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It is very hard to position helicopters in complex environments, and this severely limits their ability to navigate on their own. This paper proposes a navigation algorithm that uses a combination of different sensors and deep learning. It uses a special type of deep learning called ResNet50 and a special type of machine learning called LSTM. This algorithm extracts features of the environment and uses a Kalman filter to estimate the state of the system. The system is made more robust by merging information from multiple levels. The algorithm’s ability to maintain stable navigation in the face of faulty sensors is noteworthy, as is its use of an adaptive inference strategy that dynamically adjusts computational load. This strategy strikes a balance between performance and resource consumption. Experiments show that the plan works well in places where GPS is not available. This makes it much better for the helicopter to fly by itself, and it can be used in places like the army, for looking at places from the sky, and for helping people in danger.
Yang, Ming
Craters are the primary landmarks used for visual navigation in missions exploring small celestial bodies. However, obtaining high-quality, annotated crater data is often challenging due to limited imaging conditions and strict mission constraints. Conventional semantic segmentation models struggle with limited data and are challenging to train effectively. To overcome this limitation, this study introduces a few-shot segmentation approach for crater detection on small celestial bodies. Our method includes a prototype representation module that constructs class-level prototypes to quickly associate crater regions with their semantic features. This paper also designs an iterative learning module that gradually improves the segmentation output, helping the model better capture detailed edges and structures. Tests on a simulated few-shot dataset demonstrate that our method provides reliable and accurate crater segmentation, achieving a mean intersection-over-union (mIoU) of 88.7, outperforming traditional fully supervised methods.
Li, ShuaiZhu, Shengying
This paper investigates the tracking of highly maneuverable targets during flight and the corresponding satellite scheduling problem in a space-based observation system. Based on dual-satellite measurements, a nonlinear observation equation was formulated. The J2 perturbation model and the current statistical model were utilized within an Interacting Multiple Model filtering framework to achieve adaptive estimation of the target states of the boost-glide vehicles. Building upon this framework, a greedy satellite scheduling algorithm based on IMM model probabilities is proposed. This method dynamically selects the optimal measurement set within a given prediction window to maximize observation performance. The proposed strategy is compared against rolling-horizon scheduling and fast-slow timescale scheduling approaches. Simulation results demonstrate that the proposed method effectively adjusts model weights in response to target maneuvers, enhancing adaptability during highly maneuverable phases. Meanwhile, it reduces the number of satellite switches while maintaining estimation accuracy, significantly improving scheduling efficiency and tracking continuity.
Deng, SiruiLiu, ChengzheWang, Yandong
This paper systematically optimizes and validates the handling stability of a vehicle using ADAMS/Car software based on vehicle data provided by a car manufacturer. A comprehensive vehicle dynamics model was established, including a body model, an anti-roll bar model, a powertrain model, a steering subsystem model, and a full vehicle model, with a focus on optimizing suspension parameters such as toe angle and camber angle. Validation was carried out using simulation test methods such as dual-wheel synchronous excitation, steering returnability, and angle step input. The results show significant improvements in the vehicle’s yaw rate, steering force, and torque after optimization, with particular excellence in steering return time and transient response. Additionally, steady-state cornering simulation results indicate that the optimized vehicle has improved body roll stiffness and lateral compliance, with increased understeer, further enhancing stability and response speed during steering. The findings of this study improve the handling stability and safety of vehicles and provide valuable references for future automotive design.
Li, DiannuoZhu, JialeWang, DongmeiWei, YiHuang, YuanyuanBan, Lu
This study develops an end-to-end load analysis scheme for flap and slat actuators, which comprise the aircraft’s high-lift system, and the analysis results are directly integrated into hardware optimization. Because they shoulder heavy responsibilities during the takeoff and landing phases, whether they can remain rock-solid under complex aerodynamic conditions or even remain unmoved in emergencies is directly related to their overall safety performance. This work process is closely linked and includes three major links. First of all, according to the CCAR-25.301 standard, the load envelope under normal working conditions is sorted out, and the limit cases of abnormal faults are exhausted. Subsequently, ANSYS Workbench pulled silk and peeled off the cocoons to capture the peak stress at the engagement between the output shaft and the gear. In the end, the closed-loop verification of the customized test bench made the theoretical calculations and the hardware-measured data exactly the same. The entire package provides designers with hardcore data support, and always uses airworthiness, not convenience, as the criterion when improving actuator performance.
