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    31 October 2022, Volume 43 Issue 10
    Electronic edition of this issue
    Electronic edition of this issue
    2022, 43(10):  0. 
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    Contents
    Contents
    2022, 43(10):  0. 
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    Paper
    Investigation of the Sensorless Motor Control Technology for Gun Autoloading
    QIAN Linfang, SUN Le, CHEN Guangsong, TONG Minghao, ZOU Quan
    2022, 43(10):  2417-2428.  doi:10.12382/bgxb.2022.0330
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    The modern automatic loading system for large caliber guns involves the collaborative control of multiple motors. The application of sensorless technology can significantly improve the reliability of driving systems. The rotor position identification of surface-mounted permanent-magnet synchronous motor at zero-/low-speeds is a difficult problem in sensorless control. To deal with it, an extended Kalman filter based on mechanical motion model is proposed to assist rotor position estimation. At the same time, the observer disturbance rejection technology is employed to eliminate the influence of disturbances such as model parameter uncertainty to rotor position identification, and to realize reliable start-stop control under zero/low speeds and heavy loads. The proposed method overcomes the limitation of the conventional rotor position estimation method based on the electrical model, greatly improves the load capacity of the sensorless technology at zero/low speeds, and realizes the performance comparable to that of the position sensor servo. This sensorless motor control technology is applied to the 155 mm gun loading system. Finally, the technology is verified by the operation simulation of the modular explosive loader and projectile loader as examples.
    Methods for Multi-Vehicle Cooperative Object Tracking
    GONG Shixiong, WANG Xu, KONG Guojie, GONG Jianwei
    2022, 43(10):  2429-2442.  doi:10.12382/bgxb.2021.0462
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    Multi-vehicle information fusion technology is an important way to improve the perception of the environment of ground unmanned systems. To address the problem of discontinuous and unstable object tracking in single-vehicle sensors caused by vision occlusion and blind spots, a result-level fusion system model for centralized multi-vehicle cooperative perception is proposed. The system model uses lidar as the vehicle perception sensor and stands on the D-S evidence theory to fuse the environment grid maps constructed by different vehicles at the main control terminal to obtain a global static environment map. Based on this environment model, a multi-vehicle cooperative object detection and tracking method is designed. First, a maximum value suppression method is used to resolve the fusion conflict of detected objects. Then, a cascaded dynamic object matching and tracking management method is designed to complete object prediction and tracking and send the results to vehicles. The test results of a real-vehicle system composed of two unmanned vehicles suggest that when the object is occluded, the proposed multi-vehicle cooperative object detection and tracking architecture can obtain more comprehensive environmental information of the object than a single-vehicle perception system. No tracking object is missed, and no jump occurs. The error between the tracker's output position state result and the detection result is small. The state of the tracked object can be accurately estimated, and the tracking trajectory remains continuous, thus effectively improving the field of vision of the single-vehicle environment.
    Vibration Reduction Control of Variable Stiffness Torsional Vibration Absorber Based on Real Vehicle Transmission SystemDynamic Characteristics
    GAO Pu, XIANG Changle, LIU Hui
    2022, 43(10):  2443-2450.  doi:10.12382/bgxb.2021.0475
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    The semi-control of the frequency adaptive magnetorheological elastomer(MRE) torsional vibration absorber is a key step to reduce torsional vibration in the powertrain system. In this paper, aiming at the powertrain system of a tracked vehicle, a dynamic system model with a MRE variable stiffness torsional vibration absorber is established. Based on the model, a control strategy combining transient look-up table and steady-state optimization is proposed to significantly reduce the deviation of the identified external excitation dominant frequency, allowing the absorber to be capable of quickly following the dominant external excitation frequency, thereby achieving semi-active control of the vibration absorber. The simulation and experimental results indicate that the proposed integrated control scheme can improve damping performance by 10%.
