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It is with great pleasure and a sense of profound accomplishment that we present the conference proceedings of the 2024 4^th International Conference on Mechatronics Technology and Aerospace Engineering (ICMTAE 2024), which gathered an impressive array of experts, scholars, professors, and engineers from prestigious universities, research institutions, and enterprises worldwide.

The theme of ICMTAE 2024 revolved around the latest research areas, including “Mechatronics,” “Electrical and Electronic Technology,” “Aerospace Engineering,” and “Aeronautical Engineering.” The conference served as an international platform for sharing professional experiences, expanding professional networks, exchanging new ideas face-to-face, and presenting research findings. It aimed to explore the key challenges and research directions facing the development of these fields, promote the development and application of related theories and technologies in universities and enterprises, and facilitate the establishment of research connections among participants, fostering potential global partnerships for future endeavors.

The conference commenced with a series of keynote speeches delivered by renowned experts, including Professor Ian McAndrew from Capitol Technology University, US, Professors Junhui Hu and Yan Wang from Nanjing University of Aeronautics and Astronautics, and Professor Jun Xu from Wuhan University of Technology, China. They delved into the intricacies of mechatronics and aerospace technologies, presenting cutting-edge research and addressing the key challenges faced by the industry. The presentations provided invaluable academic resources and insights, stimulating thought-provoking discussions among the attendees.

List of Committee Member is available in this pdf.

All papers published in this volume have been reviewed through processes administered by the Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

? Type of peer review: Single Anonymous

? Conference submission management system: Morressier

? Number of submissions received: 129

? Number of submissions sent for review: 108

? Number of submissions accepted: 75

? Acceptance Rate (Submissions Accepted / Submissions Received × 100): 58.1

? Average number of reviews per paper: 3

? Total number of reviewers involved: 15

? Contact person for queries:

Name: Xuexia

Email: xx.ye@keoaeic.org

Affiliation: AEIC Academic Exchange Information Centre

The main process of the continued airworthiness system is put forward via collecting the events that may affect the safe operation of aircraft, carrying out engineering investigation and risk assessment, and developing corresponding corrective and improvement actions according to the causes and risks. It aims to continuously improve the safety and reliability of aircraft. According to the proposed process, the continued airworthiness event that the flammable liquid leakage drainage passage test of the aircraft pylon fails is analyzed and disposed of, which ensures the safe operation of the fleet.

Thermal/acoustic insulation blankets are the main material for noise reduction of aircraft panel structures. Due to the lack of design experience of domestic civil aircraft manufacturers, it is difficult to carry out the weight reduction design of the thermal/acoustic insulation blankets based on meeting the cabin noise requirements. Therefore, the sound insulation performances of the metal fuselage panel with different weight reduction configurations of the thermal/acoustic insulation blankets are tested by using the sound intensity method under the condition of an anechoic-reverberation chamber. Based on the analysis of the experimental results, the influence laws of different weight reduction configurations of the thermal/acoustic insulation blankets on the sound insulation performance of the composite panel are summarized, which have important guiding significance for the weight reduction design of the thermal insulation and sound insulation layers for civil aircraft manufacturers.

In response to the influence of different gas models on the flow field structure and thermal environment of a single nozzle rocket first-stage in retro-propulsion, a two-dimensional axisymmetric N-S equation containing chemical reactions was numerically solved. The reverse jet flow field of the rocket configuration was numerically simulated using a frozen perfect gas model and a reacting gas model, and the changes in surface heat flux along the trajectory point of the rocket were analyzed. Research has found that chemical reaction gas models can more accurately describe energy exchange and component changes in flow fields. For the thermal environment of the rocket body, especially at the bottom and top of the rocket body, there is a significant difference between the peak heat flux calculated by the chemical reaction flow and the perfect gas model. Therefore, to accurately depict the supersonic retro-propulsion flow field and aerodynamic thermal properties of the first-stage rocket’s deceleration, advanced measurement and analysis methods are essential, ensuring a precise understanding of flow dynamics and thermal behaviors.

The terminal static seal of metal gasket is extensively employed in cryogenic liquid launch vehicles, with its sealing efficacy being of paramount importance in ensuring flight reliability. Under the action of the preloading torque, the stress distribution of the gasket’s contact surfaces plays a critical role in determining the occurrence of sealing failures. This study focuses on the aluminum gasket utilized in the high-pressure pipeline of a servo mechanism. Firstly, the tightening torque is calculated, followed by the establishment of a simulation model using Ansys to assess the sealing performance of metal gaskets when subjected to high-pressure kerosene at both normal and low temperatures. Subsequently, a test environment is constructed to validate the sealing reliability of metal gaskets. The test results indicate that the metal gasket can be effectively sealed in the low-temperature environment under the tightening torque of 120 N.m, which provides valuable insights for the design of seals in other high-pressure pipelines.

