At present,the radio fuzes are facing a severe information-based jamming environment.To ensure that radio fuzes can stably exert their damage effectiveness on the battlefield,the anti-information-based jamming-related technologies have become a research hotspot in the field of anti-jamming for radio fuzes.Based on the working process of fuze jammer,which first intercepts and then retransmits jamming signals,it is focused on the design of low intercepting point-like beam of radio fuze.A design principle of low intercepting point-like beam for radio fuzes based on the frequency diverse array (FDA)-multiple-input multiple-output (MIMO) is proposed on the basis of the unique S-shaped curved array pattern of FDA-MIMO technology.The impact of the frequency offset setting of array elements on beam synthesis is studied after analyzing the beam function of FDA-MIMO.A larger beam amplitude is achieved within a small neighborhood with Δr as radius in the vicinity of the peak point by setting a peak point and a power drop point within a relatively close distance Δr,while the beam amplitude drops rapidly in other ranges.Then,the frequency offsets of each array element are calculated by using the beam function,and the design method of the low intercepting point-like beam with the frequency offset setting formula of array elements as the core is obtained.Simulationed reults show that,under the guidance of the proposed low intercepting point-like beam design method,the FDA-MIMO beam has a range dimension half-power beam width of 1 meter and an angular dimension half-power beam width of 9 degrees.Its beam convergence performance and LPI performance are significantly better than those of other classic frequency offset setting methods.The proposed design method provides theoretical support for the low intercepting point-like beam design of radio fuzes based on FDA-MIMO,which can improve the LPI performance of radio fuzes and better exert their battlefield damage effectiveness.

In order to study the explosion driving characteristics of shell fragments driven by cylindrical charge with cavity and reveal the mechanism of the influence of shaped charge structure on the initial velocity of shell fragments,the explosion driving process and initial velocity distribution of shell fragments under different cavity cone angles are studied through the numerical simulation.The initial velocity distribution function of shell fragment along the axial direction is fitted by analyzing the rarefaction wave propagation path,velocity loss coefficient and fragment acceleration process.The relative error between the calculated and simulated results is less than 15%.The results show that the earlier generation of rarefaction wave and the decrease in cross-section ratio of mass of charge to shell are the main factors contributing to the decrease in the initial velocity of fragments.The initial velocity of the fragments near the non-detonation end decreases with the decrease in the cone angle of cavity and the increase in the cone top height of cavity.The rarefaction wave reflected from the non-detonation end is an approximately planar wave and is at a certain angle to the cavity surface.The instant when rarefaction wave reaches shell is linearly and positively correlated with the axial position of the shell.The cross-section ratio of mass of charge to shell has a quadratic function relationship with k,where k is the ratio of the distance from the cross section to the non-initiating end to the height of cavity cone top.The velocity loss coefficient decays exponentially with the decrease in k.The research can provide a useful reference for the overall structural design,material selection and structural optimization of anti-armour and anti-personnel composite warheads and the deformable fragment warhead with cavity charge structure.

Hydrodynamic retarder plays a key role in the driving assist braking system,and the main challenge it faces is the problem of rapid response and accurate prediction of braking torque.To achieve rapid onset,a pressure tank is used to accelerate oil-filling for a heavy equipment,but the changes in tank pressure and wheel speed during the oil-filling process will dynamically affect the filling flow rate and braking torque.Therefore,this paper constructs a prediction model for the oil-filling process of the hydraulic retarded braking system considering the pressure tank,realizes the two-way dynamic update of the boundary conditions of flow parameters at the inlet and outlet of wheel cavity,and deeply explores the hydrodynamic-hydraulic coupling relationship between the wheel cavity system and the charging and discharging control system.The simulated and experimental results show that the prediction error of the proposed model for peak torque is 15.61%,and the response time error is 15.04%,which verifies that the proposed model is capable of effectively exploring the braking characteristics of hydraulic retarder under the condition of fuel supply from the pressure tank for actual vehicle.The influence of the pressure tank characteristics on the braking torque characteristics at a given inertia and initial speed is further analyzed,and the regulation mechanism of the pressure tank parameters on the dynamic process of oil-filling is clarified.

