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    30 June 2022, Volume 43 Issue 6
    Electronic edition of this issue
    Electronic edition of this issue
    2022, 43(6):  0. 
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    Contents
    Contents
    2022, 43(6):  0. 
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    Paper
    Uncertainty Analysis of Ammunition Ramming Process Based on Probability Density Evolution Method
    WANG Mingming, QIAN Linfang, CHEN Guangsong, LIU Taisu
    2022, 43(6):  1215-1224.  doi:10.12382/bgxb.2021.0298
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    A uncertainty analysis method for ammunition ramming process based on probability density evolution theory is proposed to analyze the influence of uncertain parameters in ammunition ramming process on the consistency of ammunition ramming. The ADAMS dynamic model of ramming process is established. The generalized probability density evolution equation of ramming process solved by finite difference method based on Lax-Wendroff scheme is derived,in which the relationship between state space and probability space is established by the joint probability density function of projectile state variable and random parameters of ammunition ramming process.The simulated displacement curve of ADAMS model is basically consistent with the experimental data,which verifies the accuracy of the proposed model. Compared with the Monte Carlo method,the response probability density function calculated by the proposed method is acceptable.The influence of parameter uncertainty on the projectile response under different working conditions is analyzed,and the mean square error of response is calculated.The results show that the fluctuation range of projectile response expands with the increase in ammunition ramming angle.
    Surface Temperature and Its Gradient of Gun Barrel Bore
    LIU Pengke, YANG Diao, XU Yaofeng, NING Bianfang, WANG Jun, LIU Huan
    2022, 43(6):  1225-1232.  doi:10.12382/bgxb.2021.0296
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    The high temperature combustion gas of gunpowders results in the decreased surface material strength of barrel decrease,the phase change and the melting during gun firing. This will accelerate the erosion,wear and cracking of barrel surface. Therefore,it is important to study the surface temperature and its gradientof barrel bore to explain the damage mechanism of barrel. A thermal-structure coupling dynamic model is established for 155 mm gun barrel,and the influence law of rifling edge chamfering and in-bore chromium plating on the surface temperature of barrel is simulated and analyzed. he simulated results are compared by the thickness of heat affected layer on the inner surface of barrel. The results show that the surface temperature of barrel decreases rapidly along the radial direction,forming a great temperature gradient. The temperature of the inner surface reaches 1 500 ℃,and the temperature at 190 μm exceeds 727 ℃,reaching the phase transition temperature. There is obvious heat accumulation at the edge of rifling,which makes the temperature at this point more than 300 ℃ higher than that on the surface of rifling. And the temperature at the edge of rifling decreases about 100 ℃ after chamfering. And the chrome plating in the bore can reduce the temperature of the substrate by about 400 ℃.
    Modeling and Simulation of Self-stable Gun Line Control Using Interference Rate Compesation
    LI Wei, HAN Chongwei, LIU Aifeng, REN Haibo, HU Xin, JIANG Junfeng
    2022, 43(6):  1233-1245.  doi:10.12382/bgxb.2021.0295
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    A self-stabilizing control method for gun line based on interference rate compensation in geodetic coordinates is proposed to achieve the high precision stability and tracking control of gun under the conditions of moving base and high firing angle. The proposed method can used to effectively restrain the influence of self-propelled artillery attitude disturbance on the gun line pointing. According to the motion law of stable gun line on a moving base,a mounting mode of interference rate measuring gyro is designed,and the decoupling compensation values of the azimuth and pitching interference rate in geodetic coordinates are derived. On the basis of the traditional anti-aircraft gun servo principle,the interference rate feed-forward compensation is applied to realize the self-stabilization and control decoupling of gun line. Since the gun stability is only related to two degrees of freedom of turret rotation and gun pitching,both of which have eccentricity moment and other factors. The Newton-Euler approach is used to establish a dynamic model of moving carrier,gun and turret. The nonlinear stiffness and backlash of transmission mechanism are considered combined with the executive motor model and classical closed-loop control. The control strategy is simulated in the two cases of ignoring elasticity and considering elasticity,respectively,under the conditions of three-axis compound swaying with the heading,pitching,rolling amplitudes of 7° and period of 2 s of vehicle body. The simulated results show that the proposed stability control method with interference rate compensation is used to achieve the stable firing angle of more than 60°,the stability control error of less than 0.5 mrad and the sinusoidal stability tracking control error of less than 2.8 mrad,and the control decoupling of pitching an azimuth is realized.
