In traditional chined waverider design, the adjustment of design profile parameters is complex and the design intuitiveness is insufficient. To address these issues, this paper proposes a chined upper surface design method based on B-spline curves. The design flexibility and convenience are improved by directly adjusting the design profile through control points. The base profile is constructed by means of Bezier curves, the leading edge and lower surface base profile are determined using the osculating cone theory, and the upper surface profile is designed using cubic and quadratic B-spline curves. The reliability of the proposed method is verified by computational fluid dynamics (CFD) methods, and the aerodynamic performance of the chined waverider is analyzed. The results demonstrate that, as the angle of attack gradually increases, the influence of the chined upper surface on aerodynamic characteristics weakens gradually, and the maximum lift-to-drag ratio appears at the angle of attack ranging from 4° to 6°. The proposed method provides a more intuitive profile optimization means for waverider design, which has reference value for engineering design.

To improve the resistance of B₄C/Al composite targets against explosively-formed projectile (EFP) penetration, the surface morphology of ceramic strike face is modified. Seven types of B₄C/Al composite targets featuring different protrusion-array structures on the strike face are examined. The processes of EFPs penetrating into the composite targets at 1.5, 1.7, and 1.9 km/s are simulated using LS-DYNA. The evolutions of the projectile's mass, velocity and kinetic energy during penetration are analyzed. The results indicate that B₄C/Al composite targets with protruded strike-face structures exhibit superior penetration resistance and deceleration capability compared with B₄C/Al flat-faced targets. Among them, the composite target with a pyramidal protrusion array provides the best deceleration performance for the simulated EFP.The R3 semi-cylindrical target demonstrates the best protective performance under normal impact. The penetration direction significantly affects the penetration resistance of anisotropic protrusion-array targets and the sinusoidal-structured target has the optimal protection performance under oblique impact.

The mechanical properties of high-entropy alloys (HEAs) are studied. For this purpose, a simple and precise testing system is established for determining the equation-of-state parameters of HEAs. Based on the principle of wave impedance matching, a test setup is designed using the pressure comparison method to obtain the shock adiabat data of HEA materials. The acquired experimental data is then optimized through adaptive clustering detection. After optimization, the confidence intervals for the slope and intercept of the experimentally determined shock adiabat are narrowed from [1.66293, 2.03332] and [4.01158, 4.38089] to [1.6461, 1.92734] and [4.15248, 4.27542], respectively, and the coefficient of determination (R²) is improved from 0.9687 to 0.9849. The Hugoniot equation-of-state parameters for the HEA are determined as C₂=4.214km/s and λ₂=1.787.The Hugoniot equation of state established in this study is applicable within a pressure range of approximately 5.86-32.77 GPa, and its extrapolation to higher pressure regimes necessitates further experimental validation to guarantee reliability. The results demonstrate that the proposed system achieves high-precision measurement of equation-of-state parameters for high-entropy alloys hrough the combination of data optimization algorithms with experimental design. This work provides critical technical support for the performance assessment and practical application of such materials under dynamic mechanical conditions.

To address the issue of small penetration aperture in traditional shaped charge warheads against underwater single-layer targets,a novel W-shaped shaped charge structure design method based on the inner cone angle α and outer cone angle β is proposed.The influence of liner structure on jet formation and damage effectiveness is studied.The ratio μ of the lengths of the inner and outer sides of the liner is defined a-s a characterization parameter affecting the underwater formation and damage performance of the W-shaped liner.The influence of the ratio μ on the formation and initiation points on the formation and penetration of annular jet are analyzed through numerical simulations.The results indicate that,the annular jet converges excessively toward the axis when μ is 0.22,forming an explosively formed projectile (EFP).When 0<μ<1,the outward expansion trend of the annular jet gradually intensifies,the head-to-tail velocity difference decreases,and the jet stability improves with the increase in μ.When μ>1,the slug at the jet tail is reduced,the jet head expands,the head-to-tail velocity difference increases,and the jet stability significantly decreases under the influence of the external water medium with the increase in μ.Additionally,the increase in the number of initiation points induces necking at the head of the annular jet,which has little impact on penetration and aperture formation under the condition of small standoff distance.The large-area damage of annular jet to the target plate can be achieved by optimizing the combination of the inner and outer cone angles of the liner to adjust the value of μ and the number of initiation points.

The penetration tests on three sets of geometrically similar projectiles with scaling ratios of 1/1, 1/2 and 1/3 are carried out to investigate the size effect of penetration depth of projectile into concrete media. A calculation method for penetration depth with the projectile diameter coefficient as a variable is proposed, and a conversion coefficient model that takes into account the scaling ratio is established for penetration depth. The dynamic strain rate of material in the projectile-target contact zone during the penetration processare quantitatively analyzed through numerical simulation, and the values of penetration depth conversion coefficients under different scaling ratios are ultimately determined. The results show that the size effect exists in the dimensionless penetration depth between the prototype projectile and the model projectile, which arises from the difference in the average strain rates of target in the tests with different scaling ratios. The strain rate increases with the increase of penetration velocity and the decrease of projectile diameter, and does not conform to the geometric similarity scaling relationship. The established penetration depth conversion coefficient is correlated with the target strain rate and the scaling ratio. This conversion coefficient not only quantifies the influence of the material strain rate on the size effect, but also clarifies the mechanism of the size effect of penetration depth in concrete media from a mechanistic perspective.

