehicle kinematics features, good safety and high traveling efficiency.

A Method for Military Aircraft Recognition Using a Coordinate Attention-based Deep Learning Network

YANG Huanyu, WANG Jun, WU Xiang, BO Yuming, MA Lifeng, LU Jinlei

2024, 45(7):  2128-2143.  doi:10.12382/bgxb.2023.0526

Asbtract ( )   HTML ( )   PDF (10993KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The military combat information can be provided by using the visible images to effectively distinguish the types of enemy aircrafts used for military operations in a rapidly changing battlefield environment. To address the challenges associated with extracting the model features from small aircraft targets and complex environmental backgrounds, as well as the limited training data available in existing military aircraft recognition methods, this paper proposes a ConvNeXt with coordinate attention(ConvNeXt-CA)-based recognition method for military aircraft targets. Based on the fact that the ConvNeXt-CA network can retain the characteristics of small aircrafttargets, the proposed method introduces the CA mechanism to design a CA-Stage module, which improves the ability of the network to distinguish between background and foreground.It uses data augmentation to expand the data set and the migration learning strategy to improve the generalization capability of the model, and trains the ConvNeXt-CA network with optimal hyperparameters.The experimental results show that, compared with the traditional military aircraft identification methods and other deep learning models, the migration learning-based ConvNeXt-CA network has a significantly improved prediction accuracy and a strong generalization capability.

Surface Electromyography-based Human Motion Pattern Recognition Using Convolutional Neural Networks

LIU Yali, LU Yanchi, MA Xunju, SONG Qiuzhi

2024, 45(7):  2144-2158.  doi:10.12382/bgxb.2023.0125

Asbtract ( )   HTML ( )   PDF (7228KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Along with the rapid development of surface electromyography (sEMG)-controlled devices, such as exoskeleton robots, the application of non-stationary and aperiodic signals in advanced high-performance motion recognition system has become a notable focus in relevant fields. To achieve the cross-domain feature fusion of sEMG, a dual convolutional chains neural network based on sEMG signals is proposed. Raw sEMG signals of seven key differentiated muscles are collected and processed by feature extraction methods, and converted into energy kernel phase diagram and discrete wavelet transform coefficient feature map, which are respectively input into the CNN branch and the MobileNetV2 branch of dual convolutional chains neural networks. The extracted high-level hidden features are processed by the fusion module for full interaction. Three datasets, including the above two feature images and conventional electromyography spectrum, are prepared. Three sets of cross experiments show that the average recognition accuracy of the proposed method for six self-tested lower limb movements is 94.19%, which is significantly better than other feature combinations and network architectures. Meanwhile, seven lower limb movements are identified with 98.32% steady-state recognition accuracy in ENABL3S open source dataset, further proving that the proposed method has excellent sEMG feature capture ability and pattern recognition accuracy.

Magnetic Field Analysis and Thrust Fluctuation Optimization of Permanent Magnet Synchronous Linear Motor for Electromagnetic Launch

JIA Guangyong, SUN Zhaolong, HUANG Chuibing, ZHOU Weichang, MAO Yinhao, LEI Zhaoran

2024, 45(7):  2159-2170.  doi:10.12382/bgxb.2023.0252

Asbtract ( )   HTML ( )   PDF (6947KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The magnetic field analysis and thrust fluctuation optimization of a permanent magnet synchronous linear motor for electromagnetic launch are performed by establishing an analytical model of the magnetic field of a single-sided motor for electromagnetic launch. The magnetic fields of the secondary Halbach permanent magnet array and the primary six-phase winding are analyzed to obtain the air-gap magnetic field distribution by using the vector magnetic potential and boundary conditions, and then the functional relationship between the electromagnetic thrust and the main structural parameters of single-sided motor is established. The pole arc coefficient and thickness of permanent magnet array, and width and thickness of primary winding are selected as optimization variables, and the optimal combination of design variables is found by using genetic algorithm to minimize the ripple of the unilateral electromagnetic thrust of single-sided motor. The analysis shows that the accuracy of magnetic field analysis results is high, and the calculation error of electromagnetic thrust meets the needs of engineering analysis. The average thrust of the optimized single-sided motor is increased by 1.21%, and the peak-to-average force ratio is decreased by 62.688%. The correctness of theoretical derivation and the rationality of the optimization method are verified by comparing the analyzed and simulated results.

Multi-platform Networked Guidance Handover Technology

ZHANG Kun, HUA Shuai, YUAN Binlin, LI Yang

2024, 45(7):  2171-2181.  doi:10.12382/bgxb.2023.0216

Asbtract ( )   HTML ( )   PDF (5712KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Aiming at the actual demand of multi-platform networked cooperative guidance missile to hit the target, and the problem of abnormal overload mutation in the process of missile handover, the key error of networked guidance is analyzedbased on the process of multi-platform handover, the mechanism of abnormal overload mutation of missile is clarified, and a basic model of networked guidance handover is established. Aiming at the information handover error, a virtual target networked guidance information handover method based on uniform acceleration and deceleration is designedbased on the handover method of virtual target information,. Finally, aiming at the problem of guidance law difference during handover execution, a missile guidance handover control law in multi-platform cooperative guidance mode is proposed based on virtual target information. The simulated results show that the proposed method can be used to effectively reduce the abnormal overload caused by the error of target information captured by the cooperative guidance platform, realize the smooth transition of overload during the missile handover process under the change of the guidance rate, and effectively improve the combat effectiveness.