The traditional dung beetle intelligent optimization algorithm has good global search capability,but its performance is affected by the initialization parameter settings,which can lead to problems suchas blind spots in the local search,and non-communication between populations,etc.To address the problem of search blind spots in identifying the threats or no-fly areas for 3D trajectory planning of UAVs,a multi-strategy improved dung beetle optimization algorithm is proposed to improve the global trajectory planning capability.The initialization parameters,dung beetle ball-rolling behavior,small dung beetle foraging behavior and dung beetle stealing behavior are improved by using a novel chaotic mapping,a novel Cauchy-Lorenz wandering strategy,an improved triangular wandering strategy,and a novel Cauchy's inverse cumulative distribution function wandering strategy,respectively.The dung beetles of each population are crossed by using an improved longitudinal and transversal crossover strategy,and the ability of the UAV to identify the threat areas and the global trajectory planning is enhanced by the improvement of the multi-strategy.The results show the superiority of theimproved dung beetle algorithm in UAV trajectory planning.The total cost of the improved optimization algorithm is only 57.88% of the cost of the traditional dung beetle intelligent optimization algorithm,which is reduced by 42.12%.Compared with the total costs of the sand cat swarm algorithm,the particle swarm algorithm,the hippopotamus algorithm,and the gray wolf algorithm,the total cost of the proposed algorithm is reduced by 38.37%,38.80%,44.17% and 41.80%,respectively.

To improve the precision of impact loads when applying loads via light-initiated explosives,the spray deposition distribution patterns of light-initiated explosives are studied using a specially designed spray coating system.The relationships among spray deposition efficiency,width,areal density distribution,and spraying distance at different spraying distances (10cm,15cm,and 20cm) are obtained.An equation describing the spray deposition distribution pattern of light-initiated explosives is obtained through fitting.The uniform spray coating on flat surfaces and the synchronous detonation verification are is experimentally studied based on the spray distribution model and spray superposition principle.The research results indicate that the spray distribution follows a pattern of being higher in the middle and lower on both sides.As the spraying distance increases,the effective spray width gradually widens,while the deposition efficiency decreases.The uniform spray coating on flat surfaces can be achieved by rationally planning the spray coating path.The maximum deviation between the measured areal density and the design value of the light-initiated explosive coating is 3%.The maximum asynchronous initiation time of light-initiated explosives is 8.52μs.This research lays a foundation for the future application of precise loading techniques for light-initiated explosives.

The impulse radio ultra-wideband radar (IR-UWBR) has insufficient target recognition capability under the conditions of small sample size and complex detection scenes.Regarding the above-mentioned issue,this paper proposes a moving target recognition method based on range-Doppler map and adaptive feature selection network (RDM-AFSN).An IR-UWBR Doppler information extraction model is established based on the analysis of the law of IR-UWBR receiving the echo signals in the slow time dimension.At the same time,the characteristics of the moving target range-Doppler map,which has large differences in image spatial features due to complex background information and many target types,are deeply analyzed,and a RDM-AFSN target recognition model based on coordinate soft threshold denoising module and spatial adaptive down-sampling layer is constructed.Experimental results demonstrate that the proposed model effectively improves the classification capability of moving targets under small sample sizes and achieves good recognition results for similar targets in different scenarios.Compared to the convolutional-recurrent deep network and image coding deep network commonly used for ground target recognition,the proposed RDM-AFSN improves recognition accuracy by 3.64% and 7.53%,respectively.

To reduce the computational complexity of the gridless matrix reconstruction method for L-shaped coprime array and improve the success probability of angle matching under low signal-to-noise ratio,a low complexity gridless two-dimensional direction-of-arrival (DOA) estimation method for L-shaped coprime array is proposed.The proposed method utilizes the conjugate augmentation method to realize the array virtual extension of x-axis and z-axis coprime arrays by solving the cross-correlation functions between array elements.According to the idea of matrix-form atomic norm,the array interpolation is realized by the decoupled atomic norm minimization method; The estimated value of the angle between axes is obtained by the root multiple signal classification (MUSIC) method.According to the spatial consistency between the signal subspace and the array manifold matrix,the angle matching is realized by solving the cost function.To further reduce the computational complexity,the matrix-form atomic norm is combined with the unitary transformation,and the unitary array interpolation is realized by the real-valued decoupled atomic norm minimization method.The results show that,on the one hand,the proposed method improves the accuracy of DOA estimation,reduces the computational complexity,and enhances the probability of successful angle matching.On the other hand,the computational complexity is further reduced by sacrificing part of the DOA estimation accuracy and array degrees of freedom.The feasibility and advantages of the proposed method are verified through simulation experiments.