    Research on Velocity Nonlinear Suppression Technology of Gun Pitching Electro-hydraulic Servo System
    DAI Pu, PAN Jun, MA Qing, LIU Miao
    2022, 43(6):  1246-1254.  doi:10.12382/bgxb.2021.0357
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    Due to its special structure,the electro-hydraulic servo system of gun pitch has serious velocity nonlinearity,which not only leads to different equal amplitude rotation time in different angle intervals,but also seriously affects the dynamic tracking performance of the system. Based on the analysis of the principle of pitching electro-hydraulic servo system,the mathematical model of pitching servo system motion is established,the nonlinear motion law of pitching electro-hydraulic servo system is obtained,and the suppression method of velocity nonlinearity of pitching electro-hydraulic servo system is proposed. By introducing nonlinear observation and nonlinear compensation links,the velocity nonlinearity of pitching electro-hydraulic system is well suppressed,The control characteristics of the system are improved. The simulation and prototype experimental results show that this method has good control effect,can suppress the nonlinearity from the speed master output by the position loop to the rotation speed master of the pitching body, and realize the linearization from the speed master output by the position loop to the rotation speed master of the pitching body,so as to significantly improve the rotation and dynamic tracking performance of the artillery pitching electro-hydraulic servo system.
    Water-entry Trajectory of Truncated Cone-shaped Projectile
    SHAO Zhiyu, WU Siyu, CAO Miaomiao, FENG Shunshan
    2022, 43(6):  1255-1265.  doi:10.12382/bgxb.2021.0301
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    The attitude deflection and trajectory bending of truncated cone-shaped projectile will occur during water-entry process. The process is analyzed theoretically and the attitude deflection equation is obtained. AUTODYN software is used to simulate the water-entry process of truncated cone-shaped projectile. Based on the simulation results, an empirical formula describing trajectory of centroid is proposed, and its accuracy is verified by experiments.The vertical water entry test of projectile is designed, and the impact velocity and motion process of projectile are recorded by high speed camera. The experimental results show that the attitude deflection equation obtained from theoretical analysis is reliable, and the numerical simulation and empirical formula of centroid trajectory based on numerical simulation is reliable.
    Interior Ballistics of Independent Water-surface Launching Canister
    ZENG Peigao, JIANG Yi, YANG Lina
    2022, 43(6):  1266-1276.  doi:10.12382/bgxb.2021.0318
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    The Realizable k-ε turbulence model,the mixture multiphase model and the dynamic layering mesh update method are used to investigate the interior ballistics of a new independent water-surface launching canister,and analyze its influencing factors by modeling the relative motion between the missile and the canister. The interior ballistics and the internal flow characteristics of canister launcher on water-surface and ground are analyzed and compared numerically,and the influence of the canister emerging velocity on the interior ballistics is investigated. Results show that the launchers on water-surface and ground have the similar flow characteristics in the gaps and in the pressures in the low pressure chambers. The exit velocity of the missile on water-surface is faster than that on ground,the maximum missile load on water-surface is 20% less than that on ground,and the launch time for the water-surface launching is 14% less than that on ground.The flow results show that the gas does not directly interact with the water surface,therefore the phase change energy dissipation does not happen.The emerging velocity changes the ejection velocity increment by affecting the force of water on the canister.The nonlinear effect of the emerging velocity on the increment of ejection velocity can be ignored because the buoyancy variation is far less than the gas force,so the exit velocity of missile is a linear superposition of the emerging velocity and the increment of ejection velocity.