Xu, Yuanze
Pollution in the oxygen system of civil aircraft may lead to fire accidents, and maintaining the cleanliness of oxygen equipment is the most effective measure to reduce the risk of fire. This paper introduces the cleanliness requirements, cleaning methods, and procedures of oxygen equipment, and combines the cleanliness level requirements of oxygen equipment for a certain type of civil aircraft. By detecting the total weight of Non-Volatile Residue and the size and quantity of particles on the surface of the parts, it verifies whether the specific cleaning process can meet the cleanliness level required by the design. In addition, the possible sources of pollutants are analyzed based on the first unqualified verification results, and targeted improvement directions for the process are provided. After re-performing the cleanliness verification test, the results passed successfully, indicating that the process improvement is effective and has passed the airworthiness certification of the reviewer.
Huang, Jingqi
In this paper, we focus on satellite production lines and design and implement a digital twin simulation and verification system for them. This is to improve manual documentation efficiency and provide sufficient process controllability in the small satellites’ batch production and assembly testing. We built a layered architecture. This allows the system to dynamically interact with AIT data management systems, structured process systems, and equipment data by fusing multi-source data. We also develop functional modules that combine lightweight 3D model visualization, dynamic simulation engines, and hybrid scheduling optimization algorithms. These modules can perform twin simulation, execute processes, intelligently schedule production, manage work reporting, conduct intelligent analysis, trigger anomaly alarms, and perform system management. We also dynamically simulate complex workflows like satellite transfer and automated assembly. These workflows are then verified using 3D virtual scene modeling and physical engines. We use time-series analysis to improve scheduling accuracy and multidimensional dynamic monitoring and hierarchical response to enhance production stability. In practice, the system can provide visualized control over the full process of satellite production. This greatly improves assembly efficiency and process controllability. It can also be an extensible digital way for aerospace manufacturing. The use of hierarchical architecture design and multimodal data fusion can be further applied in the complex equipment intelligent manufacturing.
Zhao, Fenghua
To analyze flight test failures, ensure flight safety, and provide data support for the aerodynamic design of helicopters, it is necessary to conduct aerodynamic characteristic analysis of helicopter rotors based on flight test data. This article establishes a helicopter rotor aerodynamic model and an aerodynamic parameter identification method in level flight. In this article, we take the flight test data of a helicopter’s level flight performance as an example, and use the genetic algorithm and Particle Swarm Optimization for parameter identification calculation. We obtain aerodynamic parameters such as rotor angle of attack and rotor lift-to-drag ratio in the helicopter’s level flight state, and so on, and analyze the aerodynamic characteristics of the helicopter’s rotor. The results show that the method established in this paper can accurately and effectively obtain the aerodynamic parameters of the helicopter rotor through flight tests. It can also evaluate the aerodynamic characteristics of the helicopter rotor and meet the requirements of the American standard ADS40 for obtaining the aerodynamic characteristics of the helicopter through flight tests. Thus, it has great engineering application value.
Zhao, Jingchao
With CFD technology, a numerical simulation method based on the Navier-Stokes (NS) equations with slip boundary conditions was established. For the flow conditions at altitudes of 60 km and 70 km with a Mach number of 20, the calculation convergence problem of slip flow was analyzed through a flat plate. The research shows that as the altitude increases, the degree of rarefaction increases, and the frictional drag decreases. Without slip, the viscous drag decreases from 17.8 N at an altitude of 60 km to 9.97 N at 70 km. With a slip, it decreases from 17.5 N to 9.63 N. After adding the slip condition, the calculation convergence is slower compared with that of the non-slip attached flow. The difference between the calculation results with and without slip increases as the altitude increases. During the iteration process, the difference between the cases with and without slip gradually decreases. The difference in viscous force between the cases with and without slip is 1.76% at 60 km and reaches 3.47% at 70 km.
Hu, JunlinWang, YapingGao, YunguangWan, LvPan, Sha
Analysis of cabin depressurization is key to ensuring civil aircraft airworthiness safety. In this study, we use a comprehensive approach to analyze depressurization scenes under regulations such as CCAR 25.841. For cases with and without cabin altitude warnings, we calculated critical leakage areas using an orifice flow model and iterative numerical methods. This combines inputs like emergency descent envelopes, air supply rates, and cabin parameters. In our analysis, we evaluate system failure impact and structural breaches on cabin pressure dynamics. For cases where the critical leakage area failed to meet the limits, we use an equivalent safety analysis based on the Depressurization Exposure Index (DEI). This combines pressure and exposure duration to measure physiological risks. We validated this approach through Simulink simulations and case studies, and found that it supports airworthiness verification, emergency descent optimization, and structural design improvements. This method provides a robust framework for enhancing civil aircraft depressurization safety.