    Influence of the Control Oil Pressure on the Dynamic Characteristics of a Wet Multi-disc Clutch in the Disengaging Process
    ZHENG Liangjie, MA Biao, CHEN Man, YU Liang, ZHANG Cunzhen
    2022, 43(10):  2451-2459.  doi:10.12382/bgxb.2021.0506
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    During the disengaging process of a wet-multi clutch, the disengaging time, the friction torque and the friction pair gaps have a dramatic influence on the shifting quality of the vehicle. Thus, a comprehensive dynamic model is proposed to investigate the clutch disengaging process, which includes hydrodynamic lubrication, elastic-plastic contact between asperities, spline friction, and impact between piston and clutch hub. The influence of control oil pressure and its decreasing rate on the disengaging performance of a six friction-pair wet clutch are studied, and the non-uniformity coefficient is employed to characterize the disengaging uniformity. The results show that the decline in the pressure's decreasing rate not only prolongs the disengaging time, but also deteriorates the disengaging uniformity dramatically. Moreover, the decline in contact torque is retarded and the viscous torque is increased. However, the initial value of control oil pressure has a slight influence on the disengaging time and uniformity. The rise in control oil pressure increases the initial contact torque and its decreasing rate, and also decreases the viscous torque.
    Control Strategy for Vehicle-Based Dual-Motor Driving Moving Platform with High Inertia
    LI Fangjun, WANG Shengjie, LI Junfeng, WANG Li
    2022, 43(10):  2460-2472.  doi:10.12382/bgxb.2021.0501
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    A dual-motor driving strategy based on velocity curve planning is proposed for a vehicle-based high-inertia servo system with a contradiction between high dynamic response and stable operation. The dual-motor synchronous anti-backlash technology is adopted to compensate for the effects of backlash in the directional channel and pitch channel, smoothing out variations in driving torque and ensuring the stable operation of the system. The impact of the quick start-up procession and large acceleration which causes the low-frequency chattering problem is thus avoided through the propose planning of the speed curve of the servo system. Meanwhile, the speed planning command feedforward compensation improves the dynamic tracking accuracy of the servo system. Co-simulation and experimental results show that the dual-motor synchronous anti-backlash method can eliminate the influence of transmission clearance/backlash. The velocity curve planning approach with speed command feedforward compensation can effectively suppress the chattering problem of the high-inertia flexible structure and guarantee the system's response capacity.
    Characteristics of Intelligent Reversing Valve Based on High-speed on-off Valve
    ZHAO Huipeng, ZHOU Junjie, BAO Qianqian, MA Huichen
    2022, 43(10):  2473-2484.  doi:10.12382/bgxb.2021.0503
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    As traditional hydraulic valves have limited functions and flexibility in applications, a new intelligent reversing valve is designed and tested to expand the functions of hydraulic valves and simplify hydraulic system circuits. First, the theoretical basis and architecture of the intelligent valve with a high-speed on-off valve as the pilot valve is proposed. Then, a mathematical model is established for the intelligent directional valve, and a physical model of the valve is constructed using AMESim to simulate and study the dynamic and static characteristics of the pilot valve as well as the main valve. The results show that the response delay time of the pilot valve is approximately 5 ms, which is primarily affected by the driving voltage of the coil and the elastic coefficient of the spring. Finally, a PWM duty cycle displacement control method is proposed, and the feasibility of controlling the displacement of the main valve spool by controlling the duty cycle of the pilot valve's PWM signal is verified by simulation. The results show that when the PWM signal frequency is 50~100 Hz, the main valve has good linear control characteristics in the range of 0.2~0.8 duty cycle.
    Road Traversability Analysis of Unmanned Tracked Platform in Off-road Environment
    ZHOU Mengru, CHEN Huiyan, XIONG Guangming, GUAN Haijie, LIU Qingxiao
    2022, 43(10):  2485-2496.  doi:10.12382/bgxb.2021.0824
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    To deal with the problems of fuzzy road features and complex terrain in off-road environment, a road traversability analysis method for unmanned tracked platforms is proposed based on the fusion scheme of camera and lidar for sensing. Firstly, the semantic point cloud is obtained based on image semantic segmentation, and the passable area is roughly extracted. Then the three-dimensional point cloud is used to describe the ground geometric features, and road traversability is analyzed considering the trafficability constraints of the tracked platform. Finally, a three-dimensional traversable grid map containing road surface attributes and ground geometry information is generated. The definition of platform traversability in the proposed method reflects the strong coupling relationship between the platform and the environment. The experimental results show that the algorithm can stably establish the traversable map, provide good guidance for platform planning and control, and is conducive to the stable trafficability of the unmanned tracked platform in the complex off-road environment.