In modern warfare, the damage efficacy of high-speed penetration weapons against high-strength targets such as underground bunkers and reinforced structures has become a focal point of research. This paper systematically reviews the research progress on the dynamic behavior of projectile materials, constitutive models, and structural responses under high-speed penetration. It analyzes the mechanisms of strain hardening, thermal softening, and adiabatic shear deformation under the coupled effects of high temperature and high strain rate, and compares the applicability of typical constitutive models such as the Johnson-Cook model. Key factors influencing mass erosion, critical instability velocity, and structural failure during high-speed penetration are emphasized, along with their underlying mechanisms. Additionally, technical approaches to enhance penetration capabilities through material optimization and structural design are explored, providing valuable references for researchers in related fields.

The influence of grooved structure on the penetration and damage performance of copper-aluminum/polytetrafluoroethylene (Cu-Al/PTFE) energetic composite liner is investigated.A energetic composite liner with large cone angle (140°) is numerically simulated and experimented,and the damage effect of a pre-grooved energetic composite liner on concrete target is examined.A comparison shows good agreement between the experimental and simulated results.The influences of groove structure parameters such as groove width,depth,and wall thickness ratio on the damage effect of jet are further analyzed.The results show that the groovee structure has an effect on the distribution of jet energy between radial expansion and axial penetration.The smaller widths,shallow depths and narrow spacing of grooves are conducive to the radial hole enlargement,whereas the larger widths,greater depths and wider spacing of grooves enhance energy concentration,thereby increasing the penetration depth.Additionally,the number of grooves and the wall thickness ratio significantly influence the stability of jet and the ability of reactive materials to follow up.In particular,a wall thickness ratio of 1∶1 between the copper and reactive material layers yields favourable jet formation and damage performance.

The direction-finding performance of guidance and direction-finding system is limited with a small-aperture array and the array configuration optimization is a key step to improve system performance due to platform resource constraints such as weight,volume,and deployment space.In this paper,the Cramér-Rao bounds (CRBs) for wideband two-dimensional direction-of-arrival (DOA) estimation of both scalar arrays and polarization-sensitive arrays are derived,and a CRB-based performance evaluation and configuration optimization method for small-aperture arrays is proposed.Firstly,the development of wideband DOA estimation and the typical two-dimensional array structures are reviewed,and the wideband signal models based on subband decomposition are established for both scalar arrays and polarization-sensitive arrays.For scalar arrays,a closed-form expression for the CRB of wideband two-dimensional DOA estimation is provided.Subsequently,a general framework and closed-form expression for the CRB of wideband two-dimensional DOA estimation of polarization-sensitive arrays are derived,and a performance evaluation criterion for two-dimensional direction finding with such arrays is established.Finally,A two-dimensional array configuration optimization method based on the derived CRB is proposed by considering the constraints ofguidance system platform on the number of array elements and array aperture.The quantitative optimization of array layout can be achieved by constructing an array configuration optimization set and conducting theoretical performance evaluation.The research results provide theoretical support and technical guidance for the array configuration design and performance evaluation of small-aperture guidance direction-finding systems.

In response to the application requirements of inertial navigation systems for quartz flexible accelerometers with a large range and high dynamic flight accuracy, a new structure for the pendulum assembly of quartz flexible accelerometer is proposed to enhance the range and second-order coefficient of accelerometer. A mathematical model of the designed pendulum assembly is established to derive the scale factor of the designed accelerometer. The design range of accelerometer is theoretically calculated based on the load capacity of servo circuit. The optimization method for the second-order coefficient of the accelerometer is analyzed, and an optimization scheme for the second-order coefficient is provided. Through numerical simulations, it is verified that the deflection and stress of the designed pendulum assembly under full-scale conditions meet the design requirements. Experimental results show that the quartz flexible accelerometer achieves a range of 110g and a second-order coefficient better than 5 μg/g², thereby improving the dynamic application capability of quartz flexible accelerometers in inertial navigation systems.

Aiming at the path planning problem of UAVs in complex scenes,this paper proposes a coupling algorithm that uses the improved A-star algorithm and the improved dynamic window method for path planning,so that the UAV has the ability to avoid static and dynamic obstacles.In terms of global planning,by improving the evaluation function of the A^* algorithm,a path planning algorithm that does not rely on the obstacle expansion map is proposed,so that the UAV can plan a safe path against a priori static obstacles.In terms of local planning,an evaluation function for handling dynamic obstacles is added,so that the UAV has good obstacle avoidance capabilities when facing high-speed dynamic obstacles.Aiming at the problem of too many inflection points on the path resulting in frequent acceleration and deceleration after improving the global planning algorithm,a redundant inflection point deletion strategy was proposed.The simulation results show that compared with the traditional algorithm,the improved algorithm has better obstacle avoidance ability and shorter driving trajectory,which verifies the practicability of the algorithm.