Zheng, Bian
Efficient optimization of aerodynamic shapes is a critical challenge in aircraft design. Traditional CFD-based optimization workflows suffer from high computational costs and low efficiency, which severely restricts their practical engineering application. In this paper, a novel aerodynamic optimization method based on a hierarchical neural network with adaptive activation functions is proposed. The network adopts learnable B-spline activation functions and is hierarchically constructed in accordance with the sharing status of B-spline control points. After being trained to achieve fast and accurate prediction of aerodynamic performance, the network can effectively replace the traditional CFD module in the optimization loop. The primary advantage of the proposed method is that it significantly reduces the computational cost during the optimization process while ensuring that the prediction accuracy is not compromised. This work thereby presents a novel strategy and technical framework for streamlining the design process of hypersonic vehicles.
Liu, DiWang, YongfengWen, HongWei, YuanhangMa, HengweiZhao, Runhui
This paper investigates the high-precision landing control problem of carrier-based aircraft. An Active Disturbance Rejection Control (ADRC) technique is employed to design longitudinal and lateral-directional landing control laws. The landing process is simulated by incorporating an airwake model, and the results are compared with those of a PID control law. The analysis demonstrates that the proposed ADRC controller reduces lateral deviation errors and significantly improves landing accuracy and success rate.
Yu, JiayangYin, Yong
When an amphibious aircraft is taxiing on a wavy water surface, the force of the water directly concentrates on the floats, directly affecting the stability of the aircraft’s taxiing process. The vortices generated by the wave undulations exert significant hydrodynamic forces on the floats, thus impacting the stability and maneuverability of the float’s taxiing process. This study uses CFD numerical simulation to simulate the float’s taxiing process on a wavy water surface. By comparing the pressure distribution and vortex contours of the float under different wave height parameters, the effect of wave height on the hydrodynamic mechanism can be elucidated. The results show that the effect of wave height on aircraft stability is closely related to the position of the impact point when the wave crest hits. At a wave height of 0.5 meters, if the impact point is close to the center of gravity, it can lead to instability of the aircraft. These conclusions provide an important theoretical basis for the design and optimization of amphibious aircraft floats.
Zhang, FeifanLi, ZhandongZhao, JinfangKong, FanweiQu, Ligang
Topology optimization provides innovative solutions for lightweight structural design by rationally arranging material distribution. It enhances structural performance while reducing material consumption and structural weight, thereby significantly lowering production and operational costs and generating enormous economic benefits. In the development of topology optimization, the density-based method has gained widespread adoption due to its easy-to-understand principles. However, this method still faces the following challenges when applied to engineering applications. First, the geometric models generated by topology optimization lack explicit parameter descriptions, leading to data interaction barriers with Computer Aided Design (CAD) systems. Second, due to element discretization and density penalty mechanisms, structural boundaries exhibit rough and blurred characteristics. These problems severely constrain the iterative efficiency of structural design and manufacturing feasibility. To address these issues, this paper proposes a strategy for geometric reconstruction and shape optimization of topology optimization results. The reconstruction process begins with extracting isolines from the density field as a set of contour points. These points are subsequently interpolated with B-spline curves to explicitly represent the geometric boundaries. Shape optimization is then carried out by adjusting the positions of the B-spline control points. Compared to post-processing methods based on graphics techniques for topology optimization, which ignore the volume constraint and performance loss, the structures reconstructed in this paper exhibits the following advantages: structural boundaries are smoothed and characterized with explicit parameters, reducing performance loss caused by geometric reconstruction while satisfying volume constraints. This paper successfully establishes compatibility between topology optimization and CAD systems, facilitating the transition from conceptual design to manufacturing.
Tang, YutingLi, YuLuo, JiaxiangChen, JunweiZhou, WeienYao, Wen
The numerical simulation of the transformation process of multiple droplets into liquid films is a complex problem involving multiphase flow, interface dynamics, and heat and mass transfer. It usually requires the combination of fluid mechanics, interface science, and numerical calculation methods. Based on the smooth particle fluid dynamics method, this paper establishes a multiphase fluid-solid coupling interaction model among droplets, surrounding air and solid walls, and studies the dynamic change process of multiple raindrops dispersed in different grooves. The results show that when the contact Angle is small, the boundaries of multiple raindrops do not come into contact. The multiple raindrops evolve in their respective grooves and eventually form multiple raindrops that approach the steady-state contact Angle. The second situation is that the boundaries of multiple raindrops do not come into contact, the raindrops start to fuse, and multiple raindrops form a larger one. At this point, the contact point of the gas-solid-liquid phase disappears, that is, the "regulating force" of the contact Angle is 0. This paper provides important numerical simulation references for flight safety, aerodynamic performance and anti-icing/de-icing technologies during the flight of aviation aircraft.