Fibre reinforced polymers (FRP) are widely used in aerospace and mechanical engineering due to their high specific strength and specific stiffness, whereas the connection between composites and metal limits the application of composites. The traditional preloaded tooth connection of composites uses the extrusion method to apply preload. Still, this method has the problem of over-extrusion in the preload application process, resulting in a small preload that can be applied. Shape memory alloy (SMA) is a special metal with a shape memory effect. It is widely used in aircraft hydraulic pipeline fastening and can provide greater fastening force. In this paper, a composite tube connection method based on shape memory alloy to apply preload is proposed. The method comprises three parts: steel inner sleeve, composite tube, and SMA outer sleeve. A larger preload is applied to the joint through the shape memory effect of unidirectional shape memory alloy to enhance the friction at the interface of the composite tube and achieve a higher load-carrying capacity. In this paper, an experimental study on the composite joint method based on shape memory alloy applying preload is carried out to verify the technology’s feasibility and analyze SMA’s fastening force.

The variable stator vane system is a crucial component in preventing engine surge. In this study, a load is applied to the variable stator vanes to conduct a fatigue test, and relevant parameters are collected. The test results show that the force within this system is highly non-linear and complex. The amplitude of force is acceptable.

Sea launch is a new method that eliminates the risk of falling debris threatening ground personnel and property compared to traditional land-based launches. However, during rocket launches and recoveries, sea launch and recovery platforms endure high temperatures, pressures, intense erosion, and high heat flux. The use of protective materials is crucial for stable operation and efficient service. This paper presents two cases of nozzle flame ablation experiments and five cases of oxy-acetylene flame ablation experiments to validate the protective effect of the materials and mitigate risks associated with sea launches. Thermocouples and infrared thermography revealed that the temperature behind the protective material’s backing did not exceed 400 K, and the backing structure remained intact post-experiment, with only surface carbonization observed, indicating effective erosion and ablation resistance.

The nozzle flame jet from the rocket engine during sea-landing recovery can have a significant impact on the recovery platform. Understanding the features of the nozzle flame jet flow field is crucial for the design of the recovery platform. The three-dimensional N-S equations and k-ε turbulence model are adopted. A simplified geometric model of the recovery platform is obtained based on a typical condition where the rocket is 4 meters away from the platform with a protective wall on the right side. Based on these models, a numerical simulation model for the features of the nozzle flame jet during sea-landing recovery is established. Using this simulation model, the features of the rocket nozzle flame jet flow field were numerically calculated.

Aiming at the current engineering and technical problems such as the complex mathematical form of the isothermal combustion mathematical model in the turbine and the use of more complex entropy for calculation in the model, the isothermal combustion mathematical model in the turbine can be derived from the fundamental thermodynamic process principle of the isothermal process. In this paper, the newly developed mathematical model of isothermal combustion in a turbine is analyzed and compared with the mathematical model from literature, and the feasibility and good applicability of the new model are proved through programming calculation. It is proposed that the newly established mathematical model of isothermal combustion in a turbine can significantly improve the programming efficiency and calculation efficiency. In addition, the new model is applied to the overall thermal performance calculation program of the aero-engine, and the thermal performance analysis of the aero-engine under air cruise conditions is carried out based on the turbine’s internal burner technology. It can be concluded that the turbine’s internal burner technology will significantly improve the thermal performance of the aero-engine, and at the same time, the increment of TSFC can be ignored.

Aiming at the problems of insufficient refinement and low efficiency of aircraft ground centralized deicing operation under snow and ice weather, a description method of aircraft ground centralized deicing operation process based on a spatiotemporal correlation network was proposed. Based on the allocation and spatiotemporal distribution of airport deicing resources, a colored spatiotemporal network model was established to describe the dynamic process of aircraft ground deicing through the evolution of a colored spatiotemporal network. A resource optimization method was designed. The traditional genetic algorithm was improved by Sine chaotic mapping technology and differential evolution, and verified by experiment. The results show that the root-mean-square error of the idle time of each deicing site is 18.29 after optimization, which is 4.88 less than before optimization, suggesting that the utilization rate of the deicing site is increased by 21.06%. The improved NSGA-II algorithm can increase the completion rate of deicing potential resource allocation by 7.62% and has a faster convergence rate compared with the traditional algorithm, which proves the feasibility of the proposed method.

In the field of electronic information science, with the continuous advancement of signal processing technology, filtering technology has become particularly important due to its ability to effectively suppress noise and extract useful information. This article focuses on exploring an innovative method for rapid optimization of filters. By designing a hollow cylindrical dielectric ceramic and combining it with traditional inductive structures, the bandwidth and return loss characteristics of intelligent filters at various frequencies could be quickly controlled. Simulation results show that by loading the dielectric ceramic, the bandwidth of filter 1 is reduced by an average of 20%, the return loss at low frequencies is increased by an average of 3 dB, and the return loss at high frequencies is reduced by 5 dB. Simulations were conducted on two different structures of filters, and the results showed that the optimization design technique has good applicability.

This paper introduces a radar sensing early warning system designed and implemented based on CYCLONE IV series FPGAs, which generates PWM signals to control the rotation of servo through parallel high-efficiency FPGAs, and at the same time generates trigger signals to drive the ultrasonic radar to detect obstacles, and if the set distance is reached, the buzzer will sound an alarm, and display the current servo angle and distance to the obstacle through the LCD, so as to achieve the effect of radar early warning—radar warning effect.

