Aiming at the high temperature environment of the attitude control solenoid valve, the affected performance of the valve is simulated and analyzed. At the same time, the high temperature experiment of the valve is carried out. The results of simulation analysis and high temperature experiment indicate that the moving distance of the armature reduced due to the Non-metallic expansion of the core at high temperature, which causes the valve unable to open normally. And with the swelling effect of the oxidant to the core, the reliable operation temperature of oxidant valve is lower than fuel valve. By taking measures of enlarging the moving distance and replacing the core material to PFA, the high temperature environmental adaptability of the solenoid valve is improved.

In response to the application background of satellites passing over or observing a ground target within a specific time, the Walker constellation scheme design is carried out for meeting the revisiting time requirements. The models of a satellite coveraging a ground target are constructed. The methods for calculating the time-windows of a satellite passing over a ground target, and onboard circle/rectangular-field-of-view sensor observing a ground target are designed. On this basis, a Walker constellation scheme design algorithm which satisfies the revisiting time requirement with the minimum satellite number is developed. The simulations and analyses are provided for three simulation scenarios. The results of the developed algorithm are compared with STK, and the average error of revisiting times is less than 1.1 s, which verifies the accuracy and rationality of the models and the algorithm. The relevant research results can provide reference for the design of Earth observation constellation schemes.

To achieve the design goals of high performance and reliability of propulsion systems for attitude control in the future, study on the dynamic characteristics has important scientific and engineering value. The dynamic simulation method for the MMH/NTO dual component propulsion system for attitude control is studied based on AMESim software. Firstly, the dynamic models of each components are determined and their simulation modules are established based on the system scheme. Secondly, the simulation model of each component is built by the AMESim software and the simulation model of the whole system is established. Finally, the processes of tank pressurization and multi thrust chamber pulse and interactive working are simulated. The changes in key parameters like pressure and flow rate of the thrust chamber are analyzed and the modeling method is verified. Meanwhile, the stability of the check valve is analyzed. The influences of working parameters and structural parameters on the stability of the valves are discussed. The results indicate that the dynamic simulation model established in this study can be used to accurately simulate the processes of multi thrust chamber pulse interaction. The inlet pressure and the throttle area of the check valve have an obvious impact on the stability of the system. The dynamic simulation method can be used for dynamic characteristics and stability analysis, which can provide useful references for the system scheme design and dynamic characteristics study.

As an important component of aviation control and power systems, the suction characteristics of DC electromagnetic coils used in aviation valves are a key factor in the design of electromagnetic coils. Taking the magnetic-proof ring magnet in the DC magnets for aviation valves as the research object, the magnetic-proof ring magnetis modeled in ANSYS Maxwell and the magnetic field distribution is given. The effects of different air gap, different parameters and armature length of the magnetic-proof ringon the suction characteristics of the electromagnet are analyzed. On this basis, two optimization methods are applied to the multi-objective design of the suction force at different positions of the electromagnet. One is to use the orthogonal test method to carry out the primary and secondary analysis of the factors that affect the suction force characteristics of the electromagnet more obviously. The other is to use the optimization software optislang to carry out the sensitivity analysis of the factors and the optimization design based on the evolutionary algorithm. Finally, a comparative analysis of the improvement effect of the two pairs of methods on the suction characteristics is carried out. The results show that optislang optimization is more in line with the requirements of electromagnet suction.

Torque limiter is a physical protection device that ensures mechanical equipment operates under safe load conditions. Conventional engineering design typically employs static design and verification methods, with optimization and iteration carried out through physical prototypes, resulting in long development cycles and high costs. The design simulation and combination parameter optimization of a miniaturized torque limiter for a specific model are focused on. Firstly, based on the principle and elements of the steel ball's inclined surface disengagement, some mathematical formulas are established and a three-dimensional structure is designed, identifying the key parameters affecting the performance of the torque limiter. Secondly, the torque transmission characteristics and structural strength of the torque limiter are simulated, and the accuracy of some strength simulation results is verified by using Hertz contact theory. Thirdly, the main structural parameters are optimized and evaluated by using the orthogonal experiment method, obtaining the best parameter combination. Finally, two principle prototypes are produced based on the models before and after optimization, and static disengagement experiments are conducted to verify the accuracy of the disengagement torque under static load.