    Long-Range Rocket Simulation Training System Based on Hardware-in-the-Loop Simulation
    LI Siyu, HUANG Shaoluo, YAO Kai, WANG Jinsheng, LIU Huaqing, WU Weiyi
    2022, 43(10):  2497-2507.  doi:10.12382/bgxb.2021.0531
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    The problems existing in today's real equipment operation and maintenance training of complex weapon systems, such as high risk, complex operation, site limitation and harsh natural environment constrain the real equipment group training of relevant troops and military colleges,leanding to deficiencies in carrying out weapon equipment system group training, such as few training modes, great technical difficulty, poor training effect and so on. A new design method of complex weapon system simulation trainer based on hardware-in-the-loop simulation is proposed. Taking the long-range rocket system as the research object, a long-range rocket simulation training system based on hardware-in-the-loop simulation is developed, which provides a new training mode for our officers and soldiers to train modern complex weapon systems. A new game-set pair analysis method is proposed to evaluate the training effect. The results show that the simulation training system can effectively improve the professional quality of operation and maintenance of trainees, which is of great value for scientific evaluation of training effect.
    Engineering Model for Calculating Secondary Pressure Wave Overpressure Peak in Deep Water Explosion
    WANG Shushan, LIANG Ce, GAO Yuan, GUI Qiuyang, LIU Jianhu, SHENG Zhenxin
    2022, 43(10):  2508-2516.  doi:10.12382/bgxb.2021.0560
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    To study the influence of water depth on the propagation of underwater explosion (UNDEX) secondary pressure waves and the quantification of the overpressure peak is significant for engineering applications. A numerical simulation model for the deep-water explosion of a spherical TNT charge was established with AUTODYN, and the results were verified by the UNDEX test conducted in a pressure vessel. The calculation and test results are in good agreement and consistency. On this basis, 18 simulations for different conditions were performed to study the secondary pressure waves generated by the explostion of 30 g spherical TNT charge in the water depth range of 5 to 8 000 m, and 90 data sets were acquired. The analysis showed that: the overpressure peak of the secondary pressure wave of deep water explosion conforms to the Hopkinson law; the overpressure peak increases monotonously and continuously with the increase of water depth, and the increase rate decreases as water depth increases. With further data analysis and processing, an engineering model for calculating the overpressure peak of the secondary pressure wave of deep water explosion based on the Hopkinson law combined with water depth correction is obtained. The model has important engineering practicability and general scalability.
    Energy Release Characteristics of Kinetic Energy Rod with Reactive Material Headduring Water Entry and Penetration intoUnderwater Target
    SHAO Zhiyu, DONG Chaochao, WU Siyu, CAO Miaomiao, YANG Xiaotian
    2022, 43(10):  2517-2526.  doi:10.12382/bgxb.2021.0535
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    At present, both the impact effect of high-speed water-entry projectiles and reactive materials are hot research topics in underwater weapons and efficient damage technology. In order to verify the idea of combining the two highlights to cause efficient damage to underwater targets such as torpedo, mine, and submarine, water-entry impact experiments using a reactive material are carried out, and underwater target penetration experiments using kinetic energy rods (KE-rods) with the reactive material on its head are conducted. The experimental results demonstrate that when a single small-mass object made of the reactive material or a KE-rod with the reactive material on its head impacts water at the speed of about Mach 2, there is no observable exergonic reaction. Even if the reactive material releases energy before it hits water, the reaction would be impossible to continue due to rapid environmental pressure drop and rapid heat loss during penetration into water. After the KE-rod enters water and penetrates the shell of the underwater target, the reactive material produces a “detonation-like” reaction inside the target, which results in an enhanced damage effect. The experiment verifies the feasibility of an underwater-target-attack scheme in which reactive material is applied to the head of a KE-rod. The experimental results also provide a research idea for the development of weapon with efficient damage to underwater targets.
