In order to investigate the blast resistance of a 316L stainless steel honeycomb sandwich structure, a honeycomb sandwich structure was designed and fabricated using 316L stainless steel powder by selective laser melting (SLM). Concurrently, solid panels of equivalent surface density were produced by this method and constituted the control group. The mechanical behavior of the structure under near-field static explosion load is obtained through static explosion experiments and LS-DYNA simulation experiments, and the propagation mode of the stress wave within it is investigated in order to elucidate the underlying anti-explosion principle. Moreover, optistruct is utilized to optimize the topology and structure of the structure, with the objective of enhancing its blast resistance. The findings indicate that the backplate deflection of the porous sandwich structure is diminished by 13.2% in comparison to that of the plate with isoplanar density, thereby enhancing blast resistance. The established numerical model of fluid-solid coupling is capable of describing the three phases of the static explosion experiment, namely the shock wave propagation phase, the fluid-solid coupling phase, and the inertia phase. The explosion experiment yielded definitive results at the center of the target plate, thereby demonstrating that the "川" crack is caused by residual core layer extrusion. Moreover, the core layer deformation failure mechanism for the honeycomb panel was observed to manifest as in-plane stretching and tearing. The optistruct optimization results demonstrate the formation of a triangular skeleton and circular holes, alternating with corrugated plates. The structure, optimized for a corrugated core target plate, displays enhanced resilience in comparison to the optimization of a traditional honeycomb sandwich panel. The explosion load backboard deflection exhibited a 25.4% reduction, the peak pressure behind the plate demonstrated a 17.6% reduction, and the blast resistance was significantly enhanced. In comparison to honeycomb panels, the circular hole structure has been demonstrated to reduce the backplane deflection by 38.1%, while the triangular hole structure has been shown to reduce the peak pressure behind the plate by 22.4%.

During the transfer alignment under moving base, the flexible deformation between the master and slave inertial navigation systems (INSs) is the primary error factor affecting the alignment accuracy of the slave INS. In traditional transfer alignment methods, flexible deformation is usually equated to empirical Markov models. However, a low match between actual flexible deformation and the empirical model can lead to a decrease in transfer alignment accuracy. Therefore, a high-accuracy transfer alignment method without relying on empirical model of flexible deformation is proposed. Firstly, the intrinsic relationship between the flexible deformation and the angular velocities measured by master/slave gyroscopes is derived and established. Thus, the rough value of flexible deformation is directly calculated using the measured angular velocities. Then, the coupling relationship between the calculation error of flexible deformation and the gyroscope error is derived, and a novel transfer alignment system model that does not rely on empirical models of flexible deformation is established. Furthermore, the optimal estimation algorithm is used to accurately estimate and correct the calculation error of flexible deformation. Simulation results show that the proposed method can accurately compensate the complex flexible deformation, thereby achieving high-accuracy transfer alignment under moving base.

The active sidestick is a crucial control device that can adjust the flight attitude of an aircraft. In the automatic flight mode, the active sidestick follow-up function tracks the control commands from the flight controller in real-time to enhance the pilot's perception of the aircraft's flight status, thereby effectively improving flight safety. However, unknown disturbance torques in the system can degrade the tracking accuracy of the active sidestick. To address this challenge, a control method based on composite nonlinear feedback and adaptive integral sliding mode is proposed for the follow-up control of the active sidestick. This method integrates an integral sliding mode control algorithm and the composite nonlinear feedback control algorithm, where the composite nonlinear feedback control effectively improves the steady-state performance of the active sidestick system, and the adaptive integral sliding mode control effectively restrains unknown system disturbances. Extensive experimental results show that the proposed improved active sidestick follow-up control algorithm can reduce the adjustment time by approximately 41% and the steady-state error by about 93.6% compared to the previous composite nonlinear feedback control algorithm. Furthermore, under disturbance conditions, the improved follow-up control algorithm can reduce the adjustment time by about 79% compared to the traditional PID algorithm. This demonstrates that the designed improved active sidestick follow-up control algorithm can significantly enhance the system's control accuracy and response performance, and possess excellent disturbance rejection capabilities.

In order to investigate the influence of liner structure parameters on the formation of jet penetration charge (JPC) as well as the penetration ability and post-effect action of the formed JPC on ceramic composite target plates, this study adopts orthogonal experimental optimization to design the structure parameters of an equal-wall-thickness conical liner. The LS-DYNA software is utilized to conduct research on how warhead structure parameters (cone angle, thickness, length-to-diameter ratio) affect the characteristic parameters of JPC damage elements. Through range analysis, the combination of structure parameters that results in better JPC formation performance is obtained. Based on the optimized structure, the damage situation of JPC damage elements on composite targets is studied. The results showed that when the liner cone angle is 90°, the wall thickness is 2.5 mm, and the charge length-to-diameter ratio is 0.9, the penetration effect is better. At this time, the funnel pit diameter increased by 8.93%, the funnel pit depth increased by 3.7%, the average diameter of the hole increased by 8.29%, and the total penetration thickness increased by 9.88% after removing the target plate spacing. This research can provide a theoretical and technical basis for the design of rod-shaped jet liner structure parameters and for studying the penetration ability on ceramic composite target plates.

