Modelling methods of the high-altitude wind uncertainty have significant influence on aerodynamic loads and the overall performance optimization of launch vehicles. The commonly used methods in engineering do not consider the correlation between wind speeds at different altitudes, and the simulated wind samples are inconsistent with actual wind characteristics, therefore disable to accurately predict the aerodynamic loads. A modelling method using $U/V$ wind speed components as non-stationary Gaussian processes about the height is proposed. The statistical distribution parameters of massive actual historical wind samples are analyzed, and the expansion optimal linear estimation (EOLE) method is adopted to generate wind samples with the same distribution as actual wind samples. Results indicate that the proposed method can simulate the actual wind profile more precisely than traditional methods. The simulation program of real launch vehicle is used to calculate the wind loads, and the results show that the wind loads predicted by the proposed method is far more accurate than traditional methods, which is of great significance to improve the launch efficiency and launch probability of launch vehicles.

The use of deformable wing rudder technology can solve the problem of strong constraints on the launch platform size of missiles, improve the lift to drag ratio and ballistic maneuverability of missiles, achieve optimal aerodynamic shape throughout the flight, and adapt to the needs of multi mission operations. The development of deformable wing rudder technology at home and abroad is summarized, the composition of deformable wing rudder scheme is briefly introduced. The missile's demand for deformable wing rudder technology is analyzed, and the development path of single step deformation, reciprocating expansion deformation, flexible continuous deformation and the key technologies of each stage are put forward. The research results provide a reference for the in-depth research and application of deformable wing rudder technology in the field of missile weapons.

The expansion and locking process of aircraft folding rudder is a dynamic process of multi-load synthesis. The dynamic process is studied by simulation. The dynamic simulation model is established, considering aerodynamic load and friction action in the whole dynamic process. The influence of different aerodynamic load on dynamic process is analyzed by dynamically simulating the condition of obstruction, no-load and promoting aerodynamic load. By comparing the result of no-load expansion test with the simulation result of no-load condition, the accuracy of the dynamic simulation model is verified. Based on this dynamic simulation model, the friction work under different aerodynamic load condition is identified by using angular acceleration method and angular velocity method respectively from load and energy dimensions. The result of the study shows that the friction torque is affected by aerodynamic load. The friction work increases with the increase of aerodynamic promotion. The angular acceleration method and angular velocity method are both reasonable to identify the friction work. The research provides theoretical reference for engineering design and analysis of aircraft folding rudder.

The continuous reduction of fuel during the rocket launch causes the rocket structure to change continuously, and the natural frequency and modal shape of the structure also change accordingly. Aiming at the inaccuracy of the finite element model, the moment of inertia of the section is used as the correction parameter, and the minimum error between the numerical simulation results and the experimental test results under different states is the objective function, and an optimization model for multi-state model correction is established. The objective function is explicitly processed by sensitivity analysis and first-order Taylor expansion, and the optimal solution of design variables is obtained by sequential linear programming. At the same time, for the multi-state structure, taking the multi-section simply supported beam model as an example, the simply supported beam is tested by the hammering method, and the magnetic attraction weight scheme is designed to simulate the multi-state model. An optimization model is established for the objective function, and the multi-section simply supported beam model is revised to a single-section simply supported beam model after modification, and the ratio of the moment of inertia of the section to the area is met, which verifies the accuracy of the multi-state model modification method.

Super Heavy-Starship is a two-stage fully reusable heavy-lift launch vehicle proposed by Space Exploration Technologies Corp. (SpaceX). In Super Heavy-Starship, mechanisms are widely utilized to implement various functions of the launch vehicle, such as connection, separation, aerodynamic control and landing shock absorption. In addition, traditional pyrotechnics are replaced by high-pressure cold air as power source of mechanisms. Focusing on the landing shock absorption mechanism, grid rudder mechanism, flap rudder mechanism, stage separation mechanism, and pneumatic mechanism of Super Heavy-Starship, the mechanism composition, working principle, design ideas, merits and demerits are clarified. The innovation points of SpaceX's mechanisms are summarized. Furthermore, the gaps and deficiencies in the development and application of launch vehicle mechanisms in China are analyzed, and corresponding suggestions are put forward as well.