Permanent magnet synchronous motor (PMSM), owing to its high power factor, high efficiency, and high power density, have been widely employed in aerospace vehicles to enable high-dynamic servo motion. However, during long-term tracking control or attitude holding, PMSMs are prone to interturn short-circuit faults (ITSC). Under servo operating conditions, the fault signals exhibit non-periodic characteristics in the time domain, which poses considerable challenges for fault diagnosis. To address this issue, an ITSC diagnosis method is proposed based on the high-frequency negative-sequence current. First, a simplified analytical model of PMSM with ITSC faults is established to reveal the characteristic impacts of the fault on electrical quantities. Second, a high-frequency voltage signal is injected into the control system, and the high-frequency current response of the motor is extracted through a band-pass filters. Finally, the negative-sequence component of the high-frequency current is calculated as the diagnostic indicator, enabling real-time fault identification. By employing the high-frequency negative-sequence current as the fault feature, the proposed method can effectively distinguish healthy and faulty states of the motor under servo conditions, while improving both diagnostic speed and robustness. Simulation results demonstrate that the proposed method achieves reliable diagnosis under servo operating conditions with rapid variations in position, speed, and load, with a diagnostic time of less than one fundamental cycle, showing strong potential for engineering applications.

In order to meet diverse mission requirements and reduce design and production costs, modular design has become an important development direction for flight vehicle system design. For modular flight vehicle, general components are key components and also the primary prerequisite and important foundation for carrying out modular design. To address the problem of poor module universality in traditional flight vehicle design, a general component construction method based on self-organizing mapping neural network is proposed. Firstly, the characteristics and content of modular flight vehicle design are introduced. Secondly, in response to the problem of long computation time and easily getting in the local optimization in self-organizing mapping algorithm, the calculation process for the general component construction method combining self-organizing mapping and neural network is proposed. Finally, simulation experiments are conducted using a modular flight vehicle design example to validate the proposed general component construction method. The results show that the method can effectively meet the requirements of modular flight vehiclegeneral component construction, and significantly improve computation time and solution accuracy compared to a single self-organizing mapping algorithm.

The cryogenic exhaust valve is a key component of the liquid rocket propulsion system, and the main failure mode is the stuck guide. To improve its action reliability, a "metal-nonmetal" composite guiding structure is proposed. The non-metal hot pressing forming process is studied, and the theoretical calculation and simulation analysis of the guiding clearance variation under low temperature are carried out. An experimental system is built to verify the reliability of the forming process of the composite guiding structure and the rationality of the clearance calculation. The research results show that the nonmetal composite guiding structure of the cryogenic exhaust valve can adapt to the low temperature operating conditions, and has higher action reliability and tolerance to contaminants.

Research advances in fluid-structure interaction (FSI) during vehicle water entry, encompassing theoretical modeling, experimental testing, and numerical simulation are reviewed. The theoretical analysis systematically traces the evolution from classical potential flow theory to nonlinear multiphysics-coupled models, while critically analyzing their applicability and limitations in complex entry scenarios. Experimental investigations summarize measurement techniques for capturing transient parameters and revealing physical mechanisms, highlighting their crucial role in validating theoretical and numerical frameworks, with particular attention to instrumentation constraints and boundary condition effects. Numerical advancements are examined through grid-based and meshless methodologies, emphasizing their computational characteristics in resolving multiphase flow evolution and FSI dynamics. Finally, current technical bottlenecks are identified, followed by forward-looking perspectives on multiscale coupling modeling and intelligent algorithm integration.

High-speed underwater vehicles are critical carriers for underwater high-speed penetration. To address their higher drag reduction demands, higher-performance underwater drag reduction technologies and more precise control techniques are required. Supercavitation drag reduction is primarily explored, which holds significant development potential, discussing its drag reduction mechanisms, component functions, and cavitation morphology changes. The current status and development level of supercavitation drag reduction technology theory, experimental validation techniques, and typical equipment are analyzed both domestically and internationally. Further, key issues in motion control for high-speed underwater vehicles are examined, researching control techniques such as linear feedback, robust pole placement, sliding mode variable structure, H-infinity robust control, and intelligent control, conducting research and application analysis on motion control methods. Areas requiring further research in current supercavitation drag reduction are also analyzed, including cavity stability issues, flow field simulation and validation for complex force-thermal physical processes, multiphase flow complex thermophysical process modeling, and robust stability design in highly nonlinear environments. Finally, from a future development perspective, it identifies unresolved problems such as perfecting fundamental mechanisms, intelligent control, algorithm innovation, structural innovation and interdisciplinary integration, and engineering validation. References for research on drag reduction and control technologies for high-speed underwater vehicles can be provided.