    Dynamics Characteristics and Influencing Factors of Multistage Canister Gas Ejection of Rockets
    PAN Xiao, JIANG Yi, WANG Boman, REN Yebo
    2022, 43(6):  1277-1287.  doi:10.12382/bgxb.2021.0316
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    The dynamic characteristics of a multistage canister gas ejection structure and the influencing factors during ejection are analyzed to improve the ejection performance of rockets and to study the safety of gas ejection structure. The structural composition,topological relationship and excitation load of the rocket multistage canister ejection system are analyzed,and a finite element model of the ejection system are established for simulation analysis. Through experiments,it is verified that the simulation accuracy of finite element model meets the simulation requirements. The influences of the gap of cylinder section,the thrust eccentricity and the launch angle on the safety of multistage canister gas ejection structure are analyzed based on the finite element model. It's found that the launch angle is the main influencing factor that affects the ejection safety,and the gap between the cylinder sections and the thrust eccentricity have also effect on the ejection safety. he influencing factors lead to the ejection deflection of rocket,the interaction force between the canister sections and the increase in the maximum lateral displacement. When the gap between the canister sections is increased to 0.3 mm or the launch angle is deflected to 3°,a greater threat will be posed to ejection safety.
    Shock Initiation Characteristics of DNAN-based Aluminized Melt-cast Explosive
    LI Shurui, DUAN Zhuoping, BAI Zhiling, ZHANG Xu, HUANG Fenglei
    2022, 43(6):  1288-1294.  doi:10.12382/bgxb.2021.0354
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    To investigate the effect of explosive particle size on the shock initiation characteristics of insensitive aluminized melt-cast explosives,a one-dimensional Lagrange measuring system with the multiple electromagnetic particle velocity gauge is established for sapphire flyer impact initiation. The particle velocity profiles for the shock initiation and detonation growth processes of an DNAN-based aluminized melt-cast explosive are obtained with different impact velocities. The effects of flyer impact velocity and explosive particle size on the shock initiation and detonation growth are analyzed,and both the shock Hugoniot relation and the parameters of equation of state for unreacted explosive are determined for the aluminized melt-cast explosive. The measured particle velocity profiles are typically in a shape of hump,and the post-shock particle velocity increases obviously and goes after the leading wavefront. The shock initiation process is characterized by accelerated reaction. The post-shock particle velocity increases more rapidly and the shock initiation grows faster in the case of higher loading pressure and smaller particle size. It indicates that the mesoscopic structure greatly affects the shock initiation and detonation growth of aluminized melt-cast explosives.
    Influence of Aperture of MOFs Material on the In-situ Synthesis of Copper Azide-carbon Composite Primary Explosives
    QIN Jian, CHI Dianpeng, YANG Li, HAN Jimin, TONG Wenchao
    2022, 43(6):  1295-1303.  doi:10.12382/bgxb.2021.0355
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    In-situ synthesis is a key technology to solve the problem of tiny explosive charges. In order to explore the influence of pore size of metal-organic frameworks on the in-situ synthesis of copper azide,three kinds of copper-containing metal-organic frameworks with different pore sizes were prepared by ordinary solution method. The azide reaction is carried out after high-temperature carbonization,and finally a copper azide-carbon composite primary explosive is obtained. The products at each stage are characterized using nitrogen adsorption and desorption,SEM,PXRD, DSC and other characterization methods. The results indicate that the pore size affect the azide degree of copper in the framework,and the larger the pore size is,the more sufficient the azide reaction will be.