This paper investigates the guidance of missiles striking the maneuvering targets in three-dimensional (3D) space in the presence of model uncertainties, unknown target maneuvers and terminal impact angle constraints. An impact angle control guidance law based on nonsingular fixed-time sliding mode control (NFTSMC) and fuzzy logic is proposed. First, a 3D missile-target relative motion model is established, and the terminal impact angle constraint control is reformulated as a line-of-sight (LOS) angle tracking problem. To overcome the singularity commonly encountered in conventional terminal sliding mode control, a nonsingular fixed-time sliding mode surface (NFTSMS) is constructed, and an auxiliary function is introduced to guarantee singularity-free controller design. In addition, a fuzzy logic system (FLS) is incorporated to online approximate the lumped disturbances induced by target maneuvers and model uncertainties. The fixed-time stability of all signals from the closed-loop system is strictly proved based on Lyapunov stability theory. The simulated results show that the proposed guidance law can achieve the accurate interception of maneuvering targets under different initial conditions. Compared with the existing fixed-time sliding mode guidance strategy, it has significant advantages in suppressing the control command chattering and improving the line-of-sight angle tracking accuracy.

To address the low decision-making efficiency and poor practicality of weapon-target assignment (WTA) in modern air-defense operations,a multi-objective WTA model that comprehensively considers four performance metrics including ammunition consumption,operational cost,total engagement time,and interception benefit is constructed.Practical constraints such as weapon-ammunition compatibility,ammunition inventory,and damage thresholds,etc,are also taken into account to enhance the battlefield applicability of the model.Secondly,a hybrid heuristic algorithm—hybrid ahaotic quantum particle swarm optimization-variable neighborhood search (HCQPSO-VNS) is proposed to solve the proposed WTA model.In the proposed algorithm,a logistic chaotic mapping is employed to improve the quality of the initial population,the quantum particle swarm optimization (QPSO) is utilized for global search; and the variable neighborhood search (VNS) with multiple neighborhood structures is integrated for local optimization to avoid premature convergence.Simulated results demonstrate that the proposed algorithm converges to a high-quality feasible solution within very few iterations.The obtained assignment schemes satisfy the expected lower bounds for damage,weapon-ammunition compatibility,and other constraints,while achieving an effective balance among four performance metrics.Comparative analysis shows that the overall performance of the proposed algorithm outperforms several mainstream algorithms,and can effectively improve the efficiency and scientific rigor of air-defense firepower allocation decisions.Meanwhile,as the problem complexity increases,the proposed algorithm retains high optimization efficiency and acceptable computational load,demonstrating favorable scalability.

In recent years, the development of large-scale low-earth-orbit (LEO) satellite constellations has been progressing at an unprecedented pace, and their potential applications in the military domain have become increasingly prominent. These constellations possess unique technical characteristics that enable them to restructure the traditional kill chain, effectively addressing core challenges such as reconnaissance delays and insufficient cross-domain coordination in precision strikes. This paper provides a comprehensive introduction to the development of large-scale LEO satellite constellations and delves into their application directions in the military field. By examining typical combat scenarios from the perspectives of the kill chain and kill web, this paper analyzes how large-scale LEO satellite constellations can enhance the construction of the kill web and facilitate the closure of the kill chain in the field of precision strike. The findings of this study offer valuable insights and references for the construction of a global and systematic kill web based on a large-scale low-Earth-orbit constellation. Moreover, this research holds significant reference value for the development of China’s anti-access/area denial (A2/AD) strategic system architecture. As related projects in our country continue to advance steadily, the exploration of the potential of large-scale LEO satellite constellations in enhancing military capabilities becomes even more crucial.

The modal parameters of large-scale missile and rocket systems are generally obtained through finite element analysis and ground vibration tests.Due to the inability to simulate the time-varying characteristics of the system under flight conditions,it is usually necessary to conduct finite element modeling or ground vibration tests based on several characteristic conditions,and finally obtain the flight modal frequency through numerical interpolation.The repeated modeling and ground testing process is time-consuming and laborious.This article presents a fast prediction method for time-varying modal parameters of missile and rocket,which is based on the concentrated mass beam model and finite element method.This method introduces time-varying mass matrix,stiffness matrix,and damping matrix to describe the time-varying system,which can quickly provide the time-varying modal frequency parameters of the system.This method has been validated through ground vibration test and flight test,the results show that this method can reliably simulate the time-varying modal parameters of the system,effectively solving the pain points of the tedious simulation of time-varying systems.Moreover,the time-varying dynamic response data obtained based on this method can be used for dynamic inverse problems such as the modal consistency analysis and load identification.

In order to study the spinning projectile stability of coning motion,provide the dynamic equation around the center of mass in quasi-body coordinate system and establish the short period dynamic model.Derive the equations of coning motion represented by Euler angles.Obtain the analytical solution by introducing complex angle of attack.Analyze the stability of coning motion with initial disturbance in two cases:One situation is ignoring the Magnus effect and damping effect,only analyze the coning motion influenced by the gyroscope effect and the aerodynamic static moment.Another situation is the coning motion adding in the Magnus effect and damping effect,analyze the stabilization and provide the conditions for coning stability.Finally,summarize the influence of rotating speed and statically stability acting on the dynamic stability of coning motion based on theoretical analysis and simulation results:For the low-speed rotating missiles,only under the influence of gyroscopic effect and aerodynamic static moment,a statically stable aerodynamic shape is necessary to achieve coning stability.Statically unstable missiles can only achieve dynamic stability by significantly increasing the rotating speed.Considering the Magnus effect and damping effect,the convergent coning motion of the statically stable missiles with low rotating speed is the easiest to achieve.The divergence of coning motion may occur result in the increasing of rotating speed.For the statically unstable missiles,it is necessary to select the moment of inertia reasonably and increase the rotating speed to achieve dynamic stability.