To address the issue of hit accuracy of terminal guidance phase of a rotor loitering terminal sensitive projectile, that is jointly affected by detection system errors and attitude disturbances, this study focuses on the dynamic factors which affect the dispersion of EFP warhead destruction element. In the study, a dynamic impact point model is established based on the seeker system detection error, airframe's spatial attitude disturbances, implicated motion deviation of the warhead destruction element and system latency, meanwhile the trajectory of missile target rendezvous and swinging attitude correction in the final guidance phase are utilized. By taking full advantage of airframe's attitude information and with the help of experimental flight data, the model can be used to analyze the influence of each factor on the point of impact. Simulation and analysis results demonstrate that, under certain random disturbances, the primary factor causing aiming error is the airframe's attitude disturbances and rendezvous trajectory deviation, so that gain the attitude angle control requirements necessary to achieve a desired hit rate on a typical armored target. This study provides a theoretical basis for the research on guidance law and trajectory prediction control of loitering terminal sensitive projectile.

To investigate the damage effectiveness of low, slow and small Unmanned Aerial Vehicles(UAVs) under fragmentation strikes, an evaluation model is established to comprehensively assess the damage effectiveness of fragments against UAVs. Numerical simulations are conducted to analyze the damage probability of a single fragment impacting various UAV compartments under different initial velocities, diameters, and material conditions, followed by extensive shooting simulations using the Monte Carlo method, with thousands of iterations to ensure statistical robustness. The results indicate that the initial velocity, diameter, and material of the fragment significantly influence the damage probability. An increase in initial velocity and diameter notably enhances the damage probability; however, the effectiveness tends to saturate within the velocity range of 900~1 500 m/s and diameter range of 4~8 mm, showing diminishing returns beyond these thresholds. The use of multiple fragments significantly increases the damage probability, suggesting that an increase in the number of fragments leads to a substantial improvement in damage effectiveness, making the quantity of fragments a crucial factor in determining the overall damage outcomes. Based on these findings, selecting fragment diameters between 2 mm and 4 mm, initial velocities between 600 m/s and 900 m/s, and appropriate materials can optimize the design of fragmentation warheads, thereby significantly enhancing their damage effectiveness against UAVs. This study provides a scientific basis for the precise evaluation of UAV damage effectiveness, offering valuable insights for the development of more effective countermeasures and supporting informed decision-making in combat scenarios to ensure enhanced operational effectiveness and strategic advantages.

This article proposes a heading calculation and integrated navigation algorithm based on continuous matching, which realizes the use of small field of view guided cameras to calculate the heading and provides a low-cost heading measurement and integrated navigation solution for unmanned aerial vehicles. The algorithm first calculates the attitude increment based on the essential matrix obtained from continuous matching, and further calculates the heading angle of the current frame through the first frame attitude matrix and joint calibration matrix. Based on this, a fusion algorithm for MEMS navigation solution and visual continuous matching is designed based on inertial navigation attitude filtering. To verify the accuracy and computational efficiency of the algorithm proposed in this paper, an inertial/visual combination device and a captive flight experimental system are constructed. The flight experiment results show that for cameras with a pixel count of 1 920×1 080, the matching success rate reaches 99.6% during flight at an altitude of 80~200 m. The heading calculation accuracy is better than 0.21° and the update frequency is better than 20 Hz during half hour navigation. Compared with traditional methods, it has a higher matching success rate, heading calculation accuracy, and lower time consumption.

Heterogeneous scene matching, as an important auxiliary navigation method, has been widely studied. However, due to the influence of nonlinear radiation distortion and geometric deformation between heterogeneous image pairs, achieving heterogeneous image matching remains a challenging task. To address these issues, a heterogeneous scene matching method with rotation and scale invariance is proposed to simultaneously estimate the rotation, scale, and displacement variations between heterogeneous image pairs. Firstly, based on the local structural relationships of the image, local self-similarity descriptors (LSS) are used for feature description to resist the influence of nonlinear radiation differences and local deformations. Combined with the logarithmic polar coordinate transformation, the overall rotation and scale changes of the image are orthogonally expanded and represented separately in the Cartesian coordinate system. Finally, by utilizing the continuity of displacement estimation, rotation, and scale estimation, a five-dimensional feature descriptor is constructed and using phase correlation method estimates the variation of image rotation, scale and displacement simultaneously. Experiments conducted on three common types of heterogeneous image matching tasks shows that the proposed method achieves a matching accuracy of at least 4.5% higher than existing state-of-the-art methods tech, that highlights its effectiveness in the field of heterogeneous scene matching.

Because of low cost and flexible operation mode, more and more loitering munitions have been used in local conflicts worldwide in recent years, which has attracted wide attention. This paper introduces the development status of main foreign loitering munitions in the world, involving products of the United States, Israel and other military powers which include the Switchblade series, Coyote series, KUB-BLA series, Lancet series, Harop and Hero series of loitering munitions. Based on the introduction, the paper provides analysis of the development status of foreign loitering munitions, and puts forward the future development trend in the aspects of low cost, serialization, multi-platform delivery, stealth development and swarming operation.