    Effect of Equivalent Ratio on Two-phase Rotating Detonation Wave of Kerosene-air
    FENG Wenkang, ZHENG Quan, WANG Xiaowei, DONG Xiaolin, WENG Chunsheng, XIAO Qiang, MENG Haolong
    2022, 43(6):  1304-1315.  doi:10.12382/bgxb.2021.0352
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    In order to study the effect of equivalent ratio on two-phase rotating detonation wave of kerosene/air,the two-dimensional numerical simulations of liquid kerosene at normal temperature as fuel and high total temperature air as oxidant are carried out based on the Eulerian-Lagrange method. The two-phase rotating detonation flow fields under different equivalent ratios are calculated by controlling the kerosene inflow,and the effect of equivalent ratio on flow field structure,propagation characteristics and thrust performance is analyzed. The results show that the height of detonation front decreases with the increase in the equivalent ratio in the range of a certain equivalent ratio. The velocity deficit generally increases with the increase in the equivalent ratio when the equivalent ratio is greater than 0.6,with a range of 7.1%~17.2%. Fuel loss occurs when the equivalent ratio is greater than 0.8,and increases approximately linearly with the increase in the equivalent ratio,which is up to 51% when the equivalent ratio is 2.0. With the increase in the equivalent ratio,the specific impulse decreases,and the specific thrust increases first and then decreases,and reaches the maximum when the equivalent ratio is 1.5,the variation ranges of specific impulse and specific thrust are 1 154.3~3 912.4 s and 1 226.8~ 1 521.8 N·s/kg,respectively.
    Aerodynamic Characteristics of Close-coupled Canard Missile
    L Dailong, CHEN Shaosong, XU Yihang, QIU Jiawei
    2022, 43(6):  1316-1325.  doi:10.12382/bgxb.2021.0329
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    Because the normal force of the canard surface of missile will decrease at high angle of attack, resulting in reduced maneuverability, in order to obtain high maneuverability and high maneuverability, an anti stabilizer is installed in front of the canard, resulting in favorable interference between the anti stabilizer and the canard rudder. A computational study for a fixed-canard dual-spin rocket projectile is described. On the basis of verifying the reliability of the numerical method,the aerodynamic characteristics of three states,i.e.,no canards,reverse-spinning canards correction fuse and non-spinning canards correction fuse,at supersonic speed are studied. The influence of canards correction fuse on the lateral force of overall projectile and its components is analyzed emphatically. The results show that the drag coefficient and normal force coefficient of the overall projectile increase,and the lateral force coefficient of projectile increases dramatically with the angle of attack after the installation of canards correction fuse.The lateral force produced by the projectile body is affected by the canards,which is the main component of the overall projectile's lateral force,and the canards correction fuse itself is the least. After the installation of the canards correction fuse,the interaction between wake vortex of the canards and the body vortex is the main reason for the increase in lateral force produced by the body and the tail fins.
    Parameter Dimensionality Reduction and Optimal Design of Aircraft Airfoil Based on Deep Autoencoder Neural Network
    WU Zeliang, YE Jianchuan, WANG Jiang, JIN Ren
    2022, 43(6):  1326-1336.  doi:10.12382/bgxb.2021.0346
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    The traditional parametric description methods of aircraft airfoil have lead to low optimization efficiency and heavy calculation workload because of large amount of variables in optimization design.A neural network model based on deep autoencoder(DAE) is proposed to solve the dimensionality reduction of description parameters in airfoil optimization design. The physical meaning of each parameter output by the model is analyzed,the dimensionality reduction effect of the model on airfoil description parameters is compared with that of the proper orthogonal decomposition(POD) method. Under the given design objectives and constraints,an optimization design framework based on surrogate model and genetic algorithm is used for RAE2822 airfoil optimization in the transonic flow.The airfoil optimization design effects of the proposed model,Class Shape Function Transformation(CST) method and POD method are compared,which proves that the proposed method with neural network based on DAE has higher optimization efficiency,and it performs obviously better than both CST and POD methods in drag reduction design of RAE2822 in transonic flow.
    Motion Characteristics of the Small Caliber Anti-aircraft Gun Correction Projectile Subjected to a Pulse Action
    YANG Zhiwei, WANG Liangming, CHEN Jianwei, YIN Yongyang
    2022, 43(6):  1337-1345.  doi:10.12382/bgxb.2021.0302
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    A complex attack of angle equation and a complex deflection angle equation are established to study the motion characteristics of small caliber anti-aircraft gun correction projectile subjected to the pulse action. The pulse action process is divided into two processes: direct force action of pulse and aerodynamic action caused by pulse. The analytical solutions of the complex angle of attack equation and the complex deflection angle equation of the two processes are deduced,respectively,to obtain the expression of the average deflection angle,and the generation mechanism of the velocity deflection angle is analyzed.The correctness of the analytical solutions is verified by comparing the simulated result with the numerical solution.The results show that the pulse thruster should be installed in front of the center of mass of fin-stabilized project, so as to maximize the change of velocity direction produced by a single pulse thruster;the aerodynamic action caused by the pulse has a much greater impact on the velocity direction of the projectile than the direct force action of the pulse.The pulse action lead to a speed increase in the direction perpendicular to the thrust force of the pulse thruster.