Dynamic Modeling and Attitude Control for Novel Agile Projectile

ZHAO Xinyun, YU Jianqiao

2024, 45(7):  2182-2196.  doi:10.12382/bgxb.2023.0404

Asbtract ( )   HTML ( )   PDF (3376KB) ( )  

Figures and Tables | References | Related Articles | Metrics

A dynamic modeling and attitude control method for novel agile projectiles is proposed to improve the large-angle maneuverability of the projectiles. By adding a flexible and controllable circular parachute to the tail of the traditional reaction-jet and aerodynamic compound control agile projectile, a geometric configuration of the novel agile projectile is designed, and the novel agile turn is divided into three phases. To avoid a series of problems caused by Newton-Euler’s mechanics in solving complex constraints in the process of multi-body dynamics modeling, based on Lagrange mechanics, the position and attitude of projectile and the attitude of parachute are selected as the generalized coordinates, the kinetic energy of the system is derived, and the generalized force of the system is solved. Then a four-degree-of-freedom dynamic model with projectiles as the main body in the vertical plane is established. Finally, in order to design the flexible force, reaction-jet and aerodynamic compound control law for novel agile projectiles with fast time variability, strong uncertainty and strong nonlinearity, the equation of state for the system attitude tracking error is established, and the attitude controller with finite time convergence is designed based on the non-singular terminal sliding mode and the double power reaching law. The extended state observer is used to eliminate the negative impact of internal and external disturbances on the system and suppress chattering. The rationality and effectiveness of the proposed method are verified through simulation. Through the simulation and comparison of the novel and traditional agile projectiles, it is verified that the proposed method is beneficial for reducing turning radius, shortening turning time, and reducing energy consumption.

A High-spinning Projectile Aerodynamic Modeling Method Combining System Identification and Transfer Learning

JI Wen, LI Chunna, JIA Xuyi, WANG Gang, GONG Chunlin

2024, 45(7):  2197-2208.  doi:10.12382/bgxb.2023.0127

Asbtract ( )   HTML ( )   PDF (6814KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Computational fluid dynamics andrigid body dynamics(CFD/RBD) coupling simulation is a common method for evaluating the flight performance of spinning projectiles, which is quite inefficient due to huge amount of CFD simulations. An efficient and accurate aerodynamic model with strong generalization ability is established to significantly improve the simulation efficiency by replacing the CFD module in coupling simulation. An aerodynamic modeling method combining system identification and transfer learning is proposed to address the above-mentioned problem. First, the samples of spinning projectile are obtained by CFD/RBD coupling simulations under the given initial conditions. Then the autoregressive moving average method is used to build an original aerodynamic model, and the long short-term memory network is utilized to build a state prediction model. In condition of small variation of initial state, the original aerodynamic model remains valid; however in case of large variation of initial state, the state prediction model is transferred to the corresponding initial state, and then an aerodynamic model is built by using the autoregressive moving average method based on the predicted state parameters. The results show that the proposed method is suitable for accurate aerodynamic modeling of high-spinning projectile under the large variations of initial angular velocity and pitch angle. In comparison with the autoregressive moving average method based on direct CFD/RBD coupling simulations, the modeling efficiency of the proposed method is doubled.

Simulation Research on Ballistic Control of a New Tail Rudder Controlled Trajectory Correction Projectile

GUO Shouyi, WANG Liangming, FU Jian, LEI Xin

2024, 45(7):  2209-2217.  doi:10.12382/bgxb.2023.0178

Asbtract ( )   HTML ( )   PDF (3323KB) ( )  

Figures and Tables | References | Related Articles | Metrics

In order to enhance the response ability and trajectory correction effect of trajectory correction projectile’s control rudder and greatly reduce the aerodynamic turbulence influence of rudder on the projectile body in theory, a new type of two-dimensional trajectory correction projectile,in which the control rudder is placed behind the center of mass and can be highly matched with the tail of the projectile,is designed.A projectile body model is established, and a composite control strategy with the new optimized guidance scheme and proportional calculus control method as the main body is designed.The change law of state variable parameters in the uncontrolled and controlled states are analyzed, and the trajectory correction process based on the optimal values of parameters are simulated; Monte Carlo method is used to analyze the dispersion of impact points under the disturbance state. The simulated results show that the actual roll angle of tail rudder controlled projectile is basically consistent with the input command under this control strategy, and the change ranges of speed angle and direction angle in the whole process is only 2° and 7°, respectively. The control correction process based on the optimal values and the final impact point in the disturbance state also ensures that the projectile body can move smoothly and has better deviation correction ability, which further confirms that the designed new projectile model has high feasibility and reference value.