Laser communication technology with characteristics of large communication capacity, high communication rate, low power consumption, and strong anti-jamming ability, shows great advantage on satellite communication. Meanwhile, the stability and uniformity indexes of the temperature of the laser antenna must be strictly controlled in order to ensure communication duration and quality. This paper proposes an expanded configuration layout and heat radiator + heat pipe type thermal control design scheme, takes a DFH-4E platform satellite laser terminal design scheme as an example, and carries out modeling verification using mechanical analysis and thermal analysis software. The analysis results show that the temperature of the optical mirrors can be limited to 20±4 °C, and the temperature gradient of the telescope tube stabilizes within 2°C/100mm.

Systems Modeling Language (SysML) is a standard modeling language commonly used in the field of systems engineering. As one of the key elements in SysML, The “use case” not only serves as an important means for refining requirements but also drives the incremental design process of the entire model. Taking the design modeling of remote-sensing satellite systems as an example, this paper introduces an incremental iterative method based on use cases in the system model construction of spacecraft, which continuously evaluates architecture-related aspects such as requirement coverage, satisfaction degree, as well as the result of investment during production, manufacturing, and operational phases. At the same time, it realizes the digital collaborative system-level design of spacecraft.

Most materials have a lower ignition point than air under oxygen enrichment conditions and are more likely to burn, while the oxygen enrichment and high-pressure environment in oxygen systems provide easy combustion conditions. The fire of the oxygen system on the aircraft is difficult to control and may lead to catastrophic events, so the fire risk of the oxygen system and components should be fully considered in the whole process of oxygen system design and verification, and the possibility of fire should be reduced as far as possible by selecting appropriate materials and carrying out reasonable design. In this paper, a set of oxygen system fire risk analysis methods is proposed, which is introduced from three aspects of external risk, internal risk, and system design considerations, and design suggestions are given for typical factors leading to fire, which provides a reference for the design and safety analysis of civil aircraft oxygen system.

Aircraft powered by electric motors are becoming an important development direction in the aviation market. High power-to-weight ratio and high-efficiency electric motors dramatically increase the energy utilisation efficiency of the aircraft, and the development of high-performance electric motors for aviation is a key link in the green development of the aviation industry. The design of high power-to-weight ratio and high efficiency motors is the basic support for the development of electric propulsion aircraft. In this paper, a 200 kW non-uniform Halbach array inner-rotor permanent magnet synchronous motor is taken as the basis for design, and a multi-objective genetic algorithm is used to optimise its design. The main objective of the study is to optimise the geometric parameters of the motor to maximise its efficiency of the motor while reducing the weight of the motor, with the temperature rise of the windings not exceeding 160°C. Through electromagnetic and thermal simulation analysis, the optimised motor shows a significant improvement in efficiency, torque density and power density, and effectively reduces weight while increasing overall performance, verifying the feasibility and effectiveness of the optimisation strategy.

This paper aims to investigate the fire resistance performance of crucial components in an aero engine, focusing on a representative mounting joint. A streamlined model of the mounting joint is tested using a standardized burner to produce a uniform flame, replicating severe operational environments. Precise measurements are implemented to track and document real-time variations in vital indicators such as surface temperature and strain. The study delves into the characteristics of wall temperature and stress distribution at specific points within the structural elements, considering various flame impact positions, installation techniques, and static loading conditions. The results provide critical insights into the fire performance of the mounting joint, demonstrating significant variations in axial temperature distribution and stress levels under different conditions. These findings furnish data-driven evidence supporting the fireproof airworthiness compliance of the engine’s mounting joint, highlighting the joint’s resilience and stability under extreme conditions.

The space orbit resources are becoming more and more limited due to hundreds of thousands civil spacecrafts being planned for future space missions. As of 2024, polar orbit at altitude of about 1200 km remains to be one of virginal spaces. A constellation for future space-based communication can be deployed in such a space. For purpose of simulation, an orbit is assumed at epoch of Jan. 1, 2025, and the orbit elements are as following: semi-major axis is 7578 km, inclination is 90deg., the eccentricity is 0. The mission is assumed to last 15 years. With the help of professional software SPENVIS, authors have carried out simulations. Results have shown that the total radiation dose is about 109Krad if 3 mm Aluminum shielding is considered, and total radiation dose reaches 45Krad if 6 mm Aluminum shielding is considered, total radiation dose can reach 35Krad if 9 mm Aluminum shielding is considered. According to the space environment simulations and a priori space engineering experience, 9 mm Aluminum shielding is recommended to be one of the S/C design constraints if future communication constellation is to be deployed at altitude of about 1200 km.

Postoperative rehabilitation of stroke patients requires a large amount of repetitive training, and in the face of the huge demand for treatment, how to efficiently and accurately carry out rehabilitation has been an important part of research in medical devices. The article analyses the upper limb activities of a rehabilitation robot from an orthokinetic perspective. In order to investigate the angle change of the upper limb joints when drinking water, MATLAB was used to build a robot motion model to simulate the trajectory of the upper limbs when drinking water. Through the simulation results, it can be observed that the angular velocity of the shoulder joint of the rehabilitation robot increases and then decreases from 0 s to 8 s, with the maximum angular velocity of 0.35 rad/s at 4 s, and the angular acceleration increases and then decreases and then increases and then decreases, with the maximum angular acceleration of 0.13 rad/s² at 1.7 s and 6.3 s.