Random vibration screening test is essential for the development of on-missile electronics used in steering gear control drivers, whether the structure of the vibration test fixture is reasonable plays an important role in the accuracy and reliability of the test. To combat some problems such as excessive mass, poor vibration transmission characteristics and so on existing in this kind of vibration test fixture, a method of optimization design by comprehensively using topological optimization, parameter optimization combined with pre-stress modal analysis and frequency response analysis is proposed. Taking a typical vibration test fixture as an example, the basic shape of fixture structure is obtained by topological optimization, and the interface location between the fixture and the vibration table is adjusted by parameter optimization according to the actual working conditions and design principles. While the mass of the optimized fixture is reduced by 32.65%, the natural frequency and the quality factor of the response point did not deteriorate significantly and the vibration transmission characteristics meet the design requirements. Through the physical random tests, the power spectral density response curve of the test point is basically consistent with the acceleration amplitude-frequency curve of the simulation response point, which proves the accuracy of the finite element model and the effectiveness of the comprehensive optimization design, and provides references for the subsequent design of the vibration test fixture for missile-borne electronics.

Fragments,as the primary damage elements of blast-fragmentation warhead,have their damage lethality which is quantitatively evaluated through precise testing of parameters such as fragment velocity,spatial distribution and mass characteristics.This paper systematically reviews the latest advancements in the parameter testing technologies for the fragment fields of blast-fragmentation warheads,focusing on comparative analysis under two typical conditions of static and dynamic detonations.In the context of static detonation testing,the principles and features of the contact-type technologies such as net targets,the sectional optoelectronic technologies of light curtains and radar and the 3D reconstruction technologies like high-speed stereovision are compared in detail,and their technological improvements and development trends are elaborated.In the context of dynamic detonation testing,the research achievements in testing methods and simulation modeling at home and abroad are reviewed,and the unique challenges such as detonation point control and spatiotemporal synchronizationunder dynamic detonation conditions as well as the corresponding solutions are thoroughly analyzed.Furthermore,this paper also explores the applications and enabling potential of intelligent algorithms represented by machine learning (particularly deep learning) in the aspects fragment target recognition,trajectory tracking,data fusion,and dynamic explosion parameter prediction.Finally,it offers prospects for the future development trends in fragment field parameter testing technologies,and proposes the need to prioritize high-precision dynamic detonation fragment parameter testing technologies,enhance the 3D reconstruction capabilities and strengthen the integration of machine learning in testing methodologies,thereby supporting the optimized design and damage effectiveness evaluation of blast-fragmentation warheads.

The super caliber canard-controlled projectiles have a large front diameter,a forward center of gravity,a variable diameter cross section in the middle of the projectile body,and more complex surface gas flow.In order to study its aerodynamic characteristics,the lifting resistance characteristics,pitching moment characteristics and the surface flow field distribution of the projectile were analyzed by numerical calculation.The results show that the lift-drag ratio increases first and then decreases with the increase of attack angle,and the lift-drag ratio reaches the maximum when the attack angle is 8°.The pitch moment provided by different parts of the projectile body is studied in different areas.It is found that the forward pitch moment provided by the projectile tail takes up more than 30% of the total pitch moment when the attack angle α=0°,elevator angle δ_z=5°,and the stability ratio of the δ_z=10° decreases by 46.8% compared with δ_z=5°.Vortices appear at the variable diameter of the projectile body,which interact with the vortices of the rudder surface and the vortices around the surface of the projectile body,making the gas flow on the surface of the projectile body more complicated and increasing the difficulty of control.

In order to study the effect of heat insulation coating structure on the thermal protection performance of fuzes in different thermal environments,the typical large-caliber grenade fuze of JHX-1 charge was taken as the research object,and the slow burning and fast burning simulation of fuzes with no heat insulation coating structure,single heat insulation coating structure and composite heat insulation coating structure were carried out.The simulation results show that the design of the thermal insulation coating structure can prolong the response time of the fuze under both fast and slow burning conditions,and the delay effect is the most obvious in the fast burning environment,the delay effect is 69.1%.Under the same thermal environment and the same thickness of the overall thermal insulation coating of the fuze,the delay effect of the single-coating thermal insulation structure on the response time is better than that of the composite coating thermal insulation structure,and the thermal protection performance is the best when the shell is coated with flame retardant thermal insulation material,and the delay effect is 51.6% under the fast burning ring.According to the comprehensive analysis,the inner/outer composite thermal insulation coating structure can be considered for the fuze body with limited coating thickness,and the thermal protection effect of the composite coating structure can be improved by increasing the coating thickness of the outer material on the basis of meeting the functional requirements of the fuze.

To optimize the aerodynamic shape of small-caliber super-high-speed armor-piercing projectiles, a research on the influence of the shape parameters of the armor-piercing projectiles on the aerodynamic characteristics and flight stability was conducted. Based on three key factors, namely the sweepback angle of the tail fins, the aspect ratio, and the overall length-to-diameter ratio of the entire projectile, multiple improvement schemes for the aerodynamic shape were put forward. A numerical calculation model of the hypersonic flow field was established by using Fluent to explore the variation patterns of the aerodynamic parameters and flight stability. Through comparative analysis, the superior aerodynamic shape scheme was acquired. The results suggest that the zero-lift drag coefficient is reduced by 5.3%~26.9% after the improvement, and the lift coefficient and static moment coefficient are better than those of the original projectile. The static stability reserve amounts to 11%~29%, and the logarithmic attenuation rate of the amplitude ε equals 34.39%, meeting the stability requirements of tail-fin-stabilized armor-piercing projectiles. Meanwhile, the firing altitude, velocity drop, and oblique range at each firing angle have witnessed significant improvements compared to the original projectile. This offers a certain reference for the shape optimization design of small-caliber super-high-speed sabot-armor-piercing projectiles.