Simulation of Four-element Infrared Detection System Considering Missile Spinning

WANG Cheng, WANG Weiguo, MENG Chen, LI Qing, CHENG Yue, KONG Zihua

2024, 45(7):  2218-2227.  doi:10.12382/bgxb.2023.0170

Asbtract ( )   HTML ( )   PDF (5866KB) ( )  

Figures and Tables | References | Related Articles | Metrics

To precisely analyze the output signal of tracking circuit in a four-element infrared detection system and provide an accurate computational basis for the guidance and anti-jamming algorithms, this paper delves into its operational principle. Considering the missile spinning, the target image trajectory generated by combining the four-element infrared detection system with conical scanning is simulated. The information signals and target acquisition signals of four-element infrared detection system with and without interference are analyzed by taking a man-portable air defence missile as an example. Based on these findings, the signal simulations of pulse analog tracking and digital tracking circuits are accomplished, and a simulation software for the four-element infrared detection system is developed. Through simulation experiments, it is discovered that the direct simulation of output signal from four-element detection system without taking into account the missile spinning leads to the errors in the output signal simulation results of tracking circuit. When there’s only a target spot in the detector’s field-of-view, the target can be accurately captured and and its azimuth information is calculated from the detector output. However, when the interference spots present, the target acquisition signal output becomes abnormal. Both pulse analog and digital tracking circuits can compute the azimuth information of target, but the pulse analog tracking implementation is more intricate.

Numerical Calculation of Infrared Radiation Characteristics of Rocket Engine Exhaust Plume in Boost Phase

ZHANG Teng, NIU Qinglin, LIU Yunfeng, GAO Wenqiang, DONG Shikui

2024, 45(7):  2228-2239.  doi:10.12382/bgxb.2023.0546

Asbtract ( )   HTML ( )   PDF (5773KB) ( )  

Figures and Tables | References | Related Articles | Metrics

Rocket engine exhaust plume during the boost phase is a main object captured by space-based infrared early warning systems due to its significant infrared radiation features. A tripropellant solid rocket engine is taken as the research object. The calculation models of exhaust plume flow fields in continuous and rare regimes are established.The flight trajectory is determined considering the two-stage boost phase.The design parameters of engines are evaluated by the reverse optimization method, and the calculation of flow field is simplified by using an equivalent single nozzle method.The infrared radiation characteristics of rocket exhaust plume are predicted based on the statistical narrow band method and the line-of-sight approach.The results show that the afterburning effect makes the infrared radiation intensity of the plume increase by about 20 times and the in-band radiance increase by about 10 times. There exist two characteristic peaks in 2.7μm and 4.3μm bands in the infrared spectrum of exhaust plume. The spectral intensity of low-altitude exhaust plume is relatively high, and the integrated intensity within different spectral bands exhibits fluctuation patterns and trough region with the increase in altitude. The difference of the in-band radiances of exhaust plume in the boost phase is up to three orders of magnitude, especially in 4.3μm band.This work can provide a theoretical reference for the detection and recognition of rocket in the boost phase.

Analysis of Load Characteristics of Fuze during Penetrating a Multi-layer Target Based on the Matching Relation of Projectile and Target

LIU Bo, CHENG Xiangli, YANG He, ZHAO Hui, WU Xuexing, LIU Tao

2024, 45(7):  2240-2250.  doi:10.12382/bgxb.2023.0162

Asbtract ( )   HTML ( )   PDF (8678KB) ( )  

Figures and Tables | References | Related Articles | Metrics

To accurately analyze the load characteristics of fuze in the process of penetrating a multi-layer target, the characteristics of projectile-target forces under different working conditions of penetrating a multi-layer target are analyzed by cavity expansion theory and differential panel method. The propagation characteristics of projectile-target force in the projectile body and the frequency response characteristics of warhead-fuze system are analyzed based on the stress wave propagation equation. The two analyzed results show that the relationship between the fundamental frequency of projectile-target force determined by penetration speed and target spacing and the frequency response characteristics determined by the structure of warhead-fuze system determines the load characteristics of fuze. The finite element simulation and test results of warhead-fuze system further prove that the frequency response curve of fuze under the condition of high-speed penetration into multi-layer target is not fixedly concentrated at a certain frequency. When the natural frequency of a certain order of axial vibration of warhead-fuze system is close to the integral multiple of the fundamental frequency of projetile-target force, the frequency response curve of fuze load is obviously concentrated near the natural frequency of this order of axial vibration. The analysis of the influence of projectile-target parameters on the load characteristics of fuze in the process of penetrating a multi-layer target has important guiding significance for fuze initiation control algorithm and protection design.

Response Characteristics of Frequency-modulated Continuous Wave Fuze under Dense Sweep Jamming

ZHOU Wen, HAO Xinhong, YANG Jin, DUAN Lefan

2024, 45(7):  2251-2259.  doi:10.12382/bgxb.2023.0226

Asbtract ( )   HTML ( )   PDF (9198KB) ( )  

Figures and Tables | References | Related Articles | Metrics

As a typical suppressed jamming method, the dense sweep jamming poses a huge threat to frequency-modulated continuous wave (FMCW) fuze in the actual battlefield. Aiming at the problem that FMCW fuze is easy to fail under dense sweep jamming, the response process of FMCW fuze under dense sweep jamming is deduced on the basis of analyzing the working principle of FMCW fuze. Equivalent jamming effect after using zero time-domain interference sample is further analyzed, and the relevant simulation analysis and experimental verification are carried out. The simulated and experimental results show that the more similar the dense sweep jamming signal to the fuze signal, the larger the effective jamming proportion in the time-domain sample of beat frequency signal is. The interrupted-sampling and repeater jamming effect on the real target signal of FMCW fuze is produced after zeroing the interfered samples in time domain. Multiple false targets are generated on the envelope of distance dimension. The distribution of false targets is related to the equivalent duty cycle and jamming frequency after zeroing processing, which results in a significant increase in the explosion point dispersion of FMCW fuze.

