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.

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 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.

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.

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 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.

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.

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.

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.