    Design of Attitude Control System for Flexible Inflatable Spacecraft
    ZHAO Chunming, JIAO Shenghai, WANG Xiaofei, YAO Yuemin, HUANG Chaodong
    2022, 43(6):  1346-1354.  doi:10.12382/bgxb.2021.0593
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    An attitude control method based on the theory of active disturbance rejection control is proposed to accurately control the attitude of flexible inflatable spacecraft. A rigid-flexible coupling dynamic model is established, and a coupling attitude control system is designed using the linear active disturbance rejection controller,attitude maneuver path planning algorithm,pulse-width pulse-frequency (PWPF) modulator and low-pass filter. The control system can be used to control the attitude and suppress the elastic vibration simultaneously. The numerical simulations are conducted to verify the effectiveness of the proposed system. In contrast to the traditional PID control,the simulated results show that the attitude control system for flexible inflatable spacecraft designed by the proposed attitude control method can adapt to large-angle attitude maneuver and effectively suppress the flexible vibration of inflatable capsule,improve the attitude accuracy of flexible spacecraft and avoid frequent on-off of the engine to save fuel.
    Test and Simulation of SiC Ceramic/UHMWPE Fiber Composite Structure Against 12.7mm Armor Piercing Incendiary Projectile
    LI Yongpeng, XU Yuxin, ZHANG Jian, HUA Peixin, ZHAO Xiaoxu
    2022, 43(6):  1355-1364.  doi:10.12382/bgxb.2021.0604
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    The composite structure composed of SiC ceramic board and ultra-high molecular weight polyethylene (UHMWPE) fiberboard is studied. In order to understand the influence of component thickness on the penetration resistance of the anti-ballistic body, the test of 12.7 mm armor-piercing incendiary projectile penetrating into the composite structure was made to obtain the penetration effect at different impact velocities. A finite element model of a projectile penetrating into the composite structure is established, and the reliability of the model is verified by tests. The proposed finite element model is used to simulate the composite structure of 12.7 mm armor piercing incendiary projectile penetrating into different thickness components, and the failure mechanism and anti-ballistic performance of composite structure subjected to projectile penetration are analyzed. The results show that the proposed finite element model can be used to reliably calculate the effect of 12.7 mm armor piercing incendiary projectile penetrating into the composite structure. The ballistic performance of the composite structure increases linearly with the increase in the component thickness, and the influence of SiC ceramics on the ballistic performance is greater than that of UHMWPE fiberboard. With the increase in the thickness ratio of SiC ceramic and UHMWPE fiberboard, the ballistic performance of composite structure first increases and then decreases. When the thickness ratio is between 0.2 and 0.4, the ballistic performance of composite structure is the best.
    Two-step Imaging of Bistatic SAR with Curvilinear Trajectory Based on Space-Variant Separation
    XU Xiyi, TAN Gewei, LI Biao
    2022, 43(6):  1365-1375.  doi:10.12382/bgxb.2021.0398
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    To solve the severe two-dimensional space-variant issue of different configurations of bistatic SAR with curvilinear trajectory,a two-step processing method based on space-variant separation is proposed. First,space-invariant phase compensation is performed on the echo in the range frequency domain-azimuth time domain to conduct range migration correction and Deramp processing,and achieve coarse focusing. The residual phase is the space-variant part related to the position of the point target after the first step of focusing. Then the Keystone transformation is introduced to the range direction,and the least square fitting of Doppler parameters and azimuth resampling in the azimuth direction are derived,compensating the space-variant phase error and completing precise focusing. Simulation results show that the proposed slanting distance equivalent model based on space-variable separation has high accuracy. The two-step algorithm effectively relieves two-dimensional space variation and strong coupling of the curvilinear bistatic SAR,improving the imaging performance of edge points,realizing a large imaging area,and demonstrating a wide range of scenarios.