Experimental Study on IPM for Buffering and Energy Absorption

ZHANG An, LI Changsheng, ZHANG He, MA Shaojie, YANG Benqiang

2024, 45(7):  2260-2269.  doi:10.12382/bgxb.2023.0422

Asbtract ( )   HTML ( )   PDF (9506KB) ( )  

Figures and Tables | References | Related Articles | Metrics

In order to ensure the reliability of hard target penetration fuze in the battlefield, an imitation bamboo type penetration fuze protection microstructure (IPM) is designed based on bionics principle. A dynamic model of fuze buffering system is derived based on the buffering and energy absorption mechanism. The Abaqus explicit dynamic finite element method is used to numerically simulate the mechanical properties of IPM and traditional straight edge structure under typical penetration conditions, and the buffering protection performances and compressive mechanisms of the two structures are compared and analyzed. Two structures made of metal materials (AlSi10Mg and GH4169) are prepared using the selective laser melting (SLM) 3D printing. The compressive strength and energy absorption characteristics of different cell geometries are investigated, and the reliability of the established finite element model is verified. The simulated results show that IPM has obvious negative Poisson's ratio effect and deformation integrity, which can eliminate stress concentration and attenuate the peak value of penetration overload by 131% on average. The 3D printing results show that GH4169 has better molding effect, complete features, and high structural strength, making it more suitable as a printing material for fine structures. The quasi-static compression results indicate that the initial yield stress of IPM is higher than that of traditional straight edge structure, showing a significant advantage in the platform area, and its total energy absorption is 72% higher than that of traditional straight edge structure. The results of this study provide a new strategy for the protection of hard target penetration fuzes.

Experimental and Numerical Research on Behind-plate Enhanced Lateral Effect of Reactive PELE

ZHANG Jiahao, GUO Mengmeng, ZHOU Sheng, YU Qingbo

2024, 45(7):  2270-2281.  doi:10.12382/bgxb.2023.0537

Asbtract ( )   HTML ( )   PDF (11581KB) ( )  

Figures and Tables | References | Related Articles | Metrics

To reveal the behind-plate enhanced lateral mechanism of reactive penetrator with enhanced lateral effect (PELE), the damage effect experiment of reactive PELE impacting steel plate is made to obtain the perforation damage of witness aluminum plate set behind the steel plate under the conditions of different front steel plate thicknesses. A two-step numerical simulation model of reactive PELE impact-induced deflagration reaction is developed based on the ignition growth model. The behind-plate enhanced lateral effect of reactive PELE impacting a steel target with a thickness of 6-20mm at 780m/s velocity is discussed by experiment and simulation. The damage effect of witness aluminum plate, filling reaction, wave interaction and jacket fragments dispersion are analyzed. The results show that the numerical simulation model can effectively simulate the deflagration reaction of reactive PELE impacting plate. The perforation dispersion on the witness plate significantly depends on the front steel plate thickness, the behind-plate enhanced lateral effect of the reactive PELE increases first and then decreases with the increase in the plate thickness, and the released energy of the reactive filling increases the maximum radial velocity of jacket fragments by more than 40%.

Complex Flow Field Characteristics inside Combustion Chamber During the Secondary Ignition Process of CTA

GUO Junting, YU Yonggang

2024, 45(7):  2282-2293.  doi:10.12382/bgxb.2023.0499

Asbtract ( )   HTML ( )   PDF (9402KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The flow field characteristics inside the combustion chamber during the secondary ignition process of a large caliber cased telescoped ammunition (CTA) is studied. A two-dimensional axisymmetric two-phase reacting flow model based on the Euler-Euler approach is used, combined with dynamic grid division theory and user-defined function technology, to numerically simulate the secondary ignition internal ballistic process of a 105mm CTA armor-piercing projectile. The results show that the main charge bed is ignited after the rupture of combustible guide tube, and the gas converges in the bottom area of the projectile, forming local eddies. The intensity of the eddies gradually increases, and the temperature at the center of the eddies gradually increases. Under the action of gas phase force, the main charge bed is compressed axially and radially to the bottom area of the projectile, and then is dispersed by a large amount of gas into the entire combustion chamber. It is found that the maximum breech pressure during the secondary ignition process is 560MPa, and the muzzle velocity reaches 1650m/s.

A Rapid and Near Analytic Planning Method for Gliding Trajectory under Time Constraints

WANG Peichen, YAN Xunliang, NAN Wenjiang, LI Xinguo

2024, 45(7):  2294-2305.  doi:10.12382/bgxb.2023.0343

Asbtract ( )   HTML ( )   PDF (4790KB) ( )  