This study commences with an examination of the operational sequence of the secondary fuze in a fuel-air explosive (FAE) munition, analyzing the potential interference factors such as shock waves and electromagnetic radiation, as well as their characteristics, that the secondary fuze may encounter at the terminal phase of the trajectory. Counter-interference design methods for the secondary fuze are proposed from various perspectives, including trajectory design, circuit design, and structural design. Static detonation experiments were conducted to compare the interference-resistance capabilities of the secondary fuze under two different configurations: independent design and cable-connected design. The experimental results indicate that the secondary fuze with an independent structural design exhibits superior interference-resistance, capable of emitting a normal ignition signal at the preset timing following the explosion of the dispersed charge. In contrast, the secondary fuze with a cable-connected design failed to issue an ignition command at the designated moment, resulting in electrical failure of the components within the fuze. It is postulated that the electromagnetic radiation generated by the detonation of the explosive charge enters the fuze through field-line coupling, thereby causing damage to the fuze. Furthermore, the experimental results demonstrate that under the conditions of this study, the pulse interference current induced has a duration reaching the order of hundreds of nanoseconds, with a peak current reaching tens of amperes, which is sufficient to directly inflict damage on the microcontroller and interface circuits of the fuze.

In order to further enhance the damage capability of the explosively formed penetrator (EFP) warhead, a combination of theoretical analysis, numerical simulation, and experimental verification was employed to design a novel explosively formed arrow-shaped penetrator warhead. The formation effect of the explosively formed arrow-shaped penetrator was controlled by adjusting the number of linearly arranged explosive liners, thereby increasing the damage power of the damage element. Initially, theoretical analysis was conducted to establish a physical model, determining the number of liner arrangements. Subsequently, numerical simulations were performed to validate the feasibility of the designed scheme. A warhead with 12 columns of linearly arranged liners was then fabricated and subjected to static detonation experiments. The experimental results demonstrated that a single liner could form two explosively formed arrow-shaped penetrators, capable of penetrating a 30 mm-thick Q235 steel plate at a distance of 5 m. The research findings indicate that the principle of forming explosively formed arrow-shaped penetrators from linear liners is viable and holds significant implications for the design of EFP warheads.

Dynamic explosion point localization constitutes a pivotal element in damage assessment. The explosive sound wave, originating from the attenuation of a shock wave, is characterized by supersonic velocity and a defined sphere of influence. Accordingly, the accuracy of explosion point acoustic localization is susceptible to the influence of the explosive shock wave. To explore the impact of the explosive shock wave segment on the acoustic localization outcomes during the explosion point localization process, a wave arrival time-distance model for the attenuation of the shock wave into a sound wave was constructed, predicated on the pressure attenuation law of the explosive shock wave. This model was subsequently integrated into the localization methodology based on the time difference of arrival (TDOA). Utilizing a prototypical arrangement as a case study, the preset explosion point and the acoustic sensor array's position were delineated, and the corresponding wave arrival times were computed. The TDOA-based localization approach was employed to retrodict the position of the explosion point relative to the acoustic sensor array, and the acoustic localization error of the explosion point was ascertained by juxtaposing the retrodicted position with the preset position. Furthermore, by modulating the preset explosion point position and the charge mass, the influence of the explosive shock wave on the acoustic localization error was scrutinized. The research findings suggest that the charge mass and the distance from the explosion center are the predominant factors influencing the localization error. As the scaled distance escalates, the localization error induced by the shock wave exhibits a diminishing trend. When the scaled distance surpasses 18.45, the relative distance error can be mitigated to below 1%. It is anticipated that these findings will serve as a reference for the systematic error correction of explosion point acoustic localization, thereby enhancing the computational precision of explosion point acoustic localization.

The influence of position effect and interface effect on the process of a tungsten alloy rod-shaped penetrator vertically penetrating a ceramic/aluminum alloy composite target plate is studied through experimental research and simulation analysis. The effect of the position effect on the protective performance of the target plate is examined by changing the impact point, while the effect of the interface effect on the protective performance of the target plate is investigated by varying the number of ceramic layers. Research on positional effects shows that when the impact point is within the range of 0 to 30 mm from the ceramic boundary, the penetration depth of the back-plane changes by 9 mm. When the impact point is within the range of 30 to 50 mm from the ceramic boundary, the penetration depth of the back-plane changes by 1 mm. It can be concluded that the protective performance of the target plate in this area is no longer influenced by the position of the impact point. In other words, the area that is greater than or equal to five times the bullet diameter from the ceramic boundary is the effective protection area of the target plate. Research on the interface effect indicates that the penetration depth of the composite target plate with three different structures at the same thickness is 40.32 mm, 47.47 mm, and 50.77 mm; that is, the ceramic protective performance decreases with the increase in the number of layers at the same thickness.

To meet the high control precision requirements of the resolver of advanced rotating modulation inertial navigation systems, and to address the limitations of traditional PI control in balancing dynamic response and steady-state error, a fuzzy-PI composite control method with saturation correction is designed. This method is arranged on the position loop of a traditional three-loop control system, taking the position error and the rate of change of position error as inputs. Configuring reasonable control strategies under different states, it can combine the advantages of both fuzzy control and PI control, and achieve precise system adjustment. Meanwhile, the incoming saturation correction technology can effectively suppress the excessive accumulation in the PI controller's integral term, so as to reduce the potential cumulative error during long-term operation and enhance system stability and control accuracy. This control method has been used on a certain model of gimbaled rotating inertial navigation device and performs well. The actual test results show that the steady-state accuracy of the system can be stably controlled within ±5″, and the response time can be controlled within 5 seconds, and it can meet the requirements of high-precision rotating position control.