To satisfy the needs of marine environmental monitoring applications for shipborne unmanned aerial vehicles (UAVs), this study developed a small long-endurance vertical takeoff and landing (VTOL) UAV specifically for shipborne applications. The proposed UAV featured a Blended-Wing-Body (BWB) design, and its aerodynamic design was investigated and improved. Emphasis was placed on improving aerodynamic performance, including increasing the lift-to-drag ratio, reducing the impact of the pitchdown moment, and improving the aircraft’s directional stability. Combined with the form of vertical takeoff and landing, VTOL equipment with a fin-shaped landing gear was proposed to improve the aircraft’s directional stability. The results indicate that the improvement achieved a 4.13% increase in the lift-to-drag ratio and a 30.1% increase in the directional static stability derivatives.

This study conducts simulation research on the performance of utilizing weak GNSS signals for autonomous orbit determination of Low Lunar Orbit (LLO) spacecraft. The models of orbits, clocks, and measurements are derived and the autonomous orbit determination performance is accessed by Monte-Carlo simulations. The results show that the position estimation accuracy of an LLO spacecraft at a height of 100 km can reach 40 m by using a 15 dB gain antenna paired with a 15 dB-Hz high-sensitivity receiver. The orbit determination accuracy can reach approximately 23 m with a high-precision lunar gravity field model configured in the filter, which demonstrates the application prospects in both real-time and postprocessing orbit determination of lunar orbit spacecraft.

A shock environment is one of the harsh dynamic environments that spacecraft need to experience throughout the entire life cycle. The units on the satellite need to withstand the shock load generated by unlocking the pyrotechnic release device. The pyrotechnic shock has the characteristics of high frequency and high amplitude, with a general duration of action within 20ms, a frequency above 1kHz, and an amplitude of 100 g to 3×10⁵ g. However, in-ground tests, vibration tables, and mechanical shock testing are commonly used for shock tests, which are different from the pyrotechnic shock load in satellites. In this paper, a shock response data analysis of pyrotechnic unlocking of the solar array unlocking is presented. The shock attenuation characteristics of the satellite unit are obtained and compared with the characteristics of the level shock test. The results indicate that for the unit in the near-field and midfield of the shock source, significant attenuation can be observed throughout the entire range of the shock response from the mounting position to the bottom of the units in the satellite-level shock test, while significant attenuation can only be observed above 3000Hz in the ground test. For the same magnitude, the shock environment of the unit-level test may be more severe than the satellite-level test. The difference between the satellite level and unit level can be considered when formulating the shock test conditions.

In this paper, a variable configuration amphibious robot is designed and analyzed, which can move freely on both land and water. The amphibious robot’s water-land switching mechanism is studied and the folding mechanism of the front and rear hydrofoil is designed. The NACA0012 aerofoil with a high lift-to-drag ratio is selected. The installation position and angle of the front and rear hydrofoils are studied based on the RANS method. A numerical parameter model of the amphibious robot is established using the Kriging model. The NSGA-II Genetic algorithm is adopted to optimize the robot’s hydrodynamic characteristics.

In order to realize the lightweight of spinning bikes, ANSYS was used to analyze the static characteristics of the support frame of the spinning bike. The height, length, and thickness of the support frame were analyzed sensitively. Finally, the support frame structure was optimized based on the response surface method to obtain the optimal scheme. The results show that the optimized support frame meets the design requirements. The equivalent stress is reduced by 4%. The weight of the support frame is reduced by 6%. The deformation is reduced by 8%, and the optimization goal is achieved.

The shape layout of the wing largely determines the endurance of the UAV. Aiming at the aerodynamic layout characteristics of tandem wing unmanned aerial vehicle (UAV) with overlapping wings and tandem front and rear wings, the influence of layout parameters such as wingspan size and normal spacing on the lift and drag characteristics of tandem wing is analyzed. According to the appearance characteristics, the tandem wing is divided into three types of layout, and the lift drag characteristics of each layout under different normal spacing of front and rear wings are calculated by vortex element method, and the characteristics of the aerofoil such as streamline are further analyzed. It is found that when the front wing size is larger than the rear wing, the best lift-drag ratio and drag characteristics are often brought about. When the front wing size is smaller, the lift coefficient is favorable. When the front wing size is the same, the wingtip vortex coupling will cause the lift drag characteristics to decrease. Therefore, the influence of the front wing on the rear wing in tandem wing layout design is often a factor that cannot be ignored. The study of the layout design law of the front and rear wings has important guiding significance to improve the aerodynamic performance and even the endurance of the tandem wing.

In this paper, a bi-directional self-propelled linear piezoelectric actuator is designed. The linear actuator consists of a capsule-shaped metal vibrator and piezoelectric ceramic pieces, and the second-order and third-order bending vibration modes are excited by excitation of the piezoelectric ceramic pieces on both sides of the metal vibrator, thus realizing the bi-directional motion of the motor. Mathematical modeling and finite element transient dynamics analysis of the ultrasonic motor are carried out based on the analysis of the kinematic mechanism of the linear actuator. The simulation data verify the feasibility of the scheme.