    Precision Detonation Control Problem of Smart Fuze in Complex Wide-Area Battlefield
    ZHANG He, YU Hang, DAI Keren, LIU Peng, YANG Yuxin, MA Xiang
    2022, 43(10):  2527-2533.  doi:10.12382/bgxb.2021.0530
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    To deal with the problem that the dynamic open-loop control design theory for traditional fuzes cannot meet the control needs of the development of the new generation of smart fuze, based on the analysis of space-time identification and process control as fuze detonation control, three scientific problems faced by the precise detonation control of smart fuze are proposed and deeply studied. At the same time, three types of controllers are constructed for smart fuze design, namely, environmentally adaptive detection controller, self-triggered time delay compensation state controller and virtual closed-loop detonation controller, and the design architecture of “three-element” cascade control of smart fuze is established. It can improve the precise detonation control accuracy of smart fuze in the complex wide-area battlefield, which lays a theoretical foundation for the further development of intelligent fuze.
    Guided Jamming Method for Pseudo-code Phase-modulated Pulse Doppler Fuze Based on Generative Adversarial Nets
    LI Jianfeng, YAN Xiaopeng, HAO Xinhong, YU Honghai
    2022, 43(10):  2534-2544.  doi:10.12382/bgxb.2021.0504
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    For the pseudo-code phase-modulated pulse Doppler fuzes, conventional guided jamming methods have low interference efficiency due to the difficulty of accurately estimating the compound modulation signal parameters in low SNR environments. A guided jamming method for the pseudo-code phase-modulated pulse Doppler fuze based on the generative adversarial nets (GAN) is presented to solve this problem, which can effectively interfere with the pseudo-code phase-modulated pulse Doppler fuze at low SNR. First, the intermediate frequency signal obtained by down-conversion of the pseudo-code phase-modulated pulse Doppler fuze is preprocessed. Then, the denoised information such as time-frequency distribution and phase is obtained. Second, the GAN model is used with the time-frequency distribution data to generate highly correlated data with the fuze intermediate frequency signal without having to estimate the fuze parameters in a low SNR environment. Finally, the fuze interference signal is reconstructed using the time-domain waveform generated by the inverse transformation of the newly generated data. Simulation and experiment results show that the guided jamming method based on GAN can achieve a better jamming effect on the pseudo-code phase-modulated pulse Doppler fuze in low SNR environments.
    Identification of Fuzzy Small-sample Terrain Targets Based on 1DC-CGAN and Wavelet Energy Features
    LI Xiaoxiong, ZHANG Shuning, ZHAO Huichang, CHEN Si
    2022, 43(10):  2545-2553.  doi:10.12382/bgxb.2021.0505
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    The carrier-free UWB fuze is featured by high distance resolution, strong anti-interference capability, and rich information about target structure. Also, it is not easily affected by light and climate conditions. When striking ground targets, different terrain will affect the blast height of the fuze, which in turn affects the damage effect. A terrain identification system based on carrier-free UWB fuze is thus proposed, which requires rich experimental data for accurate target identification. The acquisition of terrain echoes is time-consuming and costly, and the number of acquired echoes is often limited, which may affect the recognition accuracy. To expand the data set, an improved conditional generation adversarial network is proposed, replacing the fully connected layers of the generator and discriminator with one-dimensional convolution, adding batch normalization to achieve signal generation while reducing pattern collapse, and enhancing the sequence generation effect under small sample conditions. In addition, the wavelet energy features of the expanded echo signals are used as input features, and the particle swarm optimized BP (PSO-BP) neural network is used to achieve intelligent terrain classification. Experimental results show that the PSO-BP neural network trained on the expanded training set has improved the accuracy by more than 4% compared with training on the original training set.
    Rapid Estimation Method for Miss Distance of Rocket Projectile Based on Coupled Seeker-Projectile Model and AdjointGuidance System
    CUI Mengxi,HAO Hongxu, WANG Xinxing,MENG Liangfei,MAO Yutian,WAN Ke,LIU Yunzhen,ZHANG Yan
    2022, 43(10):  2554-2564.  doi:10.12382/bgxb.2021.0798
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    Rapidly estimating the miss distance of guidance system during the preliminary seeker design is an effective way to shorten rocket projectile development schedule. Based on the principles of rigid body kinematics and dynamics, the coupled mathematical model of a pitch-yaw two-frame stable platform seeker is constructed, which mainly considers the seeker-projectile coupling effect. Then, a rapid estimation method for the miss distance of guidance systems based on the adjoint theory is proposed. This method can quickly estimate the miss distance of a rocket projectile, and with the help of the coupled seeker model, real flight experimental data and simple guidance system parameters. the design parameters during the preliminary seeker development can be updated, thus reducing design iteration. The simulation results show that the coupled seeker model has high accuracy, and the miss distance can be rapidly estimated with the adjoint method, providing insights into the preliminary seeker and guidance system design.