To investigate the ballistic characteristics of a quasi-elliptical cross-section projectile penetrating into finite-thick concrete target,the tests are made on the normal and oblique penetrations of quasi-elliptical cross-section projectiles into the concrete targets with different thicknesses.The variation trends of the longitudinal acceleration and trajectory deflection angle of projectile during different penetrating stages are analyzed through the numerical simulation using the finite element method-smooth particle Galerkin (FEM-SPG) algorithm.The effects of impact velocity,target plate thickness,oblique angle,rolling angle and angle of attack on the trajectory deflection are discussed.The research results show that the trajectory deflects toward the flatter surface and the deflection mainly occurs in the tunnel stage and the plugging stage when a quasi-elliptical cross-section projectile penetrates into a target plate with finite thickness.As the thickness of the target plate increases,the trajectory deflection angle increases.The deflection caused at the cratering stage is only 1.4% of the final deflection angle in numerical simulation.There is a critical impact speed,which makes the deflection angle of the normal penetration trajectory decrease with the increase of the penetration speed above this target impact speed,while below this critical value,an inverse relationship is observed.Furthermore,the critical speed demonstrates non-monotonic dependence on target thickness,exhibiting an initial increase followed by progressive reduction until stabilization occurs.The trajectory changes from downward deflection to upward deflection with the increase in the angle of attack (-6°-6°) when the projectile penetrates into a target at the same oblique angle.The trajectory has excellent stability within the range of 0°-30° oblique angle at 2° angle of attack.The attitude stability of the projectile generally weakens first and then increases with the increase of the rolling angle on Oxz plane.When the rolling angle is less than 150°,the projectile shows a negative angle of attack after it ends interacting with the target.

In order to study the performance of explosives after the impact detonation of different shaped charges on targets in water,three kinds of shaped charge structures,i.e.,explosively formed projectile (EFP),jetting projectile charge (JPC) and shaped charge jet(JET),are selected for underwater penetration and underwater impact detonation tests.The measured velocities of different shaped charge penetrators before entering water,before hitting a target and after penetrating into a target,the penetration effect on the arc target plate and the impact detonation effect on B explosive behind the target are obtained through the tests.The impact detonation mechanism of different shaped charges in water and the variation law of impact detonation coefficient k at different water medium lengths are compared and analyzed.The results show that the impact detonation performances of EFP,JET and JPC after impacting a target in water decrease nonlinearly with the increase in the length of water medium,and the performance of JPC is better than those of JET and EFP.The critical impact detonation coefficient of explosive B is 18.22mm³/s² after EFP,JET and JPC penetrate the metal target plate with a thickness of 2cm and a length of 0-100cm water medium and a water medium with a length ranging from 0 to 100cm.

To solve the problems existing in the modular design of gun equipment,such as the insufficient overall of common modules and the lack of adaptability evaluation,a design method of modular firepower system for multi-platform universal artillery is proposed.Taking a large-caliber artillery as the research object,A modular design process based on launch dynamics is established using the parametric modeling and multi-level optimization algorithm,and the corresponding fitness evaluation method and tool are developed.The fitness evaluation tool is used to evaluate the universal design of firepower system on a 4 types of chassis.The results show that the tracked chassis can be fully adapted; for the wheeled chassis,the loading amount needs to be reduced; for the truck chassis,the position of seat ring needs to be adjusted; and for the amphibious chassis,the weight needs to be reduced by more than 55%.The design process and evaluation method significantly improve the simulation and optimization design efficiency of gun equipment,and can be directly applied to the similar problems of more design variables and working conditions,providing a strong technical support for the modular design and optimization of weapon equipment.

In order to improve the magnetic adsorption efficiency and uniform magnetic field distribution in the limited installation space of wall-climbing robots,a Halbach-based rectangular closed-loop magnetic array adsorption module and parameter optimization method are proposed.This module improves the magnetic force attenuation and leakage caused by the end effect of the linear classical Halbach magnetic array adsorption module,and has the characteristics of easy installation and uniform magnetic force distribution.The structural configuration with high adsorption efficiency is determined by establishing a magnetic force attenuation model considering the end effect and studying the influence of magnetic circuit structure change on magnetic field distribution and gradient through simulation.The key structural dimension parameters are extracted and integrated,and a nonlinear regression prediction model is established using the random uniform sampling strategy and the response surface method.The structural parameters are optimized by the particle swarm optimization algorithm to obtain the optimal combination of magnetic adsorption force parameters.The results show that the proposed prediction model exhibits high credibility and accuracy,and its average relative error is only 1.5184%;and the optimized design of the rectangular closed-loop magnetic array adsorption module increases its magnetic performance by 33.54%.The tensile force experiment of magnetic adsorption module and the obstacle clearance test of robot are conducted to verify the effectiveness of optimization process.The wall-climbing robot performs well on curved surfaces and wall environments containing weld obstacles.