To address the issue that traditional UAV obstacle-avoidance algorithms have low efficiency in unknown and complex environments,an improved improved Dynamic Window Approach (DWA) fusion algorithm was proposed.Regarding the lack of a global perspective in the DWA algorithm,a bidirectional search strategy was introduced to enhance the global value of the planned trajectory.Confronted with the difficulty of balancing calculation speed and accuracy in the DWA algorithm,a dynamic time step adjusted according to the environment was designed to weigh the computational efficiency.Aiming at the poor environmental adaptability of the DWA algorithm,a trajectory evaluation function with variable weights was put forward to improve environmental fitness.To boost the inter-UAV obstacle-avoidance ability in the multi-UAV collaborative mode,the improved DWA algorithm was integrated with the with the ORCA (Optimal Reciprocal Collision Avoidance) method.Simulation experiments were conducted to verify the proposed improved fusion algorithm.Compared with the traditional DWA algorithm,the UAV flight trajectory has decreased by 33.10%,the mission completion time has been shortened by 31.32%,and the number of iterations has been reduced by 50.05%.The overall performance has been significantly enhanced,which holds guiding significance for the engineering application of multi-UAV autonomous obstacle-avoidance technology.

Considering the coexistence of both matched and unmatched unknown disturbances in electro-hydraulic valve-controlled erection systems and the inherent dead-zone nonlinearity in hydraulic valves, a novel nonlinear controller is proposed. First, a nonlinear mathematical model of the electro-hydraulic erection system is established based on the electromechanical-hydraulic coupled dynamics of the system and the dead-zone characteristics of the hydraulic valve. Second, based on the full-state feedback condition, the aforementioned mathematical model is reformulated, and an adaptive extended state observer (AESO) along with a disturbance observer (DO) is designed to estimate both matched and unmatched disturbances, and effectively suppress the observation peaking phenomenon. Third, a novel active disturbance rejection controller is developed leveraging the aforementioned AESO and DO to achieve feedforward compensation for disturbances. Simultaneously, to address the inherent "differential explosion" issue in the conventional backstepping-based controller design framework, a nonlinear command filter is incorporated. At last, through rigorous analysis based on Lyapunov's theory, it demonstrates the boundedness of the motion errors of the system, observer estimation errors and filter error, and verifies the stability of the controller. A simulation platform is developed to validate the performance of the proposed controller. Comparative results with conventional industrial PID controller demonstrate that the proposed controller significantly enhances motion tracking accuracy of the electro-hydraulic erection system.

To investigate the impact of rocket engine gas jet on front cover of a multi-launcher canister during a rocket launching process, a numerical simulation approach was adopted to analyze the flow field after the rocket exits the canister. A gas jet impingement model was established based on the 3D compressible Navier-Stokes equations, the Realizable k-ε turbulence model, and a second-order upwind total variation diminishing (TVD) discretization scheme. The results reveal that as the canister-out height of the rocket increase, the impingement effects on the canister initially intensify and then diminish. Key findings include: At 0.5 m out height, the front cover bears the lowest surface temperature and lowest pressure, with minimum impact loads. At 8 m height, the front cover bears the highest peak temperature of 1 375 K and highest maximum pressure of 195 kPa. At 10 m height, the impact load peaked at 20.21 kN, followed by a gradual reduction in temperature, pressure, and impact loads as the rocket ascended further. This study provides critical insights for safety design of launcher canisters and thermal protection strategies for launch systems.

In order to support the selection of materials for the combustion chamber shell of solid rocket motor, an evaluation model for the effective volume, mass, mass ratio, and PV/W coefficient of the cylinder section is established based on thickness. Based on 30CrSiNiMoVA, the variation of the structural characteristics of the cylindrical shell under typical metal and non-metallic material conditions could be obtained through non quantitative derivation analysis and a fast lateral analogy method for the comprehensive benefits of typical material shells is proposed. The results indicate that when calculating various structural features, both metallic and non-metallic materials can be equivalent to the same structural form calculation formula. With the increase of pressure, the change of effective volume and mass ratio of cylinder section caused by material replacement is larger and linear,but it has little effect on the change of mass and volumetric efficiency coefficient of cylinder section; Without considering the material craftsmanship and comparing with metal materials,the use of titanium alloy and fiber materials has advantages in improving the comprehensive performance of the shell,and the advantages of fiber materials are more obvious. When using conventional aluminum alloys, it does not have advantages.

Addressing the control problem of coordinated formation control of leader-follower aircraft, we put forward a missile formation flight controller design method that take the leader aircraft as a virtual target and the missiles fly in formation according to leader's ballistic coordinate system. Firstly, define a relative motion coordinate system in the inertial coordinate frame to establish a relative motion model, which is then transformed into the leader missile's ballistic coordinate system. Secondly, take the position of the follower missile in the line-of-sight coordinate system and the velocity of the leader missile in the inertial coordinate system as state variables and take the acceleration of the follower missile as the control input and then integrate the error between the follower missile's relative position and its desired position, along with the velocity error of the leader missile to design a formation controller using sliding mode variable structure control theory. Finally, simulate and validate a formation structure comprising one leader missile and two follower missiles. Simulation results demonstrate that the proposed method can rapidly and accurately construct and maintain the desired formation.