At present, scholars carry out anti-missile damage assessment work basically simplifies the assessment model and assumes the derivation conditions, which has the problem of insufficient credibility. It is an effective means to enhance the credibility by injecting external fitted attitude information into the semi-physical system to reproduce the flight process of the missile, so as to carry out the damage assessment under the real ballistic rendezvous conditions. In this paper, firstly, the equations of motion of the missile model in the relative coordinate system of the target are given through the ballistic fitting of the semi-physical simulation system, and then according to the empirical formulas of the probability of the distribution of the guidance error, the probability of the distribution of the fuse activation zone and the probability of the destruction of the combat unit, combined with the semi-physical projectile-eye rendezvous conditions, the method of the determination of the integrated probability of the destruction is given. Finally, this paper carries out simulation calculations for specific examples, and analyzes the parameter characteristics and damage classifications of the simulation results. The results show that the relationship between the distance of the meeting and the azimuth angle of the fragmentation incident and the damage result, and the established damage evaluation table can predict the interception result of the interceptor to a certain extent, which can provide support and reference for the subsequent military operational decision-making.

In order to improve the penetration ability of multiple explosive formed projectile (MEFP) to armored targets, based on the design of end face MEFP, a combined end face ring double layer MEFP charging structure was constructed, which could form one main EFP and 24 auxiliary EFP in the circumferential direction, and could achieve multi-point damage to armored targets. ANSYS/LS-DYNA software was used to study the influence of the structural parameters of the cartridge cover on the molding effect and penetration performance of the MEFP warhead. The results show that when the wall thickness of the auxiliary cover increases, the projectile velocity of the auxiliary cover gradually decreases, the projectile dispersion angle of the middle auxiliary cover gradually decreases, and the projectile dispersion angle of the outer auxiliary cover gradually increases. When the radius of curvature of the auxiliary hood increases, the projectile velocity of the auxiliary hood gradually decreases, the angle of departure of the intermediate auxiliary hood gradually increases, and the angle of departure of the outer auxiliary hood gradually decreases. When the span of the auxiliary hood increases, the projectile velocity of the auxiliary hood gradually increases, the angle of dispersion of the intermediate auxiliary hood projectile decreases, and the angle of dispersion of the peripheral auxiliary hood projectile increases. The MEFP can penetrate 15 mm thick 45# steel target, thus effectively increasing the number of damage elements and damage area. The annular double layer MEFP structure of the end face combined charge structure has important reference significance for the warhead design of the terminal sensitive bomb.

In order to investigate the effect of combined liner structure on the damage performance of shaped charge warhead, the arbitrary Lagrange-Eulerian fluid-structure coupling algorithm based on LS-DYNA software was used to study the formation of penetrator of single EFP shaped charge warhead and different structural combination of shaped charge warhead, as well as the damage of penetrator to target, after verified the effectiveness of the selected model and material parameters. The results indicate that with the addition of top liner before a single EFP liner, the penetrator with higher head velocity and longer configuration can be formed under the shaped charge. Under the condition that the bottom diameter and height of top liner are 0.2 times the diameter of the charge, when the top cone angle is 30°, the head velocity of the penetrator formed by the combined liner is higher than that formed by other combined liner, and the length of penetrator formed by the combined liner is longer than that formed by other combined liner. However, the diameter of the penetrator formed by the combined liner is the smallest, which is related to the propagation of stress waves in the interior of the liner and whether the microelements around the liner can satisfy the requirement of lengthening the penetrator. The hole aperture and through hole aperture under the penetration of combined liner are positively correlated, the hole aperture and through hole aperture are negatively correlated with the penetration depth under the penetration of combined liner. Under the condition that the bottom diameter and the height of the top liner are 0.2 times the diameter of the charge, the hole aperture of the target under the penetration of the combined liner is not significantly different from that under the penetration of the single EFP liner. The through hole aperture of the target under the penetration of the combined liner is about 0.17~0.2 times of the through hole aperture of the target under the penetration of the single EFP liner. The penetration depth of the target under the penetration of combined liner is about 2.7~3.7 times of the penetration depth of the target under the penetration of single EFP liner. According to the power requirements of warhead, the penetration depth of the target can be increased on the basis of ensuring the hole aperture by adding a proper top liner with a suitable structure.

In view of the outstanding problems existing in the assessment model, method, system and process of assessment of target vulnerability, such as numerous and disorderly assessment models, methods and processes, and poor timeliness and accuracy of assessment system, it is necessary to deeply study the common process of assessment of target vulnerability including assessment model, method and system. This paper mainly uses theoretical analysis, example illustration and other methods to explore it. A common process of assessment of target vulnerability is proposed, it mainly includes characteristic analysis of target, characteristic analysis of damage element, classification of target damage levels, analysis of target critical components, analysis of target damage characteristic and assessment of target vulnerability. Based on this, a system framework for target vulnerability assessment is proposed, which includes the subsystem of target characteristics, the subsystem of warhead power and characteristics of damage element, the subsystem of warhead coincides with target, the subsystem of characteristics of target damage, the subsystem of vulnerability assessment, as well as the subsystems of preprocessing and postprocessing and data management. Integrate artificial intelligence into the assessment system to enhance the intelligence level of the assessment system of target vulnerability. At the same time, each subsystem should be open, allowing content to be added in a standardized format, continuously enhancing its standardization and versatility.