    Influence of Weight Parameters on the Effective Range of Supercavitation Projectile
    GU Jianxiao, DANG Jianjun, HUANG Chuang, LI Daijin, LIU Fuqiang
    2022, 43(6):  1376-1386.  doi:10.12382/bgxb.2021.0319
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    To obtain the influence of weight parameters on the effective range of supercavitation projectile,a coupling numerical method of supercavitation flow and rigid body motion is established based on the VOF multiphase flow model and the space motion equations of rigid body. The proposed method is validated by the experimental data in literature Ref\[23\]. The underwater ballistic characteristics of supercavitation projectile were studied,and the influence of typical weight parameters,such as centroid position and mass,on the effective range of the projectile were obtained. The results show that the underwater trajectory of supercavitation projectile has a stable tail-slap phenomenon,and the wavelength and amplitude of tail-slap keep approximately constant. Increasing the distance of centroid position away from the cavitator can effectively increase the underwater range of supercavitation projectile. The range of supercavitation projectile is increased by 14% when the centroid distance is increased by 9%. The mass of supercavitation projectile can be increased to significantly increase the underwater range. The range of supercavitation projectile increases by 70% when its mass is increased by 150%.
    Path Planning of Deep-sea Landing Vehicle Based on Ant Colony Algorithm
    GUO Wei, WU Kai, ZHOU Yue, SUN Hongming, XU Gaofei, GAO Sen
    2022, 43(6):  1387-1394.  doi:10.12382/bgxb.2021.0342
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    A three-dimensional subsea global path planning algorithm suitable for landing vehicles is proposed for “path optimization” of undersea operation of,deep-sea landing vehicles. The grid equal division method is used to establish a 3D submarine environment abstract model for the operating area of landing vehicle. An energy consumption model of navigation movment of landing vehicle is established by dynamically analyzing the navigation process of landing vehicle and testing the speed and work efficiency of driving motor. Local and global pheromone update-based energy consumption-distance path planning algorithm based on ant colony optimization is adopted,and the energy consumption and distance are introduced into heuristic and evaluation functions. The experimental results show that the proposed algorithm can effectively balance the mileage and energy consumption of path planning by reasonably selecting the weight parameters of the evaluation function. It has good convergence speed and global search ability,and can meet the needs of subsea scientific research operation of deep-sea landing vehicle.
    Experimental Study on the Energy-absorbing Structure of Broadside Defense Cabin Subjected to Underwater Contact Explosion
    CHAI Songlin, HOU Hailiang, JIN Jian, LI Dian, LI Yongqing
    2022, 43(6):  1395-1406.  doi:10.12382/bgxb.2021.0328
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    The deformation and energy-absorbing characteristics of broadside defense cabins with different structures are compared to study the feasibility of the application of sandwich structure in the broadside defense cabin. Four structural forms of broadside defense cabin cabins were designed,and 300 g TNT underwater contact explosion damage tests were carried out,respectively. Through comparative analysis of the deformation and destruction of the inner bulkheads of four broadside defense cabins,it is concluded that the boundary must have a strong support structure for a structure that uses the large flexible deformation of inner wall of the tank to absorb energy,and it is difficult to exert the tensile energy absorption effect of film when the support is insufficient.For the sandwich structure of the energy-absorbing tank that utilizes the integral deformation and energy absorption of inner wall of tank,the arc-shaped plate and inner wall of energy-absorbing tank,the arc-shaped plate provides strong support for the inner wall of tank and can deform and absorb energy together with the inner wall of tank,thus ffectively improving the protection ability of broadside defense cabin. a foam aluminum layer is added between the arc-shaped plates,failing to achieve a better protection effect.The arc-shaped plate is moved forward to the sandwich structure of the liquid tank, and the setting of arc-shaped plate causes the energy in the water to be not fully dissipated to the entire tank,and the accumulation of energy causes more serious damage to the internal tank.