For the flight control of quadrotor unmanned aerial vehicles (UAVs) affected by multi-source disturbance,a self-tuning sliding mode flight control algorithm based on multi-source disturbance compensation and hierarchical sliding mode control is proposed.The quadrotor UAV system is divided into a two-degrees-of-freedom dual-input fully-actuated subsystem and a four-degrees-of-freedom dual-input underactuated subsystem,based on which the sliding variable of the fully-actuated subsystem is defined.A sliding variable construction method for hierarchical sliding mode controller is proposed,and the sliding variable of the underactuated subsystem is designed by adopting this method.A generalized Super-Twisting disturbance approximator is designed to observe the multi-source disturbance,and a fuzzy compensator is designed to compensate for the approximation error of the disturbance approximator.A reaching gain self-tuning sliding mode controller is designed by utilizing the combined power reaching law,and the disturbance approximator with fuzzy compensator is used to suppress the influence of the multi-source disturbance.The roles of the core modules in the proposed control algorithm are analyzed,and the proposed control algorithm is compared with the existing control algorithms.The comparison results show that the proposed control algorithm has good multi-source disturbance rejection ability,and can also provide superior dynamic control performance.

A low-sidelobe array pattern design method utilizing fmincon is proposed based on MATLAB.The array beam optimization problem is transformed into a nonlinear constrained optimization problem with continuous variables by constructing a hybrid penalty cost function with the objective of minimizing the sidelobe level in the target region and utilizing the nonlinear constraints for controlling the gain fluctuation of mainlobe.Numerical results demonstrate that The designed array can achieve a suppression of 15-20dB sidelobe level within specified spatial regions while ensuring that the gain fluctuation of mainlobe is less than 0.3dB.And the optimization process exhibits rapid convergence and excellent stability.The proposed method gives consideration to optimization precision and computational efficiency.It provides a high-performance and high-reliability solution for antenna array designs requiring the mainlobe shaping and sidelobe suppression in specific region,has significant engineering practical value.

With the rapid development of economic construction in rocket wreckage landing zone, the number of high-value targets on the ground in the landing area is gradually increasing, and the harm and risk control difficulty caused by rocket wreckage falling are becoming increasingly difficult, the demand for accurate tracking, measurement, accurate positioning and rapid recovery of rocket wreckage is becoming more and more urgent. Through the analysis of ballistic characteristics of rocket wreckage flight trajectory, a prediction model is established. The model is compared and analyzed based on measured data of the controlled recovery test of the wreckage parachute, and the appropriate correction and optimization are carried out accordingly. The optimized model is verified and analyzed by the measured data of another test. The results showed that the predicted trajectory had a high degree of agreement with the measured data, with a maximum spatial distance error of about 5.1 km. The prediction accuracy is improved by about 1 times, and the model design is reasonable, applicable and effective, with high accuracy. It can provide accurate real-time data guidance for rocket wreckage tracking and measurement equipment, and provide ideal prediction data for precise positioning and rapid recovery of wreckage, effectively improving the efficiency of landing area work.

To address the challenge that the frequency-agile radars in the stable tracking phase in modern complex electromagnetic environments struggle have difficulty in balancing both coherent integration gain and anti-jamming capability under blanket jamming,this paper proposes a joint control method for frequency and dwell time based on proximal policy optimization (PPO).Firstly,the trade-off relationship between radar coherent integration gain and intercept risk is analyzed.The dynamic combined jamming behavior of jammers is modeled,and a Markov decision process model for radar anti-jamming,incorporating signal-level feature feedback,is constructed.Secondly,the PPO algorithm is introduced.A compound reward function that takes into account both detection performance and survivability is designed,enabling the radar agent to autonomously learn the optimal strategy in unknown dynamical adversarial environments.This strategy can adjust the operating frequency and dwell time in real-time based on environmental feedback to maximize the signal-to-interference-plus-noise ratio.Simulated results demonstrate that,compared to traditional strategies,the proposed strategy can effectively evade the combined blanket jamming.It significantly reduces the probability of being jammed while substantially improving the output SINR,exhibiting strong environmental adaptability and robustness.

The shaped charge is widely used in the field of unexploded ordnance destruction disposal due to its high energy utilization rate.For the safe and effective disposal of unexploded ordnance in water,this paper investigates the factors influencing on the underwater initiation capability of jets.Numerical simulation methods are employed to characterize the jet formation process of two charge structures in water.Focusing on the flared liner shaped charge structure,the effects of the charge structure,the length of the combined cavity structure at the head,and the water depth on the initiation capability of the shaped charge jet are analyzed.The results indicate that the flared liner charge structure affects the jet’s initiation capability in the following order of significance:liner height,liner thickness,explosive column height,and liner curvature.The combined cavity structure significantly reduces the energy loss of the jet by 74.8%.The Random Forest (RF) model effectively predicts the nonlinear variation characteristics of the contact velocity between jet and shelled charges in water with the increase in water depth.