In response to the multiple ignition requirement of the expander cycle hydrogen-oxygen engine, research on the torch ignition system scheme is conducted, and a relatively reasonable low-pressure torch ignition system scheme is identified. The results show that the mixing ratio of the torch igniter fluctuated greatly when opening the hydrogen main valve, which may cause structural ablation. The scheme of introducing hydrogen from the inlet of the hydrogen turbine and liquid oxygen from the outlet of the liquid oxygen pump has a lower ablation risk, but it has a certain impact on the engine's start-up and steady-state characteristics. The low-pressure torch ignition start-up tests of liquid rocket engine are carried out for the first time in China. The experimental results verify the simulation results, and indicating the feasibility of the scheme.

In order to solve the possible problems of filling accuracy and kerosene quality in the drainage process of the closed filling pipeline at the end of the kerosene, the pipeline deformation caused by the change of pressure and temperature is discussed by analyzing the influencing factors that affect the change of kerosene in the pipeline. The thermodynamic calculation model of temperature, pipe diameter and deformation pressure is constructed, and the accuracy of the model calculation is verified by experiments. According to the numerical calculation results of the model, the optimization measures for the drainage process are proposed to ensure the reliability of the drainage process of the filling pipeline.

In the fault-tolerant control of polyphase motors, hysteresis control is generally adopted for the more complex non-sinusoidal fault-tolerant current obtained by multi-constraint solving. Compared with hysteresis control, voltage space vector control has the advantages of low torque ripple and low energy consumption, which is more common in the control of polyphase motors. In order to solve the problem that the non-sinusoidal fault-tolerant current cannot be decoupled directly for voltage space vector control, Fourier transform is introduced and the non-sinusoidal fault-tolerant current is decomposed into fundamental current and third harmonic current to realize the decoupling transformation of the non-sinusoidal fault-tolerant current. Based on this, the decoupling transformation matrix is derived and the correctness of the processing method is verified by simulation analysis. The results show that this method can solve the problem that the non-sinusoidal fault-tolerant current under open fault-tolerant control of polyphase permanent magnet synchronous motor cannot be directly applied to voltage space vector control, so as to reduce the torque ripple and improve the motor current stability.

The stability of shipborne platform in complex sea surface wind and wave environments is an important foundation for the operation of shipborne equipment. Attitude stability control for shipborne platform, an active disturbance rejection controller is designed, which improves the tracking accuracy of the shipborne platform to the target angle, ensures the rapid response of the system, and suppresses the influence of uncertain factors such as wind wave disturbance and load disturbance. In order to further improve the control effect of the controller, the particle swarm optimization algorithm is used to optimize the intelligent parameters of the controller. The simulation results show that the ADRC can improve the tracking speed, accuracy and robustness of the system.

The safety of solid rocket launch vehicles under the abnormal side tumbling condition in the process of railway transportation is studied. Based on investigation and analysis of various vibration absorption schemes, the technical scheme of energy absorption system with the combination of cushion airbag and honeycomb is put forward. The side-rolling simulation analysis is carried out using Hypermesh and LS-DYNA software. The results show that the acceleration of the rocket's side-rolling down decreases from 27g to 8.91g, and the contact collision force between the launcher and the carriage decreases from 382.59kN to non-contact by using the above technical scheme. Meanwhile, it can obviously improve the safety of solid rocket launch vehicles under abnormal conditions such as railway transport rollover. Finally, it provides important guidance for the design of special solid rocket launch vehicles.