Figures and Tables | References | Related Articles | Metrics

A rapid trajectory planning method based on drag acceleration-energy profile is proposed for the time controllable re-entry gliding. This method divides the gliding trajectory planning into longitudinal trajectory planning and lateral planning. In the longitudinal trajectory planning, a multi-segment smooth drag acceleration profile based on corridor boundary dual-parameter interpolation is designed, and a method for applying local path angle constraints at the terminal is provided. Then the analytical prediction expressions for time and range considering the influence of Earth rotation are derived, which improves the speed and accuracy of the prediction algorithm. The profile design is then completed by correcting the double profile parameters, while meeting the constraints of terminal energy, range, time, and local path angle. In the lateral planning, the dynamic/static heading angle error corridor method is used to avoid the no-fly zone and adjust the terminal heading, a target range and time correction strategy considering longitudinal and lateral motion coupling is further introduced, and a three-degrees-of-freedom gliding trajectory generation considering time constraints is completed. Finally, the effectiveness and multitasking applicability of the proposed method are verified by taking CAV-H re-entry gliding as an example for simulation. Compared with existing time analytical prediction methods, the proposed prediction method has significant computational efficiency and high computational accuracy. Compared with existing trajectory planning methods based on standard profiles, the proposed planning method has higher terminal accuracy, higher computational efficiency, and a larger time adjustable range, and can also achieve the rapid prediction of flight capability boundaries.

Scheduling Strategy of Aviation Information Network Service Function Chain Requirements

CAO Dai, ZHAN Siyu, HAO Xinsheng, GUAN Kai, FU Haotong

2024, 45(7):  2306-2317.  doi:10.12382/bgxb.2023.0258

Asbtract ( )   HTML ( )   PDF (4859KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The low resource utilization efficiency may be caused by service burst, dynamic change of topology structure and limited resources in aviation information network (AIN) scenario. A service function chain scheduling algorithm for network function virtualization is proposed for the efficient scheduling of service function chain requirement (SFCR). The algorithm is mapped according to the correlation between SFCR and the platform, thus improving the processing efficiency of server, effectively reducing the number of virtual network function (VNF) instantiations, and integrating the platform resources. In considering the impacts of delay and traffic, the network function instances are integrated and migrated to reduce the network energy consumption and improve the resource utilization. The simulated results show that the proposed approach has better optimization performance in terms of the number of running platfors, SFCR acceptance ratio, and the network resource consumption while guaranteeing the delay requirements, which is suitable for solving the SFCR scheduling problem in AIN scenarios.

An Adaptive Filtering-disturbance Observer-based State Estimation Algorithm for Large Ships

WANG Yong’an, LI Dongguang, WU Hao, LIU Yang

2024, 45(7):  2318-2328.  doi:10.12382/bgxb.2023.0588

Asbtract ( )   HTML ( )   PDF (3982KB) ( )  

Figures and Tables | References | Related Articles | Metrics

In order to meet the state estimation requirements of large ship targets such as aircraft carriers, an interactive multi-model strong compensating cubature Kalman filtering algorithm is proposed,which is formed by the fusion of nonlinear disturbance observer and strong tracking cubature Kalman filtering algorithm. The nonlinear disturbance observer is introduced to estimate the total amount of disturbance caused by external uncertainties and prove the stability of the observer, and then the estimated disturbance value is used to modify the process parameters of the strong tracking cubature Kalman filter in real time, which finally forms the interactive multi-model strong compensating cubature Kalman filtering algorithm and completes the relatively accurate estimation of target state. The results show that the proposed filtering algorithm can complete the more accurate estimation of target state, and has higher estimation accuracy in the estimation of target position and velocity compared with the variable-structure multi-model particle filtering algorithm, the variable-structure multi-model unscented Kalman filtering algorithm, and the interactive multi-model strong tracking cubature Kalman filtering algorithm.

Study of Water Surface Acoustic Waves Excited by Acoustic Radiation from Underwater Cylindrical Shells

ZHANG Shenghai, XU Jianqiu, LI Sheng

2024, 45(7):  2329-2340.  doi:10.12382/bgxb.2023.0191

Asbtract ( )   HTML ( )   PDF (9223KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The study of water surface acoustic waves excited by the acoustic radiation from underwater acoustic source is of great significance for cross-media underwater sound source detection in the air. In order to study the characteristics of water surface acoustic waves excited by the acoustic radiation from underwater acoustic source, the theoretical solution of water surface acoustic wave excited by the spherical acoustic wave radiation from underwater steady point source is derived based on underwater sound propagation theory, the pulsating spherical point source is used as an numerical analysis example to verify the model according to the finite element method, and the corresponding measurement experiments are designed and conducted to verify the horizontal attenuation law and the influence of sound source depth. Based on the acoustic-structure coupling finite element method, the influences of sound source parameters, such as sound source depth, and environmental parameters on the water surface acoustic wave induced by the acoustic radiation from underwater cylindrical shell are studied. The research results indicate that the amplitude of seawater surface wave excited by the cylindrical shell sound source in a semi-free field environment is much greater than that of other frequencies under certain vibration modes corresponding to the natural frequencies. The seabed and rough sea surface have an impact on the amplitude of water surface waves. Under the excitation of load, the amplitude of water surface waves excited by the sound radiation from underwater cylindrical shell in finite water depth is positively proportional to the depth of submergence within 3 times the radius of the cylindrical shell and beyond 20 times the radius, while other ranges are inversely proportional to the depth of submergence.