As an important part of control system for a guided projectile,the solder joints of projectile-borne electronic package will be subjected to a high overload of tens of thousands of g for several milliseconds in the chamber during launching,which is easy to cause overload damage.However,the failure analysis of solder joints of projectile-borne electronic package is difficult due to the complex loading environment in the chamber and the coupling effects of various loads.In order to research the failure mechanism of solder joints of projectile-borne electronic package with high overload,the electronic package is tested on an air cannon test platform.The mechanical responses of electronic package under different overload conditions are obtained by through the test,and the damage detection and failure analysis of electronic package are carried out.A numerical simulation model of electronic package solder joints is established and simulated to obtain the mechanical response characteristics of electronic package solder joint under high overload environment.The research results show that the stress of the solder joints in the vertical load direction is less than that in the parallel load direction,and the increase of the load amplitude will increase the solder joint stress,while the increase of the load pulse width will decrease the solder joint stress.It provides a reference for failure analysis of solder joints in projectile-borne electronic packages.

The thickness equivalence of composite radome under the far-field explosion loads is studied by taking the fiber-reinforced polymer (FRP) laminate as the research object.A serial artificial neural network (S-ANN) model based on the principle of deflection equivalence is proposed to predict the thickness equivalence relationship between glass fiber radomes with different performances.A finite element model for the dynamic response of FRP laminates under explosive loads is established.The maximum deflection of FRP laminates under the conditions of different detonation distances,laminate thicknesses,densities,and longitudinal elastic moduli is obtained by conducting batch calculations on this finite element model.Based on this,a S-ANN thickness equivalence model is established.The proposed model achieves the thickness equivalence for different types of FRP materials under far-field explosion loads.In addition,the frequency response characteristics of the glass fiber equivalent radome are analyzed using the \overline{A}\overline{B}\overline{C}\overline{D} transmission matrix and a numerical simulation method.The research results show that the longitudinal elastic modulus has the greatest influence on the explosion resistance and equivalent thickness of glass fiber radome under far-field explosion loads.The equivalent thickness has little influence on the amplitude of the radome’s transmission efficiency,but it changes the resonant frequency of the radome’s transmission efficiency.This study can provide reference for the thickness equivalence research and optimization design of radomes.

With the transformation of the future war to all-domain operation mode,the ammunitions used for combat weapons will be inevitably subject to extreme high or low temperature in storage,transportation and utilization environments.Nitroguanidine gun propellant has high energy and low ablative properties,which is widely used in large-caliber weapons.In order to study the mechanical and combustion properties of ultra-thick gun propellant (4.2mm thickness) for a ship-borne large-caliber weapon,the thermal decomposition behavior,mechanical and combustion characteristics of ultra-thick nitroguanidine gun propellant with thickness of 4.2mm are studied by the differential scanning calorimeter-thermogravimetric analysis (DSC-TG),the closed bomb test,the charpy impact strength test and the critical crushing strength test of drop hammer,respectively.The structure morphology and composition of gun propellant is characterized through scanning electron microscope (SEM),Fourier transform infrared spectrometer (FT-IR) and X-ray photoelectron spectroscopy (XPS).Results demonstrate that the ultra-thickness nitroguanidine gun propellant has stable combustion behavior at different temperatures.The combustion curve is smooth without step,which conforms to the combustion law of gun propellant.The critical breaking height and impact strength of the ultra-thick nitroguanidine gun propellant are higher and larger than those of an approved azido-nitroguanidine gun propellant,under the conditions of the same thickness and drop weight,moreover,the impact-resistance strength of the simply supported beam is more than 1.6 times that of the azido-nitroguanidine gun propellant.It demonstrates that the mechanical properties of ultra-large thickness nitroguanidine gun propellant is considerable excellent.Additionally,the ultra-thick nitroguanidine gun propellant exerts good thermal stability.Hence,this present work prospectively to provide basic support and guidance for the development of ultra-thick gun propellant used by large-caliber weapon for shipborne and other high-performance combat platforms in the future.

To address the limitations of existing traversability analysis methods,which often suffer from incomplete obstacle recognition and poor generalization in complex off-road environments,this paper proposes an obstacle recognition method based on open-vocabulary semantic segmentation.The method extracts the semantic labels of obstacles and terrain around the vehicle,enabling effective identification of previously unseen obstacles in unstructured environments.The method is validated on the datasets in real-world experiments,demonstrating its stability and comprehensive recognition capability.On this basis,a multi-layer 2.5D map is constructed by integrating semantic labels with 3D point clouds.The traversability level of a terrain is preliminarily classified according to semantic labels.And then the terrain smoothness is quantified based on ground elevation,and the geometric parameters of special environmental features (e.g.,vertical wall) are measured.Furthermore,the driving posture of vehicle is predicted by incorporating the geometric configuration of a tracked vehicle,thereby quantifying the coupling relationship among static slope stability,semantic terrain categories and geometric attributes.A cost function is then designed to jointly assess the traversal risk and cost of vehicle,ultimately generating a vehicle-centric traversability map.The effectiveness and reliability of the proposed method are verified by comparing it with similar methods,which enhances data support for decision-making,planning,and control of unmanned tracked platforms.