Micro-accelerometers are widely utilized in fields such as inertial navigation due to their compact size and high measurement accuracy. MOEMS (micro-opto-electro-mechanical system) accelerometers, based on optical measurement principles, offer enhanced measurement accuracy and are less susceptible to electromagnetic interference, making them highly promising for future development. However, external environmental changes, particularly fluctuations in temperature, can adversely affect the performance of micro-accelerometers. High-precision micro-optical accelerometers are especially sensitive to temperature variations due to their optical cavity length, which can lead to a decrease in detection accuracy. Therefore, improving temperature stability is crucial. Temperature control is the most effective method to mitigate the thermal effects on micro-optical accelerometer chips. This paper proposes a closed-loop temperature control scheme based on genetic algorithms and fuzzy PID (proportional-integral-derivative) control for a sandwich-structured chip-level packaged MOEMS accelerometer. The work involves designing a temperature control circuit, with a microcontroller serving as the main control unit, determining the controlled object model, then identifying the transfer function as well as tunning and debugging the system's temperature control parameters. The sandwich-type micro-optical accelerometer packaging structure studied in this paper provides favorable conditions for temperature control. The temperature control scheme with PID control parameters optimizes based on fuzzy logic and genetic algorithms exhibits excellent control performance and shorter regulation time. Theoretically, it significantly reduces the temperature control error by several orders of magnitude, effectively minimizing the thermal effects on high-precision micro-optical accelerometer chips. This temperature control scheme also demonstrates strong robustness, making it practically applicable to other micro-sensors with small, semi-enclosed structures.

The dynamic behavior of hemispherical resonator comprises the physical basis of hemispherical resonator gyros (HRG). This paper concerns the common problems that exists in the domestic researches of dynamic modeling of HRG to date, such as the lack of specific sources of reference, plenty of ambiguous deductions (some are even incorrect), hence the derivation process of dynamic modeling of resonator is carefully presented in detail. The paper summarizes the general background knowledge of relevant disciplines, and teases out two main types of modeling thoughts, in the sake of providing a theoretical support for the subsequent researches and engineering applications. Firstly, the elastic shell theory used as a general basis in dynamic modeling of hemispherical resonator is introduced, including the elastic geometric equations that describe the relationship between strain and displacement and the Hooke’s law that relates strain to stress; then the modeling method based on the d’Alembert principle commonly used in early theoretical researches is presented, and the second-order motion equations of resonator is obtained by establishing equilibrium equations and load analysis; finally, the modeling method based on Lagrangian mechanics which is inspired from aboard research is introduced, and the second-order motion equations are derived by calculating the kinetic and strain energy of the overall resonator with substitution of the Lagrangian equations. The latter method is increasingly popular by domestic researchers in recent years.

In this paper, a trajectory optimization method of hypersonic glide missile is put forward by using penalty function method to hand non full course flying height and angle of attack constraints, which is based on Gauss Pseudo-spectral Method and takes into account multi phases, multi complex constraints and penetration mission-oriented requirements and so on. Its simulation results show that all constraint indexes are effectively controlled, and the penalty function method has more advantages in handling mission segmented constraints compared to conventional segmented constraint methods, which verified the effective coverage ability of the method under different ranges, launch heights and target heights.

In order to strengthen the detection capability of small infrared targets under complex background, an improved WSLCM(weighted local contrast measure) detection algorithm is proposed. In the pre-processing stage of WSLCM, adaptive curvature filtering is used to process the image in multi-scale, and the real object is not submerged in the process of background suppression. In the background suppression calculation, the maximum gray value of the background block is selected as the background estimation to reduce the false alarm rate. At the same time, target enhancement factor and background suppression factor are introduced to enhance the robustness of the algorithm, eliminate the influence of background noise, and enhance the detection ability of infrared small targets. The algorithm IP verification is carried out by the embedded ZYNQ platform, and the algorithm can recognize and detect the small target in the specific scene by using the hardware and software cooperation. Experiments show that compared with the traditional WSLCM algorithm, BSF and SCRG indexes are significantly improved, the continuous frame detection rate is 93.2%, and the detection efficiency of embedded platform is 17.6% higher than that of PC, which verifies the effectiveness of the algorithm and embedded system.

With the progressive complication of modern war scenarios, traditional loitering munition which is only suitable for a unitary combat environment is failed to meet the needs of the actual warfare. The trans-medium loitering munition swarm can lead to revolutionary changes of modern military field due to its excellent multi- scenario adaptability. A comprehensive analysis is given from three aspects: the basic design of loitering munition, the unique performance of trans-medium aircraft, and the intelligent management of swarm technology. The core theory and technology of trans-medium loitering munition swarm are studied. Based on the new characteristics of equipment, command, and personnel in modern wars, the future development trend of trans-medium loitering munition swarm is prospected.