To analyze the dynamic stability of helicopters in real flight environments and understand the influence of key flight state parameters on dynamic stability, the six-degree-of-freedom equations of helicopter flight dynamics and the small disturbance principle are utilized. The flight test is used to obtain the variations in motion parameters after the helicopter is disturbed. A parameter identification method is then employed to solve the motion equations, yielding the oscillatory mode parameters that characterize the helicopter’s dynamic stability. Sensitivity analysis of the dynamic stability parameters under different flight states is conducted based on this method. The results indicate that a helicopter’s dynamic stability is closely related to its flight weight, center of gravity, speed, and flight mode. Under hover and forward flight conditions, the influence on longitudinal and lateral dynamic stability varies.

In this paper, an active control method based on unilateral magnetic flux notch filter is proposed. Magnetic flux difference notch filter is an active control method with good effects. However, in the actual operation process, the magnetic sensor may be damaged or discharged for various reasons. This paper studies whether the unilateral magnetic flux notch filter can still maintain a good control effect. The simulation results show that the attenuation speed of the synchronous-frequency vibration in the magnetic force will be slower than differential notch control, but it is still obviously better than the force estimation control.

Through fault diagnosis, the location and cause of failures can be rapidly identified, thereby contributing to reduced downtime for maintenance. Currently, fault diagnosis methods are unable to describe dynamic failure relationships and require precise data for functionality. Therefore, this paper proposes a fault diagnosis method based on the integration of T-S fault trees (TSFTs) and Bayesian networks (BNs). Firstly, the fault modes for analysis are determined. The scope and boundaries of the analysis are defined. Then, using TSFTs, the fault mode is set as the top event. All causes leading to the fault are analyzed and designated as intermediate and basic events. The dynamic relationships between fault causes and fault modes are described using T-S dynamic gates. Secondly, the top, intermediate, and basic events, along with their dynamic relationships, are converted into leaf nodes, intermediate nodes, root nodes, and directed edges. On this basis, a directed acyclic graph (DAG) of the Bayesian network is constructed. Finally, based on the DAG, combined with the action rules between nodes, failure probabilities of the root nodes, and the Bayesian network’s backward reasoning algorithm, the importance of the root nodes is calculated. Based on this information, targeted improvements are made to the fault modes. At the end of the paper, an electromagnetic brake is used as an example to demonstrate the calculation process of the proposed method.

A hierarchical sliding mode control (HSMC) method incorporating friction compensation and a nonlinear convergence law is proposed to address the nonlinear friction problem in flexible joint space manipulators. First, an adaptive friction compensator is introduced to estimate friction. Next, an observer is designed to assess the error in the friction model. Friction compensation is achieved by integrating the adaptive friction compensator with the friction model error observer. A first-order sliding mode surface is then constructed by using the reducer output angle and joint angle, with a second-order sliding mode surface derived from a linear combination of the first-order surfaces. A nonlinear convergence law is integrated into the control scheme, enabling the system to adapt to changes in the sliding surface, thus maintaining control performance and reducing system chattering. The convergence of the manipulator’s joint trajectory tracking error is ultimately proven based on Lyapunov’s theory. Simulation results demonstrate that the proposed control method effectively compensates for friction and enables the flexible joint manipulator to track the desired position trajectory within a finite time.

Due to the high-speed relative motion of satellites in the interstellar link, signals exhibit dynamic characteristics during transmission. This article proposes a dynamic characteristic simulation technology for inter-satellite link signal transmission. Based on the inter-satellite link signal system simulation technology, it realizes the simulation of Doppler dynamic characteristics, power dynamic characteristics, and range forwarding dynamic characteristics in inter-satellite links, thereby more accurately simulating the transmission characteristics of inter-satellite link signals. This provides an environment for satellites (spacecraft) to conduct ground simulation tests before officially connecting to the inter-satellite link, ensuring the correctness of their functions, performance, and interfaces.

Nowadays, composites are more and more widely used in civil aircraft structures, and the influence of temperature effects on airframe structures cannot be ignored. For the assessment of temperature effects in civil aircraft fatigue and damage tolerance, the types of temperature missions are defined. Around the expected routes of civil aircraft, the temperature data of the expected routes from 2012 to 2017 were collected, and the weekly average temperature of each route was statistically calculated by using a big data processing algorithm. Based on the definition of typical temperature mission types, the expected routes were categorized, and the temperature mission types of civil aircraft and their ratios were determined, which provides support for the fatigue and damage tolerance assessment of civil aircraft and guarantees the environmental adaptability of civil aircraft operation.

In recent years, the development of low-orbit constellation systems tends to form large constellations with short transmission delays and wide coverage areas. In view of the difficulty of complex design to maintain the high reliability of a single satellite when constructing a constellation of micro-satellites, this paper analyzes the availability of the constellation based on careful consideration of the backup strategy of the low-orbit constellation. Based on the METRIC model, two evaluation indicators are established, namely, the guarantee rate of the constellation backup satellite and the expected cost of implementing the backup strategy. The optimal constellation backup strategy is selected to achieve the goal of maintaining the availability of low-orbit constellations at low cost. Taking a Walker constellation as an example, the results show that the probability of the low-orbit constellation being in the state of a trouble-free satellite is very low when there are more working satellites, while the large low-orbit constellation with a certain number of faulty satellites still has a service performance that cannot be ignored. The evaluation model established in this paper provides a foundation for further analyzing the availability of satellite constellations and optimizing the backup strategy from the perspective of backup strategy.