    Anchor-Free Detection and Tracking System Design Based on Human-Computer Interaction
    WU Chao, WU Shaobin, LI Zirui, SUN Dong
    2022, 43(10):  2565-2575.  doi:10.12382/bgxb.2021.0682
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    To improve the accuracy and efficiency of object detection and tracking in the off-road environment, an anchor-free object detection and tracking system based on human-computer interaction is proposed. It consists of detection system, command system and object tracking system. For detection system, on the basis of point-based point cloud feature extraction framework, an anchor-free object detection network structure is designed. The command system can display information on real-time environmental situation and select targets interactively in the objects sequence output by the detection network. For tracking system, the appearance model in the objects sequence output by the detection system is used to match with that of the tracked target issued by the comand system to determine the target being tracked. Then the Kalman filter algorithm is adopted for objects motion estimation. The verification analysis is done based on real vehicle data in the off-road environment. The results show that the proposed system achieved an accuracy rate of over 91% without increasing the time taken by the algorithm, which can meet the requirements of autonomous vehicles in off-road scenarios.
    Anti-Interference Recognition Algorithm for Aerial Targets in the Complex Confrontation Environment on the Battlefield
    ZHAO Junmin, WEI Jiayi, WU Sijie, LI Xinguo, L Meibo
    2022, 43(10):  2576-2587.  doi:10.12382/bgxb.2021.0576
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    In the confrontatoin environment with complex background and infrared decoy flares, aerial target recognition by infrared imaging of fortification storming/HEAT missiles remains a challenge. For the problem of aerial target recognition, an anti-interference recognition algorithm with strong discriminative features is proposed, which integrates region generation, feature learning, classification and identification into the anti-interference algorithm to form an abstract recognition framework from the pixel level to region level and then to feature recognition step by step. Firstly, by simulating the typical battlefield environment, a large number of target feature libraries under different confrontation situations are generated, which serve as the basis of the algorithm research. Secondly, region proposals are formed by pixel similarity clustering, and “coarse granularity” location of regions is completed. Then the extracted region features are input into the feature selection module to learn the strong discriminative features. Finally, the selected features are input into the improved multi-classification support vector machines (SVM) for target classification and recognition, and the “finer granularity” locking of the target region is realized. Through the recognition mechanism of gradual refinement, aerial targets in the complex battlefield confrontation environment are recognized. The validation experiments show that the algorithm has an average recognition accuracy rate of 78.63% in the ballistic image datasets under different confrontation situations, which can effectively distinguish between targets and interference, and provide support for the development of algorithms in engineering applications.
    Head Shape Optimization and Water Entry Performance Analysis of Trans-medium Aircraft
    MA Wenchao, MENG Fanmin, MA Nuo, MENG Junhui, ZOU Ruping
    2022, 43(10):  2588-2597.  doi:10.12382/bgxb.2021.0538
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    The head shape of a trans-medium aircraft is one of the important factors affecting the kinematics in the trans-medium process. The common two-parameter cubic polynomial curve is used to obtain the shape curve dimensionless parameters of the trans-medium aircraft head shape. The Arbitrary Lagrangian-Eulerian method is adopted to complete the fluid-structure coupling modeling and performance analysis for trans-medium aircraft with different head shapes, and investigate the terminal velocity of different head shapes after entering the water and the maximum impact stress received during the water entry process. Taking the maximum terminal velocity and the minimum impact stress as the optimization goals, multi-objective optimization is carried out on the head shape of the trans-medium aircraft, and an optimal head shape is obtained. The results show that the optimal head shape of the trans-medium aircraft has significantly reduced speed attenuation and impact stress compared with the basic shape, the optimal head shape of the trans-medium aircraft effectively reduces the energy loss of the aircraft in the water-entry process. It can provide insights into the head shape design of the trans-medium aircraft.