To analyze the correlation characteristics between visible-infrared spectrum and infrared radiation of photonic crystal films, three kinds of Ge/ZnS photonic crystal films with different visible reflectance and the same infrared emissivity are designed. By simulating the infrared radiation characteristics of photonic crystal structures, the influence of solar illumination and reflection spectrum on the infrared radiation characteristics of the films in vacuum and atmospheric environments is discussed. The simulated results show that the difference of visible reflectance will lead to the discrepancy of surface temperature in the presence of sunlight. For infrared radiation, the high reflection surface will reflect solar radiation at low temperature for $3 \sim {5\mu}\mathrm{m}$ waveband, which has a negative impact on infrared camouflage. For $8 \sim {14\mu}\mathrm{m}$ waveband, when the infrared emissivity is low enough, the infrared radiation emittance of the photonic crystal structures is close. The fabrication of samples and the measurement of reflection spectrum and infrared thermography are carried out. The test results show the consistency with the simulation, and verify the infrared camouflage performance of three films. The research results are helpful to understand the visible-infrared spectrum and infrared radiation correlation characteristics of photonic crystal films, and provide reference for the spectral design and application scheme of visible-infrared camouflage materials compatible with microwave camouflage.

In order to control the riveting interference and minimize the damage of GFRP composite caused by riveting, it is necessary to study the influence trend of riveting squeeze force on the interference of ${\Phi4}\mathrm{\;{mm}}2\mathrm{A}{10}$ rivet. The dynamic riveting process and the interference of the rivet have been simulated by ABAQUS on the effects of diameter of pre-drilled hole and riveting squeeze force of ${\Phi4}\mathrm{\;{mm}}2\mathrm{A}{10}$ aluminum alloy rivet on GFRP composite and aluminum alloy layers. On the basis of the simulation the experimental investigations are performed. The Interference test and metallographic analysis of the specimens are conducted. Results indicate that the interference of the same measurement location in the rivet increases with the increase of the riveting squeeze force and the interference with the same riveting squeeze force decreases through-the-thickness. ${\Phi4.2}\mathrm{\;{mm}}$ diameter of pre-drilled hole and ${18.3}\sim {18.7}\mathrm{{kN}}$ riveting squeeze force can achieve the optimum interference and the GFRP composite has no apparent injuries.

In order to improve test efficiency of launch vehicle and optimize the process of prelaunch testing, and to alter the traditional method of disconnecting electric cables manually for leakage monitoring, based on maintaining the original power supply circuit, a leakage monitoring technology research for the medium frequency alternating current supply circuit is proposed and developed. At the same time, the precision of leakage monitoring circuit is analyzed and the self-detection method is used to advance the reliability and safety of the system. The test results show that the system realized online leakage monitoring lasting no less than 24hours, and the range of leakage monitoring is 500 kΩ~50 kΩ with the precision better than ±10%, satisfying the monitoring requirements. Finally, the system experiment is carried out in the prelaunch testing of large cryogenic launch vehicle with high-reliability, high-precision and high-efficiency, and has significance of improving the level of automated testing and realizing unattended fore-end of launch vehicle.

A modular hierarchical power supply and distribution method is proposed for electrical system of launch vehicles in order to avoid large scale power supply cable, complex topology and potential path. Each stage of electrical system is planned as an independent power supply and distribution unit, and the integrated power supply and distribution framework is realized in the unit. Electrical isolation is designed among different power supply and distribution units and ground equipment to prevent the electrical coupling and potential circle path and reduce the system complexity. The power and distribution system has the advantage of modularization in system level and the plug and play with units, which provides a technical basis for the standardized design of the power supply and distribution structure of the future electrical system and hierarchical test of the launch vehicle.

With the development of data bus technology and the increasing demand for low-cost and high-reliability electrical systems in "flight-based transportation", Field Bus(FB) is gradually favored by the aerospace field. Controller Area Network(CAN), one of the most widely used field buses, has been researched and applied in missiles and tactical rockets. Considering the differences between launch vehicles and missiles, the application of CAN bus in launch vehicle control systems is expounded. The necessity of research is firstly analyzed, then typical CAN topologies suitable for medium and large-scale launch vehicles are given respectively. For the aim of practical use, two corresponding technologies are introduced which are the CAN relay technology and the CAN bus reconstruction. The efficiency and load rate of CAN bus are calculated which are then compared with the ones derived by 1553B data transmission under the same conditions. These results can be referenced by designers in a more accurate sense.