    3D Path Planning of Underactuated AUV Based on Complex Constraints
    ZHANG Jiawen, FANG Haolin, LI Jiawang
    2022, 43(6):  1407-1414.  doi:10.12382/bgxb.2021.0340
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    An improved ant colony algorithm based on third-order B-spline curve fitting is proposed for the 3-D path planning and collision avoidance of underactuated AUV in complex waters,in which the underactuated motion characteristics and vehicle constraints are considered. An underwater space environment is modeled by simulating the real sea environment complexity. For the short service life issue of the underactuated AUV steering wheel,which is caused by large angle of turn and zigzagging route coming from the global path planned by original ant colony algorithm,a global path is planned by setting a vertical safety zone and redesigning the fitness function and evaluation function based on the factors of short path length and high path smoothness.TAn optimized path is fitted by using B-spline curve. And the continuous and safe path trajectory satisfies the velocity vector constraint of goal point. The simulated results show that the planned path is feasible on the precondition of guaranteeing the high convergence speed and global search capability.
    Optimization Method of Unmanned Swarm Defensive Combat Scheme Based on Intelligent Algorithm
    MA Ye, FAN Wenhui, CHANG Tianqing
    2022, 43(6):  1415-1425.  doi:10.12382/bgxb.2021.0339
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    Troop deployment and task allocation are important processes of unmanned swarm defense operations, it's very important to make effective use of the limited forces in the swarm and wield the highest operational efficiency to improve the battle victory rate of unmanned swarm. At the same time, efficient combat task allocation can coordinate the consistency of swarm and better complete combat tasks. Aiming at the key combat plan in unmanned swarm defense operations, the optimization of troop deployment and coordinated task allocation in unmanned swarm defense operations is studied. A multi-agent-based unmanned swarm defensive combat model is built to quantify the key parameters required for the deployment of unmanned swarm forces, the model plans the combat area and troops, and designs the objective function. An adaptive genetic algorithm is proposed to solve the deployment problem of unmanned swarms. The proposed algorithm could dynamically adjust the objective function,crossover rate and mutation rate according to the real-time operating conditions,ensuring the inheritance of individuals with higher fitness values and avoiding the local optimization of the algorithm. A defensive operation is simulated to verify the deployment effectiveness of unmanned swarm forces. The improved deep reinforcement learning algorithm based on deep Q network is proposed to find a solution to the task allocationfor the deployed unmanned swarms. The proposed algorithm could adjust the Q value through self-adaption to avoid non-convergence caused by the algorithm's overestimation and find the optimal solution.The experimental results of defensive operations show that the proposed unmanned swarm force deployment and coordinated task allocation method could effectively improve the success rate of defensive operations,and realize the autonomous coordination and intelligent confrontation of unmanned swarms.
    Kinematic Reliability Analysis for Redundant Robots Based on Envelope Method
    DING Li, GU Jiahui, ZHOU Jinyu, KANG Shaopeng, CHEN Yifei, LI Ziyi
    2022, 43(6):  1426-1434.  doi:10.12382/bgxb.2021.0308
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    A kinematic reliability analysis method based on envelope method is proposed for the research on the kinematic reliability of end-effector of 7 degree-of-freedom redundant robots subjected to the link length,link offset and joint angle. The deduced kinematic error functions of the robot are linearized by the first-order Taylor formula. A failure model of position and pose of end-effector is obtained by the probabilistic method. The time-varying kinematic reliability problem can be transformed into time-invariant kinematic reliability problem by the envelope method. The point of the greatest failure probability in the trajectory is found,and the internal relationship between the maximum failure point and the end point is analyzed by introducing covariance matrix. The kinematic reliability of the robot is calculated by multidimensional normal integration. Finally,a simulation case is conducted to verify the proposed method. The results show that the results obtained by the envelope method agree with those obtained by the Monte Carlo method,but the efficiency of the solution is greatly improved. Compared with the equivalent extremum method,the envelope method has higher accuracy and better robustness.