Huo, YeChen, YonghengSun, Cunxiang
The climb gradient along the takeoff trajectory at each point during takeoff reflects the aircraft’s ability to clear obstacles and reach a safe altitude, ensuring the safety of civil flights. Airworthiness regulations specify certain requirements for the single-engine-out climb gradient. Given that the data used in conventional calculation methods are significantly influenced by the flight status during the process, this paper explores two new climb performance calculation methods based on the existing ones. A set of data was calculated, and the resulting errors were all no more than 10%, indicating that both new calculation methods are effective and reliable. Therefore, they provide a certain reference value for the climb gradient calculation of transport category aircraft.
Jiang, TianjunLiu, Tao
The structural stiffness of a manned lunar vehicle is a core indicator ensuring its stable operation in the complex lunar environment. The vehicle’s body structure must meet multiple requirements, including high stiffness, lightweight design, and adaptability to lunar surface conditions. Since lunar gravity is only 1/6 of Earth’s and the terrain is rugged and dusty, the body structure must employ a high-stiffness design to withstand driving impacts and resist deformation, thereby preventing mechanical failures or safety hazards for crew members caused by excessive structural distortion. However, excessive structural stiffness would result in an overweight vehicle body, conflicting with the spacecraft’s lightweight requirements. Thus, the structural stiffness index should be optimized to a lower value while ensuring safe operation during lunar surface driving without compromising performance. This paper calculates and determines the structural bending and torsional stiffness indicators for the manned lunar vehicle’s body through simplified model calculation and the FEA method.
Shen, ZhenghuiWu, YingjiaYang, JianfengWang, WeijunZhang, ChongfengHan, Liangliang
Test results of the composite helicopter horizontal central-wing under symmetric and unsymmetric loads showed that the strain value of the lower skin would turn from negative to positive, showing a nonlinear behavior. FEM results of the linear and nonlinear analytical approach showed a great difference. The strain value of the lower skin remains negative and decreases linearly when using a linear FEM analysis. The strain value of the lower skin would turn from negative to positive when a nonlinear FEM analysis is applied, and this result agrees well with the test results. Besides, the results of the FEM buckling analysis showed that the buckling load of the lower skin is considerably higher than the value at which the skin would show a nonlinear behavior. Therefore, the specific behavior is a result of the nonlinear property of the structure, not buckling.
Wang, ZheZhang, TiesongLi, MengjiaChen, PuhuiHuang, ZhiwenWang, Binwen
Product options are an important means for civil aircraft manufacturers to meet market demand, increase revenue, and enhance competitiveness. How to achieve a customized configuration of civil aircraft options is the focus of attention for aircraft manufacturers. In order to reduce manufacturing costs and cover more target markets, it is necessary to pay attention to the customized detail design of aircraft products in the early stages of design. At present, academic research on product selection is relatively limited and lacks quantitative evaluation methods. This article selects four elements to form an evaluation indicator system, namely comfort, competitiveness, cost investment, and maintainability; establishes a civil aircraft option evaluation model based on grey correlation analysis, quantifies the degree of correlation between product options and customer needs, and uses the analytic hierarchy process to reflect the weight differences of evaluation indicators. Taking the option list of a wide-body aircraft as an example, the model was used to evaluate and rank the options, verifying the rationality of the model and providing a reference for aircraft manufacturers to make provisions in advance.
Lu, Meihua
The verification of Precipitation static (P-static) protection for the radio navigation system of civil aircraft is a critical test item for airworthiness certification. However, determining the presence of P-Static on the aircraft fuselage and assessing whether its discharge interferes with the radio navigation system remains challenging, with testing methods still under exploration. By analyzing airworthiness certification test provisions, the necessity of conducting flight tests for P-static protection verification of the radio navigation system was clarified. Based on existing conditions for civil aircraft flight tests, a comprehensive flight test method was proposed to verify the P-satic protection capability of the radio navigation system. This method includes determining external meteorological conditions, measuring electrostatic parameters, and designing aircraft maneuvers and states. The test plan was validated on a test aircraft. Discharge current data measured on a discharger indicates that during the flight of a civil aircraft through cirrus clouds, negative charge accumulated on the aircraft's surface, leading to electrostatic discharge. The maximum peak discharge current recorded was 330 μA. P-satic radiation field data were obtained near the Automatic Direction Finder (ADF) antenna; the radiation energy is primarily concentrated within the 200 MHz range, with some energy distribution still observed between 200 MHz and 500 MHz. Within the 200 MHz range, the signal amplitude exceeds the background noise, and stable peaks appear at multiple frequency points, with the maximum amplitude reaching up to 50 dBm.confirming the presence of a P-Static environment. This achieved the objective of evaluating the functional performance of the radio navigation system in an electrostatic environment, providing technical support for P-Static protection verification flight tests and offering a reference for the practical application of electrostatic protection design.