To study the influence of the composite microburst wind field on the cruise phase of a light and small fixed-wing unmanned aerial vehicle (UAV), in this paper, a Dryden atmospheric turbulence model and a microburst model are constructed, and after fusing them, a composite microburst wind field model is created. Take a specific electric-powered UAV as the object of study and carry out a six-degree-of-freedom rigid body ballistic model simulation analysis, the simulation results show that the newly established composite wind field model has better randomness and typical wind shear characteristics and it can effectively depict the actual composite microburst wind field distribution and change. Under the influence of this composite wind field, the UAV has experienced a significant loss of height, and when the central induced velocity is between 10~25 m per second, the loss of height reached 168~537 m. Furthermore, the flight parameters of UAV, including flight duration, angle of attack, sideslip angle, and power margin, have changed in different degree.

A sliding mode robust control strategy based on an adaptive first-order sliding mode disturbance estimator and a two-phase combined function reaching law is proposed for the control problem of uncertain quadrotor aircraft system. The quadrotor aircraft system is divided into two fully-actuated subsystems and two under-actuated subsystems, and the sliding surface of each subsystem is constructed by adopting proper sliding surface design method. A continuous adaptive first-order sliding mode disturbance estimator is adopted to online approximate the uncertainties of each subsystem, and a two-phase combined function reaching law that can dynamically adapt to the variation of the sliding surface is used to sequentially design the control amount of the fully-actuated subsystems and the under-actuated subsystems. The stability of the closed-loop control system and the convergence time of the sliding surface of the control system are theoretically analyzed. The simulation test results verify the robust control performance and controller chattering reduction ability of the proposed sliding mode control strategy.

Artificial intelligence technology is widely used in the military field, which significantly improves combat efficiency and promotes the development of military technology. The US military is in a leading position in the research and application of artificial intelligence technology in the military field, which was discussed in detail. The application of artificial intelligence technology in intelligence, surveillance and reconnaissance, logistics support, cyber operations, command and control, semi-autonomous and autonomous vehicles and autonomous weapons and other fields are deeply analyzed, and the future development trend of artificial intelligence technology in the military field is predicted. Finally, it points out the guiding and referential role for the domestic military field to carry out artificial intelligence technology research.

In order to analyze the internal flow characteristics of SRM with tail-pipe nozzle, a differential interior ballistic program is developed to solve the interior ballistic of the motor, and meanwhile the mass inlet condition established by using the custom function, the combustion surface displacement simulated by a dynamic grid technique, and the Euler-Lagrange model combined with the particle random walk model are used to conduct a contrastive study on the three-dimensional two-phase transient internal flow field of SRM with tail-pipe and no tail-pipe. The study compares performance of the SRMs and analyzes influence of the tail-pipe nozzle on gas phase flow characteristics and motion distribution of particles with different diameters. The results show that: the tail-pipe nozzle can cause frictional drag, and its internal equilibrium pressure is higher than that of the motor without tail-pipe nozzle, which leads to acceleration of the charge combusting and decrease of the output thrust; Flow velocity of the gas flowing through the tail-pipe area increases obviously, but the particle action will cause oscillation of the flow velocity and temperature near the axis, and the change of temperature is small, so the thermal protection in the area should be considered. Because of inertia, particles converge first and then diverge in tail-pipe area, with the increase of particle size, the particle convergence area goes further forward, the degree of dispersion is greater, and the effect of turbulence on particle motion is smaller.

In order to solve the problem of aerial alignment of UAVs under situation of satellite navigation, an adaptive feedback alignment algorithm based on improved OBA(optimization-based alignment) alignment algorithm is proposed to unify the process of coarse alignment and fine alignment. After OBA algorithm, the adaptive Kalman filter is used in each step to estimate the sensor error and compensate the attitude of the carrier. The real-time attitude of the carrier is directly output by the system, and the alignment time is shortened. The Sage-husa adaptive estimator is used to correct the observed noise covariance matrix of the system, and then the adaptive factor is reconstructed to correct the covariance matrix of the system state variables. The sensor error is estimated by KF (Kalman filter), and the observed vector is compensated through the feedback channel and that iterate constantly on the attitude angle alignment results. Simulation experiments are designed and simulate the unknown random errors in the velocity and position information given by satellite navigation, it is found that the improved OBA adaptive feedback alignment algorithm effectively improves the alignment accuracy and application scenarios of the original OBA algorithm, and the heading angle error is reduced from 79.45° to -0.032°. The comparison between the proposed algorithm and EKF (extended Kalman filter) shows that the convergence time of pitch angle and heading angle of the proposed algorithm is about 30 s shorter than that of the EKF algorithm. After the convergence of the EKF algorithm, the error of the proposed algorithm is 2.203° smaller than that of the EKF algorithm. The proposed algorithm has more advantages in the initial alignment for large misalignment angle with unknown measurement noise, and can be applied to the initial alignment of large maneuvering aircraft.

Aiming at the problems of uncontrollable drop point and insufficient strike accuracy of the traditional terminal sensitive projectile, this paper proposes a parafoil based terminal sensitive projectile drop point control technology, which adopts parafoil instead of traditional parachute to achieve accurate control of its drop point. Based on the proposed parafoil-missile system, this paper designs an accurate parafoil-missile yaw angle controller based on active disturbance rejection control technology, which can offset the interference caused by the external wind field and compensate for the initial position error of the non-sensitive missile, so as to achieve accurate autonomous control of the system. Based on the above research content, the parafoil- missile system is built in this paper, and the actual airdrop experiment is carried out. In the experiment of airdrop, the error of the final landing point of the parachute-projectile system is less than 30 meters, and the minimum error of the air level is less than 4 meters, which proves the effectiveness of the proposed algorithm and provides a new idea for the design of smart ammunition in China.