With the continuous development of the civil aviation industry and the increasingly busy global civil aviation transportation, the civil aviation field has put forward higher requirements for the navigation quality of aircraft in complex environments. Multi-GNSS navigation has become an important solution to improve the accuracy, stability, and availability of aircraft navigation. In November 2023, the latest revision of Annex 10 to the Convention on International Civil Aviation, which contains the standards and recommended measures for BDS, officially came into effect, marking the recognition of BDS by the International Civil Aviation Organization and becoming a universal satellite navigation system for global civil aviation. Dual frequency dual system navigation technology has advantages such as redundant systems to improve safety and dual frequency positioning to improve accuracy, which can provide support for fine air management. Therefore, BDS and GPS, as the two major satellite navigation systems, jointly undertake the mission of further improving the accuracy and stability of aviation navigation. In response to the navigation needs in the civil aviation field, firstly, the BDS and GPS combined satellite-based navigation technology was studied, and the application status and technological advantages of the combined satellite-based navigation technology were analyzed; Then, the positioning principle of combined satellite-based navigation was analyzed, and the key technologies of combined satellite-based navigation were proposed. Finally, the future development trends of civil aviation satellite navigation technology were summarized, aiming to provide reference and inspiration for relevant research and practice in the field of civil aviation in the Asia Pacific region.

The proposed multi-factor analysis method for line-of-sight measurement error in spaceborne observation platforms is based on the transformation relationship between the target and the image plane of the spaceborne optical sensor. Through establishing a target observation model, various sources of error in the line-of-sight measurement process are analyzed, revealing the relationship between line-of-sight measurement errors in the Earth-centered inertial coordinate system and satellite attitude measurement errors, camera calibration errors, and target perception errors is derived theoretically. Monte Carlo simulation experiments validate the effectiveness of this theoretical analysis method, and the analysis conclusions can provide a reference for engineering applications.

The Mozi satellite is one of the space projects sponsored by the Chinese Academy of Sciences; its goal is to carry out quantum communication at space scale. Based on recent orbit elements for the Mozi satellite, SPENVIS software will be used to carry out space environment assessments for the Mozi satellite in the coming two years. During the simulations, effects due to trapped proton, trapped electron, solar proton, and cosmic rays are considered. Such characteristic features as Total ionization dose, non-ionization displacement damage, LET spectrum, and atom oxygen are simulated in detail. Simulations have shown that Mozi’s space environment will be acceptable during the coming two years. Such a situation will help to support surplus space experiments in the future.

Storage and maintenance is one of the most important tasks in the whole life of civil aircraft, which is directly related to the product’s quality and reliability, and affects the mass-produced schedule, maintenance cost and delivery quality of aircraft. The reasonable, standardized storage and maintenance work may effectively reduce the cost of warehouse maintenance and improve the quality and reliability of finished products. According to the civil aviation standards and experiences, from the storage environment, storage management, maintenance interval and maintenance tasks, this paper sorts out the storage and maintenance elements comprehensively, identifies storage failure modes, influence factors and storage reliability analysis process, and puts forward storage mathematical model and improvement measures, so as to provide strong support for the storage and maintenance of civil aircraft finished products.

This paper deals with the optimization of flight arrival and departure sequencing in a multi-airport terminal area, addressing the pressing challenge of escalating flight delays. A two-tiered scheduling intervention-stochastic queuing bi-level model is established, which includes both strategic and tactical levels while considering multiple factors. A genetic algorithm based on multi-waypoint rolling horizon control is developed to search for Pareto optimal solution sets to optimize flight scheduling. Experimental validation shows that, compared to the pre-optimization conditions and the traditional First-Come-First-Served model, the proposed method significantly reduces the total flight delay time and effectively promotes the optimal allocation and efficient utilization of airspace resources in the terminal area.

The Remaining Life Prediction of the aeroengine is an important link to realize health detection in maintenance based on condition. To improve the prediction accuracy of the Remaining Useful Life (RUL) of the aero engine, the grid search method is adopted to optimize the hyperparameters in the traditional data-driven life prediction algorithm. In the process, it is easy to fall into problems such as local optimization and high dimensional redundancy characteristics with long life data of aero engine and strong sequence. An improved Hunter Prey Optimizer (HPO) is proposed to optimize the Temporal Convolutional Network (TCN) model THPO-TCN. By constructing causal convolution to capture the high-order timing features of fused multi-sensor data, and using expansive convolution to ensure the capture of the medium and long-term dependencies of the time series, the quality of the initial solution of the global optimization algorithm HPO is guaranteed by using chaotic initialization method (Tent). Then the HPO algorithm is improved to find the optimal hyperparameters of the TCN temporal network by introducing refined reverse population and Gaussian variation strategies. The results of aero engine degradation simulation data show that the proposed THPO-TCN network structure model has a significant advantage over TCN, LSTM, GA-TCN, and the unimproved HPO-TCN network model in the prediction accuracy of engine residual life.