Han, ChunyongWang, Fusheng
This paper focuses on autonomous drone landing scenarios. Addressing the core requirements of accurate landing site assessment and intuitive visual presentation, it conducts in-depth research on the application of 3D LiDAR (TOF technology) point cloud data. LiDAR captures point cloud data containing 3D coordinates and reflection intensity values. While sparse, non-uniform, and disordered, its high measurement accuracy and strong anti-interference capabilities make it a key sensor for landing terrain perception. Based on a review of recent research results from related teams, this study designed and implemented a comprehensive technical solution: First, raw point cloud data is acquired via the UDP protocol combined with an SDK interface. Preprocessing is then performed using voxel grid filtering (downsampling) and radius filtering (denoising). The assessment area is then divided into a row-by-column grid. A sliding window method is used to calculate the elevation difference, empty grid ratio, flatness, and slope of each grid. Based on these attributes, the grids are classified into six categories: Risk, Warning, Blank, Unknown, No Landing, and Landing. Finally, a grid attribute coloring method and OpenGL 3D rendering are used to generate the visual scene. Through the development of verification programs and moving obstacle experiments, it has been proven that the solution can efficiently process point cloud data and accurately identify safe landing areas, providing key technical support for the engineering realization of the autonomous landing function of drones, and also laying the foundation for the intelligent development of drone landing decisions in complex environments.
Guo, HangyuShi, Zhe
This paper constructs a reinforcement learning framework based on the PPO algorithm for drone air combat to solve 1v1 pursuit-evasion in 2D beyond-visual-range air combat. Firstly, the mission scenario is modeled, defining key roles of ATA and AA. Then, state transition models of pursuer and evader are built based on flight kinematics. To handle reward sparsity in policy network training, a dense reward function combining distance and angle rewards is designed to guide the agent in learning tail-chasing and interception strategies. Using the Actor-Critic architecture, deep neural networks implement the decision-making and evaluation modules. The PPO algorithm trains the pursuing drone in a simulation. Results show that after ~5 million steps, the agent learns a stable strategy, completing tasks promptly and generalizing well in unseen scenarios. This research offers ideas for drone combat and guidance, and supports autonomous decision-making in complex air battles.
Yu, KangjieGong, ZhengHu, RunchangLiu, Huixiang
This study focuses on the ground testing of an optimized engine-driven pump system for civil aircraft. It proposes the test methods for the pressure pulsation at the pump outlet, the stress and vibration of the pipeline, and the cabin noise level on board. These tests are designed to determine whether the function and performance of the optimized engine-driven pump meet the intended improvement objectives. This paper elaborates on the test objectives of the pressure pulsation test, pipeline stress test, pipeline vibration test, and noise test on ground-based testing of civil aircraft. It proposes corresponding testing methodologies, summarizes the technical specification requirements for selecting different types of test sensors, outlines the principles for selecting test points during the testing process, and presents methods for processing the collected test data. By conducting tests on a specific model of civil aircraft and coupling with comparative analysis of test data, it was found that the pressure pulsation level, pipeline vibration level, and cabin noise level on board the optimized engine-driven pump have been significantly improved compared with the original design. At the same time, it is concluded that the stress level of the optimized engine-driven pump outlet pipeline remained within the allowable fatigue limits of the material.
Li, YingQi, Xiaoyan
Requirements of Interface for Aircraft/Store Electrical Interconnection System (GJB 1188A-99) is the current standard followed by all types of carrier aircraft and stores. This paper designed a 1553B bus remote terminal mode code configuration method that met the requirements of GJB1188A standard, completing the interrupt initialization and data initialization of compulsory mode codes. These comprehensive test results confirm that the proposed mode code configuration method is both reliable and effective, and provides strong portability, which can be used as a reference for the GJB1188A interface software design of other components
Han, BinZhang, KunLiu, XuhanYe, JinhanLi, Zhengmao