A cooperative encirclement interception method based on virtual aiming points is proposed for intercepting the high-speed maneuvering targets in near-space in three-dimensional scenarios.A calculation method for the ideal interception time of interceptor groups is derived by analyzing the maneuvering envelope of target and considering the guidance characteristics of the interceptors.Thus,the problem of intercepting the high-speed maneuvering targets is transformed into a problem of hitting a specific point on a fixed spatial plane at a predetermined time and angle.Based on the ideal interception time and angle of attack,the virtual aiming points are selected in space to guide the interceptors,ensuring that the impact angles meet the head-on interception conditions,thereby reducing the requirement for the speed of interceptor.The interception tests are conducted on two typical C-type and S-type maneuvering targets through numerical simulation.The results demonstrate that the proposed method is used to successfully intercept C-type and S-type maneuvering targets with different maneuvering intensities,achieve a minimum group miss distance of less than 3 meters,and enable the impact angle meet the requirements of head-on interception angle.

To address the issue of evading a medium-long range air-to-air missile in beyond visual range (BVR) air combat,a feasible maneuver strategy for unmanned aerial vehicle (UAV) possessing the capability of high overload lateral maneuver within a short period of time to evade the medium-long range air-to-air missile in terminal guidance is proposed based on the characteristics of UAV equipped with lateral rocket boosters.A model of UAV and medium-long range air-to-air missile is established.The influences of lateral overload activation time,lateral overload size and lateral overload direction on the miss distance of a missile are investigated.The experimental results show that the UAV utilizes the maximum available lateral overload within the sustainable time to evade the air-to-air missiles.When a missile is approaching head-on,UAV climbs to evade it,while the same direction climbing and diving maneuvers are used to against the missile approaching from the front.

Studying underwater explosions near warships is crucial for hull structure design,explosion impact damage prediction,and personnel safety.To this end,an improved six-equation compressible multiphase flow model based on the diffuse interface method is proposed to resolve thermodynamic state prediction deviation under shock waves and support anti-shock mechanism research and numerical method optimization.The model is improved via a hybrid energy correction equation and a more accurate gas equation of state.A numerical algorithm on an unstructured grid system is constructed,adopting the second-order MUSCL-Hancock scheme (with least-squares reconstruction and Barth-Jespersen limiter) and two-phase HLLC Riemann solver to solve homogeneous hyperbolic equations,and Newton-Raphson iteration for instantaneous pressure relaxation equation.Results show that after total energy equation correction,the model’s simulation of shock wave velocity and interface is highly consistent with the Euler equation’s exact solution,resolving near-interface numerical oscillation.Compared with experimental data,the improved model has a 1.13% relative error and 0.33% higher accuracy; more accurate SG-EOS parameters are obtained by fitting the shock Hugoniot curve.It also clearly shows underwater explosion phenomena:shock wave propagation,bubble expansion-contraction,and bubble collapse water jet.However,it has deficiencies in bubble interface clarity and jet precision,mainly limited by numerical scheme dissipation under extreme gradients.In conclusion,the improved model effectively enhances the accuracy of simulating underwater explosions near naval vessels,supports in-depth warship anti-shock mechanism research,and lays a solid foundation for future numerical method optimization.

To address the susceptibility of underwater time of arrival localization techniques to ranging errors,this paper proposes a similarity matching localization algorithm based on the L_p norm constraint (LPM).First,a distance vector model including the environmental parameters is established,and a similarity matching localization algorithm is formulated.By calculating the L_p norm between the measured distance vector and its replica,the similarity analysis is performed to achieve the three-dimensional (3D) localization of target in the observation area.To verify the performance of the proposed algorithm,Monte Carlo simulations are conducted to compare LPM with the least squares method,and analyze the horizontal localization errors and the distribution law of localization errors in 3D space.Furthermore,validates the algorithm is verified through water tank experiment,demonstrating that the mean localization error decreases from 0.0555m to 0.0256m,and the error standard deviation reduces from 0.0345m to 0.0072m.The simulated and experimental results indicate that LPM has error distribution characteristics similar to that of conventional localization method.LPM achieves higher precision and robustness due to the direct matching of distance vectors without coupling error propagation.Additionally,the algorithm considers the influence of environmental parameters on ranging,so it has the ability to deal with the variation of sound velocity gradient with space.