At present, the deployment of obstacle avoidance nodes of overhead transmission lines in the airport clearance protection area is generally set in a decentralized manner, and the coverage of obstacle avoidance is limited, which leads to the difficulty of the final optimization results of obstacle avoidance to meet the expected standards, and the cost of obstacle avoidance increases. Therefore, the design and analysis of the optimization method for obstacle avoidance of overhead transmission lines in the airport clearance protection area based on the GSA algorithm are proposed. According to the current optimization requirements, the multi-step method is adopted first to break the limit of obstacle avoidance coverage and complete the multi-step deployment of obstacle avoidance recognition nodes and obstacle feature collection. Based on this, the GSA calculation optimization model for obstacle avoidance of overhead transmission lines in the airport clearance protection area is constructed, and the adaptive navigation path planning correction method is used to optimize obstacle avoidance. The test results show that compared with the deployment method of high-voltage transmission lines and the obstacle avoidance optimization of typical cross-coupled transmission lines in the improved YOLOv5, the GSA algorithm in this design finally obtains fewer obstacle avoidance costs for overhead transmission lines in the airport clearance protection area, which indicates that the cost of obstacle avoidance processing has been effectively controlled with the help and support of the GSA algorithm. The specific effect has also been verified in practice.

This study proposes a feed-forward neural network (FNN)-based remote fault detection system for mechanical equipment, aiming to identify potential faults early by monitoring and analyzing equipment operation data in real time. The system collects data through sensors, and after preprocessing and feature extraction, the FNN model is used for training and fault diagnosis. Experimental results show that the system can effectively improve the accuracy and efficiency of fault detection and support intelligent maintenance of industrial equipment. This study proposes a feed-forward neural network (FNN)-based remote fault detection system for mechanical equipment, aiming to identify potential faults early by monitoring and analyzing equipment operation data in real time. The system collects data through sensors and uses FNN models for training and fault diagnosis after preprocessing and feature extraction. The experimental results show that: The average response time based on the algorithm experiments is less than 120 ms, and the false alarm and missed alarm rates remain low at 0.4% and 0.2%, respectively, which indicates that the system has a high accuracy in distinguishing between normal and faulty states.

In this study, a voltage-based IEPE (Integral Electronics Piezo-Electric) circuit is designed for vibration monitoring, which achieves simple signal transmission and strong anti-interference capability through a two-wire design. In this study, the dynamic AC characteristics and impedance matching characteristics of the circuit are comprehensively analysed by combining a low-frequency small-signal model and a simulation tool. The dynamic AC characteristics of the circuit are analysed by theoretical calculations; the frequency response flatness and output impedance of the circuit are evaluated by using the Multisim simulation tool. The experimental and simulation results show that the key factors affecting the output impedance of the circuit are highly consistent with the theoretical calculations, which verifies the accuracy of the analysis. The circuit meets the requirements of a typical vibration monitoring IEPE circuit in the 10 Hz to 20 kHz range, with excellent frequency response characteristics and an output impedance of 83 Ω. In addition, the circuit has the advantages of a two-wire system and high input impedance, which provides a reliable theoretical basis and practical support for the optimisation of vibration monitoring circuits in aerospace electromechanical systems.

Space Variable Objects Monitor (SVOM) satellite was sent into its orbit in late Jun. 2024. Its mission object is to detect and position Gamma Ray Burst in the sky. There are 4 payloads onboard the SVOM,including ECLAIRs, MXT, GRM and VT. Main orbit elements are presented and analyzed based on internet sources since SVOM’s deployment in space. SPENVIS is an advanced software, which is open to registered users and can provide reliable simulation results. The authors are team members of SVOM, who have access to quickly available and high precision orbit. These two advantages make it possible to have quick and precise analyses of orbit and its space environment. SPENVIS software is employed to make space environment simulations for SVOM. Earth radiation belt, solar radiation, and galactic cosmic rays are taken into account during the simulations. The dose of radiation is simulated, too. All the simulation results are valuable constraints, which will support in-orbit testing of SVOM during the first 6-month testing.

Due to the customized design of high-speed bus protocols used by different aircraft designs, there are many kinds of high-speed bus protocols for flight test. Currently, one test system can only collect data on one kind of bus protocol, which puts great pressure on the allocation of test resources. In this paper, the reconfigurable testing technology of multi-type high-speed buses is studied concerning the architecture requirement of a software-defined system. Firstly, the universal heterogeneous platform of the high-speed bus test system is designed, the data communication model between heterogeneous processors is established, and the hardware platform and software system are decoupled. Then, the protocol domain mapping model is established to realize the unification of different protocol data parsing algorithms. The parallel retrieval technology with addressable content is designed to realize the independent retrieval of data and meet the requirements of synchronous collection. Finally, the experimental verification shows that the technology can realize the rapid reconfiguration of equipment functions, enhance the interchangeability of test equipment, and ensure the effectiveness of flight test mission scheduling.

Gyroscope bias will affect the stability accuracy and pointing accuracy of the gyro-stabilized platform, so it is usually necessary to calibrate it regularly or even dismantle it to calibrate. Low-cost gyroscopes are particularly affected by temperature and other environmental factors, and their bias may also drift when they work continuously for a long time. However, the servo of an air-launched missile seeker is often powered on in the air, and there is no opportunity for static calibration, so it is necessary to implement dynamic bias calibration in the motion environment. In this paper, a dynamic bias calibration method for the low-cost gyro-stabilized platform on an air-launched missile is proposed, which uses the low-frequency and high-precision attitude data output from integrated navigation on the carrier to calibrate the bias of gyro-stabilized platform. The algorithm represents attitude error through quaternions, forming a closed loop between bias and attitude error, and incrementally correcting the bias value in the working process. Experiments under different working conditions have shown that this method can gradually suppress the influence of gyro bias in motion environments, achieve maintenance-free, and allow the use of lower-cost gyroscopes in design, which is of great significance to reduce the volume and power consumption and cost of the seeker.