    Analysis of Structural Performance of Composite Duct Supporting Structure Based on Approximate Model
    LI Bin, XIE Xin, TANG Wenyong, TAO Jiangping, SUN Yiqiang, ZHAHG Hui
    2022, 43(6):  1435-1446.  doi:10.12382/bgxb.2021.0300
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    The ensemble neural network approximation model method with variable weight coefficient is used to replace the structural finite element calculation in order to analyze the structural performance of the composite duct supporting structure of an air cushion vehicle for efficient structural design. Several neural network models are establishedaccording to the sensitivity of the ply design parameters to the structural performance,and the predicted response values are obtained from the weight coefficients and the output of each model. Based on the designability of composite materials,the influence of material parameters on the performance of the supporting structure is analyzed microcosmically and macroscosmically level by using the optimized Latin hypercube design method. The results show that: the approximate model for the composite material has a high accuracy;and the fiber elastic modulus and matrix shear modulus have significant impact on the mechanical properties of the composite material of the supporting structure. The increase in fiber volume fraction can improve the stiffness and stability of the structure when the properties of component materials are fixed. The influences of fiber volume fraction and ply angles on the structural failure are different under different stress states,so special consideration should be taken in the design.The proposed method provides a theoretical basis for the structural performance analysis and the integrated design of composite material duct supporting structure.
    Reliability Analysis of Aircraft Fuel Closed-loop Control System Based on GO Methodology and Markov Process
    LI Jingkui, LIN Wenjie, JIANG Xiuhong, LU Yuze
    2022, 43(6):  1447-1455.  doi:10.12382/bgxb.2021.0288
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    Aircraft fuel control system is the energy control center of engine. The aircraft fuel control system has an important influence on the flight performance of aircraft. An engine electronic controller is used to control the thrust of engine by adjusting the fuel flow,while the bypass valve is reversed to open to form a closed-loop feedback control system. To enhance the reliability calculation accuracy of the system with closed-loop link,a system reliability calculation method is proposed based on GO (Goal-oriented) methodology. A GO model is established according to the principle diagram of aircraft fuel control system. The state transition matrix of closed-loop link is obtained by using Markov state transition process theory. The steady state probability formula of the closed-loop link is derived for the reliability calculation of a certain aircraft fuel control system. The results show that the proposed method considers the influence of closed-loop feedback signals on the system reliability while not changing the modeling rules of GO methodology,which can more truly reflect the reliability of the aircraft fuel closed-loop control system.
    Design and Performance of Precision Symmetric Two-stage Micro-drive Amplification System
    YANG Manzhi,JING Gang,GUO Wei,ZHANG Chuanwei,WU Hongzhang,WEI Kaiyang, LI Linyue,L Zhenyang,GUI Haochen,ZHANG Xiaodong
    2022, 43(6):  1456-1465.  doi:10.12382/bgxb.2021.0351
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    In order to obtain a fretting platform with high motion precision,no parasitic motion,large amplification ratio and adjustable,based on the guiding principle,driving principle and mechanism lever principle of straight round flexure hinge,a two-stage amplification mechanism with symmetric driving and adjustable amplification ratio (design amplification ratio is 1∶5) is designed. The design scheme of precision two-stage micro-drive amplification system driven by piezoelectric actuator is proposed.The guiding principle and additional force balance principle of the driving performance of the micro mechanism were analyzed,and the two-stage amplification ratio of the two-stage micro-drive amplification mechanism was calculated theoretically. The driving performance of the system micro actuator is analyzed by experimental method,and its driving equation is analyzed. The strength,modal and motion performance of the system are analyzed by finite element method. The analysis results show that the strength and modal performance of the system meet the requirements,and the system has high motion precision (The maximum absolute error and relative error are 6.27 μm and 8.36% respectively in the motion stroke).The two-stage micro-drive amplification system with precision symmetric driving designed in this paper has the advantages of high motion precision,excellent safety performance,large amplification ratio and adjustable.