In order to investigate the influence of bubbly flow on propeller wake,the wake dynamics characteristics of propellers in bubbly flow are numerically studied based on the SST k-ω DES turbulence model and volume fraction equation,and the sliding grid technique.The KP505 propeller flow numerical model is verified.A propeller wake evolution model is proposed based on the evolution mechanism of propeller wake in multiphase inflow.The results show that the proposed model can accurately simulate the evolution process of propeller wake and reveal the triggering mechanism of propeller wake instability.The radial ventilation position affects the strength and dissipation of the tip vortex and hub vortex of propeller.The ventilation at the axis causes the hub vortex to expand and connects the tip vortex to form a vortex ring in the far field.The ventilation position moves towards the wing tip,and the vortex system at the wing tip accelerates and rapidly dissipates.The results have certain reference value for the design and manufacturing of propellers.

The wide-area imaging becomes difficult due to the small overlapping area of multi-camera images,large parallax,and complex and changeable feature information in practical application scenarios when a multi-camera detection system is used to provide environmental perception for military vehicles such as tanks and armored vehicles.A wide-area real-time imaging algorithm based on ChArUco board calibration is proposed,and a wide-area visual enhancement system for military vehicles is designed for drivers to perform real-time imaging of the external environment in a closed compartment with limited vision.This algorithm takes advantage of the characteristic that the ChArUco board can still be accurately calibrated under occlusion conditions to achieve the accurate calibration of a small-overlapping multi-camera system.Projection transformation is carried out through calibration parameters to avoid the interference of image feature information and effectively deal with complex feature scenarios.At the same time,the parallax in the overlapping area is eliminated by the fusion of optical flow relationships,and a wide-area real-time imaging is achieved by using the projection look-up table and parallel acceleration optimization method.This algorithm is deployed on a mobile computing platform to form a complete wide-area visual enhancement system.The experimental results show that this system and algorithm can meet the wide-area real-time imaging requirements of various scenarios and improve the visual perception ability of military vehicles in complex environments.

Active sonar buoy is widely used as a submarine detection equipment for anti-submarine aircraft.It is of great significance to study its deployment optimization method to quickly and effectively complete the anti-submarine tasks and improve the efficiency of anti-submarine combat.The problem in current research lies in the fact that the submarine position distribution model and the simplified search range of active sonar buoys for detecting the submarines are difficult to meet the needs of the actual scenario.A distribution law model of submarines under the conditions of known general heading and unknown speed and an evaluation model of active sonar buoy array search efficiency based on the active sonar equation and the grid method are established.A buoy array deployment optimization method based on improved multi-objective particle swarm optimization algorithm is proposed by introducing Kent mapping,dynamically adjusted inertia weight and learning factor.The simulation verification is carried out in the scene of on-call submarine search.The simulated results show that the proposed algorithm can be used to obtain the optimal deployment scheme in different scenarios,which proves its feasibility and effectiveness.Compared with other algorithms,the proposed algorithm has a larger search probability and a shorter computation time under the condition of the same delivery amount,which proves its superiority.

An improved particle swarm optimization (IPSO) algorithm is proposed to optimize the optimal aiming point of multiple projectiles against complex-shaped surface targets.When constructing an aiming point selection model,the influences of complex factors such as surface target area shape,regional correlation,ammunition power area,ammunition hit accuracy,cumulative damage and multi-projectiles combined damage on target damage effect are considered comprehensively.Particle swarm optimization (PSO) algorithm is improved by preassigning the particle positions and introducing the particle activation energy,which not only improves the convergence speed of the algorithm but also ensures the global search ability.The proposed algorithm is verified through typical complex target test cases.The results show that,compared with Monte Carlo algorithm,PSO algorithm and improved grey wolf optimization algorithm,the IPSO algorithm has a better ability to select aiming points,and increases the average damage yield by 4.3%.And the average computation time for aiming point selection is only 1/4-1/3 of that of traditional optimization algorithms.,which has obvious advantages in damage income and computing efficiency.