Dynamic Response of Vehicle Surface under the Action of Underwater Middle and Far Field Explosion Shock Waves

ZHANG Yong, XIAO Zhengming, DUAN Hao, WU Xing, LU Min, WANG Hao

2024, 45(7):  2341-2350.  doi:10.12382/bgxb.2023.0306

Asbtract ( )   HTML ( )   PDF (4891KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The dynamic response of underwater vehicle surface after an underwater explosion in the far field is predicted by the numerical algorithm based on arbitrary Euler-Lagrange method. In this paper, the impact of free surface on shock wave reflection is taken into consideration, the model mesh is refined using the explosion similarity theory, and the finite element software is used to solve the underwater explosion model. The timing and location of peak dynamic stress on the underwater vehicle surface subjected to the shock wave are determined, and the variations in dynamic response with equivalent, blast distance and water depth are studied. A dynamic stress equation for the underwater vehicle surface is obtained by a numerical fitting method, and the equation’s reliability is assessed through the coefficient of determination. It is observed that an increase in the equivalent results in a higher decay rate of dynamic stress in a fixed blast distance interval. Conversely, an increase in the blast distance leads to a reduced growth rate of dynamic stress in the same equivalent interval, while a decrease in water depth by 100 meters is associated with an approximate 20MPa increase in dynamic stress. The research outcomes offer valuable insights and serve as a reference for future investigations in safety protection and impact resistance assessments.

Large-scale Molecular Dynamics Simulation of Femtosecond Laser Pulse Ablation on TATB

WU Junying, LI Junjian, SHANG Yiping, YANG Lijun, CHEN Lang

2024, 45(7):  2351-2363.  doi:10.12382/bgxb.2023.0196

Asbtract ( )   HTML ( )   PDF (20567KB) ( )  

Figures and Tables | References | Related Articles | Metrics

A deeper understanding of the rapid chemical reaction mechanism and thermal response characteristics of explosivessubjected to femtosecond laser pulseablation is the basis for the development of femtosecond laser machining technology forexplosives. The large-scale reactive molecular dynamics simulations of 1,3,5-Triamino-2,4,6-trinitrobenzene (TATB)subjected to different femtosecond laser energiesare carried out based on ReaxFF/lg reaction force field. The non-linear absorption process of explosives to femtosecond laser pulse is considered, and the ablation mechanism, product evolution and thermal response of explosives are analyzed. The calculation results show that the ablation mechanisms of TATB are different underthe action ofdifferent intensity femtosecond lasers. When the laser intensity is 6.79×10¹⁷W/m², TATB is subjected toa plasma ablation, and the products are mainly small molecules. When the laser intensity is 3.39×10¹⁷W/m², TATB undergoes an incomplete reaction, and the products are mainly large molecules or clusters. When the laser intensity is 11.69×10¹⁷W/m², TATB is subjected to a photomechanical ablation, andthe explosives are removed in an intact original molecular structure. The higher the laser intensity is, the higher the temperature and particle velocity of ablation products are, and the more severe the thermal response around the ablation zone is, which could trigger the risk of ignition.

Study on Compressive Mechanical Properties of Graphene Aerogel

CAO Luqing, QIAO Yang, XIE Jing, CHEN Pengwan

2024, 45(7):  2364-2373.  doi:10.12382/bgxb.2023.0302

Asbtract ( )   HTML ( )   PDF (17160KB) ( )  

Figures and Tables | References | Related Articles | Metrics

In order to explore the potential application of graphene aerogel in the field of protection, different graphene aerogel samples are prepared by a freeze-drying method and controlled freezing temperature variable, and the uniaxial in-plane compressive mechanics experiments are carried out. The deformation pattern and failure mechanism are analyzed by using 3D digital image correlation (DIC) technology and scanning electron microscope (SEM).The results show that the graphene aerogel samples prepared by freeze-drying method have the characteristics of three-dimensional porous network structure, low density (<33.93mg/cm³) and high porosity(>98.5%), and have the characteristic microstructure affected by freezing temperature. The compressive stress-strain curves of graphene aerogel exhibit the typical three-stage characteristics of porous materials, and its mechanical properties are affected by the freezing temperature.The Young’s modulus of graphene aerogel obtained at -80℃ is increased by 160% compared with that at -19℃, and the energy absorption per unit volumeis increased by 67%. With the expansion of internal dense region during multiple cyclic loading-unloading of graphene aerogel samples, the absorption energy dominated by plastic energy tends to be stable and unchanged, and its states can be described by the exponential decay model. The different compression deformation forms of the transverse and longitudinal lamellas of graphene aerogels are developed into large-scale spring-like tight folding form, which made the graphene aerogels show resilience. This study provides a theoretical and practical basis for the application of graphene aerogels in the field of protection.

Experimental Study on the Effect of Liquid-filled Tube Structure on Shock Wave Attenuation

LIU Yu, LU Shufan, SUO Tao, HOU Bing, FAN Zhiqiang, LI Yuan

2024, 45(7):  2374-2382.  doi:10.12382/bgxb.2023.0260

Asbtract ( )   HTML ( )   PDF (4915KB) ( )  

Figures and Tables | References | Related Articles | Metrics

In recent years, the casualties caused by regional conflicts, terrorist attacks, and other explosive environments occurred frequently, causing widespread concern at home and abroad. Body injury caused by the explosion has become the main form of injury to soldiers in modern war. Here the attenuation effect of the liquid-filled tube structure for human body protection on the shock wave is mainly studied through shock tube test. Through the liquid-filled tube, the kinetic energy of shock wave is converted into the internal energy and kinetic energy of liquid in the tube, and the transfer and dissipation of the shock wave energy are realized with the release of liquid and its energy absorption. The results show that the protective structure can attenuate the peak overpressure by up to 35% and the specific impulse by 30%. The results could provide an important reference for human protection against blast shock waves.