    Path Planning for UUV Underwater Recovery based on Improved Composite Adaptive Genetic Algorithm
    ZHAO Pengcheng, SONG Baowei, MAO Zhaoyong, DING Wenjun
    2022, 43(10):  2598-2608.  doi:10.12382/bgxb.2021.0474
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    Mutations of traditional genetic algorithms generate new paths in a simple and random manner, which negatively influence the evolutionary performance of the algorithms and makes it easy for them to fall into the trap of local optimality. Moreover, genetic algorithms are usually used together with the grid method for path planning, and the optimal path obtained is not always the shortest path for UUV recovery path planning, and the UUV mobility performance might conflict with the optimal path.An improved genetic algorithm with UUV mobility constraints is thus proposed. The concept of environment complexity is proposed to analyze the specific value of mobility constraints, so that path planning can be adapted to UUV mobility, and the algorithm results can be more practical. The compound adaptive mutation strategy is proposed to control the adaptive evolution of the mutated individuals in the iterative process. When the population evolution stagnates after a certain number of iterations, the optimal individual is guided for a two-stage adaptive mutation so that the optimal path approaches the approximate global optimal solution, and the convergence rate of the algorithm is effectively improved. The algorithm comparison simulation results based on MATLAB software show that the optimal path generated by the improved compound adaptive genetic algorithm is smoother and shorter in length compared with the optimal path of genetic algorithm and adaptive genetic algorithm in generally complex water area and complex water area, which demonstrates that the improved compound adaptive genetic algorithm has better convergence performance and superiority seeking ability in path planning and is more feasible and superior.
    Design of a New Scheme for Gas Conduction of Thermal Missile Launching Based on Carbon Dioxide Ejection
    YANG Ying, JIANG Yi, LI Yulong, NIU Yusen, JIA Qiming
    2022, 43(10):  2609-2620.  doi:10.12382/bgxb.2021.0524
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    To deal with the problems of ablation, erection and retraction when using the deflector for exhaust conduction during thermal launching process of vehicular missiles, a new exhaust conduction scheme where carbon dioxide is ejected to impact gas jet so as to lower the temperatures of the launch vehicle and the missile is proposed. Taking the computational fluid dynamics(CFD) as the main research method, a three-dimensional steady model is established, and the characteristics of the cross flow field of gas jet and carbon dioxide are analyzed. The conclusions are drawn as follows: the temperatures of the launch vehicle and the missile decrease and then increase with the increase of the length of lower pipes; their temperatures decrease as the angle between the upper pipes and the launch vehicle wall decreases; the temperatures decrease with the decreasing height between the upper pipe orifices and the lower pipes. As the scheme remains meaningful when the distance between the nozzle exit and the ground is changed, this study provides a feasible new idea to design the exhaust conduction system for the thermal launching of vehicular missiles.
    Acoustic Characteristics of Gas-Liquid Multi-Cycle Pulsed Detonation Tube
    HUANG Xiaolong, LI Ning, KANG Yang, WENG Chunsheng
    2022, 43(10):  2621-2630.  doi:10.12382/bgxb.2021.0496
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    Acoustic distribution in the external flow field of a multi-cycle pulsed detonation tube is quite different from that in a single-cycle detonation flow. The detonation jet has an important influence on the acoustic characteristics in a subsequent cycle. The analysis of unique directivity and features in both time and frequency domains are presented in this paper. An acoustic experiment is performed on the detonation system for both single-cycle and multi-cycle using a 80mm detonation tube in free space. Result shows that the high frequency component in the detonation sound within the angle of 45° would be suppressed due to turbulence in the jet region. Severe attenuation of sound pressure peak in this region results in the formation of heart-shaped directivity patterns with a highest SPL at 45°. The relationship between jet diameter, angle and cut-off frequency is established, revealing a cut-off frequency of about 500 Hz within 30°. The detonation jet causes a gourd-shaped projection in the shockwave front near the axis, significantly reducing propagation time. The acoustic efficiency of the multi-cycle detonation is about 12%, greatly higher than that of a conventional jet.