Aiming at the problem that the stabilization system of unmanned vehicle-mounted guns is affected by the complex nonlinearity and random disturbances during moving,a composite control strategy combining active disturbance rejection adaptive control is proposed.The electromechanical coupling dynamic equations of the unmanned vehicle-mounted gun stabilization system, which take into accountconsidering the actuator dynamics and model uncertainties,are established.Based on the backstepping approach,the adaptive control is ingeniously integrated with the extended state observer (ESO),constructing the parameter adaptation laws to update the unknown parameters of the system online.A dual-channel ESO is used to estimate the matched and unmatched disturbances in real time and provide feedforward compensation.Since the parameter uncertainties of the stabilization system are mainly addressed by adaptive technology,the learning burden of ESO is further reduced,improving the tracking performance of the stabilization system during moving and avoiding the impact of high-gain feedback.The stability analysis based on the Lyapunov function indicates that the asymptotic control of the vehicle-mounted gun can be achieved when only constant disturbances are present,and even in the presence of time-varying uncertainties,the prescribed transient performance and tracking accuracy can still be ensured.Comparative co-simulations and simulation tests demonstrate the effectiveness and feasibility of the active disturbance rejection adaptive composite control strategy.

To evaluate the performance of tracked vehicles,a multiple road surfaces-three-dimensional driving cycle construction method based on micro-motion segments is proposed.This method aims to address the issues of various types of road surfaces,longer short-trip segments,and the numerous dimensions of influencing factors in the construction of driving cycles for tracked vehicles.The collected driving data of tracked vehicles is processed,and the three-dimensional data such as speed,angular velocity,and ground resistance coefficient are extracted.The K-means clustering method is used to categorize the driving segments into three typical road surfaces:paved road,gravel road,and undulating dirt road.The short-trip segments are divided into micro-motion segments based on their minimum weighted three-dimensional variation rate,and the feature extraction and clustering analysis are made for the short-trip segments.A three-dimensional driving cycle is constructed using the Markov transition probability of the micro-motion segments,and a corresponding comprehensive evaluation system is proposed.The total duration of the constructed driving cycle is approximately 2000 seconds,and the average feature coverage rate of three types of road surfaces is up to 94.63%.This driving cycle accurately reflects the driving characteristics of tracked vehicles and serves as an effective tool for simulation and bench testing of tracked vehicles.

To precisely control the assembly position-orientation accuracy of gyroscopic pendulum accelerometers at the design stage,this paper proposes an computing method of position and orientation deviations (PODs) considering the flexible contact behaviors of non-ideal mating surfaces.A mathematical model based on multi-degree-of5freedom force equilibrium conditions is established by adopting an iterative trial adjustment strategy for position and orientation,and a non-dominated sorting genetic algorithm Ⅲ (NSGA-Ⅲ) framework is developed for solving the proposed model.The proposed method is comparaed with the classical small displacement torsor (SDT) method and the mainstream iterative closest point (ICP) algorithm,and its effectiveness and accuracy are validated through a case study of coaxial assembly accuracy prediction for gyroscopic pendulum accelerometers.Results indicate that the proposed method can be used to improve the predicting accuracy of assembly position-orientation,offering technical support for ensuring the precision performance in high-end inertial nvigation systems.

The effects of the ignition and combustion characteristics of boron particles in a solid rocket scramjet engine and the combustor structure on the combustion performance of engine are studied.A user-defined function program for characterizing the ignition and combustion processes of boron particles is written,and the dynamic characteristics of combustion energy release of condensed-phase particles in a ramjet is analyzed.Furthermore,based on the orthogonal design experimental method,the effects of boron particle size,gas injection angle and cavity depth,as well as their interactions on engine combustion efficiency are analyzed from the perspectives of particle characteristics and engine structure.Through range and variance analyses,the results indicate that the factors influencing the engine combustion efficiency are ranked as follows:boron particle size > interaction between particle size and gas injection angle > gas injection angle > cavity depth > interaction between gas injection angle and cavity depth > interaction between particle size and cavity depth.The optimal combination achieves a combustion efficiency of 77.01%.The boron particle size has a significant effect on the combustion efficiency of solid rocket scramjet engine,and the interaction between particle size and gas injection angle cannot be ignored.