Based on test data such as fragment spherical target tests and fragmentation tests, empirical formula of fragment initial velocity and formula of velocity synthesis are used to calculate the lethal probability, and to obtain the variation law of the lethal area with angle, velocity, and explosion height. When the angle of impact is small, the ground isosurface of mnbvcxzlethal probability presents a C-shaped structure. As the angle increases, the opening of the C-shaped structure gradually decreases and eventually closes into a circular shape. The lethal area of fragments is greatly affected by changes in the angle of impact, and is relatively less affected by factors such as falling speed and explosion height. Under the condition of constant explosion height, the lethal area does not change significantly with the increase of falling speed, but there is a peak at the angle of 80° and falling speed of 550 m/s. Under the condition of constant falling speed, the lethal area shows a trend of increasing firstly and then decreasing with the increase of explosion height.

Under the special configuration the airfoil rocket sled, an engineering prediction code based on the numerical flow simulation method as well as the six degrees of freedom function was used to investigate the angle of attack of missile and the relative missile-sled position in the separation process. The influence on aerodynamic moment of the missile from the ground effect as well as the aerodynamic interference between the missile and sled was studied. In the meanwhile, the influence in the center of pressure and angle of attack of missile from the presetting angle of attack, separation speed and track parameters was studied. The conclusions would point out some technical directions to optimize the missile-sled separation plan for the airfoil rocket sled.

Aiming at the problem of multi-missile cooperative attack on enemy air targets, a multi-missile and multi-constraint three-dimensional cooperative guidance method based on sliding mode control theory and artificial potential field method is deduced. Firstly, according to the relative motion of the missile and the target, a three-dimensional non-linear model of the relative motion between the missile and the target was established in the line-of-sight coordinate system. Then, taking the remaining flight time of multiple bombs as the coordination variable, based on the finite time consistency theory, the guidance law of the direction of sight of multiple bombs is designed, which realizes the coordinated attack on the target. On this basis, the normal direction of sight guidance law of multi-missile is designed through the sliding mode control theory, so that the multi-projectile can hit the enemy target at a given line of sight angle, and according to the convergence characteristics of the sliding mode surface, the parameters are adaptively updated to reduce the sliding mode parameter selection complexity. In addition, considering the difficulty in obtaining target maneuver information, an expanded state observer is designed to efficiently predict target acceleration information. Finally, combined with the idea of artificial potential field method, a multi-missile obstacle avoidance control command is designed to effectively avoid constraints such as avoidance zones during multi-missile flight. The simulation results verify the effectiveness of the proposed guidance method.

For missile's precision guidance task, an optimal leading angle sliding mode control algorithm based on GA-BP (genetic algorithm-back propagation) is proposed, in which the sliding mode control is improved segmentally. Aiming at the problem of the fixed leading angle sliding mode control depending on a leading angle value, but it is difficult to be predefined, a GA-BP neural network is developed and used to estimate the optimal leading angle for a specific task model. Subsequently, based on the estimated value of remaining time, a piecewise sliding mode reaching law is designed, which lead to a segment-improved sliding mode control algorithm that further enhances robustness during the missile guidance process. And then the complete optimal leading angle segment-improved sliding mode algorithm based on GA-BP is formed. After the algorithm is simulated and analyzed, Simulation results indicate that, compared with the fixed leading angle sliding mode control algorithms, the proposed algorithm can reduce task time approximately 5% in average, and the overload around 12%. As it can reduce the task time by up to 30% in the maximum, so it has a higher superiority.

In order to enhance the penetration capability of the shaped charge warhead, a shaped charge with waveshaper-liner linked was proposed. To investigate the influence of the structural parameters of the propellant cover on the velocity of the jet head and the penetration ability of the jet, LS-DYNA finite element software was used to numerically simulate the structure of the shaped charge with waveshaper-liner linked. The research results indicate that the maximum penetration depth of the jet increases first and then decreases with the increase of the width of the cylindrical part of the propellant cover, and increases with the increase of the height of the cylindrical part of the propellant cover. When the explosive height is 2.5 times the diameter of the charge, the optimal penetration effect can be achieved by having a cylindrical height of 14 mm and a cylindrical width of 18 mm for the shaped charge cover. The maximum penetration depth for the 45 # steel target is 478.1 mm, and the contact speed can reach 13 650 m/s. The research results have certain guiding significance for the design of concentrated energy warheads.

In order to meet the requirements for reducing flight speed in the subsequent process of some long-rang rocker subcarrier ammunition,a study is conducted on the scheme of using body to achieve deceleration.A typical structure for implementing body deceleration scheme is selected in the articl, and the main aerodynamic parameters were calculated,and the aerodynamic characteristics were analyzed. Ballistic model is established using quaternion method,and through ballistic numerical simulation,ballistic characteristics is analyzed.Finally,the mechanism fo the body deceleration scheme is studied,and a method for optimizing design was proposed.For typical main body deceleration schemes, the deceleration effect is best achieved by designing the center of mass position at the pressure center position at a speed of 200 m/s and an angle of attack of 90° or 270°.