Space manipulators and ground cooperative manipulators exhibit dynamic differences, including the effects of zero gravity, the lower joint stiffness of space manipulators, their slightly weaker dynamic response characteristics, and the fact that they are often considered to have floating bases. These differences result in higher control difficulty for space manipulators compared to ground manipulators. At the same time, due to the limitations of in-orbit hardware computing power, the recognition cycle of visual positioning algorithms is long, making mobile target grasping one of the most challenging tasks for space manipulators. Joints are the core components of space manipulators. Solving the problem of joint jamming and preventing the normal use of space manipulators can effectively improve the service life and quality of space manipulators in orbit. This paper proposes a deep reinforcement learning-based method for executing mobile target capture tasks when a single joint of a space manipulator becomes stuck and loses one degree of freedom. In a simulation environment, a model of a faulty space manipulator is built. Dynamic characteristics and signal delay conditions that are close to the real state are input to train the mobile target capture task. The obtained model meets the requirements of task implementation in the simulation environment.

To address the challenge of insufficiently considering dynamic characteristics (magnitude-phase frequency characteristics) in the PD parameter design of electromechanical servo systems, this paper proposes a PD design method focused on dynamic characteristic indicators. Firstly, a ninth-order transfer function (TF) model of the electromechanical servo system is established based on the dynamic equations. Subsequently, the Routh-Hurwitz criterion and the relationship between TF coefficients are employed to supplement the system’s stability constraints and the compatibility constraints of TF coefficients, ensuring stability and compatibility during the PD design process. Building on this foundation, an improved rational fractional polynomial method is utilized to identify the coefficients of the TF model based on the concept of parameter identification, enabling the rapid determination of PID parameters that meet dynamic characteristic indicators, thereby enhancing design efficiency. Furthermore, by adjusting requirements data, multiple sets of controller parameters that satisfy the original requirements can be identified. Simulation results demonstrate that the designed PID parameters not only meet the requirements of dynamic characteristic requirements but also consider system stability and the compatibility of TF coefficients, showing good agreement with the experimental results.

This paper addresses the need for anomaly detection in flight telemetry data, proposing a novel model based on LSTM-attention-VAE. This model leverages the strengths of LSTM in handling sequential data, attention mechanisms in extracting key features, and VAE in learning data distributions to effectively identify anomalies in flight data. Experimental results demonstrate the model’s superior accuracy, precision, and F1 score in flight data anomaly detection tasks, offering significant advantages over traditional algorithms. This research contributes a new and effective method to the field of flight data anomaly detection, with the potential to support flight safety.

Rapid and accurate simulation of aircraft wake evolution under crosswind conditions and measurement of wake vortex encounter safety are crucial for identifying hazard zones and reducing flight intervals. Based on numerical simulation results, this paper constructs a three-dimensional wake vortex danger zone based on aircraft pairing under crosswind conditions, accurately calculating wake vortex dissipation and danger zones. The H-B model initializes the wake vortex velocity field, and the SST k ? ω turbulence model in Fluent software simulates wake vortex evolution under different crosswind strengths. The adaptive mesh technique improves computational accuracy, combined with induced rolling moment coefficients, to assess the severity of wake vortex encounters and delineate danger zones. Results show that side wind increases the decay rate of the wake vortex and reduces the extent of the danger zone. The danger zone shifts horizontally and vertically with increasing side wind intensity, scaling down the current longitudinal spacing of the ICAO wake flow according to side wind magnitude and providing vertical and lateral separation.

GNSS-LEO occultation detection is widely used in radio-sounding, climate research, and space exploration because of its global coverage and high vertical resolution. The traditional occultation event prediction method has the problem of high computational cost, while this study reduces the computation time and improves the accuracy by adaptively adjusting the time step. Experimental results show that the adaptive time-step algorithm significantly improves the efficiency of predicting occultation events compared with the Brute-force solution method in the application of different satellite constellations.

The long shallow cavity is a common structural form of the bomb bay of aircraft weapons. When the long shallow cavity flows through at high speed, strong noise will be generated inside the cavity, the noise includes cavity resonance and broadband random noise, and the total sound pressure level can reach more than 170 dB. In this paper, two effective noise suppression methods are proposed, namely the leading-edge spoiler and the trailing-edge inclined plate. The peak noise is reduced by 5.9 dB and the total sound pressure level of broadband noise is reduced by 4.4 dB, and the effect is significant. When the hatch is opened, the total sound pressure level of the noise load is more than 170 dB, which brings a harsh noise environment to the weapons and equipment loaded inside the bomb bay ^[1-5]. So, the noise load suppression of the embedded bomb bay has become a problem that must be considered in the design of the aircraft structure. Considering that the structure of the embedded bomb bay is a long and shallow cavity, and there are two different noise loads, cavity resonance and broadband random noise, how to effectively reduce the resonance sound and broadband random sound of the long and shallow cavity has become a problem that many scholars are committed to solving.