In view of the two typical failure modes of breechblock opening-closing mechanism for a naval gun,namely the wear of the key parts and the weakening of spring elasticity,the traditional fault diagnosis methods mainly rely on manual inspection,expert empirical reasoning and theoretical simulation.However,these methods not only take a long time for diagnosis,but also the diagnostic accuracy cannot be guarantee.In order to solve this problem,a fault diagnosis method of Gram angle field combined with convolutional neural network and long short-term memory neural network (GAF-CNN-LSTM) based on sparrow search algorithm (SSA) is proposed by using the deep learning algorithms.Firstly,the original fault signal of the breechblock opening-closing mechanism is collected and preprocessed by the test bench,and the one-dimensional time-series data and two-dimensional image fault dataset are established by the time-frequency analysis method and the Gramian angular field method.Then the fault dataset is input into the LSTM and CNN channels,respectively,and the powerful spatial feature extraction ability of CNN and the time-series feature ability of LSTM mining data are used to extract the features,and the feature informations obtained by the two abilities are fused to output the diagnostic results under the action of the fully connected layer and activation function.Finally,the SSA optimization algorithm is used to optimize the hyperparameters in the GAF-CNN-LSTM network structure to improve the diagnostic accuracy and applicability of the model.The proposed SSA-GAF-CNN-LSTM fault diagnosis model is verified by the test data.The result shows that the proposed fault diagnosis model can not only diagnose the fault type of the breechblock opening-closing mechanism for naval gun more accurately,but also has stronger generalization ability and anti-interference ability,which effectively improves the fault diagnosis performance of the breechblock opening-closing mechanism.

The water-jet propeller is main propulsion plant of amphibious vehicle when it navigates on the surface.There are significant differences in the vehicle body attitude and the inflow conditions of propeller at different navigation depths in the land-water interface zone,which significantly affects the propulsion performance.In order to study the mutual influence of amphibious vehicle and water-jet propeller under water depth conditions,this paper takes water jet propulsion amphibious vehicle as the research object,and uses the finite volume method,the shear stress transport (SST) turbulence model,the volume of fluid (VOF) two-phase flow model and the dynamic fluid body interaction (DFBI) motion model to numerically calculate the hydrodynamic performance of the pump-vehicle-integrated amphibious vehicle at different rotational speeds of water-jet propeller under different water depth conditions.The grid uncertainty is analyzed,and the accuracy of the algorithm is verified by comparing the calculated values with the experimental results.The motion law,flow field distribution characteristics and hydrodynamic performance of the pump-vehicle-integrated amphibious vehicle under different navigation conditions were obtained through analysis.The results show that,in the deep water environment,the amphibious vehicle is in the drainage sailing state,and the body attitude of vehicle changes greatly when sailing at a low speed,which affects the stability of the axial flow of fluid in the propeller; the body sailing state of vehicle and the flow rate and head of propeller are relatively stable when sailing at a high speed.In shallow water environment,the amphibious vehicle is in subcritical state when sailing in low speed and has larger longitudinal inclination and sinking amount than those in deep water environment,and the resistance of the vehicle body is increased by 13.65% on average.When sailing at high speed,the amphibious vehicle enters into the supercritical state,the vehicle body floats up rapidly,and the sailing speed is the same as that under the deep water condition.And after the stabilisation,the amplitude of attitude change is small,and the stability of propeller performance is improved.In the shallow water environment with different depths,the vehicle body in the shallower water environment is more obviously affected by the shallow water effect and is subjected to greater resistance during low-speed navigation,while there is no obvious difference in the hydrodynamic performance of amphibious vehicle at different depths during high-speed navigation.Therefore,the amphibious vehicle should increase the output power of the propeller when passing through the shallow water area and quickly enters the supercritical state to reduce the influence of shallow water effect on it.

The ceramic/fiber composite ballistic plates are widely used in personal protection equipment. Studying the performance of ballistic plate subjected to multi-impacts is of great significance for reducing the number of casualties in the battlefield.This paper investigates the Al₂O₃/UHMWPE composite ballistic plate,focusing on numerical simulations conducted for various bullet impact points.The reliability of the simulated results is validated by comparing with the experimental results.The relationship between the energy absorption and damage characteristics of the ballistic plate is derived from the ceramic and fiber damage results,and the penetration probability of the next impact is effectively calculated.The results indicate that the damage patterns of ballistic plates are roughly the same and the impact resistance of ceramic layer at the joint decreases.when the impact point of the first bullet is located at the center of a ceramic plate,within the gap between two plates,or at the gap of quadrilateral jointing.Specifically,when the impact point of the first bullet is located at the center of ceramic plate,the subsequent bullets tend to penetrate through the gap between adjacent plates.As the proximity between successive impacts decreases,the energy absorption by the ceramic layer diminishes while the energy absorbed by the fiber layer increases.When two impact points are located parallelly and diagonally apart,the middle ceramic plate does not suffer macroscopic damage due to the joint structure.When the first impact point is in the center of the ceramic plate,the penetration probability of the second impact is 1.04%.When the first impact point is in the center of the ceramic plate,and the second impact point is in the horizontal adjacent center,the four corners of the gap,or the diagonal adjacent center,the penetration probability of the third impact on the ballistic plate is 5.45%,7.35%,and 5.05%,respectively.This method can be used to quickly evaluate the resistance of damaged equipment to multiple penetrations.