    Axial Force and Hole Quality in SiC/GFRP Laminated Composite Armor by Rotary Ultrasonic Machining for Hole Drilling
    DONG Xianglong, ZHENG Lei, WEI Wendong, L Dongming, ZHU Zhuozhi, XU Subai, QIN Peng
    2022, 43(10):  2631-2639.  doi:10.12382/bgxb.2021.0533
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    Due to its high strength, high hardness, high toughness and high viscosity, SiC/GFRP laminated composite armor after molding has considerable difficulty in hole drilling. Damages such as laminat interface failure, ceramic chipping, and fiber tearing tend to occur during hole drilling. The novel thin-walled diamond core drill prepared by the hybrid process of sintering and brazing was used. Combined with rotary ultrasonic vibration technology assisting with hole machining, the kinematic model of a single abrasive particle was established, the core drill and the workpiece were separated by contact periodically during ultrasonic vibration drilling, and the discontinuous cutting characteristic is conducive to reducing the axial force. The hole-drilling experiments on SiC/GFRP laminated composite armor were conducted. The change law of the axial force and the hole quality in conventional machining and ultrasonic vibration-assisted machining were analyzed. The results showed that: compared with conventional sleeve grinding, the axial force in the case of ultrasonic vibration-assisted sleeve grinding was significantly reduced, with a maximum decrease of 31.8%; the bonding at the laminate interface during ultrasonic machining was tight and no serious ceramic breaking occurred; defects featuring irregular bulges and large bulge height in holes by conventional machining were effectively avoided, and the maximum reduction of bulge height was 61.03%, which significantly improved the surface quality of the holes and reduced the degree of hole damage. The results provide theoretical reference for the continuous hole machining in SiC/GFRP laminated composite armor with high efficiency and low damage.
    Effects of Structural Parameters of Intermeshing Co-Rotating Twin Screw Extruders on Key Mixing Parameters
    LI Cheng, XUE Xiaojun, HU Jianshu, YIN Yanhua
    2022, 43(10):  2640-2648.  doi:10.12382/bgxb.2021.0495
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    The influence of twin-screw structural parameters on key mixing parameters has been investigated through the analysis of how eight structural parameters of an intermeshing co-rotating twin-screw extruder affect six key mixing parameters (peak temperature,peak pressure, viscosity dissipation, mixing index, average residence time, and torque results). Orthogonal experiments are chosen as the experimental scheme for the twin-screw extruder. Prediction models for the influence of different structural parameters on the six mixing parameters are established. The co-rotating twin-screw extrusion software Ludovic is used to derive models for calculation, and the calculation results are analyzed using Statistical Product and Service Solutions (SPSS). The results show that: (1) The peak temperature increases with the increase of the lead of the reverse threaded element and decreases with the increase of the lead 1 of the forward threaded element. (2) Compared with a reverse kneading block, a reverse thread element can build up more pressure. In actual engineering, a reverse screw element or reverse kneading block is typically placed in front of the screw exhaust section to create a vacuum. (3)With the addition of reverse thread elements and reverse kneading block elements to the screw, the screw's filling degree and viscosity dissipation will increase. (4) The mixing index increases as the lead of the forward kneading block and the lead of the reverse screw element increase. (5)The reverse screw element and kneading block can extend the residence time of the material in the twin screw. (6) Highly significant factors that influence the torque are forward threaded element lead 2 and reverse threaded element lead.
    Wireless Cooperative Transmission in Joint Tactical Communication Network
    HU Jinsuo, ZHOU Guoyin, ZHANG Ying, SHAO Qihong, FENG Xiaorong
    2022, 43(10):  2649-2656.  doi:10.12382/bgxb.2021.0493
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    The wireless simultaneous interpreting technology based on physical layer is investigated to address the risk of communication disruption caused by topological changes of tactical communication networks. First, MIMO cooperation and multi-hop relay cooperation models are established based on typical scenarios. Second, the channel capacity and signal-to-noise ratio of the model are analyzed. To verify the findings, an experiment is designed, and the results under different transceiver configurations, codings, and hops are compared. Finally, the structures of two kinds of cooperative transceivers are described and their hardware implementation complexity analyzed. Theoretical analysis and simulation experiments have proved the effectiveness and feasibility of the wireless simultaneous interpreting technology in reducing the risk of network outages.