Dynamic Response of Directional Blast Relief Container Structure for Civil Aircraft under Internal Explosive Loading

ZUO Mingshuo, XU Yuxin, LI Yongpeng, LI Xudong, GUO Delong, YANG Xiang

2024, 45(7):  2383-2392.  doi:10.12382/bgxb.2023.0327

Asbtract ( )   HTML ( )   PDF (8798KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The dynamic response of the directional blast relief container structure for civil aircraft under different TNT equivalent internal explosive impact is studied. A directional blast relief container for civil aircraft is designed to remove the explosive hazards in civil aircraft. Through the explosion test, the reliability of the blast relief container is verified, and the explosive critical inclusive equivalent of blast relief container is determined to be 42g. The dynamic response of blast relief container under different equivalent internal explosive loads is numerically simulated, and the motion process of a stopper and the mechanism of action of internal explosive load on the blast relief container are analyzed. The results show that the shear pin is shearing broke under the action of the explosion shock wave, and the stopper vibrates in shearing process; after shear pin is sheared, the stopper continuously accelerates, and about 7.5MPa quasi-static pressure is finally generated in the container. The stopper flys out at a uniform speed after it breaks through the fuselage bulkhead. The container relieves pressure, and a pressure gradient of about 0.38~0.85MPa is formed inward from the explosion vent. The TNT equivalent has a significant effect on the stopper flight speed. The flight speed of stopper increases and the rate of increase decreases with the increase in TNT equivalent. The study provides support for the design and application of explosion-proof containers for civil aircrafts.

Experimental Study on Damage of Reinforced Concrete Slabs under Natural Gas Explosion Load

QIAO Boyang, GU Gongtian, WANG Cheng, SONG Shixiang, GAO Yang

2024, 45(7):  2393-2403.  doi:10.12382/bgxb.2023.0538

Asbtract ( )   HTML ( )   PDF (14081KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The damage characteristics of reinforced concrete slabs under the natural gas explosion load are studied experimentally. A semi-underground gas explosion loading device with a volume of 9.8m³ is constructed for the experimental research on the damage of reinforced concrete slabs with the thicknesses of 80 mm and 100 mm and the strengths of C30, C40 and C50 subjected to methane explosion loading. The distribution characteristics of quasi-static pressure, out-of-plane displacement of concrete slabs, and equivalent strain in the explosion space were obtained. The results reveal that the quasi-static pressure exhibits oscillatory features under the combined effect of explosion pressure accumulation and crack venting of reinforced concrete slabs in an enclosed space. The distribution of equivalent strain coincides with the crack pattern, displaying a symmetrical Y shape, and the equivalent strain has the distinct bimodal and trimodal characteristics. The two reinforced concrete slabs with different thicknesses exhibit significantly different failure modes: the reinforcement structure of 80mm-thick reinforced concrete slab remains intact, and the concrete cracked and dispersed, with localized concrete shearing failure, whereas the fracture of 100mm-thick reinforced concrete slab occurred at the fixed joint, and the concrete slab is thrown as a whole, resulting in extensive shearing failure of the reinforced concrete composite.

Test and Numerical Research of Explosion Inside Partially Confined Tunnel Structure

CHEN Tainian, REN Huiqi, LI Suling, ZHANG Shanshan, ZHANG Chengjian, YUAN Ye

2024, 45(7):  2404-2413.  doi:10.12382/bgxb.2023.0480

Asbtract ( )   HTML ( )   PDF (8762KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The propagation and attenuation effect of blast wave in a proposed partially confined tunnel structure are investigated. A three-dimensional finite element model of the partially confined tunnel structure is developed to simulate the propagation of blast wave in the partially confined tunnel and quantify the blast loading vented from the internal space to the adjacent free field. The mechanism of vortex forming, venting effect and blast wave attenuation characteristics are revealed based on the numerical predictions. The significant improvement effect of a composite configuration consisting of T-joints, venting channel, and expansion chambers on the wave attenuation efficiency is revealed by using numerical predictions and theoretical predictions based on scaling laws, the venting effect of the proposed tunnel structure is quantified. and the blast overpressure distribution in the adjacent free-field is obtained. This work can provide technical support for the structural optimization design of the partially confined tunnel.

Compilation of Multiaxial Load Spectra for Fatigue Durability of Special Vehicle Based on Extreme Value Extrapolation

ZHENG Guofeng, YANG Siyu, CHEN Baixian, WEI Hanbing, ZHAO Shu’en

2024, 45(7):  2414-2425.  doi:10.12382/bgxb.2023.0431

Asbtract ( )   HTML ( )   PDF (7863KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The service load spectrum of off-road special vehicle is the key to the structural durability of the vehicle. A method for compiling the multiaxial load spectra for the fatigue durability of special vehicle based on extreme value extrapolation is proposed. Considering the phase relationship between the load channels during the extrapolation of multiaxial load spectra, the equivalent synthesis of multiaxial loads based on the critical plane damage parameter is studied. A multiaxial extrapolation model for the exceedance of extreme value being subjected to the generalized Pareto distribution is extablished. The load spectra are extrapolated using the equivalent synthesized load spectra, and the extrapolated variation is allocated to each load channel based on the synthesis coefficient to achieve the multiaxial load extrapolation considering the phase relationship. The multiaxial extrapolation is conducted by taking the six-directional force signal at the wheel center of special vehicles under typical working conditions as the objective. The aspects of the load spectra before and after extrapolation and the load spectra acquisited are all compared in terms of phase relationship, level crossing counting, rainflow counting and power spectral density. The results indicate that the multiaxial load compilation of special vehicle fatigue durability based on extreme value extrapolation can be used to effectively predict the multiaxial load spectra under the same typical working conditions.