The three-axis seeker of loitering missile faces the technical problems of single optical axis pointing mapping multiple frame angle combinations and fast real-time calculation of optimal instructions when tracking the target. Based on the kinematics analysis of the three-axis seeker, an adaptive fast tracking strategy for the three-axis seeker is proposed. The influence of the combination of three-axis bandwidth and three-axis increment on the tracking speed of the seeker is analyzed, and the fitness function evaluation standard with frame adaptability is established. The simulation results show that the proposed strategy can solve the optimal tracking instruction under the framework constraint, solve the problem that the tracking instruction cannot be tracked due to exceeding the mechanical limit, and realize the tracking target of the control optical axis along the optimal path. The average iteration time is 3.54 ms, and the tracking speed is improved by 30.4%.

Under the current conditions of air combat confrontation,targets often behave medium and large overloads and strong maneuvers,and it is difficult to predict the trajectory of maneuver.In order to solve the problems of low prediction accuracy and short prediction time of the traditional trajectory prediction methods,a multi-step trajectory prediction method based on Bayesian optimization hyperparameters in bidirectional long short-term memory network (BO-Bi-LSTM)is proposed in this paper.The sliding prediction method is analyzed,and an online rolling prediction mathematical model is established to solve the problem of prediction value construction.The network hyperparameters are optimized automatically by using Bayesian optimization method,and the optimal hyperparameters are obtained after iteration several times.The length of the sliding window is analyzed,and the length of the sliding window with the highest prediction accuracy is obtained among the classical sliding window length.In order to test the prediction performance of this method on the maneuvering trajectory,a classical maneuvering flight trajectory is predicted and simulated in this paper,and compared with three other neural network prediction models,the simulation results prove that the bidirectional long and short time domain memory network multi-step prediction method with Bayesian optimization hyperparameters is higher in prediction accuracy than the other three neural networks.The accuracy of the 3D trajectory error is less than 200m,which can be predicted continuously for about 4.5s.

The performance of signal acquisition in satellite navigation receivers is significantly influenced by the setting of detection thresholds.The existing methods are difficult to to adapt to the increasingly complex electromagnetic environments in urban areas,where they are prone to generate false alarms under multiple interference conditions,severely affecting acquisition reliability.To address this issue,a constant false alarm rate (CFAR) detection technique is incorporated into the acquisition of BeiDou B1C signals.An algorithm that dynamically adjusts the decision threshold based on the estimated number of interference targets is proposed.This algorithm adaptively determines the decision threshold of signal acquisition according to the real-time estimated number of interference targets in the environment,thereby enhancing the performance of receiver in multi-interference environment.Simulated results demonstrate that the proposed algorithm significantly improves the robustness and acquisition sensitivity of the receiver in complex interference environments,thereby increasing the operational reliability of military equipment in urban warfare.

Aiming at the problem of insufficient matching accuracy and even divergence caused by initial errors in inertial navigation and gravity measurement errors in traditional nearest contour iteration (ICCP) algorithm,an improved ICCP algorithm is proposed to improve matching accuracy and reliability.Firstly,two assumptions affecting the matching accuracy of traditional ICCP algorithms were analyzed,and the estimated path was limited to the vicinity of the INS path by introducing a total constraint error; On this basis,rough matching is constructed using MAD and MSD matching rules,and the obtained rough matching path is used to replace the INS measurement path in subsequent accurate matching.Then,the ICCP algorithm is used for fine matching to achieve higher positioning accuracy; Establish a Kalman filter model by taking the difference between the output position of the inertial navigation system and the matching position of the ICCP algorithm as the observation vector of the filter,and correct the errors of the inertial navigation system.The simulation and analysis results show that,considering the initial errors of inertial navigation and gravity measurement errors,the improved ICCP algorithm has a maximum attitude error of less than 0.015 °,heading error of less than 0.4 °,and maximum position error of less than 30m.The navigation accuracy is improved by more than 70% compared to the traditional ICCP algorithm,effectively improving the positioning accuracy of the inertial/gravity gradient integrated navigation system.

To address the issue of aeroelastic instability in fuze turbine generators under wide-Mach-number and high-rotational-speed conditions,the deformation characteristics of blades and their impact on the aerodynamic torque are investigated using a sequential fluid-structure coupling method.The decoupling analysis of the loads reveals that the predominant cause of blade deformation is the high-speed centrifugal load,accounting for over 98% of the total deformation,rather than the aerodynamic load.The research demonstrates that this centrifugal-induced deformation leads to the significant geometric distortion of the blades,compromising the original aerodynamic profile.Consequently,the driving torque of turbine generator declines gradiently as the rotational speed increases.The torque is reduced by approximately 26.6% at the maximum rotational speed.The results reveal the underlying mechanism of the flexible blade deformation affecting the performance of fuze turbine generator,providing a theoretical foundation for the robust design of fuze power supplies.