With the enhancement of overall warhead damage as the research objective, this study addresses the issue of the poor formation effect of natural fragments generated by the detonation of solid rocket engines. Research is conducted on the grooving of the combustion chamber casing. Following the research sequence of transverse grooved cylinder-longitudinal grooved cylinder-transverse and longitudinal grooved cylinder-transverse and longitudinal grooved combustion chamber casing, the impact of different transverse, longitudinal, and combined transverse and longitudinal groove parameters on fragment formation is analyzed. Parameters suitable for the casing of large-diameter, thin-walled engine combustion chambers are obtained, and the damage power of the obtained groove parameters is analyzed. The results indicate that, under the premise of a large-diameter, thin-walled cylinder, a groove spacing greater than three times the wall thickness can form regular fragments. Although an increase in groove spacing reduces the number of fragments, the mass of individual fragments increases, resulting in a higher damage range. The parameters of groove depth and width are relatively close to those of warhead groove parameters, and the depth of the transverse groove significantly affects the generation of pre-controlled fragments. However, excessively deep grooves will exceed the safety range of the engine casing, hence the selectable range for transverse groove depth is relatively small. The conclusions of this study can provide a reference basis for the integrated design of projectile and rocket propulsion damage.

The combination of semi-active laser detection guidance and infrared imaging guidance can obtain active and passive detection modes, improving the seeker’s all-weather detection ability, anti-interference ability and target capture tracking ability. The performance of the optical system in the laser infrared composite guidance seekers directly determines the detection range, target recognition and hit accuracy of the guided weapon system. The composite seeker adopts a separate aperture optical system, and each channel adopts a separate optical structure and detector, which is easier to achieve, but it will bring problems such as spatial registration, and the system volume and mass are large. In this paper, a common aperture optical structure is adopted, and the transmittance of laser (1.064 μm) and infrared (8~12 μm) spectral bands is considered, and the composite optical design is achieved by using a focal length matching method to share a fairing and a high transmittance lens. The laser signal is focused through the fairing and the first lens, which is then reflected to the side of the lens barrel by a planar mirror located in the center of the aperture, which is received by a four-quadrant detector. The infrared light signal passes through the periphery of the aperture and is imaged onto an uncooled focal plane detector by three lenses containing diffractive lenses. The whole optical system through -45~60 ℃ no heating design, the overall structure of the optical system is simple and compact, small size, the total length is less than 86 mm, the caliber is less than 62 mm. The optical system design can be applied to laser infrared composite guided rockets, missiles and other weapon platforms, providing technical reserves for high-tech warfare with high efficiency and cost.

Accurately and quickly detecting military targets in complex scenarios has important military value in perceiving battlefield situations, conducting reconnaissance and early warning analysis, and providing precise missile guidance. A multi-scale object detection algorithm AEM-YOLOV5 (AFPN-EMA-MPDIoU-YOLOV5) based on improvements to YOLOV5s is proposed to address the issues of poor feature learning ability, low detection accuracy, and high computational complexity in existing algorithms. Firstly, the AFPN asymptotic feature pyramid network is introduced into the neck network to gradually fuse the detailed information at the bottom of the image and the high-level semantic features at the top, enhancing the network feature fusion effect. Secondly, an EMA attention mechanism module is added before each detection branch to aggregate pixel level features across spaces, improving the level of attention to multi-scale targets in complex scenes. Finally, MPDIoU is used to replace the original C_IoU bounding box loss function in YOLOV5, solving the problem of C_IoU degradation when the predicted box aspect ratio is the same but the absolute value is different, making the regression results more accurate. The experimental results show that the improved algorithm performs well on the RSOD dataset, P_mAP50 reaches 94.5%, FPS reaches 42 frame/s, and model size is 14.8 MB. Compared with existing algorithms, the improved algorithm significantly improves its performance, meets the real-time requirements of military target detection, and the model is lightweight.

In order to maximize the available maneuvering overload when the missile enters the terminal phase, for a certain type of helicopter-borne missile, this paper builts a model to optimize the ignition time of its sustainer, considering the stability of the missile and the constraints of flight time. The results show that Hooke-Jeeves and ASA have reached a similar conclusion: the ignition time of sustainer is optimized to 30.1 s, ensuring the stability of the missile and the constraints of flight time, which increases the speed by 4.3% when the missile enters the terminal phase, thereby increasing the maneuvering overload in the terminal phase.

In order to provide reference for the analysis on exterior ballistic environment of fuze, FLUENT software is applied to numerically simulate the aerodynamic characteristics of a large caliber dynamic imbalance spin-stabilized projectile with base cavity, and corresponding aerodynamic characteristics of the whole trajectory are obtained. The function relationship of aerodynamic characteristics, dynamic imbalance angle with Mach number of the projectile is fitted 1stOpt software. The influence exerted by dynamic imbalance angle on drag coefficient is small and within 2% lift coefficient, overturning moment coefficient and polar damping moment coefficient are positively linearly correlated with dynamic imbalance angle of the projectile while Magnus force coefficient and Magnus moment coefficient are negatively linearly correlated with dynamic imbalance angle of the projectile. When dynamic imbalance angle is large (such as 1°), polar damping moment coefficient will increase 2~4 times compared with that dynamic imbalance angle is zero.