Prediction of Service Life of Gyro Motor Bearing with Small Sample and Unequally Spaced Data

CAI Yao, WANG Jianqing, SI Yuhui, WANG Yuzhuo, GUO Wei, WU Zhan

2024, 45(7):  2426-2441.  doi:10.12382/bgxb.2023.0259

Asbtract ( )   HTML ( )   PDF (3022KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The bearing vibration signals are difficult to be collectedwhen the existing research results of bearing life prediction are directly applied to gyro motor bearings, and the modeling accuracy is low when the model uses small samples and unequally spaced data.The current signal of gyro motor is selected as the measurable signal, and an implementation standard is formulated to intercept the effective electric signal. Initializing root mean square (IRMS) and Renyi entropy are extracted as degradation features to describe the bearing life.The designed EMD-BBO-GM (1,1) model consists of interval change module, data decomposition module, model construction module and parameter optimization module, which can realize the function of bearing life prediction.A small and micro flexible gyro motoris selected for the bearing life prediction test. The results show that the predicted life of the model is equivalent to the actual life, the fitting accuracy is not less than 98%, and the prediction accuracy is not less than 95%. Compared with the standard GM(1,1) model, the prediction accuracy of this model is improved by 24.975%, and the contributions of interval change module, data decomposition module and parameter optimization module are 90.94%, 3.64% and 5.42%, respectively.

Multi-objective Joint Optimization of Resource Allocation and Task Scheduling for Accompanying Repair

LIU Shengyu, QI Xiaogang, LIU Lifang

2024, 45(7):  2442-2450.  doi:10.12382/bgxb.2023.0337

Asbtract ( )   HTML ( )   PDF (2697KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The modern war has a fast pace and covers a wide area, which puts forward higher requirements for the accompanying repair support mode. Integrate the process of resource allocation and task scheduling in a complex battlefield to give full play to the effectiveness of accompanying repair system has become the urgent demand and development direction of equipment maintenance support. Comprehensively considering the factors of multi-center, open, multi-repair state, time window, non-traversal, capacity limitation and so on, an idea of replenishing goods at any time is put forward for the first time, which combines the regional risk coefficient with the current cost of the maintenance teams. A more perfect mathematical model is established to maximize the maintenance benefit and minimize the risk cost. For the above problems, the multi-objective artificial bee colony (MOABC) algorithm is improved, a multi-objective artificial bee colony algorithm for memorizing multiple honey sources per bee is proposed. The proposed algorithm shows good performance in terms of solution quality and convergence speed. Then, aiming at the problem that a small number of extreme values affect the mean, the use of coverage rate indicator is improved and displayed in the way of frequency. Finally, the scientificness of the model and algorithm is verified through the simulation experiments and the evaluation of multiple indicators, and the joint optimization of resource allocation and task scheduling for accompanying repair is realized. The study shows that the above model and algorithm are able to provide the appropriate assistant decision-making for accompanying repair support.

Diagnosability Design Method Based on Fault-sensitive Learning and Integrated Learning

LÜ Jiapeng, SHI Xianjun, WANG Yuanxin

2024, 45(7):  2451-2462.  doi:10.12382/bgxb.2023.0413

Asbtract ( )   HTML ( )   PDF (2581KB) ( )  

Figures and Tables | References | Related Articles | Metrics

The diagnosability design of system can optimize the diagnostic scheme and improve the the degree of compatibility between diagnostic scheme and system, which is of great significance for the accurate detection or isolation of system faults. For this, a diagnosability design method based on fault-sensitive learning and integrated learning is proposed. The featuresfrom the collected signals of system test points in different states are extracted. Combined with the results of diagnosability evaluation of the system, a quantitative feature contribution algorithm is proposed to evaluate the contribution degree of different features in the signal to fault diagnosis. The improved D-S evidence theory algorithm is used to fuse the features of different signals, which can determine the fault sensitive feature set suitable for fault detection and isolation. The integrated learning method is used to strengthen the diagnostic effect of base classifier, and finally the diagnosis scheme of the current system is obtained. Simulation experiments show that the system diagnosis scheme designed by the proposed diagnosability design method can make a good diagnosis of system faults. Compared with no fault-sensitive learning, the error rate of fault diagnosis decreases from 5.33% to 2.66%. Compared with no integrated learning, the error rate of fault diagnosis decreases from 16.22% (mean value of base diagnostics) to 2.66%. In the comparison experiments with other diagnostic schemes, the fault diagnosis error rate of the proposed method is decreased by 3.34% compared to the average fault diagnosis error rateof other methods.