    Boundary Layer Transition Flight Measurement and Implementation
    OU Chao, LONG Yaosong, YANG Qingtao, XIAO Hanshan, ZHOU Yu, YANG Kai
    2022, 43(10):  2657-2667.  doi:10.12382/bgxb.2021.0523
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    For the needs of hypersonic boundary layer transition flight test and research, through integrating the variable thickness thin wall temperature test and heat flow identification method, where thin wall temperature measurement is used to identify the surface heat flux, then aircraft surface transition position can be measured. Considering the requirements of surface aerodynamic heating and the vibration environment during the high speed flight of the aircraft, the integrated module of the measuring structure and the aircraft structure is designed to improve the overall load resistance of the measuring structure. The thermal-vibration test system is to test the thermal measuring components under the ground simulation condition of flight state, and the safety and reliability of the measuring structure are verified. The results of ground thermal-vibration and flight tests show that the transition measuring structure can withstand the aerodynamic heating and vibration environment under flight conditions, respond quickly to and accurately reflect the changes of heat flow in the aerodynamic heating environment, and accurately capture the hypersonic boundary layer transition phenomenon under flight conditions. The measured data can provide calibration data for the prediction and calculation model of hypersonic transition.
    Combinatorial Optimization Methods for Determining the Pre-storage Location and Pre-setting the Distribution of EquipmentMaintenance Materials
    CAO Junhai, ZHANG Chuang, LI Yantong, GUO Yiming, GUO Qingyi
    2022, 43(10):  2668-2678.  doi:10.12382/bgxb.2021.0498
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    The pre-storage and pre-setting of maintenance materials are important for forming combat effectiveness rapidly in the early stages of a war. Methods for determining the pre-storage location and preparing distribution of maintenance materials for army equipment are thus proposed. To obtain the globally optimal solutions, the location of pre-storage facilities and the pre-setting of materials are integrated into a combinatorial scheduling problem. A MILP model is proposed to minimize the weighted sum of the fixed costs of pre-storage facilities, transportation costs, and tardiness penalties. An efficient logic-based Benders decomposition algorithm is developed to solve the problem. Numerical experiments based on 160 randomly generated instances show the superiority of the proposed algorithm in obtaining optimal solutions. At the same time, the comparison between the combinatorial and traditional sequential methods verify that the former can generate solutions with higher quality. The model and algorithms proposed may provide a basis for the decision-making process regarding the pre-storage and pre-setting of maintenance materials for military equipment during wartime.
    Mechanism of Amplifying Distortion at Low Frequencies in Vibration Meadurement
    YANG Weiyuan, HU Junqi
    2022, 43(10):  2679-2686.  doi:10.12382/bgxb.2021.0508
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    The reason for the amplifying distortion of vibration power spectrum at low frequencies is analyzed. It is validated through Matlab simulation that the combination of low-frequency signals and a specific analysis method are the cause. The physical reason for low frequencies is analyzed, and it is proved through tests that the bad contacts of the circuit, overranged sensors, poor connection of detected structures or sensors, and unidirectional pulse of special structures may cause distortion. The simulation results fit well with the experimental ones.
    Comprehensive Review
    Review on Target Detection of Image Homing Ammunition
    YANG Chuandong, QIAN Lizhi, XUE Song, CHEN Dong, LING Chong
    2022, 43(10):  2687-2704.  doi:10.12382/bgxb.2021.0610
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    The onboard image target detection method is the key technology to realize the autonomous attack on the target by the “fire-and-forget” image homing ammunition. At present, the image homing of ammunition is faced with some problems, such as bad imaging environment, rapid change of targets' characteristics, and strict requirements for algorithm volume and speed. Firstly, the target detection methods based on deep learning are divided into methods based on anchor box, methods without anchor box and methods based on transformer, and the main technical progress of various methods is reviewed. Then, the key technologies in onboard image target detection model deployment, such as lightweight feature extraction network, enhancement of feature map for prediction, non-maximum suppression post-processing algorithm, sample equalization in training, and model compression, are studied. Finally, the performances of the typical detection algorithms on ImageNet, COCO and datasets for onboard image are compared, and the possible development in the future is looked into.