The IMU’s internal temperature continuously rises with the working time,resulting in changes of the inertial sensors’ zero bias and scale factors.Especially after the miniaturization design of the IMU,its internal temperature environment field becomes more complex.The outputs of IMU’s gyros and quartz accelerometers are obviously affected by temperature changes,which restrict their application in navigation systems.The IMU’s acceleration channel is mainly composed of accelerometers and analog-to-digital conversion circuit.The analog-to-digital conversion circuit’s performance level directly affects the IMU’s accuracy.This paper proposes a temperature compensation method of the acceleration channel.Firstly,establishing the temperature model between the own output of the analog-to-digital conversion circuit when there is no input current and the inertial temperature of IMU to compensate for the own output of the circuit.Secondly,compensating the outputs when the acceleration channel is connected.The effects of the temperature differences are avoided when the analog-to-digital conversion circuit is independently compensated which affects the compensation accuracy.The model of acceleration channel variation with temperature is established more precisely,and the temperature compensation accuracy of acceleration channel is improved.Taking an IMU for example,the zero temperature repeatability of acceleration channel is increased to 2-10 times and the scale factor temperature repeatability is increased to 2-3 times,the validity and reliability of the temperature compensation method are verified by experiments,thus improving the working accuracy of the miniaturized IMU in the whole working temperature range.

The evaluation of aviation weaponry’s combat capability is not merely a technical matter,but also a strategic one.It directly determines whether the equipment can fulfill its intended operational roles on the battlefield and whether future warfare patterns can be accurately predicted.To address the inherent limitations of traditional evaluation methods—including such as over-reliance on expert experience,insufficient persuasiveness of evaluation models,and difficulties in indicator acquisition,this paper proposes a combat capability evaluation approach for aviation weaponry based on Uncertainty Structural Equation Modeling (USEM).Specifically,Triangular Fuzzy Number (TFN) and Deep Neural Networks (DNN) are both integrated to process collected simulation data,aiming to mitigate the drawbacks of limited data availability and significant subjectivity in expert-derived data,thereby enhancing modeling accuracy.The combat capability indicator values processed via the triangular fuzzy number algorithm are converted into SPSS-compatible files,and imported into AMOS for analysis,enabling the establishment of correlations between the combat capability index values and the structural equation model.The results demonstrate that the CN value ranges from 0 to 3,and the RMSEA value is less than 0.08,The CFI and TLI values are both greater than 0.9,all indicating excellent model fit.Furthermore,the model’s estimated values align with the actual missile combat capability indicators,verifying its validity for evaluating the combat capability of aviation weapons and equipment.

Manual assembly of aero-engine casings with dissimilar flanges suffers from low efficiency,poor mating accuracy and high safety risk.To overcome these problems,this paper proposes a compliant control scheme for a six-degree-of-freedom Stewart platform that learns to insert a flange test specimen via reinforcement learning.Firstly,the kinematic and dynamic models of the Stewart platform are established,and its ability to adjust posture under complex constraints is analyzed.Secondly,a data-driven compliant strategy that fuses admittance control with a reinforcement-learning algorithm is designed to realize high-precision mating and gentle insertion.Finally,a co-simulation framework combining Webots and PyCharm is built to verify the effectiveness and robustness of the proposed method under various initial misalignments and disturbances.Results show that,compared with traditional fixed parameter admittance control methods,the proposed method reduces the maximum contact force of the platform by 30.4% and improves the assembly efficiency by about 90% during the assembly process,and achieves a steady-state position error of only 7.5mm.This indicates that the proposed method significantly improves work efficiency and accuracy while ensuring assembly safety,and has good engineering promotion value.

To address the challenge of intercepting high-speed maneuvering targets with anti-aircraft missiles,a three-dimensional terminal guidance law that considers the constraints of the terminal line-of-sight angle is proposed.Initially,an adaptive estimation model for target acceleration is established,based on the three-dimensional relative motion model between the missile and its target.This model effectively tracks the line-of-sight angular velocity and achieves high-precision estimation of the target’s maneuver acceleration.Following this,the formula for converting the terminal line-of-sight angle constraints from the ground coordinate to the missile coordinate is derived.Subsequently,a terminal guidance law that is capable of directly utilizing the missile’s seeker measurement information is designed,by integrating sliding mode variable structure control with finite-time convergence theory.It is rigorously proven through mathematical derivations that the proposed guidance law ensures the stability and finite-time convergence of the guidance system’s state variables.Lastly,a digital simulation validation is conducted to evaluate the designed terminal guidance law.The results demonstrate that it not only effectively controls the line-of-sight angle to attain the targeted value but also significantly reduces the missile’s mean miss distance to within 1 meter.Compared to the conventional biased proportional navigation law,it notably decreases the required terminal overload and enhances the missile’s guidance accuracy.Furthermore,by directly incorporating seeker measurement information,the proposed guidance law contributes to simplifying the complexity of the guidance system,offering significant reference and application value for advancing research in air defense missile guidance technology.

To improve the prediction efficiency of the impact point of small-caliber bullets, this paper proposes a rapid prediction method for the bullet impact point based on the Multilayer Perceptron (MLP). The method achieves an efficient mapping from the initial conditions of the projectile to the muzzle attitude of the projectile through the MLP, and combines a six-degree-of-freedom external ballistic model to calculate the projectile’s landing position at 300 meters. The MLP is trained with a dataset from finite element calculations of the projectile’s muzzle attitude, and compares the calculation accuracy and efficiency of the MLP-based method with the traditional finite element calculation method. The results show that the prediction results based on the MLP are essentially consistent with the calculation results of the finite element model, but the calculation time is significantly reduced. Under the same hardware configuration, the MLP model reduces the calculation time from 673.1 minutes of the finite element model to 9 minutes. This method significantly improves the calculation efficiency while ensuring accuracy, providing a new approach for rapidly predicting ballistic accuracy and improving the utilization of computing resources.